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/dirent.h>
   9 #include <linux/syscalls.h>
  10 #include <linux/utime.h>
  11
  12 static __initdata char *message;
  13 static void __init error(char *x)
  14 {
  15         if (!message)
  16                 message = x;
  17 }
  18
  19 /* link hash */
  20
  21 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  22
  23 static __initdata struct hash {
  24         int ino, minor, major;
  25         mode_t mode;
  26         struct hash *next;
  27         char name[N_ALIGN(PATH_MAX)];
  28 } *head[32];
  29
  30 static inline int hash(int major, int minor, int ino)
  31 {
  32         unsigned long tmp = ino + minor + (major << 3);
  33         tmp += tmp >> 5;
  34         return tmp & 31;
  35 }
  36
  37 static char __init *find_link(int major, int minor, int ino,
  38                               mode_t mode, char *name)
  39 {
  40         struct hash **p, *q;
  41         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  42                 if ((*p)->ino != ino)
  43                         continue;
  44                 if ((*p)->minor != minor)
  45                         continue;
  46                 if ((*p)->major != major)
  47                         continue;
  48                 if (((*p)->mode ^ mode) & S_IFMT)
  49                         continue;
  50                 return (*p)->name;
  51         }
  52         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  53         if (!q)
  54                 panic("can't allocate link hash entry");
  55         q->major = major;
  56         q->minor = minor;
  57         q->ino = ino;
  58         q->mode = mode;
  59         strcpy(q->name, name);
  60         q->next = NULL;
  61         *p = q;
  62         return NULL;
  63 }
  64
  65 static void __init free_hash(void)
  66 {
  67         struct hash **p, *q;
  68         for (p = head; p < head + 32; p++) {
  69                 while (*p) {
  70                         q = *p;
  71                         *p = q->next;
  72                         kfree(q);
  73                 }
  74         }
  75 }
  76
  77 static long __init do_utime(char __user *filename, time_t mtime)
  78 {
  79         struct timespec t[2];
  80
  81         t[0].tv_sec = mtime;
  82         t[0].tv_nsec = 0;
  83         t[1].tv_sec = mtime;
  84         t[1].tv_nsec = 0;
  85
  86         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
  87 }
  88
  89 static __initdata LIST_HEAD(dir_list);
  90 struct dir_entry {
  91         struct list_head list;
  92         char *name;
  93         time_t mtime;
  94 };
  95
  96 static void __init dir_add(const char *name, time_t mtime)
  97 {
  98         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
  99         if (!de)
 100                 panic("can't allocate dir_entry buffer");
 101         INIT_LIST_HEAD(&de->list);
 102         de->name = kstrdup(name, GFP_KERNEL);
 103         de->mtime = mtime;
 104         list_add(&de->list, &dir_list);
 105 }
 106
 107 static void __init dir_utime(void)
 108 {
 109         struct dir_entry *de, *tmp;
 110         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 111                 list_del(&de->list);
 112                 do_utime(de->name, de->mtime);
 113                 kfree(de->name);
 114                 kfree(de);
 115         }
 116 }
 117
 118 static __initdata time_t mtime;
 119
 120 /* cpio header parsing */
 121
 122 static __initdata unsigned long ino, major, minor, nlink;
 123 static __initdata mode_t mode;
 124 static __initdata unsigned long body_len, name_len;
 125 static __initdata uid_t uid;
 126 static __initdata gid_t gid;
 127 static __initdata unsigned rdev;
 128
 129 static void __init parse_header(char *s)
 130 {
 131         unsigned long parsed[12];
 132         char buf[9];
 133         int i;
 134
 135         buf[8] = '\0';
 136         for (i = 0, s += 6; i < 12; i++, s += 8) {
 137                 memcpy(buf, s, 8);
 138                 parsed[i] = simple_strtoul(buf, NULL, 16);
 139         }
 140         ino = parsed[0];
 141         mode = parsed[1];
 142         uid = parsed[2];
 143         gid = parsed[3];
 144         nlink = parsed[4];
 145         mtime = parsed[5];
 146         body_len = parsed[6];
 147         major = parsed[7];
 148         minor = parsed[8];
 149         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 150         name_len = parsed[11];
 151 }
 152
 153 /* FSM */
 154
 155 static __initdata enum state {
 156         Start,
 157         Collect,
 158         GotHeader,
 159         SkipIt,
 160         GotName,
 161         CopyFile,
 162         GotSymlink,
 163         Reset
 164 } state, next_state;
 165
 166 static __initdata char *victim;
 167 static __initdata unsigned count;
 168 static __initdata loff_t this_header, next_header;
 169
 170 static inline void __init eat(unsigned n)
 171 {
 172         victim += n;
 173         this_header += n;
 174         count -= n;
 175 }
 176
 177 static __initdata char *vcollected;
 178 static __initdata char *collected;
 179 static __initdata int remains;
 180 static __initdata char *collect;
 181
 182 static void __init read_into(char *buf, unsigned size, enum state next)
 183 {
 184         if (count >= size) {
 185                 collected = victim;
 186                 eat(size);
 187                 state = next;
 188         } else {
 189                 collect = collected = buf;
