init/initramfs.c

   1 #include <linux/init.h>
   2 #include <linux/fs.h>
   3 #include <linux/slab.h>
   4 #include <linux/types.h>
   5 #include <linux/fcntl.h>
   6 #include <linux/delay.h>
   7 #include <linux/string.h>
   8 #include <linux/syscalls.h>
   9
  10 static __initdata char *message;
  11 static void __init error(char *x)
  12 {
  13         if (!message)
  14                 message = x;
  15 }
  16
  17 static void __init *malloc(size_t size)
  18 {
  19         return kmalloc(size, GFP_KERNEL);
  20 }
  21
  22 static void __init free(void *where)
  23 {
  24         kfree(where);
  25 }
  26
  27 /* link hash */
  28
  29 static struct hash {
  30         int ino, minor, major;
  31         struct hash *next;
  32         char *name;
  33 } *head[32];
  34
  35 static inline int hash(int major, int minor, int ino)
  36 {
  37         unsigned long tmp = ino + minor + (major << 3);
  38         tmp += tmp >> 5;
  39         return tmp & 31;
  40 }
  41
  42 static char __init *find_link(int major, int minor, int ino, char *name)
  43 {
  44         struct hash **p, *q;
  45         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  46                 if ((*p)->ino != ino)
  47                         continue;
  48                 if ((*p)->minor != minor)
  49                         continue;
  50                 if ((*p)->major != major)
  51                         continue;
  52                 return (*p)->name;
  53         }
  54         q = (struct hash *)malloc(sizeof(struct hash));
  55         if (!q)
  56                 panic("can't allocate link hash entry");
  57         q->ino = ino;
  58         q->minor = minor;
  59         q->major = major;
  60         q->name = name;
  61         q->next = NULL;
  62         *p = q;
  63         return NULL;
  64 }
  65
  66 static void __init free_hash(void)
  67 {
  68         struct hash **p, *q;
  69         for (p = head; p < head + 32; p++) {
  70                 while (*p) {
  71                         q = *p;
  72                         *p = q->next;
  73                         free(q);
  74                 }
  75         }
  76 }
  77
  78 /* cpio header parsing */
  79
  80 static __initdata unsigned long ino, major, minor, nlink;
  81 static __initdata mode_t mode;
  82 static __initdata unsigned long body_len, name_len;
  83 static __initdata uid_t uid;
  84 static __initdata gid_t gid;
  85 static __initdata unsigned rdev;
  86
  87 static void __init parse_header(char *s)
  88 {
  89         unsigned long parsed[12];
  90         char buf[9];
  91         int i;
  92
  93         buf[8] = '\0';
  94         for (i = 0, s += 6; i < 12; i++, s += 8) {
  95                 memcpy(buf, s, 8);
  96                 parsed[i] = simple_strtoul(buf, NULL, 16);
  97         }
  98         ino = parsed[0];
  99         mode = parsed[1];
 100         uid = parsed[2];
 101         gid = parsed[3];
 102         nlink = parsed[4];
 103         body_len = parsed[6];
 104         major = parsed[7];
 105         minor = parsed[8];
 106         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 107         name_len = parsed[11];
 108 }
 109
 110 /* FSM */
 111
 112 static __initdata enum state {
 113         Start,
 114         Collect,
 115         GotHeader,
 116         SkipIt,
 117         GotName,
 118         CopyFile,
 119         GotSymlink,
 120         Reset
 121 } state, next_state;
 122
 123 static __initdata char *victim;
 124 static __initdata unsigned count;
 125 static __initdata loff_t this_header, next_header;
 126
 127 static __initdata int dry_run;
 128
 129 static inline void eat(unsigned n)
 130 {
 131         victim += n;
 132         this_header += n;
 133         count -= n;
 134 }
 135
 136 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
 137
 138 static __initdata char *collected;
 139 static __initdata int remains;
 140 static __initdata char *collect;
 141
 142 static void __init read_into(char *buf, unsigned size, enum state next)
 143 {
 144         if (count >= size) {
 145                 collected = victim;
 146                 eat(size);
 147                 state = next;
 148         } else {
 149                 collect = collected = buf;
 150                 remains = size;
 151                 next_state = next;
 152                 state = Collect;
 153         }
 154 }
 155
 156 static __initdata char *header_buf, *symlink_buf, *name_buf;
 157
 158 static int __init do_start(void)
 159 {
 160         read_into(header_buf, 110, GotHeader);
 161         return 0;
 162 }
 163
 164 static int __init do_collect(void)
 165 {
 166         unsigned n = remains;
 167         if (count < n)
 168                 n = count;
 169         memcpy(collect, victim, n);
 170         eat(n);
 171         collect += n;
 172         if (remains -= n)
 173                 return 1;
 174         state = next_state;
 175         return 0;
 176 }
 177
 178 static int __init do_header(void)
 179 {
 180         if (memcmp(collected, "070701", 6)) {
 181                 error("no cpio magic");
 182                 return 1;
 183         }
 184         parse_header(collected);
 185         next_header = this_header + N_ALIGN(name_len) + body_len;
 186         next_header = (next_header + 3) & ~3;
 187         if (dry_run) {
 188                 read_into(name_buf, N_ALIGN(name_len), GotName);
 189                 return 0;
 190         }
 191         state = SkipIt;
 192         if (name_len <= 0 || name_len > PATH_MAX)
 193                 return 0;
 194         if (S_ISLNK(mode)) {
 195                 if (body_len > PATH_MAX)
 196                         return 0;
 197                 collect = collected = symlink_buf;
 198                 remains = N_ALIGN(name_len) + body_len;
 199                 next_state = GotSymlink;
 200                 state = Collect;
 201                 return 0;
 202         }
 203         if (S_ISREG(mode) || !body_len)
