diff mbox series

[1/7] trace-cmd: Implemented new lib API: tracecmd_local_events_system()

Message ID 20190116191838.32127-2-tstoyanov@vmware.com (mailing list archive)
State Superseded
Headers show
Series trace-cmd [POC]: Timestamps sync using PTP-like algorithm, relying on vsock events. | expand

Commit Message

Tzvetomir Stoyanov Jan. 16, 2019, 7:18 p.m. UTC 
The new tracecmd lib API tracecmd_local_events_system() creates
a tep handler and initializes it with the events of the
specified subsystem.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 include/trace-cmd/trace-cmd.h |  2 +
 lib/trace-cmd/trace-util.c    | 89 ++++++++++++++++++++++-------------
 2 files changed, 59 insertions(+), 32 deletions(-)

Comments

Steven Rostedt Jan. 21, 2019, 9:02 a.m. UTC | #1 
On Wed, 16 Jan 2019 21:18:32 +0200
Tzvetomir Stoyanov <tstoyanov@vmware.com> wrote:

> +static int tracecmd_fill_local_events_system(const char *tracing_dir,
> +					     struct tep_handle *pevent,
> +					     char *sys_name)
>  {
>  	struct dirent *dent;
>  	char *events_dir;
> @@ -1189,7 +1161,8 @@ int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *peven
>  		if (strcmp(name, ".") == 0 ||
>  		    strcmp(name, "..") == 0)
>  			continue;
> -
> +		if (sys_name && strcmp(name, sys_name))

Small nit. Please compare as: strcmp(name, sys_name) != 0

This to make it look like it is not equal. One of the flaws of the
"strcmp" is that a match is false and a non match is true, which makes
it likely to be done wrong :-p

If you noticed, the strcmp() in the previous if uses "== 0" as a way to
say "this is true on match"


> +			continue;
>  		sys = append_file(events_dir, name);
>  		ret = stat(sys, &st);
>  		if (ret < 0 || !S_ISDIR(st.st_mode)) {
> @@ -1217,6 +1190,58 @@ int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *peven
>  	return ret;
>  }
>  
> +/**
> + * tracecmd_local_events_system - create a tep from the
> + * events of the specified subsystem.

Keep the above on one line, even though it breaks the 80 character
limit.

-- Steve

> + *
> + * @tracing_dir: The directory that contains the events.
> + * @sys_name: Name of the subsystem, to load events from
> + *
> + * Returns a tep structure that contains the tep local to
> + * the system.
> + */
> +struct tep_handle *tracecmd_local_events_system(const char *tracing_dir,
> +						char *sys_name)
> +{
> +	struct tep_handle *tep = NULL;
> +
> +	tep = tep_alloc();
> +	if (!tep)
> +		return NULL;
> +
> +	if (tracecmd_fill_local_events_system(tracing_dir, tep, sys_name)) {
> +		tep_free(tep);
> +		tep = NULL;
> +	}
> +
> +	return tep;
> +}
>
diff mbox series

Patch

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 238e16b..c79fc63 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -32,6 +32,8 @@  void tracecmd_unload_plugins(struct tep_plugin_list *list, struct tep_handle *pe
 char **tracecmd_event_systems(const char *tracing_dir);
 char **tracecmd_system_events(const char *tracing_dir, const char *system);
 struct tep_handle *tracecmd_local_events(const char *tracing_dir);
+struct tep_handle *tracecmd_local_events_system(const char *tracing_dir,
+						char *sys_name);
 int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *pevent);
 char **tracecmd_local_plugins(const char *tracing_dir);
 
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index b5aea39..706aab3 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -1119,37 +1119,9 @@  static int read_header(struct tep_handle *pevent, const char *events_dir)
 	return ret;
 }
 
-/**
- * tracecmd_local_events - create a pevent from the events on system
- * @tracing_dir: The directory that contains the events.
- *
- * Returns a pevent structure that contains the pevents local to
- * the system.
- */
-struct tep_handle *tracecmd_local_events(const char *tracing_dir)
-{
-	struct tep_handle *pevent = NULL;
-
-	pevent = tep_alloc();
-	if (!pevent)
-		return NULL;
-
-	if (tracecmd_fill_local_events(tracing_dir, pevent)) {
-		tep_free(pevent);
-		pevent = NULL;
-	}
-
-	return pevent;
-}
-
-/**
- * tracecmd_fill_local_events - Fill a pevent with the events on system
- * @tracing_dir: The directory that contains the events.
- * @pevent: Allocated pevent which will be filled
- *
- * Returns whether the operation succeeded
- */
-int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *pevent)
+static int tracecmd_fill_local_events_system(const char *tracing_dir,
+					     struct tep_handle *pevent,
+					     char *sys_name)
 {
 	struct dirent *dent;
 	char *events_dir;
@@ -1189,7 +1161,8 @@  int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *peven
 		if (strcmp(name, ".") == 0 ||
 		    strcmp(name, "..") == 0)
 			continue;
-
+		if (sys_name && strcmp(name, sys_name))
+			continue;
 		sys = append_file(events_dir, name);
 		ret = stat(sys, &st);
 		if (ret < 0 || !S_ISDIR(st.st_mode)) {
@@ -1217,6 +1190,58 @@  int tracecmd_fill_local_events(const char *tracing_dir, struct tep_handle *peven
 	return ret;
 }
 
+/**
+ * tracecmd_local_events_system - create a tep from the
+ * events of the specified subsystem.
+ *
+ * @tracing_dir: The directory that contains the events.
+ * @sys_name: Name of the subsystem, to load events from
+ *
+ * Returns a tep structure that contains the tep local to
+ * the system.
+ */
+struct tep_handle *tracecmd_local_events_system(const char *tracing_dir,
+						char *sys_name)
+{
+	struct tep_handle *tep = NULL;
+
+	tep = tep_alloc();
+	if (!tep)
+		return NULL;
+
+	if (tracecmd_fill_local_events_system(tracing_dir, tep, sys_name)) {
+		tep_free(tep);
+		tep = NULL;
+	}
+
+	return tep;
+}
+
+/**
+ * tracecmd_local_events - create a pevent from the events on system
+ * @tracing_dir: The directory that contains the events.
+ *
+ * Returns a pevent structure that contains the pevents local to
+ * the system.
+ */
+struct tep_handle *tracecmd_local_events(const char *tracing_dir)
+{
+	return tracecmd_local_events_system(tracing_dir, NULL);
+}
+
+/**
+ * tracecmd_fill_local_events - Fill a pevent with the events on system
+ * @tracing_dir: The directory that contains the events.
+ * @pevent: Allocated pevent which will be filled
+ *
+ * Returns whether the operation succeeded
+ */
+int tracecmd_fill_local_events(const char *tracing_dir,
+			       struct tep_handle *pevent)
+{
+	return tracecmd_fill_local_events_system(tracing_dir, pevent, NULL);
+}
+
 /**
  * tracecmd_local_plugins - returns an array of available tracer plugins
  * @tracing_dir: The directory that contains the tracing directory