This splits up the get_proc_stat function to make it so we can use it as a generic helper to read the nth field from multiple different files, versus replicating the logic in multiple places.

Signed-off-by: Sargun Dhillon sargun@sargun.me Cc: linux-kselftest@vger.kernel.org --- tools/testing/selftests/seccomp/seccomp_bpf.c | 54 +++++++++++++------ 1 file changed, 38 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index ab340c4759a3..4fb5eda89223 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -4231,32 +4231,54 @@ TEST(user_notification_addfd_rlimit) close(memfd); }

-static char get_proc_stat(int pid) +/* + * gen_nth - Get the nth, space separated entry in a file. + * + * Returns the length of the read field. + * Throws error if field is zero-lengthed. + */ +static ssize_t get_nth(struct __test_metadata *_metadata, const char *path, + const unsigned int position, char **entry) { - char proc_path[100] = {0}; char *line = NULL; - size_t len = 0; + unsigned int i; ssize_t nread; - char status; + size_t len = 0; FILE *f; - int i;

- snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid); - f = fopen(proc_path, "r"); - if (f == NULL) - ksft_exit_fail_msg("%s - Could not open %s\n", - strerror(errno), proc_path); + f = fopen(path, "r"); + ASSERT_NE(f, NULL) { + TH_LOG("Coud not open %s: %s", path, strerror(errno)); + }

- for (i = 0; i < 3; i++) { + for (i = 0; i < position; i++) { nread = getdelim(&line, &len, ' ', f); - if (nread <= 0) - ksft_exit_fail_msg("Failed to read status: %s\n", - strerror(errno)); + ASSERT_GE(nread, 0) { + TH_LOG("Failed to read %d entry in file %s", i, path); + } } + fclose(f); + + ASSERT_GT(nread, 0) { + TH_LOG("Entry in file %s had zero length", path); + } + + *entry = line; + return nread - 1; +} + +/* For a given PID, get the task state (D, R, etc...) */ +static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid) +{ + char proc_path[100] = {0}; + char status; + char *line; + + snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid); + ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1);

status = *line; free(line); - fclose(f);

return status; } @@ -4317,7 +4339,7 @@ TEST(user_notification_fifo) /* This spins until all of the children are sleeping */ restart_wait: for (i = 0; i < ARRAY_SIZE(pids); i++) { - if (get_proc_stat(pids[i]) != 'S') { + if (get_proc_stat(_metadata, pids[i]) != 'S') { nanosleep(&delay, NULL); goto restart_wait; }