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SUDO_PLUGIN(5)             File Formats Manual            SUDO_PLUGIN(5)

NAME         top

       sudo_plugin — Sudo Plugin API

DESCRIPTION         top

       Starting with version 1.8, sudo supports a plugin API for policy
       and session logging.  Plugins may be compiled as dynamic shared
       objects (the default on systems that support them) or compiled
       statically into the sudo binary itself.  By default, the sudoers
       plugin provides audit, security policy and I/O logging
       capabilities.  Via the plugin API, sudo can be configured to use
       alternate plugins provided by third parties.  The plugins to be
       used are specified in the sudo.conf(5) file.

       The API is versioned with a major and minor number.  The minor
       version number is incremented when additions are made.  The major
       number is incremented when incompatible changes are made.  A
       plugin should be check the version passed to it and make sure
       that the major version matches.

       The plugin API is defined by the <sudo_plugin.h> header file.

   Policy plugin API
       A policy plugin must declare and populate a struct policy_plugin
       in the global scope.  This structure contains pointers to the
       functions that implement the sudo policy checks.  The name of the
       symbol should be specified in sudo.conf(5) along with a path to
       the plugin so that sudo can load it.

       struct policy_plugin {
       #define SUDO_POLICY_PLUGIN     1
           unsigned int type; /* always SUDO_POLICY_PLUGIN */
           unsigned int version; /* always SUDO_API_VERSION */
           int (*open)(unsigned int version, sudo_conv_t conversation,
               sudo_printf_t sudo_plugin_printf, char * const settings[],
               char * const user_info[], char * const user_env[],
               char * const plugin_options[], const char **errstr);
           void (*close)(int exit_status, int error);
           int (*show_version)(int verbose);
           int (*check_policy)(int argc, char * const argv[],
               char *env_add[], char **command_info[],
               char **argv_out[], char **user_env_out[], const char **errstr);
           int (*list)(int argc, char * const argv[], int verbose,
               const char *user, const char **errstr);
           int (*validate)(const char **errstr);
           void (*invalidate)(int rmcred);
           int (*init_session)(struct passwd *pwd, char **user_env[],
               const char **errstr);
           void (*register_hooks)(int version,
              int (*register_hook)(struct sudo_hook *hook));
           void (*deregister_hooks)(int version,
              int (*deregister_hook)(struct sudo_hook *hook));
           struct sudo_plugin_event * (*event_alloc)(void);
       };

       A struct policy_plugin has the following fields:

       type  The type field should always be set to SUDO_POLICY_PLUGIN.

       version
             The version field should be set to SUDO_API_VERSION.

             This allows sudo to determine the API version the plugin
             was built against.

       open
             int (*open)(unsigned int version, sudo_conv_t conversation,
                 sudo_printf_t sudo_plugin_printf, char * const settings[],
                 char * const user_info[], char * const user_env[],
                 char * const plugin_options[], const char **errstr);

             Returns 1 on success, 0 on failure, -1 if a general error
             occurred, or -2 if there was a usage error.  In the latter
             case, sudo will print a usage message before it exits.  If
             an error occurs, the plugin may optionally call the
             conversation() or sudo_plugin_printf() function with
             SUDO_CONF_ERROR_MSG to present additional error information
             to the user.

             The function arguments are as follows:

             version
                   The version passed in by sudo allows the plugin to
                   determine the major and minor version number of the
                   plugin API supported by sudo.

             conversation
                   A pointer to the conversation() function that can be
                   used by the plugin to interact with the user (see
                   “Conversation API” for details).  Returns 0 on
                   success and -1 on failure.

             sudo_plugin_printf
                   A pointer to a printf()-style function that may be
                   used to display informational or error messages (see
                   “Conversation API” for details).  Returns the number
                   of characters printed on success and -1 on failure.

             settings
                   A vector of user-supplied sudo settings in the form
                   of “name=value” strings.  The vector is terminated by
                   a NULL pointer.  These settings correspond to options
                   the user specified when running sudo.  As such, they
                   will only be present when the corresponding option
                   has been specified on the command line.

                   When parsing settings, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   The following values may be set by sudo:

                   bsdauth_type=string
                         Authentication type, if specified by the -a
                         option, to use on systems where BSD
                         authentication is supported.

                   closefrom=number
                         If specified, the user has requested via the -C
                         option that sudo close all files descriptors
                         with a value of number or higher.  The plugin
                         may optionally pass this, or another value,
                         back in the command_info list.

                   cmnd_chroot=string
                         The root directory (see chroot(2)) to run the
                         command in, as specified by the user via the -R
                         option.  The plugin may ignore or restrict the
                         user's ability to specify a new root directory.
                         Only available starting with API version 1.16.

                   cmnd_cwd=string
                         The working directory to run the command in, as
                         specified by the user via the -D option.  The
                         plugin may ignore or restrict the user's
                         ability to specify a new working directory.
                         Only available starting with API version 1.16.

                   debug_flags=string
                         A debug file path name followed by a space and
                         a comma-separated list of debug flags that
                         correspond to the plugin's Debug entry in
                         sudo.conf(5), if there is one.  The flags are
                         passed to the plugin exactly as they appear in
                         sudo.conf(5).  The syntax used by sudo and the
                         sudoers plugin is subsystem@priority but a
                         plugin is free to use a different format so
                         long as it does not include a comma (‘,’).
                         Prior to sudo 1.8.12, there was no way to
                         specify plugin-specific debug_flags so the
                         value was always the same as that used by the
                         sudo front-end and did not include a path name,
                         only the flags themselves.  As of version 1.7
                         of the plugin interface, sudo will only pass
                         debug_flags if sudo.conf(5) contains a plugin-
                         specific Debug entry.

                   ignore_ticket=bool
                         Set to true if the user specified the -k option
                         along with a command, indicating that the user
                         wishes to ignore any cached authentication
                         credentials.  implied_shell to true.  This
                         allows sudo with no arguments to be used
                         similarly to su(1).  If the plugin does not to
                         support this usage, it may return a value of -2
                         from the check_policy() function, which will
                         cause sudo to print a usage message and exit.

                   implied_shell=bool
                         If the user does not specify a program on the
                         command line, sudo will pass the plugin the
                         path to the user's shell and set implied_shell.

                   intercept_ptrace=bool
                         Indicates whether or not the system supports
                         intercept mode using ptrace(2).  This is
                         currently only true for Linux systems that
                         support seccomp(2) filtering and the “trap”
                         action.  Other systems will use a dynamic
                         shared object to implement intercept.  Only
                         available starting with API version 1.19.

                   intercept_setid=bool
                         Indicates whether or not the system supports
                         running set-user-ID and set-group-ID binaries
                         in intercept mode.  This is currently only true
                         for Linux systems that support seccomp(2)
                         filtering and the “trap” action.  On systems
                         that use a dynamic shared object to implement
                         intercept, the dynamic linker (ld.so or the
                         equivalent) will disable preloading of shared
                         objects when executing a set-user-ID or set-
                         group-ID binary.  This will disable intercept
                         mode for that program and any other programs
                         that it executes.  The policy plugin may refuse
                         to execute a set-user-ID or set-group-ID binary
                         in intercept mode to avoid this.  Only
                         available starting with API version 1.19.

                   login_class=string
                         BSD login class to use when setting resource
                         limits and nice value, if specified by the -c
                         option.

                   login_shell=bool
                         Set to true if the user specified the -i
                         option, indicating that the user wishes to run
                         a login shell.

                   max_groups=int
                         The maximum number of groups a user may belong
                         to.  This will only be present if there is a
                         corresponding setting in sudo.conf(5).

                   network_addrs=list
                         A space-separated list of IP network addresses
                         and netmasks in the form “addr/netmask”, e.g.,
                         “192.168.1.2/255.255.255.0”.  The address and
                         netmask pairs may be either IPv4 or IPv6,
                         depending on what the operating system
                         supports.  If the address contains a colon
                         (‘:’), it is an IPv6 address, else it is IPv4.

                   noninteractive=bool
                         Set to true if the user specified the -n
                         option, indicating that sudo should operate in
                         non-interactive mode.  The plugin may reject a
                         command run in non-interactive mode if user
                         interaction is required.

                   plugin_dir=string
                         The default plugin directory used by the sudo
                         front-end.  This is the default directory set
                         at compile time and may not correspond to the
                         directory the running plugin was loaded from.
                         It may be used by a plugin to locate support
                         files.

                   plugin_path=string
                         The path name of plugin loaded by the sudo
                         front-end.  The path name will be a fully-
                         qualified unless the plugin was statically
                         compiled into sudo.

                   preserve_environment=bool
                         Set to true if the user specified the -E
                         option, indicating that the user wishes to
                         preserve the environment.

                   preserve_groups=bool
                         Set to true if the user specified the -P
                         option, indicating that the user wishes to
                         preserve the group vector instead of setting it
                         based on the runas user.

                   progname=string
                         The command name that sudo was run as,
                         typically “sudo” or “sudoedit”.

                   prompt=string
                         The prompt to use when requesting a password,
                         if specified via the -p option.

                   remote_host=string
                         The name of the remote host to run the command
                         on, if specified via the -h option.  Support
                         for running the command on a remote host is
                         meant to be implemented via a helper program
                         that is executed in place of the user-specified
                         command.  The sudo front-end is only capable of
                         executing commands on the local host.  Only
                         available starting with API version 1.4.

                   run_shell=bool
                         Set to true if the user specified the -s
                         option, indicating that the user wishes to run
                         a shell.

                   runas_group=string
                         The group name or group-ID to run the command
                         as, if specified via the -g option.

                   runas_user=string
                         The user name or user-ID to run the command as,
                         if specified via the -u option.

                   selinux_role=string
                         SELinux role to use when executing the command,
                         if specified by the -r option.

                   selinux_type=string
                         SELinux type to use when executing the command,
                         if specified by the -t option.

                   set_home=bool
                         Set to true if the user specified the -H
                         option.  If true, set the HOME environment
                         variable to the target user's home directory.

                   sudoedit=bool
                         Set to true when the -e option is specified or
                         if invoked as sudoedit.  The plugin shall
                         substitute an editor into argv in the
                         check_policy() function or return -2 with a
                         usage error if the plugin does not support
                         sudoedit.  For more information, see the
                         check_policy() section.

                   timeout=string
                         Command timeout specified by the user via the
                         -T option.  Not all plugins support command
                         timeouts and the ability of the user to set a
                         timeout may be restricted by policy.  The
                         format of the timeout string is plugin-
                         specific.

                   update_ticket=bool
                         Set to false if the user specified the -N
                         option, indicating that the user wishes to
                         avoid updating any cached authentication
                         credentials.  Only available starting with API
                         version 1.20.

                   Additional settings may be added in the future so the
                   plugin should silently ignore settings that it does
                   not recognize.

             user_info
                   A vector of information about the user running the
                   command in the form of “name=value” strings.  The
                   vector is terminated by a NULL pointer.

