403 lines
11 KiB
C
403 lines
11 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 by Rob Landley <rob@landley.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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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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/* This is just a warning of a common mistake. Possibly this should be a
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* uclibc faq entry rather than in busybox... */
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#if ENABLE_FEATURE_MOUNT_NFS && defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
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#error "You need to build uClibc with UCLIBC_HAS_RPC for busybox mount with NFS support to compile."
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#endif
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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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/* Consume standard mount options (from -o options or --options).
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* Set appropriate flags and collect unrecognized ones as a comma separated
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* string to pass to kernel */
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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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{"loop", 0},
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{"defaults", 0},
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{"noauto", 0},
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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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{"remount", MS_REMOUNT},
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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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{"bind", MS_BIND},
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{"move", MS_MOVE}
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};
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/* Uses the mount_options list above */
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static void parse_mount_options(char *options, int *flags, char **strflags)
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{
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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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// Unrecognized mount option?
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if(i == (sizeof(mount_options) / sizeof(*mount_options))) {
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// Add it to strflags, to pass on to kernel
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i = *strflags ? strlen(*strflags) : 0;
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*strflags = xrealloc(*strflags, i+strlen(options)+2);
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// Comma separated if it's not the first one
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if(i) (*strflags)[i++] = ',';
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strcpy((*strflags)+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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}
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/* This does the work */
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extern int mount_main(int argc, char **argv)
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{
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char *string_flags = 0, *fsType = 0, *blockDevice = 0, *directory = 0,
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*loopFile = 0, *buf = 0,
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*files[] = {"/etc/filesystems", "/proc/filesystems", 0};
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int i, opt, all = FALSE, fakeIt = FALSE, allowWrite = FALSE,
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rc = 1, useMtab = ENABLE_FEATURE_MTAB_SUPPORT;
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int flags=0xc0ed0000; // Needed for linux 2.2, ignored by 2.4 and 2.6.
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FILE *file = 0,*f = 0;
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char path[PATH_MAX*2];
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struct mntent m;
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struct stat statbuf;
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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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parse_mount_options(argv[i]+2, &flags, &string_flags);
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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:rwafnv")) > 0) {
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switch (opt) {
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case 'o':
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parse_mount_options(optarg, &flags, &string_flags);
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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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flags |= MS_RDONLY;
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break;
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case 'w':
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allowWrite=TRUE;
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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 'f':
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fakeIt = TRUE;
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break;
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case 'n':
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useMtab = 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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// If we have no arguments, show currently mounted filesystems
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if(!all && (optind == argc)) {
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FILE *mountTable = setmntent(bb_path_mtab_file, "r");
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if(!mountTable) bb_perror_msg_and_die(bb_path_mtab_file);
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while (getmntent_r(mountTable,&m,path,sizeof(path))) {
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blockDevice = m.mnt_fsname;
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// Clean up display a little bit regarding root devie
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if(!strcmp(blockDevice, "rootfs")) continue;
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if(!strcmp(blockDevice, "/dev/root"))
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blockDevice = find_block_device("/");
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if(!fsType || !strcmp(m.mnt_type, fsType))
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printf("%s on %s type %s (%s)\n", blockDevice, m.mnt_dir,
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m.mnt_type, m.mnt_opts);
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if(ENABLE_FEATURE_CLEAN_UP && blockDevice != m.mnt_fsname)
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free(blockDevice);
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}
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endmntent(mountTable);
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return EXIT_SUCCESS;
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}
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/* The next argument is what to mount. if there's an argument after that
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* it's where to mount it. If we're not mounting all, and we have both
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* of these arguments, jump straight to the actual mount. */
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statbuf.st_mode=0;
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if(optind < argc)
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blockDevice = !stat(argv[optind], &statbuf) ?
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bb_simplify_path(argv[optind]) :
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(ENABLE_FEATURE_CLEAN_UP ? strdup(argv[optind]) : argv[optind]);
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if(optind+1 < argc) directory = bb_simplify_path(argv[optind+1]);
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// If we don't have to loop through fstab, skip ahead a bit.
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if(!all && optind+1!=argc) goto singlemount;
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// Loop through /etc/fstab entries to look up this entry.
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if(!(file=setmntent("/etc/fstab","r")))
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bb_perror_msg_and_die("\nCannot read /etc/fstab");
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for(;;) {
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// Get next fstab entry
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if(!getmntent_r(file,&m,path,sizeof(path))) {
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if(!all)
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bb_perror_msg("Can't find %s in /etc/fstab\n", blockDevice);
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break;
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}
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// If we're mounting all and all doesn't mount this one, skip it.
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if(all) {
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if(strstr(m.mnt_opts,"noauto") || strstr(m.mnt_type,"swap"))
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continue;
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flags=0;
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/* If we're mounting something specific and this isn't it, skip it.
