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 /* link hash */
  18
  19 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  20
  21 static __initdata struct hash {
  22         int ino, minor, major;
  23         mode_t mode;
  24         struct hash *next;
  25         char name[N_ALIGN(PATH_MAX)];
  26 } *head[32];
  27
  28 static inline int hash(int major, int minor, int ino)
  29 {
  30         unsigned long tmp = ino + minor + (major << 3);
  31         tmp += tmp >> 5;
  32         return tmp & 31;
  33 }
  34
  35 static char __init *find_link(int major, int minor, int ino,
  36                               mode_t mode, char *name)
  37 {
  38         struct hash **p, *q;
  39         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  40                 if ((*p)->ino != ino)
  41                         continue;
  42                 if ((*p)->minor != minor)
  43                         continue;
  44                 if ((*p)->major != major)
  45                         continue;
  46                 if (((*p)->mode ^ mode) & S_IFMT)
  47                         continue;
  48                 return (*p)->name;
  49         }
  50         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  51         if (!q)
  52                 panic("can't allocate link hash entry");
  53         q->major = major;
  54         q->minor = minor;
  55         q->ino = ino;
  56         q->mode = mode;
  57         strcpy(q->name, name);
  58         q->next = NULL;
  59         *p = q;
  60         return NULL;
  61 }
  62
  63 static void __init free_hash(void)
  64 {
  65         struct hash **p, *q;
  66         for (p = head; p < head + 32; p++) {
  67                 while (*p) {
  68                         q = *p;
  69                         *p = q->next;
  70                         kfree(q);
  71                 }
  72         }
  73 }
  74
  75 /* cpio header parsing */
  76
  77 static __initdata unsigned long ino, major, minor, nlink;
  78 static __initdata mode_t mode;
  79 static __initdata unsigned long body_len, name_len;
  80 static __initdata uid_t uid;
  81 static __initdata gid_t gid;
  82 static __initdata unsigned rdev;
  83
  84 static void __init parse_header(char *s)
  85 {
  86         unsigned long parsed[12];
  87         char buf[9];
  88         int i;
  89
  90         buf[8] = '\0';
  91         for (i = 0, s += 6; i < 12; i++, s += 8) {
  92                 memcpy(buf, s, 8);
  93                 parsed[i] = simple_strtoul(buf, NULL, 16);
  94         }
  95         ino = parsed[0];
  96         mode = parsed[1];
  97         uid = parsed[2];
  98         gid = parsed[3];
  99         nlink = parsed[4];
 100         body_len = parsed[6];
 101         major = parsed[7];
 102         minor = parsed[8];
 103         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 104         name_len = parsed[11];
 105 }
 106
 107 /* FSM */
 108
 109 static __initdata enum state {
 110         Start,
 111         Collect,
 112         GotHeader,
 113         SkipIt,
 114         GotName,
 115         CopyFile,
 116         GotSymlink,
 117         Reset
 118 } state, next_state;
 119
 120 static __initdata char *victim;
 121 static __initdata unsigned count;
 122 static __initdata loff_t this_header, next_header;
 123
 124 static __initdata int dry_run;
 125
 126 static inline void __init eat(unsigned n)
 127 {
 128         victim += n;
 129         this_header += n;
 130         count -= n;
 131 }
 132
 133 static __initdata char *collected;
 134 static __initdata int remains;
 135 static __initdata char *collect;
 136
 137 static void __init read_into(char *buf, unsigned size, enum state next)
 138 {
 139         if (count >= size) {
 140                 collected = victim;
 141                 eat(size);
 142                 state = next;
 143         } else {
 144                 collect = collected = buf;
 145                 remains = size;
 146                 next_state = next;
 147                 state = Collect;
 148         }
 149 }
 150
 151 static __initdata char *header_buf, *symlink_buf, *name_buf;
 152
