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