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* Note we must match both the exact text in fstab (ala "proc") or
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* a full path from root */
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} else if(strcmp(blockDevice,m.mnt_fsname) &&
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strcmp(argv[optind],m.mnt_fsname) &&
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strcmp(blockDevice,m.mnt_dir) &&
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strcmp(argv[optind],m.mnt_dir)) continue;
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/* Parse flags from /etc/fstab (unless this is a single mount
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* overriding fstab -- note the "all" test above zeroed the flags,
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* to prevent flags from previous entries affecting this one, so
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* the only way we could get here with nonzero flags is a single
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* mount). */
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if(!flags) {
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if(ENABLE_FEATURE_CLEAN_UP) free(string_flags);
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string_flags=NULL;
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parse_mount_options(m.mnt_opts, &flags, &string_flags);
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}
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/* Fill out remaining fields with info from mtab */
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if(ENABLE_FEATURE_CLEAN_UP) {
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free(blockDevice);
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blockDevice=strdup(m.mnt_fsname);
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free(directory);
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directory=strdup(m.mnt_type);
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} else {
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blockDevice=m.mnt_fsname;
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directory=m.mnt_dir;
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}
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fsType=m.mnt_type;
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/* Ok, we're ready to actually mount a specific source on a specific
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* directory now. */
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singlemount:
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// If they said -w, override fstab
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if(allowWrite) flags&=~MS_RDONLY;
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// Might this be an NFS filesystem?
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if(ENABLE_FEATURE_MOUNT_NFS && (!fsType || !strcmp(fsType,"nfs")) &&
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strchr(blockDevice, ':') != NULL)
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{
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if(nfsmount(blockDevice, directory, &flags, &string_flags, 1))
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bb_perror_msg("nfsmount failed");
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else {
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rc = 0;
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fsType="nfs";
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// Strangely enough, nfsmount() doesn't actually mount()
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goto mount_it_now;
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}
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} else {
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// Do we need to allocate a loopback device?
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if(ENABLE_FEATURE_MOUNT_LOOP && !fakeIt && S_ISREG(statbuf.st_mode))
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{
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loopFile = blockDevice;
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blockDevice = 0;
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switch(set_loop(&blockDevice, 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_and_die(
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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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break;
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}
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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(fsType || (flags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
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goto mount_it_now;
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}
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// Loop through filesystem types until mount succeeds or we run out
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for(i = 0; files[i] && rc; i++) {
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f = fopen(files[i], "r");
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if(!f) continue;
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// Get next block device backed filesystem
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for(buf = 0; (buf = fsType = bb_get_chomped_line_from_file(f));
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free(buf))
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{
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// Skip funky entries in /proc
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if(!strncmp(buf,"nodev",5) && isspace(buf[5])) continue;
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while(isspace(*fsType)) fsType++;
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if(*buf=='#' || *buf=='*') continue;
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if(!*fsType) continue;
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mount_it_now:
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// Okay, try to mount
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if (!fakeIt) {
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for(;;) {
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rc = mount(blockDevice, directory, fsType, flags, string_flags);
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if(!rc || (flags&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", blockDevice);
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flags|=MS_RDONLY;
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}
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}
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if(!rc || !f) break;
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}
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if(f) fclose(f);
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if(!f || !rc) break;
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}
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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 new entry to it now. */
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if((!rc || fakeIt) && useMtab) {
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FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
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if(!mountTable) bb_perror_msg(bb_path_mtab_file);
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else {
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// Remove trailing / (if any) from directory we mounted on
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int length=strlen(directory);
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if(length>1 && directory[length-1] == '/')
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directory[length-1]=0;
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// Fill out structure (should be ok to re-use existing one).
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m.mnt_fsname=blockDevice;
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m.mnt_dir=directory;
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m.mnt_type=fsType ? : "--bind";
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m.mnt_opts=string_flags ? :
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((flags & MS_RDONLY) ? "ro" : "rw");
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m.mnt_freq = 0;
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m.mnt_passno = 0;
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// Write and close
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addmntent(mountTable, &m);
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endmntent(mountTable);
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}
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} else {
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// Mount failed. Clean up
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if(loopFile) {
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del_loop(blockDevice);
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if(ENABLE_FEATURE_CLEAN_UP) free(loopFile);
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}
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// Don't whine about already mounted fs when mounting all.
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if(rc<0 && errno == EBUSY && all) rc = 0;
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else if (errno == EPERM)
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bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
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}
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// We couldn't free this earlier becase fsType could be in buf.
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if(ENABLE_FEATURE_CLEAN_UP) {
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free(buf);
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free(blockDevice);
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free(directory);
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}
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if(!all) break;
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}
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if(file) endmntent(file);
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if(rc) bb_perror_msg("Mounting %s on %s failed", blockDevice, directory);
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return rc;
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}
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