Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * Utility routines. |
| 4 | * |
Bernhard Reutner-Fischer | 7547a6e | 2005-10-15 20:56:31 +0000 | [diff] [blame] | 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
Rob Landley | 5343747 | 2006-07-16 08:14:35 +0000 | [diff] [blame] | 6 | * Copyright (C) 2005 by Rob Landley <rob@landley.net> |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 7 | * |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 8 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 9 | */ |
| 10 | |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 11 | #include "libbb.h" |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 12 | |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 13 | /* For 2.6, use the cleaned up header to get the 64 bit API. */ |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 14 | #include <linux/version.h> |
Eric Andersen | cf6ef05 | 2004-08-16 08:29:44 +0000 | [diff] [blame] | 15 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 16 | #include <linux/loop.h> |
| 17 | typedef struct loop_info64 bb_loop_info; |
| 18 | #define BB_LOOP_SET_STATUS LOOP_SET_STATUS64 |
| 19 | #define BB_LOOP_GET_STATUS LOOP_GET_STATUS64 |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 20 | |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 21 | /* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */ |
| 22 | #else |
| 23 | /* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/ |
| 24 | #include <linux/posix_types.h> |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 25 | #define LO_NAME_SIZE 64 |
| 26 | #define LO_KEY_SIZE 32 |
| 27 | #define LOOP_SET_FD 0x4C00 |
| 28 | #define LOOP_CLR_FD 0x4C01 |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 29 | #define BB_LOOP_SET_STATUS 0x4C02 |
| 30 | #define BB_LOOP_GET_STATUS 0x4C03 |
| 31 | typedef struct { |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 32 | int lo_number; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 33 | __kernel_dev_t lo_device; |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 34 | unsigned long lo_inode; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 35 | __kernel_dev_t lo_rdevice; |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 36 | int lo_offset; |
| 37 | int lo_encrypt_type; |
| 38 | int lo_encrypt_key_size; |
| 39 | int lo_flags; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 40 | char lo_file_name[LO_NAME_SIZE]; |
Eric Andersen | ef8cd3b | 2004-02-06 07:16:36 +0000 | [diff] [blame] | 41 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; |
| 42 | unsigned long lo_init[2]; |
| 43 | char reserved[4]; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 44 | } bb_loop_info; |
| 45 | #endif |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 46 | |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 47 | char *query_loop(const char *device) |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 48 | { |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 49 | int fd; |
| 50 | bb_loop_info loopinfo; |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 51 | char *dev = 0; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 52 | |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 53 | fd = open(device, O_RDONLY); |
| 54 | if (fd < 0) return 0; |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 55 | if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo)) |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 56 | dev = xasprintf("%ld %s", (long) loopinfo.lo_offset, |
Eric Andersen | 76b2427 | 2006-01-30 17:30:22 +0000 | [diff] [blame] | 57 | (char *)loopinfo.lo_file_name); |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 58 | close(fd); |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 59 | |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 60 | return dev; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 61 | } |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 62 | |
| 63 | |
| 64 | int del_loop(const char *device) |
| 65 | { |
| 66 | int fd, rc; |
| 67 | |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 68 | fd = open(device, O_RDONLY); |
| 69 | if (fd < 0) return 1; |
| 70 | rc = ioctl(fd, LOOP_CLR_FD, 0); |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 71 | close(fd); |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 72 | |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 73 | return rc; |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 74 | } |
| 75 | |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 76 | /* Returns 0 if mounted RW, 1 if mounted read-only, <0 for error. |
| 77 | *device is loop device to use, or if *device==NULL finds a loop device to |
| 78 | mount it on and sets *device to a strdup of that loop device name. This |
| 79 | search will re-use an existing loop device already bound to that |
| 80 | file/offset if it finds one. |
