linux-user/flatload.c

   1 /****************************************************************************/
   2 /*
   3  *  QEMU bFLT binary loader.  Based on linux/fs/binfmt_flat.c
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  *      Copyright (C) 2006 CodeSourcery.
  19  *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
  20  *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
  21  *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
  22  *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
  23  *  based heavily on:
  24  *
  25  *  linux/fs/binfmt_aout.c:
  26  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
  27  *  linux/fs/binfmt_flat.c for 2.0 kernel
  28  *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
  29  *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
  30  */
  31
  32 /* ??? ZFLAT and shared library support is currently disabled.  */
  33
  34 /****************************************************************************/
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <errno.h>
  39 #include <sys/mman.h>
  40 #include <unistd.h>
  41
  42 #include "qemu.h"
  43 #include "flat.h"
  44 #define ntohl(x) be32_to_cpu(x)
  45 #include <target_flat.h>
  46
  47 //#define DEBUG
  48
  49 #ifdef DEBUG
  50 #define DBG_FLT(...)    printf(__VA_ARGS__)
  51 #else
  52 #define DBG_FLT(...)
  53 #endif
  54
  55 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  56 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  57
  58 struct lib_info {
  59     abi_ulong start_code;       /* Start of text segment */
  60     abi_ulong start_data;       /* Start of data segment */
  61     abi_ulong end_data;         /* Start of bss section */
  62     abi_ulong start_brk;        /* End of data segment */
  63     abi_ulong text_len;         /* Length of text segment */
  64     abi_ulong entry;            /* Start address for this module */
  65     abi_ulong build_date;       /* When this one was compiled */
  66     short loaded;               /* Has this library been loaded? */
  67 };
  68
  69 #ifdef CONFIG_BINFMT_SHARED_FLAT
  70 static int load_flat_shared_library(int id, struct lib_info *p);
  71 #endif
  72
  73 struct linux_binprm;
  74
  75 /****************************************************************************/
  76 /*
  77  * create_flat_tables() parses the env- and arg-strings in new user
  78  * memory and creates the pointer tables from them, and puts their
  79  * addresses on the "stack", returning the new stack pointer value.
  80  */
  81
  82 /* Push a block of strings onto the guest stack.  */
  83 static abi_ulong copy_strings(abi_ulong p, int n, char **s)
  84 {
  85     int len;
  86
  87     while (n-- > 0) {
  88         len = strlen(s[n]) + 1;
  89         p -= len;
  90         memcpy_to_target(p, s[n], len);
  91     }
  92
  93     return p;
  94 }
  95
  96 static int target_pread(int fd, abi_ulong ptr, abi_ulong len,
  97                         abi_ulong offset)
  98 {
  99     void *buf;
 100     int ret;
 101
 102     buf = lock_user(VERIFY_WRITE, ptr, len, 0);
 103     ret = pread(fd, buf, len, offset);
 104     unlock_user(buf, ptr, len);
 105     return ret;
 106 }
 107 /****************************************************************************/
 108
 109 #ifdef CONFIG_BINFMT_ZFLAT
 110
 111 #include <linux/zlib.h>
 112
 113 #define LBUFSIZE        4000
 114
 115 /* gzip flag byte */
 116 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 117 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 118 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 119 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 120 #define COMMENT      0x10 /* bit 4 set: file comment present */
 121 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 122 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 123
 124 static int decompress_exec(
 125         struct linux_binprm *bprm,
 126         unsigned long offset,
 127         char *dst,
 128         long len,
 129         int fd)
 130 {
 131         unsigned char *buf;
 132         z_stream strm;
 133         loff_t fpos;
 134         int ret, retval;
 135
 136         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 137
 138         memset(&strm, 0, sizeof(strm));
 139         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 140         if (strm.workspace == NULL) {
 141                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 142                 return -ENOMEM;
