/* 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 ATTRIBUTE_UNUSED, int bufsize ATTRIBUTE_UNUSED) { 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 ATTRIBUTE_UNUSED, 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("cannot 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 = "cannot remount %s read-only"; status = EXIT_FAILURE; } bb_error_msg(msg, m->device); } else { status = EXIT_FAILURE; bb_perror_msg("cannot %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; }