1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/fs.h> 4 #include <linux/minix_fs.h> 5 #include <linux/ext2_fs.h> 6 #include <linux/romfs_fs.h> 7 #include <uapi/linux/cramfs_fs.h> 8 #include <linux/initrd.h> 9 #include <linux/string.h> 10 #include <linux/slab.h> 11 12 #include "do_mounts.h" 13 #include "../fs/squashfs/squashfs_fs.h" 14 15 #include <linux/decompress/generic.h> 16 17 static struct file *in_file, *out_file; 18 static loff_t in_pos, out_pos; 19 prompt_ramdisk(char * str)20 static int __init prompt_ramdisk(char *str) 21 { 22 pr_warn("ignoring the deprecated prompt_ramdisk= option\n"); 23 return 1; 24 } 25 __setup("prompt_ramdisk=", prompt_ramdisk); 26 27 int __initdata rd_image_start; /* starting block # of image */ 28 ramdisk_start_setup(char * str)29 static int __init ramdisk_start_setup(char *str) 30 { 31 rd_image_start = simple_strtol(str,NULL,0); 32 return 1; 33 } 34 __setup("ramdisk_start=", ramdisk_start_setup); 35 36 static int __init crd_load(decompress_fn deco); 37 38 /* 39 * This routine tries to find a RAM disk image to load, and returns the 40 * number of blocks to read for a non-compressed image, 0 if the image 41 * is a compressed image, and -1 if an image with the right magic 42 * numbers could not be found. 43 * 44 * We currently check for the following magic numbers: 45 * minix 46 * ext2 47 * romfs 48 * cramfs 49 * squashfs 50 * gzip 51 * bzip2 52 * lzma 53 * xz 54 * lzo 55 * lz4 56 */ 57 static int __init identify_ramdisk_image(struct file * file,loff_t pos,decompress_fn * decompressor)58 identify_ramdisk_image(struct file *file, loff_t pos, 59 decompress_fn *decompressor) 60 { 61 const int size = 512; 62 struct minix_super_block *minixsb; 63 struct romfs_super_block *romfsb; 64 struct cramfs_super *cramfsb; 65 struct squashfs_super_block *squashfsb; 66 int nblocks = -1; 67 unsigned char *buf; 68 const char *compress_name; 69 unsigned long n; 70 int start_block = rd_image_start; 71 72 buf = kmalloc(size, GFP_KERNEL); 73 if (!buf) 74 return -ENOMEM; 75 76 minixsb = (struct minix_super_block *) buf; 77 romfsb = (struct romfs_super_block *) buf; 78 cramfsb = (struct cramfs_super *) buf; 79 squashfsb = (struct squashfs_super_block *) buf; 80 memset(buf, 0xe5, size); 81 82 /* 83 * Read block 0 to test for compressed kernel 84 */ 85 pos = start_block * BLOCK_SIZE; 86 kernel_read(file, buf, size, &pos); 87 88 *decompressor = decompress_method(buf, size, &compress_name); 89 if (compress_name) { 90 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", 91 compress_name, start_block); 92 if (!*decompressor) 93 printk(KERN_EMERG 94 "RAMDISK: %s decompressor not configured!\n", 95 compress_name); 96 nblocks = 0; 97 goto done; 98 } 99 100 /* romfs is at block zero too */ 101 if (romfsb->word0 == ROMSB_WORD0 && 102 romfsb->word1 == ROMSB_WORD1) { 103 printk(KERN_NOTICE 104 "RAMDISK: romfs filesystem found at block %d\n", 105 start_block); 106 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; 107 goto done; 108 } 109 110 if (cramfsb->magic == CRAMFS_MAGIC) { 111 printk(KERN_NOTICE 112 "RAMDISK: cramfs filesystem found at block %d\n", 113 start_block); 114 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 115 goto done; 116 } 117 118 /* squashfs is at block zero too */ 119 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { 120 printk(KERN_NOTICE 121 "RAMDISK: squashfs filesystem found at block %d\n", 122 start_block); 123 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1) 124 >> BLOCK_SIZE_BITS; 125 goto done; 126 } 127 128 /* 129 * Read 512 bytes further to check if cramfs is padded 130 */ 131 pos = start_block * BLOCK_SIZE + 0x200; 132 kernel_read(file, buf, size, &pos); 133 134 if (cramfsb->magic == CRAMFS_MAGIC) { 135 printk(KERN_NOTICE 136 "RAMDISK: cramfs filesystem found at block %d\n", 137 start_block); 138 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 139 goto done; 140 } 141 142 /* 143 * Read block 1 to test for minix and ext2 superblock 144 */ 145 pos = (start_block + 1) * BLOCK_SIZE; 146 kernel_read(file, buf, size, &pos); 147 148 /* Try minix */ 149 if (minixsb->s_magic == MINIX_SUPER_MAGIC || 150 minixsb->s_magic == MINIX_SUPER_MAGIC2) { 151 printk(KERN_NOTICE 152 "RAMDISK: Minix filesystem found at block %d\n", 153 start_block); 154 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; 155 goto done; 156 } 