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 "qemu/osdep.h"
  37
  38 #include "qemu.h"
  39 #include "flat.h"
  40 #include "target_flat.h"
  41
  42 //#define DEBUG
  43
  44 #ifdef DEBUG
  45 #define DBG_FLT(...)    printf(__VA_ARGS__)
  46 #else
  47 #define DBG_FLT(...)
  48 #endif
  49
  50 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  51 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  52
  53 struct lib_info {
  54     abi_ulong start_code;       /* Start of text segment */
  55     abi_ulong start_data;       /* Start of data segment */
  56     abi_ulong end_data;         /* Start of bss section */
  57     abi_ulong start_brk;        /* End of data segment */
  58     abi_ulong text_len;         /* Length of text segment */
  59     abi_ulong entry;            /* Start address for this module */
  60     abi_ulong build_date;       /* When this one was compiled */
  61     short loaded;               /* Has this library been loaded? */
  62 };
  63
  64 #ifdef CONFIG_BINFMT_SHARED_FLAT
  65 static int load_flat_shared_library(int id, struct lib_info *p);
  66 #endif
  67
  68 struct linux_binprm;
  69
  70 /****************************************************************************/
  71 /*
  72  * create_flat_tables() parses the env- and arg-strings in new user
  73  * memory and creates the pointer tables from them, and puts their
  74  * addresses on the "stack", returning the new stack pointer value.
  75  */
  76
  77 /* Push a block of strings onto the guest stack.  */
  78 static abi_ulong copy_strings(abi_ulong p, int n, char **s)
  79 {
  80     int len;
  81
  82     while (n-- > 0) {
  83         len = strlen(s[n]) + 1;
  84         p -= len;
  85         memcpy_to_target(p, s[n], len);
  86     }
  87
  88     return p;
  89 }
  90
  91 static int target_pread(int fd, abi_ulong ptr, abi_ulong len,
  92                         abi_ulong offset)
  93 {
  94     void *buf;
  95     int ret;
  96
  97     buf = lock_user(VERIFY_WRITE, ptr, len, 0);
  98     if (!buf) {
  99         return -EFAULT;
 100     }
 101     ret = pread(fd, buf, len, offset);
 102     if (ret < 0) {
 103         ret = -errno;
 104     }
 105     unlock_user(buf, ptr, len);
 106     return ret;
 107 }
 108 /****************************************************************************/
 109
 110 #ifdef CONFIG_BINFMT_ZFLAT
 111
 112 #include <linux/zlib.h>
 113
 114 #define LBUFSIZE        4000
 115
 116 /* gzip flag byte */
 117 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 118 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 119 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 120 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 121 #define COMMENT      0x10 /* bit 4 set: file comment present */
 122 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 123 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 124
 125 static int decompress_exec(
 126         struct linux_binprm *bprm,
 127         unsigned long offset,
 128         char *dst,
 129         long len,
 130         int fd)
 131 {
 132         unsigned char *buf;
 133         z_stream strm;
 134         loff_t fpos;
 135         int ret, retval;
 136
 137         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 138
 139         memset(&strm, 0, sizeof(strm));
 140         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 141         if (strm.workspace == NULL) {
 142                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 143                 return -ENOMEM;
 144         }
 145         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 146         if (buf == NULL) {
 147                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 148                 retval = -ENOMEM;
 149                 goto out_free;
 150         }
 151
 152         /* Read in first chunk of data and parse gzip header. */
 153         fpos = offset;
 154         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 155
 156         strm.next_in = buf;
 157         strm.avail_in = ret;
 158         strm.total_in = 0;
 159
 160         retval = -ENOEXEC;
 161
 162         /* Check minimum size -- gzip header */
 163         if (ret < 10) {
 164                 DBG_FLT("binfmt_flat: file too small?\n");
 165                 goto out_free_buf;
 166         }
 167
 168         /* Check gzip magic number */
 169         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 170                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 171                 goto out_free_buf;
 172         }
 173
 174         /* Check gzip method */
 175         if (buf[2] != 8) {
 176                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 177                 goto out_free_buf;
 178         }
 179         /* Check gzip flags */
