linux/init/initramfs.c
<<
>>
Prefs
   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#include <linux/file.h>
  22
  23static ssize_t __init xwrite(int fd, const char *p, size_t count)
  24{
  25        ssize_t out = 0;
  26
  27        /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  28        while (count) {
  29                ssize_t rv = sys_write(fd, p, count);
  30
  31                if (rv < 0) {
  32                        if (rv == -EINTR || rv == -EAGAIN)
  33                                continue;
  34                        return out ? out : rv;
  35                } else if (rv == 0)
  36                        break;
  37
  38                p += rv;
  39                out += rv;
  40                count -= rv;
  41        }
  42
  43        return out;
  44}
  45
  46static __initdata char *message;
  47static void __init error(char *x)
  48{
  49        if (!message)
  50                message = x;
  51}
  52
  53/* link hash */
  54
  55#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  56
  57static __initdata struct hash {
  58        int ino, minor, major;
  59        umode_t mode;
  60        struct hash *next;
  61        char name[N_ALIGN(PATH_MAX)];
  62} *head[32];
  63
  64static inline int hash(int major, int minor, int ino)
  65{
  66        unsigned long tmp = ino + minor + (major << 3);
  67        tmp += tmp >> 5;
  68        return tmp & 31;
  69}
  70
  71static char __init *find_link(int major, int minor, int ino,
  72                              umode_t mode, char *name)
  73{
  74        struct hash **p, *q;
  75        for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  76                if ((*p)->ino != ino)
  77                        continue;
  78                if ((*p)->minor != minor)
  79                        continue;
  80                if ((*p)->major != major)
  81                        continue;
  82                if (((*p)->mode ^ mode) & S_IFMT)
  83                        continue;
  84                return (*p)->name;
  85        }
  86        q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  87        if (!q)
  88                panic("can't allocate link hash entry");
  89        q->major = major;
  90        q->minor = minor;
  91        q->ino = ino;
  92        q->mode = mode;
  93        strcpy(q->name, name);
  94        q->next = NULL;
  95        *p = q;
  96        return NULL;
  97}
  98
  99static void __init free_hash(void)
 100{
 101        struct hash **p, *q;
 102        for (p = head; p < head + 32; p++) {
 103                while (*p) {
 104                        q = *p;
 105                        *p = q->next;
 106                        kfree(q);
 107                }
 108        }
 109}
 110
 111static long __init do_utime(char *filename, time_t mtime)
 112{
 113        struct timespec t[2];
 114
 115        t[0].tv_sec = mtime;
 116        t[0].tv_nsec = 0;
 117        t[1].tv_sec = mtime;
 118        t[1].tv_nsec = 0;
 119
 120        return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
 121}
 122
 123static __initdata LIST_HEAD(dir_list);
 124struct dir_entry {
 125        struct list_head list;
 126        char *name;
 127        time_t mtime;
 128};
 129
 130static void __init dir_add(const char *name, time_t mtime)
 131{
 132        struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 133        if (!de)
 134                panic("can't allocate dir_entry buffer");
 135        INIT_LIST_HEAD(&de->list);
 136        de->name = kstrdup(name, GFP_KERNEL);
 137        de->mtime = mtime;
 138        list_add(&de->list, &dir_list);
 139}
 140
 141static void __init dir_utime(void)
 142{
 143        struct dir_entry *de, *tmp;
 144        list_for_each_entry_safe(de, tmp, &dir_list, list) {
 145                list_del(&de->list);
 146                do_utime(de->name, de->mtime);
 147                kfree(de->name);
 148                kfree(de);
 149        }
 150}
 151
 152static __initdata time_t mtime;
 153
 154/* cpio header parsing */
 155
 156static __initdata unsigned long ino, major, minor, nlink;
 157static __initdata umode_t mode;
 158static __initdata unsigned long body_len, name_len;
 159static __initdata uid_t uid;
 160static __initdata gid_t gid;
 161static __initdata unsigned rdev;
 162
 163static void __init parse_header(char *s)
 164{
 165        unsigned long parsed[12];
 166        char buf[9];
 167        int i;
 168
 169        buf[8] = '\0';
 170        for (i = 0, s += 6; i < 12; i++, s += 8) {
 171                memcpy(buf, s, 8);
 172                parsed[i] = simple_strtoul(buf, NULL, 16);
 173        }
 174        ino = parsed[0];
 175        mode = parsed[1];
 176        uid = parsed[2];
 177        gid = parsed[3];
 178        nlink = parsed[4];
 179        mtime = parsed[5];
 180        body_len = parsed[6];
 181        major = parsed[7];
 182        minor = parsed[8];
 183        rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 184        name_len = parsed[11];
 185}
 186
 187/* FSM */
 188
 189static __initdata enum state {
 190        Start,
 191        Collect,
 192        GotHeader,
 193        SkipIt,
 194        GotName,
 195        CopyFile,
 196        GotSymlink,
 197        Reset
 198} state, next_state;
 199
 200static __initdata char *victim;
 201static unsigned long byte_count __initdata;
 202static __initdata loff_t this_header, next_header;
 203
 204static inline void __init eat(unsigned n)
 205{
 206        victim += n;
 207        this_header += n;
 208        byte_count -= n;
 209}
 210
 211static __initdata char *vcollected;
 212static __initdata char *collected;
 213static long remains __initdata;
 214static __initdata char *collect;
