linux/fs/binfmt_flat.c
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   1/****************************************************************************/
   2/*
   3 *  linux/fs/binfmt_flat.c
   4 *
   5 *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
   6 *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
   7 *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
   8 *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
   9 *  based heavily on:
  10 *
  11 *  linux/fs/binfmt_aout.c:
  12 *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
  13 *  linux/fs/binfmt_flat.c for 2.0 kernel
  14 *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
  15 *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
  16 */
  17
  18#include <linux/export.h>
  19#include <linux/kernel.h>
  20#include <linux/sched.h>
  21#include <linux/mm.h>
  22#include <linux/mman.h>
  23#include <linux/errno.h>
  24#include <linux/signal.h>
  25#include <linux/string.h>
  26#include <linux/fs.h>
  27#include <linux/file.h>
  28#include <linux/stat.h>
  29#include <linux/fcntl.h>
  30#include <linux/ptrace.h>
  31#include <linux/user.h>
  32#include <linux/slab.h>
  33#include <linux/binfmts.h>
  34#include <linux/personality.h>
  35#include <linux/init.h>
  36#include <linux/flat.h>
  37#include <linux/syscalls.h>
  38
  39#include <asm/byteorder.h>
  40#include <asm/uaccess.h>
  41#include <asm/unaligned.h>
  42#include <asm/cacheflush.h>
  43#include <asm/page.h>
  44
  45/****************************************************************************/
  46
  47#if 0
  48#define DEBUG 1
  49#endif
  50
  51#ifdef DEBUG
  52#define DBG_FLT(a...)   printk(a)
  53#else
  54#define DBG_FLT(a...)
  55#endif
  56
  57/*
  58 * User data (data section and bss) needs to be aligned.
  59 * We pick 0x20 here because it is the max value elf2flt has always
  60 * used in producing FLAT files, and because it seems to be large
  61 * enough to make all the gcc alignment related tests happy.
  62 */
  63#define FLAT_DATA_ALIGN (0x20)
  64
  65/*
  66 * User data (stack) also needs to be aligned.
  67 * Here we can be a bit looser than the data sections since this
  68 * needs to only meet arch ABI requirements.
  69 */
  70#define FLAT_STACK_ALIGN        max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
  71
  72#define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  73#define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  74
  75struct lib_info {
  76        struct {
  77                unsigned long start_code;               /* Start of text segment */
  78                unsigned long start_data;               /* Start of data segment */
  79                unsigned long start_brk;                /* End of data segment */
  80                unsigned long text_len;                 /* Length of text segment */
  81                unsigned long entry;                    /* Start address for this module */
  82                unsigned long build_date;               /* When this one was compiled */
  83                short loaded;                           /* Has this library been loaded? */
  84        } lib_list[MAX_SHARED_LIBS];
  85};
  86
  87#ifdef CONFIG_BINFMT_SHARED_FLAT
  88static int load_flat_shared_library(int id, struct lib_info *p);
  89#endif
  90
  91static int load_flat_binary(struct linux_binprm *);
  92static int flat_core_dump(struct coredump_params *cprm);
  93
  94static struct linux_binfmt flat_format = {
  95        .module         = THIS_MODULE,
  96        .load_binary    = load_flat_binary,
  97        .core_dump      = flat_core_dump,
  98        .min_coredump   = PAGE_SIZE
  99};
 100
 101/****************************************************************************/
 102/*
 103 * Routine writes a core dump image in the current directory.
 104 * Currently only a stub-function.
 105 */
 106
 107static int flat_core_dump(struct coredump_params *cprm)
 108{
 109        printk("Process %s:%d received signr %d and should have core dumped\n",
 110                        current->comm, current->pid, (int) cprm->siginfo->si_signo);
 111        return(1);
 112}
 113
 114/****************************************************************************/
 115/*
 116 * create_flat_tables() parses the env- and arg-strings in new user
 117 * memory and creates the pointer tables from them, and puts their
 118 * addresses on the "stack", returning the new stack pointer value.