 180         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 181             (buf[3] & RESERVED)) {
 182                 DBG_FLT("binfmt_flat: unknown flags?\n");
 183                 goto out_free_buf;
 184         }
 185
 186         ret = 10;
 187         if (buf[3] & EXTRA_FIELD) {
 188                 ret += 2 + buf[10] + (buf[11] << 8);
 189                 if (unlikely(LBUFSIZE == ret)) {
 190                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 191                         goto out_free_buf;
 192                 }
 193         }
 194         if (buf[3] & ORIG_NAME) {
 195                 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
 196                         ;
 197                 if (unlikely(LBUFSIZE == ret)) {
 198                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 199                         goto out_free_buf;
 200                 }
 201         }
 202         if (buf[3] & COMMENT) {
 203                 for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
 204                         ;
 205                 if (unlikely(LBUFSIZE == ret)) {
 206                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 207                         goto out_free_buf;
 208                 }
 209         }
 210
 211         strm.next_in += ret;
 212         strm.avail_in -= ret;
 213
 214         strm.next_out = dst;
 215         strm.avail_out = len;
 216         strm.total_out = 0;
 217
 218         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 219                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 220                 goto out_free_buf;
 221         }
 222
 223         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 224                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 225                 if (ret <= 0)
 226                         break;
 227                 if (ret >= (unsigned long) -4096)
 228                         break;
 229                 len -= ret;
 230
 231                 strm.next_in = buf;
 232                 strm.avail_in = ret;
 233                 strm.total_in = 0;
 234         }
 235
 236         if (ret < 0) {
 237                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 238                         ret, strm.msg);
 239                 goto out_zlib;
 240         }
 241
 242         retval = 0;
 243 out_zlib:
 244         zlib_inflateEnd(&strm);
 245 out_free_buf:
 246         kfree(buf);
 247 out_free:
 248         kfree(strm.workspace);
 249 out:
 250         return retval;
 251 }
 252
 253 #endif /* CONFIG_BINFMT_ZFLAT */
 254
 255 /****************************************************************************/
 256
 257 static abi_ulong
 258 calc_reloc(abi_ulong r, struct lib_info *p, int curid, int internalp)
 259 {
 260     abi_ulong addr;
 261     int id;
 262     abi_ulong start_brk;
 263     abi_ulong start_data;
 264     abi_ulong text_len;
 265     abi_ulong start_code;
 266
 267 #ifdef CONFIG_BINFMT_SHARED_FLAT
 268 #error needs checking
 269     if (r == 0)
 270         id = curid;     /* Relocs of 0 are always self referring */
 271     else {
 272         id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 273         r &= 0x00ffffff;        /* Trim ID off here */
 274     }
 275     if (id >= MAX_SHARED_LIBS) {
 276         fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n",
 277                 (unsigned) r, id);
 278         goto failed;
 279     }
 280     if (curid != id) {
 281         if (internalp) {
 282             fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not "
 283                     "in same module (%d != %d)\n",
 284                     (unsigned) r, curid, id);
 285             goto failed;
 286         } else if ( ! p[id].loaded &&
 287                     load_flat_shared_library(id, p) > (unsigned long) -4096) {
 288             fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id);
 289             goto failed;
 290         }
 291         /* Check versioning information (i.e. time stamps) */
 292         if (p[id].build_date && p[curid].build_date
 293             && p[curid].build_date < p[id].build_date) {
 294             fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n",
 295                     id, curid);
 296             goto failed;
 297         }
 298     }
 299 #else
 300     id = 0;
 301 #endif
 302
 303     start_brk = p[id].start_brk;
 304     start_data = p[id].start_data;
 305     start_code = p[id].start_code;
 306     text_len = p[id].text_len;
 307
 308     if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 309         fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x "
 310                 "(0 - 0x%x/0x%x)\n",
 311                (int) r,(int)(start_brk-start_code),(int)text_len);
 312         goto failed;
 313     }
 314
 315     if (r < text_len)                   /* In text segment */