                   When parsing user_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   The following values may be set by sudo:

                   cols=int
                         The number of columns the user's terminal
                         supports.  If there is no terminal device
                         available, a default value of 80 is used.

                   cwd=string
                         The user's current working directory.

                   egid=gid_t
                         The effective group-ID of the user invoking
                         sudo.

                   euid=uid_t
                         The effective user-ID of the user invoking
                         sudo.

                   gid=gid_t
                         The real group-ID of the user invoking sudo.

                   groups=list
                         The user's supplementary group list formatted
                         as a string of comma-separated group-IDs.

                   host=string
                         The local machine's hostname as returned by the
                         gethostname(2) system call.

                   lines=int
                         The number of lines the user's terminal
                         supports.  If there is no terminal device
                         available, a default value of 24 is used.

                   pgid=int
                         The ID of the process group that the running
                         sudo process is a member of.  Only available
                         starting with API version 1.2.

                   pid=int
                         The process ID of the running sudo process.
                         Only available starting with API version 1.2.

                   ppid=int
                         The parent process ID of the running sudo
                         process.  Only available starting with API
                         version 1.2.

                   rlimit_as=soft,hard
                         The maximum size to which the process's address
                         space may grow (in bytes), if supported by the
                         operating system.  The soft and hard limits are
                         separated by a comma.  A value of “infinity”
                         indicates that there is no limit.  Only
                         available starting with API version 1.16.

                   rlimit_core=soft,hard
                         The largest size core dump file that may be
                         created (in bytes).  The soft and hard limits
                         are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   rlimit_cpu=soft,hard
                         The maximum amount of CPU time that the process
                         may use (in seconds).  The soft and hard limits
                         are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   rlimit_data=soft,hard
                         The maximum size of the data segment for the
                         process (in bytes).  The soft and hard limits
                         are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   rlimit_fsize=soft,hard
                         The largest size file that the process may
                         create (in bytes).  The soft and hard limits
                         are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   rlimit_locks=soft,hard
                         The maximum number of locks that the process
                         may establish, if supported by the operating
                         system.  The soft and hard limits are separated
                         by a comma.  A value of “infinity” indicates
                         that there is no limit.  Only available
                         starting with API version 1.16.

                   rlimit_memlock=soft,hard
                         The maximum size that the process may lock in
                         memory (in bytes), if supported by the
                         operating system.  The soft and hard limits are
                         separated by a comma.  A value of “infinity”
                         indicates that there is no limit.  Only
                         available starting with API version 1.16.

                   rlimit_nofile=soft,hard
                         The maximum number of files that the process
                         may have open.  The soft and hard limits are
                         separated by a comma.  A value of “infinity”
                         indicates that there is no limit.  Only
                         available starting with API version 1.16.

                   rlimit_nproc=soft,hard
                         The maximum number of processes that the user
                         may run simultaneously.  The soft and hard
                         limits are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   rlimit_rss=soft,hard
                         The maximum size to which the process's
                         resident set size may grow (in bytes).  The
                         soft and hard limits are separated by a comma.
                         A value of “infinity” indicates that there is
                         no limit.  Only available starting with API
                         version 1.16.

                   rlimit_stack=soft,hard
                         The maximum size to which the process's stack
                         may grow (in bytes).  The soft and hard limits
                         are separated by a comma.  A value of
                         “infinity” indicates that there is no limit.
                         Only available starting with API version 1.16.

                   sid=int
                         The session ID of the running sudo process or 0
                         if sudo is not part of a POSIX job control
                         session.  Only available starting with API
                         version 1.2.

                   tcpgid=int
                         The ID of the foreground process group
                         associated with the terminal device associated
                         with the sudo process or 0 if there is no
                         terminal present.  Only available starting with
                         API version 1.2.

                   tty=string
                         The path to the user's terminal device, if one
                         exists.  This entry is only present if the user
                         has a terminal device associated with the
                         session.

                   ttydev=dev_t
                         The number of the user's terminal device, if
                         one exists, in the form of a dev_t.  This entry
                         is only present if the user has a terminal
                         device associated with the session.  Only
                         available starting with API version 1.22.

                   uid=uid_t
                         The real user-ID of the user invoking sudo.

                   umask=octal
                         The invoking user's file creation mask.  Only
                         available starting with API version 1.10.

                   user=string
                         The name of the user invoking sudo.

             user_env
                   The user's environment in the form of a
                   NULL-terminated vector of “name=value” strings.

                   When parsing user_env, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             plugin_options
                   Any (non-comment) strings immediately after the
                   plugin path are passed as arguments to the plugin.
                   These arguments are split on a white space boundary
                   and are passed to the plugin in the form of a
                   NULL-terminated array of strings.  If no arguments
                   were specified, plugin_options will be the NULL
                   pointer.

                   The plugin_options parameter is only available
                   starting with API version 1.2.  A plugin must check
                   the API version specified by the sudo front-end
                   before using plugin_options.  Failure to do so may
                   result in a crash.

             errstr
                   If the open() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       close
             void (*close)(int exit_status, int error);

             The close() function is called when sudo is finished,
             shortly before it exits.  Starting with API version 1.15,
             close() is called regardless of whether or not a command
             was actually executed.  This makes it possible for plugins
             to perform cleanup even when a command was not run.  It is
             not possible to tell whether a command was run based solely
             on the arguments passed to the close() function.  To
             determine if a command was actually run, the plugin must
             keep track of whether or not the check_policy() function
             returned successfully.

             The function arguments are as follows:

             exit_status
                   The command's exit status, as returned by the wait(2)
                   system call, or zero if no command was run.  The
                   value of exit_status is undefined if error is non-
                   zero.

             error
                   If the command could not be executed, this is set to
                   the value of errno set by the execve(2) system call.
                   The plugin is responsible for displaying error
                   information via the conversation() or
                   sudo_plugin_printf() function.  If the command was
                   successfully executed, the value of error is zero.

             If no close() function is defined, no I/O logging plugins
             are loaded, and neither the timeout nor use_pty options are
             set in the command_info list, the sudo front-end may
             execute the command directly instead of running it as a
             child process.

       show_version
             int (*show_version)(int verbose);

             The show_version() function is called by sudo when the user
             specifies the -V option.  The plugin may display its
             version information to the user via the conversation() or
             sudo_plugin_printf() function using SUDO_CONV_INFO_MSG.  If
             the user requests detailed version information, the verbose
             flag will be non-zero.

             Returns 1 on success, 0 on failure, -1 if a general error
             occurred, or -2 if there was a usage error, although the
             return value is currently ignored.

       check_policy
             int (*check_policy)(int argc, char * const argv[], char *env_add[],
                 char **command_info[], char **argv_out[], char **user_env_out[],
                 const char **errstr);

             The check_policy() function is called by sudo to determine
             whether the user is allowed to run the specified commands.

             If the sudoedit option was enabled in the settings array
             passed to the open() function, the user has requested
             sudoedit mode.  sudoedit is a mechanism for editing one or
             more files where an editor is run with the user's
             credentials instead of with elevated privileges.  sudo
             achieves this by creating user-writable temporary copies of
             the files to be edited and then overwriting the originals
             with the temporary copies after editing is complete.  If
             the plugin supports sudoedit, it must set sudoedit=true in
             the command_info list.  The plugin is responsible for
             choosing the editor to be used, potentially from a variable
             in the user's environment, such as EDITOR, and should be
             stored in argv_out (environment variables may include
             command line options).  The files to be edited should be
             copied from argv to argv_out, separated from the editor and
             its arguments by a ‘--’ element.  The ‘--’ will be removed
             by sudo before the editor is executed.  The plugin may also
             set sudoedit_nfiles to the number of files to be edited in
             the command_info list; this will only be used by the sudo
             front-end starting with API version 1.21.

             The check_policy() function returns 1 if the command is
             allowed, 0 if not allowed, -1 for a general error, or -2
             for a usage error or if sudoedit was specified but is
             unsupported by the plugin.  In the latter case, sudo will
             print a usage message before it exits.  If an error occurs,
             the plugin may optionally call the conversation() or
             sudo_plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             argc  The number of elements in argv, not counting the
                   final NULL pointer.

             argv  The argument vector describing the command the user
                   wishes to run, in the same form as what would be
                   passed to the execve(2) system call.  The vector is
                   terminated by a NULL pointer.

             env_add
                   Additional environment variables specified by the
                   user on the command line in the form of a
                   NULL-terminated vector of “name=value” strings.  The
                   plugin may reject the command if one or more
                   variables are not allowed to be set, or it may
                   silently ignore such variables.

                   When parsing env_add, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             command_info
                   Information about the command being run in the form
                   of “name=value” strings.  These values are used by
                   sudo to set the execution environment when running a
                   command.  The plugin is responsible for creating and
                   populating the vector, which must be terminated with
                   a NULL pointer.  The following values are recognized
                   by sudo:

                   apparmor_profile=string
                         AppArmor profile to transition to when
                         executing the command.  Only available starting
                         with API version 1.19.

                   chroot=string
                         The root directory to use when running the
                         command.

                   closefrom=number
                         If specified, sudo will close all files
                         descriptors with a value of number or higher.

                   command=string
                         Fully qualified path to the command to be
                         executed.

                   cwd=string
                         The current working directory to change to when
                         executing the command.  If sudo is unable to
                         change to the new working directory, the
                         command will not be run unless cwd_optional is
                         also set (see below).

                   cwd_optional=bool
                         If set, sudo will treat an inability to change
                         to the new working directory as a non-fatal
                         error.  This setting has no effect unless cwd
                         is also set.

                   exec_background=bool
                         By default, sudo runs a command as the
                         foreground process as long as sudo itself is
                         running in the foreground.  When
                         exec_background is enabled and the command is
                         being run in a pseudo-terminal (due to I/O
                         logging or the use_pty setting), the command
                         will be run as a background process.  Attempts
                         to read from the controlling terminal (or to
                         change terminal settings) will result in the
                         command being suspended with the SIGTTIN signal
                         (or SIGTTOU in the case of terminal settings).
                         If this happens when sudo is a foreground
                         process, the command will be granted the
                         controlling terminal and resumed in the
                         foreground with no user intervention required.
                         The advantage of initially running the command
                         in the background is that sudo need not read
                         from the terminal unless the command explicitly
                         requests it.  Otherwise, any terminal input
                         must be passed to the command, whether it has
                         required it or not (the kernel buffers
                         terminals so it is not possible to tell whether
                         the command really wants the input).  This is
                         different from historic sudo behavior or when
                         the command is not being run in a pseudo-
                         terminal.

                         For this to work seamlessly, the operating
                         system must support the automatic restarting of
                         system calls.  Unfortunately, not all operating
                         systems do this by default, and even those that
                         do may have bugs.  For example, macOS fails to
                         restart the tcgetattr() and tcsetattr() system
                         calls (this is a bug in macOS).  Furthermore,
                         because this behavior depends on the command
                         stopping with the SIGTTIN or SIGTTOU signals,
                         programs that catch these signals and suspend
                         themselves with a different signal (usually
                         SIGTOP) will not be automatically foregrounded.
                         Some versions of the linux su(1) command behave
                         this way.  Because of this, a plugin should not
                         set exec_background unless it is explicitly
                         enabled by the administrator and there should
                         be a way to enabled or disable it on a per-
                         command basis.

