[PATCH v3 0/4] trace-cmd list: Include ftrace in event listings

[PATCH v3 0/4] trace-cmd list: Include ftrace in event listings

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

I'm constantly needing to look at the event formats of ftrace events
(like the function event or print event), but trace-cmd list does not
include them, as they can not be enabled by trace-cmd record/start.

By default, trace-cmd list -e, wont show ftrace events, but if a regex
is added to the search: trace-cmd list -e print, then it will now list
those events in ftrace. This is useful for:

 # trace-cmd list -e ftrace:function -F
system: ftrace
name: function
ID: 1
format:
        field:unsigned short common_type;       offset:0;       size:2; signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;

        field:unsigned long ip; offset:8;       size:8; signed:0;
        field:unsigned long parent_ip;  offset:16;      size:8; signed:0;

Changes since v2:

 - Fixed cover letter subject and body, as v2 referenced listing of options?
   https://lore.kernel.org/linux-trace-devel/20210422211803.862397-1-rostedt@goodmis.org/

 - Broke up patch: https://lore.kernel.org/linux-trace-devel/20210422211803.862397-4-rostedt@goodmis.org/
   To separate out the adding of the helper function "match_system_events()"
   from the functional change of listing ftrace events.

 - The diff of this patch set compared to v2 is the same (no functional changes).


Steven Rostedt (VMware) (4):
  trace-cmd list: Add --full to show print fmt of an event
  trace-cmd list: Use tracefs to help find events for -e
  trace-cmd list: Add match_system_events() helper function
  trace-cmd list: Add ftrace events to listing of events

 Documentation/trace-cmd/trace-cmd-list.1.txt |   5 +-
 tracecmd/trace-list.c                        | 179 +++++++++++++++++--
 tracecmd/trace-usage.c                       |   1 +
 3 files changed, 168 insertions(+), 17 deletions(-)

-- 
2.29.2

[PATCH v3 1/4] trace-cmd list: Add --full to show print fmt of an event

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

There's several times I want to see the print fmt from the event's format
file, and there's no way to do that with trace-cmd list -e. Add a --full
option to display the entire format file of an event, including the print
fmt, which can be useful as well.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/trace-cmd/trace-cmd-list.1.txt |  5 ++-
 tracecmd/trace-list.c                        | 37 ++++++++++++--------
 tracecmd/trace-usage.c                       |  1 +
 3 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/Documentation/trace-cmd/trace-cmd-list.1.txt b/Documentation/trace-cmd/trace-cmd-list.1.txt
index 0ad62643..a5c6b16c 100644
--- a/Documentation/trace-cmd/trace-cmd-list.1.txt
+++ b/Documentation/trace-cmd/trace-cmd-list.1.txt
@@ -26,7 +26,10 @@ OPTIONS
     trace-cmd list -e '^sys.*'
 
 *-F*::
-    Used with *-e* 'regex' to show those events formats.
+    Used with *-e* 'regex' to show the fields of the event.
+
+*--full*::
+    Used with *-F* which will show the "print fmt" of the event along with the fields.
 
 *-l*::
     Used with *-e* 'regex' to show those events filters.
diff --git a/tracecmd/trace-list.c b/tracecmd/trace-list.c
index 63216b43..fb62b754 100644
--- a/tracecmd/trace-list.c
+++ b/tracecmd/trace-list.c
@@ -44,6 +44,7 @@ enum {
 	SHOW_EVENT_FORMAT		= 1 << 0,
 	SHOW_EVENT_FILTER		= 1 << 1,
 	SHOW_EVENT_TRIGGER		= 1 << 2,
+	SHOW_EVENT_FULL			= 1 << 3,
 };
 
 
@@ -56,10 +57,10 @@ void show_file(const char *name)
 	tracefs_put_tracing_file(path);
 }
 
-typedef int (*process_file_func)(char *buf, int len);
+typedef int (*process_file_func)(char *buf, int len, int flags);
 
 static void process_file_re(process_file_func func,
-			    const char *name, const char *re)
+			    const char *name, const char *re, int flags)
 {
 	regex_t reg;
 	char *path;
@@ -97,7 +98,7 @@ static void process_file_re(process_file_func func,
 	do {
 		n = getline(&buf, &l, fp);
 		if (n > 0 && regexec(&reg, buf, 0, NULL, 0) == 0)
-			func(buf, n);
+			func(buf, n, flags);
 	} while (n > 0);
 	free(buf);
 	fclose(fp);
@@ -105,14 +106,14 @@ static void process_file_re(process_file_func func,
 	regfree(&reg);
 }
 
