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 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  30
  31 static __initdata struct hash {
  32         int ino, minor, major;
  33         mode_t mode;
  34         struct hash *next;
  35         char name[N_ALIGN(PATH_MAX)];
  36 } *head[32];
  37
  38 static inline int hash(int major, int minor, int ino)
  39 {
  40         unsigned long tmp = ino + minor + (major << 3);
  41         tmp += tmp >> 5;
  42         return tmp & 31;
  43 }
  44
  45 static char __init *find_link(int major, int minor, int ino,
  46                               mode_t mode, char *name)
  47 {
  48         struct hash **p, *q;
  49         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  50                 if ((*p)->ino != ino)
  51                         continue;
  52                 if ((*p)->minor != minor)
  53                         continue;
  54                 if ((*p)->major != major)
  55                         continue;
  56                 if (((*p)->mode ^ mode) & S_IFMT)
  57                         continue;
  58                 return (*p)->name;
  59         }
  60         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  61         if (!q)
  62                 panic("can't allocate link hash entry");
  63         q->major = major;
  64         q->minor = minor;
  65         q->ino = ino;
  66         q->mode = mode;
  67         strcpy(q->name, name);
  68         q->next = NULL;
  69         *p = q;
  70         return NULL;
  71 }
  72
  73 static void __init free_hash(void)
  74 {
  75         struct hash **p, *q;
  76         for (p = head; p < head + 32; p++) {
  77                 while (*p) {
  78                         q = *p;
  79                         *p = q->next;
  80                         kfree(q);
  81                 }
  82         }
  83 }
  84
  85 /* cpio header parsing */
  86
  87 static __initdata unsigned long ino, major, minor, nlink;
  88 static __initdata mode_t mode;
  89 static __initdata unsigned long body_len, name_len;
  90 static __initdata uid_t uid;
  91 static __initdata gid_t gid;
  92 static __initdata unsigned rdev;
  93
  94 static void __init parse_header(char *s)
  95 {
  96         unsigned long parsed[12];
  97         char buf[9];
  98         int i;
  99
 100         buf[8] = '\0';
 101         for (i = 0, s += 6; i < 12; i++, s += 8) {
 102                 memcpy(buf, s, 8);
 103                 parsed[i] = simple_strtoul(buf, NULL, 16);
 104         }
 105         ino = parsed[0];
 106         mode = parsed[1];
 107         uid = parsed[2];
 108         gid = parsed[3];
 109         nlink = parsed[4];
 110         body_len = parsed[6];
 111         major = parsed[7];
 112         minor = parsed[8];
 113         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 114         name_len = parsed[11];
 115 }
 116
 117 /* FSM */
 118
 119 static __initdata enum state {
 120         Start,
 121         Collect,
 122         GotHeader,
 123         SkipIt,
 124         GotName,
 125         CopyFile,
 126         GotSymlink,
 127         Reset
 128 } state, next_state;
 129
 130 static __initdata char *victim;
 131 static __initdata unsigned count;
 132 static __initdata loff_t this_header, next_header;
 133
 134 static __initdata int dry_run;
 135
 136 static inline void __init eat(unsigned n)
 137 {
 138         victim += n;
 139         this_header += n;
 140         count -= n;
 141 }
 142
 143 static __initdata char *collected;
 144 static __initdata int remains;
 145 static __initdata char *collect;
 146
 147 static void __init read_into(char *buf, unsigned size, enum state next)
 148 {
 149         if (count >= size) {
 150                 collected = victim;
 151                 eat(size);
 152                 state = next;
 153         } else {
 154                 collect = collected = buf;
 155                 remains = size;
 156                 next_state = next;
 157                 state = Collect;
 158         }
 159 }
 160
 161 static __initdata char *header_buf, *symlink_buf, *name_buf;
 162
 163 static int __init do_start(void)
 164 {
 165         read_into(header_buf, 110, GotHeader);
