hush/util-linux/mount.c
Rob Landley 71d6ccd801 With -a, the jump to mount_it_now can skip the initialization of f, and
if we don't zero it after closing it we re-close a filehandle that isn't
open, and since this is a file _pointer_ it segfaults on a double free.

Yeah, subtle bug.  I need to break this out into separate functions if I can
figure out how to avoid making the code larger while doing so.  Part of
the general -a and -o remount work I need to do, but that's after 1.1.0...
2006-01-10 05:30:28 +00:00

387 lines
10 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini mount implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <mntent.h>
#include <ctype.h>
#include <sys/mount.h>
#include <fcntl.h> // for CONFIG_FEATURE_MOUNT_LOOP
#include <sys/ioctl.h> // for CONFIG_FEATURE_MOUNT_LOOP
#include "busybox.h"
// These two aren't always defined in old headers
#ifndef MS_BIND
#define MS_BIND 4096
#endif
#ifndef MS_MOVE
#define MS_MOVE 8192
#endif
/* Consume standard mount options (from -o options or --options).
* Set appropriate flags and collect unrecognized ones as a comma separated
* string to pass to kernel */
struct {
const char *name;
long flags;
} static const mount_options[] = {
{"loop", 0},
{"defaults", 0},
{"noauto", 0},
{"ro", MS_RDONLY},
{"rw", ~MS_RDONLY},
{"nosuid", MS_NOSUID},
{"suid", ~MS_NOSUID},
{"dev", ~MS_NODEV},
{"nodev", MS_NODEV},
{"exec", ~MS_NOEXEC},
{"noexec", MS_NOEXEC},
{"sync", MS_SYNCHRONOUS},
{"async", ~MS_SYNCHRONOUS},
{"remount", MS_REMOUNT},
{"atime", ~MS_NOATIME},
{"noatime", MS_NOATIME},
{"diratime", ~MS_NODIRATIME},
{"nodiratime", MS_NODIRATIME},
{"bind", MS_BIND},
{"move", MS_MOVE}
};
/* Uses the mount_options list above */
static void parse_mount_options(char *options, int *flags, char **strflags)
{
// Loop through options
for(;;) {
int i;
char *comma = strchr(options, ',');
if(comma) *comma = 0;
// Find this option in mount_options
for(i = 0; i < (sizeof(mount_options) / sizeof(*mount_options)); i++) {
if(!strcasecmp(mount_options[i].name, options)) {
long fl = mount_options[i].flags;
if(fl < 0) *flags &= fl;
else *flags |= fl;
break;
}
}
// Unrecognized mount option?
if(i == (sizeof(mount_options) / sizeof(*mount_options))) {
// Add it to strflags, to pass on to kernel
i = *strflags ? strlen(*strflags) : 0;
*strflags = xrealloc(*strflags, i+strlen(options)+2);
// Comma separated if it's not the first one
if(i) (*strflags)[i++] = ',';
strcpy((*strflags)+i, options);
}
// Advance to next option, or finish
if(comma) {
*comma = ',';
options = ++comma;
} else break;
}
}
/* This does the work */
extern int mount_main(int argc, char **argv)
{
char *string_flags = 0, *fsType = 0, *blockDevice = 0, *directory = 0,
*loopFile = 0, *buf = 0,
*files[] = {"/etc/filesystems", "/proc/filesystems", 0};
int i, opt, all = FALSE, fakeIt = FALSE, allowWrite = FALSE,
rc = 1, useMtab = ENABLE_FEATURE_MTAB_SUPPORT;
int flags=0xc0ed0000; // Needed for linux 2.2, ignored by 2.4 and 2.6.