-static int show_file_write(char *buf, int len)
+static int show_file_write(char *buf, int len, int flags)
 {
 	return fwrite(buf, 1, len, stdout);
 }
 
 static void show_file_re(const char *name, const char *re)
 {
-	process_file_re(show_file_write, name, re);
+	process_file_re(show_file_write, name, re, 0);
 }
 
 static char *get_event_file(const char *type, char *buf, int len)
@@ -144,7 +145,7 @@ static char *get_event_file(const char *type, char *buf, int len)
 	return file;
 }
 
-static int event_filter_write(char *buf, int len)
+static int event_filter_write(char *buf, int len, int flags)
 {
 	char *file;
 
@@ -161,7 +162,7 @@ static int event_filter_write(char *buf, int len)
 	return 0;
 }
 
-static int event_trigger_write(char *buf, int len)
+static int event_trigger_write(char *buf, int len, int flags)
 {
 	char *file;
 
@@ -178,14 +179,17 @@ static int event_trigger_write(char *buf, int len)
 	return 0;
 }
 
-static int event_format_write(char *fbuf, int len)
+static int event_format_write(char *fbuf, int len, int flags)
 {
 	char *file = get_event_file("format", fbuf, len);
 	char *buf = NULL;
 	size_t l;
 	FILE *fp;
+	bool full;
 	int n;
 
+	full = flags & SHOW_EVENT_FULL;
+
 	/* The get_event_file() crops system in fbuf */
 	printf("system: %s\n", fbuf);
 
@@ -198,7 +202,7 @@ static int event_format_write(char *fbuf, int len)
 	do {
 		n = getline(&buf, &l, fp);
 		if (n > 0) {
-			if (strncmp(buf, "print fmt", 9) == 0)
+			if (!full && strncmp(buf, "print fmt", 9) == 0)
 				break;
 			fwrite(buf, 1, n, stdout);
 		}
@@ -213,19 +217,19 @@ static int event_format_write(char *fbuf, int len)
 
 static void show_event_filter_re(const char *re)
 {
-	process_file_re(event_filter_write, "available_events", re);
+	process_file_re(event_filter_write, "available_events", re, 0);
 }
 
 
 static void show_event_trigger_re(const char *re)
 {
-	process_file_re(event_trigger_write, "available_events", re);
+	process_file_re(event_trigger_write, "available_events", re, 0);
 }
 
 
-static void show_event_format_re(const char *re)
+static void show_event_format_re(const char *re, int flags)
 {
-	process_file_re(event_format_write, "available_events", re);
+	process_file_re(event_format_write, "available_events", re, flags);
 }
 
 
@@ -236,7 +240,7 @@ static void show_events(const char *eventre, int flags)
 
 	if (eventre) {
 		if (flags & SHOW_EVENT_FORMAT)
-			show_event_format_re(eventre);
+			show_event_format_re(eventre, flags);
 
 		else if (flags & SHOW_EVENT_FILTER)
 			show_event_filter_re(eventre);
@@ -405,7 +409,6 @@ static void show_plugins(void)
 	tep_free(pevent);
 }
 
-
 void trace_list(int argc, char **argv)
 {
 	int events = 0;
@@ -488,6 +491,10 @@ void trace_list(int argc, char **argv)
 					tracecmd_set_debug(true);
 					break;
 				}
+				if (strcmp(argv[i], "--full") == 0) {
+					flags |= SHOW_EVENT_FULL;
+					break;
+				}
 				fprintf(stderr, "list: invalid option -- '%s'\n",
 					argv[i]);
 			default:
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 98247074..7b0d01d8 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -319,6 +319,7 @@ static struct usage_help usage_help[] = {
 		" %s list [-e [regex]][-t][-o][-f [regex]]\n"
 		"          -e list available events\n"
 		"            -F show event format\n"
+		"            --full show the print fmt with -F\n"
 		"            -R show event triggers\n"
 		"            -l show event filters\n"
 		"          -t list available tracers\n"
-- 
2.29.2

[PATCH v3 2/4] trace-cmd list: Use tracefs to help find events for -e

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

When the user specifies -e and wants to search for events, use the tracefs
helper functions tracefs_event_systems() and tracefs_system_events() to
find the matching events.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tracecmd/trace-list.c | 135 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 131 insertions(+), 4 deletions(-)

diff --git a/tracecmd/trace-list.c b/tracecmd/trace-list.c
index fb62b754..a0d743fb 100644
--- a/tracecmd/trace-list.c
+++ b/tracecmd/trace-list.c
@@ -106,6 +106,123 @@ static void process_file_re(process_file_func func,
 	regfree(&reg);
 }
 