 119 */
 120
 121static unsigned long create_flat_tables(
 122        unsigned long pp,
 123        struct linux_binprm * bprm)
 124{
 125        unsigned long *argv,*envp;
 126        unsigned long * sp;
 127        char * p = (char*)pp;
 128        int argc = bprm->argc;
 129        int envc = bprm->envc;
 130        char uninitialized_var(dummy);
 131
 132        sp = (unsigned long *)p;
 133        sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
 134        sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN);
 135        argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
 136        envp = argv + (argc + 1);
 137
 138        if (flat_argvp_envp_on_stack()) {
 139                put_user((unsigned long) envp, sp + 2);
 140                put_user((unsigned long) argv, sp + 1);
 141        }
 142
 143        put_user(argc, sp);
 144        current->mm->arg_start = (unsigned long) p;
 145        while (argc-->0) {
 146                put_user((unsigned long) p, argv++);
 147                do {
 148                        get_user(dummy, p); p++;
 149                } while (dummy);
 150        }
 151        put_user((unsigned long) NULL, argv);
 152        current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 153        while (envc-->0) {
 154                put_user((unsigned long)p, envp); envp++;
 155                do {
 156                        get_user(dummy, p); p++;
 157                } while (dummy);
 158        }
 159        put_user((unsigned long) NULL, envp);
 160        current->mm->env_end = (unsigned long) p;
 161        return (unsigned long)sp;
 162}
 163
 164/****************************************************************************/
 165
 166#ifdef CONFIG_BINFMT_ZFLAT
 167
 168#include <linux/zlib.h>
 169
 170#define LBUFSIZE        4000
 171
 172/* gzip flag byte */
 173#define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 174#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 175#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 176#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 177#define COMMENT      0x10 /* bit 4 set: file comment present */
 178#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 179#define RESERVED     0xC0 /* bit 6,7:   reserved */
 180
 181static int decompress_exec(
 182        struct linux_binprm *bprm,
 183        unsigned long offset,
 184        char *dst,
 185        long len,
 186        int fd)
 187{
 188        unsigned char *buf;
 189        z_stream strm;
 190        loff_t fpos;
 191        int ret, retval;
 192
 193        DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 194
 195        memset(&strm, 0, sizeof(strm));
 196        strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 197        if (strm.workspace == NULL) {
 198                DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 199                return -ENOMEM;
 200        }
 201        buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 202        if (buf == NULL) {
 203                DBG_FLT("binfmt_flat: no memory for read buffer\n");
 204                retval = -ENOMEM;
 205                goto out_free;
 206        }
 207
 208        /* Read in first chunk of data and parse gzip header. */
 209        fpos = offset;
 210        ret = kernel_read(bprm->file, offset, buf, LBUFSIZE);
 211
 212        strm.next_in = buf;
 213        strm.avail_in = ret;
 214        strm.total_in = 0;
 215        fpos += ret;
 216
 217        retval = -ENOEXEC;
 218
 219        /* Check minimum size -- gzip header */
 220        if (ret < 10) {
 221                DBG_FLT("binfmt_flat: file too small?\n");
 222                goto out_free_buf;
 223        }
 224
 225        /* Check gzip magic number */
 226        if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 227                DBG_FLT("binfmt_flat: unknown compression magic?\n");
 228                goto out_free_buf;
 229        }
 230
 231        /* Check gzip method */
 232        if (buf[2] != 8) {
 233                DBG_FLT("binfmt_flat: unknown compression method?\n");
 234                goto out_free_buf;
 235        }
 236        /* Check gzip flags */
 237        if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 238            (buf[3] & RESERVED)) {
 239                DBG_FLT("binfmt_flat: unknown flags?\n");
 240                goto out_free_buf;
 241        }
 242
 243        ret = 10;
 244        if (buf[3] & EXTRA_FIELD) {
 245                ret += 2 + buf[10] + (buf[11] << 8);
 246                if (unlikely(LBUFSIZE <= ret)) {
 247                        DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 248                        goto out_free_buf;
 249                }
 250        }
 251        if (buf[3] & ORIG_NAME) {
 252                while (ret < LBUFSIZE && buf[ret++] != 0)
 253                        ;
