init/do_mounts_rd.c

   1
   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 <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  */
  52 static int __init
  53 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  54 {
  55         const int size = 512;
  56         struct minix_super_block *minixsb;
  57         struct ext2_super_block *ext2sb;
  58         struct romfs_super_block *romfsb;
  59         struct cramfs_super *cramfsb;
  60         struct squashfs_super_block *squashfsb;
  61         int nblocks = -1;
  62         unsigned char *buf;
  63         const char *compress_name;
  64
  65         buf = kmalloc(size, GFP_KERNEL);
  66         if (!buf)
  67                 return -ENOMEM;
  68
  69         minixsb = (struct minix_super_block *) buf;
  70         ext2sb = (struct ext2_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         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  80         sys_read(fd, buf, size);
  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         sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 126         sys_read(fd, buf, size);
 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         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 140         sys_read(fd, buf, size);
 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         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 154                 printk(KERN_NOTICE
 155                        "RAMDISK: ext2 filesystem found at block %d\n",
 156                        start_block);
 157                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 158                         le32_to_cpu(ext2sb->s_log_block_size);
 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         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 168         kfree(buf);
 169         return nblocks;
 170 }
 171
 172 int __init rd_load_image(char *from)
 173 {
 174         int res = 0;
 175         int in_fd, out_fd;
 176         unsigned long rd_blocks, devblocks;
 177         int nblocks, i, disk;
 178         char *buf = NULL;
 179         unsigned short rotate = 0;
 180         decompress_fn decompressor = NULL;
 181 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 182         char rotator[4] = { '|' , '/' , '-' , '\\' };
 183 #endif
 184
 185         out_fd = sys_open((const char __user __force *) "/dev/ram", O_RDWR, 0);
 186         if (out_fd < 0)
 187                 goto out;
 188
 189         in_fd = sys_open(from, O_RDONLY, 0);
 190         if (in_fd < 0)
 191                 goto noclose_input;
 192
 193         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 194         if (nblocks < 0)
 195                 goto done;
 196
 197         if (nblocks == 0) {
 198                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 199                         goto successful_load;
 200                 goto done;
 201         }
 202
 203         /*
 204          * NOTE NOTE: nblocks is not actually blocks but
 205          * the number of kibibytes of data to load into a ramdisk.
 206          * So any ramdisk block size that is a multiple of 1KiB should
 207          * work when the appropriate ramdisk_blocksize is specified
 208          * on the command line.
 209          *
 210          * The default ramdisk_blocksize is 1KiB and it is generally
 211          * silly to use anything else, so make sure to use 1KiB
 212          * blocksize while generating ext2fs ramdisk-images.
 213          */
 214         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 215                 rd_blocks = 0;
 216         else
 217                 rd_blocks >>= 1;
 218
 219         if (nblocks > rd_blocks) {
 220                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 221                        nblocks, rd_blocks);
 222                 goto done;
 223         }
 224
 225         /*
 226          * OK, time to copy in the data
 227          */
 228         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 229                 devblocks = 0;
 230         else
 231                 devblocks >>= 1;
 232
 233         if (strcmp(from, "/initrd.image") == 0)
 234                 devblocks = nblocks;
 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, disk = 1; i < nblocks; i++) {
 250                 if (i && (i % devblocks == 0)) {
 251                         printk("done disk #%d.\n", disk++);
 252                         rotate = 0;
 253                         if (sys_close(in_fd)) {
 254                                 printk("Error closing the disk.\n");
 255                                 goto noclose_input;
 256                         }
 257                         change_floppy("disk #%d", disk);
 258                         in_fd = sys_open(from, O_RDONLY, 0);
 259                         if (in_fd < 0)  {
 260                                 printk("Error opening disk.\n");
 261                                 goto noclose_input;
 262                         }
 263                         printk("Loading disk #%d... ", disk);
 264                 }
 265                 sys_read(in_fd, buf, BLOCK_SIZE);
 266                 sys_write(out_fd, buf, BLOCK_SIZE);
 267 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 268                 if (!(i % 16)) {
 269                         printk("%c\b", rotator[rotate & 0x3]);
 270                         rotate++;
 271                 }
 272 #endif
 273         }
 274         printk("done.\n");
 275
 276 successful_load:
 277         res = 1;
 278 done:
 279         sys_close(in_fd);
 280 noclose_input:
 281         sys_close(out_fd);
 282 out:
 283         kfree(buf);
 284         sys_unlink((const char __user __force *) "/dev/ram");
 285         return res;
 286 }
 287
 288 int __init rd_load_disk(int n)
 289 {
 290         if (rd_prompt)
 291                 change_floppy("root floppy disk to be loaded into RAM disk");
 292         create_dev("/dev/root", ROOT_DEV);
 293         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 294         return rd_load_image("/dev/root");
 295 }
 296
 297 static int exit_code;
 298 static int decompress_error;
 299 static int crd_infd, crd_outfd;
 300
 301 static int __init compr_fill(void *buf, unsigned int len)
 302 {
 303         int r = sys_read(crd_infd, buf, len);
 304         if (r < 0)
 305                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 306         else if (r == 0)
 307                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 308         return r;
 309 }
 310
 311 static int __init compr_flush(void *window, unsigned int outcnt)
 312 {
 313         int written = sys_write(crd_outfd, window, outcnt);
 314         if (written != outcnt) {
 315                 if (decompress_error == 0)
 316                         printk(KERN_ERR
 317                                "RAMDISK: incomplete write (%d != %d)\n",
 318                                written, outcnt);
 319                 decompress_error = 1;
 320                 return -1;
 321         }
 322         return outcnt;
 323 }
 324
 325 static void __init error(char *x)
 326 {
 327         printk(KERN_ERR "%s\n", x);
 328         exit_code = 1;
 329         decompress_error = 1;
 330 }
 331
 332 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 333 {
 334         int result;
 335         crd_infd = in_fd;
 336         crd_outfd = out_fd;
 337         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 338         if (decompress_error)
 339                 result = 1;
 340         return result;
 341 }