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 = (struct hash *)malloc(sizeof(struct hash));
  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                         free(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 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, "070701", 6)) {
 186                 error("no cpio magic");
 187                 return 1;
 188         }
 189         parse_header(collected);
 190         next_header = this_header + N_ALIGN(name_len) + body_len;
 191         next_header = (next_header + 3) & ~3;
 192         if (dry_run) {
 193                 read_into(name_buf, N_ALIGN(name_len), GotName);
 194                 return 0;
 195         }
 196         state = SkipIt;
 197         if (name_len <= 0 || name_len > PATH_MAX)
 198                 return 0;
 199         if (S_ISLNK(mode)) {
 200                 if (body_len > PATH_MAX)
 201                         return 0;
 202                 collect = collected = symlink_buf;
 203                 remains = N_ALIGN(name_len) + body_len;
 204                 next_state = GotSymlink;
 205                 state = Collect;
 206                 return 0;
 207         }
 208         if (S_ISREG(mode) || !body_len)
 209                 read_into(name_buf, N_ALIGN(name_len), GotName);
 210         return 0;
 211 }
 212
 213 static int __init do_skip(void)
 214 {
 215         if (this_header + count < next_header) {
 216                 eat(count);
 217                 return 1;
 218         } else {
 219                 eat(next_header - this_header);
 220                 state = next_state;
 221                 return 0;
 222         }
 223 }
 224
 225 static int __init do_reset(void)
 226 {
 227         while(count && *victim == '\0')
 228                 eat(1);
 229         if (count && (this_header & 3))
 230                 error("broken padding");
 231         return 1;
 232 }
 233
 234 static int __init maybe_link(void)
 235 {
 236         if (nlink >= 2) {
 237                 char *old = find_link(major, minor, ino, mode, collected);
 238                 if (old)
 239                         return (sys_link(old, collected) < 0) ? -1 : 1;
 240         }
 241         return 0;
 242 }
 243
 244 static void __init clean_path(char *path, mode_t mode)
 245 {
 246         struct stat st;
 247
 248         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
 249                 if (S_ISDIR(st.st_mode))
 250                         sys_rmdir(path);
 251                 else
 252                         sys_unlink(path);
 253         }
 254 }
 255
 256 static __initdata int wfd;
 257
 258 static int __init do_name(void)
 259 {
 260         state = SkipIt;
 261         next_state = Reset;
 262         if (strcmp(collected, "TRAILER!!!") == 0) {
 263                 free_hash();
 264                 return 0;
 265         }
 266         if (dry_run)
 267                 return 0;
 268         clean_path(collected, mode);
 269         if (S_ISREG(mode)) {
 270                 int ml = maybe_link();
 271                 if (ml >= 0) {
 272                         int openflags = O_WRONLY|O_CREAT;
 273                         if (ml != 1)
 274                                 openflags |= O_TRUNC;
 275                         wfd = sys_open(collected, openflags, mode);
 276
 277                         if (wfd >= 0) {
 278                                 sys_fchown(wfd, uid, gid);
 279                                 sys_fchmod(wfd, mode);
 280                                 state = CopyFile;
 281                         }
 282                 }
 283         } else if (S_ISDIR(mode)) {
 284                 sys_mkdir(collected, mode);
 285                 sys_chown(collected, uid, gid);
 286                 sys_chmod(collected, mode);
 287         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 288                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 289                 if (maybe_link() == 0) {
 290                         sys_mknod(collected, mode, rdev);
 291                         sys_chown(collected, uid, gid);
 292                         sys_chmod(collected, mode);
 293                 }
 294         }
 295         return 0;
 296 }
 297
 298 static int __init do_copy(void)
 299 {
 300         if (count >= body_len) {
 301                 sys_write(wfd, victim, body_len);
 302                 sys_close(wfd);
 303                 eat(body_len);
 304                 state = SkipIt;
 305                 return 0;
 306         } else {
 307                 sys_write(wfd, victim, count);
 308                 body_len -= count;
 309                 eat(count);
 310                 return 1;
 311         }
 312 }
 313
 314 static int __init do_symlink(void)
 315 {
 316         collected[N_ALIGN(name_len) + body_len] = '\0';
 317         clean_path(collected, 0);
 318         sys_symlink(collected + N_ALIGN(name_len), collected);
 319         sys_lchown(collected, uid, gid);
 320         state = SkipIt;
 321         next_state = Reset;
 322         return 0;
 323 }
 324
 325 static __initdata int (*actions[])(void) = {
 326         [Start]         = do_start,
 327         [Collect]       = do_collect,
 328         [GotHeader]     = do_header,
 329         [SkipIt]        = do_skip,
 330         [GotName]       = do_name,
 331         [CopyFile]      = do_copy,
 332         [GotSymlink]    = do_symlink,
 333         [Reset]         = do_reset,
 334 };
 335
 336 static int __init write_buffer(char *buf, unsigned len)
 337 {
 338         count = len;
 339         victim = buf;
 340
 341         while (!actions[state]())
 342                 ;
 343         return len - count;
 344 }
 345
 346 static void __init flush_buffer(char *buf, unsigned len)
 347 {
 348         int written;
 349         if (message)
 350                 return;
 351         while ((written = write_buffer(buf, len)) < len && !message) {
 352                 char c = buf[written];
 353                 if (c == '0') {
 354                         buf += written;
 355                         len -= written;
 356                         state = Start;
 357                 } else if (c == 0) {
 358                         buf += written;
 359                         len -= written;
 360                         state = Reset;
 361                 } else
 362                         error("junk in compressed archive");
 363         }
 364 }
 365
 366 /*
 367  * gzip declarations
 368  */
 369
 370 #define OF(args)  args
 371
 372 #ifndef memzero
 373 #define memzero(s, n)     memset ((s), 0, (n))
 374 #endif
 375
 376 typedef unsigned char  uch;
 377 typedef unsigned short ush;
 378 typedef unsigned long  ulg;
 379
 380 #define WSIZE 0x8000    /* window size--must be a power of two, and */
 381                         /*  at least 32K for zip's deflate method */
 382
 383 static uch *inbuf;
 384 static uch *window;
 385
 386 static unsigned insize;  /* valid bytes in inbuf */
 387 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 388 static unsigned outcnt;  /* bytes in output buffer */
 389 static long bytes_out;
 390
 391 #define get_byte()  (inptr < insize ? inbuf[inptr++] : -1)
 392
 393 /* Diagnostic functions (stubbed out) */
 394 #define Assert(cond,msg)
 395 #define Trace(x)
 396 #define Tracev(x)
 397 #define Tracevv(x)
 398 #define Tracec(c,x)
 399 #define Tracecv(c,x)
 400
 401 #define STATIC static
 402 #define INIT __init
 403
 404 static void __init flush_window(void);
 405 static void __init error(char *m);
 406 static void __init gzip_mark(void **);
 407 static void __init gzip_release(void **);
 408
 409 #include "../lib/inflate.c"
 410
 411 static void __init gzip_mark(void **ptr)
 412 {
 413 }
 414
 415 static void __init gzip_release(void **ptr)
 416 {
 417 }
 418
 419 /* ===========================================================================
 420  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 421  * (Used for the decompressed data only.)
