wt/finit
1
0
Fork 0
mirror of https://github.com/troglobit/finit.git synced 2026-10-10 16:52:39 +07:00
Code Issues Packages Projects Releases Wiki Activity

The science of unmounting file systems on Debian

Browse Source 
That's maybe a bit unfair.  This patch implements a brief version of
what is really needed to safely unmount all file systems on a modern
Linux distribution.  Yes, it's this insane.  (Who am I kidding, it's
worse!  Just have a look at the ancient scrolls hidden in your /etc!)

Here is where we use the new plugin_exit() and api_exit() API's from an
earlier patch.  Making sure to exit and close any kernel descriptors.
Then follows a bizarre spell cast on leaking descriptors, rebooting in
a child, remounting / as read-only, and a whole slew of other R rated
stuff to prevent mount/umount from returning 32 ...

Stay safe people, use protection always!

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
This commit is contained in:
Joachim Nilsson
2016-07-28 23:48:39 +02:00
parent 57514130fc
commit 968f1bf991
1 changed files with 36 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
sig.c
+36 -6
View File
@@ -88,18 +88,48 @@ void do_shutdown(int sig)
_d("Sending SIGKILL to remaining processes.");
kill(-1, SIGKILL);
sync();
sync();
_d("Unmounting file systems, remounting / read-only.");
run("/bin/umount -fa 2>/dev/null");
run("/bin/mount -n -o remount,ro / 2>/dev/null");
run("/sbin/swapoff -ea");
debug = 1;
plugin_exit();
api_exit();
/* Reap 'em */
while (waitpid(-1, NULL, WNOHANG) > 0)
;
/* Close all local non-console descriptors */
for (int fd = 3; fd < 128; fd++)
close(fd);
if (vfork()) {
/*
* Put PID 1 aside and let child perform reboot/halt
* kernel may exit child and we don't want to exit PID 1
* ... causing "aiii killing init" during reboot ...
*/
return;
}
/* Unmount any tmpfs before unmounting swap ... */
run("/bin/umount -r -a");
run("/sbin/swapoff -e -a");
/* Now, unmount everything else ... err, just force it. */
run("/bin/umount -n -f -r -a");
/* We sit on / so we must remount it ro, try all the things! */
run("/bin/mount -n -o remount,ro -t dummytype dummydev /");
run("/bin/mount -n -o remount,ro dummydev /");
run("/bin/mount -n -o remount,ro /");
_e("PID %d: %s ...", getpid(), sig == SIGINT || sig == SIGUSR1 ? "Rebooting" : "Halting");
do_sleep(5);
_d("%s.", sig == SIGINT || sig == SIGUSR1 ? "Rebooting" : "Halting");
if (sig == SIGINT || sig == SIGUSR1)
reboot(RB_AUTOBOOT);
reboot(RB_POWER_OFF);
reboot(RB_HALT_SYSTEM); /* Eh, what? Should not get here ... */
}
/*