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/string_choices.h> 11 #include <linux/slab.h> 12 13 #include "do_mounts.h" 14 #include "../fs/squashfs/squashfs_fs.h" 15 16 #include <linux/decompress/generic.h> 17 18 static struct file *in_file, *out_file; 19 static loff_t in_pos, out_pos; 20 21 int __initdata rd_image_start; /* starting block # of image */ 22 23 static int __init ramdisk_start_setup(char *str) 24 { 25 pr_warn("ramdisk_start= option is deprecated and will be removed soon\n"); 26 return kstrtoint(str, 0, &rd_image_start) == 0; 27 } 28 __setup("ramdisk_start=", ramdisk_start_setup); 29 30 static int __init crd_load(decompress_fn deco); 31 32 /* 33 * This routine tries to find a RAM disk image to load, and returns the 34 * number of blocks to read for a non-compressed image, 0 if the image 35 * is a compressed image, and -1 if an image with the right magic 36 * numbers could not be found. 37 * 38 * We currently check for the following magic numbers: 39 * minix 40 * ext2 41 * romfs 42 * cramfs 43 * squashfs 44 * gzip 45 * bzip2 46 * lzma 47 * xz 48 * lzo 49 * lz4 50 */ 51 static int __init 52 identify_ramdisk_image(struct file *file, loff_t pos, 53 decompress_fn *decompressor) 54 { 55 const int size = 512; 56 struct minix_super_block *minixsb; 57 struct romfs_super_block *romfsb; 58 struct cramfs_super *cramfsb; 59 struct squashfs_super_block *squashfsb; 60 int nblocks = -1; 61 unsigned char *buf; 62 const char *compress_name; 63 unsigned long n; 64 int start_block = rd_image_start; 65 66 buf = kmalloc(size, GFP_KERNEL); 67 if (!buf) 68 return -ENOMEM; 69 70 minixsb = (struct minix_super_block *) buf; 71 romfsb = (struct romfs_super_block *) buf; 72 cramfsb = (struct cramfs_super *) buf; 73 squashfsb = (struct squashfs_super_block *) buf; 74 memset(buf, 0xe5, size); 75 76 /* 77 * Read block 0 to test for compressed kernel 78 */ 79 pos = start_block * BLOCK_SIZE; 80 kernel_read(file, buf, size, &pos); 81 82 *decompressor = decompress_method(buf, size, &compress_name); 83 if (compress_name) { 84 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", 85 compress_name, start_block); 86 if (!*decompressor) 87 printk(KERN_EMERG 88 "RAMDISK: %s decompressor not configured!\n", 89 compress_name); 90 nblocks = 0; 91 goto done; 92 } 93 94 /* romfs is at block zero too */ 95 if (romfsb->word0 == ROMSB_WORD0 && 96 romfsb->word1 == ROMSB_WORD1) { 97 printk(KERN_NOTICE 98 "RAMDISK: romfs filesystem found at block %d\n", 99 start_block); 100 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; 101 goto done; 102 } 103 104 if (cramfsb->magic == CRAMFS_MAGIC) { 105 printk(KERN_NOTICE 106 "RAMDISK: cramfs filesystem found at block %d\n", 107 start_block); 108 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 109 goto done; 110 } 111 112 /* squashfs is at block zero too */ 113 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { 114 printk(KERN_NOTICE 115 "RAMDISK: squashfs filesystem found at block %d\n", 116 start_block); 117 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1) 118 >> BLOCK_SIZE_BITS; 119 goto done; 120 } 121 122 /* 123 * Read 512 bytes further to check if cramfs is padded 124 */ 125 pos = start_block * BLOCK_SIZE + 0x200; 126 kernel_read(file, buf, size, &pos); 127 128 if (cramfsb->magic == CRAMFS_MAGIC) { 129 printk(KERN_NOTICE 130 "RAMDISK: cramfs filesystem found at block %d\n", 131 start_block); 132 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 133 goto done; 134 } 135 136 /* 137 * Read block 1 to test for minix and ext2 superblock 138 */ 139 pos = (start_block + 1) * BLOCK_SIZE; 140 kernel_read(file, buf, size, &pos); 141 142 /* Try minix */ 143 if (minixsb->s_magic == MINIX_SUPER_MAGIC || 144 minixsb->s_magic == MINIX_SUPER_MAGIC2) { 145 printk(KERN_NOTICE 146 "RAMDISK: Minix filesystem found at block %d\n", 147 start_block); 148 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; 149 goto done; 150 } 151 152 /* Try ext2 */ 153 n = ext2_image_size(buf); 