busybox/mount.c
2000-01-15 22:28:50 +00:00

472 lines
12 KiB
C

/*
* Mini mount implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* 3/21/1999 Charles P. Wright <cpwright@cpwright.com>
* searches through fstab when -a is passed
* will try mounting stuff with all fses when passed -t auto
*
* 1999-04-17 Dave Cinege...Rewrote -t auto. Fixed ro mtab.
*
* 1999-10-07 Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
* Rewrite of a lot of code. Removed mtab usage (I plan on
* putting it back as a compile-time option some time),
* major adjustments to option parsing, and some serious
* dieting all around.
*
* 1999-11-06 mtab suppport is back - andersee
*
* 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's
* mount to add loop support.
*/
#include "internal.h"
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <mntent.h>
#include <sys/mount.h>
#include <ctype.h>
#include <fstab.h>
#if defined BB_FEATURE_MOUNT_LOOP
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/loop.h>
static int set_loop(const char *device, const char *file, int offset, int *loopro);
static char *find_unused_loop_device (void);
static int use_loop = 0;
#endif
extern const char mtab_file[]; /* Defined in utility.c */
static const char mount_usage[] = "\tmount [flags]\n"
"\tmount [flags] device directory [-o options,more-options]\n"
"\n"
"Flags:\n"
"\t-a:\tMount all file systems in fstab.\n"
#ifdef BB_MTAB
"\t-f:\t\"Fake\" mount. Add entry to mount table but don't mount it.\n"
"\t-n:\tDon't write a mount table entry.\n"
#endif
"\t-o option:\tOne of many filesystem options, listed below.\n"
"\t-r:\tMount the filesystem read-only.\n"
"\t-t filesystem-type:\tSpecify the filesystem type.\n"
"\t-w:\tMount for reading and writing (default).\n"
"\n"
"Options for use with the \"-o\" flag:\n"
"\tasync / sync:\tWrites are asynchronous / synchronous.\n"
"\tdev / nodev:\tAllow use of special device files / disallow them.\n"
"\texec / noexec:\tAllow use of executable files / disallow them.\n"
#if defined BB_FEATURE_MOUNT_LOOP
"\tloop: Mounts a file via loop device.\n"
#endif
"\tsuid / nosuid:\tAllow set-user-id-root programs / disallow them.\n"
"\tremount: Re-mount a currently-mounted filesystem, changing its flags.\n"
"\tro / rw: Mount for read-only / read-write.\n"
"\t"
"There are EVEN MORE flags that are specific to each filesystem.\n"
"You'll have to see the written documentation for those.\n";
struct mount_options {
const char *name;
unsigned long and;
unsigned long or;
};
static const struct mount_options mount_options[] = {
{"async", ~MS_SYNCHRONOUS, 0},
{"defaults", ~0, 0},
{"dev", ~MS_NODEV, 0},
{"exec", ~MS_NOEXEC, 0},
{"nodev", ~0, MS_NODEV},
{"noexec", ~0, MS_NOEXEC},
{"nosuid", ~0, MS_NOSUID},
{"remount", ~0, MS_REMOUNT},
{"ro", ~0, MS_RDONLY},
{"rw", ~MS_RDONLY, 0},
{"suid", ~MS_NOSUID, 0},
{"sync", ~0, MS_SYNCHRONOUS},
{0, 0, 0}
};
static int
do_mount(char* specialfile, char* dir, char* filesystemtype,
long flags, void* string_flags, int useMtab, int fakeIt, char* mtab_opts)
{
int status=0;
#if defined BB_MTAB
if (fakeIt==FALSE)
#endif
{
#if defined BB_FEATURE_MOUNT_LOOP
if (use_loop) {
int loro = flags & MS_RDONLY;
char *lofile = specialfile;
specialfile = find_unused_loop_device();
if (specialfile == NULL) {
fprintf(stderr, "Could not find a spare loop device\n");
exit(1);
}
if (set_loop (specialfile, lofile, 0, &loro)) {