 166         return 0;
 167 }
 168
 169 static int __init do_collect(void)
 170 {
 171         unsigned n = remains;
 172         if (count < n)
 173                 n = count;
 174         memcpy(collect, victim, n);
 175         eat(n);
 176         collect += n;
 177         if ((remains -= n) != 0)
 178                 return 1;
 179         state = next_state;
 180         return 0;
 181 }
 182
 183 static int __init do_header(void)
 184 {
 185         if (memcmp(collected, "070707", 6)==0) {
 186                 error("incorrect cpio method used: use -H newc option");
 187                 return 1;
 188         }
 189         if (memcmp(collected, "070701", 6)) {
 190                 error("no cpio magic");
 191                 return 1;
 192         }
 193         parse_header(collected);
 194         next_header = this_header + N_ALIGN(name_len) + body_len;
 195         next_header = (next_header + 3) & ~3;
 196         if (dry_run) {
 197                 read_into(name_buf, N_ALIGN(name_len), GotName);
 198                 return 0;
 199         }
 200         state = SkipIt;
 201         if (name_len <= 0 || name_len > PATH_MAX)
 202                 return 0;
 203         if (S_ISLNK(mode)) {
 204                 if (body_len > PATH_MAX)
 205                         return 0;
 206                 collect = collected = symlink_buf;
 207                 remains = N_ALIGN(name_len) + body_len;
 208                 next_state = GotSymlink;
 209                 state = Collect;
 210                 return 0;
 211         }
 212         if (S_ISREG(mode) || !body_len)
 213                 read_into(name_buf, N_ALIGN(name_len), GotName);
 214         return 0;
 215 }
 216
 217 static int __init do_skip(void)
 218 {
 219         if (this_header + count < next_header) {
 220                 eat(count);
 221                 return 1;
 222         } else {
 223                 eat(next_header - this_header);
 224                 state = next_state;
 225                 return 0;
 226         }
 227 }
 228
 229 static int __init do_reset(void)
 230 {
 231         while(count && *victim == '\0')
 232                 eat(1);
 233         if (count && (this_header & 3))
 234                 error("broken padding");
 235         return 1;
 236 }
 237
 238 static int __init maybe_link(void)
 239 {
 240         if (nlink >= 2) {
 241                 char *old = find_link(major, minor, ino, mode, collected);
 242                 if (old)
 243                         return (sys_link(old, collected) < 0) ? -1 : 1;
 244         }
 245         return 0;
 246 }
 247
 248 static void __init clean_path(char *path, mode_t mode)
 249 {
 250         struct stat st;
 251
 252         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
 253                 if (S_ISDIR(st.st_mode))
 254                         sys_rmdir(path);
 255                 else
 256                         sys_unlink(path);
 257         }
 258 }
 259
 260 static __initdata int wfd;
 261
 262 static int __init do_name(void)
 263 {
 264         state = SkipIt;
 265         next_state = Reset;
 266         if (strcmp(collected, "TRAILER!!!") == 0) {
 267                 free_hash();
 268                 return 0;
 269         }
 270         if (dry_run)
 271                 return 0;
 272         clean_path(collected, mode);
 273         if (S_ISREG(mode)) {
 274                 int ml = maybe_link();
 275                 if (ml >= 0) {
 276                         int openflags = O_WRONLY|O_CREAT;
 277                         if (ml != 1)
 278                                 openflags |= O_TRUNC;
 279                         wfd = sys_open(collected, openflags, mode);
 280
 281                         if (wfd >= 0) {
 282                                 sys_fchown(wfd, uid, gid);
 283                                 sys_fchmod(wfd, mode);
 284                                 state = CopyFile;
 285                         }
 286                 }
 287         } else if (S_ISDIR(mode)) {
 288                 sys_mkdir(collected, mode);
 289                 sys_chown(collected, uid, gid);
 290                 sys_chmod(collected, mode);
