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authorRob Landley <rob@landley.net>2006-08-17 19:07:20 +0000
committerRob Landley <rob@landley.net>2006-08-17 19:07:20 +0000
commit4470b74e29f98ffdd39acf8085e5b7cd0758edaa (patch)
treebf8214dbd36de26f10c48bd2f2811aab6eebc643
parenteb28ce46448e280742465d027e86701766c34d97 (diff)
downloadbusybox-4470b74e29f98ffdd39acf8085e5b7cd0758edaa.tar.gz
The kernel can't handle umount /dev/hdc, we have to do it through mtab,
except that we still have to work when there is no mtab. Oh, and while we're at it, take advantage of the fact that modern processors avoid branches via conditional assignment where possible. ("x = a ? b : c;" turns into "x = c; if (a) x = b;" because that way there's no branch to potentially mispredict and thus never a bubble in the pipeline. The if(a) turns into an assembly test followed by a conditional assignment (rather than a conditional jump).) So since the compiler is going to do that _anyway_, we might as well take advantage of it to produce a slightly smaller binary. So there.
-rw-r--r--util-linux/umount.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/util-linux/umount.c b/util-linux/umount.c
index 24c1d03a9..fabc3d049 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -78,6 +78,7 @@ int umount_main(int argc, char **argv)
// Loop through everything we're supposed to umount, and do so.
for (;;) {
int curstat;
+ char *zapit = *argv;
// Do we already know what to umount this time through the loop?
if (m) safe_strncpy(path, m->dir, PATH_MAX);
@@ -86,32 +87,37 @@ int umount_main(int argc, char **argv)
// Get next command line argument (and look it up in mtab list)
else if (!argc--) break;
else {
- realpath(*argv++, path);
+ argv++;
+ realpath(zapit, path);
for (m = mtl; m; m = m->next)
if (!strcmp(path, m->dir) || !strcmp(path, m->device))
break;
}
+ // If we couldn't find this sucker in /etc/mtab, punt by passing our
+ // command line argument straight to the umount syscall. Otherwise,
+ // umount the directory even if we were given the block device.
+ if (m) zapit = m->dir;
// Let's ask the thing nicely to unmount.
- curstat = umount(path);
+ curstat = umount(zapit);
// Force the unmount, if necessary.
if (curstat && doForce) {
- curstat = umount2(path, doForce);
+ curstat = umount2(zapit, doForce);
if (curstat)
- bb_error_msg_and_die("forced umount of %s failed!", path);
+ bb_error_msg_and_die("forced umount of %s failed!", zapit);
}
// If still can't umount, maybe remount read-only?
if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
- curstat = mount(m->device, path, NULL, MS_REMOUNT|MS_RDONLY, NULL);
+ curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
bb_error_msg(curstat ? "Cannot remount %s read-only" :
"%s busy - remounted read-only", m->device);
}
if (curstat) {
status = EXIT_FAILURE;
- bb_perror_msg("Couldn't umount %s", path);
+ bb_perror_msg("Couldn't umount %s", zapit);
} else {
/* De-allocate the loop device. This ioctl should be ignored on
* any non-loop block devices. */
@@ -121,9 +127,9 @@ int umount_main(int argc, char **argv)
erase_mtab(m->dir);
}
-
-
// Find next matching mtab entry for -a or umount /dev
+ // Note this means that "umount /dev/blah" will unmount all instances
+ // of /dev/blah, not just the most recent.
while (m && (m = m->next))
if ((opt & OPT_ALL) || !strcmp(path,m->device))
break;