New man pages with documentation about:
tracefs_trace_is_on();
tracefs_trace_on();
tracefs_trace_off();
tracefs_trace_on_fd();
tracefs_trace_off_fd();
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
Documentation/libtracefs-traceon.txt | 151 +++++++++++++++++++++++++++
Documentation/libtracefs.txt | 6 ++
2 files changed, 157 insertions(+)
create mode 100644 Documentation/libtracefs-traceon.txt
diff --git a/Documentation/libtracefs-traceon.txt b/Documentation/libtracefs-traceon.txt
new file mode 100644
index 0000000..d7fc239
--- /dev/null
+++ b/Documentation/libtracefs-traceon.txt
@@ -0,0 +1,151 @@
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_trace_is_on, tracefs_trace_on, tracefs_trace_off, tracefs_trace_on_get_fd,
+tracefs_trace_on_fd, tracefs_trace_off_fd - Functions to enable or disable tracing.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+int *tracefs_trace_is_on*(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_trace_on*(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_trace_off*(struct tracefs_instance pass:[*]_instance_);
+int _tracefs_trace_on_get_fd_(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_trace_on_fd*(int _fd_);
+int *tracefs_trace_off_fd*(int _fd_);
+--
+
+DESCRIPTION
+-----------
+This set of functions can be used to check, enable or disable writing to the ring buffer in
+the given trace instance. The tracing is enabled when writing to the ring buffer is enabled.
+
+The _tracefs_trace_is_on()_ function checks if tracing is enabled for the given _instance_. If
+_instance_ is NULL, the top instance is used.
+
+The _tracefs_trace_on()_ and _tracefs_trace_off()_ functions set the tracing in the _instance_
+to enable or disable state. If _instance_ is NULL, the top instance is used.
+
+The _tracefs_trace_on_get_fd()_ function returns a file deascriptor to the "tracing_on" file from
+the given _instance_. If _instance_ is NULL, the top trace instance is used. The returned descriptor
+can be used for fast enabling or disabling the tracing of the instance.
+
+The _tracefs_trace_on_fd()_ and _tracefs_trace_off_fd()_ functions set the tracing state to enable
+or disable using the given _fd_. This file descriptor must be opened for writing with
+*tracefs_trace_on_get_fd*(3) of the desired trace instance. These functions are faster than
+*tracefs_trace_on* and *tracefs_trace_off*.
+
+RETURN VALUE
+------------
+The _tracefs_trace_is_on()_ function returns 0 if tracing is disable, 1 if it is enabled or
+-1 in case of an error.
+
+The _tracefs_trace_on_get_fd()_ function returns a file descriptor to "tracing_on"
+file for reading and writing, which must be closed wuth close(). In case of an error -1 is returned.
+
+The _tracefs_trace_on()_, _tracefs_trace_off()_, _tracefs_trace_on_fd()_ and
+_tracefs_trace_off_fd()_ functions return -1 in case of an error or 0 otherwise.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <tracefs.h>
+
+ int ret;
+
+ ret = tracefs_trace_is_on(NULL);
+ if (ret == 0) {
+ /* Tracing is disabled in the top instance */
+ } else if (ret == 1) {"
+ /* Tracing is enabled in the top instance */
+ } else {
+ /* Error getting tracing state of the top instance */
+ }
+
+ ...
+
+ if (!tracefs_trace_on(NULL)) {
+ /* Enabled tracing in the top instance */
+
+ ...
+
+ if (!tracefs_trace_off(NULL)) {
+ /* Disabled tracing in the top instance */
+ } else {
+ /* Error disabling tracing in the top instance */
+ }
+ } else {
+ /* Error enabling tracing in the top instance */
+ }
+
+ ...
+
+ int fd = tracefs_trace_on_get_fd(NULL);
+
+ if (fd < 0) {
+ /* Error opening tracing_on file */
+ }
+ ...
+ if (!tracefs_trace_on_fd(fd)) {
+ /* Enabled tracing in the top instance */
+
+ ...
+
+ if (!tracefs_trace_off_fd(fd)) {
+ /* Disabled tracing in the top instance */
+ } else {
+ /* Error disabling tracing in the top instance */
+ }
+ } else {
+ /* Error enabling tracing in the top instance */
+ }
+
+ ...
+
+ close(fd);
+--
+FILES
+-----
+[verse]
+--
+*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.
+--
+
+SEE ALSO
+--------
+_libtracefs(3)_,
+_libtraceevent(3)_,
+_trace-cmd(1)_
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@xxxxxxxxxxx>
+*Tzvetomir Stoyanov* <tz.stoyanov@xxxxxxxxx>
+--
+REPORTING BUGS
+--------------
+Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
+
+COPYING
+-------
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt
index 0350416..cea21fe 100644
--- a/Documentation/libtracefs.txt
+++ b/Documentation/libtracefs.txt
@@ -45,6 +45,12 @@ Trace helper functions:
void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
char pass:[*]pass:[*]*tracefs_tracers*(const char pass:[*]_tracing_dir_);
char pass:[*]*tracefs_get_clock*(struct tracefs_instance pass:[*]_instance_);
+ int *tracefs_trace_is_on*(struct tracefs_instance pass:[*]_instance_);
+ int *tracefs_trace_on*(struct tracefs_instance pass:[*]_instance_);
+ int *tracefs_trace_off*(struct tracefs_instance pass:[*]_instance_);
+ int _tracefs_trace_on_get_fd_(struct tracefs_instance pass:[*]_instance_);
+ int *tracefs_trace_on_fd*(int _fd_);
+ int *tracefs_trace_off_fd*(int _fd_);
--
DESCRIPTION
--
2.29.2
|