init/do_mounts_rd.c

   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 }