 254                if (unlikely(LBUFSIZE == ret)) {
 255                        DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 256                        goto out_free_buf;
 257                }
 258        }
 259        if (buf[3] & COMMENT) {
 260                while (ret < LBUFSIZE && buf[ret++] != 0)
 261                        ;
 262                if (unlikely(LBUFSIZE == ret)) {
 263                        DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 264                        goto out_free_buf;
 265                }
 266        }
 267
 268        strm.next_in += ret;
 269        strm.avail_in -= ret;
 270
 271        strm.next_out = dst;
 272        strm.avail_out = len;
 273        strm.total_out = 0;
 274
 275        if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 276                DBG_FLT("binfmt_flat: zlib init failed?\n");
 277                goto out_free_buf;
 278        }
 279
 280        while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 281                ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE);
 282                if (ret <= 0)
 283                        break;
 284                len -= ret;
 285
 286                strm.next_in = buf;
 287                strm.avail_in = ret;
 288                strm.total_in = 0;
 289                fpos += ret;
 290        }
 291
 292        if (ret < 0) {
 293                DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 294                        ret, strm.msg);
 295                goto out_zlib;
 296        }
 297
 298        retval = 0;
 299out_zlib:
 300        zlib_inflateEnd(&strm);
 301out_free_buf:
 302        kfree(buf);
 303out_free:
 304        kfree(strm.workspace);
 305        return retval;
 306}
 307
 308#endif /* CONFIG_BINFMT_ZFLAT */
 309
 310/****************************************************************************/
 311
 312static unsigned long
 313calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
 314{
 315        unsigned long addr;
 316        int id;
 317        unsigned long start_brk;
 318        unsigned long start_data;
 319        unsigned long text_len;
 320        unsigned long start_code;
 321
 322#ifdef CONFIG_BINFMT_SHARED_FLAT
 323        if (r == 0)
 324                id = curid;     /* Relocs of 0 are always self referring */
 325        else {
 326                id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 327                r &= 0x00ffffff;        /* Trim ID off here */
 328        }
 329        if (id >= MAX_SHARED_LIBS) {
 330                printk("BINFMT_FLAT: reference 0x%x to shared library %d",
 331                                (unsigned) r, id);
 332                goto failed;
 333        }
 334        if (curid != id) {
 335                if (internalp) {
 336                        printk("BINFMT_FLAT: reloc address 0x%x not in same module "
 337                                        "(%d != %d)", (unsigned) r, curid, id);
 338                        goto failed;
 339                } else if ( ! p->lib_list[id].loaded &&
 340                                IS_ERR_VALUE(load_flat_shared_library(id, p))) {
 341                        printk("BINFMT_FLAT: failed to load library %d", id);
 342                        goto failed;
 343                }
 344                /* Check versioning information (i.e. time stamps) */
 345                if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
 346                                p->lib_list[curid].build_date < p->lib_list[id].build_date) {
 347                        printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
 348                        goto failed;
 349                }
 350        }
 351#else
 352        id = 0;
 353#endif
 354
 355        start_brk = p->lib_list[id].start_brk;
 356        start_data = p->lib_list[id].start_data;
 357        start_code = p->lib_list[id].start_code;
 358        text_len = p->lib_list[id].text_len;
 359
 360        if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 361                printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
 362                       (int) r,(int)(start_brk-start_data+text_len),(int)text_len);
 363                goto failed;
 364        }
 365
 366        if (r < text_len)                       /* In text segment */
 367                addr = r + start_code;
 368        else                                    /* In data segment */
 369                addr = r - text_len + start_data;
 370
 371        /* Range checked already above so doing the range tests is redundant...*/
 372        return(addr);
 373
 374failed:
 375        printk(", killing %s!\n", current->comm);
 376        send_sig(SIGSEGV, current, 0);
 377
 378        return RELOC_FAILED;
 379}
 380
 381/****************************************************************************/
 382
 383void old_reloc(unsigned long rl)
 384{
