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
  11 #include "do_mounts.h"
  12
  13 #define BUILD_CRAMDISK
  14
  15 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  16
  17 static int __init prompt_ramdisk(char *str)
  18 {
  19         rd_prompt = simple_strtol(str,NULL,0) & 1;
  20         return 1;
  21 }
  22 __setup("prompt_ramdisk=", prompt_ramdisk);
  23
  24 int __initdata rd_image_start;          /* starting block # of image */
  25
  26 static int __init ramdisk_start_setup(char *str)
  27 {
  28         rd_image_start = simple_strtol(str,NULL,0);
  29         return 1;
  30 }
  31 __setup("ramdisk_start=", ramdisk_start_setup);
  32
  33 static int __init crd_load(int in_fd, int out_fd);
  34
  35 /*
  36  * This routine tries to find a RAM disk image to load, and returns the
  37  * number of blocks to read for a non-compressed image, 0 if the image
  38  * is a compressed image, and -1 if an image with the right magic
  39  * numbers could not be found.
  40  *
  41  * We currently check for the following magic numbers:
  42  *      minix
  43  *      ext2
  44  *      romfs
  45  *      cramfs
  46  *      gzip
  47  */
  48 static int __init
  49 identify_ramdisk_image(int fd, int start_block)
  50 {
  51         const int size = 512;
  52         struct minix_super_block *minixsb;
  53         struct ext2_super_block *ext2sb;
  54         struct romfs_super_block *romfsb;
  55         struct cramfs_super *cramfsb;
  56         int nblocks = -1;
  57         unsigned char *buf;
  58
  59         buf = kmalloc(size, GFP_KERNEL);
  60         if (buf == 0)
  61                 return -1;
  62
  63         minixsb = (struct minix_super_block *) buf;
  64         ext2sb = (struct ext2_super_block *) buf;
  65         romfsb = (struct romfs_super_block *) buf;
  66         cramfsb = (struct cramfs_super *) buf;
  67         memset(buf, 0xe5, size);
  68
  69         /*
  70          * Read block 0 to test for gzipped kernel
  71          */
  72         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  73         sys_read(fd, buf, size);
  74
  75         /*
  76          * If it matches the gzip magic numbers, return -1
  77          */
  78         if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
  79                 printk(KERN_NOTICE
  80                        "RAMDISK: Compressed image found at block %d\n",
  81                        start_block);
  82                 nblocks = 0;
  83                 goto done;
  84         }
  85
  86         /* romfs is at block zero too */
  87         if (romfsb->word0 == ROMSB_WORD0 &&
  88             romfsb->word1 == ROMSB_WORD1) {
  89                 printk(KERN_NOTICE
  90                        "RAMDISK: romfs filesystem found at block %d\n",
  91                        start_block);
  92                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
  93                 goto done;
  94         }
  95
  96         if (cramfsb->magic == CRAMFS_MAGIC) {
  97                 printk(KERN_NOTICE
  98                        "RAMDISK: cramfs filesystem found at block %d\n",
  99                        start_block);
 100                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 101                 goto done;
 102         }
 103
 104         /*
 105          * Read block 1 to test for minix and ext2 superblock
 106          */
 107         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 108         sys_read(fd, buf, size);
 109
 110         /* Try minix */
 111         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 112             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 113                 printk(KERN_NOTICE
 114                        "RAMDISK: Minix filesystem found at block %d\n",
 115                        start_block);
 116                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 117                 goto done;
 118         }
 119
 120         /* Try ext2 */
 121         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 122                 printk(KERN_NOTICE
 123                        "RAMDISK: ext2 filesystem found at block %d\n",
 124                        start_block);
 125                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 126                         le32_to_cpu(ext2sb->s_log_block_size);
 127                 goto done;
 128         }
 129
 130         printk(KERN_NOTICE
 131                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 132                start_block);
 133
 134 done:
 135         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 136         kfree(buf);
 137         return nblocks;
 138 }
 139
 140 int __init rd_load_image(char *from)
 141 {
 142         int res = 0;
 143         int in_fd, out_fd;
 144         unsigned long rd_blocks, devblocks;
 145         int nblocks, i, disk;
 146         char *buf = NULL;
 147         unsigned short rotate = 0;
 148 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 149         char rotator[4] = { '|' , '/' , '-' , '\\' };
 150 #endif
 151
 152         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 153         if (out_fd < 0)
 154                 goto out;
 155
 156         in_fd = sys_open(from, O_RDONLY, 0);
 157         if (in_fd < 0)
 158                 goto noclose_input;
 159
 160         nblocks = identify_ramdisk_image(in_fd, rd_image_start);
 161         if (nblocks < 0)
 162                 goto done;
 163
 164         if (nblocks == 0) {
 165 #ifdef BUILD_CRAMDISK
 166                 if (crd_load(in_fd, out_fd) == 0)
 167                         goto successful_load;
 168 #else
 169                 printk(KERN_NOTICE
 170                        "RAMDISK: Kernel does not support compressed "
 171                        "RAM disk images\n");
 172 #endif
 173                 goto done;
 174         }
 175
 176         /*
 177          * NOTE NOTE: nblocks is not actually blocks but
 178          * the number of kibibytes of data to load into a ramdisk.
