command line, initialize singlemount's rc to an error value so it doesn't think it succeeded when it didn't, use absolute path when associating a loop device (and the previous FEATURE_CLEAN_UP logic related to that was freeing the wrong thing), move reading of /proc/filesystems to where we can re-read it (when it's empty) for every entry on a "mount -a" so that when /proc is mounted as the first entry, the later filesystems can autodetect filesystem type.
555 lines
13 KiB
C
555 lines
13 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini mount implementation for busybox
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*
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* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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* Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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/* todo:
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* bb_getopt_ulflags();
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*/
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/* Design notes: There is no spec for this. Remind me to write one.
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mount_main() calls singlemount() which calls mount_it_now().
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mount_main() can loop through /etc/fstab for mount -a
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singlemount() can loop through /etc/filesystems for fstype detection.
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mount_it_now() does the actual mount.
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*/
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#include <limits.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <stdio.h>
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#include <mntent.h>
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#include <ctype.h>
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#include <sys/mount.h>
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#include <fcntl.h> // for CONFIG_FEATURE_MOUNT_LOOP
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#include <sys/ioctl.h> // for CONFIG_FEATURE_MOUNT_LOOP
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#include "busybox.h"
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// These two aren't always defined in old headers
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#ifndef MS_BIND
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#define MS_BIND 4096
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#endif
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#ifndef MS_MOVE
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#define MS_MOVE 8192
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#endif
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#ifndef MS_SILENT
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#define MS_SILENT 32768
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#endif
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// Not real flags, but we want to be able to check for this.
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#define MOUNT_NOAUTO (1<<29)
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#define MOUNT_SWAP (1<<30)
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/* Standard mount options (from -o options or --options), with corresponding
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* flags */
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struct {
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const char *name;
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long flags;
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} static const mount_options[] = {
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// NOP flags.
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{"loop", 0},
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{"defaults", 0},
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{"quiet", 0},
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// vfs flags
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{"ro", MS_RDONLY},
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{"rw", ~MS_RDONLY},
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{"nosuid", MS_NOSUID},
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{"suid", ~MS_NOSUID},
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{"dev", ~MS_NODEV},
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{"nodev", MS_NODEV},
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{"exec", ~MS_NOEXEC},
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{"noexec", MS_NOEXEC},
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{"sync", MS_SYNCHRONOUS},
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{"async", ~MS_SYNCHRONOUS},
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{"atime", ~MS_NOATIME},
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{"noatime", MS_NOATIME},
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{"diratime", ~MS_NODIRATIME},
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{"nodiratime", MS_NODIRATIME},
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{"loud", ~MS_SILENT},
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// action flags
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{"remount", MS_REMOUNT},
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{"bind", MS_BIND},
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{"move", MS_MOVE},
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{"noauto",MOUNT_NOAUTO},
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{"swap",MOUNT_SWAP}
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};
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/* Append mount options to string */
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static void append_mount_options(char **oldopts, char *newopts)
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{
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if(*oldopts && **oldopts) {
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char *temp=bb_xasprintf("%s,%s",*oldopts,newopts);
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free(*oldopts);
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*oldopts=temp;
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} else {
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if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
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*oldopts = bb_xstrdup(newopts);
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}
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}
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/* Use the mount_options list to parse options into flags.
