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 #include <linux/slab.h>
  11
  12 #include "do_mounts.h"
  13 #include "../fs/squashfs/squashfs_fs.h"
  14
  15 #include <linux/decompress/generic.h>
  16
  17
  18 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  19
  20 static int __init prompt_ramdisk(char *str)
  21 {
  22         rd_prompt = simple_strtol(str,NULL,0) & 1;
  23         return 1;
  24 }
  25 __setup("prompt_ramdisk=", prompt_ramdisk);
  26
  27 int __initdata rd_image_start;          /* starting block # of image */
  28
  29 static int __init ramdisk_start_setup(char *str)
  30 {
  31         rd_image_start = simple_strtol(str,NULL,0);
  32         return 1;
  33 }
  34 __setup("ramdisk_start=", ramdisk_start_setup);
  35
  36 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
  37
  38 /*
  39  * This routine tries to find a RAM disk image to load, and returns the
  40  * number of blocks to read for a non-compressed image, 0 if the image
  41  * is a compressed image, and -1 if an image with the right magic
  42  * numbers could not be found.
  43  *
  44  * We currently check for the following magic numbers:
  45  *      minix
  46  *      ext2
  47  *      romfs
  48  *      cramfs
  49  *      squashfs
  50  *      gzip
  51  */
  52 static int __init
  53 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  54 {
  55         const int size = 512;
  56         struct minix_super_block *minixsb;
  57         struct ext2_super_block *ext2sb;
  58         struct romfs_super_block *romfsb;
  59         struct cramfs_super *cramfsb;
  60         struct squashfs_super_block *squashfsb;
  61         int nblocks = -1;
  62         unsigned char *buf;
  63         const char *compress_name;
  64
  65         buf = kmalloc(size, GFP_KERNEL);
  66         if (!buf)
  67                 return -ENOMEM;
  68
  69         minixsb = (struct minix_super_block *) buf;
  70         ext2sb = (struct ext2_super_block *) buf;
  71         romfsb = (struct romfs_super_block *) buf;
  72         cramfsb = (struct cramfs_super *) buf;
  73         squashfsb = (struct squashfs_super_block *) buf;
  74         memset(buf, 0xe5, size);
  75
  76         /*
  77          * Read block 0 to test for compressed kernel
  78          */
  79         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  80         sys_read(fd, buf, size);
  81
  82         *decompressor = decompress_method(buf, size, &compress_name);
  83         if (compress_name) {
  84                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  85                        compress_name, start_block);
  86                 if (!*decompressor)
  87                         printk(KERN_EMERG
  88                                "RAMDISK: %s decompressor not configured!\n",
  89                                compress_name);
  90                 nblocks = 0;
  91                 goto done;
  92         }
  93
  94         /* romfs is at block zero too */
  95         if (romfsb->word0 == ROMSB_WORD0 &&
  96             romfsb->word1 == ROMSB_WORD1) {
  97                 printk(KERN_NOTICE
  98                        "RAMDISK: romfs filesystem found at block %d\n",
  99                        start_block);
 100                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 101                 goto done;
 102         }
 103
 104         if (cramfsb->magic == CRAMFS_MAGIC) {
 105                 printk(KERN_NOTICE
 106                        "RAMDISK: cramfs filesystem found at block %d\n",
 107                        start_block);
 108                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 109                 goto done;
 110         }
 111
 112         /* squashfs is at block zero too */
 113         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 114                 printk(KERN_NOTICE
 115                        "RAMDISK: squashfs filesystem found at block %d\n",
 116                        start_block);
 117                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 118                          >> BLOCK_SIZE_BITS;
 119                 goto done;
 120         }
 121
 122         /*
 123          * Read block 1 to test for minix and ext2 superblock
 124          */
 125         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 126         sys_read(fd, buf, size);
 127
 128         /* Try minix */
 129         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 130             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 131                 printk(KERN_NOTICE
 132                        "RAMDISK: Minix filesystem found at block %d\n",
 133                        start_block);
 134                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 135                 goto done;
 136         }
 137
 138         /* Try ext2 */
 139         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 140                 printk(KERN_NOTICE
 141                        "RAMDISK: ext2 filesystem found at block %d\n",
 142                        start_block);
 143                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 144                         le32_to_cpu(ext2sb->s_log_block_size);
 145                 goto done;
 146         }
 147
 148         printk(KERN_NOTICE
 149                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 150                start_block);
 151
 152 done:
 153         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 154         kfree(buf);
 155         return nblocks;
 156 }
 157
 158 int __init rd_load_image(char *from)
 159 {
 160         int res = 0;
 161         int in_fd, out_fd;
 162         unsigned long rd_blocks, devblocks;
 163         int nblocks, i, disk;
 164         char *buf = NULL;
 165         unsigned short rotate = 0;
 166         decompress_fn decompressor = NULL;
 167 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 168         char rotator[4] = { '|' , '/' , '-' , '\\' };
 169 #endif
 170
 171         out_fd = sys_open((const char __user __force *) "/dev/ram", O_RDWR, 0);
 172         if (out_fd < 0)
 173                 goto out;
 174
 175         in_fd = sys_open(from, O_RDONLY, 0);
 176         if (in_fd < 0)
 177                 goto noclose_input;
 178
 179         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 180         if (nblocks < 0)
 181                 goto done;
 182
 183         if (nblocks == 0) {
 184                 if (crd_load(in_fd, out_fd, decompressor) == 0)
 185                         goto successful_load;
 186                 goto done;
 187         }
 188
 189         /*
 190          * NOTE NOTE: nblocks is not actually blocks but
 191          * the number of kibibytes of data to load into a ramdisk.
