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 (*decompressor) {
  83                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  84                        compress_name, start_block);
  85                 nblocks = 0;
  86                 goto done;
  87         }
  88
  89         /* romfs is at block zero too */
  90         if (romfsb->word0 == ROMSB_WORD0 &&
  91             romfsb->word1 == ROMSB_WORD1) {
  92                 printk(KERN_NOTICE
  93                        "RAMDISK: romfs filesystem found at block %d\n",
  94                        start_block);
  95                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
  96                 goto done;
  97         }
  98
  99         if (cramfsb->magic == CRAMFS_MAGIC) {
 100                 printk(KERN_NOTICE
 101                        "RAMDISK: cramfs filesystem found at block %d\n",
 102                        start_block);
 103                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 104                 goto done;
 105         }
 106
 107         /* squashfs is at block zero too */
 108         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 109                 printk(KERN_NOTICE
 110                        "RAMDISK: squashfs filesystem found at block %d\n",
 111                        start_block);
 112                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 113                          >> BLOCK_SIZE_BITS;
 114                 goto done;
 115         }
 116
 117         /*
 118          * Read block 1 to test for minix and ext2 superblock
 119          */
 120         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 121         sys_read(fd, buf, size);
 122
 123         /* Try minix */
 124         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 125             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 126                 printk(KERN_NOTICE
 127                        "RAMDISK: Minix filesystem found at block %d\n",
 128                        start_block);
 129                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 130                 goto done;
 131         }
 132
 133         /* Try ext2 */
 134         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 135                 printk(KERN_NOTICE
 136                        "RAMDISK: ext2 filesystem found at block %d\n",
 137                        start_block);
 138                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 139                         le32_to_cpu(ext2sb->s_log_block_size);
 140                 goto done;
 141         }
 142
 143         printk(KERN_NOTICE
 144                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 145                start_block);
 146
 147 done:
 148         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 149         kfree(buf);
 150         return nblocks;
 151 }
 152
 153 int __init rd_load_image(char *from)
 154 {
 155         int res = 0;
 156         int in_fd, out_fd;
 157         unsigned long rd_blocks, devblocks;
 158         int nblocks, i, disk;
 159         char *buf = NULL;
 160         unsigned short rotate = 0;
 161         decompress_fn decompressor = NULL;
 162 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 163         char rotator[4] = { '|' , '/' , '-' , '\\' };
 164 #endif
 165
 166         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 167         if (out_fd < 0)
 168                 goto out;
 169
 170         in_fd = sys_open(from, O_RDONLY, 0);
 171         if (in_fd < 0)
 172                 goto noclose_input;
 173
 174         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 175         if (nblocks < 0)
 176                 goto done;
 177
 178         if (nblocks == 0) {
 179                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 180                         goto successful_load;
 181                 goto done;
 182         }
 183
 184         /*
 185          * NOTE NOTE: nblocks is not actually blocks but
 186          * the number of kibibytes of data to load into a ramdisk.
 187          * So any ramdisk block size that is a multiple of 1KiB should
 188          * work when the appropriate ramdisk_blocksize is specified
 189          * on the command line.
 190          *
 191          * The default ramdisk_blocksize is 1KiB and it is generally
 192          * silly to use anything else, so make sure to use 1KiB
 193          * blocksize while generating ext2fs ramdisk-images.
 194          */
 195         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 196                 rd_blocks = 0;
 197         else
 198                 rd_blocks >>= 1;
 199
 200         if (nblocks > rd_blocks) {
 201                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 202                        nblocks, rd_blocks);
 203                 goto done;
 204         }
 205
 206         /*
 207          * OK, time to copy in the data
 208          */
 209         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 210                 devblocks = 0;
 211         else
 212                 devblocks >>= 1;
 213
 214         if (strcmp(from, "/initrd.image") == 0)
 215                 devblocks = nblocks;
 216
 217         if (devblocks == 0) {
 218                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 219                 goto done;
 220         }
 221
 222         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 223         if (!buf) {
 224                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 225                 goto done;
 226         }
 227
 228         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 229                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 230         for (i = 0, disk = 1; i < nblocks; i++) {
 231                 if (i && (i % devblocks == 0)) {
 232                         printk("done disk #%d.\n", disk++);
 233                         rotate = 0;
 234                         if (sys_close(in_fd)) {
 235                                 printk("Error closing the disk.\n");
 236                                 goto noclose_input;
 237                         }
 238                         change_floppy("disk #%d", disk);
 239                         in_fd = sys_open(from, O_RDONLY, 0);
 240                         if (in_fd < 0)  {
 241                                 printk("Error opening disk.\n");
 242                                 goto noclose_input;
 243                         }
 244                         printk("Loading disk #%d... ", disk);
 245                 }
 246                 sys_read(in_fd, buf, BLOCK_SIZE);
 247                 sys_write(out_fd, buf, BLOCK_SIZE);
 248 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 249                 if (!(i % 16)) {
 250                         printk("%c\b", rotator[rotate & 0x3]);
 251                         rotate++;
 252                 }
 253 #endif
 254         }
 255         printk("done.\n");
 256
 257 successful_load:
 258         res = 1;
 259 done:
 260         sys_close(in_fd);
 261 noclose_input:
 262         sys_close(out_fd);
 263 out:
 264         kfree(buf);
 265         sys_unlink("/dev/ram");
 266         return res;
 267 }
 268
 269 int __init rd_load_disk(int n)
 270 {
 271         if (rd_prompt)
 272                 change_floppy("root floppy disk to be loaded into RAM disk");
 273         create_dev("/dev/root", ROOT_DEV);
 274         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 275         return rd_load_image("/dev/root");
 276 }
 277
 278 static int exit_code;
 279 static int decompress_error;
 280 static int crd_infd, crd_outfd;
 281
 282 static int __init compr_fill(void *buf, unsigned int len)
 283 {
 284         int r = sys_read(crd_infd, buf, len);
 285         if (r < 0)
 286                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 287         else if (r == 0)
 288                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 289         return r;
 290 }
 291
 292 static int __init compr_flush(void *window, unsigned int outcnt)
 293 {
 294         int written = sys_write(crd_outfd, window, outcnt);
 295         if (written != outcnt) {
 296                 if (decompress_error == 0)
 297                         printk(KERN_ERR
 298                                "RAMDISK: incomplete write (%d != %d)\n",
 299                                written, outcnt);
 300                 decompress_error = 1;
 301                 return -1;
 302         }
 303         return outcnt;
 304 }
 305
 306 static void __init error(char *x)
 307 {
 308         printk(KERN_ERR "%s\n", x);
 309         exit_code = 1;
 310         decompress_error = 1;
 311 }
 312
 313 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 314 {
 315         int result;
 316         crd_infd = in_fd;
 317         crd_outfd = out_fd;
 318         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 319         if (decompress_error)
 320                 result = 1;
 321         return result;
 322 }