 143         }
 144         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 145         if (buf == NULL) {
 146                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 147                 retval = -ENOMEM;
 148                 goto out_free;
 149         }
 150
 151         /* Read in first chunk of data and parse gzip header. */
 152         fpos = offset;
 153         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 154
 155         strm.next_in = buf;
 156         strm.avail_in = ret;
 157         strm.total_in = 0;
 158
 159         retval = -ENOEXEC;
 160
 161         /* Check minimum size -- gzip header */
 162         if (ret < 10) {
 163                 DBG_FLT("binfmt_flat: file too small?\n");
 164                 goto out_free_buf;
 165         }
 166
 167         /* Check gzip magic number */
 168         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 169                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 170                 goto out_free_buf;
 171         }
 172
 173         /* Check gzip method */
 174         if (buf[2] != 8) {
 175                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 176                 goto out_free_buf;
 177         }
 178         /* Check gzip flags */
 179         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 180             (buf[3] & RESERVED)) {
 181                 DBG_FLT("binfmt_flat: unknown flags?\n");
 182                 goto out_free_buf;
 183         }
 184
 185         ret = 10;
 186         if (buf[3] & EXTRA_FIELD) {
 187                 ret += 2 + buf[10] + (buf[11] << 8);
 188                 if (unlikely(LBUFSIZE == ret)) {
 189                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 190                         goto out_free_buf;
 191                 }
 192         }
 193         if (buf[3] & ORIG_NAME) {
 194                 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
 195                         ;
 196                 if (unlikely(LBUFSIZE == ret)) {
 197                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 198                         goto out_free_buf;
 199                 }
 200         }
 201         if (buf[3] & COMMENT) {
 202                 for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
 203                         ;
 204                 if (unlikely(LBUFSIZE == ret)) {
 205                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 206                         goto out_free_buf;
 207                 }
 208         }
 209
 210         strm.next_in += ret;
 211         strm.avail_in -= ret;
 212
 213         strm.next_out = dst;
 214         strm.avail_out = len;
 215         strm.total_out = 0;
 216
 217         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 218                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 219                 goto out_free_buf;
 220         }
 221
 222         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 223                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 224                 if (ret <= 0)
 225                         break;
 226                 if (ret >= (unsigned long) -4096)
 227                         break;
 228                 len -= ret;
 229
 230                 strm.next_in = buf;
 231                 strm.avail_in = ret;
 232                 strm.total_in = 0;
 233         }
 234
 235         if (ret < 0) {
 236                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 237                         ret, strm.msg);
 238                 goto out_zlib;
 239         }
 240
 241         retval = 0;
 242 out_zlib:
 243         zlib_inflateEnd(&strm);
 244 out_free_buf:
 245         kfree(buf);
 246 out_free:
 247         kfree(strm.workspace);
 248 out:
 249         return retval;
 250 }
 251
 252 #endif /* CONFIG_BINFMT_ZFLAT */
 253
 254 /****************************************************************************/
 255
 256 static abi_ulong
 257 calc_reloc(abi_ulong r, struct lib_info *p, int curid, int internalp)
 258 {
 259     abi_ulong addr;
 260     int id;
 261     abi_ulong start_brk;
 262     abi_ulong start_data;
 263     abi_ulong text_len;
 264     abi_ulong start_code;
 265
 266 #ifdef CONFIG_BINFMT_SHARED_FLAT
 267 #error needs checking
 268     if (r == 0)
 269         id = curid;     /* Relocs of 0 are always self referring */
 270     else {
 271         id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 272         r &= 0x00ffffff;        /* Trim ID off here */
