1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
29 #include <sys/ioctl.h>
32 /* For 2.6, use the cleaned up header to get the 64 bit API. */
33 #include <linux/version.h>
34 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
35 #include <linux/loop.h>
36 typedef struct loop_info64 bb_loop_info;
37 #define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
38 #define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
40 /* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
42 /* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
43 #include <linux/posix_types.h>
44 #define LO_NAME_SIZE 64
45 #define LO_KEY_SIZE 32
46 #define LOOP_SET_FD 0x4C00
47 #define LOOP_CLR_FD 0x4C01
48 #define BB_LOOP_SET_STATUS 0x4C02
49 #define BB_LOOP_GET_STATUS 0x4C03
52 __kernel_dev_t lo_device;
53 unsigned long lo_inode;
54 __kernel_dev_t lo_rdevice;
57 int lo_encrypt_key_size;
59 char lo_file_name[LO_NAME_SIZE];
60 unsigned char lo_encrypt_key[LO_KEY_SIZE];
61 unsigned long lo_init[2];
66 extern int del_loop(const char *device)
70 if ((fd = open(device, O_RDONLY)) < 0) rc=1;
72 if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1;
78 // Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
79 // *device is loop device to use, or if *device==NULL finds a loop device to
80 // mount it on and sets *device to a strdup of that loop device name. This
81 // search will re-use an existing loop device already bound to that
82 // file/offset if it finds one.
83 extern int set_loop(char **device, const char *file, int offset)
86 bb_loop_info loopinfo;
88 int i, dfd, ffd, mode, rc=1;
90 // Open the file. Barf if this doesn't work.
91 if((ffd = open(file, mode=O_RDWR))<0 && (ffd = open(file,mode=O_RDONLY))<0)
96 sprintf(dev, LOOP_FORMAT, i++);
97 // Ran out of block devices, return failure.
98 if(stat(*device ? : dev, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
102 // Open the sucker and check its loopiness.
103 if((dfd=open(dev, mode))<0 && errno==EROFS)
104 dfd=open(dev,mode=O_RDONLY);
107 rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
108 // If device free, claim it.
109 if(rc && errno==ENXIO) {
110 memset(&loopinfo, 0, sizeof(loopinfo));
111 safe_strncpy(loopinfo.lo_file_name, file, LO_NAME_SIZE);
112 loopinfo.lo_offset = offset;
113 // Associate free loop device with file
114 if(!ioctl(dfd, LOOP_SET_FD, ffd) &&
115 !ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
116 else ioctl(dfd, LOOP_CLR_FD, 0);
117 // If this block device already set up right, re-use it.
118 // (Yes this is racy, but associating two loop devices with the same
119 // file isn't pretty either. In general, mounting the same file twice
120 // without using losetup manually is problematic.)
121 } else if(strcmp(file,loopinfo.lo_file_name)
122 || offset!=loopinfo.lo_offset) rc=1;
128 if(!*device) *device=strdup(dev);
129 return mode==O_RDONLY ? 1 : 0;
136 c-file-style: "linux"