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
  11 #include "do_mounts.h"
  12 #include "../fs/squashfs/squashfs_fs.h"
  13
  14 #include <linux/decompress/generic.h>
  15
  16
  17 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  18
  19 static int __init prompt_ramdisk(char *str)
  20 {
  21         rd_prompt = simple_strtol(str,NULL,0) & 1;
  22         return 1;
  23 }
  24 __setup("prompt_ramdisk=", prompt_ramdisk);
  25
  26 int __initdata rd_image_start;          /* starting block # of image */
  27
  28 static int __init ramdisk_start_setup(char *str)
  29 {
  30         rd_image_start = simple_strtol(str,NULL,0);
  31         return 1;
  32 }
  33 __setup("ramdisk_start=", ramdisk_start_setup);
  34
  35 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
  36
  37 /*
  38  * This routine tries to find a RAM disk image to load, and returns the
  39  * number of blocks to read for a non-compressed image, 0 if the image
  40  * is a compressed image, and -1 if an image with the right magic
  41  * numbers could not be found.
  42  *
  43  * We currently check for the following magic numbers:
  44  *      minix
  45  *      ext2
  46  *      romfs
  47  *      cramfs
  48  *      squashfs
  49  *      gzip
  50  */
  51 static int __init
  52 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  53 {
  54         const int size = 512;
  55         struct minix_super_block *minixsb;
  56         struct ext2_super_block *ext2sb;
  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
  64         buf = kmalloc(size, GFP_KERNEL);
  65         if (!buf)
  66                 return -1;
  67
  68         minixsb = (struct minix_super_block *) buf;
  69         ext2sb = (struct ext2_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 block 1 to test for minix and ext2 superblock
 123          */
 124         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 125         sys_read(fd, buf, size);
 126
 127         /* Try minix */
 128         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 129             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 130                 printk(KERN_NOTICE
 131                        "RAMDISK: Minix filesystem found at block %d\n",
 132                        start_block);
 133                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 134                 goto done;
 135         }
 136
 137         /* Try ext2 */
 138         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 139                 printk(KERN_NOTICE
 140                        "RAMDISK: ext2 filesystem found at block %d\n",
 141                        start_block);
 142                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 143                         le32_to_cpu(ext2sb->s_log_block_size);
 144                 goto done;
 145         }
 146
 147         printk(KERN_NOTICE
 148                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 149                start_block);
 150
 151 done:
 152         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 153         kfree(buf);
 154         return nblocks;
 155 }
 156
 157 int __init rd_load_image(char *from)
 158 {
 159         int res = 0;
 160         int in_fd, out_fd;
 161         unsigned long rd_blocks, devblocks;
 162         int nblocks, i, disk;
 163         char *buf = NULL;
 164         unsigned short rotate = 0;
 165         decompress_fn decompressor = NULL;
 166 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 167         char rotator[4] = { '|' , '/' , '-' , '\\' };
 168 #endif
 169
 170         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 171         if (out_fd < 0)
 172                 goto out;
 173
 174         in_fd = sys_open(from, O_RDONLY, 0);
 175         if (in_fd < 0)
 176                 goto noclose_input;
 177
 178         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 179         if (nblocks < 0)
 180                 goto done;
 181
 182         if (nblocks == 0) {
 183                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 184                         goto successful_load;
 185                 goto done;
 186         }
 187
 188         /*
 189          * NOTE NOTE: nblocks is not actually blocks but
 190          * the number of kibibytes of data to load into a ramdisk.
 191          * So any ramdisk block size that is a multiple of 1KiB should
 192          * work when the appropriate ramdisk_blocksize is specified
 193          * on the command line.
 194          *
 195          * The default ramdisk_blocksize is 1KiB and it is generally
 196          * silly to use anything else, so make sure to use 1KiB
 197          * blocksize while generating ext2fs ramdisk-images.
 198          */
 199         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 200                 rd_blocks = 0;
 201         else
 202                 rd_blocks >>= 1;
 203
 204         if (nblocks > rd_blocks) {
 205                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 206                        nblocks, rd_blocks);
 207                 goto done;
 208         }
 209
 210         /*
 211          * OK, time to copy in the data
 212          */
 213         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 214                 devblocks = 0;
 215         else
 216                 devblocks >>= 1;
 217
 218         if (strcmp(from, "/initrd.image") == 0)
 219                 devblocks = nblocks;
 220
 221         if (devblocks == 0) {
 222                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 223                 goto done;
 224         }
 225
 226         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 227         if (!buf) {
 228                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 229                 goto done;
 230         }
 231
 232         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 233                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 234         for (i = 0, disk = 1; i < nblocks; i++) {
 235                 if (i && (i % devblocks == 0)) {
 236                         printk("done disk #%d.\n", disk++);
 237                         rotate = 0;
 238                         if (sys_close(in_fd)) {
 239                                 printk("Error closing the disk.\n");
 240                                 goto noclose_input;
 241                         }
 242                         change_floppy("disk #%d", disk);
 243                         in_fd = sys_open(from, O_RDONLY, 0);
 244                         if (in_fd < 0)  {
 245                                 printk("Error opening disk.\n");
 246                                 goto noclose_input;
 247                         }
 248                         printk("Loading disk #%d... ", disk);
 249                 }
 250                 sys_read(in_fd, buf, BLOCK_SIZE);
 251                 sys_write(out_fd, buf, BLOCK_SIZE);
 252 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 253                 if (!(i % 16)) {
 254                         printk("%c\b", rotator[rotate & 0x3]);
 255                         rotate++;
 256                 }
 257 #endif
 258         }
 259         printk("done.\n");
 260
 261 successful_load:
 262         res = 1;
 263 done:
 264         sys_close(in_fd);
 265 noclose_input:
 266         sys_close(out_fd);
 267 out:
 268         kfree(buf);
 269         sys_unlink("/dev/ram");
 270         return res;
 271 }
 272
 273 int __init rd_load_disk(int n)
 274 {
 275         if (rd_prompt)
 276                 change_floppy("root floppy disk to be loaded into RAM disk");
 277         create_dev("/dev/root", ROOT_DEV);
 278         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 279         return rd_load_image("/dev/root");
 280 }
 281
 282 static int exit_code;
 283 static int decompress_error;
 284 static int crd_infd, crd_outfd;
 285
 286 static int __init compr_fill(void *buf, unsigned int len)
 287 {
 288         int r = sys_read(crd_infd, buf, len);
 289         if (r < 0)
 290                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 291         else if (r == 0)
 292                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 293         return r;
 294 }
 295
 296 static int __init compr_flush(void *window, unsigned int outcnt)
 297 {
 298         int written = sys_write(crd_outfd, window, outcnt);
 299         if (written != outcnt) {
 300                 if (decompress_error == 0)
 301                         printk(KERN_ERR
 302                                "RAMDISK: incomplete write (%d != %d)\n",
 303                                written, outcnt);
 304                 decompress_error = 1;
 305                 return -1;
 306         }
 307         return outcnt;
 308 }
 309
 310 static void __init error(char *x)
 311 {
 312         printk(KERN_ERR "%s\n", x);
 313         exit_code = 1;
 314         decompress_error = 1;
 315 }
 316
 317 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 318 {
 319         int result;
 320         crd_infd = in_fd;
 321         crd_outfd = out_fd;
 322         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 323         if (decompress_error)
 324                 result = 1;
 325         return result;
 326 }