perf tools: Fix snprint warnings for gcc 8

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

  tests/mem.c: In function ‘check’:
  tests/mem.c:19:48: error: ‘%s’ 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@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Link: http://lkml.kernel.org/r/20180319082902.4518-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 4 insertions, 4 deletions

diff --git a/tools/perf/tests/attr.c b/tools/perf/tests/attr.c
index 97f64ad..05dfe11 100644
--- a/tools/perf/tests/attr.c
+++ b/tools/perf/tests/attr.c
@@ -170,8 +170,8 @@ static int run_dir(const char *d, const char *perf)
 	if (verbose > 0)
 		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) ? TEST_FAIL : TEST_OK;
 }
diff --git a/tools/perf/tests/mem.c b/tools/perf/tests/mem.c
index 21952e1..0f82ee9 100644
--- a/tools/perf/tests/mem.c
+++ b/tools/perf/tests/mem.c
@@ -16,7 +16,7 @@ static int check(union perf_mem_data_src data_src,
 
 	n = perf_mem__snp_scnprintf(out, sizeof out, &mi);
 	n += perf_mem__lvl_scnprintf(out + n, sizeof out - n, &mi);
-	snprintf(failure, sizeof failure, "unexpected %s", out);
+	scnprintf(failure, sizeof failure, "unexpected %s", out);
 	TEST_ASSERT_VAL(failure, !strcmp(string, out));
 	return 0;
 }
diff --git a/tools/perf/tests/pmu.c b/tools/perf/tests/pmu.c
index 9abca26..7bedf86 100644
--- a/tools/perf/tests/pmu.c
+++ b/tools/perf/tests/pmu.c
@@ -98,7 +98,7 @@ 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)