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 #include "../fs/squashfs/squashfs_fs.h"
  13
  14 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  15
  16 static int __init prompt_ramdisk(char *str)
  17 {
  18         rd_prompt = simple_strtol(str,NULL,0) & 1;
  19         return 1;
  20 }
  21 __setup("prompt_ramdisk=", prompt_ramdisk);
  22
  23 int __initdata rd_image_start;          /* starting block # of image */
  24
  25 static int __init ramdisk_start_setup(char *str)
  26 {
  27         rd_image_start = simple_strtol(str,NULL,0);
  28         return 1;
  29 }
  30 __setup("ramdisk_start=", ramdisk_start_setup);
  31
  32 static int __init crd_load(int in_fd, int out_fd);
  33
  34 /*
  35  * This routine tries to find a RAM disk image to load, and returns the
  36  * number of blocks to read for a non-compressed image, 0 if the image
  37  * is a compressed image, and -1 if an image with the right magic
  38  * numbers could not be found.
  39  *
  40  * We currently check for the following magic numbers:
  41  *      minix
  42  *      ext2
  43  *      romfs
  44  *      cramfs
  45  *      squashfs
  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         struct squashfs_super_block *squashfsb;
  57         int nblocks = -1;
  58         unsigned char *buf;
  59
  60         buf = kmalloc(size, GFP_KERNEL);
  61         if (!buf)
  62                 return -1;
  63
  64         minixsb = (struct minix_super_block *) buf;
  65         ext2sb = (struct ext2_super_block *) buf;
  66         romfsb = (struct romfs_super_block *) buf;
  67         cramfsb = (struct cramfs_super *) buf;
  68         squashfsb = (struct squashfs_super_block *) buf;
  69         memset(buf, 0xe5, size);
  70
  71         /*
  72          * Read block 0 to test for gzipped kernel
  73          */
  74         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  75         sys_read(fd, buf, size);
  76
  77         /*
  78          * If it matches the gzip magic numbers, return 0
  79          */
  80         if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
  81                 printk(KERN_NOTICE
  82                        "RAMDISK: Compressed image found at block %d\n",
  83                        start_block);
  84                 nblocks = 0;
  85                 goto done;
  86         }
  87
  88         /* romfs is at block zero too */
  89         if (romfsb->word0 == ROMSB_WORD0 &&
  90             romfsb->word1 == ROMSB_WORD1) {
  91                 printk(KERN_NOTICE
  92                        "RAMDISK: romfs filesystem found at block %d\n",
  93                        start_block);
  94                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
  95                 goto done;
  96         }
  97
  98         if (cramfsb->magic == CRAMFS_MAGIC) {
  99                 printk(KERN_NOTICE
 100                        "RAMDISK: cramfs filesystem found at block %d\n",
 101                        start_block);
 102                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 103                 goto done;
 104         }
 105
 106         /* squashfs is at block zero too */
 107         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 108                 printk(KERN_NOTICE
 109                        "RAMDISK: squashfs filesystem found at block %d\n",
 110                        start_block);
 111                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 112                          >> BLOCK_SIZE_BITS;
 113                 goto done;
 114         }
 115
 116         /*
 117          * Read block 1 to test for minix and ext2 superblock
 118          */
 119         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 120         sys_read(fd, buf, size);
 121
 122         /* Try minix */
 123         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 124             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 125                 printk(KERN_NOTICE
 126                        "RAMDISK: Minix filesystem found at block %d\n",
 127                        start_block);
 128                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 129                 goto done;
 130         }
 131
 132         /* Try ext2 */
 133         if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
 134                 printk(KERN_NOTICE
 135                        "RAMDISK: ext2 filesystem found at block %d\n",
 136                        start_block);
 137                 nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
 138                         le32_to_cpu(ext2sb->s_log_block_size);
 139                 goto done;
 140         }
 141
 142         printk(KERN_NOTICE
 143                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 144                start_block);
 145
 146 done:
 147         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 148         kfree(buf);
 149         return nblocks;
 150 }
 151
 152 int __init rd_load_image(char *from)
 153 {
 154         int res = 0;
 155         int in_fd, out_fd;
 156         unsigned long rd_blocks, devblocks;
 157         int nblocks, i, disk;
 158         char *buf = NULL;
 159         unsigned short rotate = 0;
 160 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 161         char rotator[4] = { '|' , '/' , '-' , '\\' };
 162 #endif
 163
 164         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 165         if (out_fd < 0)
 166                 goto out;
 167
 168         in_fd = sys_open(from, O_RDONLY, 0);
 169         if (in_fd < 0)
 170                 goto noclose_input;
 171
 172         nblocks = identify_ramdisk_image(in_fd, rd_image_start);
 173         if (nblocks < 0)
 174                 goto done;
 175
 176         if (nblocks == 0) {
 177                 if (crd_load(in_fd, out_fd) == 0)
 178                         goto successful_load;
 179                 goto done;
 180         }
 181
 182         /*
 183          * NOTE NOTE: nblocks is not actually blocks but
 184          * the number of kibibytes of data to load into a ramdisk.
