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 */ 61 static int __init 62 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) 63 { 64 const int size = 512; 65 struct minix_super_block *minixsb; 66 struct romfs_super_block *romfsb; 67 struct cramfs_super *cramfsb; 68 struct squashfs_super_block *squashfsb; 69 int nblocks = -1; 70 unsigned char *buf; 71 const char *compress_name; 72 unsigned long n; 73 74 buf = kmalloc(size, GFP_KERNEL); 75 if (!buf) 76 return -ENOMEM; 77 78 minixsb = (struct minix_super_block *) buf; 79 romfsb = (struct romfs_super_block *) buf; 80 cramfsb = (struct cramfs_super *) buf; 81 squashfsb = (struct squashfs_super_block *) buf; 82 memset(buf, 0xe5, size); 83 84 /* 85 * Read block 0 to test for compressed kernel 86 */ 87 sys_lseek(fd, start_block * BLOCK_SIZE, 0); 88 sys_read(fd, buf, size); 89 90 *decompressor = decompress_method(buf, size, &compress_name); 91 if (compress_name) { 92 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", 93 compress_name, start_block); 94 if (!*decompressor) 95 printk(KERN_EMERG 96 "RAMDISK: %s decompressor not configured!\n", 97 compress_name); 98 nblocks = 0; 99 goto done; 100 } 101 102 /* romfs is at block zero too */ 103 if (romfsb->word0 == ROMSB_WORD0 && 104 romfsb->word1 == ROMSB_WORD1) { 105 printk(KERN_NOTICE 106 "RAMDISK: romfs filesystem found at block %d\n", 107 start_block); 108 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; 109 goto done; 110 } 111 112 if (cramfsb->magic == CRAMFS_MAGIC) { 113 printk(KERN_NOTICE 114 "RAMDISK: cramfs filesystem found at block %d\n", 115 start_block); 116 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 117 goto done; 118 } 119 120 /* squashfs is at block zero too */ 121 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { 122 printk(KERN_NOTICE 123 "RAMDISK: squashfs filesystem found at block %d\n", 124 start_block); 125 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1) 126 >> BLOCK_SIZE_BITS; 127 goto done; 128 } 129 130 /* 131 * Read 512 bytes further to check if cramfs is padded 132 */ 133 sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0); 134 sys_read(fd, buf, size); 135 136 if (cramfsb->magic == CRAMFS_MAGIC) { 137 printk(KERN_NOTICE 138 "RAMDISK: cramfs filesystem found at block %d\n", 139 start_block); 140 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 141 goto done; 142 } 143 144 /* 145 * Read block 1 to test for minix and ext2 superblock 146 */ 147 sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0); 148 sys_read(fd, buf, size); 149 150 /* Try minix */ 151 if (minixsb->s_magic == MINIX_SUPER_MAGIC || 152 minixsb->s_magic == MINIX_SUPER_MAGIC2) { 153 printk(KERN_NOTICE 154 "RAMDISK: Minix filesystem found at block %d\n", 155 start_block); 156 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; 157 goto done; 158 } 159 160 /* Try ext2 */ 161 n = ext2_image_size(buf); 162 if (n) { 163 printk(KERN_NOTICE 164 "RAMDISK: ext2 filesystem found at block %d\n", 165 start_block); 166 nblocks = n; 167 goto done; 168 } 169 170 printk(KERN_NOTICE 171 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", 172 start_block); 173 174 done: 175 sys_lseek(fd, start_block * BLOCK_SIZE, 0); 176 kfree(buf); 177 return nblocks; 178 } 179 180 int __init rd_load_image(char *from) 181 { 182 int res = 0; 183 int in_fd, out_fd; 184 unsigned long rd_blocks, devblocks; 185 int nblocks, i, disk; 186 char *buf = NULL; 187 unsigned short rotate = 0; 188 decompress_fn decompressor = NULL; 189 #if !defined(CONFIG_S390) 190 char rotator[4] = { '|' , '/' , '-' , '\\' }; 191 #endif 192 193 out_fd = sys_open("/dev/ram", O_RDWR, 0); 194 if (out_fd < 0) 195 goto out; 196 197 in_fd = sys_open(from, O_RDONLY, 0); 198 if (in_fd < 0) 199 goto noclose_input; 200 201 nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor); 202 if (nblocks < 0) 203 goto done; 204 205 if (nblocks == 0) { 206 if (crd_load(in_fd, out_fd, decompressor) == 0) 207 goto successful_load; 208 goto done; 209 } 210 211 /* 212 * NOTE NOTE: nblocks is not actually blocks but 213 * the number of kibibytes of data to load into a ramdisk. 