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/squashfs_fs.h>
   9 #include <linux/initrd.h>
  10 #include <linux/string.h>
  11
  12 #include "do_mounts.h"
  13
  14 #define BUILD_CRAMDISK
  15
  16 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  17
  18 static int __init prompt_ramdisk(char *str)
  19 {
  20         rd_prompt = simple_strtol(str,NULL,0) & 1;
  21         return 1;
  22 }
  23 __setup("prompt_ramdisk=", prompt_ramdisk);
  24
  25 int __initdata rd_image_start;          /* starting block # of image */
  26
  27 static int __init ramdisk_start_setup(char *str)
  28 {
  29         rd_image_start = simple_strtol(str,NULL,0);
  30         return 1;
  31 }
  32 __setup("ramdisk_start=", ramdisk_start_setup);
  33
  34 static int __init crd_load(int in_fd, int out_fd);
  35
  36 /*
  37  * This routine tries to find a RAM disk image to load, and returns the
  38  * number of blocks to read for a non-compressed image, 0 if the image
  39  * is a compressed image, and -1 if an image with the right magic
  40  * numbers could not be found.
  41  *
  42  * We currently check for the following magic numbers:
  43  *      squashfs
  44  *      minix
  45  *      ext2
  46  *      romfs
  47  *      cramfs
  48  *      gzip
  49  */
  50 static int __init
  51 identify_ramdisk_image(int fd, int start_block)
  52 {
  53         const int size = 512;
  54         struct minix_super_block *minixsb;
  55         struct ext2_super_block *ext2sb;
  56         struct romfs_super_block *romfsb;
  57         struct cramfs_super *cramfsb;
  58         struct squashfs_super_block *squashfsb;
  59         int nblocks = -1;
  60         unsigned char *buf;
  61
  62         buf = kmalloc(size, GFP_KERNEL);
  63         if (buf == 0)
  64                 return -1;
  65
  66         minixsb = (struct minix_super_block *) buf;
  67         ext2sb = (struct ext2_super_block *) buf;
  68         romfsb = (struct romfs_super_block *) buf;
  69         cramfsb = (struct cramfs_super *) buf;
  70         squashfsb = (struct squashfs_super_block *) buf;
  71         memset(buf, 0xe5, size);
  72
  73         /*
  74          * Read block 0 to test for gzipped kernel
  75          */
  76         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  77         sys_read(fd, buf, size);
  78
  79         /*
  80          * If it matches the gzip magic numbers, return -1
  81          */
  82         if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
  83                 printk(KERN_NOTICE
  84                        "RAMDISK: Compressed image found at block %d\n",
  85                        start_block);
  86                 nblocks = 0;
  87                 goto done;
  88         }
  89
  90         /* romfs is at block zero too */
  91         if (romfsb->word0 == ROMSB_WORD0 &&
  92             romfsb->word1 == ROMSB_WORD1) {
  93                 printk(KERN_NOTICE
  94                        "RAMDISK: romfs filesystem found at block %d\n",
  95                        start_block);
  96                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
  97                 goto done;
  98         }
  99
 100         if (cramfsb->magic == le32_to_cpu(CRAMFS_MAGIC)) {
 101                 printk(KERN_NOTICE
 102                        "RAMDISK: cramfs filesystem found at block %d\n",
 103                        start_block);
 104                 nblocks = (le32_to_cpu(cramfsb->size) + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 105                 goto done;
 106         }
 107
 108         /* squashfs is at block zero too */
 109         if (squashfsb->s_magic == SQUASHFS_MAGIC) {
 110                 printk(KERN_NOTICE
 111                        "RAMDISK: squashfs filesystem found at block %d\n",
 112                        start_block);
 113                 nblocks = (squashfsb->bytes_used+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 114                 goto done;
 115         }
 116
 117         /*
 118          * Read block 1 to test for minix and ext2 superblock
 119          */
 120         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 121         sys_read(fd, buf, size);
 122
 123         /* Try minix */
 124         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 125             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 126                 printk(KERN_NOTICE
 127                        "RAMDISK: Minix filesystem found at block %d\n",
 128                        start_block);
 129                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 130                 goto done;
 131         }
 132
 133         /* Try ext2 */
 134         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 135                 printk(KERN_NOTICE
 136                        "RAMDISK: ext2 filesystem found at block %d\n",
 137                        start_block);
 138                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 139                         le32_to_cpu(ext2sb->s_log_block_size);
 140                 goto done;
 141         }
 142
 143         printk(KERN_NOTICE
 144                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 145                start_block);
 146
 147 done:
 148         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 149         kfree(buf);
 150         return nblocks;
 151 }
 152
 153 int __init rd_load_image(char *from)
 154 {
 155         int res = 0;
 156         int in_fd, out_fd;
 157         unsigned long rd_blocks, devblocks;
 158         int nblocks, i, disk;
 159         char *buf = NULL;
 160         unsigned short rotate = 0;
 161 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 162         char rotator[4] = { '|' , '/' , '-' , '\\' };