 273     }
 274     if (id >= MAX_SHARED_LIBS) {
 275         fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n",
 276                 (unsigned) r, id);
 277         goto failed;
 278     }
 279     if (curid != id) {
 280         if (internalp) {
 281             fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not "
 282                     "in same module (%d != %d)\n",
 283                     (unsigned) r, curid, id);
 284             goto failed;
 285         } else if ( ! p[id].loaded &&
 286                     load_flat_shared_library(id, p) > (unsigned long) -4096) {
 287             fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id);
 288             goto failed;
 289         }
 290         /* Check versioning information (i.e. time stamps) */
 291         if (p[id].build_date && p[curid].build_date
 292             && p[curid].build_date < p[id].build_date) {
 293             fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n",
 294                     id, curid);
 295             goto failed;
 296         }
 297     }
 298 #else
 299     id = 0;
 300 #endif
 301
 302     start_brk = p[id].start_brk;
 303     start_data = p[id].start_data;
 304     start_code = p[id].start_code;
 305     text_len = p[id].text_len;
 306
 307     if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 308         fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x "
 309                 "(0 - 0x%x/0x%x)\n",
 310                (int) r,(int)(start_brk-start_code),(int)text_len);
 311         goto failed;
 312     }
 313
 314     if (r < text_len)                   /* In text segment */
 315         addr = r + start_code;
 316     else                                        /* In data segment */
 317         addr = r - text_len + start_data;
 318
 319     /* Range checked already above so doing the range tests is redundant...*/
 320     return(addr);
 321
 322 failed:
 323     abort();
 324     return RELOC_FAILED;
 325 }
 326
 327 /****************************************************************************/
 328
 329 /* ??? This does not handle endianness correctly.  */
 330 static void old_reloc(struct lib_info *libinfo, uint32_t rl)
 331 {
 332 #ifdef DEBUG
 333         const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 334 #endif
 335         uint32_t *ptr;
 336         uint32_t offset;
 337         int reloc_type;
 338
 339         offset = rl & 0x3fffffff;
 340         reloc_type = rl >> 30;
 341         /* ??? How to handle this?  */
 342 #if defined(CONFIG_COLDFIRE)
 343         ptr = (uint32_t *) ((unsigned long) libinfo->start_code + offset);
 344 #else
 345         ptr = (uint32_t *) ((unsigned long) libinfo->start_data + offset);
 346 #endif
 347
 348 #ifdef DEBUG
 349         fprintf(stderr, "Relocation of variable at DATASEG+%x "
 350                 "(address %p, currently %x) into segment %s\n",
 351                 offset, ptr, (int)*ptr, segment[reloc_type]);
 352 #endif
 353
 354         switch (reloc_type) {
 355         case OLD_FLAT_RELOC_TYPE_TEXT:
 356                 *ptr += libinfo->start_code;
 357                 break;
 358         case OLD_FLAT_RELOC_TYPE_DATA:
 359                 *ptr += libinfo->start_data;
 360                 break;
 361         case OLD_FLAT_RELOC_TYPE_BSS:
 362                 *ptr += libinfo->end_data;
 363                 break;
 364         default:
 365                 fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n",
 366                         reloc_type);
 367                 break;
 368         }
 369         DBG_FLT("Relocation became %x\n", (int)*ptr);
 370 }
 371
 372 /****************************************************************************/
 373
 374 static int load_flat_file(struct linux_binprm * bprm,
 375                 struct lib_info *libinfo, int id, abi_ulong *extra_stack)
 376 {
 377     struct flat_hdr * hdr;
 378     abi_ulong textpos = 0, datapos = 0;
 379     abi_long result;
 380     abi_ulong realdatastart = 0;
 381     abi_ulong text_len, data_len, bss_len, stack_len, flags;
 382     abi_ulong extra;
 383     abi_ulong reloc = 0, rp;
 384     int i, rev, relocs = 0;
 385     abi_ulong fpos;
 386     abi_ulong start_code;
 387     abi_ulong indx_len;
 388
 389     hdr = ((struct flat_hdr *) bprm->buf);              /* exec-header */
 390
 391     text_len  = ntohl(hdr->data_start);
