diff options
| -rw-r--r-- | toys/lsb/umount.c | 84 |
1 files changed, 56 insertions, 28 deletions
diff --git a/toys/lsb/umount.c b/toys/lsb/umount.c index d1a2c69d..002ffd68 100644 --- a/toys/lsb/umount.c +++ b/toys/lsb/umount.c @@ -8,7 +8,7 @@ * nor per-process mount namespaces can work sanely with mtab. The kernel * tracks mount points now, a userspace application can't do so anymore. -USE_UMOUNT(NEWTOY(umount, "ndDflrat*v", TOYFLAG_BIN|TOYFLAG_STAYROOT)) +USE_UMOUNT(NEWTOY(umount, "ndDflrat*v[!na]", TOYFLAG_BIN|TOYFLAG_STAYROOT)) config UMOUNT bool "umount" @@ -19,11 +19,12 @@ config UMOUNT Unmount the listed filesystems. -a Unmount all mounts in /proc/mounts instead of command line list - -t Restrict "all" to mounts of TYPE (or use "noTYPE" to skip) -D Don't free loopback device(s). -f Force unmount. -l Lazy unmount (detach from filesystem now, close when last user does). + -n Don't use /proc/mounts -r Remount read only if unmounting fails. + -t Restrict "all" to mounts of TYPE (or use "noTYPE" to skip) -v Verbose */ @@ -63,19 +64,16 @@ void comma_collate(char **old, char *new) *old = temp; } -void arg_comma_collate(char **old, struct arg_list *arg) -{ - while (arg) { - comma_collate(old, arg->arg); - arg = arg->next; - } -} - +// iterate through strings in a comma separated list. +// returns start of next entry or NULL if none +// sets *len to length of entry (not including comma) +// advances *list to start of next entry char *comma_iterate(char **list, int *len) { char *start = *list, *end; if (!*list) return 0; + if (!(end = strchr(*list, ','))) { *len = strlen(*list); *list = 0; @@ -84,25 +82,42 @@ char *comma_iterate(char **list, int *len) return start; } -static void do_umount(char *dir, int flags) +static void do_umount(char *dir, char *dev, int flags) { if (!umount2(dir, flags)) { - if (toys.optflags & FLAG_v) printf("%s unmounted", dir); + if (toys.optflags & FLAG_v) xprintf("%s unmounted\n", dir); + + // Attempt to disassociate loopback device. This ioctl should be ignored + // for anything else, because lanana allocated ioctl range 'L' to loopback + if (dev && !(toys.optflags & FLAG_D)) { + int lfd = open(dev, O_RDONLY); + + if (lfd != -1) { + // This is LOOP_CLR_FD, fetching it from headers is awkward + if (!ioctl(lfd, 0x4C01) && (toys.optflags & FLAG_v)) + xprintf("%s cleared\n", dev); + close(lfd); + } + } + return; } + if (toys.optflags & FLAG_r) { if (!mount("", dir, "", MS_REMOUNT|MS_RDONLY, "")) { - if (toys.optflags & FLAG_v) printf("%s remounted ro", dir); + if (toys.optflags & FLAG_v) xprintf("%s remounted ro\n", dir); return; } } + perror_msg("%s", dir); } void umount_main(void) { + char **optargs, *pm = "/proc/mounts"; + struct mtab_list *mlsave = 0, *mlrev = 0, *ml; int flags=0; - char **optargs; if (!toys.optc && !(toys.optflags & FLAG_a)) error_exit("Need 1 arg or -a"); @@ -110,27 +125,26 @@ void umount_main(void) if (toys.optflags & FLAG_f) flags |= MNT_FORCE; if (toys.optflags & FLAG_l) flags |= MNT_DETACH; - for (optargs = toys.optargs; *optargs; optargs++) do_umount(*optargs, flags); + // Load /proc/mounts and get a reversed list (newest first) + // We use the list both for -a, and to umount /dev/name or do losetup -d + if (!(toys.optflags & FLAG_n) && !access(pm, R_OK)) + mlrev = dlist_terminate(mlsave = xgetmountlist(pm)); + // Unmount all: loop through mounted filesystems, skip -t, unmount the rest if (toys.optflags & FLAG_a) { - struct mtab_list *mlsave, *ml; char *typestr = 0; - - if (TT.t) arg_comma_collate(&typestr, TT.t); - - // Loop through mounted filesystems - mlsave = xgetmountlist(0); - ml = ml->prev; - - for (ml = dlist_terminate(mlsave); ml; ml = ml->prev) { - if (TT.t) { + struct arg_list *tal; + + for (tal = TT.t; tal; tal = tal->next) comma_collate(&typestr, tal->arg); + for (ml = mlrev; ml; ml = ml->prev) { + if (typestr) { char *type, *types = typestr; int len, skip = strncmp(types, "no", 2); - // Loop through -t filters for (;;) { if (!(type = comma_iterate(&types, &len))) break; if (!skip) { + // If one -t starts with "no", the rest must too if (strncmp(type, "no", 2)) error_exit("bad -t"); if (!strncmp(type+2, ml->type, len-2)) { skip = 1; @@ -143,13 +157,27 @@ void umount_main(void) } if (skip) continue; } - do_umount(ml->dir, flags); + + do_umount(ml->dir, ml->device, flags); } if (CFG_TOYBOX_FREE) { free(typestr); llist_traverse(mlsave, free); } + // TODO: under what circumstances do we umount non-absolute path? + } else for (optargs = toys.optargs; *optargs; optargs++) { + char *abs = xabspath(*optargs, 0); + + for (ml = abs ? mlrev : 0; ml; ml = ml->prev) { + if (!strcmp(ml->dir, abs)) break; + if (!strcmp(ml->device, abs)) { + free(abs); + abs = ml->dir; + break; + } + } - return; + do_umount(abs ? abs : *optargs, ml ? ml->device : 0, flags); + if (ml && abs != ml->dir) free(abs); } } |