 385#ifdef DEBUG
 386        char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 387#endif
 388        flat_v2_reloc_t r;
 389        unsigned long *ptr;
 390        
 391        r.value = rl;
 392#if defined(CONFIG_COLDFIRE)
 393        ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
 394#else
 395        ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
 396#endif
 397
 398#ifdef DEBUG
 399        printk("Relocation of variable at DATASEG+%x "
 400                "(address %p, currently %x) into segment %s\n",
 401                r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
 402#endif
 403        
 404        switch (r.reloc.type) {
 405        case OLD_FLAT_RELOC_TYPE_TEXT:
 406                *ptr += current->mm->start_code;
 407                break;
 408        case OLD_FLAT_RELOC_TYPE_DATA:
 409                *ptr += current->mm->start_data;
 410                break;
 411        case OLD_FLAT_RELOC_TYPE_BSS:
 412                *ptr += current->mm->end_data;
 413                break;
 414        default:
 415                printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
 416                break;
 417        }
 418
 419#ifdef DEBUG
 420        printk("Relocation became %x\n", (int)*ptr);
 421#endif
 422}               
 423
 424/****************************************************************************/
 425
 426static int load_flat_file(struct linux_binprm * bprm,
 427                struct lib_info *libinfo, int id, unsigned long *extra_stack)
 428{
 429        struct flat_hdr * hdr;
 430        unsigned long textpos = 0, datapos = 0, result;
 431        unsigned long realdatastart = 0;
 432        unsigned long text_len, data_len, bss_len, stack_len, flags;
 433        unsigned long full_data;
 434        unsigned long len, memp = 0;
 435        unsigned long memp_size, extra, rlim;
 436        unsigned long *reloc = 0, *rp;
 437        struct inode *inode;
 438        int i, rev, relocs = 0;
 439        loff_t fpos;
 440        unsigned long start_code, end_code;
 441        int ret;
 442
 443        hdr = ((struct flat_hdr *) bprm->buf);          /* exec-header */
 444        inode = file_inode(bprm->file);
 445
 446        text_len  = ntohl(hdr->data_start);
 447        data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 448        bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 449        stack_len = ntohl(hdr->stack_size);
 450        if (extra_stack) {
 451                stack_len += *extra_stack;
 452                *extra_stack = stack_len;
 453        }
 454        relocs    = ntohl(hdr->reloc_count);
 455        flags     = ntohl(hdr->flags);
 456        rev       = ntohl(hdr->rev);
 457        full_data = data_len + relocs * sizeof(unsigned long);
 458
 459        if (strncmp(hdr->magic, "bFLT", 4)) {
 460                /*
 461                 * Previously, here was a printk to tell people
 462                 *   "BINFMT_FLAT: bad header magic".
 463                 * But for the kernel which also use ELF FD-PIC format, this
 464                 * error message is confusing.
 465                 * because a lot of people do not manage to produce good
 466                 */
 467                ret = -ENOEXEC;
 468                goto err;
 469        }
 470
 471        if (flags & FLAT_FLAG_KTRACE)
 472                printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 473
 474        if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 475                printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
 476                        "0x%lx and 0x%lx)\n",
 477                        rev, FLAT_VERSION, OLD_FLAT_VERSION);
 478                ret = -ENOEXEC;
 479                goto err;
 480        }
 481        
 482        /* Don't allow old format executables to use shared libraries */
 483        if (rev == OLD_FLAT_VERSION && id != 0) {
 484                printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
 485                                (int) FLAT_VERSION);
 486                ret = -ENOEXEC;
 487                goto err;
 488        }
 489
 490        /*
 491         * fix up the flags for the older format,  there were all kinds
 492         * of endian hacks,  this only works for the simple cases
 493         */
 494        if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 495                flags = FLAT_FLAG_RAM;
 496
 497#ifndef CONFIG_BINFMT_ZFLAT
 498        if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 499                printk("Support for ZFLAT executables is not enabled.\n");
 500                ret = -ENOEXEC;
 501                goto err;
 502        }
 503#endif
 504
 505        /*
 506         * Check initial limits. This avoids letting people circumvent
 507         * size limits imposed on them by creating programs with large
 508         * arrays in the data or bss.
