linux/init/do_mounts_rd.c
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   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 <uapi/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 *      bzip2
  61 *      lzma
  62 *      xz
  63 *      lzo
  64 *      lz4
  65 */
  66static int __init
  67identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  68{
  69        const int size = 512;
  70        struct minix_super_block *minixsb;
  71        struct romfs_super_block *romfsb;
  72        struct cramfs_super *cramfsb;
  73        struct squashfs_super_block *squashfsb;
  74        int nblocks = -1;
  75        unsigned char *buf;
  76        const char *compress_name;
  77        unsigned long n;
  78
  79        buf = kmalloc(size, GFP_KERNEL);
  80        if (!buf)
  81                return -ENOMEM;
  82
  83        minixsb = (struct minix_super_block *) buf;
  84        romfsb = (struct romfs_super_block *) buf;
  85        cramfsb = (struct cramfs_super *) buf;
  86        squashfsb = (struct squashfs_super_block *) buf;
  87        memset(buf, 0xe5, size);
  88
  89        /*
  90         * Read block 0 to test for compressed kernel
  91         */
  92        sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  93        sys_read(fd, buf, size);
  94
  95        *decompressor = decompress_method(buf, size, &compress_name);
  96        if (compress_name) {
  97                printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  98                       compress_name, start_block);
  99                if (!*decompressor)
 100                        printk(KERN_EMERG
 101                               "RAMDISK: %s decompressor not configured!\n",
 102                               compress_name);
 103                nblocks = 0;
 104                goto done;
 105        }
 106
 107        /* romfs is at block zero too */
 108        if (romfsb->word0 == ROMSB_WORD0 &&
 109            romfsb->word1 == ROMSB_WORD1) {
 110                printk(KERN_NOTICE
 111                       "RAMDISK: romfs filesystem found at block %d\n",
 112                       start_block);
 113                nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 114                goto done;
 115        }
 116
 117        if (cramfsb->magic == CRAMFS_MAGIC) {
 118                printk(KERN_NOTICE
 119                       "RAMDISK: cramfs filesystem found at block %d\n",
 120                       start_block);
 121                nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 122                goto done;
 123        }
 124
 125        /* squashfs is at block zero too */
 126        if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 127                printk(KERN_NOTICE
 128                       "RAMDISK: squashfs filesystem found at block %d\n",
 129                       start_block);
 130                nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 131                         >> BLOCK_SIZE_BITS;
 132                goto done;
 133        }
 134
 135        /*
 136         * Read 512 bytes further to check if cramfs is padded
 137         */
 138        sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 139        sys_read(fd, buf, size);
 140
 141        if (cramfsb->magic == CRAMFS_MAGIC) {
 142                printk(KERN_NOTICE
 143                       "RAMDISK: cramfs filesystem found at block %d\n",
 144                       start_block);
 145                nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 146                goto done;
 147        }
 148
 149        /*
 150         * Read block 1 to test for minix and ext2 superblock
 151         */
 152        sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 153        sys_read(fd, buf, size);
 154
 155        /* Try minix */
 156        if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 157            minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 158                printk(KERN_NOTICE
 159                       "RAMDISK: Minix filesystem found at block %d\n",
 160                       start_block);
 161                nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 162                goto done;
 163        }
 164
 165        /* Try ext2 */
 166        n = ext2_image_size(buf);
 167        if (n) {
 168                printk(KERN_NOTICE
 169                       "RAMDISK: ext2 filesystem found at block %d\n",
 170                       start_block);
 171                nblocks = n;
 172                goto done;
 173        }
 174
 175        printk(KERN_NOTICE
 176               "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 177               start_block);
 178
 179done:
 180        sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 181        kfree(buf);
 182        return nblocks;
 183}
 184
 185int __init rd_load_image(char *from)
 186{
 187        int res = 0;
 188        int in_fd, out_fd;
 189        unsigned long rd_blocks, devblocks;
 190        int nblocks, i, disk;
 191        char *buf = NULL;
 192        unsigned short rotate = 0;
 193        decompress_fn decompressor = NULL;
 194#if !defined(CONFIG_S390)
 195        char rotator[4] = { '|' , '/' , '-' , '\\' };
 196#endif
 197
 198        out_fd = sys_open("/dev/ram", O_RDWR, 0);
 199        if (out_fd < 0)
 200                goto out;
 201
 202        in_fd = sys_open(from, O_RDONLY, 0);
 203        if (in_fd < 0)
 204                goto noclose_input;
 205
 206        nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 207        if (nblocks < 0)
 208                goto done;
 209
 210        if (nblocks == 0) {
 211                if (crd_load(in_fd, out_fd, decompressor) == 0)
 212                        goto successful_load;
 213                goto done;
 214        }
 215
 216        /*
 217         * NOTE NOTE: nblocks is not actually blocks but
 218         * the number of kibibytes of data to load into a ramdisk.