| 81 | */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 82 | int set_loop(char **device, const char *file, unsigned long long offset) |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 83 | { |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 84 | char dev[20], *try; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 85 | bb_loop_info loopinfo; |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 86 | struct stat statbuf; |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 87 | int i, dfd, ffd, mode, rc = -1; |
Denis Vlasenko | 9213a9e | 2006-09-17 16:28:10 +0000 | [diff] [blame] | 88 | |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 89 | /* Open the file. Barf if this doesn't work. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 90 | mode = O_RDWR; |
| 91 | ffd = open(file, mode); |
| 92 | if (ffd < 0) { |
| 93 | mode = O_RDONLY; |
| 94 | ffd = open(file, mode); |
| 95 | if (ffd < 0) |
| 96 | return -errno; |
| 97 | } |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 98 | |
| 99 | /* Find a loop device. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 100 | try = *device ? : dev; |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 101 | for (i = 0; rc; i++) { |
Rob Landley | b70ccd9 | 2006-01-22 23:17:18 +0000 | [diff] [blame] | 102 | sprintf(dev, LOOP_FORMAT, i); |
Rob Landley | aae8b34 | 2006-03-18 02:38:10 +0000 | [diff] [blame] | 103 | |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 104 | /* Ran out of block devices, return failure. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 105 | if (stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) { |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 106 | rc = -ENOENT; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 107 | break; |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 108 | } |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 109 | /* Open the sucker and check its loopiness. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 110 | dfd = open(try, mode); |
| 111 | if (dfd < 0 && errno == EROFS) { |
| 112 | mode = O_RDONLY; |
| 113 | dfd = open(try, mode); |
| 114 | } |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 115 | if (dfd < 0) |
| 116 | goto try_again; |
Eric Andersen | aad1a88 | 2001-03-16 22:47:14 +0000 | [diff] [blame] | 117 | |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 118 | rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo); |
Rob Landley | 1d589b2 | 2005-11-29 23:47:10 +0000 | [diff] [blame] | 119 | |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 120 | /* If device is free, claim it. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 121 | if (rc && errno == ENXIO) { |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 122 | memset(&loopinfo, 0, sizeof(loopinfo)); |
Eric Andersen | 76b2427 | 2006-01-30 17:30:22 +0000 | [diff] [blame] | 123 | safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE); |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 124 | loopinfo.lo_offset = offset; |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 125 | /* Associate free loop device with file. */ |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 126 | if (!ioctl(dfd, LOOP_SET_FD, ffd)) { |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 127 | if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) |
| 128 | rc = 0; |
| 129 | else |
| 130 | ioctl(dfd, LOOP_CLR_FD, 0); |
Rob Landley | 934da82 | 2006-06-25 15:29:12 +0000 | [diff] [blame] | 131 | } |
Rob Landley | aae8b34 | 2006-03-18 02:38:10 +0000 | [diff] [blame] | 132 | |
Bernhard Reutner-Fischer | 94c3331 | 2005-10-15 14:13:09 +0000 | [diff] [blame] | 133 | /* If this block device already set up right, re-use it. |
| 134 | (Yes this is racy, but associating two loop devices with the same |
| 135 | file isn't pretty either. In general, mounting the same file twice |
| 136 | without using losetup manually is problematic.) |
| 137 | */ |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 138 | } else if (strcmp(file, (char *)loopinfo.lo_file_name) != 0 |
Denis Vlasenko | 7039a66 | 2006-10-08 17:54:47 +0000 | [diff] [blame] | 139 | || offset != loopinfo.lo_offset) { |
| 140 | rc = -1; |
| 141 | } |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 142 | close(dfd); |
Rob Landley | 9085467 | 2005-12-21 16:53:57 +0000 | [diff] [blame] | 143 | try_again: |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 144 | if (*device) break; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 145 | } |
| 146 | close(ffd); |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 147 | if (!rc) { |
Denis Vlasenko | c34d355 | 2007-04-19 00:09:34 +0000 | [diff] [blame^] | 148 | if (!*device) |
| 149 | *device = xstrdup(dev); |
| 150 | return (mode == O_RDONLY) ? 1 : 0; |
Denis Vlasenko | 1385899 | 2006-10-08 12:49:22 +0000 | [diff] [blame] | 151 | } |
| 152 | return rc; |
Rob Landley | 6a6798b | 2005-08-10 20:35:54 +0000 | [diff] [blame] | 153 | } |