 316         addr = r + start_code;
 317     else                                        /* In data segment */
 318         addr = r - text_len + start_data;
 319
 320     /* Range checked already above so doing the range tests is redundant...*/
 321     return(addr);
 322
 323 failed:
 324     abort();
 325     return RELOC_FAILED;
 326 }
 327
 328 /****************************************************************************/
 329
 330 /* ??? This does not handle endianness correctly.  */
 331 static void old_reloc(struct lib_info *libinfo, uint32_t rl)
 332 {
 333 #ifdef DEBUG
 334         const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 335 #endif
 336         uint32_t *ptr;
 337         uint32_t offset;
 338         int reloc_type;
 339
 340         offset = rl & 0x3fffffff;
 341         reloc_type = rl >> 30;
 342         /* ??? How to handle this?  */
 343 #if defined(CONFIG_COLDFIRE)
 344         ptr = (uint32_t *) ((unsigned long) libinfo->start_code + offset);
 345 #else
 346         ptr = (uint32_t *) ((unsigned long) libinfo->start_data + offset);
 347 #endif
 348
 349 #ifdef DEBUG
 350         fprintf(stderr, "Relocation of variable at DATASEG+%x "
 351                 "(address %p, currently %x) into segment %s\n",
 352                 offset, ptr, (int)*ptr, segment[reloc_type]);
 353 #endif
 354
 355         switch (reloc_type) {
 356         case OLD_FLAT_RELOC_TYPE_TEXT:
 357                 *ptr += libinfo->start_code;
 358                 break;
 359         case OLD_FLAT_RELOC_TYPE_DATA:
 360                 *ptr += libinfo->start_data;
 361                 break;
 362         case OLD_FLAT_RELOC_TYPE_BSS:
 363                 *ptr += libinfo->end_data;
 364                 break;
 365         default:
 366                 fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n",
 367                         reloc_type);
 368                 break;
 369         }
 370         DBG_FLT("Relocation became %x\n", (int)*ptr);
 371 }
 372
 373 /****************************************************************************/
 374
 375 static int load_flat_file(struct linux_binprm * bprm,
 376                 struct lib_info *libinfo, int id, abi_ulong *extra_stack)
 377 {
 378     struct flat_hdr * hdr;
 379     abi_ulong textpos = 0, datapos = 0;
 380     abi_long result;
 381     abi_ulong realdatastart = 0;
 382     abi_ulong text_len, data_len, bss_len, stack_len, flags;
 383     abi_ulong extra;
 384     abi_ulong reloc = 0, rp;
 385     int i, rev, relocs = 0;
 386     abi_ulong fpos;
 387     abi_ulong start_code;
 388     abi_ulong indx_len;
 389
 390     hdr = ((struct flat_hdr *) bprm->buf);              /* exec-header */
 391
 392     text_len  = ntohl(hdr->data_start);
 393     data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 394     bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 395     stack_len = ntohl(hdr->stack_size);
 396     if (extra_stack) {
 397         stack_len += *extra_stack;
 398         *extra_stack = stack_len;
 399     }
 400     relocs    = ntohl(hdr->reloc_count);
 401     flags     = ntohl(hdr->flags);
 402     rev       = ntohl(hdr->rev);
 403
 404     DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 405
 406     if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 407         fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
 408                 rev, (int) FLAT_VERSION);
 409         return -ENOEXEC;
 410     }
 411
 412     /* Don't allow old format executables to use shared libraries */
 413     if (rev == OLD_FLAT_VERSION && id != 0) {
 414         fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n");
 415         return -ENOEXEC;
 416     }
 417
 418     /*
 419      * fix up the flags for the older format,  there were all kinds
 420      * of endian hacks,  this only works for the simple cases
 421      */
 422     if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 423         flags = FLAT_FLAG_RAM;
 424
 425 #ifndef CONFIG_BINFMT_ZFLAT
 426     if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 427         fprintf(stderr, "Support for ZFLAT executables is not enabled\n");
 428         return -ENOEXEC;
 429     }
 430 #endif
 431
 432     /*
 433      * calculate the extra space we need to map in
 434      */
 435     extra = relocs * sizeof(abi_ulong);
 436     if (extra < bss_len + stack_len)
 437         extra = bss_len + stack_len;
 438
 439     /* Add space for library base pointers.  Make sure this does not
 440        misalign the  doesn't misalign the data segment.  */
 441     indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong);
 442     indx_len = (indx_len + 15) & ~(abi_ulong)15;
 443
 444     /*
 445      * there are a couple of cases here,  the separate code/data
 446      * case,  and then the fully copied to RAM case which lumps
 447      * it all together.