 190                 remains = size;
 191                 next_state = next;
 192                 state = Collect;
 193         }
 194 }
 195
 196 static __initdata char *header_buf, *symlink_buf, *name_buf;
 197
 198 static int __init do_start(void)
 199 {
 200         read_into(header_buf, 110, GotHeader);
 201         return 0;
 202 }
 203
 204 static int __init do_collect(void)
 205 {
 206         unsigned n = remains;
 207         if (count < n)
 208                 n = count;
 209         memcpy(collect, victim, n);
 210         eat(n);
 211         collect += n;
 212         if ((remains -= n) != 0)
 213                 return 1;
 214         state = next_state;
 215         return 0;
 216 }
 217
 218 static int __init do_header(void)
 219 {
 220         if (memcmp(collected, "070707", 6)==0) {
 221                 error("incorrect cpio method used: use -H newc option");
 222                 return 1;
 223         }
 224         if (memcmp(collected, "070701", 6)) {
 225                 error("no cpio magic");
 226                 return 1;
 227         }
 228         parse_header(collected);
 229         next_header = this_header + N_ALIGN(name_len) + body_len;
 230         next_header = (next_header + 3) & ~3;
 231         state = SkipIt;
 232         if (name_len <= 0 || name_len > PATH_MAX)
 233                 return 0;
 234         if (S_ISLNK(mode)) {
 235                 if (body_len > PATH_MAX)
 236                         return 0;
 237                 collect = collected = symlink_buf;
 238                 remains = N_ALIGN(name_len) + body_len;
 239                 next_state = GotSymlink;
 240                 state = Collect;
 241                 return 0;
 242         }
 243         if (S_ISREG(mode) || !body_len)
 244                 read_into(name_buf, N_ALIGN(name_len), GotName);
 245         return 0;
 246 }
 247
 248 static int __init do_skip(void)
 249 {
 250         if (this_header + count < next_header) {
 251                 eat(count);
 252                 return 1;
 253         } else {
 254                 eat(next_header - this_header);
 255                 state = next_state;
 256                 return 0;
 257         }
 258 }
 259
 260 static int __init do_reset(void)
 261 {
 262         while(count && *victim == '\0')
 263                 eat(1);
 264         if (count && (this_header & 3))
 265                 error("broken padding");
 266         return 1;
 267 }
 268
 269 static int __init maybe_link(void)
 270 {
 271         if (nlink >= 2) {
 272                 char *old = find_link(major, minor, ino, mode, collected);
 273                 if (old)
 274                         return (sys_link(old, collected) < 0) ? -1 : 1;
 275         }
 276         return 0;
 277 }
 278
 279 static void __init clean_path(char *path, mode_t mode)
 280 {
 281         struct stat st;
 282
 283         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
 284                 if (S_ISDIR(st.st_mode))
 285                         sys_rmdir(path);
 286                 else
 287                         sys_unlink(path);
 288         }
 289 }
 290
 291 static __initdata int wfd;
 292
 293 static int __init do_name(void)
 294 {
 295         state = SkipIt;
 296         next_state = Reset;
 297         if (strcmp(collected, "TRAILER!!!") == 0) {
 298                 free_hash();
 299                 return 0;
 300         }
 301         clean_path(collected, mode);
 302         if (S_ISREG(mode)) {
 303                 int ml = maybe_link();
 304                 if (ml >= 0) {
 305                         int openflags = O_WRONLY|O_CREAT;
 306                         if (ml != 1)
 307                                 openflags |= O_TRUNC;
 308                         wfd = sys_open(collected, openflags, mode);
 309
 310                         if (wfd >= 0) {
 311                                 sys_fchown(wfd, uid, gid);
 312                                 sys_fchmod(wfd, mode);
 313                                 if (body_len)
 314                                         sys_ftruncate(wfd, body_len);
 315                                 vcollected = kstrdup(collected, GFP_KERNEL);
 316                                 state = CopyFile;
 317                         }
 318                 }
 319         } else if (S_ISDIR(mode)) {
 320                 sys_mkdir(collected, mode);
 321                 sys_chown(collected, uid, gid);
 322                 sys_chmod(collected, mode);
 323                 dir_add(collected, mtime);
 324         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 325                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 326                 if (maybe_link() == 0) {
 327                         sys_mknod(collected, mode, rdev);
 328                         sys_chown(collected, uid, gid);
 329                         sys_chmod(collected, mode);
 330                         do_utime(collected, mtime);
 331                 }
 332         }
 333         return 0;
 334 }
 335
 336 static int __init do_copy(void)
 337 {
 338         if (count >= body_len) {
 339                 sys_write(wfd, victim, body_len);
 340                 sys_close(wfd);
 341                 do_utime(vcollected, mtime);
 342                 kfree(vcollected);
 343                 eat(body_len);
 344                 state = SkipIt;
 345                 return 0;
 346         } else {
 347                 sys_write(wfd, victim, count);
 348                 body_len -= count;
