static void sync_with_progress(void) {
unsigned long long dirty = ULONG_LONG_MAX;
unsigned checks;
pid_t pid;
int r;
BLOCK_SIGNALS(SIGCHLD);
/* Due to the possiblity of the sync operation hanging, we fork a child process and monitor the progress. If
* the timeout lapses, the assumption is that that particular sync stalled. */
r = asynchronous_sync(&pid);
if (r < 0) {
log_error_errno(r, "Failed to fork sync(): %m");
return;
}
log_info("Syncing filesystems and block devices.");
/* Start monitoring the sync operation. If more than
* SYNC_PROGRESS_ATTEMPTS lapse without progress being made,
* we assume that the sync is stalled */
for (checks = 0; checks < SYNC_PROGRESS_ATTEMPTS; checks++) {
r = wait_for_terminate_with_timeout(pid, SYNC_TIMEOUT_USEC);
if (r == 0)
/* Sync finished without error.
* (The sync itself does not return an error code) */
return;
else if (r == -ETIMEDOUT) {
/* Reset the check counter if the "Dirty" value is
* decreasing */
if (sync_making_progress(&dirty))
checks = 0;
} else {
log_error_errno(r, "Failed to sync filesystems and block devices: %m");
return;
}
}
/* Only reached in the event of a timeout. We should issue a kill
* to the stray process. */
log_error("Syncing filesystems and block devices - timed out, issuing SIGKILL to PID "PID_FMT".", pid);
(void) kill(pid, SIGKILL);
}
int main(int argc, char *argv[]) {
int fd;
char name[] = "/tmp/test-asynchronous_close.XXXXXX";
fd = mkostemp_safe(name);
assert_se(fd >= 0);
asynchronous_close(fd);
assert_se(asynchronous_job(async_func, NULL) >= 0);
assert_se(asynchronous_sync(NULL) >= 0);
sleep(1);
assert_se(fcntl(fd, F_GETFD) == -1);
assert_se(test_async);
unlink(name);
return 0;
}