LXR linux/init/do_mounts

   1/*
   2 * Many of the syscalls used in this file expect some of the arguments
   3 * to be __user pointers not __kernel pointers.  To limit the sparse
   4 * noise, turn off sparse checking for this file.
   5 */
   6#ifdef __CHECKER__
   7#undef __CHECKER__
   8#warning "Sparse checking disabled for this file"
   9#endif
  10
  11#include <linux/kernel.h>
  12#include <linux/fs.h>
  13#include <linux/minix_fs.h>
  14#include <linux/ext2_fs.h>
  15#include <linux/romfs_fs.h>
  16#include <linux/cramfs_fs.h>
  17#include <linux/initrd.h>
  18#include <linux/string.h>
  19#include <linux/slab.h>
  20
  21#include "do_mounts.h"
  22#include "../fs/squashfs/squashfs_fs.h"
  23
  24#include <linux/decompress/generic.h>
  25
  26
  27int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  28
  29static int __init prompt_ramdisk(char *str)
  30{
  31        rd_prompt = simple_strtol(str,NULL,0) & 1;
  32        return 1;
  33}
  34__setup("prompt_ramdisk=", prompt_ramdisk);
  35
  36int __initdata rd_image_start;          /* starting block # of image */
  37
  38static int __init ramdisk_start_setup(char *str)
  39{
  40        rd_image_start = simple_strtol(str,NULL,0);
  41        return 1;
  42}
  43__setup("ramdisk_start=", ramdisk_start_setup);
  44
  45static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
  46
  47/*
  48 * This routine tries to find a RAM disk image to load, and returns the
  49 * number of blocks to read for a non-compressed image, 0 if the image
  50 * is a compressed image, and -1 if an image with the right magic
  51 * numbers could not be found.
  52 *
  53 * We currently check for the following magic numbers:
  54 *      minix
  55 *      ext2
  56 *      romfs
  57 *      cramfs
  58 *      squashfs
  59 *      gzip
  60 */
  61static int __init
  62identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  63{
  64        const int size = 512;
  65        struct minix_super_block *minixsb;
  66        struct romfs_super_block *romfsb;
  67        struct cramfs_super *cramfsb;
  68        struct squashfs_super_block *squashfsb;
  69        int nblocks = -1;
  70        unsigned char *buf;
  71        const char *compress_name;
  72        unsigned long n;
  73
  74        buf = kmalloc(size, GFP_KERNEL);
  75        if (!buf)
  76                return -ENOMEM;
  77
  78        minixsb = (struct minix_super_block *) buf;
  79        romfsb = (struct romfs_super_block *) buf;
  80        cramfsb = (struct cramfs_super *) buf;
  81        squashfsb = (struct squashfs_super_block *) buf;
  82        memset(buf, 0xe5, size);
  83
  84        /*
  85         * Read block 0 to test for compressed kernel
  86         */
  87        sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  88        sys_read(fd, buf, size);
  89
  90        *decompressor = decompress_method(buf, size, &compress_name);
  91        if (compress_name) {
  92                printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  93                       compress_name, start_block);
  94                if (!*decompressor)
  95                        printk(KERN_EMERG
  96                               "RAMDISK: %s decompressor not configured!\n",
  97                               compress_name);
  98                nblocks = 0;
  99                goto done;
 100        }
 101
 102        /* romfs is at block zero too */
 103        if (romfsb->word0 == ROMSB_WORD0 &&
 104            romfsb->word1 == ROMSB_WORD1) {
 105                printk(KERN_NOTICE
 106                       "RAMDISK: romfs filesystem found at block %d\n",
 107                       start_block);
 108                nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 109                goto done;
 110        }
 111
 112        if (cramfsb->magic == CRAMFS_MAGIC) {
 113                printk(KERN_NOTICE
 114                       "RAMDISK: cramfs filesystem found at block %d\n",
 115                       start_block);
 116                nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 117                goto done;
 118        }
 119
 120        /* squashfs is at block zero too */
 121        if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 122                printk(KERN_NOTICE
 123                       "RAMDISK: squashfs filesystem found at block %d\n",
 124                       start_block);
 125                nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 126                         >> BLOCK_SIZE_BITS;
 127                goto done;
 128        }
 129
 130        /*
 131         * Read 512 bytes further to check if cramfs is padded
 132         */
 133        sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 134        sys_read(fd, buf, size);
 135
 136        if (cramfsb->magic == CRAMFS_MAGIC) {
 137                printk(KERN_NOTICE
 138                       "RAMDISK: cramfs filesystem found at block %d\n",
 139                       start_block);
 140                nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 141                goto done;
 142        }
 143
 144        /*
 145         * Read block 1 to test for minix and ext2 superblock
 146         */
 147        sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 148        sys_read(fd, buf, size);
 149
 150        /* Try minix */
 151        if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 152            minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 153                printk(KERN_NOTICE
 154                       "RAMDISK: Minix filesystem found at block %d\n",
 155                       start_block);
 156                nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 157                goto done;
 158        }
 159
 160        /* Try ext2 */
 161        n = ext2_image_size(buf);
 162        if (n) {
 163                printk(KERN_NOTICE
 164                       "RAMDISK: ext2 filesystem found at block %d\n",
 165                       start_block);
 166                nblocks = n;
 167                goto done;
 168        }
 169
 170        printk(KERN_NOTICE
 171               "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 172               start_block);
 173
 174done:
 175        sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 176        kfree(buf);
 177        return nblocks;
 178}
 179
 180int __init rd_load_image(char *from)
 181{
 182        int res = 0;
 183        int in_fd, out_fd;
 184        unsigned long rd_blocks, devblocks;
 185        int nblocks, i, disk;
 186        char *buf = NULL;
 187        unsigned short rotate = 0;
 188        decompress_fn decompressor = NULL;
 189#if !defined(CONFIG_S390)
 190        char rotator[4] = { '|' , '/' , '-' , '\\' };
 191#endif
 192
 193        out_fd = sys_open("/dev/ram", O_RDWR, 0);
 194        if (out_fd < 0)
 195                goto out;
 196
 197        in_fd = sys_open(from, O_RDONLY, 0);
 198        if (in_fd < 0)
 199                goto noclose_input;
 200
 201        nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 202        if (nblocks < 0)
 203                goto done;
 204
 205        if (nblocks == 0) {
 206                if (crd_load(in_fd, out_fd, decompressor) == 0)
 207                        goto successful_load;
 208                goto done;
 209        }
 210
 211        /*
 212         * NOTE NOTE: nblocks is not actually blocks but
 213         * the number of kibibytes of data to load into a ramdisk.
