init/do_mounts_rd.c

   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
  18 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  19
  20 static int __init prompt_ramdisk(char *str)
  21 {
  22         rd_prompt = simple_strtol(str,NULL,0) & 1;
  23         return 1;
  24 }
  25 __setup("prompt_ramdisk=", prompt_ramdisk);
  26
  27 int __initdata rd_image_start;          /* starting block # of image */
  28
  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(int in_fd, int out_fd, 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
  58 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  59 {
  60         const int size = 512;
  61         struct minix_super_block *minixsb;
  62         struct romfs_super_block *romfsb;
  63         struct cramfs_super *cramfsb;
  64         struct squashfs_super_block *squashfsb;
  65         int nblocks = -1;
  66         unsigned char *buf;
  67         const char *compress_name;
  68         unsigned long n;
  69
  70         buf = kmalloc(size, GFP_KERNEL);
  71         if (!buf)
  72                 return -ENOMEM;
  73
  74         minixsb = (struct minix_super_block *) buf;
  75         romfsb = (struct romfs_super_block *) buf;
  76         cramfsb = (struct cramfs_super *) buf;
  77         squashfsb = (struct squashfs_super_block *) buf;
  78         memset(buf, 0xe5, size);
  79
  80         /*
  81          * Read block 0 to test for compressed kernel
  82          */
  83         ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
  84         ksys_read(fd, buf, size);
  85
  86         *decompressor = decompress_method(buf, size, &compress_name);
  87         if (compress_name) {
  88                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  89                        compress_name, start_block);
  90                 if (!*decompressor)
  91                         printk(KERN_EMERG
  92                                "RAMDISK: %s decompressor not configured!\n",
  93                                compress_name);
  94                 nblocks = 0;
  95                 goto done;
  96         }
  97
  98         /* romfs is at block zero too */
  99         if (romfsb->word0 == ROMSB_WORD0 &&
 100             romfsb->word1 == ROMSB_WORD1) {
 101                 printk(KERN_NOTICE
 102                        "RAMDISK: romfs filesystem found at block %d\n",
 103                        start_block);
 104                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 105                 goto done;
 106         }
 107
 108         if (cramfsb->magic == CRAMFS_MAGIC) {
 109                 printk(KERN_NOTICE
 110                        "RAMDISK: cramfs filesystem found at block %d\n",
 111                        start_block);
 112                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 113                 goto done;
 114         }
 115
 116         /* squashfs is at block zero too */
 117         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 118                 printk(KERN_NOTICE
 119                        "RAMDISK: squashfs filesystem found at block %d\n",
 120                        start_block);
 121                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 122                          >> BLOCK_SIZE_BITS;
 123                 goto done;
 124         }
 125
 126         /*
 127          * Read 512 bytes further to check if cramfs is padded
 128          */
 129         ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 130         ksys_read(fd, buf, size);
 131
 132         if (cramfsb->magic == CRAMFS_MAGIC) {
 133                 printk(KERN_NOTICE
 134                        "RAMDISK: cramfs filesystem found at block %d\n",
 135                        start_block);
 136                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 137                 goto done;
 138         }
 139
 140         /*
 141          * Read block 1 to test for minix and ext2 superblock
 142          */
 143         ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 144         ksys_read(fd, buf, size);
 145
 146         /* Try minix */
 147         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 148             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 149                 printk(KERN_NOTICE
 150                        "RAMDISK: Minix filesystem found at block %d\n",
 151                        start_block);
 152                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 153                 goto done;
 154         }
 155
 156         /* Try ext2 */
 157         n = ext2_image_size(buf);
 158         if (n) {
 159                 printk(KERN_NOTICE
 160                        "RAMDISK: ext2 filesystem found at block %d\n",
 161                        start_block);
 162                 nblocks = n;
 163                 goto done;
 164         }
 165
 166         printk(KERN_NOTICE
 167                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 168                start_block);
 169
 170 done:
 171         ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
 172         kfree(buf);
 173         return nblocks;
 174 }
 175
 176 int __init rd_load_image(char *from)
 177 {
 178         int res = 0;
 179         int in_fd, out_fd;
 180         unsigned long rd_blocks, devblocks;
 181         int nblocks, i, disk;
 182         char *buf = NULL;
 183         unsigned short rotate = 0;
 184         decompress_fn decompressor = NULL;
 185 #if !defined(CONFIG_S390)
 186         char rotator[4] = { '|' , '/' , '-' , '\\' };
 187 #endif
 188
 189         out_fd = ksys_open("/dev/ram", O_RDWR, 0);
 190         if (out_fd < 0)
 191                 goto out;
 192
 193         in_fd = ksys_open(from, O_RDONLY, 0);
 194         if (in_fd < 0)
 195                 goto noclose_input;
 196
 197         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 198         if (nblocks < 0)
 199                 goto done;
 200
 201         if (nblocks == 0) {
 202                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 203                         goto successful_load;
 204                 goto done;
 205         }
 206
 207         /*
 208          * NOTE NOTE: nblocks is not actually blocks but
 209          * the number of kibibytes of data to load into a ramdisk.