FILE *file = 0,*f = 0;
char path[PATH_MAX*2];
struct mntent m;
struct stat statbuf;
/* parse long options, like --bind and --move. Note that -o option
* and --option are synonymous. Yes, this means --remount,rw works. */
for(i = opt = 0; i < argc; i++) {
if(argv[i][0] == '-' && argv[i][1] == '-')
parse_mount_options(argv[i]+2, &flags, &string_flags);
else argv[opt++] = argv[i];
}
argc = opt;
// Parse remaining options
while((opt = getopt(argc, argv, "o:t:rwafnv")) > 0) {
switch (opt) {
case 'o':
parse_mount_options(optarg, &flags, &string_flags);
break;
case 't':
fsType = optarg;
break;
case 'r':
flags |= MS_RDONLY;
break;
case 'w':
allowWrite=TRUE;
break;
case 'a':
all = TRUE;
break;
case 'f':
fakeIt = TRUE;
break;
case 'n':
useMtab = FALSE;
break;
case 'v':
break; // ignore -v
default:
bb_show_usage();
}
}
// If we have no arguments, show currently mounted filesystems
if(!all && (optind == argc)) {
FILE *mountTable = setmntent(bb_path_mtab_file, "r");
if(!mountTable) bb_perror_msg_and_die(bb_path_mtab_file);
while (getmntent_r(mountTable,&m,path,sizeof(path))) {
blockDevice = m.mnt_fsname;
// Clean up display a little bit regarding root device
if(!strcmp(blockDevice, "rootfs")) continue;
if(!strcmp(blockDevice, "/dev/root"))
blockDevice = find_block_device("/");
if(!fsType || !strcmp(m.mnt_type, fsType))
printf("%s on %s type %s (%s)\n", blockDevice, m.mnt_dir,
m.mnt_type, m.mnt_opts);
if(ENABLE_FEATURE_CLEAN_UP && blockDevice != m.mnt_fsname)
free(blockDevice);
}
endmntent(mountTable);
return EXIT_SUCCESS;
}
/* The next argument is what to mount. if there's an argument after that
* it's where to mount it. If we're not mounting all, and we have both
* of these arguments, jump straight to the actual mount. */
statbuf.st_mode=0;
if(optind < argc)
blockDevice = !stat(argv[optind], &statbuf) ?
bb_simplify_path(argv[optind]) :
(ENABLE_FEATURE_CLEAN_UP ? strdup(argv[optind]) : argv[optind]);
if(optind+1 < argc) directory = bb_simplify_path(argv[optind+1]);
// If we don't have to loop through fstab, skip ahead a bit.
if(!all && optind+1!=argc) goto singlemount;
// Loop through /etc/fstab entries to look up this entry.
if(!(file=setmntent("/etc/fstab","r")))
bb_perror_msg_and_die("\nCannot read /etc/fstab");
for(;;) {
// Get next fstab entry
if(!getmntent_r(file,&m,path,sizeof(path))) {
if(!all)
bb_perror_msg("Can't find %s in /etc/fstab\n", blockDevice);
break;
}
// If we're mounting all and all doesn't mount this one, skip it.
if(all) {
if(strstr(m.mnt_opts,"noauto") || strstr(m.mnt_type,"swap"))
continue;
flags=0;
/* If we're mounting something specific and this isn't it, skip it.
* Note we must match both the exact text in fstab (ala "proc") or
* a full path from root */
} else if(strcmp(blockDevice,m.mnt_fsname) &&
strcmp(argv[optind],m.mnt_fsname) &&
strcmp(blockDevice,m.mnt_dir) &&
strcmp(argv[optind],m.mnt_dir)) continue;
/* Parse flags from /etc/fstab (unless this is a single mount
* overriding fstab -- note the "all" test above zeroed the flags,
* to prevent flags from previous entries affecting this one, so
* the only way we could get here with nonzero flags is a single
* mount). */
if(!flags) {
if(ENABLE_FEATURE_CLEAN_UP) free(string_flags);
string_flags=NULL;
parse_mount_options(m.mnt_opts, &flags, &string_flags);
}
/* Fill out remaining fields with info from mtab */
if(ENABLE_FEATURE_CLEAN_UP) {
free(blockDevice);
blockDevice=strdup(m.mnt_fsname);
free(directory);
directory=strdup(m.mnt_dir);
} else {
blockDevice=m.mnt_fsname;
directory=m.mnt_dir;
}
fsType=m.mnt_type;
/* Ok, we're ready to actually mount a specific source on a specific
* directory now. */
singlemount:
// If they said -w, override fstab
if(allowWrite) flags&=~MS_RDONLY;
// Might this be an NFS filesystem?
