init/initramfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   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/delay.h>
   8 #include <linux/string.h>
   9 #include <linux/dirent.h>
  10 #include <linux/syscalls.h>
  11 #include <linux/utime.h>
  12 #include <linux/file.h>
  13 #include <linux/memblock.h>
  14
  15 static ssize_t __init xwrite(int fd, const char *p, size_t count)
  16 {
  17         ssize_t out = 0;
  18
  19         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  20         while (count) {
  21                 ssize_t rv = ksys_write(fd, p, count);
  22
  23                 if (rv < 0) {
  24                         if (rv == -EINTR || rv == -EAGAIN)
  25                                 continue;
  26                         return out ? out : rv;
  27                 } else if (rv == 0)
  28                         break;
  29
  30                 p += rv;
  31                 out += rv;
  32                 count -= rv;
  33         }
  34
  35         return out;
  36 }
  37
  38 static __initdata char *message;
  39 static void __init error(char *x)
  40 {
  41         if (!message)
  42                 message = x;
  43 }
  44
  45 /* link hash */
  46
  47 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  48
  49 static __initdata struct hash {
  50         int ino, minor, major;
  51         umode_t mode;
  52         struct hash *next;
  53         char name[N_ALIGN(PATH_MAX)];
  54 } *head[32];
  55
  56 static inline int hash(int major, int minor, int ino)
  57 {
  58         unsigned long tmp = ino + minor + (major << 3);
  59         tmp += tmp >> 5;
  60         return tmp & 31;
  61 }
  62
  63 static char __init *find_link(int major, int minor, int ino,
  64                               umode_t mode, char *name)
  65 {
  66         struct hash **p, *q;
  67         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  68                 if ((*p)->ino != ino)
  69                         continue;
  70                 if ((*p)->minor != minor)
  71                         continue;
  72                 if ((*p)->major != major)
  73                         continue;
  74                 if (((*p)->mode ^ mode) & S_IFMT)
  75                         continue;
  76                 return (*p)->name;
  77         }
  78         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  79         if (!q)
  80                 panic("can't allocate link hash entry");
  81         q->major = major;
  82         q->minor = minor;
  83         q->ino = ino;
  84         q->mode = mode;
  85         strcpy(q->name, name);
  86         q->next = NULL;
  87         *p = q;
  88         return NULL;
  89 }
  90
  91 static void __init free_hash(void)
  92 {
  93         struct hash **p, *q;
  94         for (p = head; p < head + 32; p++) {
  95                 while (*p) {
  96                         q = *p;
  97                         *p = q->next;
  98                         kfree(q);
  99                 }
 100         }
 101 }
 102
 103 static long __init do_utime(char *filename, time64_t mtime)
 104 {
 105         struct timespec64 t[2];
 106
 107         t[0].tv_sec = mtime;
 108         t[0].tv_nsec = 0;
 109         t[1].tv_sec = mtime;
 110         t[1].tv_nsec = 0;
 111
 112         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
 113 }
 114
 115 static __initdata LIST_HEAD(dir_list);
 116 struct dir_entry {
 117         struct list_head list;
 118         char *name;
 119         time64_t mtime;
 120 };
 121
 122 static void __init dir_add(const char *name, time64_t mtime)
 123 {
 124         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 125         if (!de)
 126                 panic("can't allocate dir_entry buffer");
 127         INIT_LIST_HEAD(&de->list);
 128         de->name = kstrdup(name, GFP_KERNEL);
 129         de->mtime = mtime;
 130         list_add(&de->list, &dir_list);
 131 }
 132
 133 static void __init dir_utime(void)
 134 {
 135         struct dir_entry *de, *tmp;
 136         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 137                 list_del(&de->list);
 138                 do_utime(de->name, de->mtime);
 139                 kfree(de->name);
 140                 kfree(de);
 141         }
 142 }
 143
 144 static __initdata time64_t mtime;
 145
 146 /* cpio header parsing */
 147
 148 static __initdata unsigned long ino, major, minor, nlink;
 149 static __initdata umode_t mode;
 150 static __initdata unsigned long body_len, name_len;
 151 static __initdata uid_t uid;
 152 static __initdata gid_t gid;
 153 static __initdata unsigned rdev;
 154
