init/initramfs.c

   1 /*
   2  * Many of the syscalls used in this file expect some of the arguments
   3  * to be __user pointers not __kernel pointers.  To limit the sparse
   4  * noise, turn off sparse checking for this file.
   5  */
   6 #ifdef __CHECKER__
   7 #undef __CHECKER__
   8 #warning "Sparse checking disabled for this file"
   9 #endif
  10
  11 #include <linux/init.h>
  12 #include <linux/fs.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/fcntl.h>
  16 #include <linux/delay.h>
  17 #include <linux/string.h>
  18 #include <linux/dirent.h>
  19 #include <linux/syscalls.h>
  20 #include <linux/utime.h>
  21
  22 static __initdata char *message;
  23 static void __init error(char *x)
  24 {
  25         if (!message)
  26                 message = x;
  27 }
  28
  29 /* link hash */
  30
  31 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  32
  33 static __initdata struct hash {
  34         int ino, minor, major;
  35         umode_t mode;
  36         struct hash *next;
  37         char name[N_ALIGN(PATH_MAX)];
  38 } *head[32];
  39
  40 static inline int hash(int major, int minor, int ino)
  41 {
  42         unsigned long tmp = ino + minor + (major << 3);
  43         tmp += tmp >> 5;
  44         return tmp & 31;
  45 }
  46
  47 static char __init *find_link(int major, int minor, int ino,
  48                               umode_t mode, char *name)
  49 {
  50         struct hash **p, *q;
  51         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  52                 if ((*p)->ino != ino)
  53                         continue;
  54                 if ((*p)->minor != minor)
  55                         continue;
  56                 if ((*p)->major != major)
  57                         continue;
  58                 if (((*p)->mode ^ mode) & S_IFMT)
  59                         continue;
  60                 return (*p)->name;
  61         }
  62         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  63         if (!q)
  64                 panic("can't allocate link hash entry");
  65         q->major = major;
  66         q->minor = minor;
  67         q->ino = ino;
  68         q->mode = mode;
  69         strcpy(q->name, name);
  70         q->next = NULL;
  71         *p = q;
  72         return NULL;
  73 }
  74
  75 static void __init free_hash(void)
  76 {
  77         struct hash **p, *q;
  78         for (p = head; p < head + 32; p++) {
  79                 while (*p) {
  80                         q = *p;
  81                         *p = q->next;
  82                         kfree(q);
  83                 }
  84         }
  85 }
  86
  87 static long __init do_utime(char *filename, time_t mtime)
  88 {
  89         struct timespec t[2];
  90
  91         t[0].tv_sec = mtime;
  92         t[0].tv_nsec = 0;
  93         t[1].tv_sec = mtime;
  94         t[1].tv_nsec = 0;
  95
  96         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
  97 }
  98
  99 static __initdata LIST_HEAD(dir_list);
 100 struct dir_entry {
 101         struct list_head list;
 102         char *name;
 103         time_t mtime;
 104 };
 105
 106 static void __init dir_add(const char *name, time_t mtime)
 107 {
 108         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 109         if (!de)
 110                 panic("can't allocate dir_entry buffer");
 111         INIT_LIST_HEAD(&de->list);
 112         de->name = kstrdup(name, GFP_KERNEL);
 113         de->mtime = mtime;
 114         list_add(&de->list, &dir_list);
 115 }
 116
 117 static void __init dir_utime(void)
 118 {
 119         struct dir_entry *de, *tmp;
 120         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 121                 list_del(&de->list);
 122                 do_utime(de->name, de->mtime);
 123                 kfree(de->name);
 124                 kfree(de);
 125         }
 126 }
 127
 128 static __initdata time_t mtime;
 129
 130 /* cpio header parsing */
 131
 132 static __initdata unsigned long ino, major, minor, nlink;
 133 static __initdata umode_t mode;
 134 static __initdata unsigned long body_len, name_len;
 135 static __initdata uid_t uid;
 136 static __initdata gid_t gid;
 137 static __initdata unsigned rdev;
 138
 139 static void __init parse_header(char *s)
 140 {
 141         unsigned long parsed[12];
 142         char buf[9];
 143         int i;
 144
 145         buf[8] = '\0';
 146         for (i = 0, s += 6; i < 12; i++, s += 8) {
 147                 memcpy(buf, s, 8);
 148                 parsed[i] = simple_strtoul(buf, NULL, 16);
 149         }
 150         ino = parsed[0];
 151         mode = parsed[1];
 152         uid = parsed[2];
 153         gid = parsed[3];
 154         nlink = parsed[4];
 155         mtime = parsed[5];
 156         body_len = parsed[6];
 157         major = parsed[7];
 158         minor = parsed[8];
 159         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 160         name_len = parsed[11];
 161 }
 162
 163 /* FSM */
 164
 165 static __initdata enum state {
 166         Start,
 167         Collect,
 168         GotHeader,
 169         SkipIt,
 170         GotName,
 171         CopyFile,
 172         GotSymlink,
 173         Reset
 174 } state, next_state;
 175
 176 static __initdata char *victim;
 177 static __initdata unsigned count;
 178 static __initdata loff_t this_header, next_header;
 179
 180 static inline void __init eat(unsigned n)
 181 {
 182         victim += n;
 183         this_header += n;
 184         count -= n;
 185 }
 186
 187 static __initdata char *vcollected;
 188 static __initdata char *collected;
 189 static __initdata int remains;
 190 static __initdata char *collect;
 191
