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shutdown: propagate mount() failures from child to parent

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Let's propagate the actual error code up, as we usual do.

Inspired by: #25168
This commit is contained in:
Lennart Poettering
2023-01-09 22:17:04 +01:00
parent e29684a1ba
commit b293bb2316
3 changed files with 59 additions and 12 deletions
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src/basic/process-util.c
+17
View File
@@ -765,6 +765,23 @@ void sigterm_wait(pid_t pid) {
(void) wait_for_terminate(pid, NULL);
}
void sigkill_nowait(pid_t pid) {
assert(pid > 1);
(void) kill(pid, SIGKILL);
}
void sigkill_nowaitp(pid_t *pid) {
PROTECT_ERRNO;
if (!pid)
return;
if (*pid <= 1)
return;
sigkill_nowait(*pid);
}
int kill_and_sigcont(pid_t pid, int sig) {
int r;
src/basic/process-util.h
+2
View File
@@ -68,6 +68,8 @@ int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout);
void sigkill_wait(pid_t pid);
void sigkill_waitp(pid_t *pid);
void sigterm_wait(pid_t pid);
void sigkill_nowait(pid_t pid);
void sigkill_nowaitp(pid_t *pid);
int kill_and_sigcont(pid_t pid, int sig);
src/shutdown/umount.c
+40 -12
View File
@@ -594,19 +594,26 @@ static void log_umount_blockers(const char *mnt) {
}
static int remount_with_timeout(MountPoint *m, bool last_try) {
pid_t pid;
_cleanup_(close_pairp) int pfd[2] = PIPE_EBADF;
_cleanup_(sigkill_nowaitp) pid_t pid = 0;
int r;
BLOCK_SIGNALS(SIGCHLD);
assert(m);
r = pipe2(pfd, O_CLOEXEC|O_NONBLOCK);
if (r < 0)
return r;
/* Due to the possibility of a remount operation hanging, we fork a child process and set a
* timeout. If the timeout lapses, the assumption is that the particular remount failed. */
r = safe_fork("(sd-remount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
pfd[0] = safe_close(pfd[0]);
log_info("Remounting '%s' read-only with options '%s'.", m->path, strempty(m->remount_options));
/* Start the mount operation here in the child */
@@ -617,35 +624,49 @@ static int remount_with_timeout(MountPoint *m, bool last_try) {
"Failed to remount '%s' read-only: %m",
m->path);
(void) write(pfd[1], &r, sizeof(r)); /* try to send errno up */
_exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
}
pfd[1] = safe_close(pfd[1]);
r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC);
if (r == -ETIMEDOUT) {
if (r == -ETIMEDOUT)
log_error_errno(r, "Remounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid);
(void) kill(pid, SIGKILL);
} else if (r == -EPROTO)
log_debug_errno(r, "Remounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
else if (r < 0)
else if (r == -EPROTO) {
/* Try to read error code from child */
if (read(pfd[0], &r, sizeof(r)) == sizeof(r))
log_debug_errno(r, "Remounting '%s' failed abnormally, child process " PID_FMT " failed: %m", m->path, pid);
else
log_debug_errno(r, "Remounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
TAKE_PID(pid); /* child exited (just not as we expected) hence don't kill anymore */
} else if (r < 0)
log_error_errno(r, "Remounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid);
return r;
}
static int umount_with_timeout(MountPoint *m, bool last_try) {
pid_t pid;
_cleanup_(close_pairp) int pfd[2] = PIPE_EBADF;
_cleanup_(sigkill_nowaitp) pid_t pid = 0;
int r;
BLOCK_SIGNALS(SIGCHLD);
assert(m);
r = pipe2(pfd, O_CLOEXEC|O_NONBLOCK);
if (r < 0)
return r;
/* Due to the possibility of a umount operation hanging, we fork a child process and set a
* timeout. If the timeout lapses, the assumption is that the particular umount failed. */
r = safe_fork("(sd-umount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
pfd[0] = safe_close(pfd[0]);
log_info("Unmounting '%s'.", m->path);
/* Start the mount operation here in the child Using MNT_FORCE causes some filesystems
@@ -663,16 +684,23 @@ static int umount_with_timeout(MountPoint *m, bool last_try) {
log_umount_blockers(m->path);
}
(void) write(pfd[1], &r, sizeof(r)); /* try to send errno up */
_exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
}
pfd[1] = safe_close(pfd[1]);
r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC);
if (r == -ETIMEDOUT) {
if (r == -ETIMEDOUT)
log_error_errno(r, "Unmounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid);
(void) kill(pid, SIGKILL);
} else if (r == -EPROTO)
log_debug_errno(r, "Unmounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
else if (r < 0)
else if (r == -EPROTO) {
/* Try to read error code from child */
if (read(pfd[0], &r, sizeof(r)) == sizeof(r))
log_debug_errno(r, "Unmounting '%s' failed abnormally, child process " PID_FMT " failed: %m", m->path, pid);
else
r = log_debug_errno(EPROTO, "Unmounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid);
TAKE_PID(pid); /* It died, but abnormally, no purpose in killing */
} else if (r < 0)
log_error_errno(r, "Unmounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid);
return r;