 155 static void __init parse_header(char *s)
 156 {
 157         unsigned long parsed[12];
 158         char buf[9];
 159         int i;
 160
 161         buf[8] = '\0';
 162         for (i = 0, s += 6; i < 12; i++, s += 8) {
 163                 memcpy(buf, s, 8);
 164                 parsed[i] = simple_strtoul(buf, NULL, 16);
 165         }
 166         ino = parsed[0];
 167         mode = parsed[1];
 168         uid = parsed[2];
 169         gid = parsed[3];
 170         nlink = parsed[4];
 171         mtime = parsed[5]; /* breaks in y2106 */
 172         body_len = parsed[6];
 173         major = parsed[7];
 174         minor = parsed[8];
 175         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 176         name_len = parsed[11];
 177 }
 178
 179 /* FSM */
 180
 181 static __initdata enum state {
 182         Start,
 183         Collect,
 184         GotHeader,
 185         SkipIt,
 186         GotName,
 187         CopyFile,
 188         GotSymlink,
 189         Reset
 190 } state, next_state;
 191
 192 static __initdata char *victim;
 193 static unsigned long byte_count __initdata;
 194 static __initdata loff_t this_header, next_header;
 195
 196 static inline void __init eat(unsigned n)
 197 {
 198         victim += n;
 199         this_header += n;
 200         byte_count -= n;
 201 }
 202
 203 static __initdata char *vcollected;
 204 static __initdata char *collected;
 205 static long remains __initdata;
 206 static __initdata char *collect;
 207
 208 static void __init read_into(char *buf, unsigned size, enum state next)
 209 {
 210         if (byte_count >= size) {
 211                 collected = victim;
 212                 eat(size);
 213                 state = next;
 214         } else {
 215                 collect = collected = buf;
 216                 remains = size;
 217                 next_state = next;
 218                 state = Collect;
 219         }
 220 }
 221
 222 static __initdata char *header_buf, *symlink_buf, *name_buf;
 223
 224 static int __init do_start(void)
 225 {
 226         read_into(header_buf, 110, GotHeader);
 227         return 0;
 228 }
 229
 230 static int __init do_collect(void)
 231 {
 232         unsigned long n = remains;
 233         if (byte_count < n)
 234                 n = byte_count;
 235         memcpy(collect, victim, n);
 236         eat(n);
 237         collect += n;
 238         if ((remains -= n) != 0)
 239                 return 1;
 240         state = next_state;
 241         return 0;
 242 }
 243
 244 static int __init do_header(void)
 245 {
 246         if (memcmp(collected, "070707", 6)==0) {
 247                 error("incorrect cpio method used: use -H newc option");
 248                 return 1;
 249         }
 250         if (memcmp(collected, "070701", 6)) {
 251                 error("no cpio magic");
 252                 return 1;
 253         }
 254         parse_header(collected);
 255         next_header = this_header + N_ALIGN(name_len) + body_len;
 256         next_header = (next_header + 3) & ~3;
 257         state = SkipIt;
 258         if (name_len <= 0 || name_len > PATH_MAX)
 259                 return 0;
 260         if (S_ISLNK(mode)) {
 261                 if (body_len > PATH_MAX)
 262                         return 0;
 263                 collect = collected = symlink_buf;
 264                 remains = N_ALIGN(name_len) + body_len;
 265                 next_state = GotSymlink;
 266                 state = Collect;
 267                 return 0;
 268         }
 269         if (S_ISREG(mode) || !body_len)
 270                 read_into(name_buf, N_ALIGN(name_len), GotName);
 271         return 0;
 272 }
 273
 274 static int __init do_skip(void)
 275 {
 276         if (this_header + byte_count < next_header) {
 277                 eat(byte_count);
 278                 return 1;
 279         } else {
 280                 eat(next_header - this_header);
 281                 state = next_state;
 282                 return 0;
 283         }
 284 }
 285
 286 static int __init do_reset(void)
 287 {
 288         while (byte_count && *victim == '\0')
 289                 eat(1);
 290         if (byte_count && (this_header & 3))
 291                 error("broken padding");
 292         return 1;
 293 }
 294
 295 static void __init clean_path(char *path, umode_t fmode)
 296 {
 297         struct kstat st;
 298
 299         if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
 300                 if (S_ISDIR(st.mode))
 301                         ksys_rmdir(path);
 302                 else
 303                         ksys_unlink(path);
 304         }
