selftests/powerpc: Use snprintf to construct DSCR sysfs interface paths

Currently sprintf is used, and while paths should never exceed
the size of the buffer it is theoretically possible since
dirent.d_name is 256 bytes. As a result this trips
-Wformat-overflow, and since the test is built with -Wall -Werror
the causes the build to fail. Switch to using snprintf and skip
any paths which are too long for the filename buffer.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c b/tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c
index 17fb1b43c320dbe8f5f943792303bdb93bee4f1f..1899bd85121f0ba46cec282f8dcfadc4cc34fa2c 100644 (file)
--- a/tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c
+++ b/tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c
@@ -53,6 +53,8 @@ static int check_all_cpu_dscr_defaults(unsigned long val)
        }
 
        while ((dp = readdir(sysfs))) {
+               int len;
+
                if (!(dp->d_type & DT_DIR))
                        continue;
                if (!strcmp(dp->d_name, "cpuidle"))
@@ -60,7 +62,9 @@ static int check_all_cpu_dscr_defaults(unsigned long val)
                if (!strstr(dp->d_name, "cpu"))
                        continue;
 
-               sprintf(file, "%s%s/dscr", CPU_PATH, dp->d_name);
+               len = snprintf(file, LEN_MAX, "%s%s/dscr", CPU_PATH, dp->d_name);
+               if (len >= LEN_MAX)
+                       continue;
                if (access(file, F_OK))
                        continue;