 215
 216static void __init read_into(char *buf, unsigned size, enum state next)
 217{
 218        if (byte_count >= size) {
 219                collected = victim;
 220                eat(size);
 221                state = next;
 222        } else {
 223                collect = collected = buf;
 224                remains = size;
 225                next_state = next;
 226                state = Collect;
 227        }
 228}
 229
 230static __initdata char *header_buf, *symlink_buf, *name_buf;
 231
 232static int __init do_start(void)
 233{
 234        read_into(header_buf, 110, GotHeader);
 235        return 0;
 236}
 237
 238static int __init do_collect(void)
 239{
 240        unsigned long n = remains;
 241        if (byte_count < n)
 242                n = byte_count;
 243        memcpy(collect, victim, n);
 244        eat(n);
 245        collect += n;
 246        if ((remains -= n) != 0)
 247                return 1;
 248        state = next_state;
 249        return 0;
 250}
 251
 252static int __init do_header(void)
 253{
 254        if (memcmp(collected, "070707", 6)==0) {
 255                error("incorrect cpio method used: use -H newc option");
 256                return 1;
 257        }
 258        if (memcmp(collected, "070701", 6)) {
 259                error("no cpio magic");
 260                return 1;
 261        }
 262        parse_header(collected);
 263        next_header = this_header + N_ALIGN(name_len) + body_len;
 264        next_header = (next_header + 3) & ~3;
 265        state = SkipIt;
 266        if (name_len <= 0 || name_len > PATH_MAX)
 267                return 0;
 268        if (S_ISLNK(mode)) {
 269                if (body_len > PATH_MAX)
 270                        return 0;
 271                collect = collected = symlink_buf;
 272                remains = N_ALIGN(name_len) + body_len;
 273                next_state = GotSymlink;
 274                state = Collect;
 275                return 0;
 276        }
 277        if (S_ISREG(mode) || !body_len)
 278                read_into(name_buf, N_ALIGN(name_len), GotName);
 279        return 0;
 280}
 281
 282static int __init do_skip(void)
 283{
 284        if (this_header + byte_count < next_header) {
 285                eat(byte_count);
 286                return 1;
 287        } else {
 288                eat(next_header - this_header);
 289                state = next_state;
 290                return 0;
 291        }
 292}
 293
 294static int __init do_reset(void)
 295{
 296        while (byte_count && *victim == '\0')
 297                eat(1);
 298        if (byte_count && (this_header & 3))
 299                error("broken padding");
 300        return 1;
 301}
 302
 303static int __init maybe_link(void)
 304{
 305        if (nlink >= 2) {
 306                char *old = find_link(major, minor, ino, mode, collected);
 307                if (old)
 308                        return (sys_link(old, collected) < 0) ? -1 : 1;
 309        }
 310        return 0;
 311}
 312
 313static void __init clean_path(char *path, umode_t fmode)
 314{
 315        struct stat st;
 316
 317        if (!sys_newlstat(path, &st) && (st.st_mode ^ fmode) & S_IFMT) {
 318                if (S_ISDIR(st.st_mode))
 319                        sys_rmdir(path);
 320                else
 321                        sys_unlink(path);
 322        }
 323}
 324
 325static __initdata int wfd;
 326
 327static int __init do_name(void)
 328{
 329        state = SkipIt;
 330        next_state = Reset;
 331        if (strcmp(collected, "TRAILER!!!") == 0) {
 332                free_hash();
 333                return 0;
 334        }
 335        clean_path(collected, mode);
 336        if (S_ISREG(mode)) {
 337                int ml = maybe_link();
 338                if (ml >= 0) {
 339                        int openflags = O_WRONLY|O_CREAT;
 340                        if (ml != 1)
 341                                openflags |= O_TRUNC;
 342                        wfd = sys_open(collected, openflags, mode);
 343
 344                        if (wfd >= 0) {
 345                                sys_fchown(wfd, uid, gid);
 346                                sys_fchmod(wfd, mode);
 347                                if (body_len)
 348                                        sys_ftruncate(wfd, body_len);
 349                                vcollected = kstrdup(collected, GFP_KERNEL);
 350                                state = CopyFile;
 351                        }
 352                }
 353        } else if (S_ISDIR(mode)) {
 354                sys_mkdir(collected, mode);
 355                sys_chown(collected, uid, gid);
 356                sys_chmod(collected, mode);
 357                dir_add(collected, mtime);
 358        } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 359                   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 360                if (maybe_link() == 0) {
 361                        sys_mknod(collected, mode, rdev);
 362                        sys_chown(collected, uid, gid);
 363                        sys_chmod(collected, mode);
 364                        do_utime(collected, mtime);
 365                }
 366        }
 367        return 0;
 368}
 369
 370static int __init do_copy(void)
 371{
 372        if (byte_count >= body_len) {
 373                if (xwrite(wfd, victim, body_len) != body_len)
 374                        error("write error");
 375                sys_close(wfd);
 376                do_utime(vcollected, mtime);
 377                kfree(vcollected);
 378                eat(body_len);
 379                state = SkipIt;
 380                return 0;
 381        } else {
