static int run(int argc, char *argv[]) {
_cleanup_close_ int fd = -1, saved_stderr = -1;
int r;
log_parse_environment();
log_open();
r = parse_argv(argc, argv);
if (r <= 0)
return r;
fd = sd_journal_stream_fd(arg_identifier, arg_priority, arg_level_prefix);
if (fd < 0)
return log_error_errno(fd, "Failed to create stream fd: %m");
saved_stderr = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, 3);
r = rearrange_stdio(STDIN_FILENO, fd, fd); /* Invalidates fd on succcess + error! */
TAKE_FD(fd);
if (r < 0)
return log_error_errno(r, "Failed to rearrange stdout/stderr: %m");
if (argc <= optind)
(void) execl("/bin/cat", "/bin/cat", NULL);
else
(void) execvp(argv[optind], argv + optind);
r = -errno;
/* Let's try to restore a working stderr, so we can print the error message */
if (saved_stderr >= 0)
(void) dup3(saved_stderr, STDERR_FILENO, 0);
return log_error_errno(r, "Failed to execute process: %m");
}
static int do_spawn(const char *path, char *argv[], int stdout_fd, pid_t *pid) {
pid_t _pid;
int r;
if (null_or_empty_path(path)) {
log_debug("%s is empty (a mask).", path);
return 0;
}
r = safe_fork("(direxec)", FORK_DEATHSIG|FORK_LOG, &_pid);
if (r < 0)
return r;
if (r == 0) {
char *_argv[2];
if (stdout_fd >= 0) {
r = rearrange_stdio(STDIN_FILENO, stdout_fd, STDERR_FILENO);
if (r < 0)
_exit(EXIT_FAILURE);
}
(void) rlimit_nofile_safe();
if (!argv) {
_argv[0] = (char*) path;
_argv[1] = NULL;
argv = _argv;
} else
argv[0] = (char*) path;
execv(path, argv);
log_error_errno(errno, "Failed to execute %s: %m", path);
_exit(EXIT_FAILURE);
}
*pid = _pid;
return 1;
}
static void test_rearrange_stdio(void) {
pid_t pid;
int r;
r = safe_fork("rearrange", FORK_WAIT|FORK_LOG, &pid);
assert_se(r >= 0);
if (r == 0) {
_cleanup_free_ char *path = NULL;
char buffer[10];
/* Child */
safe_close(STDERR_FILENO); /* Let's close an fd < 2, to make it more interesting */
assert_se(rearrange_stdio(-1, -1, -1) >= 0);
assert_se(fd_get_path(STDIN_FILENO, &path) >= 0);
assert_se(path_equal(path, "/dev/null"));
path = mfree(path);
assert_se(fd_get_path(STDOUT_FILENO, &path) >= 0);
assert_se(path_equal(path, "/dev/null"));
path = mfree(path);
assert_se(fd_get_path(STDOUT_FILENO, &path) >= 0);
assert_se(path_equal(path, "/dev/null"));
path = mfree(path);
safe_close(STDIN_FILENO);
safe_close(STDOUT_FILENO);
safe_close(STDERR_FILENO);
{
int pair[2];
assert_se(pipe(pair) >= 0);
assert_se(pair[0] == 0);
assert_se(pair[1] == 1);
assert_se(fd_move_above_stdio(0) == 3);
}
assert_se(open("/dev/full", O_WRONLY|O_CLOEXEC) == 0);
assert_se(acquire_data_fd("foobar", 6, 0) == 2);
assert_se(rearrange_stdio(2, 0, 1) >= 0);
assert_se(write(1, "x", 1) < 0 && errno == ENOSPC);
assert_se(write(2, "z", 1) == 1);
assert_se(read(3, buffer, sizeof(buffer)) == 1);
assert_se(buffer[0] == 'z');
assert_se(read(0, buffer, sizeof(buffer)) == 6);
assert_se(memcmp(buffer, "foobar", 6) == 0);
assert_se(rearrange_stdio(-1, 1, 2) >= 0);
assert_se(write(1, "a", 1) < 0 && errno == ENOSPC);
assert_se(write(2, "y", 1) == 1);
assert_se(read(3, buffer, sizeof(buffer)) == 1);
assert_se(buffer[0] == 'y');
assert_se(fd_get_path(0, &path) >= 0);
assert_se(path_equal(path, "/dev/null"));
path = mfree(path);
_exit(EXIT_SUCCESS);
}
}
