Commit 929e54a9 authored by Jianlin Lv's avatar Jianlin Lv Committed by Alexei Starovoitov
Browse files

bpf: Fix compilation warning of selftests 



Clang compiler version: 12.0.0
The following warning appears during the selftests/bpf compilation:

prog_tests/send_signal.c:51:3: warning: ignoring return value of ‘write’,
declared with attribute warn_unused_result [-Wunused-result]
   51 |   write(pipe_c2p[1], buf, 1);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~
prog_tests/send_signal.c:54:3: warning: ignoring return value of ‘read’,
declared with attribute warn_unused_result [-Wunused-result]
   54 |   read(pipe_p2c[0], buf, 1);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
......

prog_tests/stacktrace_build_id_nmi.c:13:2: warning: ignoring return value
of ‘fscanf’,declared with attribute warn_unused_result [-Wunused-resul]
   13 |  fscanf(f, "%llu", &sample_freq);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

test_tcpnotify_user.c:133:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  133 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~
test_tcpnotify_user.c:138:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  138 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~
test_tcpnotify_user.c:143:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  143 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~

Add code that fix compilation warning about ignoring return value and
handles any errors; Check return value of library`s API make the code
more secure.

Signed-off-by: default avatarJianlin Lv <Jianlin.Lv@arm.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806104224.95306-1-Jianlin.Lv@arm.com
parent 6fc5916c

tools/testing/selftests/bpf/prog_tests/send_signal.c

+8 −10
Original line number Diff line number Diff line
@@ -48,21 +48,19 @@ static void test_send_signal_common(struct perf_event_attr *attr, 
		close(pipe_p2c[1]); /* close write */



		/* notify parent signal handler is installed */

		write(pipe_c2p[1], buf, 1);

		CHECK(write(pipe_c2p[1], buf, 1) != 1, "pipe_write", "err %d\n", -errno);



		/* make sure parent enabled bpf program to send_signal */

		read(pipe_p2c[0], buf, 1);

		CHECK(read(pipe_p2c[0], buf, 1) != 1, "pipe_read", "err %d\n", -errno);



		/* wait a little for signal handler */

		sleep(1);



		if (sigusr1_received)

			write(pipe_c2p[1], "2", 1);

		else

			write(pipe_c2p[1], "0", 1);

		buf[0] = sigusr1_received ? '2' : '0';

		CHECK(write(pipe_c2p[1], buf, 1) != 1, "pipe_write", "err %d\n", -errno);



		/* wait for parent notification and exit */

		read(pipe_p2c[0], buf, 1);

		CHECK(read(pipe_p2c[0], buf, 1) != 1, "pipe_read", "err %d\n", -errno);



		close(pipe_c2p[1]);

		close(pipe_p2c[0]);
@@ -99,7 +97,7 @@ static void test_send_signal_common(struct perf_event_attr *attr, 
	}



	/* wait until child signal handler installed */

	read(pipe_c2p[0], buf, 1);

	CHECK(read(pipe_c2p[0], buf, 1) != 1, "pipe_read", "err %d\n", -errno);



	/* trigger the bpf send_signal */

	skel->bss->pid = pid;
@@ -107,7 +105,7 @@ static void test_send_signal_common(struct perf_event_attr *attr, 
	skel->bss->signal_thread = signal_thread;



	/* notify child that bpf program can send_signal now */

	write(pipe_p2c[1], buf, 1);

	CHECK(write(pipe_p2c[1], buf, 1) != 1, "pipe_write", "err %d\n", -errno);



	/* wait for result */

	err = read(pipe_c2p[0], buf, 1);
@@ -121,7 +119,7 @@ static void test_send_signal_common(struct perf_event_attr *attr, 
	CHECK(buf[0] != '2', test_name, "incorrect result\n");



	/* notify child safe to exit */

	write(pipe_p2c[1], buf, 1);

	CHECK(write(pipe_p2c[1], buf, 1) != 1, "pipe_write", "err %d\n", -errno);



disable_pmu:

	close(pmu_fd);

tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c

+3 −1
Original line number Diff line number Diff line
@@ -6,11 +6,13 @@ static __u64 read_perf_max_sample_freq(void) 
{

	__u64 sample_freq = 5000; /* fallback to 5000 on error */

	FILE *f;

	__u32 duration = 0;



	f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");

	if (f == NULL)

		return sample_freq;

	fscanf(f, "%llu", &sample_freq);

	CHECK(fscanf(f, "%llu", &sample_freq) != 1, "Get max sample rate",

		  "return default value: 5000,err %d\n", -errno);

	fclose(f);

	return sample_freq;

}

tools/testing/selftests/bpf/test_tcpnotify_user.c

+10 −3
Original line number Diff line number Diff line
@@ -124,17 +124,24 @@ int main(int argc, char **argv) 
	sprintf(test_script,

		"iptables -A INPUT -p tcp --dport %d -j DROP",

		TESTPORT);

	system(test_script);

	if (system(test_script)) {

		printf("FAILED: execute command: %s, err %d\n", test_script, -errno);

		goto err;

	}



	sprintf(test_script,

		"nc 127.0.0.1 %d < /etc/passwd > /dev/null 2>&1 ",

		TESTPORT);

	system(test_script);

	if (system(test_script))

		printf("execute command: %s, err %d\n", test_script, -errno);



	sprintf(test_script,

		"iptables -D INPUT -p tcp --dport %d -j DROP",

		TESTPORT);

	system(test_script);

	if (system(test_script)) {

		printf("FAILED: execute command: %s, err %d\n", test_script, -errno);

		goto err;

	}



	rv = bpf_map_lookup_elem(bpf_map__fd(global_map), &key, &g);

	if (rv != 0) {