 153 static int __init do_start(void)
 154 {
 155         read_into(header_buf, 110, GotHeader);
 156         return 0;
 157 }
 158
 159 static int __init do_collect(void)
 160 {
 161         unsigned n = remains;
 162         if (count < n)
 163                 n = count;
 164         memcpy(collect, victim, n);
 165         eat(n);
 166         collect += n;
 167         if ((remains -= n) != 0)
 168                 return 1;
 169         state = next_state;
 170         return 0;
 171 }
 172
 173 static int __init do_header(void)
 174 {
 175         if (memcmp(collected, "070707", 6)==0) {
 176                 error("incorrect cpio method used: use -H newc option");
 177                 return 1;
 178         }
 179         if (memcmp(collected, "070701", 6)) {
 180                 error("no cpio magic");
 181                 return 1;
 182         }
 183         parse_header(collected);
 184         next_header = this_header + N_ALIGN(name_len) + body_len;
 185         next_header = (next_header + 3) & ~3;
 186         if (dry_run) {
 187                 read_into(name_buf, N_ALIGN(name_len), GotName);
 188                 return 0;
 189         }
 190         state = SkipIt;
 191         if (name_len <= 0 || name_len > PATH_MAX)
 192                 return 0;
 193         if (S_ISLNK(mode)) {
 194                 if (body_len > PATH_MAX)
 195                         return 0;
 196                 collect = collected = symlink_buf;
 197                 remains = N_ALIGN(name_len) + body_len;
 198                 next_state = GotSymlink;
 199                 state = Collect;
 200                 return 0;
 201         }
 202         if (S_ISREG(mode) || !body_len)
 203                 read_into(name_buf, N_ALIGN(name_len), GotName);
 204         return 0;
 205 }
 206
 207 static int __init do_skip(void)
 208 {
 209         if (this_header + count < next_header) {
 210                 eat(count);
 211                 return 1;
 212         } else {
 213                 eat(next_header - this_header);
 214                 state = next_state;
 215                 return 0;
 216         }
 217 }
 218
 219 static int __init do_reset(void)
 220 {
 221         while(count && *victim == '\0')
 222                 eat(1);
 223         if (count && (this_header & 3))
 224                 error("broken padding");
 225         return 1;
 226 }
 227
 228 static int __init maybe_link(void)
 229 {
 230         if (nlink >= 2) {
 231                 char *old = find_link(major, minor, ino, mode, collected);
 232                 if (old)
 233                         return (sys_link(old, collected) < 0) ? -1 : 1;
 234         }
 235         return 0;
 236 }
 237
 238 static void __init clean_path(char *path, mode_t mode)
 239 {
 240         struct stat st;
 241
 242         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
 243                 if (S_ISDIR(st.st_mode))
 244                         sys_rmdir(path);
 245                 else
 246                         sys_unlink(path);
 247         }
 248 }
 249
 250 static __initdata int wfd;
 251
 252 static int __init do_name(void)
 253 {
 254         state = SkipIt;
 255         next_state = Reset;
 256         if (strcmp(collected, "TRAILER!!!") == 0) {
 257                 free_hash();
 258                 return 0;
 259         }
 260         if (dry_run)
 261                 return 0;
 262         clean_path(collected, mode);
 263         if (S_ISREG(mode)) {
 264                 int ml = maybe_link();
 265                 if (ml >= 0) {
 266                         int openflags = O_WRONLY|O_CREAT;
 267                         if (ml != 1)
 268                                 openflags |= O_TRUNC;
 269                         wfd = sys_open(collected, openflags, mode);
 270
 271                         if (wfd >= 0) {
 272                                 sys_fchown(wfd, uid, gid);
 273                                 sys_fchmod(wfd, mode);
 274                                 state = CopyFile;
 275                         }
 276                 }
 277         } else if (S_ISDIR(mode)) {