 509         */
 510        rlim = rlimit(RLIMIT_DATA);
 511        if (rlim >= RLIM_INFINITY)
 512                rlim = ~0;
 513        if (data_len + bss_len > rlim) {
 514                ret = -ENOMEM;
 515                goto err;
 516        }
 517
 518        /* Flush all traces of the currently running executable */
 519        if (id == 0) {
 520                result = flush_old_exec(bprm);
 521                if (result) {
 522                        ret = result;
 523                        goto err;
 524                }
 525
 526                /* OK, This is the point of no return */
 527                set_personality(PER_LINUX_32BIT);
 528                setup_new_exec(bprm);
 529        }
 530
 531        /*
 532         * calculate the extra space we need to map in
 533         */
 534        extra = max_t(unsigned long, bss_len + stack_len,
 535                        relocs * sizeof(unsigned long));
 536
 537        /*
 538         * there are a couple of cases here,  the separate code/data
 539         * case,  and then the fully copied to RAM case which lumps
 540         * it all together.
 541         */
 542        if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 543                /*
 544                 * this should give us a ROM ptr,  but if it doesn't we don't
 545                 * really care
 546                 */
 547                DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 548
 549                textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
 550                                  MAP_PRIVATE|MAP_EXECUTABLE, 0);
 551                if (!textpos || IS_ERR_VALUE(textpos)) {
 552                        if (!textpos)
 553                                textpos = (unsigned long) -ENOMEM;
 554                        printk("Unable to mmap process text, errno %d\n", (int)-textpos);
 555                        ret = textpos;
 556                        goto err;
 557                }
 558
 559                len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
 560                len = PAGE_ALIGN(len);
 561                realdatastart = vm_mmap(0, 0, len,
 562                        PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
 563
 564                if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
 565                        if (!realdatastart)
 566                                realdatastart = (unsigned long) -ENOMEM;
 567                        printk("Unable to allocate RAM for process data, errno %d\n",
 568                                        (int)-realdatastart);
 569                        vm_munmap(textpos, text_len);
 570                        ret = realdatastart;
 571                        goto err;
 572                }
 573                datapos = ALIGN(realdatastart +
 574                                MAX_SHARED_LIBS * sizeof(unsigned long),
 575                                FLAT_DATA_ALIGN);
 576
 577                DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 578                                (int)(data_len + bss_len + stack_len), (int)datapos);
 579
 580                fpos = ntohl(hdr->data_start);
 581#ifdef CONFIG_BINFMT_ZFLAT
 582                if (flags & FLAT_FLAG_GZDATA) {
 583                        result = decompress_exec(bprm, fpos, (char *) datapos, 
 584                                                 full_data, 0);
 585                } else
 586#endif
 587                {
 588                        result = read_code(bprm->file, datapos, fpos,
 589                                        full_data);
 590                }
 591                if (IS_ERR_VALUE(result)) {
 592                        printk("Unable to read data+bss, errno %d\n", (int)-result);
 593                        vm_munmap(textpos, text_len);
 594                        vm_munmap(realdatastart, len);
 595                        ret = result;
 596                        goto err;
 597                }
 598
 599                reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
 600                memp = realdatastart;
 601                memp_size = len;
 602        } else {
 603
 604                len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
 605                len = PAGE_ALIGN(len);
 606                textpos = vm_mmap(0, 0, len,
 607                        PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
 608
 609                if (!textpos || IS_ERR_VALUE(textpos)) {
 610                        if (!textpos)
 611                                textpos = (unsigned long) -ENOMEM;
 612                        printk("Unable to allocate RAM for process text/data, errno %d\n",
 613                                        (int)-textpos);
 614                        ret = textpos;
 615                        goto err;
 616                }
 617
 618                realdatastart = textpos + ntohl(hdr->data_start);
 619                datapos = ALIGN(realdatastart +
 620                                MAX_SHARED_LIBS * sizeof(unsigned long),
 621                                FLAT_DATA_ALIGN);
 622
 623                reloc = (unsigned long *)