 210          */
 211         if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 212                 rd_blocks = 0;
 213         else
 214                 rd_blocks >>= 1;
 215
 216         if (nblocks > rd_blocks) {
 217                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 218                        nblocks, rd_blocks);
 219                 goto done;
 220         }
 221
 222         /*
 223          * OK, time to copy in the data
 224          */
 225         if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 226                 devblocks = 0;
 227         else
 228                 devblocks >>= 1;
 229
 230         if (strcmp(from, "/initrd.image") == 0)
 231                 devblocks = nblocks;
 232
 233         if (devblocks == 0) {
 234                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 235                 goto done;
 236         }
 237
 238         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 239         if (!buf) {
 240                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 241                 goto done;
 242         }
 243
 244         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 245                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 246         for (i = 0, disk = 1; i < nblocks; i++) {
 247                 if (i && (i % devblocks == 0)) {
 248                         pr_cont("done disk #%d.\n", disk++);
 249                         rotate = 0;
 250                         if (ksys_close(in_fd)) {
 251                                 printk("Error closing the disk.\n");
 252                                 goto noclose_input;
 253                         }
 254                         change_floppy("disk #%d", disk);
 255                         in_fd = ksys_open(from, O_RDONLY, 0);
 256                         if (in_fd < 0)  {
 257                                 printk("Error opening disk.\n");
 258                                 goto noclose_input;
 259                         }
 260                         printk("Loading disk #%d... ", disk);
 261                 }
 262                 ksys_read(in_fd, buf, BLOCK_SIZE);
 263                 ksys_write(out_fd, buf, BLOCK_SIZE);
 264 #if !defined(CONFIG_S390)
 265                 if (!(i % 16)) {
 266                         pr_cont("%c\b", rotator[rotate & 0x3]);
 267                         rotate++;
 268                 }
 269 #endif
 270         }
 271         pr_cont("done.\n");
 272
 273 successful_load:
 274         res = 1;
 275 done:
 276         ksys_close(in_fd);
 277 noclose_input:
 278         ksys_close(out_fd);
 279 out:
 280         kfree(buf);
 281         ksys_unlink("/dev/ram");
 282         return res;
 283 }
 284
 285 int __init rd_load_disk(int n)
 286 {
 287         if (rd_prompt)
 288                 change_floppy("root floppy disk to be loaded into RAM disk");
 289         create_dev("/dev/root", ROOT_DEV);
 290         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 291         return rd_load_image("/dev/root");
 292 }
 293
 294 static int exit_code;
 295 static int decompress_error;
 296 static int crd_infd, crd_outfd;
 297
 298 static long __init compr_fill(void *buf, unsigned long len)
 299 {
 300         long r = ksys_read(crd_infd, buf, len);
 301         if (r < 0)
 302                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 303         else if (r == 0)
 304                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 305         return r;
 306 }
 307
 308 static long __init compr_flush(void *window, unsigned long outcnt)
 309 {
 310         long written = ksys_write(crd_outfd, window, outcnt);
 311         if (written != outcnt) {
 312                 if (decompress_error == 0)
 313                         printk(KERN_ERR
 314                                "RAMDISK: incomplete write (%ld != %ld)\n",
 315                                written, outcnt);
 316                 decompress_error = 1;
 317                 return -1;
 318         }
 319         return outcnt;
 320 }
 321
 322 static void __init error(char *x)
 323 {
 324         printk(KERN_ERR "%s\n", x);
 325         exit_code = 1;
 326         decompress_error = 1;
 327 }
 328
 329 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 330 {
 331         int result;
 332         crd_infd = in_fd;
 333         crd_outfd = out_fd;
 334
 335         if (!deco) {
 336                 pr_emerg("Invalid ramdisk decompression routine.  "
 337                          "Select appropriate config option.\n");
 338                 panic("Could not decompress initial ramdisk image.");
 339         }
 340
 341         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 342         if (decompress_error)
 343                 result = 1;
 344         return result;
 345 }