154 if (n) { 155 printk(KERN_NOTICE 156 "RAMDISK: ext2 filesystem found at block %d\n", 157 start_block); 158 nblocks = n; 159 goto done; 160 } 161 162 printk(KERN_NOTICE 163 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", 164 start_block); 165 166 done: 167 kfree(buf); 168 return nblocks; 169 } 170 171 static unsigned long nr_blocks(struct file *file) 172 { 173 struct inode *inode = file->f_mapping->host; 174 175 if (!S_ISBLK(inode->i_mode)) 176 return 0; 177 return i_size_read(inode) >> 10; 178 } 179 180 int __init rd_load_image(void) 181 { 182 int res = 0; 183 unsigned long rd_blocks, devblocks, nr_disks; 184 int nblocks, i; 185 char *buf = NULL; 186 unsigned short rotate = 0; 187 decompress_fn decompressor = NULL; 188 char rotator[4] = { '|' , '/' , '-' , '\\' }; 189 190 out_file = filp_open("/dev/ram", O_RDWR, 0); 191 if (IS_ERR(out_file)) 192 goto out; 193 194 in_file = filp_open("/initrd.image", O_RDONLY, 0); 195 if (IS_ERR(in_file)) 196 goto noclose_input; 197 198 in_pos = rd_image_start * BLOCK_SIZE; 199 nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor); 200 if (nblocks < 0) 201 goto done; 202 203 if (nblocks == 0) { 204 if (crd_load(decompressor) == 0) 205 goto successful_load; 206 goto done; 207 } 208 209 /* 210 * NOTE NOTE: nblocks is not actually blocks but 211 * the number of kibibytes of data to load into a ramdisk. 212 */ 213 rd_blocks = nr_blocks(out_file); 214 if (nblocks > rd_blocks) { 215 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n", 216 nblocks, rd_blocks); 217 goto done; 218 } 219 220 /* 221 * OK, time to copy in the data 222 */ 223 devblocks = nblocks; 224 225 if (devblocks == 0) { 226 printk(KERN_ERR "RAMDISK: could not determine device size\n"); 227 goto done; 228 } 229 230 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); 231 if (!buf) { 232 printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); 233 goto done; 234 } 235 236 nr_disks = (nblocks - 1) / devblocks + 1; 237 pr_notice("RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ", 238 nblocks, nr_disks, str_plural(nr_disks)); 239 for (i = 0; i < nblocks; i++) { 240 if (i && (i % devblocks == 0)) { 241 pr_cont("done disk #1.\n"); 242 rotate = 0; 243 fput(in_file); 244 break; 245 } 246 kernel_read(in_file, buf, BLOCK_SIZE, &in_pos); 247 kernel_write(out_file, buf, BLOCK_SIZE, &out_pos); 248 if (!IS_ENABLED(CONFIG_S390) && !(i % 16)) { 249 pr_cont("%c\b", rotator[rotate & 0x3]); 250 rotate++; 251 } 252 } 253 pr_cont("done.\n"); 254 255 successful_load: 256 res = 1; 257 done: 258 fput(in_file); 259 noclose_input: 260 fput(out_file); 261 out: 262 kfree(buf); 263 init_unlink("/dev/ram"); 264 return res; 265 } 266 267 static int exit_code; 268 static int decompress_error; 269 270 static long __init compr_fill(void *buf, unsigned long len) 271 { 272 long r = kernel_read(in_file, buf, len, &in_pos); 273 if (r < 0) 274 printk(KERN_ERR "RAMDISK: error while reading compressed data"); 275 else if (r == 0) 276 printk(KERN_ERR "RAMDISK: EOF while reading compressed data"); 277 return r; 278 } 279 280 static long __init compr_flush(void *window, unsigned long outcnt) 281 { 282 long written = kernel_write(out_file, window, outcnt, &out_pos); 283 if (written != outcnt) { 284 if (decompress_error == 0) 285 printk(KERN_ERR 286 "RAMDISK: incomplete write (%ld != %ld)\n", 287 written, outcnt); 288 decompress_error = 1; 289 return -1; 290 } 291 return outcnt; 292 } 293 294 static void __init error(char *x) 295 { 296 printk(KERN_ERR "%s\n", x); 297 exit_code = 1; 298 decompress_error = 1; 299 } 300 301 static int __init crd_load(decompress_fn deco) 302 { 303 int result; 304 305 if (!deco) { 306 pr_emerg("Invalid ramdisk decompression routine. " 307 "Select appropriate config option.\n"); 308 panic("Could not decompress initial ramdisk image."); 309 } 310 311 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error); 312 if (decompress_error) 313 result = 1; 314 return result; 315 } 316