 624                        (datapos + (ntohl(hdr->reloc_start) - text_len));
 625                memp = textpos;
 626                memp_size = len;
 627#ifdef CONFIG_BINFMT_ZFLAT
 628                /*
 629                 * load it all in and treat it like a RAM load from now on
 630                 */
 631                if (flags & FLAT_FLAG_GZIP) {
 632                        result = decompress_exec(bprm, sizeof (struct flat_hdr),
 633                                         (((char *) textpos) + sizeof (struct flat_hdr)),
 634                                         (text_len + full_data
 635                                                  - sizeof (struct flat_hdr)),
 636                                         0);
 637                        memmove((void *) datapos, (void *) realdatastart,
 638                                        full_data);
 639                } else if (flags & FLAT_FLAG_GZDATA) {
 640                        result = read_code(bprm->file, textpos, 0, text_len);
 641                        if (!IS_ERR_VALUE(result))
 642                                result = decompress_exec(bprm, text_len, (char *) datapos,
 643                                                 full_data, 0);
 644                }
 645                else
 646#endif
 647                {
 648                        result = read_code(bprm->file, textpos, 0, text_len);
 649                        if (!IS_ERR_VALUE(result))
 650                                result = read_code(bprm->file, datapos,
 651                                                   ntohl(hdr->data_start),
 652                                                   full_data);
 653                }
 654                if (IS_ERR_VALUE(result)) {
 655                        printk("Unable to read code+data+bss, errno %d\n",(int)-result);
 656                        vm_munmap(textpos, text_len + data_len + extra +
 657                                MAX_SHARED_LIBS * sizeof(unsigned long));
 658                        ret = result;
 659                        goto err;
 660                }
 661        }
 662
 663        if (flags & FLAT_FLAG_KTRACE)
 664                printk("Mapping is %x, Entry point is %x, data_start is %x\n",
 665                        (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
 666
 667        /* The main program needs a little extra setup in the task structure */
 668        start_code = textpos + sizeof (struct flat_hdr);
 669        end_code = textpos + text_len;
 670        if (id == 0) {
 671                current->mm->start_code = start_code;
 672                current->mm->end_code = end_code;
 673                current->mm->start_data = datapos;
 674                current->mm->end_data = datapos + data_len;
 675                /*
 676                 * set up the brk stuff, uses any slack left in data/bss/stack
 677                 * allocation.  We put the brk after the bss (between the bss
 678                 * and stack) like other platforms.
 679                 * Userspace code relies on the stack pointer starting out at
 680                 * an address right at the end of a page.
 681                 */
 682                current->mm->start_brk = datapos + data_len + bss_len;
 683                current->mm->brk = (current->mm->start_brk + 3) & ~3;
 684                current->mm->context.end_brk = memp + memp_size - stack_len;
 685        }
 686
 687        if (flags & FLAT_FLAG_KTRACE)
 688                printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 689                        id ? "Lib" : "Load", bprm->filename,
 690                        (int) start_code, (int) end_code,
 691                        (int) datapos,
 692                        (int) (datapos + data_len),
 693                        (int) (datapos + data_len),
 694                        (int) (((datapos + data_len + bss_len) + 3) & ~3));
 695
 696        text_len -= sizeof(struct flat_hdr); /* the real code len */
 697
 698        /* Store the current module values into the global library structure */
 699        libinfo->lib_list[id].start_code = start_code;
 700        libinfo->lib_list[id].start_data = datapos;
 701        libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
 702        libinfo->lib_list[id].text_len = text_len;
 703        libinfo->lib_list[id].loaded = 1;
 704        libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 705        libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
 706        
 707        /*
 708         * We just load the allocations into some temporary memory to
 709         * help simplify all this mumbo jumbo
 710         *
 711         * We've got two different sections of relocation entries.
 712         * The first is the GOT which resides at the beginning of the data segment
 713         * and is terminated with a -1.  This one can be relocated in place.
 714         * The second is the extra relocation entries tacked after the image's
 715         * data segment. These require a little more processing as the entry is
 716         * really an offset into the image which contains an offset into the
 717         * image.