 192          * So any ramdisk block size that is a multiple of 1KiB should
 193          * work when the appropriate ramdisk_blocksize is specified
 194          * on the command line.
 195          *
 196          * The default ramdisk_blocksize is 1KiB and it is generally
 197          * silly to use anything else, so make sure to use 1KiB
 198          * blocksize while generating ext2fs ramdisk-images.
 199          */
 200         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 201                 rd_blocks = 0;
 202         else
 203                 rd_blocks >>= 1;
 204
 205         if (nblocks > rd_blocks) {
 206                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 207                        nblocks, rd_blocks);
 208                 goto done;
 209         }
 210
 211         /*
 212          * OK, time to copy in the data
 213          */
 214         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 215                 devblocks = 0;
 216         else
 217                 devblocks >>= 1;
 218
 219         if (strcmp(from, "/initrd.image") == 0)
 220                 devblocks = nblocks;
 221
 222         if (devblocks == 0) {
 223                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 224                 goto done;
 225         }
 226
 227         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 228         if (!buf) {
 229                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 230                 goto done;
 231         }
 232
 233         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 234                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 235         for (i = 0, disk = 1; i < nblocks; i++) {
 236                 if (i && (i % devblocks == 0)) {
 237                         printk("done disk #%d.\n", disk++);
 238                         rotate = 0;
 239                         if (sys_close(in_fd)) {
 240                                 printk("Error closing the disk.\n");
 241                                 goto noclose_input;
 242                         }
 243                         change_floppy("disk #%d", disk);
 244                         in_fd = sys_open(from, O_RDONLY, 0);
 245                         if (in_fd < 0)  {
 246                                 printk("Error opening disk.\n");
 247                                 goto noclose_input;
 248                         }
 249                         printk("Loading disk #%d... ", disk);
 250                 }
 251                 sys_read(in_fd, buf, BLOCK_SIZE);
 252                 sys_write(out_fd, buf, BLOCK_SIZE);
 253 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 254                 if (!(i % 16)) {
 255                         printk("%c\b", rotator[rotate & 0x3]);
 256                         rotate++;
 257                 }
 258 #endif
 259         }
 260         printk("done.\n");
 261
 262 successful_load:
 263         res = 1;
 264 done:
 265         sys_close(in_fd);
 266 noclose_input:
 267         sys_close(out_fd);
 268 out:
 269         kfree(buf);
 270         sys_unlink((const char __user __force *) "/dev/ram");
 271         return res;
 272 }
 273
 274 int __init rd_load_disk(int n)
 275 {
 276         if (rd_prompt)
 277                 change_floppy("root floppy disk to be loaded into RAM disk");
 278         create_dev("/dev/root", ROOT_DEV);
 279         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 280         return rd_load_image("/dev/root");
 281 }
 282
 283 static int exit_code;
 284 static int decompress_error;
 285 static int crd_infd, crd_outfd;
 286
 287 static int __init compr_fill(void *buf, unsigned int len)
 288 {
 289         int r = sys_read(crd_infd, buf, len);
 290         if (r < 0)
 291                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 292         else if (r == 0)
 293                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 294         return r;
 295 }
 296
 297 static int __init compr_flush(void *window, unsigned int outcnt)
 298 {
 299         int written = sys_write(crd_outfd, window, outcnt);
 300         if (written != outcnt) {
 301                 if (decompress_error == 0)
 302                         printk(KERN_ERR
 303                                "RAMDISK: incomplete write (%d != %d)\n",
 304                                written, outcnt);
 305                 decompress_error = 1;
 306                 return -1;
 307         }
 308         return outcnt;
 309 }
 310
 311 static void __init error(char *x)
 312 {
 313         printk(KERN_ERR "%s\n", x);
 314         exit_code = 1;
 315         decompress_error = 1;
 316 }
 317
 318 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 319 {
 320         int result;
 321         crd_infd = in_fd;
 322         crd_outfd = out_fd;
 323         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 324         if (decompress_error)
 325                 result = 1;
 326         return result;
 327 }