idlestat: Check return value in cpuidle_get_target_residency

The return value from call to fscanf was previously ignored.
Now the function cpuidle_get_target_residency will return -1
if fscanf fails to parse the value.

Signed-off-by: Tuukka Tikkanen <tuukka.tikkanen@linaro.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/idlestat.c b/idlestat.c
index 4392920..dbf8400 100644
--- a/idlestat.c
+++ b/idlestat.c
@@ -271,6 +271,7 @@ int cpuidle_get_target_residency(int cpu, int state)
 	char *fpath;
 	unsigned int tr;
 	FILE *snf;
+	int ret;
 
 	if (asprintf(&fpath, CPUIDLE_STATE_TARGETRESIDENCY_PATH_FORMAT,
 				cpu, state) < 0)
@@ -283,10 +284,10 @@ int cpuidle_get_target_residency(int cpu, int state)
 		free(fpath);
 		return -1;
 	}
-	fscanf(snf, "%u", &tr);
+	ret = fscanf(snf, "%u", &tr);
 	fclose(snf);
 
-	return tr;
+	return (ret == 1) ? tr : -1;
 }
 
 /**