+static void show_event(process_file_func func, const char *system,
+		       const char *event, int flags)
+{
+	char *buf;
+	int ret;
+
+	ret = asprintf(&buf, "%s:%s", system, event);
+	if (ret < 0)
+		die("Can not allocate event");
+	func(buf, strlen(buf), flags);
+	free(buf);
+}
+
+static void show_system(process_file_func func, const char *system, int flags)
+{
+	char **events;
+	int e;
+
+	events = tracefs_system_events(NULL, system);
+	if (!events) /* die? */
+		return;
+
+	for (e = 0; events[e]; e++)
+		show_event(func, system, events[e], flags);
+}
+
+static void show_event_systems(process_file_func func, char **systems, int flags)
+{
+	int s;
+
+	for (s = 0; systems[s]; s++)
+		show_system(func, systems[s], flags);
+}
+
+
+static void process_events(process_file_func func, const char *re, int flags)
+{
+	regex_t system_reg;
+	regex_t event_reg;
+	char *str;
+	size_t l = strlen(re);
+	bool just_systems = true;
+	char **systems;
+	char **events;
+	char *system;
+	char *event;
+	int s, e;
+
+	systems = tracefs_event_systems(NULL);
+	if (!systems)
+		return process_file_re(func, "available_events", re, flags);
+
+	if (!re || l == 0) {
+		show_event_systems(func, systems, flags);
+		return;
+	}
+
+	str = strdup(re);
+	if (!str)
+		die("Can not allocate momory for regex");
+
+	system = strtok(str, ":");
+	event = strtok(NULL, "");
+
+	if (regcomp(&system_reg, system, REG_ICASE|REG_NOSUB))
+		die("invalid regex '%s'", system);
+
+	if (event) {
+		if (regcomp(&event_reg, event, REG_ICASE|REG_NOSUB))
+			die("invalid regex '%s'", event);
+	} else {
+		/*
+		 * If the regex ends with ":", then event would be null,
+		 * but we do not want to match events.
+		 */
+		if (re[l-1] != ':')
+			just_systems = false;
+	}
+	free(str);
+
+	for (s = 0; systems[s]; s++) {
+
+		if (regexec(&system_reg, systems[s], 0, NULL, 0) == 0) {
+			if (!event) {
+				show_system(func, systems[s], flags);
+				continue;
+			}
+			events = tracefs_system_events(NULL, systems[s]);
+			if (!events) /* die? */
+				continue;
+			for (e = 0; events[e]; e++) {
+				if (regexec(&event_reg, events[e], 0, NULL, 0) == 0)
+					show_event(func, systems[s], events[e], flags);
+			}
+			tracefs_list_free(events);
+			continue;
+		}
+		if (just_systems)
+			continue;
+
+		events = tracefs_system_events(NULL, systems[s]);
+		if (!events) /* die? */
+			continue;
+
+		for (e = 0; events[e]; e++) {
+			if (regexec(&system_reg, events[e], 0, NULL, 0) == 0)
+				show_event(func, systems[s], events[e], flags);
+		}
+		tracefs_list_free(events);
+	}
+	tracefs_list_free(systems);
+
+	regfree(&system_reg);
+	if (event)
+		regfree(&event_reg);
+}
+
 static int show_file_write(char *buf, int len, int flags)
 {
 	return fwrite(buf, 1, len, stdout);
@@ -214,24 +331,34 @@ static int event_format_write(char *fbuf, int len, int flags)
 	return 0;
 }
 
+static int event_name(char *buf, int len, int flags)
+{
+	printf("%s\n", buf);
+
+	return 0;
+}
 
 static void show_event_filter_re(const char *re)
 {
-	process_file_re(event_filter_write, "available_events", re, 0);
+	process_events(event_filter_write, re, 0);
 }
 
 
 static void show_event_trigger_re(const char *re)
 {
-	process_file_re(event_trigger_write, "available_events", re, 0);
+	process_events(event_trigger_write, re, 0);
 }
 
 
 static void show_event_format_re(const char *re, int flags)
 {
-	process_file_re(event_format_write, "available_events", re, flags);
+	process_events(event_format_write, re, flags);
 }
 
+static void show_event_names_re(const char *re)
+{
+	process_events(event_name, re, 0);
+}
 
 static void show_events(const char *eventre, int flags)
 {
@@ -248,7 +375,7 @@ static void show_events(const char *eventre, int flags)
 		else if (flags & SHOW_EVENT_TRIGGER)
 			show_event_trigger_re(eventre);
 		else
-			show_file_re("available_events", eventre);
+			show_event_names_re(eventre);
 	} else
 		show_file("available_events");
 }
-- 
2.29.2

[PATCH v3 3/4] trace-cmd list: Add match_system_events() helper function

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Remove the duplicate code that matches all events for a given system and
replace it with a helper function called match_system_events().