 204                 read_into(name_buf, N_ALIGN(name_len), GotName);
 205         return 0;
 206 }
 207
 208 static int __init do_skip(void)
 209 {
 210         if (this_header + count <= next_header) {
 211                 eat(count);
 212                 return 1;
 213         } else {
 214                 eat(next_header - this_header);
 215                 state = next_state;
 216                 return 0;
 217         }
 218 }
 219
 220 static int __init do_reset(void)
 221 {
 222         while(count && *victim == '\0')
 223                 eat(1);
 224         if (count && (this_header & 3))
 225                 error("broken padding");
 226         return 1;
 227 }
 228
 229 static int __init maybe_link(void)
 230 {
 231         if (nlink >= 2) {
 232                 char *old = find_link(major, minor, ino, collected);
 233                 if (old)
 234                         return (sys_link(old, collected) < 0) ? -1 : 1;
 235         }
 236         return 0;
 237 }
 238
 239 static __initdata int wfd;
 240
 241 static int __init do_name(void)
 242 {
 243         state = SkipIt;
 244         next_state = Start;
 245         if (strcmp(collected, "TRAILER!!!") == 0) {
 246                 free_hash();
 247                 next_state = Reset;
 248                 return 0;
 249         }
 250         if (dry_run)
 251                 return 0;
 252         if (S_ISREG(mode)) {
 253                 if (maybe_link() >= 0) {
 254                         wfd = sys_open(collected, O_WRONLY|O_CREAT, mode);
 255                         if (wfd >= 0) {
 256                                 sys_fchown(wfd, uid, gid);
 257                                 sys_fchmod(wfd, mode);
 258                                 state = CopyFile;
 259                         }
 260                 }
 261         } else if (S_ISDIR(mode)) {
 262                 sys_mkdir(collected, mode);
 263                 sys_chown(collected, uid, gid);
 264                 sys_chmod(collected, mode);
 265         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 266                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 267                 if (maybe_link() == 0) {
 268                         sys_mknod(collected, mode, rdev);
 269                         sys_chown(collected, uid, gid);
 270                         sys_chmod(collected, mode);
 271                 }
 272         }
 273         return 0;
 274 }
 275
 276 static int __init do_copy(void)
 277 {
 278         if (count >= body_len) {
 279                 sys_write(wfd, victim, body_len);
 280                 sys_close(wfd);
 281                 eat(body_len);
 282                 state = SkipIt;
 283                 return 0;
 284         } else {
 285                 sys_write(wfd, victim, count);
 286                 body_len -= count;
 287                 eat(count);
 288                 return 1;
 289         }
 290 }
 291
 292 static int __init do_symlink(void)
 293 {
 294         collected[N_ALIGN(name_len) + body_len] = '\0';
 295         sys_symlink(collected + N_ALIGN(name_len), collected);
 296         sys_lchown(collected, uid, gid);
 297         state = SkipIt;
 298         next_state = Start;
 299         return 0;
 300 }
 301
 302 static __initdata int (*actions[])(void) = {
 303         [Start]         = do_start,
 304         [Collect]       = do_collect,
 305         [GotHeader]     = do_header,
 306         [SkipIt]        = do_skip,
 307         [GotName]       = do_name,
 308         [CopyFile]      = do_copy,
 309         [GotSymlink]    = do_symlink,
 310         [Reset]         = do_reset,
 311 };
 312
 313 static int __init write_buffer(char *buf, unsigned len)
 314 {
 315         count = len;
 316         victim = buf;
 317
 318         while (!actions[state]())
 319                 ;
 320         return len - count;
 321 }
 322
 323 static void __init flush_buffer(char *buf, unsigned len)
 324 {
 325         int written;
 326         if (message)
 327                 return;
 328         while ((written = write_buffer(buf, len)) < len && !message) {
 329                 char c = buf[written];
 330                 if (c == '0') {
 331                         buf += written;
 332                         len -= written;
 333                         state = Start;
 334                 } else
 335                         error("junk in compressed archive");
 336         }
 337 }
 338
 339 /*
 340  * gzip declarations
 341  */
 342
 343 #define OF(args)  args
 344
 345 #ifndef memzero
 346 #define memzero(s, n)     memset ((s), 0, (n))
 347 #endif
 348
 349 typedef unsigned char  uch;
 350 typedef unsigned short ush;
 351 typedef unsigned long  ulg;
 352
 353 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 354                         /*  at least 32K for zip's deflate method */
 355
 356 static uch *inbuf;
 357 static uch *window;
 358
 359 static unsigned insize;  /* valid bytes in inbuf */
 360 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 361 static unsigned outcnt;  /* bytes in output buffer */
 362 static long bytes_out;
 363
 364 #define get_byte()  (inptr < insize ? inbuf[inptr++] : -1)
 365
 366 /* Diagnostic functions (stubbed out) */
 367 #define Assert(cond,msg)
 368 #define Trace(x)
 369 #define Tracev(x)
 370 #define Tracevv(x)
 371 #define Tracec(c,x)
 372 #define Tracecv(c,x)
 373
 374 #define STATIC static
 375
 376 static void flush_window(void);
 377 static void error(char *m);
 378 static void gzip_mark(void **);
 379 static void gzip_release(void **);
 380
 381 #include "../lib/inflate.c"
 382
 383 static void __init gzip_mark(void **ptr)
 384 {
 385 }
 386
 387 static void __init gzip_release(void **ptr)
 388 {
 389 }
 390
 391 /* ===========================================================================
 392  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 393  * (Used for the decompressed data only.)