 179          * So any ramdisk block size that is a multiple of 1KiB should
 180          * work when the appropriate ramdisk_blocksize is specified
 181          * on the command line.
 182          *
 183          * The default ramdisk_blocksize is 1KiB and it is generally
 184          * silly to use anything else, so make sure to use 1KiB
 185          * blocksize while generating ext2fs ramdisk-images.
 186          */
 187         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 188                 rd_blocks = 0;
 189         else
 190                 rd_blocks >>= 1;
 191
 192         if (nblocks > rd_blocks) {
 193                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 194                        nblocks, rd_blocks);
 195                 goto done;
 196         }
 197
 198         /*
 199          * OK, time to copy in the data
 200          */
 201         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 202                 devblocks = 0;
 203         else
 204                 devblocks >>= 1;
 205
 206         if (strcmp(from, "/initrd.image") == 0)
 207                 devblocks = nblocks;
 208
 209         if (devblocks == 0) {
 210                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 211                 goto done;
 212         }
 213
 214         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 215         if (buf == 0) {
 216                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 217                 goto done;
 218         }
 219
 220         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 221                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 222         for (i = 0, disk = 1; i < nblocks; i++) {
 223                 if (i && (i % devblocks == 0)) {
 224                         printk("done disk #%d.\n", disk++);
 225                         rotate = 0;
 226                         if (sys_close(in_fd)) {
 227                                 printk("Error closing the disk.\n");
 228                                 goto noclose_input;
 229                         }
 230                         change_floppy("disk #%d", disk);
 231                         in_fd = sys_open(from, O_RDONLY, 0);
 232                         if (in_fd < 0)  {
 233                                 printk("Error opening disk.\n");
 234                                 goto noclose_input;
 235                         }
 236                         printk("Loading disk #%d... ", disk);
 237                 }
 238                 sys_read(in_fd, buf, BLOCK_SIZE);
 239                 sys_write(out_fd, buf, BLOCK_SIZE);
 240 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 241                 if (!(i % 16)) {
 242                         printk("%c\b", rotator[rotate & 0x3]);
 243                         rotate++;
 244                 }
 245 #endif
 246         }
 247         printk("done.\n");
 248
 249 successful_load:
 250         res = 1;
 251 done:
 252         sys_close(in_fd);
 253 noclose_input:
 254         sys_close(out_fd);
 255 out:
 256         kfree(buf);
 257         sys_unlink("/dev/ram");
 258         return res;
 259 }
 260
 261 int __init rd_load_disk(int n)
 262 {
 263         if (rd_prompt)
 264                 change_floppy("root floppy disk to be loaded into RAM disk");
 265         create_dev("/dev/root", ROOT_DEV);
 266         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 267         return rd_load_image("/dev/root");
 268 }
 269
 270 #ifdef BUILD_CRAMDISK
 271
 272 /*
 273  * gzip declarations
 274  */
 275
 276 #define OF(args)  args
 277
 278 #ifndef memzero
 279 #define memzero(s, n)     memset ((s), 0, (n))
 280 #endif
 281
 282 typedef unsigned char  uch;
 283 typedef unsigned short ush;
 284 typedef unsigned long  ulg;
 285
 286 #define INBUFSIZ 4096
 287 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 288                         /*  at least 32K for zip's deflate method */
 289
 290 static uch *inbuf;
 291 static uch *window;
 292
 293 static unsigned insize;  /* valid bytes in inbuf */