 382                if (xwrite(wfd, victim, byte_count) != byte_count)
 383                        error("write error");
 384                body_len -= byte_count;
 385                eat(byte_count);
 386                return 1;
 387        }
 388}
 389
 390static int __init do_symlink(void)
 391{
 392        collected[N_ALIGN(name_len) + body_len] = '\0';
 393        clean_path(collected, 0);
 394        sys_symlink(collected + N_ALIGN(name_len), collected);
 395        sys_lchown(collected, uid, gid);
 396        do_utime(collected, mtime);
 397        state = SkipIt;
 398        next_state = Reset;
 399        return 0;
 400}
 401
 402static __initdata int (*actions[])(void) = {
 403        [Start]         = do_start,
 404        [Collect]       = do_collect,
 405        [GotHeader]     = do_header,
 406        [SkipIt]        = do_skip,
 407        [GotName]       = do_name,
 408        [CopyFile]      = do_copy,
 409        [GotSymlink]    = do_symlink,
 410        [Reset]         = do_reset,
 411};
 412
 413static long __init write_buffer(char *buf, unsigned long len)
 414{
 415        byte_count = len;
 416        victim = buf;
 417
 418        while (!actions[state]())
 419                ;
 420        return len - byte_count;
 421}
 422
 423static long __init flush_buffer(void *bufv, unsigned long len)
 424{
 425        char *buf = (char *) bufv;
 426        long written;
 427        long origLen = len;
 428        if (message)
 429                return -1;
 430        while ((written = write_buffer(buf, len)) < len && !message) {
 431                char c = buf[written];
 432                if (c == '0') {
 433                        buf += written;
 434                        len -= written;
 435                        state = Start;
 436                } else if (c == 0) {
 437                        buf += written;
 438                        len -= written;
 439                        state = Reset;
 440                } else
 441                        error("junk in compressed archive");
 442        }
 443        return origLen;
 444}
 445
 446static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 447
 448#include <linux/decompress/generic.h>
 449
 450static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 451{
 452        long written;
 453        decompress_fn decompress;
 454        const char *compress_name;
 455        static __initdata char msg_buf[64];
 456
 457        header_buf = kmalloc(110, GFP_KERNEL);
 458        symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 459        name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 460
 461        if (!header_buf || !symlink_buf || !name_buf)
 462                panic("can't allocate buffers");
 463
 464        state = Start;
 465        this_header = 0;
 466        message = NULL;
 467        while (!message && len) {
 468                loff_t saved_offset = this_header;
 469                if (*buf == '0' && !(this_header & 3)) {
 470                        state = Start;
 471                        written = write_buffer(buf, len);
 472                        buf += written;
 473                        len -= written;
 474                        continue;
 475                }
 476                if (!*buf) {
 477                        buf++;
 478                        len--;
 479                        this_header++;
 480                        continue;
 481                }
 482                this_header = 0;
 483                decompress = decompress_method(buf, len, &compress_name);
 484                pr_debug("Detected %s compressed data\n", compress_name);
 485                if (decompress) {
 486                        int res = decompress(buf, len, NULL, flush_buffer, NULL,
 487                                   &my_inptr, error);
 488                        if (res)
 489                                error("decompressor failed");
 490                } else if (compress_name) {
 491                        if (!message) {
 492                                snprintf(msg_buf, sizeof msg_buf,
 493                                         "compression method %s not configured",
 494                                         compress_name);
 495                                message = msg_buf;
 496                        }
 497                } else
 498                        error("junk in compressed archive");
 499                if (state != Reset)
 500                        error("junk in compressed archive");
 501                this_header = saved_offset + my_inptr;
 502                buf += my_inptr;
 503                len -= my_inptr;
 504        }
 505        dir_utime();
 506        kfree(name_buf);
 507        kfree(symlink_buf);
 508        kfree(header_buf);
 509        return message;
 510}
 511
 512static int __initdata do_retain_initrd;
 513
 514static int __init retain_initrd_param(char *str)
 515{
 516        if (*str)
 517                return 0;
 518        do_retain_initrd = 1;
 519        return 1;
 520}
 521__setup("retain_initrd", retain_initrd_param);
 522
 523extern char __initramfs_start[];
 524extern unsigned long __initramfs_size;
 525#include <linux/initrd.h>
 526#include <linux/kexec.h>
 527
 528static void __init free_initrd(void)
 529{
 530#ifdef CONFIG_KEXEC_CORE
 531        unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 532        unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 533#endif
 534        if (do_retain_initrd)
 535                goto skip;
 536
 537#ifdef CONFIG_KEXEC_CORE
 538        /*
 539         * If the initrd region is overlapped with crashkernel reserved region,
 540         * free only memory that is not part of crashkernel region.
