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    Contents of /trunk/mkinitrd-magellan/busybox/util-linux/umount.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 9 months ago) by niro
    File MIME type: text/plain
    File size: 4161 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 /* vi: set sw=4 ts=4: */
    2 /*
    3 * Mini umount implementation for busybox
    4 *
    5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
    6 * Copyright (C) 2005 by Rob Landley <rob@landley.net>
    7 *
    8 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
    9 */
    10
    11 #include "busybox.h"
    12 #include <mntent.h>
    13 #include <getopt.h>
    14
    15 #define OPTION_STRING "flDnravd"
    16 #define OPT_FORCE 1
    17 #define OPT_LAZY 2
    18 #define OPT_DONTFREELOOP 4
    19 #define OPT_NO_MTAB 8
    20 #define OPT_REMOUNT 16
    21 #define OPT_ALL (ENABLE_FEATURE_UMOUNT_ALL ? 32 : 0)
    22
    23 int umount_main(int argc, char **argv)
    24 {
    25 int doForce;
    26 char path[2*PATH_MAX];
    27 struct mntent me;
    28 FILE *fp;
    29 int status = EXIT_SUCCESS;
    30 unsigned opt;
    31 struct mtab_list {
    32 char *dir;
    33 char *device;
    34 struct mtab_list *next;
    35 } *mtl, *m;
    36
    37 /* Parse any options */
    38
    39 opt = getopt32(argc, argv, OPTION_STRING);
    40
    41 argc -= optind;
    42 argv += optind;
    43
    44 doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
    45
    46 /* Get a list of mount points from mtab. We read them all in now mostly
    47 * for umount -a (so we don't have to worry about the list changing while
    48 * we iterate over it, or about getting stuck in a loop on the same failing
    49 * entry. Notice that this also naturally reverses the list so that -a
    50 * umounts the most recent entries first. */
    51
    52 m = mtl = 0;
    53
    54 /* If we're umounting all, then m points to the start of the list and
    55 * the argument list should be empty (which will match all). */
    56
    57 fp = setmntent(bb_path_mtab_file, "r");
    58 if (!fp) {
    59 if (opt & OPT_ALL)
    60 bb_error_msg_and_die("cannot open %s", bb_path_mtab_file);
    61 } else {
    62 while (getmntent_r(fp, &me, path, sizeof(path))) {
    63 m = xmalloc(sizeof(struct mtab_list));
    64 m->next = mtl;
    65 m->device = xstrdup(me.mnt_fsname);
    66 m->dir = xstrdup(me.mnt_dir);
    67 mtl = m;
    68 }
    69 endmntent(fp);
    70 }
    71
    72 /* If we're not umounting all, we need at least one argument. */
    73 if (!(opt & OPT_ALL)) {
    74 m = 0;
    75 if (!argc) bb_show_usage();
    76 }
    77
    78 // Loop through everything we're supposed to umount, and do so.
    79 for (;;) {
    80 int curstat;
    81 char *zapit = *argv;
    82
    83 // Do we already know what to umount this time through the loop?
    84 if (m) safe_strncpy(path, m->dir, PATH_MAX);
    85 // For umount -a, end of mtab means time to exit.
    86 else if (opt & OPT_ALL) break;
    87 // Get next command line argument (and look it up in mtab list)
    88 else if (!argc--) break;
    89 else {
    90 argv++;
    91 realpath(zapit, path);
    92 for (m = mtl; m; m = m->next)
    93 if (!strcmp(path, m->dir) || !strcmp(path, m->device))
    94 break;
    95 }
    96 // If we couldn't find this sucker in /etc/mtab, punt by passing our
    97 // command line argument straight to the umount syscall. Otherwise,
    98 // umount the directory even if we were given the block device.
    99 if (m) zapit = m->dir;
    100
    101 // Let's ask the thing nicely to unmount.
    102 curstat = umount(zapit);
    103
    104 // Force the unmount, if necessary.
    105 if (curstat && doForce) {
    106 curstat = umount2(zapit, doForce);
    107 if (curstat)
    108 bb_error_msg("forced umount of %s failed!", zapit);
    109 }
    110
    111 // If still can't umount, maybe remount read-only?
    112 if (curstat && (opt & OPT_REMOUNT) && errno == EBUSY && m) {
    113 curstat = mount(m->device, zapit, NULL, MS_REMOUNT|MS_RDONLY, NULL);
    114 bb_error_msg(curstat ? "cannot remount %s read-only" :
    115 "%s busy - remounted read-only", m->device);
    116 }
    117
    118 if (curstat) {
    119 status = EXIT_FAILURE;
    120 bb_perror_msg("cannot umount %s", zapit);
    121 } else {
    122 /* De-allocate the loop device. This ioctl should be ignored on
    123 * any non-loop block devices. */
    124 if (ENABLE_FEATURE_MOUNT_LOOP && !(opt & OPT_DONTFREELOOP) && m)
    125 del_loop(m->device);
    126 if (ENABLE_FEATURE_MTAB_SUPPORT && !(opt & OPT_NO_MTAB) && m)
    127 erase_mtab(m->dir);
    128 }
    129
    130 // Find next matching mtab entry for -a or umount /dev
    131 // Note this means that "umount /dev/blah" will unmount all instances
    132 // of /dev/blah, not just the most recent.
    133 while (m && (m = m->next))
    134 if ((opt & OPT_ALL) || !strcmp(path, m->device))
    135 break;
    136 }
    137
    138 // Free mtab list if necessary
    139
    140 if (ENABLE_FEATURE_CLEAN_UP) {
    141 while (mtl) {
    142 m = mtl->next;
    143 free(mtl->device);
    144 free(mtl->dir);
    145 free(mtl);
    146 mtl = m;
    147 }
    148 }
    149
    150 return status;
    151 }