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 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
  65         buf = kmalloc(size, GFP_KERNEL);
  66         if (!buf)
  67                 return -ENOMEM;
  68
  69         minixsb = (struct minix_super_block *) buf;
  70         romfsb = (struct romfs_super_block *) buf;
  71         cramfsb = (struct cramfs_super *) buf;
  72         squashfsb = (struct squashfs_super_block *) buf;
  73         memset(buf, 0xe5, size);
  74
  75         /*
  76          * Read block 0 to test for compressed kernel
  77          */
  78         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  79         sys_read(fd, buf, size);
  80
  81         *decompressor = decompress_method(buf, size, &compress_name);
  82         if (compress_name) {
  83                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  84                        compress_name, start_block);
  85                 if (!*decompressor)
  86                         printk(KERN_EMERG
  87                                "RAMDISK: %s decompressor not configured!\n",
  88                                compress_name);
  89                 nblocks = 0;
  90                 goto done;
  91         }
  92
  93         /* romfs is at block zero too */
  94         if (romfsb->word0 == ROMSB_WORD0 &&
  95             romfsb->word1 == ROMSB_WORD1) {
  96                 printk(KERN_NOTICE
  97                        "RAMDISK: romfs filesystem found at block %d\n",
  98                        start_block);
  99                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 100                 goto done;
 101         }
 102
 103         if (cramfsb->magic == CRAMFS_MAGIC) {
 104                 printk(KERN_NOTICE
 105                        "RAMDISK: cramfs filesystem found at block %d\n",
 106                        start_block);
 107                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 108                 goto done;
 109         }
 110
 111         /* squashfs is at block zero too */
 112         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 113                 printk(KERN_NOTICE
 114                        "RAMDISK: squashfs filesystem found at block %d\n",
 115                        start_block);
 116                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 117                          >> BLOCK_SIZE_BITS;
 118                 goto done;
 119         }
 120
 121         /*
 122          * Read 512 bytes further to check if cramfs is padded
 123          */
 124         sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 125         sys_read(fd, buf, size);
 126
 127         if (cramfsb->magic == CRAMFS_MAGIC) {
 128                 printk(KERN_NOTICE
 129                        "RAMDISK: cramfs filesystem found at block %d\n",
 130                        start_block);
 131                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 132                 goto done;
 133         }
 134
 135         /*
 136          * Read block 1 to test for minix and ext2 superblock
 137          */
 138         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 139         sys_read(fd, buf, size);
 140
 141         /* Try minix */
 142         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 143             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 144                 printk(KERN_NOTICE
 145                        "RAMDISK: Minix filesystem found at block %d\n",
 146                        start_block);
 147                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 148                 goto done;
 149         }
 150
 151         /* Try ext2 */
 152         n = ext2_image_size(buf);
 153         if (n) {
 154                 printk(KERN_NOTICE
 155                        "RAMDISK: ext2 filesystem found at block %d\n",
 156                        start_block);
 157                 nblocks = n;
 158                 goto done;
 159         }
 160
 161         printk(KERN_NOTICE
 162                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 163                start_block);
 164
 165 done:
 166         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 167         kfree(buf);
 168         return nblocks;
 169 }
 170
 171 int __init rd_load_image(char *from)
 172 {
 173         int res = 0;
 174         int in_fd, out_fd;
 175         unsigned long rd_blocks, devblocks;
 176         int nblocks, i, disk;
 177         char *buf = NULL;
 178         unsigned short rotate = 0;
 179         decompress_fn decompressor = NULL;
 180 #if !defined(CONFIG_S390)
 181         char rotator[4] = { '|' , '/' , '-' , '\\' };
 182 #endif
 183
 184         out_fd = sys_open((const char __user __force *) "/dev/ram", O_RDWR, 0);
 185         if (out_fd < 0)
 186                 goto out;
 187
 188         in_fd = sys_open(from, O_RDONLY, 0);
 189         if (in_fd < 0)
 190                 goto noclose_input;
 191
 192         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 193         if (nblocks < 0)
 194                 goto done;
 195
 196         if (nblocks == 0) {
 197                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 198                         goto successful_load;
 199                 goto done;
 200         }
 201
 202         /*
 203          * NOTE NOTE: nblocks is not actually blocks but
 204          * the number of kibibytes of data to load into a ramdisk.