 392     data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 393     bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 394     stack_len = ntohl(hdr->stack_size);
 395     if (extra_stack) {
 396         stack_len += *extra_stack;
 397         *extra_stack = stack_len;
 398     }
 399     relocs    = ntohl(hdr->reloc_count);
 400     flags     = ntohl(hdr->flags);
 401     rev       = ntohl(hdr->rev);
 402
 403     DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 404
 405     if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 406         fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
 407                 rev, (int) FLAT_VERSION);
 408         return -ENOEXEC;
 409     }
 410
 411     /* Don't allow old format executables to use shared libraries */
 412     if (rev == OLD_FLAT_VERSION && id != 0) {
 413         fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n");
 414         return -ENOEXEC;
 415     }
 416
 417     /*
 418      * fix up the flags for the older format,  there were all kinds
 419      * of endian hacks,  this only works for the simple cases
 420      */
 421     if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 422         flags = FLAT_FLAG_RAM;
 423
 424 #ifndef CONFIG_BINFMT_ZFLAT
 425     if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 426         fprintf(stderr, "Support for ZFLAT executables is not enabled\n");
 427         return -ENOEXEC;
 428     }
 429 #endif
 430
 431     /*
 432      * calculate the extra space we need to map in
 433      */
 434     extra = relocs * sizeof(abi_ulong);
 435     if (extra < bss_len + stack_len)
 436         extra = bss_len + stack_len;
 437
 438     /* Add space for library base pointers.  Make sure this does not
 439        misalign the  doesn't misalign the data segment.  */
 440     indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong);
 441     indx_len = (indx_len + 15) & ~(abi_ulong)15;
 442
 443     /*
 444      * there are a couple of cases here,  the separate code/data
 445      * case,  and then the fully copied to RAM case which lumps
 446      * it all together.
 447      */
 448     if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 449         /*
 450          * this should give us a ROM ptr,  but if it doesn't we don't
 451          * really care
 452          */
 453         DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 454
 455         textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC,
 456                               MAP_PRIVATE, bprm->fd, 0);
 457         if (textpos == -1) {
 458             fprintf(stderr, "Unable to mmap process text\n");
 459             return -1;
 460         }
 461
 462         realdatastart = target_mmap(0, data_len + extra + indx_len,
 463                                     PROT_READ|PROT_WRITE|PROT_EXEC,
 464                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 465
 466         if (realdatastart == -1) {
 467             fprintf(stderr, "Unable to allocate RAM for process data\n");
 468             return realdatastart;
 469         }
 470         datapos = realdatastart + indx_len;
 471
 472         DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 473                         (int)(data_len + bss_len + stack_len), (int)datapos);
 474
 475         fpos = ntohl(hdr->data_start);
 476 #ifdef CONFIG_BINFMT_ZFLAT
 477         if (flags & FLAT_FLAG_GZDATA) {
 478             result = decompress_exec(bprm, fpos, (char *) datapos,
 479                                      data_len + (relocs * sizeof(abi_ulong)))
 480         } else
 481 #endif
 482         {
 483             result = target_pread(bprm->fd, datapos,
 484                                   data_len + (relocs * sizeof(abi_ulong)),
 485                                   fpos);
 486         }
 487         if (result < 0) {
 488             fprintf(stderr, "Unable to read data+bss\n");
 489             return result;
 490         }
 491
 492         reloc = datapos + (ntohl(hdr->reloc_start) - text_len);
 493
 494     } else {
 495
 496         textpos = target_mmap(0, text_len + data_len + extra + indx_len,
 497                               PROT_READ | PROT_EXEC | PROT_WRITE,
 498                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 499         if (textpos == -1 ) {
 500             fprintf(stderr, "Unable to allocate RAM for process text/data\n");
 501             return -1;
 502         }
 503
 504         realdatastart = textpos + ntohl(hdr->data_start);