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* Return list of unrecognized options in *strflags if strflags!=NULL */
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static int parse_mount_options(char *options, char **unrecognized)
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{
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int flags = MS_SILENT;
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// Loop through options
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for (;;) {
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int i;
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char *comma = strchr(options, ',');
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if (comma) *comma = 0;
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// Find this option in mount_options
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for (i = 0; i < (sizeof(mount_options) / sizeof(*mount_options)); i++) {
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if (!strcasecmp(mount_options[i].name, options)) {
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long fl = mount_options[i].flags;
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if(fl < 0) flags &= fl;
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else flags |= fl;
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break;
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}
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}
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// If unrecognized not NULL, append unrecognized mount options */
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if (unrecognized
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&& i == (sizeof(mount_options) / sizeof(*mount_options)))
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{
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// Add it to strflags, to pass on to kernel
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i = *unrecognized ? strlen(*unrecognized) : 0;
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*unrecognized = xrealloc(*unrecognized, i+strlen(options)+2);
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// Comma separated if it's not the first one
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if (i) (*unrecognized)[i++] = ',';
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strcpy((*unrecognized)+i, options);
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}
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// Advance to next option, or finish
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if(comma) {
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*comma = ',';
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options = ++comma;
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} else break;
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}
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return flags;
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}
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// Return a list of all block device backed filesystems
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static llist_t *get_block_backed_filesystems(void)
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{
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char *fs, *buf,
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*filesystems[] = {"/etc/filesystems", "/proc/filesystems", 0};
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llist_t *list = 0;
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int i;
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FILE *f;
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for(i = 0; filesystems[i]; i++) {
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if(!(f = fopen(filesystems[i], "r"))) continue;
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for(fs = buf = 0; (fs = buf = bb_get_chomped_line_from_file(f));
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free(buf))
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{
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if(!strncmp(buf,"nodev",5) && isspace(buf[5])) continue;
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while(isspace(*fs)) fs++;
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if(*fs=='#' || *fs=='*') continue;
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if(!*fs) continue;
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list=llist_add_to_end(list,bb_xstrdup(fs));
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}
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if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
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}
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return list;
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}
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llist_t *fslist = 0;
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void delete_block_backed_filesystems(void);
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#if ENABLE_FEATURE_CLEAN_UP
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static void delete_block_backed_filesystems(void)
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{
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llist_free(fslist);
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}
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#endif
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#if ENABLE_FEATURE_MTAB_SUPPORT
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static int useMtab;
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#else
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#define useMtab 0
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#endif
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// Perform actual mount of specific filesystem at specific location.
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static int mount_it_now(struct mntent *mp, int vfsflags)
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{
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int rc;
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char *filteropts = 0;
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parse_mount_options(mp->mnt_opts, &filteropts);
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// Mount, with fallback to read-only if necessary.
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for(;;) {
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rc = mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
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vfsflags, filteropts);
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if(!rc || (vfsflags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
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break;
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bb_error_msg("%s is write-protected, mounting read-only",
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mp->mnt_fsname);
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vfsflags |= MS_RDONLY;
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}
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free(filteropts);
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// Abort entirely if permission denied.
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if (rc && errno == EPERM)
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bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
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/* If the mount was successful, and we're maintaining an old-style
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* mtab file by hand, add the new entry to it now. */
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if(ENABLE_FEATURE_MTAB_SUPPORT && useMtab && !rc) {
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FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
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int i;
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if(!mountTable)
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bb_error_msg("No %s\n",bb_path_mtab_file);
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// Add vfs string flags
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for(i=0; mount_options[i].flags != MS_REMOUNT; i++)
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if (mount_options[i].flags > 0)
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append_mount_options(&(mp->mnt_opts),
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// Shut up about the darn const. It's not important. I don't care.
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(char *)mount_options[i].name);
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// Remove trailing / (if any) from directory we mounted on
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i = strlen(mp->mnt_dir);
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if(i>1 && mp->mnt_dir[i-1] == '/') mp->mnt_dir[i-1] = 0;
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// Write and close.
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if(!mp->mnt_type || !*mp->mnt_type) mp->mnt_type="--bind";
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addmntent(mountTable, mp);
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endmntent(mountTable);
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if (ENABLE_FEATURE_CLEAN_UP)
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if(strcmp(mp->mnt_type,"--bind")) mp->mnt_type = 0;
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}
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return rc;
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}
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// Mount one directory. Handles NFS, loopback, autobind, and filesystem type
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// detection. Returns 0 for success, nonzero for failure.
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static int singlemount(struct mntent *mp)
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{
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int rc = 1, vfsflags;
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char *loopFile = 0;
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llist_t *fl = 0;
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struct stat st;
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vfsflags = parse_mount_options(mp->mnt_opts, 0);
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// Treat fstype "auto" as unspecified.
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if (mp->mnt_type && !strcmp(mp->mnt_type,"auto")) mp->mnt_type = 0;
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// Might this be an NFS filesystem?