 192 static void __init read_into(char *buf, unsigned size, enum state next)
 193 {
 194         if (count >= size) {
 195                 collected = victim;
 196                 eat(size);
 197                 state = next;
 198         } else {
 199                 collect = collected = buf;
 200                 remains = size;
 201                 next_state = next;
 202                 state = Collect;
 203         }
 204 }
 205
 206 static __initdata char *header_buf, *symlink_buf, *name_buf;
 207
 208 static int __init do_start(void)
 209 {
 210         read_into(header_buf, 110, GotHeader);
 211         return 0;
 212 }
 213
 214 static int __init do_collect(void)
 215 {
 216         unsigned n = remains;
 217         if (count < n)
 218                 n = count;
 219         memcpy(collect, victim, n);
 220         eat(n);
 221         collect += n;
 222         if ((remains -= n) != 0)
 223                 return 1;
 224         state = next_state;
 225         return 0;
 226 }
 227
 228 static int __init do_header(void)
 229 {
 230         if (memcmp(collected, "070707", 6)==0) {
 231                 error("incorrect cpio method used: use -H newc option");
 232                 return 1;
 233         }
 234         if (memcmp(collected, "070701", 6)) {
 235                 error("no cpio magic");
 236                 return 1;
 237         }
 238         parse_header(collected);
 239         next_header = this_header + N_ALIGN(name_len) + body_len;
 240         next_header = (next_header + 3) & ~3;
 241         state = SkipIt;
 242         if (name_len <= 0 || name_len > PATH_MAX)
 243                 return 0;
 244         if (S_ISLNK(mode)) {
 245                 if (body_len > PATH_MAX)
 246                         return 0;
 247                 collect = collected = symlink_buf;
 248                 remains = N_ALIGN(name_len) + body_len;
 249                 next_state = GotSymlink;
 250                 state = Collect;
 251                 return 0;
 252         }
 253         if (S_ISREG(mode) || !body_len)
 254                 read_into(name_buf, N_ALIGN(name_len), GotName);
 255         return 0;
 256 }
 257
 258 static int __init do_skip(void)
 259 {
 260         if (this_header + count < next_header) {
 261                 eat(count);
 262                 return 1;
 263         } else {
 264                 eat(next_header - this_header);
 265                 state = next_state;
 266                 return 0;
 267         }
 268 }
 269
 270 static int __init do_reset(void)
 271 {
 272         while(count && *victim == '\0')
 273                 eat(1);
 274         if (count && (this_header & 3))
 275                 error("broken padding");
 276         return 1;
 277 }
 278
 279 static int __init maybe_link(void)
 280 {
 281         if (nlink >= 2) {
 282                 char *old = find_link(major, minor, ino, mode, collected);
 283                 if (old)
 284                         return (sys_link(old, collected) < 0) ? -1 : 1;
 285         }
 286         return 0;
 287 }
 288
 289 static void __init clean_path(char *path, umode_t mode)
 290 {
 291         struct stat st;
 292
 293         if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
 294                 if (S_ISDIR(st.st_mode))
 295                         sys_rmdir(path);
 296                 else
 297                         sys_unlink(path);
 298         }
 299 }
 300
 301 static __initdata int wfd;
 302
 303 static int __init do_name(void)
 304 {
 305         state = SkipIt;
 306         next_state = Reset;
 307         if (strcmp(collected, "TRAILER!!!") == 0) {
 308                 free_hash();
 309                 return 0;
 310         }
 311         clean_path(collected, mode);
 312         if (S_ISREG(mode)) {
 313                 int ml = maybe_link();
 314                 if (ml >= 0) {
 315                         int openflags = O_WRONLY|O_CREAT;
 316                         if (ml != 1)
 317                                 openflags |= O_TRUNC;
 318                         wfd = sys_open(collected, openflags, mode);
 319
 320                         if (wfd >= 0) {
 321                                 sys_fchown(wfd, uid, gid);
 322                                 sys_fchmod(wfd, mode);
 323                                 if (body_len)
 324                                         sys_ftruncate(wfd, body_len);
 325                                 vcollected = kstrdup(collected, GFP_KERNEL);
 326                                 state = CopyFile;
 327                         }
 328                 }
 329         } else if (S_ISDIR(mode)) {
 330                 sys_mkdir(collected, mode);
 331                 sys_chown(collected, uid, gid);
 332                 sys_chmod(collected, mode);
 333                 dir_add(collected, mtime);
 334         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 335                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 336                 if (maybe_link() == 0) {
 337                         sys_mknod(collected, mode, rdev);
 338                         sys_chown(collected, uid, gid);
 339                         sys_chmod(collected, mode);
 340                         do_utime(collected, mtime);
 341                 }
 342         }
 343         return 0;
 344 }
 345
 346 static int __init do_copy(void)
 347 {
 348         if (count >= body_len) {
 349                 sys_write(wfd, victim, body_len);
 350                 sys_close(wfd);
 351                 do_utime(vcollected, mtime);
 352                 kfree(vcollected);
 353                 eat(body_len);
 354                 state = SkipIt;
 355                 return 0;
 356         } else {
 357                 sys_write(wfd, victim, count);