                         This setting has no effect unless I/O logging
                         is enabled or use_pty is enabled.

                   execfd=number
                         If specified, sudo will use the fexecve(2)
                         system call to execute the command instead of
                         execve(2).  The specified number must refer to
                         an open file descriptor.

                   intercept=bool
                         If set, sudo will intercept attempts to execute
                         a subsequent command and perform a policy check
                         via the policy plugin's check_policy() function
                         to determine whether or not the command is
                         permitted.  This can be used to prevent shell
                         escapes on supported platforms but it has a
                         number of limitations.  See Preventing shell
                         escapes in sudoers(5) for details.  Only
                         available starting with API version 1.18.

                   intercept_verify=bool
                         If set, sudo will attempt to verify that a
                         command run in intercept mode has the expected
                         path name, command line arguments and
                         environment.  This setting has no effect unless
                         use_ptrace is also enabled.  Only available
                         starting with API version 1.20.

                   iolog_compress=bool
                         Set to true if the I/O logging plugins, if any,
                         should compress the log data.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_group=string
                         The group that will own newly created I/O log
                         files and directories.  This is a hint to the
                         I/O logging plugin which may choose to ignore
                         it.

                   iolog_mode=octal
                         The file permission mode to use when creating
                         I/O log files and directories.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_user=string
                         The user that will own newly created I/O log
                         files and directories.  This is a hint to the
                         I/O logging plugin which may choose to ignore
                         it.

                   iolog_path=string
                         Fully qualified path to the file or directory
                         in which I/O log is to be stored.  This is a
                         hint to the I/O logging plugin which may choose
                         to ignore it.  If no I/O logging plugin is
                         loaded, this setting has no effect.

                   iolog_stdin=bool
                         Set to true if the I/O logging plugins, if any,
                         should log the standard input if it is not
                         connected to a terminal device.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_stdout=bool
                         Set to true if the I/O logging plugins, if any,
                         should log the standard output if it is not
                         connected to a terminal device.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_stderr=bool
                         Set to true if the I/O logging plugins, if any,
                         should log the standard error if it is not
                         connected to a terminal device.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_ttyin=bool
                         Set to true if the I/O logging plugins, if any,
                         should log all terminal input.  This only
                         includes input typed by the user and not from a
                         pipe or redirected from a file.  This is a hint
                         to the I/O logging plugin which may choose to
                         ignore it.

                   iolog_ttyout=bool
                         Set to true if the I/O logging plugins, if any,
                         should log all terminal output.  This only
                         includes output to the screen, not output to a
                         pipe or file.  This is a hint to the I/O
                         logging plugin which may choose to ignore it.

                   login_class=string
                         BSD login class to use when setting resource
                         limits and nice value (optional).  This option
                         is only set on systems that support login
                         classes.

                   nice=int
                         Nice value (priority) to use when executing the
                         command.  The nice value, if specified,
                         overrides the priority associated with the
                         login_class on BSD systems.

                   log_subcmds=bool
                         If set, sudo will call the audit plugin's
                         accept() function to log when the command runs
                         a subsequent command, if supported by the
                         system.  If intercept is also specified,
                         log_subcmds will be ignored.  See Preventing
                         shell escapes in sudoers(5) for more
                         information.  Only available starting with API
                         version 1.18.

                   noexec=bool
                         If set, prevent the command from executing
                         other programs.

                   preserve_fds=list
                         A comma-separated list of file descriptors that
                         should be preserved, regardless of the value of
                         the closefrom setting.  Only available starting
                         with API version 1.5.

                   preserve_groups=bool
                         If set, sudo will preserve the user's group
                         vector instead of initializing the group vector
                         based on runas_user.

                   rlimit_as=soft,hard
                         The maximum size to which the process's address
                         space may grow (in bytes), if supported by the
                         operating system.  The soft and hard limits are
                         separated by a comma.  If only a single value
                         is specified, both the hard and soft limits are
                         set.  A value of “infinity” indicates that
                         there is no limit.  A value of “user” will
                         cause the invoking user's resource limit to be
                         preserved.  A value of “default” will cause the
                         target user's default resource limit to be used
                         on systems that allow per-user resource limits
                         to be configured.  Only available starting with
                         API version 1.18.

                   rlimit_core=soft,hard
                         The largest size core dump file that may be
                         created (in bytes).  The soft and hard limits
                         are separated by a comma.  If only a single
                         value is specified, both the hard and soft
                         limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   rlimit_cpu=soft,hard
                         The maximum amount of CPU time that the process
                         may use (in seconds).  The soft and hard limits
                         are separated by a comma.  If only a single
                         value is specified, both the hard and soft
                         limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   rlimit_data=soft,hard
                         The maximum size of the data segment for the
                         process (in bytes).  The soft and hard limits
                         are separated by a comma.  If only a single
                         value is specified, both the hard and soft
                         limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   rlimit_fsize=soft,hard
                         The largest size file that the process may
                         create (in bytes).  The soft and hard limits
                         are separated by a comma.  If only a single
                         value is specified, both the hard and soft
                         limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   rlimit_locks=soft,hard
                         The maximum number of locks that the process
                         may establish, if supported by the operating
                         system.  The soft and hard limits are separated
                         by a comma.  If only a single value is
                         specified, both the hard and soft limits are
                         set.  A value of “infinity” indicates that
                         there is no limit.  A value of “user” will
                         cause the invoking user's resource limit to be
                         preserved.  A value of “default” will cause the
                         target user's default resource limit to be used
                         on systems that allow per-user resource limits
                         to be configured.  Only available starting with
                         API version 1.18.

                   rlimit_memlock=soft,hard
                         The maximum size that the process may lock in
                         memory (in bytes), if supported by the
                         operating system.  The soft and hard limits are
                         separated by a comma.  If only a single value
                         is specified, both the hard and soft limits are
                         set.  A value of “infinity” indicates that
                         there is no limit.  A value of “user” will
                         cause the invoking user's resource limit to be
                         preserved.  A value of “default” will cause the
                         target user's default resource limit to be used
                         on systems that allow per-user resource limits
                         to be configured.  Only available starting with
                         API version 1.18.

                   rlimit_nofile=soft,hard
                         The maximum number of files that the process
                         may have open.  The soft and hard limits are
                         separated by a comma.  If only a single value
                         is specified, both the hard and soft limits are
                         set.  A value of “infinity” indicates that
                         there is no limit.  A value of “user” will
                         cause the invoking user's resource limit to be
                         preserved.  A value of “default” will cause the
                         target user's default resource limit to be used
                         on systems that allow per-user resource limits
                         to be configured.  Only available starting with
                         API version 1.18.

                   rlimit_nproc=soft,hard
                         The maximum number of processes that the user
                         may run simultaneously.  The soft and hard
                         limits are separated by a comma.  If only a
                         single value is specified, both the hard and
                         soft limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   rlimit_rss=soft,hard
                         The maximum size to which the process's
                         resident set size may grow (in bytes).  The
                         soft and hard limits are separated by a comma.
                         If only a single value is specified, both the
                         hard and soft limits are set.  A value of
                         “infinity” indicates that there is no limit.  A
                         value of “user” will cause the invoking user's
                         resource limit to be preserved.  A value of
                         “default” will cause the target user's default
                         resource limit to be used on systems that allow
                         per-user resource limits to be configured.
                         Only available starting with API version 1.18.

                   rlimit_stack=soft,hard
                         The maximum size to which the process's stack
                         may grow (in bytes).  The soft and hard limits
                         are separated by a comma.  If only a single
                         value is specified, both the hard and soft
                         limits are set.  A value of “infinity”
                         indicates that there is no limit.  A value of
                         “user” will cause the invoking user's resource
                         limit to be preserved.  A value of “default”
                         will cause the target user's default resource
                         limit to be used on systems that allow per-user
                         resource limits to be configured.  Only
                         available starting with API version 1.18.

                   runas_egid=gid
                         Effective group-ID to run the command as.  If
                         not specified, the value of runas_gid is used.

                   runas_euid=uid
                         Effective user-ID to run the command as.  If
                         not specified, the value of runas_uid is used.

                   runas_gid=gid
                         Group-ID to run the command as.

                   runas_group=string
                         The name of the group the command will run as,
                         if it is different from the runas_user's
                         default group.  This value is provided for
                         auditing purposes only, the sudo front-end uses
                         runas_egid and runas_gid when executing the
                         command.

                   runas_groups=list
                         The supplementary group vector to use for the
                         command in the form of a comma-separated list
                         of group-IDs.  If preserve_groups is set, this
                         option is ignored.

                   runas_uid=uid
                         User-ID to run the command as.

                   runas_user=string
                         The name of the user the command will run as,
                         which should correspond to runas_euid (or
                         runas_uid if runas_euid is not set).  This
                         value is provided for auditing purposes only,
                         the sudo front-end uses runas_euid and
                         runas_uid when executing the command.

                   selinux_role=string
                         SELinux role to use when executing the command.

                   selinux_type=string
                         SELinux type to use when executing the command.

                   set_utmp=bool
                         Create a utmp (or utmpx) entry when a pseudo-
                         terminal is allocated.  By default, the new
                         entry will be a copy of the user's existing
                         utmp entry (if any), with the tty, time, type,
                         and pid fields updated.

                   sudoedit=bool
                         Set to true when in sudoedit mode.  The plugin
                         may enable sudoedit mode even if sudo was not
                         invoked as sudoedit.  This allows the plugin to
                         perform command substitution and transparently
                         enable sudoedit when the user attempts to run
                         an editor.

                   sudoedit_checkdir=bool
                         Set to false to disable directory writability
                         checks in sudoedit.  By default, sudoedit
                         1.8.16 and higher will check all directory
                         components of the path to be edited for
                         writability by the invoking user.  Symbolic
                         links will not be followed in writable
                         directories and sudoedit will refuse to edit a
                         file located in a writable directory.  These
                         restrictions are not enforced when sudoedit is
                         run by root.  The sudoedit_checkdir option can
                         be set to false to disable this check.  Only
                         available starting with API version 1.8.

                   sudoedit_follow=bool
                         Set to true to allow sudoedit to edit files
                         that are symbolic links.  By default, sudoedit
                         1.8.15 and higher will refuse to open a
                         symbolic link.  The sudoedit_follow option can
                         be used to restore the older behavior and allow
                         sudoedit to open symbolic links.  Only
                         available starting with API version 1.8.

                   sudoedit_nfiles=number
                         The number of files to be edited by the user.
                         If present, this is will be used by the sudo
                         front-end to determine which elements of the
                         argv_out vector are files to be edited.  The
                         ‘--’ element must immediately precede the first
                         file to be editied.  If sudoedit_nfiles is not
                         specified, the sudo front-end will use the
                         position of the ‘--’ element to determine where
                         the file list begins.  Only available starting
                         with API version 1.21.

                   timeout=int
                         Command timeout.  If non-zero then when the
                         timeout expires the command will be killed.

                   umask=octal
                         The file creation mask to use when executing
                         the command.  This value may be overridden by
                         PAM or login.conf on some systems unless the
                         umask_override option is also set.

                   umask_override=bool
                         Force the value specified by the umask option
                         to override any umask set by PAM or login.conf.

                   use_ptrace=bool
                         If set, sudo will use ptrace(2) to implement
                         intercept mode if supported by the system.
                         This setting has no effect unless intercept is
                         also set.  Only available starting with API
                         version 1.19.

                   use_pty=bool
                         Allocate a pseudo-terminal to run the command
                         in, regardless of whether or not I/O logging is
                         in use.  By default, sudo will only run the
                         command in a pseudo-terminal when an I/O log
                         plugin is loaded.

                   utmp_user=string
                         User name to use when constructing a new utmp
                         (or utmpx) entry when set_utmp is enabled.
                         This option can be used to set the user field
                         in the utmp entry to the user the command runs
                         as rather than the invoking user.  If not set,
                         sudo will base the new entry on the invoking
                         user's existing entry.

                   Unsupported values will be ignored.

             argv_out
                   The NULL-terminated argument vector to pass to the
                   execve(2) system call when executing the command.
                   The plugin is responsible for allocating and
                   populating the vector.

             user_env_out
                   The NULL-terminated environment vector to use when
                   executing the command.  The plugin is responsible for
                   allocating and populating the vector.

             errstr
                   If the check_policy() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       list
             int (*list)(int argc, char * const argv[], int verbose,
                 const char *user, const char **errstr);

             List available privileges for the invoking user.  Returns 1
             on success, 0 on failure, and -1 on error.  On error, the
             plugin may optionally call the conversation() or
             sudo_plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             Privileges should be output via the conversation() or
             sudo_plugin_printf() function using SUDO_CONV_INFO_MSG.

             The function arguments are as follows:

             argc  The number of elements in argv, not counting the
                   final NULL pointer.

             argv  If non-NULL, an argument vector describing a command
                   the user wishes to check against the policy in the
                   same form as what would be passed to the execve(2)
                   system call.  If the command is permitted by the
                   policy, the fully-qualified path to the command
                   should be displayed along with any command line
                   arguments.

             verbose
                   Flag indicating whether to list in verbose mode or
                   not.

             user  The name of a different user to list privileges for
                   if the policy allows it.  If NULL, the plugin should
                   list the privileges of the invoking user.

             errstr
                   If the list() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       validate
             int (*validate)(const char **errstr);

             The validate() function is called when sudo is run with the
             -v option.  For policy plugins such as sudoers that cache
             authentication credentials, this function will validate and
             cache the credentials.

             The validate() function should be NULL if the plugin does
             not support credential caching.

