[PATCH 3.16 360/366] perf tools: Fix snprint warnings for gcc 8

[Ben Hutchings]

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <jolsa@xxxxxxxxxx>

commit 77f18153c080855e1c3fb520ca31a4e61530121d upstream.

With gcc 8 we get new set of snprintf() warnings that breaks the
compilation, one example:

  tests/mem.c: In function âcheckâ:
  tests/mem.c:19:48: error: â%sâ directive output may be truncated writing \
        up to 99 bytes into a region of size 89 [-Werror=format-truncation=]
    snprintf(failure, sizeof failure, "unexpected %s", out);

The gcc docs says:

 To avoid the warning either use a bigger buffer or handle the
 function's return value which indicates whether or not its output
 has been truncated.

Given that all these warnings are harmless, because the code either
properly fails due to uncomplete file path or we don't care for
truncated output at all, I'm changing all those snprintf() calls to
scnprintf(), which actually 'checks' for the snprint return value so the
gcc stays silent.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20180319082902.4518-1-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
[bwh: Backported to 3.16: Drop changes in tools/perf/tests/mem.c]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 tools/perf/builtin-script.c    | 22 +++++++++++-----------
 tools/perf/tests/attr.c        |  4 ++--
 tools/perf/tests/mem.c         |  2 +-
 tools/perf/tests/pmu.c         |  2 +-
 tools/perf/util/cgroup.c       |  2 +-
 tools/perf/util/parse-events.c |  4 ++--
 tools/perf/util/pmu.c          |  2 +-
 7 files changed, 19 insertions(+), 19 deletions(-)

--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1235,8 +1235,8 @@ static int list_available_scripts(const
 		return -1;
 
 	for_each_lang(scripts_path, scripts_dir, lang_dirent) {
-		snprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
-			 lang_dirent->d_name);
+		scnprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
+			  lang_dirent->d_name);
 		lang_dir = opendir(lang_path);
 		if (!lang_dir)
 			continue;
@@ -1245,8 +1245,8 @@ static int list_available_scripts(const
 			script_root = get_script_root(script_dirent, REPORT_SUFFIX);
 			if (script_root) {
 				desc = script_desc__findnew(script_root);
-				snprintf(script_path, MAXPATHLEN, "%s/%s",
-					 lang_path, script_dirent->d_name);
+				scnprintf(script_path, MAXPATHLEN, "%s/%s",
+					  lang_path, script_dirent->d_name);
 				read_script_info(desc, script_path);
 				free(script_root);
 			}
@@ -1282,7 +1282,7 @@ static int check_ev_match(char *dir_name
 	int match, len;
 	FILE *fp;
 
-	sprintf(filename, "%s/bin/%s-record", dir_name, scriptname);
+	scnprintf(filename, MAXPATHLEN, "%s/bin/%s-record", dir_name, scriptname);
 
 	fp = fopen(filename, "r");
 	if (!fp)
@@ -1358,8 +1358,8 @@ int find_scripts(char **scripts_array, c
 	}
 
 	for_each_lang(scripts_path, scripts_dir, lang_dirent) {
-		snprintf(lang_path, MAXPATHLEN, "%s/%s", scripts_path,
-			 lang_dirent->d_name);
+		scnprintf(lang_path, MAXPATHLEN, "%s/%s", scripts_path,
+			  lang_dirent->d_name);
 #ifdef NO_LIBPERL
 		if (strstr(lang_path, "perl"))
 			continue;
@@ -1414,8 +1414,8 @@ static char *get_script_path(const char
 		return NULL;
 
 	for_each_lang(scripts_path, scripts_dir, lang_dirent) {
-		snprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
-			 lang_dirent->d_name);
+		scnprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
+			  lang_dirent->d_name);
 		lang_dir = opendir(lang_path);
 		if (!lang_dir)
 			continue;
@@ -1426,8 +1426,8 @@ static char *get_script_path(const char
 				free(__script_root);
 				closedir(lang_dir);
 				closedir(scripts_dir);
-				snprintf(script_path, MAXPATHLEN, "%s/%s",
-					 lang_path, script_dirent->d_name);
+				scnprintf(script_path, MAXPATHLEN, "%s/%s",
+					  lang_path, script_dirent->d_name);
 				return strdup(script_path);
 			}
 			free(__script_root);
--- a/tools/perf/tests/attr.c
+++ b/tools/perf/tests/attr.c
@@ -147,8 +147,8 @@ static int run_dir(const char *d, const
 	if (verbose)
 		vcnt++;
 
-	snprintf(cmd, 3*PATH_MAX, PYTHON " %s/attr.py -d %s/attr/ -p %s %.*s",
-		 d, d, perf, vcnt, v);
+	scnprintf(cmd, 3*PATH_MAX, PYTHON " %s/attr.py -d %s/attr/ -p %s %.*s",
+		  d, d, perf, vcnt, v);
 
 	return system(cmd);
 }
--- a/tools/perf/tests/pmu.c
+++ b/tools/perf/tests/pmu.c
@@ -95,7 +95,7 @@ static char *test_format_dir_get(void)
 		struct test_format *format = &test_formats[i];
 		FILE *file;
 
-		snprintf(name, PATH_MAX, "%s/%s", dir, format->name);
+		scnprintf(name, PATH_MAX, "%s/%s", dir, format->name);
 
 		file = fopen(name, "w");
 		if (!file)
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -64,7 +64,7 @@ static int open_cgroup(char *name)
 	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
 		return -1;
 
-	snprintf(path, PATH_MAX, "%s/%s", mnt, name);
+	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
 
 	fd = open(path, O_RDONLY);
 	if (fd == -1)
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -182,8 +182,8 @@ struct tracepoint_path *tracepoint_id_to
 
 		for_each_event(sys_dirent, evt_dir, evt_dirent) {
 
-			snprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
-				 evt_dirent->d_name);
+			scnprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
+				  evt_dirent->d_name);
 			fd = open(evt_path, O_RDONLY);
 			if (fd < 0)
 				continue;
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -240,7 +240,7 @@ static int pmu_aliases_parse(char *dir,
 		if (len > 6 && !strcmp(name + len - 6, ".scale"))
 			continue;
 
-		snprintf(path, PATH_MAX, "%s/%s", dir, name);
+		scnprintf(path, PATH_MAX, "%s/%s", dir, name);
 
 		file = fopen(path, "r");
 		if (!file) {