[821] | 1 | /* vi: set sw=4 ts=4: */
|
---|
| 2 | /*
|
---|
| 3 | * Utility routines.
|
---|
| 4 | *
|
---|
| 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
|
---|
| 6 | *
|
---|
| 7 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
|
---|
| 8 | */
|
---|
| 9 |
|
---|
| 10 |
|
---|
| 11 | #include <features.h>
|
---|
| 12 | #include <stdio.h>
|
---|
| 13 | #include <errno.h>
|
---|
| 14 | #include <fcntl.h>
|
---|
| 15 | #include <string.h>
|
---|
| 16 | #include <unistd.h>
|
---|
| 17 | #include <sys/ioctl.h>
|
---|
| 18 | #include "libbb.h"
|
---|
| 19 |
|
---|
| 20 | /* For 2.6, use the cleaned up header to get the 64 bit API. */
|
---|
| 21 | #include <linux/version.h>
|
---|
| 22 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
|
---|
| 23 | #include <linux/loop.h>
|
---|
| 24 | typedef struct loop_info64 bb_loop_info;
|
---|
| 25 | #define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
|
---|
| 26 | #define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
|
---|
| 27 |
|
---|
| 28 | /* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
|
---|
| 29 | #else
|
---|
| 30 | /* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
|
---|
| 31 | #include <linux/posix_types.h>
|
---|
| 32 | #define LO_NAME_SIZE 64
|
---|
| 33 | #define LO_KEY_SIZE 32
|
---|
| 34 | #define LOOP_SET_FD 0x4C00
|
---|
| 35 | #define LOOP_CLR_FD 0x4C01
|
---|
| 36 | #define BB_LOOP_SET_STATUS 0x4C02
|
---|
| 37 | #define BB_LOOP_GET_STATUS 0x4C03
|
---|
| 38 | typedef struct {
|
---|
| 39 | int lo_number;
|
---|
| 40 | __kernel_dev_t lo_device;
|
---|
| 41 | unsigned long lo_inode;
|
---|
| 42 | __kernel_dev_t lo_rdevice;
|
---|
| 43 | int lo_offset;
|
---|
| 44 | int lo_encrypt_type;
|
---|
| 45 | int lo_encrypt_key_size;
|
---|
| 46 | int lo_flags;
|
---|
| 47 | char lo_file_name[LO_NAME_SIZE];
|
---|
| 48 | unsigned char lo_encrypt_key[LO_KEY_SIZE];
|
---|
| 49 | unsigned long lo_init[2];
|
---|
| 50 | char reserved[4];
|
---|
| 51 | } bb_loop_info;
|
---|
| 52 | #endif
|
---|
| 53 |
|
---|
| 54 | char *query_loop(const char *device)
|
---|
| 55 | {
|
---|
| 56 | int fd;
|
---|
| 57 | bb_loop_info loopinfo;
|
---|
| 58 | char *dev=0;
|
---|
| 59 |
|
---|
| 60 | if ((fd = open(device, O_RDONLY)) < 0) return 0;
|
---|
| 61 | if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo))
|
---|
| 62 | dev=bb_xasprintf("%ld %s", (long) loopinfo.lo_offset,
|
---|
| 63 | (char *)loopinfo.lo_file_name);
|
---|
| 64 | close(fd);
|
---|
| 65 |
|
---|
| 66 | return dev;
|
---|
| 67 | }
|
---|
| 68 |
|
---|
| 69 |
|
---|
| 70 | int del_loop(const char *device)
|
---|
| 71 | {
|
---|
| 72 | int fd, rc;
|
---|
| 73 |
|
---|
| 74 | if ((fd = open(device, O_RDONLY)) < 0) return 1;
|
---|
| 75 | rc=ioctl(fd, LOOP_CLR_FD, 0);
|
---|
| 76 | close(fd);
|
---|
| 77 |
|
---|
| 78 | return rc;
|
---|
| 79 | }
|
---|
| 80 |
|
---|
| 81 | /* Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
|
---|
| 82 | *device is loop device to use, or if *device==NULL finds a loop device to
|
---|
| 83 | mount it on and sets *device to a strdup of that loop device name. This
|
---|
| 84 | search will re-use an existing loop device already bound to that
|
---|
| 85 | file/offset if it finds one.
|
---|
| 86 | */
|
---|
| 87 | int set_loop(char **device, const char *file, int offset)
|
---|
| 88 | {
|
---|
| 89 | char dev[20], *try;
|
---|
| 90 | bb_loop_info loopinfo;
|
---|
| 91 | struct stat statbuf;
|
---|
| 92 | int i, dfd, ffd, mode, rc=-1;
|
---|
| 93 |
|
---|
| 94 | /* Open the file. Barf if this doesn't work. */
|
---|
| 95 | if((ffd = open(file, mode=O_RDWR))<0 && (ffd = open(file,mode=O_RDONLY))<0)
|
---|
| 96 | return -errno;
|
---|
| 97 |
|
---|
| 98 | /* Find a loop device. */
|
---|
| 99 | try=*device ? : dev;
|
---|
| 100 | for(i=0;rc;i++) {
|
---|
| 101 | sprintf(dev, LOOP_FORMAT, i);
|
---|
| 102 |
|
---|
| 103 | /* Ran out of block devices, return failure. */
|
---|
| 104 | if(stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
|
---|
| 105 | rc=-ENOENT;
|
---|
| 106 | break;
|
---|
| 107 | }
|
---|
| 108 | /* Open the sucker and check its loopiness. */
|
---|
| 109 | if((dfd=open(try, mode))<0 && errno==EROFS)
|
---|
| 110 | dfd=open(try, mode = O_RDONLY);
|
---|
| 111 | if(dfd<0) goto try_again;
|
---|
| 112 |
|
---|
| 113 | rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
|
---|
| 114 |
|
---|
| 115 | /* If device free, claim it. */
|
---|
| 116 | if(rc && errno==ENXIO) {
|
---|
| 117 | memset(&loopinfo, 0, sizeof(loopinfo));
|
---|
| 118 | safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
|
---|
| 119 | loopinfo.lo_offset = offset;
|
---|
| 120 | /* Associate free loop device with file. */
|
---|
| 121 | if(!ioctl(dfd, LOOP_SET_FD, ffd)) {
|
---|
| 122 | if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
|
---|
| 123 | else ioctl(dfd, LOOP_CLR_FD, 0);
|
---|
| 124 | }
|
---|
| 125 |
|
---|
| 126 | /* If this block device already set up right, re-use it.
|
---|
| 127 | (Yes this is racy, but associating two loop devices with the same
|
---|
| 128 | file isn't pretty either. In general, mounting the same file twice
|
---|
| 129 | without using losetup manually is problematic.)
|
---|
| 130 | */
|
---|
| 131 | } else if(strcmp(file,(char *)loopinfo.lo_file_name)
|
---|
| 132 | || offset!=loopinfo.lo_offset) rc=-1;
|
---|
| 133 | close(dfd);
|
---|
| 134 | try_again:
|
---|
| 135 | if(*device) break;
|
---|
| 136 | }
|
---|
| 137 | close(ffd);
|
---|
| 138 | if(!rc) {
|
---|
| 139 | if(!*device) *device=strdup(dev);
|
---|
| 140 | return mode==O_RDONLY ? 1 : 0;
|
---|
| 141 | } else return rc;
|
---|
| 142 | }
|
---|