214 * So any ramdisk block size that is a multiple of 1KiB should 215 * work when the appropriate ramdisk_blocksize is specified 216 * on the command line. 217 * 218 * The default ramdisk_blocksize is 1KiB and it is generally 219 * silly to use anything else, so make sure to use 1KiB 220 * blocksize while generating ext2fs ramdisk-images. 221 */ 222 if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0) 223 rd_blocks = 0; 224 else 225 rd_blocks >>= 1; 226 227 if (nblocks > rd_blocks) { 228 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n", 229 nblocks, rd_blocks); 230 goto done; 231 } 232 233 /* 234 * OK, time to copy in the data 235 */ 236 if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0) 237 devblocks = 0; 238 else 239 devblocks >>= 1; 240 241 if (strcmp(from, "/initrd.image") == 0) 242 devblocks = nblocks; 243 244 if (devblocks == 0) { 245 printk(KERN_ERR "RAMDISK: could not determine device size\n"); 246 goto done; 247 } 248 249 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); 250 if (!buf) { 251 printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); 252 goto done; 253 } 254 255 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ", 256 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : ""); 257 for (i = 0, disk = 1; i < nblocks; i++) { 258 if (i && (i % devblocks == 0)) { 259 printk("done disk #%d.\n", disk++); 260 rotate = 0; 261 if (sys_close(in_fd)) { 262 printk("Error closing the disk.\n"); 263 goto noclose_input; 264 } 265 change_floppy("disk #%d", disk); 266 in_fd = sys_open(from, O_RDONLY, 0); 267 if (in_fd < 0) { 268 printk("Error opening disk.\n"); 269 goto noclose_input; 270 } 271 printk("Loading disk #%d... ", disk); 272 } 273 sys_read(in_fd, buf, BLOCK_SIZE); 274 sys_write(out_fd, buf, BLOCK_SIZE); 275 #if !defined(CONFIG_S390) 276 if (!(i % 16)) { 277 printk("%c\b", rotator[rotate & 0x3]); 278 rotate++; 279 } 280 #endif 281 } 282 printk("done.\n"); 283 284 successful_load: 285 res = 1; 286 done: 287 sys_close(in_fd); 288 noclose_input: 289 sys_close(out_fd); 290 out: 291 kfree(buf); 292 sys_unlink("/dev/ram"); 293 return res; 294 } 295 296 int __init rd_load_disk(int n) 297 { 298 if (rd_prompt) 299 change_floppy("root floppy disk to be loaded into RAM disk"); 300 create_dev("/dev/root", ROOT_DEV); 301 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n)); 302 return rd_load_image("/dev/root"); 303 } 304 305 static int exit_code; 306 static int decompress_error; 307 static int crd_infd, crd_outfd; 308 309 static int __init compr_fill(void *buf, unsigned int len) 310 { 311 int r = sys_read(crd_infd, buf, len); 312 if (r < 0) 313 printk(KERN_ERR "RAMDISK: error while reading compressed data"); 314 else if (r == 0) 315 printk(KERN_ERR "RAMDISK: EOF while reading compressed data"); 316 return r; 317 } 318 319 static int __init compr_flush(void *window, unsigned int outcnt) 320 { 321 int written = sys_write(crd_outfd, window, outcnt); 322 if (written != outcnt) { 323 if (decompress_error == 0) 324 printk(KERN_ERR 325 "RAMDISK: incomplete write (%d != %d)\n", 326 written, outcnt); 327 decompress_error = 1; 328 return -1; 329 } 330 return outcnt; 331 } 332 333 static void __init error(char *x) 334 { 335 printk(KERN_ERR "%s\n", x); 336 exit_code = 1; 337 decompress_error = 1; 338 } 339 340 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco) 341 { 342 int result; 343 crd_infd = in_fd; 344 crd_outfd = out_fd; 345 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error); 346 if (decompress_error) 347 result = 1; 348 return result; 349 } 350