init/initramfs.c

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