[PATCH 21/23] perf util: Add more debug message on failure path

[Arnaldo Carvalho de Melo]

From: Namhyung Kim <namhyung.kim@xxxxxxx>

It's helpful for debugging on tracing features.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jeremy Eder <jeder@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>,
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-rjysr9ljiesymgk4qblteaty@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/header.c           |  4 ++-
 tools/perf/util/trace-event-read.c | 53 ++++++++++++++++++++++++++------------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 00fd8a8850d3..c567d9f0aa92 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2803,8 +2803,10 @@ static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
 	}
 
 	event = pevent_find_event(pevent, evsel->attr.config);
-	if (event == NULL)
+	if (event == NULL) {
+		pr_debug("cannot find event format for %d\n", (int)evsel->attr.config);
 		return -1;
+	}
 
 	if (!evsel->name) {
 		snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);
diff --git a/tools/perf/util/trace-event-read.c b/tools/perf/util/trace-event-read.c
index 61c7162c31c7..27420159bf69 100644
--- a/tools/perf/util/trace-event-read.c
+++ b/tools/perf/util/trace-event-read.c
@@ -260,39 +260,53 @@ static int read_header_files(struct pevent *pevent)
 
 static int read_ftrace_file(struct pevent *pevent, unsigned long long size)
 {
+	int ret;
 	char *buf;
 
 	buf = malloc(size);
-	if (buf == NULL)
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
 		return -1;
+	}
 
-	if (do_read(buf, size) < 0) {
-		free(buf);
-		return -1;
+	ret = do_read(buf, size);
+	if (ret < 0) {
+		pr_debug("error reading ftrace file.\n");
+		goto out;
 	}
 
-	parse_ftrace_file(pevent, buf, size);
+	ret = parse_ftrace_file(pevent, buf, size);
+	if (ret < 0)
+		pr_debug("error parsing ftrace file.\n");
+out:
 	free(buf);
-	return 0;
+	return ret;
 }
 
 static int read_event_file(struct pevent *pevent, char *sys,
 			    unsigned long long size)
 {
+	int ret;
 	char *buf;
 
 	buf = malloc(size);
-	if (buf == NULL)
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
 		return -1;
+	}
 
-	if (do_read(buf, size) < 0) {
+	ret = do_read(buf, size);
+	if (ret < 0) {
 		free(buf);
-		return -1;
+		goto out;
 	}
 
-	parse_event_file(pevent, buf, size, sys);
+	ret = parse_event_file(pevent, buf, size, sys);
+	if (ret < 0)
+		pr_debug("error parsing event file.\n");
+out:
 	free(buf);
-	return 0;
+	return ret;
 }
 
 static int read_ftrace_files(struct pevent *pevent)
@@ -345,6 +359,7 @@ static int read_saved_cmdline(struct pevent *pevent)
 {
 	unsigned long long size;
 	char *buf;
+	int ret;
 
 	/* it can have 0 size */
 	size = read8(pevent);
@@ -352,18 +367,22 @@ static int read_saved_cmdline(struct pevent *pevent)
 		return 0;
 
 	buf = malloc(size + 1);
-	if (buf == NULL)
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
 		return -1;
+	}
 
-	if (do_read(buf, size) < 0) {
-		free(buf);
-		return -1;
+	ret = do_read(buf, size);
+	if (ret < 0) {
+		pr_debug("error reading saved cmdlines\n");
+		goto out;
 	}
 
 	parse_saved_cmdline(pevent, buf, size);
-
+	ret = 0;
+out:
 	free(buf);
-	return 0;
+	return ret;
 }
 
 ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
-- 
2.9.3