             Returns 1 on success, 0 on failure, and -1 on error.  On
             error, the plugin may optionally call the conversation() or
             sudo_plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             errstr
                   If the validate() function returns a value other than
                   1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       invalidate
             void (*invalidate)(int rmcred);

             The invalidate() function is called when sudo is run with
             the -k or -K option.  For policy plugins such as sudoers
             that cache authentication credentials, this function will
             invalidate the credentials.  If the rmcred flag is non-
             zero, the plugin may remove the credentials instead of
             simply invalidating them.

             The invalidate() function should be NULL if the plugin does
             not support credential caching.

       init_session
             int (*init_session)(struct passwd *pwd, char **user_env[],
                 const char **errstr);

             The init_session() function is called before sudo sets up
             the execution environment for the command.  It is run in
             the parent sudo process before any user-ID or group-ID
             changes.  This can be used to perform session setup that is
             not supported by command_info, such as opening the PAM
             session.  The close() function can be used to tear down the
             session that was opened by init_session().

             Returns 1 on success, 0 on failure, and -1 on error.  On
             error, the plugin may optionally call the conversation() or
             sudo_plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             pwd   If the user-ID the command will run as was found in
                   the password database, pwd will describe that user,
                   otherwise it will be NULL.

             user_env_out
                   The NULL-terminated environment vector to use when
                   executing the command.  This is the same string
                   passed back to the front-end via the Policy Plugin's
                   user_env_out parameter.  If the init_session()
                   function needs to modify the user environment, it
                   should update the pointer stored in user_env_out.
                   The expected use case is to merge the contents of the
                   PAM environment (if any) with the contents of
                   user_env_out.  The user_env_out parameter is only
                   available starting with API version 1.2.  A plugin
                   must check the API version specified by the sudo
                   front-end before using user_env_out.  Failure to do
                   so may result in a crash.

             errstr
                   If the init_session() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       register_hooks
             void (*register_hooks)(int version,
                int (*register_hook)(struct sudo_hook *hook));

             The register_hooks() function is called by the sudo front-
             end to register any hooks the plugin needs.  If the plugin
             does not support hooks, register_hooks should be set to the
             NULL pointer.

             The version argument describes the version of the hooks API
             supported by the sudo front-end.

             The register_hook() function should be used to register any
             supported hooks the plugin needs.  It returns 0 on success,
             1 if the hook type is not supported, and -1 if the major
             version in struct sudo_hook does not match the front-end's
             major hook API version.

             See the “Hook function API” section below for more
             information about hooks.

             The register_hooks() function is only available starting
             with API version 1.2.  If the sudo front-end doesn't
             support API version 1.2 or higher, register_hooks() will
             not be called.

       deregister_hooks
             void (*deregister_hooks)(int version,
                int (*deregister_hook)(struct sudo_hook *hook));

             The deregister_hooks() function is called by the sudo
             front-end to deregister any hooks the plugin has
             registered.  If the plugin does not support hooks,
             deregister_hooks should be set to the NULL pointer.

             The version argument describes the version of the hooks API
             supported by the sudo front-end.

             The deregister_hook() function should be used to deregister
             any hooks that were put in place by the register_hook()
             function.  If the plugin tries to deregister a hook that
             the front-end does not support, deregister_hook() will
             return an error.

             See the “Hook function API” section below for more
             information about hooks.

             The deregister_hooks() function is only available starting
             with API version 1.2.  If the sudo front-end doesn't
             support API version 1.2 or higher, deregister_hooks() will
             not be called.

       event_alloc
             struct sudo_plugin_event * (*event_alloc)(void);

             The event_alloc() function is used to allocate a struct
             sudo_plugin_event which provides access to the main sudo
             event loop.  Unlike the other fields, the event_alloc
             pointer is filled in by the sudo front-end, not by the
             plugin.

             See the “Event API” section below for more information
             about events.

             The event_alloc() function is only available starting with
             API version 1.15.  If the sudo front-end doesn't support
             API version 1.15 or higher, event_alloc will not be set.

       Policy Plugin Version Macros

       /* Plugin API version major/minor. */
       #define SUDO_API_VERSION_MAJOR 1
       #define SUDO_API_VERSION_MINOR 13
       #define SUDO_API_MKVERSION(x, y) ((x << 16) | y)
       #define SUDO_API_VERSION SUDO_API_MKVERSION(SUDO_API_VERSION_MAJOR,\
                                                   SUDO_API_VERSION_MINOR)

       /* Getters and setters for API version */
       #define SUDO_API_VERSION_GET_MAJOR(v) ((v) >> 16)
       #define SUDO_API_VERSION_GET_MINOR(v) ((v) & 0xffff)
       #define SUDO_API_VERSION_SET_MAJOR(vp, n) do { \
           *(vp) = (*(vp) & 0x0000ffff) | ((n) << 16); \
       } while(0)
       #define SUDO_API_VERSION_SET_MINOR(vp, n) do { \
           *(vp) = (*(vp) & 0xffff0000) | (n); \
       } while(0)

   I/O plugin API
       struct io_plugin {
       #define SUDO_IO_PLUGIN 2
           unsigned int type; /* always SUDO_IO_PLUGIN */
           unsigned int version; /* always SUDO_API_VERSION */
           int (*open)(unsigned int version, sudo_conv_t conversation,
               sudo_printf_t sudo_plugin_printf, char * const settings[],
               char * const user_info[], char * const command_info[],
               int argc, char * const argv[], char * const user_env[],
               char * const plugin_options[], const char **errstr);
           void (*close)(int exit_status, int error); /* wait status or error */
           int (*show_version)(int verbose);
           int (*log_ttyin)(const char *buf, unsigned int len,
               const char **errstr);
           int (*log_ttyout)(const char *buf, unsigned int len,
               const char **errstr);
           int (*log_stdin)(const char *buf, unsigned int len,
               const char **errstr);
           int (*log_stdout)(const char *buf, unsigned int len,
               const char **errstr);
           int (*log_stderr)(const char *buf, unsigned int len,
               const char **errstr);
           void (*register_hooks)(int version,
              int (*register_hook)(struct sudo_hook *hook));
           void (*deregister_hooks)(int version,
              int (*deregister_hook)(struct sudo_hook *hook));
           int (*change_winsize)(unsigned int lines, unsigned int cols,
               const char **errstr);
           int (*log_suspend)(int signo, const char **errstr);
           struct sudo_plugin_event * (*event_alloc)(void);
       };

       When an I/O plugin is loaded, sudo runs the command in a pseudo-
       terminal.  This makes it possible to log the input and output
       from the user's session.  If any of the standard input, standard
       output, or standard error do not correspond to a tty, sudo will
       open a pipe to capture the I/O for logging before passing it on.

       The log_ttyin() function receives the raw user input from the
       terminal device (this will include input even when echo is
       disabled, such as when a password is read).  The log_ttyout()
       function receives output from the pseudo-terminal that is
       suitable for replaying the user's session at a later time.  The
       log_stdin(), log_stdout(), and log_stderr() functions are only
       called if the standard input, standard output, or standard error
       respectively correspond to something other than a tty.

       Any of the logging functions may be set to the NULL pointer if no
       logging is to be performed.  If the open function returns 0, no
       I/O will be sent to the plugin.

       If a logging function returns an error (-1), the running command
       will be terminated and all of the plugin's logging functions will
       be disabled.  Other I/O logging plugins will still receive any
       remaining input or output that has not yet been processed.

       If an input logging function rejects the data by returning 0, the
       command will be terminated and the data will not be passed to the
       command, though it will still be sent to any other I/O logging
       plugins.  If an output logging function rejects the data by
       returning 0, the command will be terminated and the data will not
       be written to the terminal, though it will still be sent to any
       other I/O logging plugins.

       A struct audit_plugin has the following fields:

       type  The type field should always be set to SUDO_IO_PLUGIN.

       version
             The version field should be set to SUDO_API_VERSION.

             This allows sudo to determine the API version the plugin
             was built against.

       open
             int (*open)(unsigned int version, sudo_conv_t conversation,
                 sudo_printf_t sudo_plugin_printf, char * const settings[],
                 char * const user_info[], char * const command_info[],
                 int argc, char * const argv[], char * const user_env[],
                 char * const plugin_options[]);

             The open() function is run before the log_ttyin(),
             log_ttyout(), log_stdin(), log_stdout(), log_stderr(),
             log_suspend(), change_winsize(), or show_version()
             functions are called.  It is only called if the version is
             being requested or if the policy plugin's check_policy()
             function has returned successfully.  It returns 1 on
             success, 0 on failure, -1 if a general error occurred, or
             -2 if there was a usage error.  In the latter case, sudo
             will print a usage message before it exits.  If an error
             occurs, the plugin may optionally call the conversation()
             or sudo_plugin_printf() function with SUDO_CONF_ERROR_MSG
             to present additional error information to the user.

             The function arguments are as follows:

             version
                   The version passed in by sudo allows the plugin to
                   determine the major and minor version number of the
                   plugin API supported by sudo.

             conversation
                   A pointer to the conversation() function that may be
                   used by the Fa(show_version) function to display
                   version information (see show_version() below).  The
                   conversation() function may also be used to display
                   additional error message to the user.  The
                   conversation() function returns 0 on success and -1
                   on failure.

             sudo_plugin_printf
                   A pointer to a printf()-style function that may be
                   used by the show_version() function to display
                   version information (see show_version below).  The
                   sudo_plugin_printf() function may also be used to
                   display additional error message to the user.  The
                   sudo_plugin_printf() function returns number of
                   characters printed on success and -1 on failure.

             settings
                   A vector of user-supplied sudo settings in the form
                   of “name=value” strings.  The vector is terminated by
                   a NULL pointer.  These settings correspond to options
                   the user specified when running sudo.  As such, they
                   will only be present when the corresponding option
                   has been specified on the command line.

                   When parsing settings, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible settings.

             user_info
                   A vector of information about the user running the
                   command in the form of “name=value” strings.  The
                   vector is terminated by a NULL pointer.

                   When parsing user_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             command_info
                   A vector of information describing the command being
                   run in the form of “name=value” strings.  The vector
                   is terminated by a NULL pointer.

                   When parsing command_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             argc  The number of elements in argv, not counting the
                   final NULL pointer.  It can be zero, such as when
                   sudo is called with the -V option.

             argv  If non-NULL, an argument vector describing a command
                   the user wishes to run in the same form as what would
                   be passed to the execve(2) system call.

             user_env
                   The user's environment in the form of a
                   NULL-terminated vector of “name=value” strings.

                   When parsing user_env, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             plugin_options
                   Any (non-comment) strings immediately after the
                   plugin path are treated as arguments to the plugin.
                   These arguments are split on a white space boundary
                   and are passed to the plugin in the form of a
                   NULL-terminated array of strings.  If no arguments
                   were specified, plugin_options will be the NULL
                   pointer.

                   The plugin_options parameter is only available
                   starting with API version 1.2.  A plugin must check
                   the API version specified by the sudo front-end
                   before using plugin_options.  Failure to do so may
                   result in a crash.

             errstr
                   If the open() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       close
             void (*close)(int exit_status, int error);

             The close() function is called when sudo is finished,
             shortly before it exits.

             The function arguments are as follows:

             exit_status
                   The command's exit status, as returned by the wait(2)
                   system call, or zero if no command was run.  The
                   value of exit_status is undefined if error is non-
                   zero.

             error
                   If the command could not be executed, this is set to
                   the value of errno set by the execve(2) system call.
                   If the command was successfully executed, the value
                   of error is zero.

       show_version
             int (*show_version)(int verbose);

             The show_version() function is called by sudo when the user
             specifies the -V option.  The plugin may display its
             version information to the user via the conversation() or
             sudo_plugin_printf() function using SUDO_CONV_INFO_MSG.  If
             the user requests detailed version information, the verbose
             flag will be non-zero.