fprintf(stderr, "Could not setup loop device\n");
exit(1);
}
if (!(flags & MS_RDONLY) && loro) { /* loop is ro, but wanted rw */
fprintf(stderr, "WARNING: loop device is read-only\n");
flags &= ~MS_RDONLY;
}
}
#endif
status=mount(specialfile, dir, filesystemtype, flags, string_flags);
}
#if defined BB_MTAB
if (status == 0) {
if (useMtab==TRUE)
write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
return 0;
}
else
#endif
return(status);
}
#if defined BB_MTAB
#define whine_if_fstab_is_missing() {}
#else
extern void whine_if_fstab_is_missing()
{
struct stat statBuf;
if (stat("/etc/fstab", &statBuf) < 0)
fprintf(stderr, "/etc/fstab file missing -- install one to name /dev/root.\n\n");
}
#endif
/* Seperate standard mount options from the nonstandard string options */
static void
parse_mount_options ( char *options, unsigned long *flags, char *strflags)
{
while (options) {
int gotone=FALSE;
char *comma = strchr (options, ',');
const struct mount_options* f = mount_options;
if (comma)
*comma = '\0';
while (f->name != 0) {
if (strcasecmp (f->name, options) == 0) {
*flags &= f->and;
*flags |= f->or;
gotone=TRUE;
break;
}
f++;
}
#if defined BB_FEATURE_MOUNT_LOOP
if (gotone==FALSE && !strcasecmp ("loop", options)) { /* loop device support */
use_loop = 1;
gotone=TRUE;
}
#endif
if (*strflags && strflags!= '\0' && gotone==FALSE) {
char *temp=strflags;
temp += strlen (strflags);
*temp++ = ',';
*temp++ = '\0';
}
if (gotone==FALSE)
strcat (strflags, options);
if (comma) {
*comma = ',';
options = ++comma;
} else {
break;
}
}
}
int
mount_one(char *blockDevice, char *directory, char *filesystemType,
unsigned long flags, char *string_flags, int useMtab, int fakeIt, char *mtab_opts)
{
int status = 0;
char buf[255];
#if defined BB_FEATURE_USE_PROCFS
if (strcmp(filesystemType, "auto") == 0) {
FILE *f = fopen ("/proc/filesystems", "r");
if (f == NULL)
return( FALSE);
while (fgets (buf, sizeof (buf), f) != NULL) {
filesystemType = buf;
if (*filesystemType == '\t') { // Not a nodev filesystem
// Add NULL termination to each line
while (*filesystemType && *filesystemType != '\n')
filesystemType++;
*filesystemType = '\0';
filesystemType = buf;
filesystemType++; // hop past tab
status = do_mount (blockDevice, directory, filesystemType,
flags | MS_MGC_VAL, string_flags, useMtab,
fakeIt, mtab_opts);
if (status == 0)
break;
}
}
fclose (f);
} else
#endif
{
status = do_mount (blockDevice, directory, filesystemType,
flags | MS_MGC_VAL, string_flags, useMtab,
fakeIt, mtab_opts);
}
if (status) {
fprintf (stderr, "Mounting %s on %s failed: %s\n",
blockDevice, directory, strerror(errno));
return (FALSE);
}
return (TRUE);
}
extern int mount_main (int argc, char **argv)
{
char string_flags_buf[1024]="";
char *string_flags = string_flags_buf;
char *extra_opts = string_flags_buf;
unsigned long flags = 0;
char *filesystemType = "auto";
char *device = NULL;
char *directory = NULL;
int all = FALSE;
int fakeIt = FALSE;
int useMtab = TRUE;
int i;
/* Only compiled in if BB_MTAB is not defined */
whine_if_fstab_is_missing();
if (argc == 1) {
FILE *mountTable = setmntent (mtab_file, "r");
if (mountTable) {
struct mntent *m;
while ((m = getmntent (mountTable)) != 0) {
struct fstab* fstabItem;
char *blockDevice = m->mnt_fsname;
/* Note that if /etc/fstab is missing, libc can't fix up /dev/root for us */
if (strcmp (blockDevice, "/dev/root") == 0) {
