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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | COPYING | NOTES | COLOPHON |
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LIBTRACEFS(3) libtracefs Manual LIBTRACEFS(3)
tracefs_get_tracing_file, tracefs_put_tracing_file,
tracefs_tracing_dir, tracefs_debug_dir, tracefs_set_tracing_dir,
tracefs_tracing_dir_is_mounted - Find and set locations of trace
directory and files.
#include <tracefs.h>
char *tracefs_get_tracing_file(const char *name);
void tracefs_put_tracing_file(char *name);
const char *tracefs_tracing_dir(void);
const char *tracefs_debug_dir(void);
int tracefs_set_tracing_dir(char *tracing_dir)
int tracefs_tracing_dir_is_mounted(bool mount, const char **path);
This set of APIs can be used to find the full path of the trace
file system mount point and trace files in it.
The tracefs_set_tracing_dir() function sets a custom location of
the system’s tracing directory mount point. Usually, the library
auto detects it using the information from the /proc/mounts file.
Use this API only if the mount point is not standard and cannot be
detected by the library. The tracing_dir argument can be NULL, in
that case the custom location is deleted and the library auto
detection logic is used.
The tracefs_get_tracing_file() function returns the full path of
the file with given name in the trace file system. The function
works only with files in the tracefs main directory, it is not
trace instance aware. It is recommended to use
tracefs_instance_get_file() and tracefs_instance_get_dir()
instead. The returned string must be freed with
tracefs_put_tracing_file().
The tracefs_put_tracing_file() function frees trace file name,
returned by tracefs_get_tracing_file().
The tracefs_tracing_dir() function returns the full path to the
trace file system. In the first function call, the mount point of
the tracing file system is located, cached and returned. It will
mount it, if it is not mounted. On any subsequent call the cached
path is returned. The return string must not be freed.
The tracefs_debug_dir() is similar to tracefs_tracing_dir() except
that it will return where the debugfs file system is mounted. If
it is not mounted it will try to mount it. The return string must
not be freed.
tracefs_tracing_dir_is_mounted() returns 1 if the tracing
directory is already mounted and 0 if it is not. If mount is true,
it will try to mount it if it is not, and returns 0 if it
succesfully mounted it and -1 if it did not. If path is set, it
will be assigned to the path where it mounted it. path is internal
and should not be freed.
The tracefs_set_tracing_dir() function returns 0 on success, -1
otherwise.
The tracefs_get_tracing_file() function returns a string or NULL
in case of an error. The returned string must be freed with
tracefs_put_tracing_file().
The tracefs_tracing_dir() function returns a constant string or
NULL in case of an error. The returned string must not be freed.
The tracefs_debug_dir() function returns a constant string or NULL
in case of an error. The returned string must not be freed.
The tracefs_tracing_dir_is_mounted() returns 1 if the tracing
directory is already mounted, 0 if it is not, and -1 on error.
#include <tracefs.h>
...
char *trace_on = tracefs_get_tracing_file("tracing_on");
if (trace_on) {
...
tracefs_put_tracing_file(trace_on);
}
...
const char *trace_dir = tracefs_tracing_dir();
tracefs.h
Header file to include in order to have access to the library APIs.
-ltracefs
Linker switch to add when building a program that uses the library.
libtracefs(3), libtraceevent(3), trace-cmd(1)
Steven Rostedt <rostedt@goodmis.org[1]>
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtracefs is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
Copyright (C) 2020 VMware, Inc. Free use of this software is
granted under the terms of the GNU Public License (GPL).
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
2. tz.stoyanov@gmail.com
mailto:tz.stoyanov@gmail.com
3. linux-trace-devel@vger.kernel.org
mailto:linux-trace-devel@vger.kernel.org
This page is part of the libtracefs (Linux kernel trace file
system library) project. Information about the project can be
found at ⟨https://www.trace-cmd.org/⟩. If you have a bug report
for this manual page, see ⟨https://www.trace-cmd.org/⟩. This page
was obtained from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-06-02.) 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
libtracefs 1.7.0 12/22/2023 LIBTRACEFS(3)
Pages that refer to this page: tracefs_event_get_file(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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