 205          * So any ramdisk block size that is a multiple of 1KiB should
 206          * work when the appropriate ramdisk_blocksize is specified
 207          * on the command line.
 208          *
 209          * The default ramdisk_blocksize is 1KiB and it is generally
 210          * silly to use anything else, so make sure to use 1KiB
 211          * blocksize while generating ext2fs ramdisk-images.
 212          */
 213         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 214                 rd_blocks = 0;
 215         else
 216                 rd_blocks >>= 1;
 217
 218         if (nblocks > rd_blocks) {
 219                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 220                        nblocks, rd_blocks);
 221                 goto done;
 222         }
 223
 224         /*
 225          * OK, time to copy in the data
 226          */
 227         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 228                 devblocks = 0;
 229         else
 230                 devblocks >>= 1;
 231
 232         if (strcmp(from, "/initrd.image") == 0)
 233                 devblocks = nblocks;
 234
 235         if (devblocks == 0) {
 236                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 237                 goto done;
 238         }
 239
 240         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 241         if (!buf) {
 242                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 243                 goto done;
 244         }
 245
 246         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 247                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 248         for (i = 0, disk = 1; i < nblocks; i++) {
 249                 if (i && (i % devblocks == 0)) {
 250                         printk("done disk #%d.\n", disk++);
 251                         rotate = 0;
 252                         if (sys_close(in_fd)) {
 253                                 printk("Error closing the disk.\n");
 254                                 goto noclose_input;
 255                         }
 256                         change_floppy("disk #%d", disk);
 257                         in_fd = sys_open(from, O_RDONLY, 0);
 258                         if (in_fd < 0)  {
 259                                 printk("Error opening disk.\n");
 260                                 goto noclose_input;
 261                         }
 262                         printk("Loading disk #%d... ", disk);
 263                 }
 264                 sys_read(in_fd, buf, BLOCK_SIZE);
 265                 sys_write(out_fd, buf, BLOCK_SIZE);
 266 #if !defined(CONFIG_S390)
 267                 if (!(i % 16)) {
 268                         printk("%c\b", rotator[rotate & 0x3]);
 269                         rotate++;
 270                 }
 271 #endif
 272         }
 273         printk("done.\n");
 274
 275 successful_load:
 276         res = 1;
 277 done:
 278         sys_close(in_fd);
 279 noclose_input:
 280         sys_close(out_fd);
 281 out:
 282         kfree(buf);
 283         sys_unlink((const char __user __force *) "/dev/ram");
 284         return res;
 285 }
 286
 287 int __init rd_load_disk(int n)
 288 {
 289         if (rd_prompt)
 290                 change_floppy("root floppy disk to be loaded into RAM disk");
 291         create_dev("/dev/root", ROOT_DEV);
 292         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 293         return rd_load_image("/dev/root");
 294 }
 295
 296 static int exit_code;
 297 static int decompress_error;
 298 static int crd_infd, crd_outfd;
 299
 300 static int __init compr_fill(void *buf, unsigned int len)
 301 {
 302         int r = sys_read(crd_infd, buf, len);
 303         if (r < 0)
 304                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 305         else if (r == 0)
 306                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 307         return r;
 308 }
 309
 310 static int __init compr_flush(void *window, unsigned int outcnt)
 311 {
 312         int written = sys_write(crd_outfd, window, outcnt);
 313         if (written != outcnt) {
 314                 if (decompress_error == 0)
 315                         printk(KERN_ERR
 316                                "RAMDISK: incomplete write (%d != %d)\n",
 317                                written, outcnt);
 318                 decompress_error = 1;
 319                 return -1;
 320         }
 321         return outcnt;
 322 }
 323
 324 static void __init error(char *x)
 325 {
 326         printk(KERN_ERR "%s\n", x);
 327         exit_code = 1;
 328         decompress_error = 1;
 329 }
 330
 331 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 332 {
 333         int result;
 334         crd_infd = in_fd;
 335         crd_outfd = out_fd;
 336         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 337         if (decompress_error)
 338                 result = 1;
 339         return result;
 340 }