diff options
Diffstat (limited to 'util-linux/umount.c')
| -rw-r--r-- | util-linux/umount.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/util-linux/umount.c b/util-linux/umount.c new file mode 100644 index 0000000..0662cea --- /dev/null +++ b/util-linux/umount.c @@ -0,0 +1,173 @@ +/* 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 GPL version 2, see file LICENSE in this tarball for details. + */ + +#include <mntent.h> +#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 path = xmalloc(PATH_MAX + 2); /* to save stack */ + 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, path, PATH_MAX)) { + /* Match fstype if passed */ + if (fstype && match_fstype(&me, fstype)) + continue; + m = xmalloc(sizeof(struct mtab_list)); + 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; + + // Do we already know what to umount this time through the loop? + if (m) + safe_strncpy(path, m->dir, PATH_MAX); + // 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++; + 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(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) + if ((opt & OPT_ALL) || !strcmp(path, m->device)) + break; + } + + // 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(path); + } + + return status; +} |