 349                 eat(count);
 350                 return 1;
 351         }
 352 }
 353
 354 static int __init do_symlink(void)
 355 {
 356         collected[N_ALIGN(name_len) + body_len] = '\0';
 357         clean_path(collected, 0);
 358         sys_symlink(collected + N_ALIGN(name_len), collected);
 359         sys_lchown(collected, uid, gid);
 360         do_utime(collected, mtime);
 361         state = SkipIt;
 362         next_state = Reset;
 363         return 0;
 364 }
 365
 366 static __initdata int (*actions[])(void) = {
 367         [Start]         = do_start,
 368         [Collect]       = do_collect,
 369         [GotHeader]     = do_header,
 370         [SkipIt]        = do_skip,
 371         [GotName]       = do_name,
 372         [CopyFile]      = do_copy,
 373         [GotSymlink]    = do_symlink,
 374         [Reset]         = do_reset,
 375 };
 376
 377 static int __init write_buffer(char *buf, unsigned len)
 378 {
 379         count = len;
 380         victim = buf;
 381
 382         while (!actions[state]())
 383                 ;
 384         return len - count;
 385 }
 386
 387 static int __init flush_buffer(void *bufv, unsigned len)
 388 {
 389         char *buf = (char *) bufv;
 390         int written;
 391         int origLen = len;
 392         if (message)
 393                 return -1;
 394         while ((written = write_buffer(buf, len)) < len && !message) {
 395                 char c = buf[written];
 396                 if (c == '0') {
 397                         buf += written;
 398                         len -= written;
 399                         state = Start;
 400                 } else if (c == 0) {
 401                         buf += written;
 402                         len -= written;
 403                         state = Reset;
 404                 } else
 405                         error("junk in compressed archive");
 406         }
 407         return origLen;
 408 }
 409
 410 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
 411
 412 #include <linux/decompress/generic.h>
 413
 414 static char * __init unpack_to_rootfs(char *buf, unsigned len)
 415 {
 416         int written, res;
 417         decompress_fn decompress;
 418         const char *compress_name;
 419         static __initdata char msg_buf[64];
 420
 421         header_buf = kmalloc(110, GFP_KERNEL);
 422         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 423         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 424
 425         if (!header_buf || !symlink_buf || !name_buf)
 426                 panic("can't allocate buffers");
 427
 428         state = Start;
 429         this_header = 0;
 430         message = NULL;
 431         while (!message && len) {
 432                 loff_t saved_offset = this_header;
 433                 if (*buf == '0' && !(this_header & 3)) {
 434                         state = Start;
 435                         written = write_buffer(buf, len);
 436                         buf += written;
 437                         len -= written;
 438                         continue;
 439                 }
 440                 if (!*buf) {
 441                         buf++;
 442                         len--;
 443                         this_header++;
 444                         continue;
 445                 }
 446                 this_header = 0;
 447                 decompress = decompress_method(buf, len, &compress_name);
 448                 if (decompress) {
 449                         res = decompress(buf, len, NULL, flush_buffer, NULL,
 450                                    &my_inptr, error);
 451                         if (res)
 452                                 error("decompressor failed");
 453                 } else if (compress_name) {
 454                         if (!message) {
 455                                 snprintf(msg_buf, sizeof msg_buf,
 456                                          "compression method %s not configured",
 457                                          compress_name);
 458                                 message = msg_buf;
 459                         }
 460                 }
 461                 if (state != Reset)
 462                         error("junk in compressed archive");
 463                 this_header = saved_offset + my_inptr;
 464                 buf += my_inptr;
 465                 len -= my_inptr;
 466         }
 467         dir_utime();
 468         kfree(name_buf);
 469         kfree(symlink_buf);
 470         kfree(header_buf);
 471         return message;
 472 }
 473
 474 static int __initdata do_retain_initrd;
 475
 476 static int __init retain_initrd_param(char *str)
 477 {
 478         if (*str)
 479                 return 0;
 480         do_retain_initrd = 1;
 481         return 1;
 482 }
 483 __setup("retain_initrd", retain_initrd_param);
 484
 485 extern char __initramfs_start[], __initramfs_end[];
 486 #include <linux/initrd.h>
 487 #include <linux/kexec.h>
 488
 489 static void __init free_initrd(void)
 490 {
 491 #ifdef CONFIG_KEXEC
 492         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 493         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 494 #endif
 495         if (do_retain_initrd)
 496                 goto skip;
 497
 498 #ifdef CONFIG_KEXEC
 499         /*
 500          * If the initrd region is overlapped with crashkernel reserved region,
 501          * free only memory that is not part of crashkernel region.