 305 }
 306
 307 static int __init maybe_link(void)
 308 {
 309         if (nlink >= 2) {
 310                 char *old = find_link(major, minor, ino, mode, collected);
 311                 if (old) {
 312                         clean_path(collected, 0);
 313                         return (ksys_link(old, collected) < 0) ? -1 : 1;
 314                 }
 315         }
 316         return 0;
 317 }
 318
 319 static __initdata int wfd;
 320
 321 static int __init do_name(void)
 322 {
 323         state = SkipIt;
 324         next_state = Reset;
 325         if (strcmp(collected, "TRAILER!!!") == 0) {
 326                 free_hash();
 327                 return 0;
 328         }
 329         clean_path(collected, mode);
 330         if (S_ISREG(mode)) {
 331                 int ml = maybe_link();
 332                 if (ml >= 0) {
 333                         int openflags = O_WRONLY|O_CREAT;
 334                         if (ml != 1)
 335                                 openflags |= O_TRUNC;
 336                         wfd = ksys_open(collected, openflags, mode);
 337
 338                         if (wfd >= 0) {
 339                                 ksys_fchown(wfd, uid, gid);
 340                                 ksys_fchmod(wfd, mode);
 341                                 if (body_len)
 342                                         ksys_ftruncate(wfd, body_len);
 343                                 vcollected = kstrdup(collected, GFP_KERNEL);
 344                                 state = CopyFile;
 345                         }
 346                 }
 347         } else if (S_ISDIR(mode)) {
 348                 ksys_mkdir(collected, mode);
 349                 ksys_chown(collected, uid, gid);
 350                 ksys_chmod(collected, mode);
 351                 dir_add(collected, mtime);
 352         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 353                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 354                 if (maybe_link() == 0) {
 355                         ksys_mknod(collected, mode, rdev);
 356                         ksys_chown(collected, uid, gid);
 357                         ksys_chmod(collected, mode);
 358                         do_utime(collected, mtime);
 359                 }
 360         }
 361         return 0;
 362 }
 363
 364 static int __init do_copy(void)
 365 {
 366         if (byte_count >= body_len) {
 367                 if (xwrite(wfd, victim, body_len) != body_len)
 368                         error("write error");
 369                 ksys_close(wfd);
 370                 do_utime(vcollected, mtime);
 371                 kfree(vcollected);
 372                 eat(body_len);
 373                 state = SkipIt;
 374                 return 0;
 375         } else {
 376                 if (xwrite(wfd, victim, byte_count) != byte_count)
 377                         error("write error");
 378                 body_len -= byte_count;
 379                 eat(byte_count);
 380                 return 1;
 381         }
 382 }
 383
 384 static int __init do_symlink(void)
 385 {
 386         collected[N_ALIGN(name_len) + body_len] = '\0';
 387         clean_path(collected, 0);
 388         ksys_symlink(collected + N_ALIGN(name_len), collected);
 389         ksys_lchown(collected, uid, gid);
 390         do_utime(collected, mtime);
 391         state = SkipIt;
 392         next_state = Reset;
 393         return 0;
 394 }
 395
 396 static __initdata int (*actions[])(void) = {
 397         [Start]         = do_start,
 398         [Collect]       = do_collect,
 399         [GotHeader]     = do_header,
 400         [SkipIt]        = do_skip,
 401         [GotName]       = do_name,
 402         [CopyFile]      = do_copy,
 403         [GotSymlink]    = do_symlink,
 404         [Reset]         = do_reset,
 405 };
 406
 407 static long __init write_buffer(char *buf, unsigned long len)
 408 {
 409         byte_count = len;
 410         victim = buf;
 411
 412         while (!actions[state]())
 413                 ;
 414         return len - byte_count;
 415 }
 416
 417 static long __init flush_buffer(void *bufv, unsigned long len)
 418 {
 419         char *buf = (char *) bufv;
 420         long written;
 421         long origLen = len;
 422         if (message)
 423                 return -1;
 424         while ((written = write_buffer(buf, len)) < len && !message) {
 425                 char c = buf[written];
 426                 if (c == '0') {
 427                         buf += written;
 428                         len -= written;
 429                         state = Start;
 430                 } else if (c == 0) {