 505         datapos = realdatastart + indx_len;
 506         reloc = (textpos + ntohl(hdr->reloc_start) + indx_len);
 507
 508 #ifdef CONFIG_BINFMT_ZFLAT
 509 #error code needs checking
 510         /*
 511          * load it all in and treat it like a RAM load from now on
 512          */
 513         if (flags & FLAT_FLAG_GZIP) {
 514                 result = decompress_exec(bprm, sizeof (struct flat_hdr),
 515                                  (((char *) textpos) + sizeof (struct flat_hdr)),
 516                                  (text_len + data_len + (relocs * sizeof(unsigned long))
 517                                           - sizeof (struct flat_hdr)),
 518                                  0);
 519                 memmove((void *) datapos, (void *) realdatastart,
 520                                 data_len + (relocs * sizeof(unsigned long)));
 521         } else if (flags & FLAT_FLAG_GZDATA) {
 522                 fpos = 0;
 523                 result = bprm->file->f_op->read(bprm->file,
 524                                 (char *) textpos, text_len, &fpos);
 525                 if (result < (unsigned long) -4096)
 526                         result = decompress_exec(bprm, text_len, (char *) datapos,
 527                                          data_len + (relocs * sizeof(unsigned long)), 0);
 528         }
 529         else
 530 #endif
 531         {
 532             result = target_pread(bprm->fd, textpos,
 533                                   text_len, 0);
 534             if (result >= 0) {
 535                 result = target_pread(bprm->fd, datapos,
 536                     data_len + (relocs * sizeof(abi_ulong)),
 537                     ntohl(hdr->data_start));
 538             }
 539         }
 540         if (result < 0) {
 541             fprintf(stderr, "Unable to read code+data+bss\n");
 542             return result;
 543         }
 544     }
 545
 546     DBG_FLT("Mapping is 0x%x, Entry point is 0x%x, data_start is 0x%x\n",
 547             (int)textpos, 0x00ffffff&ntohl(hdr->entry),
 548             ntohl(hdr->data_start));
 549
 550     /* The main program needs a little extra setup in the task structure */
 551     start_code = textpos + sizeof (struct flat_hdr);
 552
 553     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 554             id ? "Lib" : "Load", bprm->filename,
 555             (int) start_code, (int) (textpos + text_len),
 556             (int) datapos,
 557             (int) (datapos + data_len),
 558             (int) (datapos + data_len),
 559             (int) (((datapos + data_len + bss_len) + 3) & ~3));
 560
 561     text_len -= sizeof(struct flat_hdr); /* the real code len */
 562
 563     /* Store the current module values into the global library structure */
 564     libinfo[id].start_code = start_code;
 565     libinfo[id].start_data = datapos;
 566     libinfo[id].end_data = datapos + data_len;
 567     libinfo[id].start_brk = datapos + data_len + bss_len;
 568     libinfo[id].text_len = text_len;
 569     libinfo[id].loaded = 1;
 570     libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 571     libinfo[id].build_date = ntohl(hdr->build_date);
 572
 573     /*
 574      * We just load the allocations into some temporary memory to
 575      * help simplify all this mumbo jumbo
 576      *
 577      * We've got two different sections of relocation entries.
 578      * The first is the GOT which resides at the beginning of the data segment
 579      * and is terminated with a -1.  This one can be relocated in place.
 580      * The second is the extra relocation entries tacked after the image's
 581      * data segment. These require a little more processing as the entry is
 582      * really an offset into the image which contains an offset into the
 583      * image.
 584      */
 585     if (flags & FLAT_FLAG_GOTPIC) {
 586         rp = datapos;
 587         while (1) {
 588             abi_ulong addr;
 589             if (get_user_ual(addr, rp))
 590                 return -EFAULT;
 591             if (addr == -1)
 592                 break;
 593             if (addr) {
 594                 addr = calc_reloc(addr, libinfo, id, 0);
 595                 if (addr == RELOC_FAILED)
 596                     return -ENOEXEC;
 597                 if (put_user_ual(addr, rp))
 598                     return -EFAULT;
 599             }
 600             rp += sizeof(abi_ulong);
 601         }
 602     }
 603
 604     /*
 605      * Now run through the relocation entries.
