|
HTML rendering created 2025-02-02 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. |
|
|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | COPYING | NOTES | COLOPHON |
|
|
|
LIBTRACEFS(3) libtracefs Manual LIBTRACEFS(3)
tracefs_local_events, tracefs_local_events_system,
tracefs_fill_local_events, tracefs_load_cmdlines,
tracefs_load_headers - Initialize a tep handler with trace events
from the local system.
#include <tracefs.h>
struct tep_handle *tracefs_local_events(const char *tracing_dir);
struct tep_handle *tracefs_local_events_system(const char *tracing_dir, const char * const *sys_names);
int tracefs_fill_local_events(const char *tracing_dir, struct tep_handle *tep, int *parsing_failures);
int tracefs_load_cmdlines(const char *tracing_dir, struct tep_handle *tep);
int tracefs_load_headers(const char *tracing_dir, struct tep_handle *tep);
Functions for initializing a tep handler with trace events from
the local system.
The tracefs_local_events() function allocates a new tep handler
and initializes it with events from all trace systems, located in
the given tracing_dir directory. This could be NULL or the
location of the tracefs mount point for the trace systems of the
local machine, or it may be a path to a copy of the tracefs
directory from another machine.
The tracefs_local_events_system() function allocates a new tep
handler and initializes it with events from specified trace
systems sys_names, located in the given tracing_dir directory.
This could be NULL or the location of the tracefs mount point for
the trace systems of the local machine, or it may be a path to a
copy of the tracefs directory from another machine. The sys_names
argument is an array of trace system names, that will be used for
tep handler initialization. The last element in that array must be
a NULL pointer.
The tracefs_fill_local_events() function initializes already
allocated tep handler with events from all trace systems, located
in the given tracing_dir directory. This could be NULL or the
location of the tracefs mount point for the trace systems of the
local machine, or it may be a path to a copy of the tracefs
directory from another machine. The tep argument must be a pointer
to already allocated tep handler, that is going to be initialized.
The parsing_failures argument could be NULL or a pointer to an
integer, where the number of failures while parsing the event
files are returned.
The above functions will also load the mappings between pids and
the process command line names. In some cases the tep handle is
created with one of the above before tracing begins. As the
mappings get updated during the trace, there may be a need to read
the mappings again after the trace. The tracefs_load_cmdlines()
does just that. The tracing_dir is the directory of the mount
point to load from, or NULL to use the mount point of the tracefs
file system.
The tracefs_load_headers() will reade the "header_page" of the
events directory that will update the tep handle with information
on how to parse the tracing ring buffer sub-buffer.
The tracefs_local_events() and tracefs_local_events_system()
functions return pointer to allocated and initialized tep handler,
or NULL in case of an error. The returned tep handler must be
freed with tep_free(3).
The tracefs_fill_local_events() function returns -1 in case of an
error or 0 otherwise.
The tracefs_load_cmdlines() function returns -1 in case of an
error, or 0 otherwise.
#include <tracefs.h>
struct tep_handle *tep;
...
tep = tracefs_local_events(NULL);
if (!tep) {
/* Failed to initialise tep handler with local events from top instance */
...
}
...
tep_free(tep);
...
const char *systems[] = {"ftrace", "irq", NULL};
tep = tracefs_local_events_system(NULL, systems);
if (!tep) {
/* Failed to initialise tep handler with local events from
* ftrace and irq systems in top instance.
*/
...
}
...
tep_free(tep);
...
int parsing_failures;
tep = tep_alloc();
if (!tep) {
/* Failed to allocate a tep handler */
...
}
if (tracefs_fill_local_events(NULL, tep, &parsing_failures) < 0) {
/* Failed to initialise tep handler with local events from top instance */
}
tracefs_load_cmdlines(NULL, tep);
...
tep_free(tep);
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
2025-02-02. (At that time, the date of the most recent commit
that was found in the repository was 2024-11-22.) 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 1.8.1 01/02/2025 LIBTRACEFS(3)
Pages that refer to this page: tracefs_hist_alloc(3), tracefs_iterate_raw_events(3), tracefs_synth_alloc(3)
|
HTML rendering created 2025-02-02 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. |
|