 291         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 292                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 293                 if (maybe_link() == 0) {
 294                         sys_mknod(collected, mode, rdev);
 295                         sys_chown(collected, uid, gid);
 296                         sys_chmod(collected, mode);
 297                 }
 298         }
 299         return 0;
 300 }
 301
 302 static int __init do_copy(void)
 303 {
 304         if (count >= body_len) {
 305                 sys_write(wfd, victim, body_len);
 306                 sys_close(wfd);
 307                 eat(body_len);
 308                 state = SkipIt;
 309                 return 0;
 310         } else {
 311                 sys_write(wfd, victim, count);
 312                 body_len -= count;
 313                 eat(count);
 314                 return 1;
 315         }
 316 }
 317
 318 static int __init do_symlink(void)
 319 {
 320         collected[N_ALIGN(name_len) + body_len] = '\0';
 321         clean_path(collected, 0);
 322         sys_symlink(collected + N_ALIGN(name_len), collected);
 323         sys_lchown(collected, uid, gid);
 324         state = SkipIt;
 325         next_state = Reset;
 326         return 0;
 327 }
 328
 329 static __initdata int (*actions[])(void) = {
 330         [Start]         = do_start,
 331         [Collect]       = do_collect,
 332         [GotHeader]     = do_header,
 333         [SkipIt]        = do_skip,
 334         [GotName]       = do_name,
 335         [CopyFile]      = do_copy,
 336         [GotSymlink]    = do_symlink,
 337         [Reset]         = do_reset,
 338 };
 339
 340 static int __init write_buffer(char *buf, unsigned len)
 341 {
 342         count = len;
 343         victim = buf;
 344
 345         while (!actions[state]())
 346                 ;
 347         return len - count;
 348 }
 349
 350 static void __init flush_buffer(char *buf, unsigned len)
 351 {
 352         int written;
 353         if (message)
 354                 return;
 355         while ((written = write_buffer(buf, len)) < len && !message) {
 356                 char c = buf[written];
 357                 if (c == '0') {
 358                         buf += written;
 359                         len -= written;
 360                         state = Start;
 361                 } else if (c == 0) {
 362                         buf += written;
 363                         len -= written;
 364                         state = Reset;
 365                 } else
 366                         error("junk in compressed archive");
 367         }
 368 }
 369
 370 /*
 371  * gzip declarations
 372  */
 373
 374 #define OF(args)  args
 375
 376 #ifndef memzero
 377 #define memzero(s, n)     memset ((s), 0, (n))
 378 #endif
 379
 380 typedef unsigned char  uch;
 381 typedef unsigned short ush;
 382 typedef unsigned long  ulg;
 383
 384 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 385                         /*  at least 32K for zip's deflate method */
 386
 387 static uch *inbuf;
 388 static uch *window;
 389
 390 static unsigned insize;  /* valid bytes in inbuf */
 391 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 392 static unsigned outcnt;  /* bytes in output buffer */
 393 static long bytes_out;
 394
 395 #define get_byte()  (inptr < insize ? inbuf[inptr++] : -1)
 396
 397 /* Diagnostic functions (stubbed out) */
 398 #define Assert(cond,msg)
 399 #define Trace(x)
 400 #define Tracev(x)
 401 #define Tracevv(x)
 402 #define Tracec(c,x)
 403 #define Tracecv(c,x)
 404
 405 #define STATIC static
 406 #define INIT __init
 407
 408 static void __init flush_window(void);
 409 static void __init error(char *m);
 410 static void __init gzip_mark(void **);
 411 static void __init gzip_release(void **);
 412
 413 #include "../lib/inflate.c"
 414
 415 static void __init gzip_mark(void **ptr)
 416 {
 417 }
 418
 419 static void __init gzip_release(void **ptr)
 420 {
 421 }
 422
 423 /* ===========================================================================
 424  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 425  * (Used for the decompressed data only.)