 163 #endif
 164
 165         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 166         if (out_fd < 0)
 167                 goto out;
 168
 169         in_fd = sys_open(from, O_RDONLY, 0);
 170         if (in_fd < 0)
 171                 goto noclose_input;
 172
 173         nblocks = identify_ramdisk_image(in_fd, rd_image_start);
 174         if (nblocks < 0)
 175                 goto done;
 176
 177         if (nblocks == 0) {
 178 #ifdef BUILD_CRAMDISK
 179                 if (crd_load(in_fd, out_fd) == 0)
 180                         goto successful_load;
 181 #else
 182                 printk(KERN_NOTICE
 183                        "RAMDISK: Kernel does not support compressed "
 184                        "RAM disk images\n");
 185 #endif
 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 == 0) {
 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("/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 #ifdef BUILD_CRAMDISK
 284
 285 /*
 286  * gzip declarations
 287  */
 288
 289 #define OF(args)  args
 290
 291 #ifndef memzero
 292 #define memzero(s, n)     memset ((s), 0, (n))
 293 #endif
 294
 295 typedef unsigned char  uch;
 296 typedef unsigned short ush;
 297 typedef unsigned long  ulg;
 298
 299 #define INBUFSIZ 4096
 300 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 301                         /*  at least 32K for zip's deflate method */
 302
 303 static uch *inbuf;
 304 static uch *window;
 305
 306 static unsigned insize;  /* valid bytes in inbuf */
 307 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 308 static unsigned outcnt;  /* bytes in output buffer */
 309 static int exit_code;
 310 static int unzip_error;
 311 static long bytes_out;
 312 static int crd_infd, crd_outfd;
 313
 314 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 315
 316 /* Diagnostic functions (stubbed out) */
 317 #define Assert(cond,msg)
 318 #define Trace(x)
 319 #define Tracev(x)
 320 #define Tracevv(x)
 321 #define Tracec(c,x)
 322 #define Tracecv(c,x)
 323
 324 #define STATIC static
 325 #define INIT __init
 326
 327 static int  __init fill_inbuf(void);
 328 static void __init flush_window(void);
 329 static void __init *malloc(size_t size);
 330 static void __init free(void *where);
 331 static void __init error(char *m);
 332 static void __init gzip_mark(void **);
 333 static void __init gzip_release(void **);
 334
 335 #include "../lib/inflate.c"
 336
 337 static void __init *malloc(size_t size)
 338 {
 339         return kmalloc(size, GFP_KERNEL);
 340 }
 341
 342 static void __init free(void *where)
 343 {
 344         kfree(where);
 345 }
 346
 347 static void __init gzip_mark(void **ptr)
 348 {
 349 }
 350
 351 static void __init gzip_release(void **ptr)
 352 {
 353 }
 354
 355
 356 /* ===========================================================================
 357  * Fill the input buffer. This is called only when the buffer is empty
 358  * and at least one byte is really needed.
 359  * Returning -1 does not guarantee that gunzip() will ever return.
 360  */
 361 static int __init fill_inbuf(void)
 362 {
 363         if (exit_code) return -1;
 364
 365         insize = sys_read(crd_infd, inbuf, INBUFSIZ);
 366         if (insize == 0) {
 367                 error("RAMDISK: ran out of compressed data");
 368                 return -1;
 369         }
 370
 371         inptr = 1;
 372
 373         return inbuf[0];
 374 }
 375
 376 /* ===========================================================================
 377  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 378  * (Used for the decompressed data only.)
 379  */
 380 static void __init flush_window(void)
 381 {
 382     ulg c = crc;         /* temporary variable */
 383     unsigned n, written;
 384     uch *in, ch;
 385
 386     written = sys_write(crd_outfd, window, outcnt);
 387     if (written != outcnt && unzip_error == 0) {
 388         printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
 389                written, outcnt, bytes_out);
 390         unzip_error = 1;
 391     }
 392     in = window;
 393     for (n = 0; n < outcnt; n++) {
 394             ch = *in++;
 395             c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 396     }
 397     crc = c;
 398     bytes_out += (ulg)outcnt;
 399     outcnt = 0;
 400 }
 401
 402 static void __init error(char *x)
 403 {
 404         printk(KERN_ERR "%s\n", x);
 405         exit_code = 1;
 406         unzip_error = 1;
 407 }
 408
 409 static int __init crd_load(int in_fd, int out_fd)
 410 {
 411         int result;
 412
 413         insize = 0;             /* valid bytes in inbuf */
 414         inptr = 0;              /* index of next byte to be processed in inbuf */
 415         outcnt = 0;             /* bytes in output buffer */
 416         exit_code = 0;
 417         bytes_out = 0;
 418         crc = (ulg)0xffffffffL; /* shift register contents */
 419
 420         crd_infd = in_fd;
 421         crd_outfd = out_fd;
 422         inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);
 423         if (inbuf == 0) {
 424                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");
 425                 return -1;
 426         }
 427         window = kmalloc(WSIZE, GFP_KERNEL);
 428         if (window == 0) {
 429                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
 430                 kfree(inbuf);
 431                 return -1;
 432         }
 433         makecrc();
 434         result = gunzip();
 435         if (unzip_error)
 436                 result = 1;
 437         kfree(inbuf);
 438         kfree(window);
 439         return result;
 440 }
 441
 442 #endif  /* BUILD_CRAMDISK */