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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | NOTES | COLOPHON |
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LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)
tep_parse_saved_cmdlines, tep_parse_printk_formats,
tep_parse_kallsyms - Parsing functions to load mappings
#include <event-parse.h>
int tep_parse_saved_cmdlines(struct tep_handle *tep, const char *buf);
int tep_parse_printk_formats(struct tep_handle *tep, const char *buf);
int tep_parse_kallsyms(struct tep_handle *tep, const char *buf);
tep_parse_saved_cmdlines() is a helper function to parse content
in the tracefs file system of the "saved_cmdlines" file (stored in
a string buffer passed in by buf) and loads the mapping of the
process IDs (pid) to the comm names in the tep handler. The events
store the pid and this is used to be able to show the process
names associated to those process ids. It parses the string buf
that holds the content of saved_cmdlines and ends with a nul
character (\0).
tep_parse_printk_formats() is a helper function to parse content
in the tracefs file system of the "printk_formats" file (stored in
a string buffer passed in by buf) and loads the mapping of
addresses of strings that may be referenced by events. Events only
store the address of constant strings in the kernel, and the
mapping of their address to the string is exported to user space
in the printk_formats file. It parses the string buf that holds
the content of printk_formats and ends with a nul character (\0).
tep_parse_kallsyms() is a helper function to parse the Linux
kernel /proc/kallsyms format (stored in a string buffer passed in
by buf) and load the functions into the tep handler such that
function IP addresses can be mapped to their name when parsing
events with %pS in the print format field. It parses the string
buf that holds the content of /proc/kallsyms and ends with a nul
character (\0).
The tep_parse_saved_cmdlines() function returns 0 in case of
success, or -1 in case of an error.
The tep_parse_printk_formats() function returns 0 in case of
success, or -1 in case of an error.
The tep_parse_kallsyms() function returns 0 in case of success, or
-1 in case of an error.
...
#include <event-parse.h>
#include <tracefs.h>
#include <stdlib.h>
int load_cmdlines(struct tep_handle *tep)
{
char *buf = NULL;
int r;
buf = tracefs_instance_file_read(NULL, "saved_cmdlines", NULL);
if (!buf)
return -1;
r = tep_parse_saved_cmdlines(tep, buf);
free(buf);
return r;
}
int load_print_strings(struct tep_handle *tep)
{
char *buf = NULL;
int r;
buf = tracefs_instance_file_read(NULL, "printk_formats", NULL);
if (!buf)
return -1;
r = tep_parse_printk_formats(tep, buf);
free(buf);
return r;
}
int load_kallsyms(struct tep_handle *tep)
{
char *line = NULL;
char *buf = NULL;
size_t sz = 0;
FILE *fp;
int len = 0;
int r;
fp = fopen("/proc/kallsyms", "r");
while ((r = getline(&line, &sz, fp)) >= 0) {
buf = realloc(buf, len + r + 1);
memcpy(buf + len, line, r);
len += r;
}
free(line);
fclose(fp);
if (!buf)
return -1;
buf[len] = 0;
r = tep_parse_kallsyms(tep, buf);
free(buf);
return r;
}
...
event-parse.h
Header file to include in order to have access to the library APIs.
-ltraceevent
Linker switch to add when building a program that uses the library.
libtraceevent(3), trace-cmd(1), tep_register_comm(3),
tep_register_function(3), tep_register_print_string(3)
Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, coauthor of libtraceevent.
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtraceevent is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
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 libtraceevent (Linux kernel trace event
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/libtraceevent.git⟩
on 2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-05-30.) 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
libtraceevent 1.7.3 09/24/2023 LIBTRACEEVENT(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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