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if (ENABLE_FEATURE_MOUNT_NFS &&
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(!mp->mnt_type || !strcmp(mp->mnt_type,"nfs")) &&
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strchr(mp->mnt_fsname, ':') != NULL)
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{
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char *options=0;
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parse_mount_options(mp->mnt_opts, &options);
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if (nfsmount(mp->mnt_fsname, mp->mnt_dir, &vfsflags, &options, 1)) {
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bb_perror_msg("nfsmount failed");
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return 1;
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}
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// Strangely enough, nfsmount() doesn't actually mount() anything.
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else return mount_it_now(mp, vfsflags);
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}
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// Look at the file. (Not found isn't a failure for remount.)
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if (lstat(mp->mnt_fsname, &st));
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if (!(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))) {
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// Do we need to allocate a loopback device for it?
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if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
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loopFile = bb_simplify_path(mp->mnt_fsname);
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mp->mnt_fsname = 0;
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switch(set_loop(&(mp->mnt_fsname), loopFile, 0)) {
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case 0:
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case 1:
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break;
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default:
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bb_error_msg( errno == EPERM || errno == EACCES
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? bb_msg_perm_denied_are_you_root
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: "Couldn't setup loop device");
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return errno;
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}
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// Autodetect bind mounts
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} else if (S_ISDIR(st.st_mode) && !mp->mnt_type) vfsflags |= MS_BIND;
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}
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/* If we know the fstype (or don't need to), jump straight
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* to the actual mount. */
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if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
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rc = mount_it_now(mp, vfsflags);
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// Loop through filesystem types until mount succeeds or we run out
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else {
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/* Initialize list of block backed filesystems. This has to be
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* done here so that during "mount -a", mounts after /proc shows up
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* can autodetect. */
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if (!fslist) {
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fslist = get_block_backed_filesystems();
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if (ENABLE_FEATURE_CLEAN_UP && fslist)
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atexit(delete_block_backed_filesystems);
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}
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for (fl = fslist; fl; fl = fl->link) {
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mp->mnt_type = fl->data;
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if (!(rc = mount_it_now(mp,vfsflags))) break;
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mp->mnt_type = 0;
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}
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}
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// Mount failed. Clean up
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if (rc && loopFile) {
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del_loop(mp->mnt_fsname);
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if(ENABLE_FEATURE_CLEAN_UP) {
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free(loopFile);
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free(mp->mnt_fsname);
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}
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}
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return rc;
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}
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// Parse options, if necessary parse fstab/mtab, and call singlemount for
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// each directory to be mounted.
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int mount_main(int argc, char **argv)
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{
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char *cmdopts = bb_xstrdup(""), *fstabname, *fstype=0, *storage_path=0;
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FILE *fstab;
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int i, opt, all = FALSE, rc = 1;
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struct mntent mtpair[2], *mtcur = mtpair;
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/* parse long options, like --bind and --move. Note that -o option
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* and --option are synonymous. Yes, this means --remount,rw works. */
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for (i = opt = 0; i < argc; i++) {
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if (argv[i][0] == '-' && argv[i][1] == '-') {
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append_mount_options(&cmdopts,argv[i]+2);
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} else argv[opt++] = argv[i];
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}
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argc = opt;
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// Parse remaining options
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while ((opt = getopt(argc, argv, "o:t:rwavnf")) > 0) {
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switch (opt) {
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case 'o':
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append_mount_options(&cmdopts, optarg);
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break;
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case 't':
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fstype = optarg;
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break;
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case 'r':
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append_mount_options(&cmdopts, "ro");
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break;
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case 'w':
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append_mount_options(&cmdopts, "rw");
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break;
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case 'a':
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all = TRUE;
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break;
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case 'n':
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USE_FEATURE_MTAB_SUPPORT(useMtab = FALSE;)
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break;
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case 'f':
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USE_FEATURE_MTAB_SUPPORT(fakeIt = FALSE;)
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break;
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case 'v':
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break; // ignore -v
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default:
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bb_show_usage();
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}
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}
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// Three or more non-option arguments? Die with a usage message.
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if (optind-argc>2) bb_show_usage();
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// If we have no arguments, show currently mounted filesystems
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if (optind == argc) {
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if (!all) {
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FILE *mountTable = setmntent(bb_path_mtab_file, "r");
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if(!mountTable) bb_error_msg_and_die("No %s",bb_path_mtab_file);
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while (getmntent_r(mountTable,mtpair,bb_common_bufsiz1,
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sizeof(bb_common_bufsiz1)))
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{
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// Don't show rootfs.