 358                 body_len -= count;
 359                 eat(count);
 360                 return 1;
 361         }
 362 }
 363
 364 static int __init do_symlink(void)
 365 {
 366         collected[N_ALIGN(name_len) + body_len] = '\0';
 367         clean_path(collected, 0);
 368         sys_symlink(collected + N_ALIGN(name_len), collected);
 369         sys_lchown(collected, uid, gid);
 370         do_utime(collected, mtime);
 371         state = SkipIt;
 372         next_state = Reset;
 373         return 0;
 374 }
 375
 376 static __initdata int (*actions[])(void) = {
 377         [Start]         = do_start,
 378         [Collect]       = do_collect,
 379         [GotHeader]     = do_header,
 380         [SkipIt]        = do_skip,
 381         [GotName]       = do_name,
 382         [CopyFile]      = do_copy,
 383         [GotSymlink]    = do_symlink,
 384         [Reset]         = do_reset,
 385 };
 386
 387 static int __init write_buffer(char *buf, unsigned len)
 388 {
 389         count = len;
 390         victim = buf;
 391
 392         while (!actions[state]())
 393                 ;
 394         return len - count;
 395 }
 396
 397 static int __init flush_buffer(void *bufv, unsigned len)
 398 {
 399         char *buf = (char *) bufv;
 400         int written;
 401         int origLen = len;
 402         if (message)
 403                 return -1;
 404         while ((written = write_buffer(buf, len)) < len && !message) {
 405                 char c = buf[written];
 406                 if (c == '0') {
 407                         buf += written;
 408                         len -= written;
 409                         state = Start;
 410                 } else if (c == 0) {
 411                         buf += written;
 412                         len -= written;
 413                         state = Reset;
 414                 } else
 415                         error("junk in compressed archive");
 416         }
 417         return origLen;
 418 }
 419
 420 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
 421
 422 #include <linux/decompress/generic.h>
 423
 424 static char * __init unpack_to_rootfs(char *buf, unsigned len)
 425 {
 426         int written, res;
 427         decompress_fn decompress;
 428         const char *compress_name;
 429         static __initdata char msg_buf[64];
 430
 431         header_buf = kmalloc(110, GFP_KERNEL);
 432         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 433         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 434
 435         if (!header_buf || !symlink_buf || !name_buf)
 436                 panic("can't allocate buffers");
 437
 438         state = Start;
 439         this_header = 0;
 440         message = NULL;
 441         while (!message && len) {
 442                 loff_t saved_offset = this_header;
 443                 if (*buf == '0' && !(this_header & 3)) {
 444                         state = Start;
 445                         written = write_buffer(buf, len);
 446                         buf += written;
 447                         len -= written;
 448                         continue;
 449                 }
 450                 if (!*buf) {
 451                         buf++;
 452                         len--;
 453                         this_header++;
 454                         continue;
 455                 }
 456                 this_header = 0;
 457                 decompress = decompress_method(buf, len, &compress_name);
 458                 pr_debug("Detected %s compressed data\n", compress_name);
 459                 if (decompress) {
 460                         res = decompress(buf, len, NULL, flush_buffer, NULL,
 461                                    &my_inptr, error);
 462                         if (res)
 463                                 error("decompressor failed");
 464                 } else if (compress_name) {
 465                         if (!message) {
 466                                 snprintf(msg_buf, sizeof msg_buf,
 467                                          "compression method %s not configured",
 468                                          compress_name);
 469                                 message = msg_buf;
 470                         }
 471                 } else
 472                         error("junk in compressed archive");
 473                 if (state != Reset)
 474                         error("junk in compressed archive");
 475                 this_header = saved_offset + my_inptr;
 476                 buf += my_inptr;
 477                 len -= my_inptr;
 478         }
 479         dir_utime();
 480         kfree(name_buf);
 481         kfree(symlink_buf);
 482         kfree(header_buf);
 483         return message;
 484 }
 485
 486 static int __initdata do_retain_initrd;
 487
 488 static int __init retain_initrd_param(char *str)
 489 {
 490         if (*str)
 491                 return 0;
 492         do_retain_initrd = 1;
 493         return 1;
 494 }
 495 __setup("retain_initrd", retain_initrd_param);
 496
 497 extern char __initramfs_start[];
 498 extern unsigned long __initramfs_size;
 499 #include <linux/initrd.h>
 500 #include <linux/kexec.h>
 501
 502 static void __init free_initrd(void)
 503 {
 504 #ifdef CONFIG_KEXEC
 505         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 506         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 507 #endif
 508         if (do_retain_initrd)
 509                 goto skip;
 510
 511 #ifdef CONFIG_KEXEC
 512         /*
 513          * If the initrd region is overlapped with crashkernel reserved region,
 514          * free only memory that is not part of crashkernel region.