 294 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 295 static unsigned outcnt;  /* bytes in output buffer */
 296 static int exit_code;
 297 static int unzip_error;
 298 static long bytes_out;
 299 static int crd_infd, crd_outfd;
 300
 301 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 302
 303 /* Diagnostic functions (stubbed out) */
 304 #define Assert(cond,msg)
 305 #define Trace(x)
 306 #define Tracev(x)
 307 #define Tracevv(x)
 308 #define Tracec(c,x)
 309 #define Tracecv(c,x)
 310
 311 #define STATIC static
 312 #define INIT __init
 313
 314 static int  __init fill_inbuf(void);
 315 static void __init flush_window(void);
 316 static void __init *malloc(size_t size);
 317 static void __init free(void *where);
 318 static void __init error(char *m);
 319 static void __init gzip_mark(void **);
 320 static void __init gzip_release(void **);
 321
 322 #include "../lib/inflate.c"
 323
 324 static void __init *malloc(size_t size)
 325 {
 326         return kmalloc(size, GFP_KERNEL);
 327 }
 328
 329 static void __init free(void *where)
 330 {
 331         kfree(where);
 332 }
 333
 334 static void __init gzip_mark(void **ptr)
 335 {
 336 }
 337
 338 static void __init gzip_release(void **ptr)
 339 {
 340 }
 341
 342
 343 /* ===========================================================================
 344  * Fill the input buffer. This is called only when the buffer is empty
 345  * and at least one byte is really needed.
 346  * Returning -1 does not guarantee that gunzip() will ever return.
 347  */
 348 static int __init fill_inbuf(void)
 349 {
 350         if (exit_code) return -1;
 351
 352         insize = sys_read(crd_infd, inbuf, INBUFSIZ);
 353         if (insize == 0) {
 354                 error("RAMDISK: ran out of compressed data");
 355                 return -1;
 356         }
 357
 358         inptr = 1;
 359
 360         return inbuf[0];
 361 }
 362
 363 /* ===========================================================================
 364  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 365  * (Used for the decompressed data only.)
 366  */
 367 static void __init flush_window(void)
 368 {
 369     ulg c = crc;         /* temporary variable */
 370     unsigned n, written;
 371     uch *in, ch;
 372
 373     written = sys_write(crd_outfd, window, outcnt);
 374     if (written != outcnt && unzip_error == 0) {
 375         printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
 376                written, outcnt, bytes_out);
 377         unzip_error = 1;
 378     }
 379     in = window;
 380     for (n = 0; n < outcnt; n++) {
 381             ch = *in++;
 382             c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 383     }
 384     crc = c;
 385     bytes_out += (ulg)outcnt;
 386     outcnt = 0;
 387 }
 388
 389 static void __init error(char *x)
 390 {
 391         printk(KERN_ERR "%s\n", x);
 392         exit_code = 1;
 393         unzip_error = 1;
 394 }
 395
 396 static int __init crd_load(int in_fd, int out_fd)
 397 {
 398         int result;
 399
 400         insize = 0;             /* valid bytes in inbuf */
 401         inptr = 0;              /* index of next byte to be processed in inbuf */
 402         outcnt = 0;             /* bytes in output buffer */
 403         exit_code = 0;
 404         bytes_out = 0;
 405         crc = (ulg)0xffffffffL; /* shift register contents */
 406
 407         crd_infd = in_fd;
 408         crd_outfd = out_fd;
 409         inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);
 410         if (inbuf == 0) {
 411                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");
 412                 return -1;
 413         }
 414         window = kmalloc(WSIZE, GFP_KERNEL);
 415         if (window == 0) {
 416                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
 417                 kfree(inbuf);
 418                 return -1;
 419         }
 420         makecrc();
 421         result = gunzip();
 422         if (unzip_error)
 423                 result = 1;
 424         kfree(inbuf);
 425         kfree(window);
 426         return result;
 427 }
 428
 429 #endif  /* BUILD_CRAMDISK */