157 158 /* Try ext2 */ 159 n = ext2_image_size(buf); 160 if (n) { 161 printk(KERN_NOTICE 162 "RAMDISK: ext2 filesystem found at block %d\n", 163 start_block); 164 nblocks = n; 165 goto done; 166 } 167 168 printk(KERN_NOTICE 169 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", 170 start_block); 171 172 done: 173 kfree(buf); 174 return nblocks; 175 } 176 nr_blocks(struct file * file)177 static unsigned long nr_blocks(struct file *file) 178 { 179 struct inode *inode = file->f_mapping->host; 180 181 if (!S_ISBLK(inode->i_mode)) 182 return 0; 183 return i_size_read(inode) >> 10; 184 } 185 rd_load_image(char * from)186 int __init rd_load_image(char *from) 187 { 188 int res = 0; 189 unsigned long rd_blocks, devblocks; 190 int nblocks, i; 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_file = filp_open("/dev/ram", O_RDWR, 0); 199 if (IS_ERR(out_file)) 200 goto out; 201 202 in_file = filp_open(from, O_RDONLY, 0); 203 if (IS_ERR(in_file)) 204 goto noclose_input; 205 206 in_pos = rd_image_start * BLOCK_SIZE; 207 nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor); 208 if (nblocks < 0) 209 goto done; 210 211 if (nblocks == 0) { 212 if (crd_load(decompressor) == 0) 213 goto successful_load; 214 goto done; 215 } 216 217 /* 218 * NOTE NOTE: nblocks is not actually blocks but 219 * the number of kibibytes of data to load into a ramdisk. 220 */ 221 rd_blocks = nr_blocks(out_file); 222 if (nblocks > rd_blocks) { 223 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n", 224 nblocks, rd_blocks); 225 goto done; 226 } 227 228 /* 229 * OK, time to copy in the data 230 */ 231 if (strcmp(from, "/initrd.image") == 0) 232 devblocks = nblocks; 233 else 234 devblocks = nr_blocks(in_file); 235 236 if (devblocks == 0) { 237 printk(KERN_ERR "RAMDISK: could not determine device size\n"); 238 goto done; 239 } 240 241 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); 242 if (!buf) { 243 printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); 244 goto done; 245 } 246 247 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ", 248 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : ""); 249 for (i = 0; i < nblocks; i++) { 250 if (i && (i % devblocks == 0)) { 251 pr_cont("done disk #1.\n"); 252 rotate = 0; 253 fput(in_file); 254 break; 255 } 256 kernel_read(in_file, buf, BLOCK_SIZE, &in_pos); 257 kernel_write(out_file, buf, BLOCK_SIZE, &out_pos); 258 #if !defined(CONFIG_S390) 259 if (!(i % 16)) { 260 pr_cont("%c\b", rotator[rotate & 0x3]); 261 rotate++; 262 } 263 #endif 264 } 265 pr_cont("done.\n"); 266 267 successful_load: 268 res = 1; 269 done: 270 fput(in_file); 271 noclose_input: 272 fput(out_file); 273 out: 274 kfree(buf); 275 init_unlink("/dev/ram"); 276 return res; 277 } 278 rd_load_disk(int n)279 int __init rd_load_disk(int n) 280 { 281 create_dev("/dev/root", ROOT_DEV); 282 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n)); 283 return rd_load_image("/dev/root"); 284 } 285 286 static int exit_code; 287 static int decompress_error; 288 compr_fill(void * buf,unsigned long len)289 static long __init compr_fill(void *buf, unsigned long len) 290 { 291 long r = kernel_read(in_file, buf, len, &in_pos); 292 if (r < 0) 293 printk(KERN_ERR "RAMDISK: error while reading compressed data"); 294 else if (r == 0) 295 printk(KERN_ERR "RAMDISK: EOF while reading compressed data"); 296 return r; 297 } 298 compr_flush(void * window,unsigned long outcnt)299 static long __init compr_flush(void *window, unsigned long outcnt) 300 { 301 long written = kernel_write(out_file, window, outcnt, &out_pos); 302 if (written != outcnt) { 303 if (decompress_error == 0) 304 printk(KERN_ERR 305 "RAMDISK: incomplete write (%ld != %ld)\n", 306 written, outcnt); 307 decompress_error = 1; 308 return -1; 309 } 310 return outcnt; 311 } 312 error(char * x)313 static void __init error(char *x) 314 { 315 printk(KERN_ERR "%s\n", x); 316 exit_code = 1; 317 decompress_error = 1; 318 } 319 crd_load(decompress_fn deco)320 static int __init crd_load(decompress_fn deco) 321 { 322 int result; 323 324 if (!deco) { 325 pr_emerg("Invalid ramdisk decompression routine. " 326 "Select appropriate config option.\n"); 327 panic("Could not decompress initial ramdisk image."); 328 } 329 330 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error); 331 if (decompress_error) 332 result = 1; 333 return result; 334 } 335