 185          * So any ramdisk block size that is a multiple of 1KiB should
 186          * work when the appropriate ramdisk_blocksize is specified
 187          * on the command line.
 188          *
 189          * The default ramdisk_blocksize is 1KiB and it is generally
 190          * silly to use anything else, so make sure to use 1KiB
 191          * blocksize while generating ext2fs ramdisk-images.
 192          */
 193         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 194                 rd_blocks = 0;
 195         else
 196                 rd_blocks >>= 1;
 197
 198         if (nblocks > rd_blocks) {
 199                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 200                        nblocks, rd_blocks);
 201                 goto done;
 202         }
 203
 204         /*
 205          * OK, time to copy in the data
 206          */
 207         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 208                 devblocks = 0;
 209         else
 210                 devblocks >>= 1;
 211
 212         if (strcmp(from, "/initrd.image") == 0)
 213                 devblocks = nblocks;
 214
 215         if (devblocks == 0) {
 216                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 217                 goto done;
 218         }
 219
 220         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 221         if (!buf) {
 222                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 223                 goto done;
 224         }
 225
 226         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 227                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 228         for (i = 0, disk = 1; i < nblocks; i++) {
 229                 if (i && (i % devblocks == 0)) {
 230                         printk("done disk #%d.\n", disk++);
 231                         rotate = 0;
 232                         if (sys_close(in_fd)) {
 233                                 printk("Error closing the disk.\n");
 234                                 goto noclose_input;
 235                         }
 236                         change_floppy("disk #%d", disk);
 237                         in_fd = sys_open(from, O_RDONLY, 0);
 238                         if (in_fd < 0)  {
 239                                 printk("Error opening disk.\n");
 240                                 goto noclose_input;
 241                         }
 242                         printk("Loading disk #%d... ", disk);
 243                 }
 244                 sys_read(in_fd, buf, BLOCK_SIZE);
 245                 sys_write(out_fd, buf, BLOCK_SIZE);
 246 #if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
 247                 if (!(i % 16)) {
 248                         printk("%c\b", rotator[rotate & 0x3]);
 249                         rotate++;
 250                 }
 251 #endif
 252         }
 253         printk("done.\n");
 254
 255 successful_load:
 256         res = 1;
 257 done:
 258         sys_close(in_fd);
 259 noclose_input:
 260         sys_close(out_fd);
 261 out:
 262         kfree(buf);
 263         sys_unlink("/dev/ram");
 264         return res;
 265 }
 266
 267 int __init rd_load_disk(int n)
 268 {
 269         if (rd_prompt)
 270                 change_floppy("root floppy disk to be loaded into RAM disk");
 271         create_dev("/dev/root", ROOT_DEV);
 272         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 273         return rd_load_image("/dev/root");
 274 }
 275
 276 /*
 277  * gzip declarations
 278  */
 279
 280 #define OF(args)  args
 281
 282 #ifndef memzero
 283 #define memzero(s, n)     memset ((s), 0, (n))
 284 #endif
 285
 286 typedef unsigned char  uch;
 287 typedef unsigned short ush;
 288 typedef unsigned long  ulg;
 289
 290 #define INBUFSIZ 4096