 214         * So any ramdisk block size that is a multiple of 1KiB should
 215         * work when the appropriate ramdisk_blocksize is specified
 216         * on the command line.
 217         *
 218         * The default ramdisk_blocksize is 1KiB and it is generally
 219         * silly to use anything else, so make sure to use 1KiB
 220         * blocksize while generating ext2fs ramdisk-images.
 221         */
 222        if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 223                rd_blocks = 0;
 224        else
 225                rd_blocks >>= 1;
 226
 227        if (nblocks > rd_blocks) {
 228                printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 229                       nblocks, rd_blocks);
 230                goto done;
 231        }
 232
 233        /*
 234         * OK, time to copy in the data
 235         */
 236        if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 237                devblocks = 0;
 238        else
 239                devblocks >>= 1;
 240
 241        if (strcmp(from, "/initrd.image") == 0)
 242                devblocks = nblocks;
 243
 244        if (devblocks == 0) {
 245                printk(KERN_ERR "RAMDISK: could not determine device size\n");
 246                goto done;
 247        }
 248
 249        buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 250        if (!buf) {
 251                printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 252                goto done;
 253        }
 254
 255        printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 256                nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 257        for (i = 0, disk = 1; i < nblocks; i++) {
 258                if (i && (i % devblocks == 0)) {
 259                        printk("done disk #%d.\n", disk++);
 260                        rotate = 0;
 261                        if (sys_close(in_fd)) {
 262                                printk("Error closing the disk.\n");
 263                                goto noclose_input;
 264                        }
 265                        change_floppy("disk #%d", disk);
 266                        in_fd = sys_open(from, O_RDONLY, 0);
 267                        if (in_fd < 0)  {
 268                                printk("Error opening disk.\n");
 269                                goto noclose_input;
 270                        }
 271                        printk("Loading disk #%d... ", disk);
 272                }
 273                sys_read(in_fd, buf, BLOCK_SIZE);
 274                sys_write(out_fd, buf, BLOCK_SIZE);
 275#if !defined(CONFIG_S390)
 276                if (!(i % 16)) {
 277                        printk("%c\b", rotator[rotate & 0x3]);
 278                        rotate++;
 279                }
 280#endif
 281        }
 282        printk("done.\n");
 283
 284successful_load:
 285        res = 1;
 286done:
 287        sys_close(in_fd);
 288noclose_input:
 289        sys_close(out_fd);
 290out:
 291        kfree(buf);
 292        sys_unlink("/dev/ram");
 293        return res;
 294}
 295
 296int __init rd_load_disk(int n)
 297{
 298        if (rd_prompt)
 299                change_floppy("root floppy disk to be loaded into RAM disk");
 300        create_dev("/dev/root", ROOT_DEV);
 301        create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 302        return rd_load_image("/dev/root");
 303}
 304
 305static int exit_code;
 306static int decompress_error;
 307static int crd_infd, crd_outfd;
 308
 309static int __init compr_fill(void *buf, unsigned int len)
 310{
 311        int r = sys_read(crd_infd, buf, len);
 312        if (r < 0)
 313                printk(KERN_ERR "RAMDISK: error while reading compressed data");
 314        else if (r == 0)
 315                printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 316        return r;
 317}
 318
 319static int __init compr_flush(void *window, unsigned int outcnt)
 320{
 321        int written = sys_write(crd_outfd, window, outcnt);
 322        if (written != outcnt) {
 323                if (decompress_error == 0)
 324                        printk(KERN_ERR
 325                               "RAMDISK: incomplete write (%d != %d)\n",
 326                               written, outcnt);
 327                decompress_error = 1;
 328                return -1;
 329        }
 330        return outcnt;
 331}
 332
 333static void __init error(char *x)
 334{
 335        printk(KERN_ERR "%s\n", x);
 336        exit_code = 1;
 337        decompress_error = 1;
 338}
 339
 340static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 341{
 342        int result;
 343        crd_infd = in_fd;
 344        crd_outfd = out_fd;
 345        result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 346        if (decompress_error)
 347                result = 1;
 348        return result;
 349}
 350