/* 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> * * This program is licensed under the GNU General Public license (GPL) * version 2 or later, see http://www.fsf.org/licensing/licenses/gpl.html * or the file "LICENSE" in the busybox source tarball for the full text. * */ #include <limits.h> #include <stdio.h> #include <mntent.h> #include <errno.h> #include <string.h> #include <stdlib.h> #include <sys/mount.h> #include <getopt.h> #include "busybox.h" #define OPTION_STRING "flDnrvad" #define OPT_FORCE 1 #define OPT_LAZY 2 #define OPT_DONTFREELOOP 4 #define OPT_NO_MTAB 8 #define OPT_REMOUNT 16 #define OPT_IGNORED 32 // -v is ignored #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 64 : 0) int umount_main(int argc, char **argv) { int doForce; char path[2*PATH_MAX]; struct mntent me; FILE *fp; int status = EXIT_SUCCESS; unsigned long opt; struct mtab_list { char *dir; char *device; struct mtab_list *next; } *mtl, *m; /* Parse any options */ opt = bb_getopt_ulflags(argc, argv, OPTION_STRING); 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 = 0; /* 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). */ if (!(fp = setmntent(bb_path_mtab_file, "r"))) { if (opt & OPT_ALL) bb_error_msg_and_die("Cannot open %s", bb_path_mtab_file); } else while (getmntent_r(fp,&me,path,sizeof(path))) { m = xmalloc(sizeof(struct mtab_list)); m->next = mtl; m->device = bb_xstrdup(me.mnt_fsname); m->dir = bb_xstrdup(me.mnt_dir); mtl = m; } endmntent(fp); /* If we're not mounting all, we need at least one argument. */ if (!(opt & OPT_ALL)) { m = 0; if (!argc) bb_show_usage(); } // Loop through everything we're supposed to umount, and do so. for (;;) { int curstat; // 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; // Get next command line argument (and look it up in mtab list) else if (!argc--) break; else { realpath(*argv++, path); for (m = mtl; m; m = m->next) if (!strcmp(path, m->dir) || !strcmp(path, m->device)) break; } // Let's ask the thing nicely to unmount. curstat = umount(path); // Force the unmount, if necessary. if (curstat && doForce) { curstat = umount2(path, doForce); if (curstat) bb_error_msg_and_die("forced umount of %s failed!", path); } // 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); bb_error_msg(curstat ? "Cannot remount %s read-only" : "%s busy - remounted read-only", m->device); } /* De-allocate the loop device. This ioctl should be ignored on any * non-loop block devices. */ if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m) del_loop(m->device); if (curstat) { /* Yes, the ENABLE is redundant here, but the optimizer for ARM * can't do simple constant propagation in local variables... */ if(ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m) erase_mtab(m->dir); status = EXIT_FAILURE; bb_perror_msg("Couldn't umount %s", path); } // Find next matching mtab entry for -a or umount /dev while (m && (m = m->next)) 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; } } return status; }