 718         */
 719        if (flags & FLAT_FLAG_GOTPIC) {
 720                for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
 721                        unsigned long addr;
 722                        if (*rp) {
 723                                addr = calc_reloc(*rp, libinfo, id, 0);
 724                                if (addr == RELOC_FAILED) {
 725                                        ret = -ENOEXEC;
 726                                        goto err;
 727                                }
 728                                *rp = addr;
 729                        }
 730                }
 731        }
 732
 733        /*
 734         * Now run through the relocation entries.
 735         * We've got to be careful here as C++ produces relocatable zero
 736         * entries in the constructor and destructor tables which are then
 737         * tested for being not zero (which will always occur unless we're
 738         * based from address zero).  This causes an endless loop as __start
 739         * is at zero.  The solution used is to not relocate zero addresses.
 740         * This has the negative side effect of not allowing a global data
 741         * reference to be statically initialised to _stext (I've moved
 742         * __start to address 4 so that is okay).
 743         */
 744        if (rev > OLD_FLAT_VERSION) {
 745                unsigned long persistent = 0;
 746                for (i=0; i < relocs; i++) {
 747                        unsigned long addr, relval;
 748
 749                        /* Get the address of the pointer to be
 750                           relocated (of course, the address has to be
 751                           relocated first).  */
 752                        relval = ntohl(reloc[i]);
 753                        if (flat_set_persistent (relval, &persistent))
 754                                continue;
 755                        addr = flat_get_relocate_addr(relval);
 756                        rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
 757                        if (rp == (unsigned long *)RELOC_FAILED) {
 758                                ret = -ENOEXEC;
 759                                goto err;
 760                        }
 761
 762                        /* Get the pointer's value.  */
 763                        addr = flat_get_addr_from_rp(rp, relval, flags,
 764                                                        &persistent);
 765                        if (addr != 0) {
 766                                /*
 767                                 * Do the relocation.  PIC relocs in the data section are
 768                                 * already in target order
 769                                 */
 770                                if ((flags & FLAT_FLAG_GOTPIC) == 0)
 771                                        addr = ntohl(addr);
 772                                addr = calc_reloc(addr, libinfo, id, 0);
 773                                if (addr == RELOC_FAILED) {
 774                                        ret = -ENOEXEC;
 775                                        goto err;
 776                                }
 777
 778                                /* Write back the relocated pointer.  */
 779                                flat_put_addr_at_rp(rp, addr, relval);
 780                        }
 781                }
 782        } else {
 783                for (i=0; i < relocs; i++)
 784                        old_reloc(ntohl(reloc[i]));
 785        }
 786        
 787        flush_icache_range(start_code, end_code);
 788
 789        /* zero the BSS,  BRK and stack areas */
 790        memset((void*)(datapos + data_len), 0, bss_len + 
 791                        (memp + memp_size - stack_len -         /* end brk */
 792                        libinfo->lib_list[id].start_brk) +      /* start brk */
 793                        stack_len);
 794
 795        return 0;
 796err:
 797        return ret;
 798}
 799
 800
 801/****************************************************************************/
 802#ifdef CONFIG_BINFMT_SHARED_FLAT
 803
 804/*
 805 * Load a shared library into memory.  The library gets its own data
 806 * segment (including bss) but not argv/argc/environ.
 807 */
 808
 809static int load_flat_shared_library(int id, struct lib_info *libs)
 810{
 811        struct linux_binprm bprm;
 812        int res;
 813        char buf[16];
 814
 815        memset(&bprm, 0, sizeof(bprm));
 816
 817        /* Create the file name */
 818        sprintf(buf, "/lib/lib%d.so", id);
 819
 820        /* Open the file up */
 821        bprm.filename = buf;
 822        bprm.file = open_exec(bprm.filename);
 823        res = PTR_ERR(bprm.file);
 824        if (IS_ERR(bprm.file))
 825                return res;
 826
 827        bprm.cred = prepare_exec_creds();
 828        res = -ENOMEM;
 829        if (!bprm.cred)
 830                goto out;
 831
 832        /* We don't really care about recalculating credentials at this point
 833         * as we're past the point of no return and are dealing with shared
 834         * libraries.