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tracecmd/trace-list.c | 37 ++++++++++++++++++-------------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/tracecmd/trace-list.c b/tracecmd/trace-list.c
index a0d743fb..1b32af17 100644
--- a/tracecmd/trace-list.c
+++ b/tracecmd/trace-list.c
@@ -140,6 +140,21 @@ static void show_event_systems(process_file_func func, char **systems, int flags
 		show_system(func, systems[s], flags);
 }
 
+static void match_system_events(process_file_func func, const char *system,
+				regex_t *reg, int flags)
+{
+	char **events;
+	int e;
+
+	events = tracefs_system_events(NULL, system);
+	if (!events) /* die? */
+		return;
+	for (e = 0; events[e]; e++) {
+		if (regexec(reg, events[e], 0, NULL, 0) == 0)
+			show_event(func, system, events[e], flags);
+	}
+	tracefs_list_free(events);
+}
 
 static void process_events(process_file_func func, const char *re, int flags)
 {
@@ -149,10 +164,9 @@ static void process_events(process_file_func func, const char *re, int flags)
 	size_t l = strlen(re);
 	bool just_systems = true;
 	char **systems;
-	char **events;
 	char *system;
 	char *event;
-	int s, e;
+	int s;
 
 	systems = tracefs_event_systems(NULL);
 	if (!systems)
@@ -193,28 +207,13 @@ static void process_events(process_file_func func, const char *re, int flags)
 				show_system(func, systems[s], flags);
 				continue;
 			}
-			events = tracefs_system_events(NULL, systems[s]);
-			if (!events) /* die? */
-				continue;
-			for (e = 0; events[e]; e++) {
-				if (regexec(&event_reg, events[e], 0, NULL, 0) == 0)
-					show_event(func, systems[s], events[e], flags);
-			}
-			tracefs_list_free(events);
+			match_system_events(func, systems[s], &event_reg, flags);
 			continue;
 		}
 		if (just_systems)
 			continue;
 
-		events = tracefs_system_events(NULL, systems[s]);
-		if (!events) /* die? */
-			continue;
-
-		for (e = 0; events[e]; e++) {
-			if (regexec(&system_reg, events[e], 0, NULL, 0) == 0)
-				show_event(func, systems[s], events[e], flags);
-		}
-		tracefs_list_free(events);
+		match_system_events(func, systems[s], &system_reg, flags);
 	}
 	tracefs_list_free(systems);
 
-- 
2.29.2

[PATCH v3 4/4] trace-cmd list: Add ftrace events to listing of events

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

If a search of events is done with trace-cmd list -e, check if any matches
the ftrace events. This is useful to get the fields and print fmt of the
events under the ftrace system.

Note, just "trace-cmd list -e" will still not list ftrace events by
default.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tracecmd/trace-list.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tracecmd/trace-list.c b/tracecmd/trace-list.c
index 1b32af17..d060c810 100644
--- a/tracecmd/trace-list.c
+++ b/tracecmd/trace-list.c
@@ -158,6 +158,7 @@ static void match_system_events(process_file_func func, const char *system,
 
 static void process_events(process_file_func func, const char *re, int flags)
 {
+	const char *ftrace = "ftrace";
 	regex_t system_reg;
 	regex_t event_reg;
 	char *str;
@@ -200,6 +201,19 @@ static void process_events(process_file_func func, const char *re, int flags)
 	}
 	free(str);
 
+	/*
+	 * See if this matches the special ftrace system, as ftrace is not included
+	 * in the systems list, but can get events from tracefs_system_events().
+	 */
+	if (regexec(&system_reg, ftrace, 0, NULL, 0) == 0) {
+		if (!event)
+			show_system(func, ftrace, flags);
+		else
+			match_system_events(func, ftrace, &event_reg, flags);
+	} else if (!just_systems) {
+		match_system_events(func, ftrace, &system_reg, flags);
+	}
+
 	for (s = 0; systems[s]; s++) {
 
 		if (regexec(&system_reg, systems[s], 0, NULL, 0) == 0) {
-- 
2.29.2