 431                         buf += written;
 432                         len -= written;
 433                         state = Reset;
 434                 } else
 435                         error("junk within compressed archive");
 436         }
 437         return origLen;
 438 }
 439
 440 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 441
 442 #include <linux/decompress/generic.h>
 443
 444 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 445 {
 446         long written;
 447         decompress_fn decompress;
 448         const char *compress_name;
 449         static __initdata char msg_buf[64];
 450
 451         header_buf = kmalloc(110, GFP_KERNEL);
 452         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 453         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 454
 455         if (!header_buf || !symlink_buf || !name_buf)
 456                 panic("can't allocate buffers");
 457
 458         state = Start;
 459         this_header = 0;
 460         message = NULL;
 461         while (!message && len) {
 462                 loff_t saved_offset = this_header;
 463                 if (*buf == '0' && !(this_header & 3)) {
 464                         state = Start;
 465                         written = write_buffer(buf, len);
 466                         buf += written;
 467                         len -= written;
 468                         continue;
 469                 }
 470                 if (!*buf) {
 471                         buf++;
 472                         len--;
 473                         this_header++;
 474                         continue;
 475                 }
 476                 this_header = 0;
 477                 decompress = decompress_method(buf, len, &compress_name);
 478                 pr_debug("Detected %s compressed data\n", compress_name);
 479                 if (decompress) {
 480                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
 481                                    &my_inptr, error);
 482                         if (res)
 483                                 error("decompressor failed");
 484                 } else if (compress_name) {
 485                         if (!message) {
 486                                 snprintf(msg_buf, sizeof msg_buf,
 487                                          "compression method %s not configured",
 488                                          compress_name);
 489                                 message = msg_buf;
 490                         }
 491                 } else
 492                         error("invalid magic at start of compressed archive");
 493                 if (state != Reset)
 494                         error("junk at the end of compressed archive");
 495                 this_header = saved_offset + my_inptr;
 496                 buf += my_inptr;
 497                 len -= my_inptr;
 498         }
 499         dir_utime();
 500         kfree(name_buf);
 501         kfree(symlink_buf);
 502         kfree(header_buf);
 503         return message;
 504 }
 505
 506 static int __initdata do_retain_initrd;
 507
 508 static int __init retain_initrd_param(char *str)
 509 {
 510         if (*str)
 511                 return 0;
 512         do_retain_initrd = 1;
 513         return 1;
 514 }
 515 __setup("retain_initrd", retain_initrd_param);
 516
 517 #ifdef CONFIG_ARCH_HAS_KEEPINITRD
 518 static int __init keepinitrd_setup(char *__unused)
 519 {
 520         do_retain_initrd = 1;
 521         return 1;
 522 }
 523 __setup("keepinitrd", keepinitrd_setup);
 524 #endif
 525
 526 extern char __initramfs_start[];
 527 extern unsigned long __initramfs_size;
 528 #include <linux/initrd.h>
 529 #include <linux/kexec.h>
 530
 531 void __weak free_initrd_mem(unsigned long start, unsigned long end)
 532 {
 533 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 534         unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
 535         unsigned long aligned_end = ALIGN(end, PAGE_SIZE);
 536
 537         memblock_free(__pa(aligned_start), aligned_end - aligned_start);
 538 #endif
 539
 540         free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 541                         "initrd");
 542 }
 543
 544 #ifdef CONFIG_KEXEC_CORE
 545 static bool __init kexec_free_initrd(void)
 546 {
 547         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 548         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 549
 550         /*
 551          * If the initrd region is overlapped with crashkernel reserved region,
 552          * free only memory that is not part of crashkernel region.