             Returns 1 on success, 0 on failure, -1 if a general error
             occurred, or -2 if there was a usage error, although the
             return value is currently ignored.

       log_ttyin
             int (*log_ttyin)(const char *buf, unsigned int len,
                 const char **errstr);

             The log_ttyin() function is called whenever data can be
             read from the user but before it is passed to the running
             command.  This allows the plugin to reject data if it
             chooses to (for instance if the input contains banned
             content).  Returns 1 if the data should be passed to the
             command, 0 if the data is rejected (which will terminate
             the running command), or -1 if an error occurred.

             The function arguments are as follows:

             buf   The buffer containing user input.

             len   The length of buf in bytes.

             errstr
                   If the log_ttyin() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       log_ttyout
             int (*log_ttyout)(const char *buf, unsigned int len,
                 const char **errstr);

             The log_ttyout() function is called whenever data can be
             read from the command but before it is written to the
             user's terminal.  This allows the plugin to reject data if
             it chooses to (for instance if the output contains banned
             content).  Returns 1 if the data should be passed to the
             user, 0 if the data is rejected (which will terminate the
             running command), or -1 if an error occurred.

             The function arguments are as follows:

             buf   The buffer containing command output.

             len   The length of buf in bytes.

             errstr
                   If the log_ttyout() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       log_stdin
             int (*log_stdin)(const char *buf, unsigned int len,
                 const char **errstr);

             The log_stdin() function is only used if the standard input
             does not correspond to a tty device.  It is called whenever
             data can be read from the standard input but before it is
             passed to the running command.  This allows the plugin to
             reject data if it chooses to (for instance if the input
             contains banned content).  Returns 1 if the data should be
             passed to the command, 0 if the data is rejected (which
             will terminate the running command), or -1 if an error
             occurred.

             The function arguments are as follows:

             buf   The buffer containing user input.

             len   The length of buf in bytes.

             errstr
                   If the log_stdin() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       log_stdout
             int (*log_stdout)(const char *buf, unsigned int len,
                 const char **errstr);

             The log_stdout() function is only used if the standard
             output does not correspond to a tty device.  It is called
             whenever data can be read from the command but before it is
             written to the standard output.  This allows the plugin to
             reject data if it chooses to (for instance if the output
             contains banned content).  Returns 1 if the data should be
             passed to the user, 0 if the data is rejected (which will
             terminate the running command), or -1 if an error occurred.

             The function arguments are as follows:

             buf   The buffer containing command output.

             len   The length of buf in bytes.

             errstr
                   If the log_stdout() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       log_stderr
             int (*log_stderr)(const char *buf, unsigned int len,
                 const char **errstr);

             The log_stderr() function is only used if the standard
             error does not correspond to a tty device.  It is called
             whenever data can be read from the command but before it is
             written to the standard error.  This allows the plugin to
             reject data if it chooses to (for instance if the output
             contains banned content).  Returns 1 if the data should be
             passed to the user, 0 if the data is rejected (which will
             terminate the running command), or -1 if an error occurred.

             The function arguments are as follows:

             buf   The buffer containing command output.

             len   The length of buf in bytes.

             errstr
                   If the log_stderr() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       register_hooks
             See the “Policy plugin API” section for a description of
             register_hooks().

       deregister_hooks
             See the “Policy plugin API” section for a description of
             deregister_hooks().

       change_winsize
             int (*change_winsize)(unsigned int lines, unsigned int cols,
                 const char **errstr);

             The change_winsize() function is called whenever the window
             size of the terminal changes from the initial values
             specified in the user_info list.  Returns -1 if an error
             occurred, in which case no further calls to
             change_winsize() will be made,

             The function arguments are as follows:

             lines
                   The number of lines (rows) in the re-sized terminal.

             cols  The number of columns in the re-sized terminal.

             errstr
                   If the change_winsize() function returns a value
                   other than 1, the plugin may store a message
                   describing the failure or error in errstr.  The sudo
                   front-end will then pass this value to any registered
                   audit plugins.  The string stored in errstr must
                   remain valid until the plugin's close() function is
                   called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

       log_suspend
             int (*log_suspend)(int signo, const char **errstr);

             The log_suspend() function is called whenever a command is
             suspended or resumed.  Logging this information makes it
             possible to skip the period of time when the command was
             suspended during playback of a session.  Returns -1 if an
             error occurred, in which case no further calls to
             log_suspend() will be made,

             The function arguments are as follows:

             signo
                   The signal that caused the command to be suspended,
                   or SIGCONT if the command was resumed.

             errstr
                   If the log_suspend() function returns a value other
                   than 1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

                   The errstr parameter is only available starting with
                   API version 1.15.  A plugin must check the API
                   version specified by the sudo front-end before using
                   errstr.  Failure to do so may result in a crash.

             event_alloc
                   struct sudo_plugin_event * (*event_alloc)(void);

                   The event_alloc() function is used to allocate a
                   struct sudo_plugin_event which provides access to the
                   main sudo event loop.  Unlike the other fields, the
                   event_alloc() pointer is filled in by the sudo front-
                   end, not by the plugin.

                   See the “Event API” section below for more
                   information about events.

                   The event_alloc() function is only available starting
                   with API version 1.15.  If the sudo front-end doesn't
                   support API version 1.15 or higher, event_alloc()
                   will not be set.

             I/O Plugin Version Macros

             Same as for the “Policy plugin API”.

   Audit plugin API
       /* Audit plugin close function status types. */
       #define SUDO_PLUGIN_NO_STATUS           0
       #define SUDO_PLUGIN_WAIT_STATUS         1
       #define SUDO_PLUGIN_EXEC_ERROR          2
       #define SUDO_PLUGIN_SUDO_ERROR          3

       #define SUDO_AUDIT_PLUGIN 3
       struct audit_plugin {
           unsigned int type; /* always SUDO_AUDIT_PLUGIN */
           unsigned int version; /* always SUDO_API_VERSION */
           int (*open)(unsigned int version, sudo_conv_t conversation,
               sudo_printf_t sudo_plugin_printf, char * const settings[],
               char * const user_info[], int submit_optind,
               char * const submit_argv[], char * const submit_envp[],
               char * const plugin_options[], const char **errstr);
           void (*close)(int status_type, int status);
           int (*accept)(const char *plugin_name,
               unsigned int plugin_type, char * const command_info[],
               char * const run_argv[], char * const run_envp[],
               const char **errstr);
           int (*reject)(const char *plugin_name, unsigned int plugin_type,
               const char *audit_msg, char * const command_info[],
               const char **errstr);
           int (*error)(const char *plugin_name, unsigned int plugin_type,
               const char *audit_msg, char * const command_info[],
               const char **errstr);
           int (*show_version)(int verbose);
           void (*register_hooks)(int version,
               int (*register_hook)(struct sudo_hook *hook));
           void (*deregister_hooks)(int version,
               int (*deregister_hook)(struct sudo_hook *hook));
           struct sudo_plugin_event * (*event_alloc)(void);
       }

       An audit plugin can be used to log successful and unsuccessful
       attempts to run sudo independent of the policy or any I/O
       plugins.  Multiple audit plugins may be specified in
       sudo.conf(5).

       A struct audit_plugin has the following fields:

       type  The type field should always be set to SUDO_AUDIT_PLUGIN.

       version
             The version field should be set to SUDO_API_VERSION.

             This allows sudo to determine the API version the plugin
             was built against.

       open
             int (*open)(unsigned int version, sudo_conv_t conversation,
                 sudo_printf_t sudo_plugin_printf, char * const settings[],
                 char * const user_info[], int submit_optind,
                 char * const submit_argv[], char * const submit_envp[],
                 char * const plugin_options[], const char **errstr);

             The audit open() function is run before any other sudo
             plugin API functions.  This makes it possible to audit
             failures in the other plugins.  It returns 1 on success, 0
             on failure, -1 if a general error occurred, or -2 if there
             was a usage error.  In the latter case, sudo will print a
             usage message before it exits.  If an error occurs, the
             plugin may optionally call the conversation() or
             plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             version
                   The version passed in by sudo allows the plugin to
                   determine the major and minor version number of the
                   plugin API supported by sudo.

             conversation
                   A pointer to the conversation() function that may be
                   used by the show_version() function to display
                   version information (see show_version() below).  The
                   conversation() function may also be used to display
                   additional error message to the user.  The
                   conversation() function returns 0 on success, and -1
                   on failure.

             plugin_printf
                   A pointer to a printf()-style function that may be
                   used by the show_version() function to display
                   version information (see show_version below).  The
                   plugin_printf() function may also be used to display
                   additional error message to the user.  The
                   plugin_printf() function returns number of characters
                   printed on success and -1 on failure.

             settings
                   A vector of user-supplied sudo settings in the form
                   of “name=value” strings.  The vector is terminated by
                   a NULL pointer.  These settings correspond to options
                   the user specified when running sudo.  As such, they
                   will only be present when the corresponding option
                   has been specified on the command line.

                   When parsing settings, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible settings.

             user_info
                   A vector of information about the user running the
                   command in the form of “name=value” strings.  The
                   vector is terminated by a NULL pointer.

                   When parsing user_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             submit_optind
                   The index into submit_argv that corresponds to the
                   first entry that is not a command line option.  If
                   submit_argv only consists of options, which may be
                   the case with the -l or -v options,
                   submit_argv[submit_optind] will evaluate to the NULL
                   pointer.

             submit_argv
                   The argument vector sudo was invoked with, including
                   all command line options.  The submit_optind argument
                   can be used to determine the end of the command line
                   options.

             submit_envp
                   The invoking user's environment in the form of a
                   NULL-terminated vector of “name=value” strings.

                   When parsing submit_envp, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             plugin_options
                   Any (non-comment) strings immediately after the
                   plugin path are treated as arguments to the plugin.
                   These arguments are split on a white space boundary
                   and are passed to the plugin in the form of a
                   NULL-terminated array of strings.  If no arguments
                   were specified, plugin_options will be the NULL
                   pointer.

             errstr
                   If the open() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

       close
             void (*close)(int status_type, int status);

             The close() function is called when sudo is finished,
             shortly before it exits.

             The function arguments are as follows:

             status_type
                   The type of status being passed.  One of
                   SUDO_PLUGIN_NO_STATUS, SUDO_PLUGIN_WAIT_STATUS,
                   SUDO_PLUGIN_EXEC_ERROR or SUDO_PLUGIN_SUDO_ERROR.

             status
                   Depending on the value of status_type, this value is
                   either ignored, the command's exit status as returned
                   by the wait(2) system call, the value of errno set by
                   the execve(2) system call, or the value of errno
                   resulting from an error in the sudo front-end.

       accept
             int (*accept)(const char *plugin_name, unsigned int plugin_type,
                 char * const command_info[], char * const run_argv[],
                 char * const run_envp[], const char **errstr);

             The accept() function is called when a command or action is
             accepted by a policy or approval plugin.  The function
             arguments are as follows:

             plugin_name
                   The name of the plugin that accepted the command or
                   “sudo” for the sudo front-end.

             plugin_type
                   The type of plugin that accepted the command,
                   currently either SUDO_POLICY_PLUGIN,
                   SUDO_POLICY_APPROVAL, or SUDO_FRONT_END.  The
                   accept() function is called multiple times--once for
                   each policy or approval plugin that succeeds and once
                   for the sudo front-end.  When called on behalf of the
                   sudo front-end, command_info may include information
                   from an I/O logging plugin as well.

                   Typically, an audit plugin is interested in either
                   the accept status from the sudo front-end or from the
                   various policy and approval plugins, but not both.
                   It is possible for the policy plugin to accept a
                   command that is later rejected by an approval plugin,
                   in which case the audit plugin's accept() and
                   reject() functions will both be called.

             command_info
                   An optional vector of information describing the
                   command being run in the form of “name=value”
                   strings.  The vector is terminated by a NULL pointer.

                   When parsing command_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             run_argv
                   A NULL-terminated argument vector describing a
                   command that will be run in the same form as what
                   would be passed to the execve(2) system call.

             run_envp
                   The environment the command will be run with in the
                   form of a NULL-terminated vector of “name=value”
                   strings.