fstabItem = getfsfile ("/");
if (fstabItem != NULL)
blockDevice = fstabItem->fs_spec;
}
printf ("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,
m->mnt_type, m->mnt_opts);
}
endmntent (mountTable);
} else {
perror(mtab_file);
}
exit( TRUE);
}
/* Parse options */
i = --argc;
argv++;
while (i > 0 && **argv) {
if (**argv == '-') {
char *opt = *argv;
while (i>0 && *++opt) switch (*opt) {
case 'o':
if (--i == 0) {
goto goodbye;
}
parse_mount_options (*(++argv), &flags, string_flags);
break;
case 'r':
flags |= MS_RDONLY;
break;
case 't':
if (--i == 0) {
goto goodbye;
}
filesystemType = *(++argv);
break;
case 'w':
flags &= ~MS_RDONLY;
break;
case 'a':
all = TRUE;
break;
#ifdef BB_MTAB
case 'f':
fakeIt = TRUE;
break;
case 'n':
useMtab = FALSE;
break;
#endif
case 'v':
case 'h':
case '-':
goto goodbye;
}
} else {
if (device == NULL)
device=*argv;
else if (directory == NULL)
directory=*argv;
else {
goto goodbye;
}
}
i--;
argv++;
}
if (all == TRUE) {
struct mntent *m;
FILE *f = setmntent ("/etc/fstab", "r");
if (f == NULL) {
perror("/etc/fstab");
exit( FALSE);
}
while ((m = getmntent (f)) != NULL) {
// If the file system isn't noauto, and isn't mounted on /,
// and isn't swap or nfs, then mount it
if ((!strstr (m->mnt_opts, "noauto")) &&
(m->mnt_dir[1] != '\0') &&
(!strstr (m->mnt_type, "swap")) &&
(!strstr (m->mnt_type, "nfs")))
{
flags = 0;
*string_flags = '\0';
parse_mount_options(m->mnt_opts, &flags, string_flags);
mount_one (m->mnt_fsname, m->mnt_dir, m->mnt_type,
flags, string_flags, useMtab, fakeIt, extra_opts);
}
}
endmntent (f);
} else {
if (device && directory) {
#ifdef BB_NFSMOUNT
if (strcmp(filesystemType, "nfs") == 0) {
if (nfsmount(device, directory, &flags, &extra_opts, &string_flags, 1) != 0)
exit(FALSE);
}
#endif
exit (mount_one (device, directory, filesystemType,
flags, string_flags, useMtab, fakeIt, extra_opts));
} else {
goto goodbye;
}
}
exit( TRUE);
goodbye:
usage( mount_usage);
}
#if defined BB_FEATURE_MOUNT_LOOP
static int set_loop(const char *device, const char *file, int offset, int *loopro)
{
struct loop_info loopinfo;
int fd, ffd, mode;
mode = *loopro ? O_RDONLY : O_RDWR;
if ((ffd = open (file, mode)) < 0 && !*loopro
&& (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
perror (file);
return 1;
}
if ((fd = open (device, mode)) < 0) {
close(ffd);
perror (device);
return 1;
}
*loopro = (mode == O_RDONLY);
memset(&loopinfo, 0, sizeof(loopinfo));
strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
loopinfo.lo_offset = offset;
loopinfo.lo_encrypt_key_size = 0;
if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
perror("ioctl: LOOP_SET_FD");
exit(1);
}
if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
(void) ioctl(fd, LOOP_CLR_FD, 0);
perror("ioctl: LOOP_SET_STATUS");
exit(1);
}
close(fd);
close(ffd);
return 0;
}
static char *find_unused_loop_device (void)
{
char dev[20];
int i, fd, somedev = 0, someloop = 0;
struct stat statbuf;
struct loop_info loopinfo;
for(i = 0; i < 256; i++) {
sprintf(dev, "/dev/loop%d", i);
if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
somedev++;
fd = open (dev, O_RDONLY);
if (fd >= 0) {
if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == 0)
someloop++; /* in use */
else if (errno == ENXIO) {
close (fd);
return strdup(dev); /* probably free */
}
close (fd);
}
continue;
}
if (i >= 7)
break;
}
return NULL;
}
#endif /* BB_FEATURE_MOUNT_LOOP */