freebsd-dev/lib/libufs/type.c
Juli Mallett 990b6d05ab Allow libufs(3) functions to operate on a regular file. This makes it possible to
use almost anything that uses libufs(3) against a file as an unprivileged user, e.g.
tunefs(8) and dumpfs(8) against a makefs(8)-created image.

Prodded by:	kensmith
2009-06-11 18:04:57 +00:00

193 lines
4.9 KiB
C

/*
* Copyright (c) 2002 Juli Mallett. All rights reserved.
*
* This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
* FreeBSD project. Redistribution and use in source and binary forms, with
* or without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/disklabel.h>
#include <sys/stat.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <errno.h>
#include <fcntl.h>
#include <fstab.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libufs.h>
/* Internally, track the 'name' value, it's ours. */
#define MINE_NAME 0x01
/* Track if its fd points to a writable device. */
#define MINE_WRITE 0x02
int
ufs_disk_close(struct uufsd *disk)
{
ERROR(disk, NULL);
close(disk->d_fd);
if (disk->d_inoblock != NULL) {
free(disk->d_inoblock);
disk->d_inoblock = NULL;
}
if (disk->d_mine & MINE_NAME) {
free((char *)(uintptr_t)disk->d_name);
disk->d_name = NULL;
}
return (0);
}
int
ufs_disk_fillout(struct uufsd *disk, const char *name)
{
if (ufs_disk_fillout_blank(disk, name) == -1) {
return (-1);
}
if (sbread(disk) == -1) {
ERROR(disk, "could not read superblock to fill out disk");
return (-1);
}
return (0);
}
int
ufs_disk_fillout_blank(struct uufsd *disk, const char *name)
{
struct stat st;
struct fstab *fs;
struct statfs sfs;
const char *oname;
char dev[MAXPATHLEN];
int fd, ret;
ERROR(disk, NULL);
oname = name;
again: if ((ret = stat(name, &st)) < 0) {
if (*name != '/') {
snprintf(dev, sizeof(dev), "%s%s", _PATH_DEV, name);
name = dev;
goto again;
}
/*
* The given object doesn't exist, but don't panic just yet -
* it may be still mount point listed in /etc/fstab, but without
* existing corresponding directory.
*/
name = oname;
}
if (ret >= 0 && S_ISREG(st.st_mode)) {
/* Possibly a disk image, give it a try. */
;
} else if (ret >= 0 && S_ISCHR(st.st_mode)) {
/* This is what we need, do nothing. */
;
} else if ((fs = getfsfile(name)) != NULL) {
/*
* The given mount point is listed in /etc/fstab.
* It is possible that someone unmounted file system by hand
* and different file system is mounted on this mount point,
* but we still prefer /etc/fstab entry, because on the other
* hand, there could be /etc/fstab entry for this mount
* point, but file system is not mounted yet (eg. noauto) and
* statfs(2) will point us at different file system.
*/
name = fs->fs_spec;
} else if (ret >= 0 && S_ISDIR(st.st_mode)) {
/*
* The mount point is not listed in /etc/fstab, so it may be
* file system mounted by hand.
*/
if (statfs(name, &sfs) < 0) {
ERROR(disk, "could not find special device");
return (-1);
}
strlcpy(dev, sfs.f_mntfromname, sizeof(dev));
name = dev;
} else {
ERROR(disk, "could not find special device");
return (-1);
}
fd = open(name, O_RDONLY);
if (fd == -1) {
ERROR(disk, "could not open special device");
return (-1);
}
disk->d_bsize = 1;
disk->d_ccg = 0;
disk->d_fd = fd;
disk->d_inoblock = NULL;
disk->d_inomin = 0;
disk->d_inomax = 0;
disk->d_lcg = 0;
disk->d_mine = 0;
disk->d_ufs = 0;
disk->d_error = NULL;
if (oname != name) {
name = strdup(name);
if (name == NULL) {
ERROR(disk, "could not allocate memory for disk name");
return (-1);
}
disk->d_mine |= MINE_NAME;
}
disk->d_name = name;
return (0);
}
int
ufs_disk_write(struct uufsd *disk)
{
ERROR(disk, NULL);
if (disk->d_mine & MINE_WRITE)
return (0);
close(disk->d_fd);
disk->d_fd = open(disk->d_name, O_RDWR);
if (disk->d_fd < 0) {
ERROR(disk, "failed to open disk for writing");
return (-1);
}
disk->d_mine |= MINE_WRITE;
return (0);
}