 541         */
 542        if (initrd_start < crashk_end && initrd_end > crashk_start) {
 543                /*
 544                 * Initialize initrd memory region since the kexec boot does
 545                 * not do.
 546                 */
 547                memset((void *)initrd_start, 0, initrd_end - initrd_start);
 548                if (initrd_start < crashk_start)
 549                        free_initrd_mem(initrd_start, crashk_start);
 550                if (initrd_end > crashk_end)
 551                        free_initrd_mem(crashk_end, initrd_end);
 552        } else
 553#endif
 554                free_initrd_mem(initrd_start, initrd_end);
 555skip:
 556        initrd_start = 0;
 557        initrd_end = 0;
 558}
 559
 560#ifdef CONFIG_BLK_DEV_RAM
 561#define BUF_SIZE 1024
 562static void __init clean_rootfs(void)
 563{
 564        int fd;
 565        void *buf;
 566        struct linux_dirent64 *dirp;
 567        int num;
 568
 569        fd = sys_open("/", O_RDONLY, 0);
 570        WARN_ON(fd < 0);
 571        if (fd < 0)
 572                return;
 573        buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 574        WARN_ON(!buf);
 575        if (!buf) {
 576                sys_close(fd);
 577                return;
 578        }
 579
 580        dirp = buf;
 581        num = sys_getdents64(fd, dirp, BUF_SIZE);
 582        while (num > 0) {
 583                while (num > 0) {
 584                        struct stat st;
 585                        int ret;
 586
 587                        ret = sys_newlstat(dirp->d_name, &st);
 588                        WARN_ON_ONCE(ret);
 589                        if (!ret) {
 590                                if (S_ISDIR(st.st_mode))
 591                                        sys_rmdir(dirp->d_name);
 592                                else
 593                                        sys_unlink(dirp->d_name);
 594                        }
 595
 596                        num -= dirp->d_reclen;
 597                        dirp = (void *)dirp + dirp->d_reclen;
 598                }
 599                dirp = buf;
 600                memset(buf, 0, BUF_SIZE);
 601                num = sys_getdents64(fd, dirp, BUF_SIZE);
 602        }
 603
 604        sys_close(fd);
 605        kfree(buf);
 606}
 607#endif
 608
 609static int __init populate_rootfs(void)
 610{
 611        char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 612        if (err)
 613                panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 614        if (initrd_start) {
 615#ifdef CONFIG_BLK_DEV_RAM
 616                int fd;
 617                printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 618                err = unpack_to_rootfs((char *)initrd_start,
 619                        initrd_end - initrd_start);
 620                if (!err) {
 621                        free_initrd();
 622                        goto done;
 623                } else {
 624                        clean_rootfs();
 625                        unpack_to_rootfs(__initramfs_start, __initramfs_size);
 626                }
 627                printk(KERN_INFO "rootfs image is not initramfs (%s)"
 628                                "; looks like an initrd\n", err);
 629                fd = sys_open("/initrd.image",
 630                              O_WRONLY|O_CREAT, 0700);
 631                if (fd >= 0) {
 632                        ssize_t written = xwrite(fd, (char *)initrd_start,
 633                                                initrd_end - initrd_start);
 634
 635                        if (written != initrd_end - initrd_start)
 636                                pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 637                                       written, initrd_end - initrd_start);
 638
 639                        sys_close(fd);
 640                        free_initrd();
 641                }
 642        done:
 643#else
 644                printk(KERN_INFO "Unpacking initramfs...\n");
 645                err = unpack_to_rootfs((char *)initrd_start,
 646                        initrd_end - initrd_start);
 647                if (err)
 648                        printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 649                free_initrd();
 650#endif
 651                flush_delayed_fput();
 652                /*
 653                 * Try loading default modules from initramfs.  This gives
 654                 * us a chance to load before device_initcalls.
 655                 */
 656                load_default_modules();
 657        }
 658        return 0;
 659}
 660rootfs_initcall(populate_rootfs);
 661