[PATCH v2 1/4] trace-cmd: Add parse error checking target

[Vaibhav Nagarnaik <vnagarnaik@google.com>]

Add another target 'check-events' which parses all the event formats and
returns whether there are any issues with the print format strings.

With an error in the format, the return value is 22 (EINVAL) and for
success, it is 0.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
---
Changelog v2-v1:
* Pass any parsing failures in pevent structure

 parse-events.h |    2 ++
 trace-cmd.c    |   25 +++++++++++++++++++++++++
 trace-usage.c  |    5 +++++
 trace-util.c   |   36 ++++++++++++++++++++++++++----------
 4 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/parse-events.h b/parse-events.h
index c32d715..f5cab15 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -402,6 +402,8 @@ struct pevent {
 	struct event_handler *handlers;
 	struct pevent_function_handler *func_handlers;
 
+	int parsing_failures;
+
 	/* cache */
 	struct event_format *last_event;
 };
diff --git a/trace-cmd.c b/trace-cmd.c
index bff5bbf..5cfd97f 100644
--- a/trace-cmd.c
+++ b/trace-cmd.c
@@ -158,6 +158,31 @@ int main (int argc, char **argv)
 	} else if (strcmp(argv[1], "stack") == 0) {
 		trace_stack(argc, argv);
 		exit(0);
+	} else if (strcmp(argv[1], "check-events") == 0) {
+		char *tracing;
+		int ret;
+		struct pevent *pevent = NULL;
+
+		tracing = tracecmd_find_tracing_dir();
+
+		if (!tracing) {
+			printf("Can not find or mount tracing directory!\n"
+				"Either tracing is not configured for this "
+				"kernel\n"
+				"or you do not have the proper permissions to "
+				"mount the directory");
+			exit(EINVAL);
+		}
+
+		ret = 0;
+		pevent = tracecmd_local_events(tracing);
+		if (!pevent)
+			exit(EINVAL);
+		if (pevent->parsing_failures)
+			ret = EINVAL;
+		pevent_free(pevent);
+		exit(ret);
+
 	} else if (strcmp(argv[1], "record") == 0 ||
 		   strcmp(argv[1], "start") == 0 ||
 		   strcmp(argv[1], "extract") == 0 ||
diff --git a/trace-usage.c b/trace-usage.c
index 39c8fc1..58ef167 100644
--- a/trace-usage.c
+++ b/trace-usage.c
@@ -150,6 +150,11 @@ static struct usage_help usage_help[] = {
 		"          --reset  reset the maximum stack found\n"
 	},
 	{
+		"check-events",
+		"parse trace event formats",
+		" %s check-format\n"
+	},
+	{
 		NULL, NULL, NULL
 	}
 };
diff --git a/trace-util.c b/trace-util.c
index 674f37e..01894f8 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -621,22 +621,22 @@ static int read_file(const char *file, char **buffer)
 	return len;
 }
 
-static void load_events(struct pevent *pevent, const char *system,
+static int load_events(struct pevent *pevent, const char *system,
 			const char *sys_dir)
 {
 	struct dirent *dent;
 	struct stat st;
 	DIR *dir;
 	int len = 0;
-	int ret;
+	int ret = 0, failure = 0;
 
 	ret = stat(sys_dir, &st);
 	if (ret < 0 || !S_ISDIR(st.st_mode))
-		return;
+		return EINVAL;
 
 	dir = opendir(sys_dir);
 	if (!dir)
-		return;
+		return errno;
 
 	while ((dent = readdir(dir))) {
 		const char *name = dent->d_name;
@@ -662,15 +662,18 @@ static void load_events(struct pevent *pevent, const char *system,
 		if (len < 0)
 			goto free_format;
 
-		pevent_parse_event(pevent, buf, len, system);
+		ret = pevent_parse_event(pevent, buf, len, system);
 		free(buf);
  free_format:
 		free(format);
  free_event:
 		free(event);
+		if (ret)
+			failure = ret;
 	}
 
 	closedir(dir);
+	return failure;
 }
 
 static int read_header(struct pevent *pevent, const char *events_dir)
@@ -715,7 +718,7 @@ struct pevent *tracecmd_local_events(const char *tracing_dir)
 	char *events_dir;
 	struct stat st;
 	DIR *dir;
-	int ret;
+	int ret, failure = 0;
 
 	if (!tracing_dir)
 		return NULL;
@@ -725,21 +728,28 @@ struct pevent *tracecmd_local_events(const char *tracing_dir)
 		return NULL;
 
 	ret = stat(events_dir, &st);
-	if (ret < 0 || !S_ISDIR(st.st_mode))
+	if (ret < 0 || !S_ISDIR(st.st_mode)) {
+		failure = 1;
 		goto out_free;
+	}
 
 	dir = opendir(events_dir);
-	if (!dir)
+	if (!dir) {
+		failure = 1;
 		goto out_free;
+	}
 
 	pevent = pevent_alloc();
-	if (!pevent)
+	if (!pevent) {
+		failure = 1;
 		goto out_free;
+	}
 
 	ret = read_header(pevent, events_dir);
 	if (ret < 0) {
 		pevent_free(pevent);
 		pevent = NULL;
+		failure = 1;
 		goto out_free;
 	}
 
@@ -758,9 +768,12 @@ struct pevent *tracecmd_local_events(const char *tracing_dir)
 			continue;
 		}
 
-		load_events(pevent, name, sys);
+		ret = load_events(pevent, name, sys);
 
 		free(sys);
+
+		if (ret)
+			failure = 1;
 	}
 
 	closedir(dir);
@@ -768,6 +781,9 @@ struct pevent *tracecmd_local_events(const char *tracing_dir)
  out_free:
 	free(events_dir);
 
+	if (pevent)
+		pevent->parsing_failures = failure;
+
 	return pevent;
 }
 
-- 
1.7.3.1