 553          */
 554         if (initrd_start >= crashk_end || initrd_end <= crashk_start)
 555                 return false;
 556
 557         /*
 558          * Initialize initrd memory region since the kexec boot does not do.
 559          */
 560         memset((void *)initrd_start, 0, initrd_end - initrd_start);
 561         if (initrd_start < crashk_start)
 562                 free_initrd_mem(initrd_start, crashk_start);
 563         if (initrd_end > crashk_end)
 564                 free_initrd_mem(crashk_end, initrd_end);
 565         return true;
 566 }
 567 #else
 568 static inline bool kexec_free_initrd(void)
 569 {
 570         return false;
 571 }
 572 #endif /* CONFIG_KEXEC_CORE */
 573
 574 #ifdef CONFIG_BLK_DEV_RAM
 575 #define BUF_SIZE 1024
 576 static void __init clean_rootfs(void)
 577 {
 578         int fd;
 579         void *buf;
 580         struct linux_dirent64 *dirp;
 581         int num;
 582
 583         fd = ksys_open("/", O_RDONLY, 0);
 584         WARN_ON(fd < 0);
 585         if (fd < 0)
 586                 return;
 587         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 588         WARN_ON(!buf);
 589         if (!buf) {
 590                 ksys_close(fd);
 591                 return;
 592         }
 593
 594         dirp = buf;
 595         num = ksys_getdents64(fd, dirp, BUF_SIZE);
 596         while (num > 0) {
 597                 while (num > 0) {
 598                         struct kstat st;
 599                         int ret;
 600
 601                         ret = vfs_lstat(dirp->d_name, &st);
 602                         WARN_ON_ONCE(ret);
 603                         if (!ret) {
 604                                 if (S_ISDIR(st.mode))
 605                                         ksys_rmdir(dirp->d_name);
 606                                 else
 607                                         ksys_unlink(dirp->d_name);
 608                         }
 609
 610                         num -= dirp->d_reclen;
 611                         dirp = (void *)dirp + dirp->d_reclen;
 612                 }
 613                 dirp = buf;
 614                 memset(buf, 0, BUF_SIZE);
 615                 num = ksys_getdents64(fd, dirp, BUF_SIZE);
 616         }
 617
 618         ksys_close(fd);
 619         kfree(buf);
 620 }
 621 #else
 622 static inline void clean_rootfs(void)
 623 {
 624 }
 625 #endif /* CONFIG_BLK_DEV_RAM */
 626
 627 #ifdef CONFIG_BLK_DEV_RAM
 628 static void __init populate_initrd_image(char *err)
 629 {
 630         ssize_t written;
 631         int fd;
 632
 633         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 634
 635         printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
 636                         err);
 637         fd = ksys_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
 638         if (fd < 0)
 639                 return;
 640
 641         written = xwrite(fd, (char *)initrd_start, initrd_end - initrd_start);
 642         if (written != initrd_end - initrd_start)
 643                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 644                        written, initrd_end - initrd_start);
 645         ksys_close(fd);
 646 }
 647 #else
 648 static void __init populate_initrd_image(char *err)
 649 {
 650         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 651 }
 652 #endif /* CONFIG_BLK_DEV_RAM */
 653
 654 static int __init populate_rootfs(void)
 655 {
 656         /* Load the built in initramfs */
 657         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 658         if (err)
 659                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 660
 661         if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
 662                 goto done;
 663
 664         if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
 665                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 666         else
 667                 printk(KERN_INFO "Unpacking initramfs...\n");
 668
 669         err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
 670         if (err) {
 671                 clean_rootfs();
 672                 populate_initrd_image(err);
 673         }
 674
 675 done:
 676         /*
 677          * If the initrd region is overlapped with crashkernel reserved region,
 678          * free only memory that is not part of crashkernel region.
 679          */
 680         if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
 681                 free_initrd_mem(initrd_start, initrd_end);
 682         initrd_start = 0;
 683         initrd_end = 0;
 684
 685         flush_delayed_fput();
 686         return 0;
 687 }
 688 rootfs_initcall(populate_rootfs);