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if (!strcmp(mtpair->mnt_fsname, "rootfs")) continue;
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if (!fstype || !strcmp(mtpair->mnt_type, fstype))
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printf("%s on %s type %s (%s)\n", mtpair->mnt_fsname,
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mtpair->mnt_dir, mtpair->mnt_type,
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mtpair->mnt_opts);
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}
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if (ENABLE_FEATURE_CLEAN_UP) endmntent(mountTable);
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return EXIT_SUCCESS;
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}
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}
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// When we have two arguments, the second is the directory and we can
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// skip looking at fstab entirely. We can always abspath() the directory
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// argument when we get it.
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if (optind+2 == argc) {
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mtpair->mnt_fsname = argv[optind];
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mtpair->mnt_dir = argv[optind+1];
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mtpair->mnt_type = fstype;
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mtpair->mnt_opts = cmdopts;
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rc = singlemount(mtpair);
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goto clean_up;
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}
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// If we have at least one argument, it's the storage location
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if (optind < argc) storage_path = bb_simplify_path(argv[optind]);
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// Open either fstab or mtab
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if (parse_mount_options(cmdopts,0) & MS_REMOUNT)
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fstabname = (char *)bb_path_mtab_file; // Again with the evil const.
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else fstabname="/etc/fstab";
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|
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if (!(fstab=setmntent(fstabname,"r")))
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bb_perror_msg_and_die("Cannot read %s",fstabname);
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// Loop through entries until we find what we're looking for.
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memset(mtpair,0,sizeof(mtpair));
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for (;;) {
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struct mntent *mtnext = mtpair + (mtcur==mtpair ? 1 : 0);
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// Get next fstab entry
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|
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if (!getmntent_r(fstab, mtcur, bb_common_bufsiz1,
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sizeof(bb_common_bufsiz1)))
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{
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// Were we looking for something specific?
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|
|
if (optind != argc) {
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|
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// If we didn't find anything, complain.
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|
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if (!mtnext->mnt_fsname)
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bb_error_msg_and_die("Can't find %s in %s",
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argv[optind], fstabname);
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// Mount the last thing we found.
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mtcur = mtnext;
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mtcur->mnt_opts=bb_xstrdup(mtcur->mnt_opts);
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append_mount_options(&(mtcur->mnt_opts),cmdopts);
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rc = singlemount(mtcur);
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free(mtcur->mnt_opts);
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}
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break;
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}
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/* If we're trying to mount something specific and this isn't it,
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* skip it. Note we must match both the exact text in fstab (ala
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* "proc") or a full path from root */
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|
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if (optind != argc) {
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// Is this what we're looking for?
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if(strcmp(argv[optind],mtcur->mnt_fsname) &&
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strcmp(storage_path,mtcur->mnt_fsname) &&
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strcmp(argv[optind],mtcur->mnt_dir) &&
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strcmp(storage_path,mtcur->mnt_dir)) continue;
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// Remember this entry. Something later may have overmounted
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// it, and we want the _last_ match.
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mtcur = mtnext;
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// If we're mounting all.
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|
} else {
|
|
|
|
// Do we need to match a filesystem type?
|
|
if (fstype && strcmp(mtcur->mnt_type,fstype)) continue;
|
|
|
|
// Skip noauto and swap anyway.
|
|
|
|
if (parse_mount_options(mtcur->mnt_opts,0)
|
|
& (MOUNT_NOAUTO | MOUNT_SWAP)) continue;
|
|
|
|
// Mount this thing.
|
|
|
|
rc = singlemount(mtcur);
|
|
if (rc) {
|
|
// Don't whine about already mounted fs when mounting all.
|
|
if (errno == EBUSY) rc = 0;
|
|
else break;
|
|
}
|
|
}
|
|
}
|
|
if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);
|
|
|
|
clean_up:
|
|
|
|
if (ENABLE_FEATURE_CLEAN_UP) {
|
|
free(storage_path);
|
|
free(cmdopts);
|
|
free(fstype);
|
|
}
|
|
|
|
if(rc)
|
|
bb_perror_msg("Mounting %s on %s failed",
|
|
mtcur->mnt_fsname, mtcur->mnt_dir);
|
|
|
|
return rc;
|
|
}
|