1 /* 2 * Many of the syscalls used in this file expect some of the arguments 3 * to be __user pointers not __kernel pointers. To limit the sparse 4 * noise, turn off sparse checking for this file. 5 */ 6 #ifdef __CHECKER__ 7 #undef __CHECKER__ 8 #warning "Sparse checking disabled for this file" 9 #endif 10 11 #include <linux/kernel.h> 12 #include <linux/fs.h> 13 #include <linux/minix_fs.h> 14 #include <linux/ext2_fs.h> 15 #include <linux/romfs_fs.h> 16 #include <linux/cramfs_fs.h> 17 #include <linux/initrd.h> 18 #include <linux/string.h> 19 #include <linux/slab.h> 20 21 #include "do_mounts.h" 22 #include "../fs/squashfs/squashfs_fs.h" 23 24 #include <linux/decompress/generic.h> 25 26 27 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */ 28 29 static int __init prompt_ramdisk(char *str) 30 { 31 rd_prompt = simple_strtol(str,NULL,0) & 1; 32 return 1; 33 } 34 __setup("prompt_ramdisk=", prompt_ramdisk); 35 36 int __initdata rd_image_start; /* starting block # of image */ 37 38 static int __init ramdisk_start_setup(char *str) 39 { 40 rd_image_start = simple_strtol(str,NULL,0); 41 return 1; 42 } 43 __setup("ramdisk_start=", ramdisk_start_setup); 44 45 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco); 46 47 /* 48 * This routine tries to find a RAM disk image to load, and returns the 49 * number of blocks to read for a non-compressed image, 0 if the image 50 * is a compressed image, and -1 if an image with the right magic 51 * numbers could not be found. 52 * 53 * We currently check for the following magic numbers: 54 * minix 55 * ext2 56 * romfs 57 * cramfs 58 * squashfs 59 * gzip 60 * bzip2 61 * lzma 62 * xz 63 * lzo 64 * lz4 65 */ 66 static int __init 67 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) 68 { 69 const int size = 512; 70 struct minix_super_block *minixsb; 71 struct romfs_super_block *romfsb; 72 struct cramfs_super *cramfsb; 73 struct squashfs_super_block *squashfsb; 74 int nblocks = -1; 75 unsigned char *buf; 76 const char *compress_name; 77 unsigned long n; 78 79 buf = kmalloc(size, GFP_KERNEL); 80 if (!buf) 81 return -ENOMEM; 82 83 minixsb = (struct minix_super_block *) buf; 84 romfsb = (struct romfs_super_block *) buf; 85 cramfsb = (struct cramfs_super *) buf; 86 squashfsb = (struct squashfs_super_block *) buf; 87 memset(buf, 0xe5, size); 88 89 /* 90 * Read block 0 to test for compressed kernel 91 */ 92 sys_lseek(fd, start_block * BLOCK_SIZE, 0); 93 sys_read(fd, buf, size); 94 95 *decompressor = decompress_method(buf, size, &compress_name); 96 if (compress_name) { 97 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", 98 compress_name, start_block); 99 if (!*decompressor) 100 printk(KERN_EMERG 101 "RAMDISK: %s decompressor not configured!\n", 102 compress_name); 103 nblocks = 0; 104 goto done; 105 } 106 107 /* romfs is at block zero too */ 108 if (romfsb->word0 == ROMSB_WORD0 && 109 romfsb->word1 == ROMSB_WORD1) { 110 printk(KERN_NOTICE 111 "RAMDISK: romfs filesystem found at block %d\n", 112 start_block); 113 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; 114 goto done; 115 } 116 117 if (cramfsb->magic == CRAMFS_MAGIC) { 118 printk(KERN_NOTICE 119 "RAMDISK: cramfs filesystem found at block %d\n", 120 start_block); 121 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 122 goto done; 123 } 124 125 /* squashfs is at block zero too */ 126 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { 127 printk(KERN_NOTICE 128 "RAMDISK: squashfs filesystem found at block %d\n", 129 start_block); 130 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1) 131 >> BLOCK_SIZE_BITS; 132 goto done; 133 } 134 135 /* 136 * Read 512 bytes further to check if cramfs is padded 137 */ 138 sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0); 139 sys_read(fd, buf, size); 140 141 if (cramfsb->magic == CRAMFS_MAGIC) { 142 printk(KERN_NOTICE 143 "RAMDISK: cramfs filesystem found at block %d\n", 144 start_block); 145 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 146 goto done; 147 } 148 149 /* 150 * Read block 1 to test for minix and ext2 superblock 151 */ 152 sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0); 153 sys_read(fd, buf, size); 154 155 /* Try minix */ 156 if (minixsb->s_magic == MINIX_SUPER_MAGIC || 157 minixsb->s_magic == MINIX_SUPER_MAGIC2) { 158 printk(KERN_NOTICE 159 "RAMDISK: Minix filesystem found at block %d\n", 160 start_block); 161 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; 162 goto done; 163 } 164 165 /* Try ext2 */ 166 n = ext2_image_size(buf); 167 if (n) { 168 printk(KERN_NOTICE 169 "RAMDISK: ext2 filesystem found at block %d\n", 170 start_block); 171 nblocks = n; 172 goto done; 173 } 174 175 printk(KERN_NOTICE 176 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", 