 422  */
 423 static void __init flush_window(void)
 424 {
 425         ulg c = crc;         /* temporary variable */
 426         unsigned n;
 427         uch *in, ch;
 428
 429         flush_buffer(window, outcnt);
 430         in = window;
 431         for (n = 0; n < outcnt; n++) {
 432                 ch = *in++;
 433                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 434         }
 435         crc = c;
 436         bytes_out += (ulg)outcnt;
 437         outcnt = 0;
 438 }
 439
 440 static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 441 {
 442         int written;
 443         dry_run = check_only;
 444         header_buf = malloc(110);
 445         symlink_buf = malloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1);
 446         name_buf = malloc(N_ALIGN(PATH_MAX));
 447         window = malloc(WSIZE);
 448         if (!window || !header_buf || !symlink_buf || !name_buf)
 449                 panic("can't allocate buffers");
 450         state = Start;
 451         this_header = 0;
 452         message = NULL;
 453         while (!message && len) {
 454                 loff_t saved_offset = this_header;
 455                 if (*buf == '0' && !(this_header & 3)) {
 456                         state = Start;
 457                         written = write_buffer(buf, len);
 458                         buf += written;
 459                         len -= written;
 460                         continue;
 461                 }
 462                 if (!*buf) {
 463                         buf++;
 464                         len--;
 465                         this_header++;
 466                         continue;
 467                 }
 468                 this_header = 0;
 469                 insize = len;
 470                 inbuf = buf;
 471                 inptr = 0;
 472                 outcnt = 0;             /* bytes in output buffer */
 473                 bytes_out = 0;
 474                 crc = (ulg)0xffffffffL; /* shift register contents */
 475                 makecrc();
 476                 gunzip();
 477                 if (state != Reset)
 478                         error("junk in gzipped archive");
 479                 this_header = saved_offset + inptr;
 480                 buf += inptr;
 481                 len -= inptr;
 482         }
 483         free(window);
 484         free(name_buf);
 485         free(symlink_buf);
 486         free(header_buf);
 487         return message;
 488 }
 489
 490 extern char __initramfs_start[], __initramfs_end[];
 491 #ifdef CONFIG_BLK_DEV_INITRD
 492 #include <linux/initrd.h>
 493 #include <linux/kexec.h>
 494
 495 static void __init free_initrd(void)
 496 {
 497 #ifdef CONFIG_KEXEC
 498         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 499         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 500
 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
 519         initrd_start = 0;
 520         initrd_end = 0;
 521 }
 522
 523 #endif
 524
 525 void __init populate_rootfs(void)
 526 {
 527         char *err = unpack_to_rootfs(__initramfs_start,
 528                          __initramfs_end - __initramfs_start, 0);
 529         if (err)
 530                 panic(err);
 531 #ifdef CONFIG_BLK_DEV_INITRD
 532         if (initrd_start) {
 533 #ifdef CONFIG_BLK_DEV_RAM
 534                 int fd;
 535                 printk(KERN_INFO "checking if image is initramfs...");
 536                 err = unpack_to_rootfs((char *)initrd_start,
 537                         initrd_end - initrd_start, 1);
 538                 if (!err) {
 539                         printk(" it is\n");
 540                         unpack_to_rootfs((char *)initrd_start,
 541                                 initrd_end - initrd_start, 0);
 542                         free_initrd();
 543                         return;
 544                 }
 545                 printk("it isn't (%s); looks like an initrd\n", err);
 546                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
 547                 if (fd >= 0) {
 548                         sys_write(fd, (char *)initrd_start,
 549                                         initrd_end - initrd_start);
 550                         sys_close(fd);
 551                         free_initrd();
 552                 }
 553 #else
 554                 printk(KERN_INFO "Unpacking initramfs...");
 555                 err = unpack_to_rootfs((char *)initrd_start,
 556                         initrd_end - initrd_start, 0);
 557                 if (err)
 558                         panic(err);
 559                 printk(" done\n");
 560                 free_initrd();
 561 #endif
 562         }
 563 #endif
 564 }