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                 goto done;
 127         }
 128
 129         printk(KERN_NOTICE
 130                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 131                start_block);
 132
 133 done:
 134         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 135         kfree(buf);
 136         return nblocks;
 137 }
 138
 139 int __init rd_load_image(char *from)
 140 {
 141         int res = 0;
 142         int in_fd, out_fd;
 143         unsigned long rd_blocks, devblocks;
 144         int nblocks, i, disk;
 145         char *buf = NULL;
 146         unsigned short rotate = 0;
 147 #if !defined(CONFIG_ARCH_S390) && !defined(CONFIG_PPC_ISERIES)
 148         char rotator[4] = { '|' , '/' , '-' , '\\' };
 149 #endif
 150
 151         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 152         if (out_fd < 0)
 153                 goto out;
 154
 155         in_fd = sys_open(from, O_RDONLY, 0);
 156         if (in_fd < 0)
 157                 goto noclose_input;
 158
 159         nblocks = identify_ramdisk_image(in_fd, rd_image_start);
 160         if (nblocks < 0)
 161                 goto done;
 162
 163         if (nblocks == 0) {
 164 #ifdef BUILD_CRAMDISK
 165                 if (crd_load(in_fd, out_fd) == 0)
 166                         goto successful_load;
 167 #else
 168                 printk(KERN_NOTICE
 169                        "RAMDISK: Kernel does not support compressed "
 170                        "RAM disk images\n");
 171 #endif
 172                 goto done;
 173         }
 174
 175         /*
 176          * NOTE NOTE: nblocks suppose that the blocksize is BLOCK_SIZE, so
 177          * rd_load_image will work only with filesystem BLOCK_SIZE wide!
 178          * So make sure to use 1k blocksize while generating ext2fs
 179          * ramdisk-images.
 180          */
 181         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 182                 rd_blocks = 0;
 183         else
 184                 rd_blocks >>= 1;
 185
 186         if (nblocks > rd_blocks) {
 187                 printk("RAMDISK: image too big! (%d/%ld blocks)\n",
 188                        nblocks, rd_blocks);
 189                 goto done;
 190         }
 191
 192         /*
 193          * OK, time to copy in the data
 194          */
 195         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 196                 devblocks = 0;
 197         else
 198                 devblocks >>= 1;
 199
 200         if (strcmp(from, "/initrd.image") == 0)
 201                 devblocks = nblocks;
 202
 203         if (devblocks == 0) {
 204                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 205                 goto done;
 206         }
 207
 208         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 209         if (buf == 0) {
 210                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 211                 goto done;
 212         }
 213
 214         printk(KERN_NOTICE "RAMDISK: Loading %d blocks [%ld disk%s] into ram disk... ",
 215                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 216         for (i = 0, disk = 1; i < nblocks; i++) {
 217                 if (i && (i % devblocks == 0)) {
 218                         printk("done disk #%d.\n", disk++);
 219                         rotate = 0;
 220                         if (sys_close(in_fd)) {
 221                                 printk("Error closing the disk.\n");
 222                                 goto noclose_input;
 223                         }
 224                         change_floppy("disk #%d", disk);
 225                         in_fd = sys_open(from, O_RDONLY, 0);
 226                         if (in_fd < 0)  {
 227                                 printk("Error opening disk.\n");
 228                                 goto noclose_input;
 229                         }
 230                         printk("Loading disk #%d... ", disk);
 231                 }
 232                 sys_read(in_fd, buf, BLOCK_SIZE);
 233                 sys_write(out_fd, buf, BLOCK_SIZE);
 234 #if !defined(CONFIG_ARCH_S390) && !defined(CONFIG_PPC_ISERIES)
 235                 if (!(i % 16)) {
 236                         printk("%c\b", rotator[rotate & 0x3]);
 237                         rotate++;
 238                 }
 239 #endif
 240         }
 241         printk("done.\n");
 242
 243 successful_load:
 244         res = 1;
 245 done:
 246         sys_close(in_fd);
 247 noclose_input:
 248         sys_close(out_fd);
 249 out:
 250         kfree(buf);
 251         sys_unlink("/dev/ram");
 252         return res;
 253 }
 254
 255 int __init rd_load_disk(int n)
 256 {
 257         if (rd_prompt)
 258                 change_floppy("root floppy disk to be loaded into RAM disk");