 515          */
 516         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 517                 /*
 518                  * Initialize initrd memory region since the kexec boot does
 519                  * not do.
 520                  */
 521                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 522                 if (initrd_start < crashk_start)
 523                         free_initrd_mem(initrd_start, crashk_start);
 524                 if (initrd_end > crashk_end)
 525                         free_initrd_mem(crashk_end, initrd_end);
 526         } else
 527 #endif
 528                 free_initrd_mem(initrd_start, initrd_end);
 529 skip:
 530         initrd_start = 0;
 531         initrd_end = 0;
 532 }
 533
 534 #ifdef CONFIG_BLK_DEV_RAM
 535 #define BUF_SIZE 1024
 536 static void __init clean_rootfs(void)
 537 {
 538         int fd;
 539         void *buf;
 540         struct linux_dirent64 *dirp;
 541         int num;
 542
 543         fd = sys_open("/", O_RDONLY, 0);
 544         WARN_ON(fd < 0);
 545         if (fd < 0)
 546                 return;
 547         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 548         WARN_ON(!buf);
 549         if (!buf) {
 550                 sys_close(fd);
 551                 return;
 552         }
 553
 554         dirp = buf;
 555         num = sys_getdents64(fd, dirp, BUF_SIZE);
 556         while (num > 0) {
 557                 while (num > 0) {
 558                         struct stat st;
 559                         int ret;
 560
 561                         ret = sys_newlstat(dirp->d_name, &st);
 562                         WARN_ON_ONCE(ret);
 563                         if (!ret) {
 564                                 if (S_ISDIR(st.st_mode))
 565                                         sys_rmdir(dirp->d_name);
 566                                 else
 567                                         sys_unlink(dirp->d_name);
 568                         }
 569
 570                         num -= dirp->d_reclen;
 571                         dirp = (void *)dirp + dirp->d_reclen;
 572                 }
 573                 dirp = buf;
 574                 memset(buf, 0, BUF_SIZE);
 575                 num = sys_getdents64(fd, dirp, BUF_SIZE);
 576         }
 577
 578         sys_close(fd);
 579         kfree(buf);
 580 }
 581 #endif
 582
 583 static int __init populate_rootfs(void)
 584 {
 585         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 586         if (err)
 587                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 588         if (initrd_start) {
 589 #ifdef CONFIG_BLK_DEV_RAM
 590                 int fd;
 591                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 592                 err = unpack_to_rootfs((char *)initrd_start,
 593                         initrd_end - initrd_start);
 594                 if (!err) {
 595                         free_initrd();
 596                         goto done;
 597                 } else {
 598                         clean_rootfs();
 599                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 600                 }
 601                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
 602                                 "; looks like an initrd\n", err);
 603                 fd = sys_open("/initrd.image",
 604                               O_WRONLY|O_CREAT, 0700);
 605                 if (fd >= 0) {
 606                         sys_write(fd, (char *)initrd_start,
 607                                         initrd_end - initrd_start);
 608                         sys_close(fd);
 609                         free_initrd();
 610                 }
 611         done:
 612 #else
 613                 printk(KERN_INFO "Unpacking initramfs...\n");
 614                 err = unpack_to_rootfs((char *)initrd_start,
 615                         initrd_end - initrd_start);
 616                 if (err)
 617                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 618                 free_initrd();
 619 #endif
 620                 /*
 621                  * Try loading default modules from initramfs.  This gives
 622                  * us a chance to load before device_initcalls.
 623                  */
 624                 load_default_modules();
 625         }
 626         return 0;
 627 }
 628 rootfs_initcall(populate_rootfs);