 448      */
 449     if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 450         /*
 451          * this should give us a ROM ptr,  but if it doesn't we don't
 452          * really care
 453          */
 454         DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 455
 456         textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC,
 457                               MAP_PRIVATE, bprm->fd, 0);
 458         if (textpos == -1) {
 459             fprintf(stderr, "Unable to mmap process text\n");
 460             return -1;
 461         }
 462
 463         realdatastart = target_mmap(0, data_len + extra + indx_len,
 464                                     PROT_READ|PROT_WRITE|PROT_EXEC,
 465                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 466
 467         if (realdatastart == -1) {
 468             fprintf(stderr, "Unable to allocate RAM for process data\n");
 469             return realdatastart;
 470         }
 471         datapos = realdatastart + indx_len;
 472
 473         DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 474                         (int)(data_len + bss_len + stack_len), (int)datapos);
 475
 476         fpos = ntohl(hdr->data_start);
 477 #ifdef CONFIG_BINFMT_ZFLAT
 478         if (flags & FLAT_FLAG_GZDATA) {
 479             result = decompress_exec(bprm, fpos, (char *) datapos,
 480                                      data_len + (relocs * sizeof(abi_ulong)))
 481         } else
 482 #endif
 483         {
 484             result = target_pread(bprm->fd, datapos,
 485                                   data_len + (relocs * sizeof(abi_ulong)),
 486                                   fpos);
 487         }
 488         if (result < 0) {
 489             fprintf(stderr, "Unable to read data+bss\n");
 490             return result;
 491         }
 492
 493         reloc = datapos + (ntohl(hdr->reloc_start) - text_len);
 494
 495     } else {
 496
 497         textpos = target_mmap(0, text_len + data_len + extra + indx_len,
 498                               PROT_READ | PROT_EXEC | PROT_WRITE,
 499                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 500         if (textpos == -1 ) {
 501             fprintf(stderr, "Unable to allocate RAM for process text/data\n");
 502             return -1;
 503         }
 504
 505         realdatastart = textpos + ntohl(hdr->data_start);
 506         datapos = realdatastart + indx_len;
 507         reloc = (textpos + ntohl(hdr->reloc_start) + indx_len);
 508
 509 #ifdef CONFIG_BINFMT_ZFLAT
 510 #error code needs checking
 511         /*
 512          * load it all in and treat it like a RAM load from now on
 513          */
 514         if (flags & FLAT_FLAG_GZIP) {
 515                 result = decompress_exec(bprm, sizeof (struct flat_hdr),
 516                                  (((char *) textpos) + sizeof (struct flat_hdr)),
 517                                  (text_len + data_len + (relocs * sizeof(unsigned long))
 518                                           - sizeof (struct flat_hdr)),
 519                                  0);
 520                 memmove((void *) datapos, (void *) realdatastart,
 521                                 data_len + (relocs * sizeof(unsigned long)));
 522         } else if (flags & FLAT_FLAG_GZDATA) {
 523                 fpos = 0;
 524                 result = bprm->file->f_op->read(bprm->file,
 525                                 (char *) textpos, text_len, &fpos);
 526                 if (result < (unsigned long) -4096)
 527                         result = decompress_exec(bprm, text_len, (char *) datapos,
 528                                          data_len + (relocs * sizeof(unsigned long)), 0);
 529         }
 530         else
 531 #endif
 532         {
 533             result = target_pread(bprm->fd, textpos,
 534                                   text_len, 0);
 535             if (result >= 0) {
 536                 result = target_pread(bprm->fd, datapos,
 537                     data_len + (relocs * sizeof(abi_ulong)),
 538                     ntohl(hdr->data_start));
 539             }
 540         }
 541         if (result < 0) {
 542             fprintf(stderr, "Unable to read code+data+bss\n");
 543             return result;
 544         }
 545     }
 546
 547     DBG_FLT("Mapping is 0x%x, Entry point is 0x%x, data_start is 0x%x\n",
 548             (int)textpos, 0x00ffffff&ntohl(hdr->entry),
 549             ntohl(hdr->data_start));
 550
 551     /* The main program needs a little extra setup in the task structure */
 552     start_code = textpos + sizeof (struct flat_hdr);
 553
 554     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 555             id ? "Lib" : "Load", bprm->filename,
 556             (int) start_code, (int) (textpos + text_len),
 557             (int) datapos,
 558             (int) (datapos + data_len),
 559             (int) (datapos + data_len),
 560             (int) (((datapos + data_len + bss_len) + 3) & ~3));
 561
 562     text_len -= sizeof(struct flat_hdr); /* the real code len */
 563
 564     /* Store the current module values into the global library structure */
 565     libinfo[id].start_code = start_code;
 566     libinfo[id].start_data = datapos;
 567     libinfo[id].end_data = datapos + data_len;
 568     libinfo[id].start_brk = datapos + data_len + bss_len;
 569     libinfo[id].text_len = text_len;
 570     libinfo[id].loaded = 1;
 571     libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 572     libinfo[id].build_date = ntohl(hdr->build_date);
 573
 574     /*
 575      * We just load the allocations into some temporary memory to
 576      * help simplify all this mumbo jumbo
 577      *
 578      * We've got two different sections of relocation entries.
