init/do_mounts_rd.c

   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
  27 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  28
  29 static 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
  36 int __initdata rd_image_start;          /* starting block # of image */
  37
  38 static 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
  45 static 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  */
  61 static int __init
  62 identify_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
 174 done:
 175         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 176         kfree(buf);
 177         return nblocks;
 178 }
 179
 180 int __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
 284 successful_load:
 285         res = 1;
 286 done:
 287         sys_close(in_fd);
 288 noclose_input:
 289         sys_close(out_fd);
 290 out:
 291         kfree(buf);
 292         sys_unlink("/dev/ram");
 293         return res;
 294 }
 295
 296 int __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
 305 static int exit_code;
 306 static int decompress_error;
 307 static int crd_infd, crd_outfd;
 308
 309 static 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
 319 static 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
 333 static void __init error(char *x)
 334 {
 335         printk(KERN_ERR "%s\n", x);
 336         exit_code = 1;
 337         decompress_error = 1;
 338 }
 339
 340 static 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 }