 502          */
 503         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 504                 /*
 505                  * Initialize initrd memory region since the kexec boot does
 506                  * not do.
 507                  */
 508                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 509                 if (initrd_start < crashk_start)
 510                         free_initrd_mem(initrd_start, crashk_start);
 511                 if (initrd_end > crashk_end)
 512                         free_initrd_mem(crashk_end, initrd_end);
 513         } else
 514 #endif
 515                 free_initrd_mem(initrd_start, initrd_end);
 516 skip:
 517         initrd_start = 0;
 518         initrd_end = 0;
 519 }
 520
 521 #ifdef CONFIG_BLK_DEV_RAM
 522 #define BUF_SIZE 1024
 523 static void __init clean_rootfs(void)
 524 {
 525         int fd;
 526         void *buf;
 527         struct linux_dirent64 *dirp;
 528         int count;
 529
 530         fd = sys_open("/", O_RDONLY, 0);
 531         WARN_ON(fd < 0);
 532         if (fd < 0)
 533                 return;
 534         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 535         WARN_ON(!buf);
 536         if (!buf) {
 537                 sys_close(fd);
 538                 return;
 539         }
 540
 541         dirp = buf;
 542         count = sys_getdents64(fd, dirp, BUF_SIZE);
 543         while (count > 0) {
 544                 while (count > 0) {
 545                         struct stat st;
 546                         int ret;
 547
 548                         ret = sys_newlstat(dirp->d_name, &st);
 549                         WARN_ON_ONCE(ret);
 550                         if (!ret) {
 551                                 if (S_ISDIR(st.st_mode))
 552                                         sys_rmdir(dirp->d_name);
 553                                 else
 554                                         sys_unlink(dirp->d_name);
 555                         }
 556
 557                         count -= dirp->d_reclen;
 558                         dirp = (void *)dirp + dirp->d_reclen;
 559                 }
 560                 dirp = buf;
 561                 memset(buf, 0, BUF_SIZE);
 562                 count = sys_getdents64(fd, dirp, BUF_SIZE);
 563         }
 564
 565         sys_close(fd);
 566         kfree(buf);
 567 }
 568 #endif
 569
 570 static int __init populate_rootfs(void)
 571 {
 572         char *err = unpack_to_rootfs(__initramfs_start,
 573                          __initramfs_end - __initramfs_start);
 574         if (err)
 575                 panic(err);     /* Failed to decompress INTERNAL initramfs */
 576         if (initrd_start) {
 577 #ifdef CONFIG_BLK_DEV_RAM
 578                 int fd;
 579                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 580                 err = unpack_to_rootfs((char *)initrd_start,
 581                         initrd_end - initrd_start);
 582                 if (!err) {
 583                         free_initrd();
 584                         return 0;
 585                 } else {
 586                         clean_rootfs();
 587                         unpack_to_rootfs(__initramfs_start,
 588                                  __initramfs_end - __initramfs_start);
 589                 }
 590                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
 591                                 "; looks like an initrd\n", err);
 592                 fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700);
 593                 if (fd >= 0) {
 594                         sys_write(fd, (char *)initrd_start,
 595                                         initrd_end - initrd_start);
 596                         sys_close(fd);
 597                         free_initrd();
 598                 }
 599 #else
 600                 printk(KERN_INFO "Unpacking initramfs...\n");
 601                 err = unpack_to_rootfs((char *)initrd_start,
 602                         initrd_end - initrd_start);
 603                 if (err)
 604                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 605                 free_initrd();
 606 #endif
 607         }
 608         return 0;
 609 }
 610 rootfs_initcall(populate_rootfs);