 606      * We've got to be careful here as C++ produces relocatable zero
 607      * entries in the constructor and destructor tables which are then
 608      * tested for being not zero (which will always occur unless we're
 609      * based from address zero).  This causes an endless loop as __start
 610      * is at zero.  The solution used is to not relocate zero addresses.
 611      * This has the negative side effect of not allowing a global data
 612      * reference to be statically initialised to _stext (I've moved
 613      * __start to address 4 so that is okay).
 614      */
 615     if (rev > OLD_FLAT_VERSION) {
 616         abi_ulong persistent = 0;
 617         for (i = 0; i < relocs; i++) {
 618             abi_ulong addr, relval;
 619
 620             /* Get the address of the pointer to be
 621                relocated (of course, the address has to be
 622                relocated first).  */
 623             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 624                 return -EFAULT;
 625             relval = ntohl(relval);
 626             if (flat_set_persistent(relval, &persistent))
 627                 continue;
 628             addr = flat_get_relocate_addr(relval);
 629             rp = calc_reloc(addr, libinfo, id, 1);
 630             if (rp == RELOC_FAILED)
 631                 return -ENOEXEC;
 632
 633             /* Get the pointer's value.  */
 634             if (get_user_ual(addr, rp))
 635                 return -EFAULT;
 636             addr = flat_get_addr_from_rp(addr, relval, flags, &persistent);
 637             if (addr != 0) {
 638                 /*
 639                  * Do the relocation.  PIC relocs in the data section are
 640                  * already in target order
 641                  */
 642                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 643                     addr = ntohl(addr);
 644                 addr = calc_reloc(addr, libinfo, id, 0);
 645                 if (addr == RELOC_FAILED)
 646                     return -ENOEXEC;
 647
 648                 /* Write back the relocated pointer.  */
 649                 if (flat_put_addr_at_rp(rp, addr, relval))
 650                     return -EFAULT;
 651             }
 652         }
 653     } else {
 654         for (i = 0; i < relocs; i++) {
 655             abi_ulong relval;
 656             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 657                 return -EFAULT;
 658             old_reloc(&libinfo[0], relval);
 659         }
 660     }
 661
 662     /* zero the BSS.  */
 663     memset(g2h(datapos + data_len), 0, bss_len);
 664
 665     return 0;
 666 }
 667
 668
 669 /****************************************************************************/
 670 #ifdef CONFIG_BINFMT_SHARED_FLAT
 671
 672 /*
 673  * Load a shared library into memory.  The library gets its own data
 674  * segment (including bss) but not argv/argc/environ.
 675  */
 676
 677 static int load_flat_shared_library(int id, struct lib_info *libs)
 678 {
 679         struct linux_binprm bprm;
 680         int res;
 681         char buf[16];
 682
 683         /* Create the file name */
 684         sprintf(buf, "/lib/lib%d.so", id);
 685
 686         /* Open the file up */
 687         bprm.filename = buf;
 688         bprm.file = open_exec(bprm.filename);
 689         res = PTR_ERR(bprm.file);
 690         if (IS_ERR(bprm.file))
 691                 return res;
 692
 693         res = prepare_binprm(&bprm);
 694
 695         if (res <= (unsigned long)-4096)
 696                 res = load_flat_file(&bprm, libs, id, NULL);
 697         if (bprm.file) {
 698                 allow_write_access(bprm.file);
 699                 fput(bprm.file);
 700                 bprm.file = NULL;
 701         }
 702         return(res);
 703 }
 704
 705 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 706
 707 int load_flt_binary(struct linux_binprm *bprm, struct image_info *info)
 708 {
 709     struct lib_info libinfo[MAX_SHARED_LIBS];
 710     abi_ulong p = bprm->p;
 711     abi_ulong stack_len;
 712     abi_ulong start_addr;
 713     abi_ulong sp;
 714     int res;
 715     int i, j;
 716
 717     memset(libinfo, 0, sizeof(libinfo));
 718     /*
 719      * We have to add the size of our arguments to our stack size
 720      * otherwise it's too easy for users to create stack overflows
 721      * by passing in a huge argument list.  And yes,  we have to be
 722      * pedantic and include space for the argv/envp array as it may have
 723      * a lot of entries.
