| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini umount implementation for busybox |
| * |
| * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
| * Copyright (C) 2005 by Rob Landley <rob@landley.net> |
| * |
| * Licensed under GPLv2, see file LICENSE in this source tree. |
| */ |
| #include <mntent.h> |
| #include <sys/mount.h> |
| /* Make sure we have all the new mount flags we actually try to use. */ |
| #ifndef MS_BIND |
| # define MS_BIND (1 << 12) |
| #endif |
| #ifndef MS_MOVE |
| # define MS_MOVE (1 << 13) |
| #endif |
| #ifndef MS_RECURSIVE |
| # define MS_RECURSIVE (1 << 14) |
| #endif |
| #ifndef MS_SILENT |
| # define MS_SILENT (1 << 15) |
| #endif |
| /* The shared subtree stuff, which went in around 2.6.15. */ |
| #ifndef MS_UNBINDABLE |
| # define MS_UNBINDABLE (1 << 17) |
| #endif |
| #ifndef MS_PRIVATE |
| # define MS_PRIVATE (1 << 18) |
| #endif |
| #ifndef MS_SLAVE |
| # define MS_SLAVE (1 << 19) |
| #endif |
| #ifndef MS_SHARED |
| # define MS_SHARED (1 << 20) |
| #endif |
| #ifndef MS_RELATIME |
| # define MS_RELATIME (1 << 21) |
| #endif |
| #include "libbb.h" |
| |
| |
| #if defined(__dietlibc__) |
| /* 16.12.2006, Sampo Kellomaki (sampo@iki.fi) |
| * dietlibc-0.30 does not have implementation of getmntent_r() */ |
| static struct mntent *getmntent_r(FILE* stream, struct mntent* result, |
| char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM) |
| { |
| struct mntent* ment = getmntent(stream); |
| return memcpy(result, ment, sizeof(*ment)); |
| } |
| #endif |
| |
| /* ignored: -v -d -t -i */ |
| #define OPTION_STRING "fldnra" "vdt:i" |
| #define OPT_FORCE (1 << 0) |
| #define OPT_LAZY (1 << 1) |
| #define OPT_FREELOOP (1 << 2) |
| #define OPT_NO_MTAB (1 << 3) |
| #define OPT_REMOUNT (1 << 4) |
| #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? (1 << 5) : 0) |
| |
| // These constants from linux/fs.h must match OPT_FORCE and OPT_LAZY, |
| // otherwise "doForce" trick below won't work! |
| //#define MNT_FORCE 0x00000001 /* Attempt to forcibly umount */ |
| //#define MNT_DETACH 0x00000002 /* Just detach from the tree */ |
| |
| int umount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int umount_main(int argc UNUSED_PARAM, char **argv) |
| { |
| int doForce; |
| char *const buf = xmalloc(4096); /* reducing stack usage */ |
| struct mntent me; |
| FILE *fp; |
| char *fstype = NULL; |
| int status = EXIT_SUCCESS; |
| unsigned opt; |
| struct mtab_list { |
| char *dir; |
| char *device; |
| struct mtab_list *next; |
| } *mtl, *m; |
| |
| opt = getopt32(argv, OPTION_STRING, &fstype); |
| //argc -= optind; |
| argv += optind; |
| doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY)); |
| |
| /* Get a list of mount points from mtab. We read them all in now mostly |
| * for umount -a (so we don't have to worry about the list changing while |
| * we iterate over it, or about getting stuck in a loop on the same failing |
| * entry. Notice that this also naturally reverses the list so that -a |
| * umounts the most recent entries first. */ |
| m = mtl = NULL; |
| |
| // If we're umounting all, then m points to the start of the list and |
| // the argument list should be empty (which will match all). |
| fp = setmntent(bb_path_mtab_file, "r"); |
| if (!fp) { |
| if (opt & OPT_ALL) |
| bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file); |
| } else { |
| while (getmntent_r(fp, &me, buf, 4096)) { |
| /* Match fstype if passed */ |
| if (!match_fstype(&me, fstype)) |
| continue; |
| m = xzalloc(sizeof(*m)); |
| m->next = mtl; |
| m->device = xstrdup(me.mnt_fsname); |
| m->dir = xstrdup(me.mnt_dir); |
| mtl = m; |
| } |
| endmntent(fp); |
| } |
| |
| // If we're not umounting all, we need at least one argument. |
| if (!(opt & OPT_ALL) && !fstype) { |
| if (!argv[0]) |
| bb_show_usage(); |
| m = NULL; |
| } |
| |
| // Loop through everything we're supposed to umount, and do so. |
| for (;;) { |
| int curstat; |
| char *zapit = *argv; |
| char *path; |
| |
| // Do we already know what to umount this time through the loop? |
| if (m) |
| path = xstrdup(m->dir); |
| // For umount -a, end of mtab means time to exit. |
| else if (opt & OPT_ALL) |
| break; |
| // Use command line argument (and look it up in mtab list) |
| else { |
| if (!zapit) |
| break; |
| argv++; |
| path = xmalloc_realpath(zapit); |
| if (path) { |
| for (m = mtl; m; m = m->next) |
| if (strcmp(path, m->dir) == 0 || strcmp(path, m->device) == 0) |
| 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(zapit); |
| |
| // Force the unmount, if necessary. |
| if (curstat && doForce) |
| curstat = umount2(zapit, doForce); |
| |
| // If still can't umount, maybe remount read-only? |
| if (curstat) { |
| if ((opt & OPT_REMOUNT) && errno == EBUSY && m) { |
| // Note! Even if we succeed here, later we should not |
| // free loop device or erase mtab entry! |
| const char *msg = "%s busy - remounted read-only"; |
| curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL); |
| if (curstat) { |
| msg = "can't remount %s read-only"; |
| status = EXIT_FAILURE; |
| } |
| bb_error_msg(msg, m->device); |
| } else { |
| status = EXIT_FAILURE; |
| bb_perror_msg("can't %sumount %s", (doForce ? "forcibly " : ""), zapit); |
| } |
| } else { |
| // De-allocate the loop device. This ioctl should be ignored on |
| // any non-loop block devices. |
| if (ENABLE_FEATURE_MOUNT_LOOP && (opt & OPT_FREELOOP) && m) |
| del_loop(m->device); |
| if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m) |
| 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. |
| if (m) { |
| while ((m = m->next) != NULL) |
| // NB: if m is non-NULL, path is non-NULL as well |
| if ((opt & OPT_ALL) || strcmp(path, m->device) == 0) |
| break; |
| } |
| free(path); |
| } |
| |
| // Free mtab list if necessary |
| if (ENABLE_FEATURE_CLEAN_UP) { |
| while (mtl) { |
| m = mtl->next; |
| free(mtl->device); |
| free(mtl->dir); |
| free(mtl); |
| mtl = m; |
| } |
| free(buf); |
| } |
| |
| return status; |
| } |