From 929e54a989680c6f134b02293732030b897475dc Mon Sep 17 00:00:00 2001 From: Jianlin Lv Date: Thu, 6 Aug 2020 18:42:24 +0800 Subject: [PATCH] bpf: Fix compilation warning of selftests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Jianlin Lv Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200806104224.95306-1-Jianlin.Lv@arm.com --- .../selftests/bpf/prog_tests/send_signal.c | 18 ++++++++---------- .../bpf/prog_tests/stacktrace_build_id_nmi.c | 4 +++- .../selftests/bpf/test_tcpnotify_user.c | 13 ++++++++++--- 3 files changed, 21 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index 504abb7bfb95..7043e6ded0e6 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -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); diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c index f002e3090d92..11a769e18f5d 100644 --- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c +++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c @@ -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; } diff --git a/tools/testing/selftests/bpf/test_tcpnotify_user.c b/tools/testing/selftests/bpf/test_tcpnotify_user.c index 8549b31716ab..73da7fe8c152 100644 --- a/tools/testing/selftests/bpf/test_tcpnotify_user.c +++ b/tools/testing/selftests/bpf/test_tcpnotify_user.c @@ -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) {