 394  */
 395 static void __init flush_window(void)
 396 {
 397         ulg c = crc;         /* temporary variable */
 398         unsigned n;
 399         uch *in, ch;
 400
 401         flush_buffer(window, outcnt);
 402         in = window;
 403         for (n = 0; n < outcnt; n++) {
 404                 ch = *in++;
 405                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 406         }
 407         crc = c;
 408         bytes_out += (ulg)outcnt;
 409         outcnt = 0;
 410 }
 411
 412 char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 413 {
 414         int written;
 415         dry_run = check_only;
 416         header_buf = malloc(110);
 417         symlink_buf = malloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1);
 418         name_buf = malloc(N_ALIGN(PATH_MAX));
 419         window = malloc(WSIZE);
 420         if (!window || !header_buf || !symlink_buf || !name_buf)
 421                 panic("can't allocate buffers");
 422         state = Start;
 423         this_header = 0;
 424         message = NULL;
 425         while (!message && len) {
 426                 loff_t saved_offset = this_header;
 427                 if (*buf == '0' && !(this_header & 3)) {
 428                         state = Start;
 429                         written = write_buffer(buf, len);
 430                         buf += written;
 431                         len -= written;
 432                         continue;
 433                 }
 434                 if (!*buf) {
 435                         buf++;
 436                         len--;
 437                         this_header++;
 438                         continue;
 439                 }
 440                 this_header = 0;
 441                 insize = len;
 442                 inbuf = buf;
 443                 inptr = 0;
 444                 outcnt = 0;             /* bytes in output buffer */
 445                 bytes_out = 0;
 446                 crc = (ulg)0xffffffffL; /* shift register contents */
 447                 makecrc();
 448                 if (gunzip())
 449                         message = "ungzip failed";
 450                 if (state != Reset)
 451                         error("junk in gzipped archive");
 452                 this_header = saved_offset + inptr;
 453                 buf += inptr;
 454                 len -= inptr;
 455         }
 456         free(window);
 457         free(name_buf);
 458         free(symlink_buf);
 459         free(header_buf);
 460         return message;
 461 }
 462
 463 extern char __initramfs_start, __initramfs_end;
 464 #ifdef CONFIG_BLK_DEV_INITRD
 465 #include <linux/initrd.h>
 466 #endif
 467
 468 void __init populate_rootfs(void)
 469 {
 470         char *err = unpack_to_rootfs(&__initramfs_start,
 471                          &__initramfs_end - &__initramfs_start, 0);
 472         if (err)
 473                 panic(err);
 474 #ifdef CONFIG_BLK_DEV_INITRD
 475         if (initrd_start) {
 476                 int fd;
 477                 printk(KERN_INFO "checking if image is initramfs...");
 478                 err = unpack_to_rootfs((char *)initrd_start,
 479                         initrd_end - initrd_start, 1);
 480                 if (!err) {
 481                         printk(" it is\n");
 482                         unpack_to_rootfs((char *)initrd_start,
 483                                 initrd_end - initrd_start, 0);
 484                         free_initrd_mem(initrd_start, initrd_end);
 485                         return;
 486                 }
 487                 printk("it isn't (%s); looks like an initrd\n", err);
 488                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 700);
 489                 if (fd >= 0) {
 490                         sys_write(fd, (char *)initrd_start,
 491                                         initrd_end - initrd_start);
 492                         sys_close(fd);
 493                         free_initrd_mem(initrd_start, initrd_end);
 494                 }
 495         }
 496 #endif
 497 }