 835         */
 836        bprm.cred_prepared = 1;
 837
 838        res = prepare_binprm(&bprm);
 839
 840        if (!IS_ERR_VALUE(res))
 841                res = load_flat_file(&bprm, libs, id, NULL);
 842
 843        abort_creds(bprm.cred);
 844
 845out:
 846        allow_write_access(bprm.file);
 847        fput(bprm.file);
 848
 849        return(res);
 850}
 851
 852#endif /* CONFIG_BINFMT_SHARED_FLAT */
 853/****************************************************************************/
 854
 855/*
 856 * These are the functions used to load flat style executables and shared
 857 * libraries.  There is no binary dependent code anywhere else.
 858 */
 859
 860static int load_flat_binary(struct linux_binprm * bprm)
 861{
 862        struct lib_info libinfo;
 863        struct pt_regs *regs = current_pt_regs();
 864        unsigned long p = bprm->p;
 865        unsigned long stack_len;
 866        unsigned long start_addr;
 867        unsigned long *sp;
 868        int res;
 869        int i, j;
 870
 871        memset(&libinfo, 0, sizeof(libinfo));
 872        /*
 873         * We have to add the size of our arguments to our stack size
 874         * otherwise it's too easy for users to create stack overflows
 875         * by passing in a huge argument list.  And yes,  we have to be
 876         * pedantic and include space for the argv/envp array as it may have
 877         * a lot of entries.
 878         */
 879#define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
 880        stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
 881        stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
 882        stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
 883        stack_len += FLAT_STACK_ALIGN - 1;  /* reserve for upcoming alignment */
 884        
 885        res = load_flat_file(bprm, &libinfo, 0, &stack_len);
 886        if (IS_ERR_VALUE(res))
 887                return res;
 888        
 889        /* Update data segment pointers for all libraries */
 890        for (i=0; i<MAX_SHARED_LIBS; i++)
 891                if (libinfo.lib_list[i].loaded)
 892                        for (j=0; j<MAX_SHARED_LIBS; j++)
 893                                (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
 894                                        (libinfo.lib_list[j].loaded)?
 895                                                libinfo.lib_list[j].start_data:UNLOADED_LIB;
 896
 897        install_exec_creds(bprm);
 898
 899        set_binfmt(&flat_format);
 900
 901        p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
 902        DBG_FLT("p=%x\n", (int)p);
 903
 904        /* copy the arg pages onto the stack, this could be more efficient :-) */
 905        for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
 906                * (char *) --p =
 907                        ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
 908
 909        sp = (unsigned long *) create_flat_tables(p, bprm);
 910        
 911        /* Fake some return addresses to ensure the call chain will
 912         * initialise library in order for us.  We are required to call
 913         * lib 1 first, then 2, ... and finally the main program (id 0).
 914         */
 915        start_addr = libinfo.lib_list[0].entry;
 916
 917#ifdef CONFIG_BINFMT_SHARED_FLAT
 918        for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 919                if (libinfo.lib_list[i].loaded) {
 920                        /* Push previos first to call address */
 921                        --sp;   put_user(start_addr, sp);
 922                        start_addr = libinfo.lib_list[i].entry;
 923                }
 924        }
 925#endif
 926        
 927        /* Stash our initial stack pointer into the mm structure */
 928        current->mm->start_stack = (unsigned long )sp;
 929
 930#ifdef FLAT_PLAT_INIT
 931        FLAT_PLAT_INIT(regs);
 932#endif
 933        DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
 934                (int)regs, (int)start_addr, (int)current->mm->start_stack);
 935        
 936        start_thread(regs, start_addr, current->mm->start_stack);
 937
 938        return 0;
 939}
 940
 941/****************************************************************************/
 942
 943static int __init init_flat_binfmt(void)
 944{
 945        register_binfmt(&flat_format);
 946        return 0;
 947}
 948
 949/****************************************************************************/
 950
 951core_initcall(init_flat_binfmt);
 952
 953/****************************************************************************/
 954
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