                   When parsing run_envp, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             errstr
                   If the accept() function returns a value other than
                   1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

       reject
             int (*reject)(const char *plugin_name, unsigned int plugin_type,
                 const char *audit_msg, char * const command_info[],
                 const char **errstr);

             The reject() function is called when a command or action is
             rejected by a plugin.  The function arguments are as
             follows:

             plugin_name
                   The name of the plugin that rejected the command.

             plugin_type
                   The type of plugin that rejected the command,
                   currently either SUDO_POLICY_PLUGIN,
                   SUDO_APPROVAL_PLUGIN, or SUDO_IO_PLUGIN.

                   Unlike the accept() function, the reject() function
                   is not called on behalf of the sudo front-end.

             audit_msg
                   An optional string describing the reason the command
                   was rejected by the plugin.  If the plugin did not
                   provide a reason, audit_msg will be the NULL pointer.

             command_info
                   An optional vector of information describing the
                   command being run in the form of “name=value”
                   strings.  The vector is terminated by a NULL pointer.

                   When parsing command_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             errstr
                   If the reject() function returns a value other than
                   1, the plugin may store a message describing the
                   failure or error in errstr.  The sudo front-end will
                   then pass this value to any registered audit plugins.
                   The string stored in errstr must remain valid until
                   the plugin's close() function is called.

       error
             int (*error)(const char *plugin_name, unsigned int plugin_type,
                 const char *audit_msg, char * const command_info[],
                 const char **errstr);

             The error() function is called when a plugin or the sudo
             front-end returns an error.  The function arguments are as
             follows:

             plugin_name
                   The name of the plugin that generated the error or
                   “sudo” for the sudo front-end.

             plugin_type
                   The type of plugin that generated the error, or
                   SUDO_FRONT_END for the sudo front-end.

             audit_msg
                   An optional string describing the plugin error.  If
                   the plugin did not provide a description, audit_msg
                   will be the NULL pointer.

             command_info
                   An optional vector of information describing the
                   command being run in the form of “name=value”
                   strings.  The vector is terminated by a NULL pointer.

                   When parsing command_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             errstr
                   If the error() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

       show_version
             int (*show_version)(int verbose);

             The show_version() function is called by sudo when the user
             specifies the -V option.  The plugin may display its
             version information to the user via the conversation() or
             plugin_printf() function using SUDO_CONV_INFO_MSG.  If the
             user requests detailed version information, the verbose
             flag will be set.

             Returns 1 on success, 0 on failure, -1 if a general error
             occurred, or -2 if there was a usage error, although the
             return value is currently ignored.

       register_hooks
             See the “Policy plugin API” section for a description of
             register_hooks().

       deregister_hooks
             See the “Policy plugin API” section for a description of
             deregister_hooks().

       event_alloc
             struct sudo_plugin_event * (*event_alloc)(void);

             The event_alloc() function is used to allocate a struct
             sudo_plugin_event which provides access to the main sudo
             event loop.  Unlike the other fields, the event_alloc
             pointer is filled in by the sudo front-end, not by the
             plugin.

             See the “Event API” section below for more information
             about events.

             The event_alloc() function is only available starting with
             API version 1.17.  If the sudo front-end doesn't support
             API version 1.17 or higher, event_alloc() will not be set.

   Approval plugin API
       struct approval_plugin {
       #define SUDO_APPROVAL_PLUGIN 4
           unsigned int type; /* always SUDO_APPROVAL_PLUGIN */
           unsigned int version; /* always SUDO_API_VERSION */
           int (*open)(unsigned int version, sudo_conv_t conversation,
               sudo_printf_t sudo_plugin_printf, char * const settings[],
               char * const user_info[], int submit_optind,
               char * const submit_argv[], char * const submit_envp[],
               char * const plugin_options[], const char **errstr);
           void (*close)(void);
           int (*check)(char * const command_info[], char * const run_argv[],
               char * const run_envp[], const char **errstr);
           int (*show_version)(int verbose);
       };

       An approval plugin can be used to apply extra constraints after a
       command has been accepted by the policy plugin.  Unlike the other
       plugin types, it does not remain open until the command
       completes.  The plugin is opened before a call to check() or
       show_version() and closed shortly thereafter (audit plugin
       functions must be called before the plugin is closed).  Multiple
       approval plugins may be specified in sudo.conf(5).

       A struct approval_plugin has the following fields:

       type  The type field should always be set to
             SUDO_APPROVAL_PLUGIN.

       version
             The version field should be set to SUDO_API_VERSION.

             This allows sudo to determine the API version the plugin
             was built against.

       open
             int (*open)(unsigned int version, sudo_conv_t conversation,
                 sudo_printf_t sudo_plugin_printf, char * const settings[],
                 char * const user_info[], int submit_optind,
                 char * const submit_argv[], char * const submit_envp[],
                 char * const plugin_options[], const char **errstr);

             The approval open() function is run immediately before a
             call to the plugin's check() or show_version() functions.
             It is only called if the version is being requested or if
             the policy plugin's check_policy() function has returned
             successfully.  It returns 1 on success, 0 on failure, -1 if
             a general error occurred, or -2 if there was a usage error.
             In the latter case, sudo will print a usage message before
             it exits.  If an error occurs, the plugin may optionally
             call the conversation() or plugin_printf() function with
             SUDO_CONF_ERROR_MSG to present additional error information
             to the user.

             The function arguments are as follows:

             version
                   The version passed in by sudo allows the plugin to
                   determine the major and minor version number of the
                   plugin API supported by sudo.

             conversation
                   A pointer to the conversation() function that can be
                   used by the plugin to interact with the user (see
                   “Conversation API” for details).  Returns 0 on
                   success and -1 on failure.

             plugin_printf
                   A pointer to a printf()-style function that may be
                   used to display informational or error messages (see
                   “Conversation API” for details).  Returns the number
                   of characters printed on success and -1 on failure.

             settings
                   A vector of user-supplied sudo settings in the form
                   of “name=value” strings.  The vector is terminated by
                   a NULL pointer.  These settings correspond to options
                   the user specified when running sudo.  As such, they
                   will only be present when the corresponding option
                   has been specified on the command line.

                   When parsing settings, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible settings.

             user_info
                   A vector of information about the user running the
                   command in the form of “name=value” strings.  The
                   vector is terminated by a NULL pointer.

                   When parsing user_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             submit_optind
                   The index into submit_argv that corresponds to the
                   first entry that is not a command line option.  If
                   submit_argv only consists of options, which may be
                   the case with the -l or -v options,
                   submit_argv[submit_optind] will evaluate to the NULL
                   pointer.

             submit_argv
                   The argument vector sudo was invoked with, including
                   all command line options.  The submit_optind argument
                   can be used to determine the end of the command line
                   options.

             submit_envp
                   The invoking user's environment in the form of a
                   NULL-terminated vector of “name=value” strings.

                   When parsing submit_envp, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             plugin_options
                   Any (non-comment) strings immediately after the
                   plugin path are treated as arguments to the plugin.
                   These arguments are split on a white space boundary
                   and are passed to the plugin in the form of a
                   NULL-terminated array of strings.  If no arguments
                   were specified, plugin_options will be the NULL
                   pointer.

             errstr
                   If the open() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

       close
             void (*close)(void);

             The close() function is called after the approval plugin's
             check() or show_version() functions have been called.  It
             takes no arguments.  The close() function is typically used
             to perform plugin-specific cleanup, such as the freeing of
             memory objects allocated by the plugin.  If the plugin does
             not need to perform any cleanup, close() may be set to the
             NULL pointer.

       check
             int (*check)(char * const command_info[], char * const run_argv[],
                 char * const run_envp[], const char **errstr);

             The approval check() function is run after the policy
             plugin check_policy() function and before any I/O logging
             plugins.  If multiple approval plugins are loaded, they
             must all succeed for the command to be allowed.  It returns
             1 on success, 0 on failure, -1 if a general error occurred,
             or -2 if there was a usage error.  In the latter case, sudo
             will print a usage message before it exits.  If an error
             occurs, the plugin may optionally call the conversation()
             or plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             command_info
                   A vector of information describing the command being
                   run in the form of “name=value” strings.  The vector
                   is terminated by a NULL pointer.

                   When parsing command_info, the plugin should split on
                   the first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

                   See the “Policy plugin API” section for a list of all
                   possible strings.

             run_argv
                   A NULL-terminated argument vector describing a
                   command that will be run in the same form as what
                   would be passed to the execve(2) system call.

             run_envp
                   The environment the command will be run with in the
                   form of a NULL-terminated vector of “name=value”
                   strings.

                   When parsing run_envp, the plugin should split on the
                   first equal sign (‘=’) since the name field will
                   never include one itself but the value might.

             errstr
                   If the open() function returns a value other than 1,
                   the plugin may store a message describing the failure
                   or error in errstr.  The sudo front-end will then
                   pass this value to any registered audit plugins.  The
                   string stored in errstr must remain valid until the
                   plugin's close() function is called.

       show_version
             int (*show_version)(int verbose);

             The show_version() function is called by sudo when the user
             specifies the -V option.  The plugin may display its
             version information to the user via the conversation() or
             plugin_printf() function using SUDO_CONV_INFO_MSG.  If the
             user requests detailed version information, the verbose
             flag will be set.

             Returns 1 on success, 0 on failure, -1 if a general error
             occurred, or -2 if there was a usage error, although the
             return value is currently ignored.

   Signal handlers
       The sudo front-end installs default signal handlers to trap
       common signals while the plugin functions are run.  The following
       signals are trapped by default before the command is executed:

       SIGALRM
       SIGHUP
       SIGINT
       SIGPIPE
       SIGQUIT
       SIGTERM
       SIGTSTP
       SIGUSR1
       SIGUSR2

       If a fatal signal is received before the command is executed,
       sudo will call the plugin's close() function with an exit status
       of 128 plus the value of the signal that was received.  This
       allows for consistent logging of commands killed by a signal for
       plugins that log such information in their close() function.  An
       exception to this is SIGPIPE, which is ignored until the command
       is executed.

       A plugin may temporarily install its own signal handlers but must
       restore the original handler before the plugin function returns.

   Hook function API
       Beginning with plugin API version 1.2, it is possible to install
       hooks for certain functions called by the sudo front-end.

       Currently, the only supported hooks relate to the handling of
       environment variables.  Hooks can be used to intercept attempts
       to get, set, or remove environment variables so that these
       changes can be reflected in the version of the environment that
       is used to execute a command.  A future version of the API will
       support hooking internal sudo front-end functions as well.

       Hook structure

       Hooks in sudo are described by the following structure:

       typedef int (*sudo_hook_fn_t)();

       struct sudo_hook {
           unsigned int hook_version;
           unsigned int hook_type;
           sudo_hook_fn_t hook_fn;
           void *closure;
       };

       A struct sudo_hook has the following fields:

       hook_version
             The hook_version field should be set to SUDO_HOOK_VERSION.

       hook_type
             The hook_type field may be one of the following supported
             hook types:

             SUDO_HOOK_SETENV
                   The C library setenv(3) function.  Any registered
                   hooks will run before the C library implementation.
                   The hook_fn field should be a function that matches
                   the following typedef:

                   typedef int (*sudo_hook_fn_setenv_t)(const char *name,
                      const char *value, int overwrite, void *closure);

                   If the registered hook does not match the typedef the
                   results are unspecified.

             SUDO_HOOK_UNSETENV
                   The C library unsetenv(3) function.  Any registered
                   hooks will run before the C library implementation.
                   The hook_fn field should be a function that matches
                   the following typedef:

                   typedef int (*sudo_hook_fn_unsetenv_t)(const char *name,
                      void *closure);

             SUDO_HOOK_GETENV
                   The C library getenv(3) function.  Any registered
                   hooks will run before the C library implementation.
                   The hook_fn field should be a function that matches
                   the following typedef:

                   typedef int (*sudo_hook_fn_getenv_t)(const char *name,
                      char **value, void *closure);

                   If the registered hook does not match the typedef the
                   results are unspecified.