 291 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 292                         /*  at least 32K for zip's deflate method */
 293
 294 static uch *inbuf;
 295 static uch *window;
 296
 297 static unsigned insize;  /* valid bytes in inbuf */
 298 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 299 static unsigned outcnt;  /* bytes in output buffer */
 300 static int exit_code;
 301 static int unzip_error;
 302 static long bytes_out;
 303 static int crd_infd, crd_outfd;
 304
 305 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 306
 307 /* Diagnostic functions (stubbed out) */
 308 #define Assert(cond,msg)
 309 #define Trace(x)
 310 #define Tracev(x)
 311 #define Tracevv(x)
 312 #define Tracec(c,x)
 313 #define Tracecv(c,x)
 314
 315 #define STATIC static
 316 #define INIT __init
 317
 318 static int  __init fill_inbuf(void);
 319 static void __init flush_window(void);
 320 static void __init error(char *m);
 321
 322 #define NO_INFLATE_MALLOC
 323
 324 #include "../lib/inflate.c"
 325
 326 /* ===========================================================================
 327  * Fill the input buffer. This is called only when the buffer is empty
 328  * and at least one byte is really needed.
 329  * Returning -1 does not guarantee that gunzip() will ever return.
 330  */
 331 static int __init fill_inbuf(void)
 332 {
 333         if (exit_code) return -1;
 334
 335         insize = sys_read(crd_infd, inbuf, INBUFSIZ);
 336         if (insize == 0) {
 337                 error("RAMDISK: ran out of compressed data");
 338                 return -1;
 339         }
 340
 341         inptr = 1;
 342
 343         return inbuf[0];
 344 }
 345
 346 /* ===========================================================================
 347  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 348  * (Used for the decompressed data only.)
 349  */
 350 static void __init flush_window(void)
 351 {
 352     ulg c = crc;         /* temporary variable */
 353     unsigned n, written;
 354     uch *in, ch;
 355
 356     written = sys_write(crd_outfd, window, outcnt);
 357     if (written != outcnt && unzip_error == 0) {
 358         printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
 359                written, outcnt, bytes_out);
 360         unzip_error = 1;
 361     }
 362     in = window;
 363     for (n = 0; n < outcnt; n++) {
 364             ch = *in++;
 365             c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 366     }
 367     crc = c;
 368     bytes_out += (ulg)outcnt;
 369     outcnt = 0;
 370 }
 371
 372 static void __init error(char *x)
 373 {
 374         printk(KERN_ERR "%s\n", x);
 375         exit_code = 1;
 376         unzip_error = 1;
 377 }
 378
 379 static int __init crd_load(int in_fd, int out_fd)
 380 {
 381         int result;
 382
 383         insize = 0;             /* valid bytes in inbuf */
 384         inptr = 0;              /* index of next byte to be processed in inbuf */
 385         outcnt = 0;             /* bytes in output buffer */
 386         exit_code = 0;
 387         bytes_out = 0;
 388         crc = (ulg)0xffffffffL; /* shift register contents */
 389
 390         crd_infd = in_fd;
 391         crd_outfd = out_fd;
 392         inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);
 393         if (!inbuf) {
 394                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");
 395                 return -1;
 396         }
 397         window = kmalloc(WSIZE, GFP_KERNEL);
 398         if (!window) {
 399                 printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
 400                 kfree(inbuf);
 401                 return -1;
 402         }
 403         makecrc();
 404         result = gunzip();
 405         if (unzip_error)
 406                 result = 1;
 407         kfree(inbuf);
 408         kfree(window);
 409         return result;
 410 }