 219         */
 220        if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 221                rd_blocks = 0;
 222        else
 223                rd_blocks >>= 1;
 224
 225        if (nblocks > rd_blocks) {
 226                printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 227                       nblocks, rd_blocks);
 228                goto done;
 229        }
 230
 231        /*
 232         * OK, time to copy in the data
 233         */
 234        if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 235                devblocks = 0;
 236        else
 237                devblocks >>= 1;
 238
 239        if (strcmp(from, "/initrd.image") == 0)
 240                devblocks = nblocks;
 241
 242        if (devblocks == 0) {
 243                printk(KERN_ERR "RAMDISK: could not determine device size\n");
 244                goto done;
 245        }
 246
 247        buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 248        if (!buf) {
 249                printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 250                goto done;
 251        }
 252
 253        printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 254                nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 255        for (i = 0, disk = 1; i < nblocks; i++) {
 256                if (i && (i % devblocks == 0)) {
 257                        printk("done disk #%d.\n", disk++);
 258                        rotate = 0;
 259                        if (sys_close(in_fd)) {
 260                                printk("Error closing the disk.\n");
 261                                goto noclose_input;
 262                        }
 263                        change_floppy("disk #%d", disk);
 264                        in_fd = sys_open(from, O_RDONLY, 0);
 265                        if (in_fd < 0)  {
 266                                printk("Error opening disk.\n");
 267                                goto noclose_input;
 268                        }
 269                        printk("Loading disk #%d... ", disk);
 270                }
 271                sys_read(in_fd, buf, BLOCK_SIZE);
 272                sys_write(out_fd, buf, BLOCK_SIZE);
 273#if !defined(CONFIG_S390)
 274                if (!(i % 16)) {
 275                        pr_cont("%c\b", rotator[rotate & 0x3]);
 276                        rotate++;
 277                }
 278#endif
 279        }
 280        printk("done.\n");
 281
 282successful_load:
 283        res = 1;
 284done:
 285        sys_close(in_fd);
 286noclose_input:
 287        sys_close(out_fd);
 288out:
 289        kfree(buf);
 290        sys_unlink("/dev/ram");
 291        return res;
 292}
 293
 294int __init rd_load_disk(int n)
 295{
 296        if (rd_prompt)
 297                change_floppy("root floppy disk to be loaded into RAM disk");
 298        create_dev("/dev/root", ROOT_DEV);
 299        create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 300        return rd_load_image("/dev/root");
 301}
 302
 303static int exit_code;
 304static int decompress_error;
 305static int crd_infd, crd_outfd;
 306
 307static long __init compr_fill(void *buf, unsigned long len)
 308{
 309        long r = sys_read(crd_infd, buf, len);
 310        if (r < 0)
 311                printk(KERN_ERR "RAMDISK: error while reading compressed data");
 312        else if (r == 0)
 313                printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 314        return r;
 315}
 316
 317static long __init compr_flush(void *window, unsigned long outcnt)
 318{
 319        long written = sys_write(crd_outfd, window, outcnt);
 320        if (written != outcnt) {
 321                if (decompress_error == 0)
 322                        printk(KERN_ERR
 323                               "RAMDISK: incomplete write (%ld != %ld)\n",
 324                               written, outcnt);
 325                decompress_error = 1;
 326                return -1;
 327        }
 328        return outcnt;
 329}
 330
 331static void __init error(char *x)
 332{
 333        printk(KERN_ERR "%s\n", x);
 334        exit_code = 1;
 335        decompress_error = 1;
 336}
 337
 338static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 339{
 340        int result;
 341        crd_infd = in_fd;
 342        crd_outfd = out_fd;
 343
 344        if (!deco) {
 345                pr_emerg("Invalid ramdisk decompression routine.  "
 346                         "Select appropriate config option.\n");
 347                panic("Could not decompress initial ramdisk image.");
 348        }
 349
 350        result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 351        if (decompress_error)
 352                result = 1;
 353        return result;
 354}
 355