             SUDO_HOOK_PUTENV
                   The C library putenv(3) function.  Any registered
                   hooks will run before the C library implementation.
                   The hook_fn field should be a function that matches
                   the following typedef:

                   typedef int (*sudo_hook_fn_putenv_t)(char *string,
                      void *closure);

                   If the registered hook does not match the typedef the
                   results are unspecified.

       hook_fn
             sudo_hook_fn_t hook_fn;

             The hook_fn field should be set to the plugin's hook
             implementation.  The actual function arguments will vary
             depending on the hook_type (see hook_type above).  In all
             cases, the closure field of struct sudo_hook is passed as
             the last function parameter.  This can be used to pass
             arbitrary data to the plugin's hook implementation.

             The function return value may be one of the following:

             SUDO_HOOK_RET_ERROR
                   The hook function encountered an error.

             SUDO_HOOK_RET_NEXT
                   The hook completed without error, go on to the next
                   hook (including the system implementation if
                   applicable).  For example, a getenv(3) hook might
                   return SUDO_HOOK_RET_NEXT if the specified variable
                   was not found in the private copy of the environment.

             SUDO_HOOK_RET_STOP
                   The hook completed without error, stop processing
                   hooks for this invocation.  This can be used to
                   replace the system implementation.  For example, a
                   setenv hook that operates on a private copy of the
                   environment but leaves environ unchanged.

       Care must be taken when hooking C library functions, it is very
       easy to create an infinite loop.  For example, a getenv(3) hook
       that calls the snprintf(3) function may create a loop if the
       snprintf(3) implementation calls getenv(3) to check the locale.
       To prevent this, you may wish to use a static variable in the
       hook function to guard against nested calls.  For example:

             static int in_progress = 0; /* avoid recursion */
             if (in_progress)
                 return SUDO_HOOK_RET_NEXT;
             in_progress = 1;
             ...
             in_progress = 0;
             return SUDO_HOOK_RET_STOP;

       Hook API Version Macros

       /* Hook API version major/minor */
       #define SUDO_HOOK_VERSION_MAJOR 1
       #define SUDO_HOOK_VERSION_MINOR 0
       #define SUDO_HOOK_VERSION SUDO_API_MKVERSION(SUDO_HOOK_VERSION_MAJOR,\
                                                     SUDO_HOOK_VERSION_MINOR)

       For getters and setters see the “Policy plugin API”.

   Event API
       When sudo runs a command, it uses an event loop to service
       signals and I/O.  Events may be triggered based on time, a file
       or socket descriptor becoming ready, or due to receipt of a
       signal.  Starting with API version 1.15, it is possible for a
       plugin to participate in this event loop by calling the
       event_alloc() function.

       Event structure

       Events are described by the following structure:

       typedef void (*sudo_plugin_ev_callback_t)(int fd, int what, void *closure);

       struct sudo_plugin_event {
           int (*set)(struct sudo_plugin_event *pev, int fd, int events,
               sudo_plugin_ev_callback_t callback, void *closure);
           int (*add)(struct sudo_plugin_event *pev, struct timespec *timeout);
           int (*del)(struct sudo_plugin_event *pev);
           int (*pending)(struct sudo_plugin_event *pev, int events,
               struct timespec *ts);
           int (*fd)(struct sudo_plugin_event *pev);
           void (*setbase)(struct sudo_plugin_event *pev, void *base);
           void (*loopbreak)(struct sudo_plugin_event *pev);
           void (*free)(struct sudo_plugin_event *pev);
       };

       A struct sudo_plugin_event contains the following function
       pointers:

       set
             int (*set)(struct sudo_plugin_event *pev, int fd, int events,
                 sudo_plugin_ev_callback_t callback, void *closure);

             The set() function takes the following arguments:

             struct sudo_plugin_event *pev
                   A pointer to the struct sudo_plugin_event itself.

             fd    The file or socket descriptor for I/O-based events or
                   the signal number for signal events.  For time-based
                   events, fd must be -1.

             events
                   The following values determine what will trigger the
                   event callback:

                   SUDO_PLUGIN_EV_TIMEOUT
                         callback is run after the specified timeout
                         expires

                   SUDO_PLUGIN_EV_READ
                         callback is run when the file descriptor is
                         readable

                   SUDO_PLUGIN_EV_WRITE
                         callback is run when the file descriptor is
                         writable

                   SUDO_PLUGIN_EV_PERSIST
                         event is persistent and remains enabled until
                         explicitly deleted

                   SUDO_PLUGIN_EV_SIGNAL
                         callback is run when the specified signal is
                         received

                   The SUDO_PLUGIN_EV_PERSIST flag may be ORed with any
                   of the event types.  It is also possible to OR
                   SUDO_PLUGIN_EV_READ and SUDO_PLUGIN_EV_WRITE together
                   to run the callback when a descriptor is ready to be
                   either read from or written to.  All other event
                   values are mutually exclusive.

             sudo_plugin_ev_callback_t callback
                   typedef void (*sudo_plugin_ev_callback_t)(int fd, int what,
                       void *closure);

                   The function to call when an event is triggered.  The
                   callback() function is run with the following
                   arguments:

                   fd    The file or socket descriptor for I/O-based
                         events or the signal number for signal events.

                   what  The event type that triggered that callback.
                         For events that have multiple event types (for
                         example SUDO_PLUGIN_EV_READ and
                         SUDO_PLUGIN_EV_WRITE) or have an associated
                         timeout, what can be used to determine why the
                         callback was run.

                   closure
                         The generic pointer that was specified in the
                         set() function.

             closure
                   A generic pointer that will be passed to the callback
                   function.

             The set() function returns 1 on success, and -1 if a error
             occurred.

       add
             int (*add)(struct sudo_plugin_event *pev, struct timespec *timeout);

             The add() function adds the event pev to sudo's event loop.
             The event must have previously been initialized via the
             set() function.  If the timeout argument is not NULL, it
             should specify a (relative) timeout after which the event
             will be triggered if the main event criteria has not been
             met.  This is often used to implement an I/O timeout where
             the event will fire if a descriptor is not ready within a
             certain time period.  If the event is already present in
             the event loop, its timeout will be adjusted to match the
             new value, if any.

             The add() function returns 1 on success, and -1 if a error
             occurred.

       del
             int (*del)(struct sudo_plugin_event *pev);

             The del() function deletes the event pev from sudo's event
             loop.  Deleted events can be added back via the add()
             function.

             The del() function returns 1 on success, and -1 if a error
             occurred.

       pending
             int (*pending)(struct sudo_plugin_event *pev, int events,
                 struct timespec *ts);

             The pending() function can be used to determine whether one
             or more events is pending.  The events argument specifies
             which events to check for.  See the set() function for a
             list of valid event types.  If SUDO_PLUGIN_EV_TIMEOUT is
             specified in events, the event has an associated timeout
             and the ts pointer is non-NULL, it will be filled in with
             the remaining time.

       fd
             int (*fd)(struct sudo_plugin_event *pev);

             The fd() function returns the descriptor or signal number
             associated with the event pev.

       setbase
             void (*setbase)(struct sudo_plugin_event *pev, void *base);

             The setbase() function sets the underlying event base for
             pev to the specified value.  This can be used to move an
             event created via event_alloc() to a new event loop
             allocated by sudo's event subsystem.  If base is NULL,
             pev's event base is reset to the default value, which
             corresponds to sudo's main event loop.  Using this function
             requires linking the plugin with the sudo_util library.  It
             is unlikely to be used outside of the sudoers plugin.

       loopbreak
             void (*loopbreak)(struct sudo_plugin_event *pev);

             The loopbreak() function causes sudo's event loop to exit
             immediately and the running command to be terminated.

       free
             void (*free)(struct sudo_plugin_event *pev);

             The free() function deletes the event pev from the event
             loop and frees the memory associated with it.

   Remote command execution
       The sudo front-end does not support running remote commands.
       However, starting with sudo 1.8.8, the -h option may be used to
       specify a remote host that is passed to the policy plugin.  A
       plugin may also accept a runas_user in the form of
       “user@hostname” which will work with older versions of sudo.  It
       is anticipated that remote commands will be supported by
       executing a “helper” program.  The policy plugin should setup the
       execution environment such that the sudo front-end will run the
       helper which, in turn, will connect to the remote host and run
       the command.

       For example, the policy plugin could utilize ssh to perform
       remote command execution.  The helper program would be
       responsible for running ssh with the proper options to use a
       private key or certificate that the remote host will accept and
       run a program on the remote host that would setup the execution
       environment accordingly.

       Remote sudoedit functionality must be handled by the policy
       plugin, not sudo itself as the front-end has no knowledge that a
       remote command is being executed.  This may be addressed in a
       future revision of the plugin API.

   Conversation API
       If the plugin needs to interact with the user, it may do so via
       the conversation() function.  A plugin should not attempt to read
       directly from the standard input or the user's terminal (neither
       of which are guaranteed to exist).  The caller must include a
       trailing newline in msg if one is to be printed.

       A printf()-style function is also available that can be used to
       display informational or error messages to the user, which is
       usually more convenient for simple messages where no use input is
       required.

       Conversation function structures

       The conversation function takes as arguments pointers to the
       following structures:

       struct sudo_conv_message {
       #define SUDO_CONV_PROMPT_ECHO_OFF  0x0001 /* do not echo user input */
       #define SUDO_CONV_PROMPT_ECHO_ON   0x0002 /* echo user input */
       #define SUDO_CONV_ERROR_MSG        0x0003 /* error message */
       #define SUDO_CONV_INFO_MSG         0x0004 /* informational message */
       #define SUDO_CONV_PROMPT_MASK      0x0005 /* mask user input */
       #define SUDO_CONV_PROMPT_ECHO_OK   0x1000 /* flag: allow echo if no tty */
       #define SUDO_CONV_PREFER_TTY       0x2000 /* flag: use tty if possible */
           int msg_type;
           int timeout;
           const char *msg;
       };

       #define SUDO_CONV_REPL_MAX      1023

       struct sudo_conv_reply {
           char *reply;
       };

       typedef int (*sudo_conv_callback_fn_t)(int signo, void *closure);
       struct sudo_conv_callback {
           unsigned int version;
           void *closure;
           sudo_conv_callback_fn_t on_suspend;
           sudo_conv_callback_fn_t on_resume;
       };

       Pointers to the conversation() and printf()-style functions are
       passed in to the plugin's open() function when the plugin is
       initialized.  The following type definitions can be used in the
       declaration of the open() function:

       typedef int (*sudo_conv_t)(int num_msgs,
           const struct sudo_conv_message msgs[],
           struct sudo_conv_reply replies[], struct sudo_conv_callback *callback);

       typedef int (*sudo_printf_t)(int msg_type, const char * restrict fmt, ...);

       To use the conversation() function, the plugin must pass an array
       of struct sudo_conv_message and struct sudo_conv_reply.  There
       must be a struct sudo_conv_message and struct sudo_conv_reply for
       each message in the conversation, that is, both arrays must have
       the same number of elements.  Each struct sudo_conv_reply must
       have its reply member initialized to NULL.  The struct
       sudo_conv_callback pointer, if not NULL, should contain function
       pointers to be called when the sudo process is suspended and/or
       resumed during conversation input.  The on_suspend and on_resume
       functions are called with the signal that caused sudo to be
       suspended and the closure pointer from the struct
       sudo_conv_callback.  These functions should return 0 on success
       and -1 on error.  On error, the conversation will end and the
       conversation function will return a value of -1.  The intended
       use is to allow the plugin to release resources, such as locks,
       that should not be held indefinitely while suspended and then
       reacquire them when the process is resumed.  The functions are
       not actually invoked from within a signal handler.