 579      * The first is the GOT which resides at the beginning of the data segment
 580      * and is terminated with a -1.  This one can be relocated in place.
 581      * The second is the extra relocation entries tacked after the image's
 582      * data segment. These require a little more processing as the entry is
 583      * really an offset into the image which contains an offset into the
 584      * image.
 585      */
 586     if (flags & FLAT_FLAG_GOTPIC) {
 587         rp = datapos;
 588         while (1) {
 589             abi_ulong addr;
 590             if (get_user_ual(addr, rp))
 591                 return -EFAULT;
 592             if (addr == -1)
 593                 break;
 594             if (addr) {
 595                 addr = calc_reloc(addr, libinfo, id, 0);
 596                 if (addr == RELOC_FAILED)
 597                     return -ENOEXEC;
 598                 if (put_user_ual(addr, rp))
 599                     return -EFAULT;
 600             }
 601             rp += sizeof(abi_ulong);
 602         }
 603     }
 604
 605     /*
 606      * Now run through the relocation entries.
 607      * We've got to be careful here as C++ produces relocatable zero
 608      * entries in the constructor and destructor tables which are then
 609      * tested for being not zero (which will always occur unless we're
 610      * based from address zero).  This causes an endless loop as __start
 611      * is at zero.  The solution used is to not relocate zero addresses.
 612      * This has the negative side effect of not allowing a global data
 613      * reference to be statically initialised to _stext (I've moved
 614      * __start to address 4 so that is okay).
 615      */
 616     if (rev > OLD_FLAT_VERSION) {
 617         abi_ulong persistent = 0;
 618         for (i = 0; i < relocs; i++) {
 619             abi_ulong addr, relval;
 620
 621             /* Get the address of the pointer to be
 622                relocated (of course, the address has to be
 623                relocated first).  */
 624             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 625                 return -EFAULT;
 626             relval = ntohl(relval);
 627             if (flat_set_persistent(relval, &persistent))
 628                 continue;
 629             addr = flat_get_relocate_addr(relval);
 630             rp = calc_reloc(addr, libinfo, id, 1);
 631             if (rp == RELOC_FAILED)
 632                 return -ENOEXEC;
 633
 634             /* Get the pointer's value.  */
 635             if (get_user_ual(addr, rp))
 636                 return -EFAULT;
 637             addr = flat_get_addr_from_rp(addr, relval, flags, &persistent);
 638             if (addr != 0) {
 639                 /*
 640                  * Do the relocation.  PIC relocs in the data section are
 641                  * already in target order
 642                  */
 643                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 644                     addr = ntohl(addr);
 645                 addr = calc_reloc(addr, libinfo, id, 0);
 646                 if (addr == RELOC_FAILED)
 647                     return -ENOEXEC;
 648
 649                 /* Write back the relocated pointer.  */
 650                 if (flat_put_addr_at_rp(rp, addr, relval))
 651                     return -EFAULT;
 652             }
 653         }
 654     } else {
 655         for (i = 0; i < relocs; i++) {
 656             abi_ulong relval;
 657             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 658                 return -EFAULT;
 659             old_reloc(&libinfo[0], relval);
 660         }
 661     }
 662
 663     /* zero the BSS.  */
 664     memset(g2h(datapos + data_len), 0, bss_len);
 665
 666     return 0;
 667 }
 668
 669
 670 /****************************************************************************/
 671 #ifdef CONFIG_BINFMT_SHARED_FLAT
 672
 673 /*
 674  * Load a shared library into memory.  The library gets its own data
 675  * segment (including bss) but not argv/argc/environ.
