LXR linux/init/do_mounts

   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
  17int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  18
  19static 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
  26int __initdata rd_image_start;          /* starting block # of image */
  27
  28static 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
  35static 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 */
  51static int __init
  52identify_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
 151done:
 152        sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 153        kfree(buf);
 154        return nblocks;
 155}
 156
 157int __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
 261successful_load:
 262        res = 1;
 263done:
 264        sys_close(in_fd);
 265noclose_input:
 266        sys_close(out_fd);
 267out:
 268        kfree(buf);
 269        sys_unlink("/dev/ram");
 270        return res;
 271}
 272
 273int __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
 282static int exit_code;
 283static int decompress_error;
 284static int crd_infd, crd_outfd;
 285
 286static 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
 296static 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
 310static void __init error(char *x)
 311{
 312        printk(KERN_ERR "%s\n", x);
 313        exit_code = 1;
 314        decompress_error = 1;
 315}
 316
 317static 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}
 327