       The msg_type must be set to one of the following values:

       SUDO_CONV_PROMPT_ECHO_OFF
             Prompt the user for input with echo disabled; this is
             generally used for passwords.  The reply will be stored in
             the replies array, and it will never be NULL.

       SUDO_CONV_PROMPT_ECHO_ON
             Prompt the user for input with echo enabled.  The reply
             will be stored in the replies array, and it will never be
             NULL.

       SUDO_CONV_ERROR_MSG
             Display an error message.  The message is written to the
             standard error unless the SUDO_CONV_PREFER_TTY flag is set,
             in which case it is written to the user's terminal if
             possible.

       SUDO_CONV_INFO_MSG
             Display a message.  The message is written to the standard
             output unless the SUDO_CONV_PREFER_TTY flag is set, in
             which case it is written to the user's terminal if
             possible.

       SUDO_CONV_PROMPT_MASK
             Prompt the user for input but echo an asterisk character
             for each character read.  The reply will be stored in the
             replies array, and it will never be NULL.  This can be used
             to provide visual feedback to the user while reading
             sensitive information that should not be displayed.

       In addition to the above values, the following flag bits may also
       be set:

       SUDO_CONV_PROMPT_ECHO_OK
             Allow input to be read when echo cannot be disabled when
             the message type is SUDO_CONV_PROMPT_ECHO_OFF or
             SUDO_CONV_PROMPT_MASK.  By default, sudo will refuse to
             read input if the echo cannot be disabled for those message
             types.

       SUDO_CONV_PREFER_TTY
             When displaying a message via SUDO_CONV_ERROR_MSG or
             SUDO_CONV_INFO_MSG, try to write the message to the user's
             terminal.  If the terminal is unavailable, the standard
             error or standard output will be used, depending upon
             whether SUDO_CONV_ERROR_MSG or SUDO_CONV_INFO_MSG was used.
             The user's terminal is always used when possible for input,
             this flag is only used for output.

       The timeout in seconds until the prompt will wait for no more
       input.  A zero value implies an infinite timeout.

       The plugin is responsible for freeing the reply buffer located in
       each struct sudo_conv_reply, if it is not NULL.
       SUDO_CONV_REPL_MAX represents the maximum length of the reply
       buffer (not including the trailing NUL character).  In practical
       terms, this is the longest password sudo will support.

       The printf()-style function uses the same underlying mechanism as
       the conversation() function but only supports SUDO_CONV_INFO_MSG
       and SUDO_CONV_ERROR_MSG for the msg_type parameter.  It can be
       more convenient than using the conversation() function if no user
       reply is needed and supports standard printf() escape sequences.

       See the sample plugin for an example of the conversation()
       function usage.

   Plugin invocation order
       As of sudo 1.9.0, the plugin open() and close() functions are
       called in the following order:

       1.   audit open

       2.   policy open

       3.   approval open

       4.   approval close

       5.   I/O log open

       6.   command runs

       7.   command exits

       8.   I/O log close

       9.   policy close

       10.  audit close

       11.  sudo exits

       Prior to sudo 1.9.0, the I/O log close() function was called
       after the policy close() function.

   Sudoers group plugin API
       The sudoers plugin supports its own plugin interface to allow
       non-Unix group lookups.  This can be used to query a group source
       other than the standard Unix group database.  Two sample group
       plugins are bundled with sudo, group_file, and system_group, are
       detailed in sudoers(5).  Third party group plugins include a QAS
       AD plugin available from Quest Software.

       A group plugin must declare and populate a struct
       sudoers_group_plugin in the global scope.  This structure
       contains pointers to the functions that implement plugin
       initialization, cleanup, and group lookup.

       struct sudoers_group_plugin {
           unsigned int version;
           int (*init)(int version, sudo_printf_t sudo_plugin_printf,
               char *const argv[]);
           void (*cleanup)(void);
           int (*query)(const char *user, const char *group,
               const struct passwd *pwd);
       };

       A struct sudoers_group_plugin has the following fields:

       version
             The version field should be set to GROUP_API_VERSION.

             This allows sudoers to determine the API version the group
             plugin was built against.

       init
             int (*init)(int version, sudo_printf_t sudo_plugin_printf,
                 char *const argv[]);

             The init() function is called after sudoers has been parsed
             but before any policy checks.  It returns 1 on success, 0
             on failure (or if the plugin is not configured), and -1 if
             a error occurred.  If an error occurs, the plugin may call
             the plugin_printf() function with SUDO_CONF_ERROR_MSG to
             present additional error information to the user.

             The function arguments are as follows:

             version
                   The version passed in by sudoers allows the plugin to
                   determine the major and minor version number of the
                   group plugin API supported by sudoers.

             plugin_printf
                   A pointer to a printf()-style function that may be
                   used to display informational or error message to the
                   user.  Returns the number of characters printed on
                   success and -1 on failure.

             argv  A NULL-terminated array of arguments generated from
                   the group_plugin option in sudoers.  If no arguments
                   were given, argv will be NULL.

       cleanup
             void (*cleanup)();

             The cleanup() function is called when sudoers has finished
             its group checks.  The plugin should free any memory it has
             allocated and close open file handles.

       query
             int (*query)(const char *user, const char *group,
                 const struct passwd *pwd);

             The query() function is used to ask the group plugin
             whether user is a member of group.

             The function arguments are as follows:

             user  The name of the user being looked up in the external
                   group database.

             group
                   The name of the group being queried.

             pwd   The password database entry for user, if any.  If
                   user is not present in the password database, pwd
                   will be NULL.

       Group API Version Macros

       /* Sudoers group plugin version major/minor */
       #define GROUP_API_VERSION_MAJOR 1
       #define GROUP_API_VERSION_MINOR 0
       #define GROUP_API_VERSION ((GROUP_API_VERSION_MAJOR << 16) | \
                                  GROUP_API_VERSION_MINOR)
       For getters and setters see the “Policy plugin API”.

PLUGIN API CHANGELOG         top

       The following revisions have been made to the Sudo Plugin API.

       Version 1.0
             Initial API version.

       Version 1.1 (sudo 1.8.0)
             The I/O logging plugin's open() function was modified to
             take the command_info list as an argument.

       Version 1.2 (sudo 1.8.5)
             The Policy and I/O logging plugins' open() functions are
             now passed a list of plugin parameters if any are specified
             in sudo.conf(5).

             A simple hooks API has been introduced to allow plugins to
             hook in to the system's environment handling functions.

             The init_session() Policy plugin function is now passed a
             pointer to the user environment which can be updated as
             needed.  This can be used to merge in environment variables
             stored in the PAM handle before a command is run.

       Version 1.3 (sudo 1.8.7)
             Support for the exec_background entry has been added to the
             command_info list.

             The max_groups and plugin_dir entries were added to the
             settings list.

             The version() and close() functions are now optional.
             Previously, a missing version() or close() function would
             result in a crash.  If no policy plugin close() function is
             defined, a default close() function will be provided by the
             sudo front-end that displays a warning if the command could
             not be executed.

             The sudo front-end now installs default signal handlers to
             trap common signals while the plugin functions are run.

       Version 1.4 (sudo 1.8.8)
             The remote_host entry was added to the settings list.

       Version 1.5 (sudo 1.8.9)
             The preserve_fds entry was added to the command_info list.

       Version 1.6 (sudo 1.8.11)
             The behavior when an I/O logging plugin returns an error
             (-1) has changed.  Previously, the sudo front-end took no
             action when the log_ttyin(), log_ttyout(), log_stdin(),
             log_stdout(), or log_stderr() function returned an error.

             The behavior when an I/O logging plugin returns 0 has
             changed.  Previously, output from the command would be
             displayed to the terminal even if an output logging
             function returned 0.

       Version 1.7 (sudo 1.8.12)
             The plugin_path entry was added to the settings list.

             The debug_flags entry now starts with a debug file path
             name and may occur multiple times if there are multiple
             plugin-specific Debug lines in the sudo.conf(5) file.

       Version 1.8 (sudo 1.8.15)
             The sudoedit_checkdir and sudoedit_follow entries were
             added to the command_info list.  The default value of
             sudoedit_checkdir was changed to true in sudo 1.8.16.

             The sudo conversation() function now takes a pointer to a
             struct sudo_conv_callback as its fourth argument.  The
             sudo_conv_t definition has been updated to match.  The
             plugin must specify that it supports plugin API version 1.8
             or higher to receive a conversation function pointer that
             supports this argument.

       Version 1.9 (sudo 1.8.16)
             The execfd entry was added to the command_info list.

       Version 1.10 (sudo 1.8.19)
             The umask entry was added to the user_info list.  The
             iolog_group, iolog_mode, and iolog_user entries were added
             to the command_info list.

       Version 1.11 (sudo 1.8.20)
             The timeout entry was added to the settings list.

       Version 1.12 (sudo 1.8.21)
             The change_winsize() function was added to struct
             io_plugin.

       Version 1.13 (sudo 1.8.26)
             The log_suspend() function was added to struct io_plugin.

       Version 1.14 (sudo 1.8.29)
             The umask_override entry was added to the command_info
             list.

       Version 1.15 (sudo 1.9.0)
             The cwd_optional entry was added to the command_info list.

             The event_alloc() function was added to struct
             policy_plugin and struct io_plugin.

             The errstr argument was added to the policy and I/O plugin
             functions which the plugin function can use to return an
             error string.  This string may be used by the audit plugin
             to report failure or error conditions set by the other
             plugins.

             The close() function is now is called regardless of whether
             or not a command was actually executed.  This makes it
             possible for plugins to perform cleanup even when a command
             was not run.

             SUDO_CONV_REPL_MAX has increased from 255 to 1023 bytes.

             Support for audit and approval plugins was added.

       Version 1.16 (sudo 1.9.3)
             Initial resource limit values were added to the user_info
             list.

             The cmnd_chroot and cmnd_cwd entries were added to the
             settings list.

       Version 1.17 (sudo 1.9.4)
             The event_alloc() function was added to struct audit_plugin
             and struct approval_plugin.

       Version 1.18 (sudo 1.9.9)
             The policy may now set resource limit values in the
             command_info list.  The intercept and log_subcmds entries
             were added to the command_info list.

       Version 1.19 (sudo 1.9.11)
             The intercept_ptrace and intercept_setid entries were added
             to the settings list.  The apparmor_profile and use_ptrace
             entries were added to the command_info list.

       Version 1.20 (sudo 1.9.12)
             The update_ticket entry was added to the settings list.
             The intercept_verify entry was added to the command_info
             list.

       Version 1.21 (sudo 1.9.13)
             The sudoedit_nfiles entry was added to the command_info
             list.

       Version 1.22 (sudo 1.9.16)
             The ttydev entry was added to the user_info list.

SEE ALSO         top

       sudo.conf(5), sudoers(5), sudo(8)

AUTHORS         top

       Many people have worked on sudo over the years; this version
       consists of code written primarily by:

             Todd C. Miller

       See the CONTRIBUTORS.md file in the sudo distribution
       (https://www.sudo.ws/about/contributors/) for an exhaustive list
       of people who have contributed to sudo.

BUGS         top

       If you believe you have found a bug in sudo, you can submit a bug
       report at https://bugzilla.sudo.ws/

SUPPORT         top

       Limited free support is available via the sudo-users mailing
       list, see https://www.sudo.ws/mailman/listinfo/sudo-users to
       subscribe or search the archives.

DISCLAIMER         top

       sudo is provided “AS IS” and any express or implied warranties,
       including, but not limited to, the implied warranties of
       merchantability and fitness for a particular purpose are
       disclaimed.  See the LICENSE.md file distributed with sudo or
       https://www.sudo.ws/about/license/ for complete details.

COLOPHON         top

       This page is part of the sudo (execute a command as another user)
       project.  Information about the project can be found at
       https://www.sudo.ws/.  If you have a bug report for this manual
       page, see ⟨https://bugzilla.sudo.ws/⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/sudo-project/sudo⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2023-12-21.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

Sudo 1.9.15p4               November 25, 2023             SUDO_PLUGIN(5)