 259         create_dev("/dev/root", ROOT_DEV, root_device_name);
 260         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n), NULL);
 261         return rd_load_image("/dev/root");
 262 }
 263
 264 #ifdef BUILD_CRAMDISK
 265
 266 /*
 267  * gzip declarations
 268  */
 269
 270 #define OF(args)  args
 271
 272 #ifndef memzero
 273 #define memzero(s, n)     memset ((s), 0, (n))
 274 #endif
 275
 276 typedef unsigned char  uch;
 277 typedef unsigned short ush;
 278 typedef unsigned long  ulg;
 279
 280 #define INBUFSIZ 4096
 281 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 282                         /*  at least 32K for zip's deflate method */
 283
 284 static uch *inbuf;
 285 static uch *window;
 286
 287 static unsigned insize;  /* valid bytes in inbuf */
 288 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 289 static unsigned outcnt;  /* bytes in output buffer */
 290 static int exit_code;
 291 static int unzip_error;
 292 static long bytes_out;
 293 static int crd_infd, crd_outfd;
 294
 295 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 296
 297 /* Diagnostic functions (stubbed out) */
 298 #define Assert(cond,msg)
 299 #define Trace(x)
 300 #define Tracev(x)
 301 #define Tracevv(x)
 302 #define Tracec(c,x)
 303 #define Tracecv(c,x)
 304
 305 #define STATIC static
 306
 307 static int  fill_inbuf(void);
 308 static void flush_window(void);
 309 static void *malloc(int size);
 310 static void free(void *where);
 311 static void error(char *m);
 312 static void gzip_mark(void **);
 313 static void gzip_release(void **);
 314
 315 #include "../lib/inflate.c"
 316
 317 static void __init *malloc(int size)
 318 {
 319         return kmalloc(size, GFP_KERNEL);
 320 }
 321
 322 static void __init free(void *where)
 323 {
 324         kfree(where);
 325 }
 326
 327 static void __init gzip_mark(void **ptr)
 328 {
 329 }
 330
 331 static void __init gzip_release(void **ptr)
 332 {
 333 }
 334
 335
 336 /* ===========================================================================
 337  * Fill the input buffer. This is called only when the buffer is empty
 338  * and at least one byte is really needed.
 339  * Returning -1 does not guarantee that gunzip() will ever return.
 340  */
 341 static int __init fill_inbuf(void)
 342 {
 343         if (exit_code) return -1;
 344
 345         insize = sys_read(crd_infd, inbuf, INBUFSIZ);
 346         if (insize == 0) {
 347                 error("RAMDISK: ran out of compressed data");
 348                 return -1;
 349         }
 350
 351         inptr = 1;
 352
 353         return inbuf[0];
 354 }
 355
 356 /* ===========================================================================
 357  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 358  * (Used for the decompressed data only.)
 359  */
 360 static void __init flush_window(void)
 361 {
 362     ulg c = crc;         /* temporary variable */
 363     unsigned n, written;
 364     uch *in, ch;
 365
 366     written = sys_write(crd_outfd, window, outcnt);
 367     if (written != outcnt && unzip_error == 0) {
 368         printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
 369                written, outcnt, bytes_out);
 370         unzip_error = 1;
 371     }
 372     in = window;
 373     for (n = 0; n < outcnt; n++) {
 374             ch = *in++;
 375             c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 376     }
 377     crc = c;
 378     bytes_out += (ulg)outcnt;
 379     outcnt = 0;
 380 }
 381
 382 static void __init error(char *x)
 383 {
 384         printk(KERN_ERR "%s\n", x);
 385         exit_code = 1;
 386         unzip_error = 1;
 387 }
 388
 389 static int __init crd_load(int in_fd, int out_fd)
 390 {
 391         int result;
 392
 393         insize = 0;             /* valid bytes in inbuf */
 394         inptr = 0;              /* index of next byte to be processed in inbuf */
 395         outcnt = 0;             /* bytes in output buffer */
 396         exit_code = 0;
 397         bytes_out = 0;
 398         crc = (ulg)0xffffffffL; /* shift register contents */
 399
 400         crd_infd = in_fd;
 401         crd_outfd = out_fd;
 402         inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);
 403         if (inbuf == 0) {
 404                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");
 405                 return -1;
 406         }
 407         window = kmalloc(WSIZE, GFP_KERNEL);
 408         if (window == 0) {
 409                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
 410                 kfree(inbuf);
 411                 return -1;
 412         }
 413         makecrc();
 414         result = gunzip();
 415         if (unzip_error)
 416                 result = 1;
 417         kfree(inbuf);
 418         kfree(window);
 419         return result;
 420 }
 421
 422 #endif  /* BUILD_CRAMDISK */