 724      */
 725     stack_len = 0;
 726     for (i = 0; i < bprm->argc; ++i) {
 727         /* the argv strings */
 728         stack_len += strlen(bprm->argv[i]);
 729     }
 730     for (i = 0; i < bprm->envc; ++i) {
 731         /* the envp strings */
 732         stack_len += strlen(bprm->envp[i]);
 733     }
 734     stack_len += (bprm->argc + 1) * 4; /* the argv array */
 735     stack_len += (bprm->envc + 1) * 4; /* the envp array */
 736
 737
 738     res = load_flat_file(bprm, libinfo, 0, &stack_len);
 739     if (res > (unsigned long)-4096)
 740             return res;
 741
 742     /* Update data segment pointers for all libraries */
 743     for (i=0; i<MAX_SHARED_LIBS; i++) {
 744         if (libinfo[i].loaded) {
 745             abi_ulong p;
 746             p = libinfo[i].start_data;
 747             for (j=0; j<MAX_SHARED_LIBS; j++) {
 748                 p -= 4;
 749                 /* FIXME - handle put_user() failures */
 750                 if (put_user_ual(libinfo[j].loaded
 751                                  ? libinfo[j].start_data
 752                                  : UNLOADED_LIB,
 753                                  p))
 754                     return -EFAULT;
 755             }
 756         }
 757     }
 758
 759     p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4;
 760     DBG_FLT("p=%x\n", (int)p);
 761
 762     /* Copy argv/envp.  */
 763     p = copy_strings(p, bprm->envc, bprm->envp);
 764     p = copy_strings(p, bprm->argc, bprm->argv);
 765     /* Align stack.  */
 766     sp = p & ~(abi_ulong)(sizeof(abi_ulong) - 1);
 767     /* Enforce final stack alignment of 16 bytes.  This is sufficient
 768        for all current targets, and excess alignment is harmless.  */
 769     stack_len = bprm->envc + bprm->argc + 2;
 770     stack_len += 3;     /* argc, arvg, argp */
 771     stack_len *= sizeof(abi_ulong);
 772     if ((sp + stack_len) & 15)
 773         sp -= 16 - ((sp + stack_len) & 15);
 774     sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p,
 775                              flat_argvp_envp_on_stack());
 776
 777     /* Fake some return addresses to ensure the call chain will
 778      * initialise library in order for us.  We are required to call
 779      * lib 1 first, then 2, ... and finally the main program (id 0).
 780      */
 781     start_addr = libinfo[0].entry;
 782
 783 #ifdef CONFIG_BINFMT_SHARED_FLAT
 784 #error here
 785     for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 786             if (libinfo[i].loaded) {
 787                     /* Push previos first to call address */
 788                     --sp;
 789                     if (put_user_ual(start_addr, sp))
 790                         return -EFAULT;
 791                     start_addr = libinfo[i].entry;
 792             }
 793     }
 794 #endif
 795
 796     /* Stash our initial stack pointer into the mm structure */
 797     info->start_code = libinfo[0].start_code;
 798     info->end_code = libinfo[0].start_code = libinfo[0].text_len;
 799     info->start_data = libinfo[0].start_data;
 800     info->end_data = libinfo[0].end_data;
 801     info->start_brk = libinfo[0].start_brk;
 802     info->start_stack = sp;
 803     info->stack_limit = libinfo[0].start_brk;
 804     info->entry = start_addr;
 805     info->code_offset = info->start_code;
 806     info->data_offset = info->start_data - libinfo[0].text_len;
 807
 808     DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n",
 809             (int)info->entry, (int)info->start_stack);
 810
 811     return 0;
 812 }