177 start_block); 178 179 done: 180 sys_lseek(fd, start_block * BLOCK_SIZE, 0); 181 kfree(buf); 182 return nblocks; 183 } 184 185 int __init rd_load_image(char *from) 186 { 187 int res = 0; 188 int in_fd, out_fd; 189 unsigned long rd_blocks, devblocks; 190 int nblocks, i, disk; 191 char *buf = NULL; 192 unsigned short rotate = 0; 193 decompress_fn decompressor = NULL; 194 #if !defined(CONFIG_S390) 195 char rotator[4] = { '|' , '/' , '-' , '\\' }; 196 #endif 197 198 out_fd = sys_open("/dev/ram", O_RDWR, 0); 199 if (out_fd < 0) 200 goto out; 201 202 in_fd = sys_open(from, O_RDONLY, 0); 203 if (in_fd < 0) 204 goto noclose_input; 205 206 nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor); 207 if (nblocks < 0) 208 goto done; 209 210 if (nblocks == 0) { 211 if (crd_load(in_fd, out_fd, decompressor) == 0) 212 goto successful_load; 213 goto done; 214 } 215 216 /* 217 * NOTE NOTE: nblocks is not actually blocks but 218 * the number of kibibytes of data to load into a ramdisk. 219 * So any ramdisk block size that is a multiple of 1KiB should 220 * work when the appropriate ramdisk_blocksize is specified 221 * on the command line. 222 * 223 * The default ramdisk_blocksize is 1KiB and it is generally 224 * silly to use anything else, so make sure to use 1KiB 225 * blocksize while generating ext2fs ramdisk-images. 226 */ 227 if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0) 228 rd_blocks = 0; 229 else 230 rd_blocks >>= 1; 231 232 if (nblocks > rd_blocks) { 233 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n", 234 nblocks, rd_blocks); 235 goto done; 236 } 237 238 /* 239 * OK, time to copy in the data 240 */ 241 if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0) 242 devblocks = 0; 243 else 244 devblocks >>= 1; 245 246 if (strcmp(from, "/initrd.image") == 0) 247 devblocks = nblocks; 248 249 if (devblocks == 0) { 250 printk(KERN_ERR "RAMDISK: could not determine device size\n"); 251 goto done; 252 } 253 254 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); 255 if (!buf) { 256 printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); 257 goto done; 258 } 259 260 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ", 261 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : ""); 262 for (i = 0, disk = 1; i < nblocks; i++) { 263 if (i && (i % devblocks == 0)) { 264 printk("done disk #%d.\n", disk++); 265 rotate = 0; 266 if (sys_close(in_fd)) { 267 printk("Error closing the disk.\n"); 268 goto noclose_input; 269 } 270 change_floppy("disk #%d", disk); 271 in_fd = sys_open(from, O_RDONLY, 0); 272 if (in_fd < 0) { 273 printk("Error opening disk.\n"); 274 goto noclose_input; 275 } 276 printk("Loading disk #%d... ", disk); 277 } 278 sys_read(in_fd, buf, BLOCK_SIZE); 279 sys_write(out_fd, buf, BLOCK_SIZE); 280 #if !defined(CONFIG_S390) 281 if (!(i % 16)) { 282 printk("%c\b", rotator[rotate & 0x3]); 283 rotate++; 284 } 285 #endif 286 } 287 printk("done.\n"); 288 289 successful_load: 290 res = 1; 291 done: 292 sys_close(in_fd); 293 noclose_input: 294 sys_close(out_fd); 295 out: 296 kfree(buf); 297 sys_unlink("/dev/ram"); 298 return res; 299 } 300 301 int __init rd_load_disk(int n) 302 { 303 if (rd_prompt) 304 change_floppy("root floppy disk to be loaded into RAM disk"); 305 create_dev("/dev/root", ROOT_DEV); 306 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n)); 307 return rd_load_image("/dev/root"); 308 } 309 310 static int exit_code; 311 static int decompress_error; 312 static int crd_infd, crd_outfd; 313 314 static int __init compr_fill(void *buf, unsigned int len) 315 { 316 int r = sys_read(crd_infd, buf, len); 317 if (r < 0) 318 printk(KERN_ERR "RAMDISK: error while reading compressed data"); 319 else if (r == 0) 320 printk(KERN_ERR "RAMDISK: EOF while reading compressed data"); 321 return r; 322 } 323 324 static int __init compr_flush(void *window, unsigned int outcnt) 325 { 326 int written = sys_write(crd_outfd, window, outcnt); 327 if (written != outcnt) { 328 if (decompress_error == 0) 329 printk(KERN_ERR 330 "RAMDISK: incomplete write (%d != %d)\n", 331 written, outcnt); 332 decompress_error = 1; 333 return -1; 334 } 335 return outcnt; 336 } 337 338 static void __init error(char *x) 339 { 340 printk(KERN_ERR "%s\n", x); 341 exit_code = 1; 342 decompress_error = 1; 343 } 344 345 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco) 346 { 347 int result; 348 crd_infd = in_fd; 349 crd_outfd = out_fd; 350 351 if (!deco) { 352 pr_emerg("Invalid ramdisk decompression routine. " 353 "Select appropriate config option.\n"); 354 panic("Could not decompress initial ramdisk image."); 355 } 356 357 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error); 358 if (decompress_error) 359 result = 1; 360 return result; 361 } 362