 676  */
 677
 678 static int load_flat_shared_library(int id, struct lib_info *libs)
 679 {
 680         struct linux_binprm bprm;
 681         int res;
 682         char buf[16];
 683
 684         /* Create the file name */
 685         sprintf(buf, "/lib/lib%d.so", id);
 686
 687         /* Open the file up */
 688         bprm.filename = buf;
 689         bprm.file = open_exec(bprm.filename);
 690         res = PTR_ERR(bprm.file);
 691         if (IS_ERR(bprm.file))
 692                 return res;
 693
 694         res = prepare_binprm(&bprm);
 695
 696         if (res <= (unsigned long)-4096)
 697                 res = load_flat_file(&bprm, libs, id, NULL);
 698         if (bprm.file) {
 699                 allow_write_access(bprm.file);
 700                 fput(bprm.file);
 701                 bprm.file = NULL;
 702         }
 703         return(res);
 704 }
 705
 706 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 707
 708 int load_flt_binary(struct linux_binprm *bprm, struct image_info *info)
 709 {
 710     struct lib_info libinfo[MAX_SHARED_LIBS];
 711     abi_ulong p;
 712     abi_ulong stack_len;
 713     abi_ulong start_addr;
 714     abi_ulong sp;
 715     int res;
 716     int i, j;
 717
 718     memset(libinfo, 0, sizeof(libinfo));
 719     /*
 720      * We have to add the size of our arguments to our stack size
 721      * otherwise it's too easy for users to create stack overflows
 722      * by passing in a huge argument list.  And yes,  we have to be
 723      * pedantic and include space for the argv/envp array as it may have
 724      * a lot of entries.
 725      */
 726     stack_len = 0;
 727     for (i = 0; i < bprm->argc; ++i) {
 728         /* the argv strings */
 729         stack_len += strlen(bprm->argv[i]);
 730     }
 731     for (i = 0; i < bprm->envc; ++i) {
 732         /* the envp strings */
 733         stack_len += strlen(bprm->envp[i]);
 734     }
 735     stack_len += (bprm->argc + 1) * 4; /* the argv array */
 736     stack_len += (bprm->envc + 1) * 4; /* the envp array */
 737
 738
 739     res = load_flat_file(bprm, libinfo, 0, &stack_len);
 740     if (res > (unsigned long)-4096)
 741             return res;
 742
 743     /* Update data segment pointers for all libraries */
 744     for (i=0; i<MAX_SHARED_LIBS; i++) {
 745         if (libinfo[i].loaded) {
 746             abi_ulong p;
 747             p = libinfo[i].start_data;
 748             for (j=0; j<MAX_SHARED_LIBS; j++) {
 749                 p -= 4;
 750                 /* FIXME - handle put_user() failures */
 751                 if (put_user_ual(libinfo[j].loaded
 752                                  ? libinfo[j].start_data
 753                                  : UNLOADED_LIB,
 754                                  p))
 755                     return -EFAULT;
 756             }
 757         }
 758     }
 759
 760     p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4;
 761     DBG_FLT("p=%x\n", (int)p);
 762
 763     /* Copy argv/envp.  */
 764     p = copy_strings(p, bprm->envc, bprm->envp);
 765     p = copy_strings(p, bprm->argc, bprm->argv);
 766     /* Align stack.  */
 767     sp = p & ~(abi_ulong)(sizeof(abi_ulong) - 1);
 768     /* Enforce final stack alignment of 16 bytes.  This is sufficient
 769        for all current targets, and excess alignment is harmless.  */
 770     stack_len = bprm->envc + bprm->argc + 2;
 771     stack_len += 3;     /* argc, arvg, argp */
 772     stack_len *= sizeof(abi_ulong);
 773     if ((sp + stack_len) & 15)
 774         sp -= 16 - ((sp + stack_len) & 15);
 775     sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p,
 776                              flat_argvp_envp_on_stack());
 777
 778     /* Fake some return addresses to ensure the call chain will
 779      * initialise library in order for us.  We are required to call
 780      * lib 1 first, then 2, ... and finally the main program (id 0).
 781      */
 782     start_addr = libinfo[0].entry;
 783
 784 #ifdef CONFIG_BINFMT_SHARED_FLAT
 785 #error here
 786     for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 787             if (libinfo[i].loaded) {
 788                     /* Push previos first to call address */
 789                     --sp;
 790                     if (put_user_ual(start_addr, sp))
 791                         return -EFAULT;
 792                     start_addr = libinfo[i].entry;
 793             }
 794     }
 795 #endif
 796
 797     /* Stash our initial stack pointer into the mm structure */
 798     info->start_code = libinfo[0].start_code;
 799     info->end_code = libinfo[0].start_code = libinfo[0].text_len;
 800     info->start_data = libinfo[0].start_data;
 801     info->end_data = libinfo[0].end_data;
 802     info->start_brk = libinfo[0].start_brk;
 803     info->start_stack = sp;
 804     info->stack_limit = libinfo[0].start_brk;
 805     info->entry = start_addr;
 806     info->code_offset = info->start_code;
 807     info->data_offset = info->start_data - libinfo[0].text_len;
 808
 809     DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n",
 810             (int)info->entry, (int)info->start_stack);
 811
 812     return 0;
 813 }