if(ENABLE_FEATURE_MOUNT_NFS && (!fsType || !strcmp(fsType,"nfs")) &&
strchr(blockDevice, ':') != NULL)
{
if(nfsmount(blockDevice, directory, &flags, &string_flags, 1))
bb_perror_msg("nfsmount failed");
else {
rc = 0;
fsType="nfs";
// Strangely enough, nfsmount() doesn't actually mount()
goto mount_it_now;
}
} else {
// Do we need to allocate a loopback device?
if(ENABLE_FEATURE_MOUNT_LOOP && !fakeIt && S_ISREG(statbuf.st_mode))
{
loopFile = blockDevice;
blockDevice = 0;
switch(set_loop(&blockDevice, loopFile, 0)) {
case 0:
case 1:
break;
default:
bb_error_msg_and_die(
errno == EPERM || errno == EACCES ?
bb_msg_perm_denied_are_you_root :
"Couldn't setup loop device");
break;
}
}
/* If we know the fstype (or don't need to), jump straight
* to the actual mount. */
if(fsType || (flags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
goto mount_it_now;
}
// Loop through filesystem types until mount succeeds or we run out
for(i = 0; files[i] && rc; i++) {
f = fopen(files[i], "r");
if(!f) continue;
// Get next block device backed filesystem
for(buf = 0; (buf = fsType = bb_get_chomped_line_from_file(f));
free(buf))
{
// Skip funky entries in /proc
if(!strncmp(buf,"nodev",5) && isspace(buf[5])) continue;
while(isspace(*fsType)) fsType++;
if(*buf=='#' || *buf=='*') continue;
if(!*fsType) continue;
mount_it_now:
// Okay, try to mount
if (!fakeIt) {
for(;;) {
rc = mount(blockDevice, directory, fsType, flags, string_flags);
if(!rc || (flags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
break;
bb_error_msg("%s is write-protected, mounting read-only", blockDevice);
flags|=MS_RDONLY;
}
}
if(!rc || !f) break;
}
if(!f) break;
fclose(f);
// goto mount_it_now with -a can jump past the initialization
f=0;
if(!rc) break;
}
/* If the mount was successful, and we're maintaining an old-style
* mtab file by hand, add new entry to it now. */
if((!rc || fakeIt) && useMtab) {
FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
if(!mountTable) bb_perror_msg(bb_path_mtab_file);
else {
// Remove trailing / (if any) from directory we mounted on
int length=strlen(directory);
if(length>1 && directory[length-1] == '/')
directory[length-1]=0;
// Fill out structure (should be ok to re-use existing one).
m.mnt_fsname=blockDevice;
m.mnt_dir=directory;
m.mnt_type=fsType ? : "--bind";
m.mnt_opts=string_flags ? :
((flags & MS_RDONLY) ? "ro" : "rw");
m.mnt_freq = 0;
m.mnt_passno = 0;
// Write and close
addmntent(mountTable, &m);
endmntent(mountTable);
}
} else {
// Mount failed. Clean up
if(loopFile) {
del_loop(blockDevice);
if(ENABLE_FEATURE_CLEAN_UP) free(loopFile);
}
// Don't whine about already mounted fs when mounting all.
if(rc<0 && errno == EBUSY && all) rc = 0;
else if (errno == EPERM)
bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
}
// We couldn't free this earlier becase fsType could be in buf.
if(ENABLE_FEATURE_CLEAN_UP) free(buf);
if(!all) break;
}
if(file) endmntent(file);
if(rc) bb_perror_msg("Mounting %s on %s failed", blockDevice, directory);
if(ENABLE_FEATURE_CLEAN_UP) {
free(blockDevice);
free(directory);
}
return rc;
}