 278                 sys_mkdir(collected, mode);
 279                 sys_chown(collected, uid, gid);
 280                 sys_chmod(collected, mode);
 281         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 282                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 283                 if (maybe_link() == 0) {
 284                         sys_mknod(collected, mode, rdev);
 285                         sys_chown(collected, uid, gid);
 286                         sys_chmod(collected, mode);
 287                 }
 288         }
 289         return 0;
 290 }
 291
 292 static int __init do_copy(void)
 293 {
 294         if (count >= body_len) {
 295                 sys_write(wfd, victim, body_len);
 296                 sys_close(wfd);
 297                 eat(body_len);
 298                 state = SkipIt;
 299                 return 0;
 300         } else {
 301                 sys_write(wfd, victim, count);
 302                 body_len -= count;
 303                 eat(count);
 304                 return 1;
 305         }
 306 }
 307
 308 static int __init do_symlink(void)
 309 {
 310         collected[N_ALIGN(name_len) + body_len] = '\0';
 311         clean_path(collected, 0);
 312         sys_symlink(collected + N_ALIGN(name_len), collected);
 313         sys_lchown(collected, uid, gid);
 314         state = SkipIt;
 315         next_state = Reset;
 316         return 0;
 317 }
 318
 319 static __initdata int (*actions[])(void) = {
 320         [Start]         = do_start,
 321         [Collect]       = do_collect,
 322         [GotHeader]     = do_header,
 323         [SkipIt]        = do_skip,
 324         [GotName]       = do_name,
 325         [CopyFile]      = do_copy,
 326         [GotSymlink]    = do_symlink,
 327         [Reset]         = do_reset,
 328 };
 329
 330 static int __init write_buffer(char *buf, unsigned len)
 331 {
 332         count = len;
 333         victim = buf;
 334
 335         while (!actions[state]())
 336                 ;
 337         return len - count;
 338 }
 339
 340 static void __init flush_buffer(char *buf, unsigned len)
 341 {
 342         int written;
 343         if (message)
 344                 return;
 345         while ((written = write_buffer(buf, len)) < len && !message) {
 346                 char c = buf[written];
 347                 if (c == '0') {
 348                         buf += written;
 349                         len -= written;
 350                         state = Start;
 351                 } else if (c == 0) {
 352                         buf += written;
 353                         len -= written;
 354                         state = Reset;
 355                 } else
 356                         error("junk in compressed archive");
 357         }
 358 }
 359
 360 /*
 361  * gzip declarations
 362  */
 363
 364 #define OF(args)  args
 365
 366 #ifndef memzero
 367 #define memzero(s, n)     memset ((s), 0, (n))
 368 #endif
 369
 370 typedef unsigned char  uch;
 371 typedef unsigned short ush;
 372 typedef unsigned long  ulg;
 373
 374 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 375                         /*  at least 32K for zip's deflate method */
 376
 377 static uch *inbuf;
 378 static uch *window;
 379
 380 static unsigned insize;  /* valid bytes in inbuf */
 381 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 382 static unsigned outcnt;  /* bytes in output buffer */
 383 static long bytes_out;
 384
 385 #define get_byte()  (inptr < insize ? inbuf[inptr++] : -1)
 386
 387 /* Diagnostic functions (stubbed out) */
 388 #define Assert(cond,msg)
 389 #define Trace(x)
 390 #define Tracev(x)
 391 #define Tracevv(x)
 392 #define Tracec(c,x)
 393 #define Tracecv(c,x)
 394
 395 #define STATIC static
 396 #define INIT __init
 397
 398 static void __init flush_window(void);
 399 static void __init error(char *m);
 400
 401 #define NO_INFLATE_MALLOC
 402
 403 #include "../lib/inflate.c"
 404
 405 /* ===========================================================================
 406  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 407  * (Used for the decompressed data only.)