 426  */
 427 static void __init flush_window(void)
 428 {
 429         ulg c = crc;         /* temporary variable */
 430         unsigned n;
 431         uch *in, ch;
 432
 433         flush_buffer(window, outcnt);
 434         in = window;
 435         for (n = 0; n < outcnt; n++) {
 436                 ch = *in++;
 437                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 438         }
 439         crc = c;
 440         bytes_out += (ulg)outcnt;
 441         outcnt = 0;
 442 }
 443
 444 static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 445 {
 446         int written;
 447         dry_run = check_only;
 448         header_buf = kmalloc(110, GFP_KERNEL);
 449         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 450         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 451         window = kmalloc(WSIZE, GFP_KERNEL);
 452         if (!window || !header_buf || !symlink_buf || !name_buf)
 453                 panic("can't allocate buffers");
 454         state = Start;
 455         this_header = 0;
 456         message = NULL;
 457         while (!message && len) {
 458                 loff_t saved_offset = this_header;
 459                 if (*buf == '0' && !(this_header & 3)) {
 460                         state = Start;
 461                         written = write_buffer(buf, len);
 462                         buf += written;
 463                         len -= written;
 464                         continue;
 465                 }
 466                 if (!*buf) {
 467                         buf++;
 468                         len--;
 469                         this_header++;
 470                         continue;
 471                 }
 472                 this_header = 0;
 473                 insize = len;
 474                 inbuf = buf;
 475                 inptr = 0;
 476                 outcnt = 0;             /* bytes in output buffer */
 477                 bytes_out = 0;
 478                 crc = (ulg)0xffffffffL; /* shift register contents */
 479                 makecrc();
 480                 gunzip();
 481                 if (state != Reset)
 482                         error("junk in gzipped archive");
 483                 this_header = saved_offset + inptr;
 484                 buf += inptr;
 485                 len -= inptr;
 486         }
 487         kfree(window);
 488         kfree(name_buf);
 489         kfree(symlink_buf);
 490         kfree(header_buf);
 491         return message;
 492 }
 493
 494 static int __initdata do_retain_initrd;
 495
 496 static int __init retain_initrd_param(char *str)
 497 {
 498         if (*str)
 499                 return 0;
 500         do_retain_initrd = 1;
 501         return 1;
 502 }
 503 __setup("retain_initrd", retain_initrd_param);
 504
 505 extern char __initramfs_start[], __initramfs_end[];
 506 #include <linux/initrd.h>
 507 #include <linux/kexec.h>
 508
 509 static void __init free_initrd(void)
 510 {
 511 #ifdef CONFIG_KEXEC
 512         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 513         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 514 #endif
 515         if (do_retain_initrd)
 516                 goto skip;
 517
 518 #ifdef CONFIG_KEXEC
 519         /*
 520          * If the initrd region is overlapped with crashkernel reserved region,
 521          * free only memory that is not part of crashkernel region.
 522          */
 523         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 524                 /*
 525                  * Initialize initrd memory region since the kexec boot does
 526                  * not do.
 527                  */
 528                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 529                 if (initrd_start < crashk_start)
 530                         free_initrd_mem(initrd_start, crashk_start);
 531                 if (initrd_end > crashk_end)
 532                         free_initrd_mem(crashk_end, initrd_end);
 533         } else
 534 #endif
 535                 free_initrd_mem(initrd_start, initrd_end);
 536 skip:
 537         initrd_start = 0;
 538         initrd_end = 0;
 539 }
 540
 541 static int __init populate_rootfs(void)
 542 {
 543         char *err = unpack_to_rootfs(__initramfs_start,
 544                          __initramfs_end - __initramfs_start, 0);
 545         if (err)
 546                 panic(err);
 547         if (initrd_start) {
 548 #ifdef CONFIG_BLK_DEV_RAM
 549                 int fd;
 550                 printk(KERN_INFO "checking if image is initramfs...");
 551                 err = unpack_to_rootfs((char *)initrd_start,
 552                         initrd_end - initrd_start, 1);
 553                 if (!err) {
 554                         printk(" it is\n");
 555                         unpack_to_rootfs((char *)initrd_start,
 556                                 initrd_end - initrd_start, 0);
 557                         free_initrd();
 558                         return 0;
 559                 }
 560                 printk("it isn't (%s); looks like an initrd\n", err);
 561                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
 562                 if (fd >= 0) {
 563                         sys_write(fd, (char *)initrd_start,
 564                                         initrd_end - initrd_start);
 565                         sys_close(fd);
 566                         free_initrd();
 567                 }
 568 #else
 569                 printk(KERN_INFO "Unpacking initramfs...");
 570                 err = unpack_to_rootfs((char *)initrd_start,
 571                         initrd_end - initrd_start, 0);
 572                 if (err)
 573                         panic(err);
 574                 printk(" done\n");
 575                 free_initrd();
 576 #endif
 577         }
 578         return 0;
 579 }
 580 rootfs_initcall(populate_rootfs);