[PATCH] selftests/capabilities: fix warn_unused_result build warnings

[Amer Al Shanawany]

Fix the following warnings by adding return check and error handling.

test_execve.c: In function ‘do_tests’:
test_execve.c:100:17: warning: ignoring return value of
 ‘capng_get_caps_process’
 declared with attribute ‘warn_unused_result’ [-Wunused-result]
  100 |                 capng_get_caps_process();
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
validate_cap.c: In function ‘main’:
validate_cap.c:47:9: warning: ignoring return value of
 ‘capng_get_caps_process’
declared with attribute ‘warn_unused_result’ [-Wunused-result]
   47 |         capng_get_caps_process();
      |         ^~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Amer Al Shanawany <amer.shanaw...@gmail.com>
---
 tools/testing/selftests/capabilities/test_execve.c  | 12 +++++++++---
 tools/testing/selftests/capabilities/validate_cap.c |  7 ++++++-
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/capabilities/test_execve.c 
b/tools/testing/selftests/capabilities/test_execve.c
index 7cde07a5df78..47bad7ddc5bc 100644
--- a/tools/testing/selftests/capabilities/test_execve.c
+++ b/tools/testing/selftests/capabilities/test_execve.c
@@ -82,7 +82,7 @@ static bool create_and_enter_ns(uid_t inner_uid)
 {
        uid_t outer_uid;
        gid_t outer_gid;
-       int i;
+       int i, ret;
        bool have_outer_privilege;
 
        outer_uid = getuid();
@@ -97,7 +97,10 @@ static bool create_and_enter_ns(uid_t inner_uid)
                        ksft_exit_fail_msg("setresuid - %s\n", strerror(errno));
 
                // Re-enable effective caps
-               capng_get_caps_process();
+               ret = capng_get_caps_process();
+               if (ret == -1)
+                       ksft_exit_fail_msg("capng_get_caps_process failed\n");
+
                for (i = 0; i < CAP_LAST_CAP; i++)
                        if (capng_have_capability(CAPNG_PERMITTED, i))
                                capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
@@ -207,6 +210,7 @@ static void exec_validate_cap(bool eff, bool perm, bool 
inh, bool ambient)
 
 static int do_tests(int uid, const char *our_path)
 {
+       int ret;
        bool have_outer_privilege = create_and_enter_ns(uid);
 
        int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
@@ -250,7 +254,9 @@ static int do_tests(int uid, const char *our_path)
                        ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
        }
 
-       capng_get_caps_process();
+       ret = capng_get_caps_process();
+       if (ret == -1)
+               ksft_exit_fail_msg("capng_get_caps_process failed\n");
 
        /* Make sure that i starts out clear */
        capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
diff --git a/tools/testing/selftests/capabilities/validate_cap.c 
b/tools/testing/selftests/capabilities/validate_cap.c
index 60b4e7b716a7..65f2a1c89239 100644
--- a/tools/testing/selftests/capabilities/validate_cap.c
+++ b/tools/testing/selftests/capabilities/validate_cap.c
@@ -28,6 +28,7 @@ static bool bool_arg(char **argv, int i)
 int main(int argc, char **argv)
 {
        const char *atsec = "";
+       int ret;
 
        /*
         * Be careful just in case a setgid or setcapped copy of this
@@ -44,7 +45,11 @@ int main(int argc, char **argv)
                atsec = " (AT_SECURE is not set)";
 #endif
 
-       capng_get_caps_process();
+       ret = capng_get_caps_process();
+       if (ret == -1) {
+               ksft_print_msg("capng_get_caps_process failed\n");
+               return 1;
+       }
 
        if (capng_have_capability(CAPNG_EFFECTIVE, CAP_NET_BIND_SERVICE) != 
bool_arg(argv, 1)) {
                ksft_print_msg("Wrong effective state%s\n", atsec);
-- 
2.43.0