 408  */
 409 static void __init flush_window(void)
 410 {
 411         ulg c = crc;         /* temporary variable */
 412         unsigned n;
 413         uch *in, ch;
 414
 415         flush_buffer(window, outcnt);
 416         in = window;
 417         for (n = 0; n < outcnt; n++) {
 418                 ch = *in++;
 419                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 420         }
 421         crc = c;
 422         bytes_out += (ulg)outcnt;
 423         outcnt = 0;
 424 }
 425
 426 static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 427 {
 428         int written;
 429         dry_run = check_only;
 430         header_buf = kmalloc(110, GFP_KERNEL);
 431         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 432         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 433         window = kmalloc(WSIZE, GFP_KERNEL);
 434         if (!window || !header_buf || !symlink_buf || !name_buf)
 435                 panic("can't allocate buffers");
 436         state = Start;
 437         this_header = 0;
 438         message = NULL;
 439         while (!message && len) {
 440                 loff_t saved_offset = this_header;
 441                 if (*buf == '0' && !(this_header & 3)) {
 442                         state = Start;
 443                         written = write_buffer(buf, len);
 444                         buf += written;
 445                         len -= written;
 446                         continue;
 447                 }
 448                 if (!*buf) {
 449                         buf++;
 450                         len--;
 451                         this_header++;
 452                         continue;
 453                 }
 454                 this_header = 0;
 455                 insize = len;
 456                 inbuf = buf;
 457                 inptr = 0;
 458                 outcnt = 0;             /* bytes in output buffer */
 459                 bytes_out = 0;
 460                 crc = (ulg)0xffffffffL; /* shift register contents */
 461                 makecrc();
 462                 gunzip();
 463                 if (state != Reset)
 464                         error("junk in gzipped archive");
 465                 this_header = saved_offset + inptr;
 466                 buf += inptr;
 467                 len -= inptr;
 468         }
 469         kfree(window);
 470         kfree(name_buf);
 471         kfree(symlink_buf);
 472         kfree(header_buf);
 473         return message;
 474 }
 475
 476 static int __initdata do_retain_initrd;
 477
 478 static int __init retain_initrd_param(char *str)
 479 {
 480         if (*str)
 481                 return 0;
 482         do_retain_initrd = 1;
 483         return 1;
 484 }
 485 __setup("retain_initrd", retain_initrd_param);
 486
 487 extern char __initramfs_start[], __initramfs_end[];
 488 #include <linux/initrd.h>
 489 #include <linux/kexec.h>
 490
 491 static void __init free_initrd(void)
 492 {
 493 #ifdef CONFIG_KEXEC
 494         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 495         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 496 #endif
 497         if (do_retain_initrd)
 498                 goto skip;
 499
 500 #ifdef CONFIG_KEXEC
 501         /*
 502          * If the initrd region is overlapped with crashkernel reserved region,
 503          * free only memory that is not part of crashkernel region.
 504          */
 505         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 506                 /*
 507                  * Initialize initrd memory region since the kexec boot does
 508                  * not do.
 509                  */
 510                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 511                 if (initrd_start < crashk_start)
 512                         free_initrd_mem(initrd_start, crashk_start);
 513                 if (initrd_end > crashk_end)
 514                         free_initrd_mem(crashk_end, initrd_end);
 515         } else
 516 #endif
 517                 free_initrd_mem(initrd_start, initrd_end);
 518 skip:
 519         initrd_start = 0;
 520         initrd_end = 0;
 521 }
 522
 523 static int __init populate_rootfs(void)
 524 {
 525         char *err = unpack_to_rootfs(__initramfs_start,
 526                          __initramfs_end - __initramfs_start, 0);
 527         if (err)
 528                 panic(err);
 529         if (initrd_start) {
 530 #ifdef CONFIG_BLK_DEV_RAM
 531                 int fd;
 532                 printk(KERN_INFO "checking if image is initramfs...");
 533                 err = unpack_to_rootfs((char *)initrd_start,
 534                         initrd_end - initrd_start, 1);
 535                 if (!err) {
 536                         printk(" it is\n");
 537                         unpack_to_rootfs((char *)initrd_start,
 538                                 initrd_end - initrd_start, 0);
 539                         free_initrd();
 540                         return 0;
 541                 }
 542                 printk("it isn't (%s); looks like an initrd\n", err);
 543                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
 544                 if (fd >= 0) {
 545                         sys_write(fd, (char *)initrd_start,
 546                                         initrd_end - initrd_start);
 547                         sys_close(fd);
 548                         free_initrd();
 549                 }
 550 #else
 551                 printk(KERN_INFO "Unpacking initramfs...");
 552                 err = unpack_to_rootfs((char *)initrd_start,
 553                         initrd_end - initrd_start, 0);
 554                 if (err)
 555                         panic(err);
 556                 printk(" done\n");
 557                 free_initrd();
 558 #endif
 559         }
 560         return 0;
 561 }
 562 rootfs_initcall(populate_rootfs);