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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* 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
*/
#include <features.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include "libbb.h"
/* For 2.6, use the cleaned up header to get the 64 bit API. */
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
#include <linux/loop.h>
typedef struct loop_info64 bb_loop_info;
#define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
#define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
#else
/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
#include <linux/posix_types.h>
#define LO_NAME_SIZE 64
#define LO_KEY_SIZE 32
#define LOOP_SET_FD 0x4C00
#define LOOP_CLR_FD 0x4C01
#define BB_LOOP_SET_STATUS 0x4C02
#define BB_LOOP_GET_STATUS 0x4C03
typedef struct {
int lo_number;
__kernel_dev_t lo_device;
unsigned long lo_inode;
__kernel_dev_t lo_rdevice;
int lo_offset;
int lo_encrypt_type;
int lo_encrypt_key_size;
int lo_flags;
char lo_file_name[LO_NAME_SIZE];
unsigned char lo_encrypt_key[LO_KEY_SIZE];
unsigned long lo_init[2];
char reserved[4];
} bb_loop_info;
#endif
extern int del_loop(const char *device)
{
int fd,rc=0;
if ((fd = open(device, O_RDONLY)) < 0) rc=1;
else {
if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1;
close(fd);
}
return rc;
}
// Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
// *device is loop device to use, or if *device==NULL finds a loop device to
// mount it on and sets *device to a strdup of that loop device name. This
// search will re-use an existing loop device already bound to that
// file/offset if it finds one.
extern int set_loop(char **device, const char *file, int offset)
{
char dev[20];
bb_loop_info loopinfo;
struct stat statbuf;
int i, dfd, ffd, mode, rc=1;
// Open the file. Barf if this doesn't work.
if((ffd = open(file, mode=O_RDWR))<0)
if(errno!=EROFS || (ffd=open(file,mode=O_RDONLY))<0)
return errno;
// Find a loop device
for(i=0;rc;i++) {
sprintf(dev, LOOP_FORMAT, i++);
// Ran out of block devices, return failure.
if(stat(*device ? : dev, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
rc=ENOENT;
break;
}
// Open the sucker and check its loopiness.
if((dfd=open(dev, mode))<0 && errno==EROFS)
dfd=open(dev,mode=O_RDONLY);
if(dfd<0) continue;
rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
// If device free, claim it.
if(rc && errno==ENXIO) {
memset(&loopinfo, 0, sizeof(loopinfo));
safe_strncpy(loopinfo.lo_file_name, file, LO_NAME_SIZE);
loopinfo.lo_offset = offset;
// Associate free loop device with file
if(!ioctl(dfd, LOOP_SET_FD, ffd) &&
!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
else ioctl(dfd, LOOP_CLR_FD, 0);
// If this block device already set up right, re-use it.
// (Yes this is racy, but associating two loop devices with the same
// file isn't pretty either. In general, mounting the same file twice
// without using losetup manually is problematic.)
} else if(strcmp(file,loopinfo.lo_file_name)
|| offset!=loopinfo.lo_offset) rc=1;
close(dfd);
if(*device) break;
}
close(ffd);
if(!rc) {
if(!*device) *device=strdup(dev);
return mode==O_RDONLY ? 1 : 0;
} else return rc;
}
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/
|
