[PATCH 3/3] trace-cmd: Fix setting triggers to all events from given system

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

When running the "trace-cmd record -e (system) -R (trigger)" command for an event system, it fails with
"no such file or directory error". This use case is supposed to apply the given trigger to all events
from the system.

Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206737
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/trace-record.c | 99 +++++++++++++++++++++++++++--------------
 1 file changed, 65 insertions(+), 34 deletions(-)

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 7dbf599a..76305d1a 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2658,6 +2658,21 @@ static void set_max_graph_depth(struct buffer_instance *instance, char *max_grap
 		die("could not write to max_graph_depth");
 }
 
+static bool check_file_in_dir(char *dir, char *file)
+{
+	struct stat st;
+	char *path;
+	int ret;
+
+	ret = asprintf(&path, "%s/%s", dir, file);
+	if (ret < 0)
+		die("Failed to allocate id file path for %s/%s", dir, file);
+	ret = stat(path, &st);
+	free(path);
+	if (ret < 0 || S_ISDIR(st.st_mode))
+		return false;
+	return true;
+}
 
 /**
  * create_event - create and event descriptor
@@ -2703,14 +2718,19 @@ create_event(struct buffer_instance *instance, char *path, struct event_list *ol
 		free(p);
 
 	if (old_event->trigger) {
-		event->trigger = strdup(old_event->trigger);
-		ret = asprintf(&p, "%s/trigger", path_dirname);
-		if (ret < 0)
-			die("Failed to allocate trigger path for %s", path);
-		ret = stat(p, &st);
-		if (ret < 0)
-			die("trigger specified but not supported by this kernel");
-		event->trigger_file = p;
+		if (check_file_in_dir(path_dirname, "trigger")) {
+			event->trigger = strdup(old_event->trigger);
+			ret = asprintf(&p, "%s/trigger", path_dirname);
+			if (ret < 0)
+				die("Failed to allocate trigger path for %s", path);
+			event->trigger_file = p;
+		} else {
+			/* Check if this is event or system.
+			 * Systems do not have trigger files by design
+			 */
+			if (check_file_in_dir(path_dirname, "id"))
+				die("trigger specified but not supported by this kernel");
+		}
 	}
 
 	return event;
@@ -2815,14 +2835,29 @@ static int expand_event_files(struct buffer_instance *instance,
 	return save_event_tail == instance->event_next;
 }
 
+static int expand_events_all(struct buffer_instance *instance,
+			     char *system_name, char *event_name,
+			     struct event_list *event)
+{
+	char *name;
+	int ret;
+
+	ret = asprintf(&name, "%s/%s", system_name, event_name);
+	if (ret < 0)
+		die("Failed to allocate system/event for %s/%s",
+		     system_name, event_name);
+	ret = expand_event_files(instance, name, event);
+	free(name);
+
+	return ret;
+}
+
 static void expand_event(struct buffer_instance *instance, struct event_list *event)
 {
 	const char *name = event->event;
 	char *str;
 	char *ptr;
-	int len;
 	int ret;
-	int ret2;
 
 	/*
 	 * We allow the user to use "all" to enable all events.
@@ -2833,41 +2868,37 @@ static void expand_event(struct buffer_instance *instance, struct event_list *ev
 		return;
 	}
 
-	ptr = strchr(name, ':');
+	str = strdup(name);
+	if (!str)
+		die("Failed to allocate %s string", name);
 
+	ptr = strchr(str, ':');
 	if (ptr) {
-		len = ptr - name;
-		str = malloc(strlen(name) + 1); /* may add '*' */
-		if (!str)
-			die("Failed to allocate event for %s", name);
-		strcpy(str, name);
-		str[len] = '/';
+		*ptr = '\0';
 		ptr++;
-		if (!strlen(ptr)) {
-			str[len + 1] = '*';
-			str[len + 2] = '\0';
-		}
 
-		ret = expand_event_files(instance, str, event);
+		if (strlen(ptr))
+			ret = expand_events_all(instance, str, ptr, event);
+		else
+			ret = expand_events_all(instance, str, "*", event);
+
 		if (!ignore_event_not_found && ret)
 			die("No events enabled with %s", name);
-		free(str);
-		return;
+
+		goto out;
 	}
 
 	/* No ':' so enable all matching systems and events */
-	ret = expand_event_files(instance, name, event);
-
-	len = strlen(name) + strlen("*/") + 1;
-	str = malloc(len);
-	if (!str)
-		die("Failed to allocate event for %s", name);
-	snprintf(str, len, "*/%s", name);
-	ret2 = expand_event_files(instance, str, event);
-	free(str);
+	ret = expand_event_files(instance, str, event);
+	ret &= expand_events_all(instance, "*", str, event);
+	if (event->trigger)
+		ret &= expand_events_all(instance, str, "*", event);
 
-	if (!ignore_event_not_found && ret && ret2)
+	if (!ignore_event_not_found && ret)
 		die("No events enabled with %s", name);
+
+out:
+	free(str);
 }
 
 static void expand_event_instance(struct buffer_instance *instance)
-- 
2.25.1