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, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  *      Copyright (C) 2006 CodeSourcery.
  20  *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
  21  *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
  22  *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
  23  *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
  24  *  based heavily on:
  25  *
  26  *  linux/fs/binfmt_aout.c:
  27  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
  28  *  linux/fs/binfmt_flat.c for 2.0 kernel
  29  *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
  30  *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
  31  */
  32
  33 /* ??? ZFLAT and shared library support is currently disabled.  */
  34
  35 /****************************************************************************/
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <errno.h>
  40 #include <sys/mman.h>
  41 #include <unistd.h>
  42
  43 #include "qemu.h"
  44 #include "flat.h"
  45
  46 //#define DEBUG
  47
  48 #ifdef DEBUG
  49 #define DBG_FLT(a...)   printf(a)
  50 #else
  51 #define DBG_FLT(a...)
  52 #endif
  53
  54 #define flat_reloc_valid(reloc, size)             ((reloc) <= (size))
  55 #define flat_old_ram_flag(flag)                   (flag)
  56 #ifdef TARGET_WORDS_BIGENDIAN
  57 #define flat_get_relocate_addr(relval)            (relval)
  58 #else
  59 #define flat_get_relocate_addr(relval)            bswap32(relval)
  60 #endif
  61
  62 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  63 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  64
  65 struct lib_info {
  66     target_ulong start_code;    /* Start of text segment */
  67     target_ulong start_data;    /* Start of data segment */
  68     target_ulong end_data;      /* Start of bss section */
  69     target_ulong start_brk;     /* End of data segment */
  70     target_ulong text_len;      /* Length of text segment */
  71     target_ulong entry;         /* Start address for this module */
  72     target_ulong build_date;    /* When this one was compiled */
  73     short loaded;               /* Has this library been loaded? */
  74 };
  75
  76 #ifdef CONFIG_BINFMT_SHARED_FLAT
  77 static int load_flat_shared_library(int id, struct lib_info *p);
  78 #endif
  79
  80 struct linux_binprm;
  81
  82 #define ntohl(x) be32_to_cpu(x)
  83
  84 /****************************************************************************/
  85 /*
  86  * create_flat_tables() parses the env- and arg-strings in new user
  87  * memory and creates the pointer tables from them, and puts their
  88  * addresses on the "stack", returning the new stack pointer value.
  89  */
  90
  91 /* Push a block of strings onto the guest stack.  */
  92 static target_ulong copy_strings(target_ulong p, int n, char **s)
  93 {
  94     int len;
  95
  96     while (n-- > 0) {
  97         len = strlen(s[n]) + 1;
  98         p -= len;
  99         memcpy_to_target(p, s[n], len);
 100     }
 101
 102     return p;
 103 }
 104
 105 int target_pread(int fd, target_ulong ptr, target_ulong len,
 106                  target_ulong offset)
 107 {
 108     void *buf;
 109     int ret;
 110
 111     buf = lock_user(ptr, len, 0);
 112     ret = pread(fd, buf, len, offset);
 113     unlock_user(buf, ptr, len);
 114     return ret;
 115 }
 116 /****************************************************************************/
 117
 118 #ifdef CONFIG_BINFMT_ZFLAT
 119
 120 #include <linux/zlib.h>
 121
 122 #define LBUFSIZE        4000
 123
 124 /* gzip flag byte */
 125 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 126 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 127 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 128 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 129 #define COMMENT      0x10 /* bit 4 set: file comment present */
 130 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 131 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 132
 133 static int decompress_exec(
 134         struct linux_binprm *bprm,
 135         unsigned long offset,
 136         char *dst,
 137         long len,
 138         int fd)
 139 {
 140         unsigned char *buf;
 141         z_stream strm;
 142         loff_t fpos;
 143         int ret, retval;
 144
 145         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 146
 147         memset(&strm, 0, sizeof(strm));
 148         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 149         if (strm.workspace == NULL) {
 150                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 151                 return -ENOMEM;
 152         }
 153         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 154         if (buf == NULL) {
 155                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 156                 retval = -ENOMEM;
 157                 goto out_free;
 158         }
 159
 160         /* Read in first chunk of data and parse gzip header. */
 161         fpos = offset;
 162         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 163
 164         strm.next_in = buf;
 165         strm.avail_in = ret;
 166         strm.total_in = 0;
 167
 168         retval = -ENOEXEC;
 169
 170         /* Check minimum size -- gzip header */
 171         if (ret < 10) {
 172                 DBG_FLT("binfmt_flat: file too small?\n");
 173                 goto out_free_buf;
 174         }
 175
 176         /* Check gzip magic number */
 177         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 178                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 179                 goto out_free_buf;
 180         }
 181
 182         /* Check gzip method */
 183         if (buf[2] != 8) {
 184                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 185                 goto out_free_buf;
 186         }
 187         /* Check gzip flags */
 188         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 189             (buf[3] & RESERVED)) {
 190                 DBG_FLT("binfmt_flat: unknown flags?\n");
 191                 goto out_free_buf;
 192         }
 193
 194         ret = 10;
 195         if (buf[3] & EXTRA_FIELD) {
 196                 ret += 2 + buf[10] + (buf[11] << 8);
 197                 if (unlikely(LBUFSIZE == ret)) {
 198                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 199                         goto out_free_buf;
 200                 }
 201         }
 202         if (buf[3] & ORIG_NAME) {
 203                 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
 204                         ;
 205                 if (unlikely(LBUFSIZE == ret)) {
 206                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 207                         goto out_free_buf;
 208                 }
 209         }
 210         if (buf[3] & COMMENT) {
 211                 for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
 212                         ;
 213                 if (unlikely(LBUFSIZE == ret)) {
 214                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 215                         goto out_free_buf;
 216                 }
 217         }
 218
 219         strm.next_in += ret;
 220         strm.avail_in -= ret;
 221
 222         strm.next_out = dst;
 223         strm.avail_out = len;
 224         strm.total_out = 0;
 225
 226         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 227                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 228                 goto out_free_buf;
 229         }
 230
 231         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 232                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 233                 if (ret <= 0)
 234                         break;
 235                 if (ret >= (unsigned long) -4096)
 236                         break;
 237                 len -= ret;
 238
 239                 strm.next_in = buf;
 240                 strm.avail_in = ret;
 241                 strm.total_in = 0;
 242         }
 243
 244         if (ret < 0) {
 245                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 246                         ret, strm.msg);
 247                 goto out_zlib;
 248         }
 249
 250         retval = 0;
 251 out_zlib:
 252         zlib_inflateEnd(&strm);
 253 out_free_buf:
 254         kfree(buf);
 255 out_free:
 256         kfree(strm.workspace);
 257 out:
 258         return retval;
 259 }
 260
 261 #endif /* CONFIG_BINFMT_ZFLAT */
 262
 263 /****************************************************************************/
 264
 265 static target_ulong
 266 calc_reloc(target_ulong r, struct lib_info *p, int curid, int internalp)
 267 {
 268     target_ulong addr;
 269     int id;
 270     target_ulong start_brk;
 271     target_ulong start_data;
 272     target_ulong text_len;
 273     target_ulong start_code;
 274
 275 #ifdef CONFIG_BINFMT_SHARED_FLAT
 276 #error needs checking
 277     if (r == 0)
 278         id = curid;     /* Relocs of 0 are always self referring */
 279     else {
 280         id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 281         r &= 0x00ffffff;        /* Trim ID off here */
 282     }
 283     if (id >= MAX_SHARED_LIBS) {
 284         fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n",
 285                 (unsigned) r, id);
 286         goto failed;
 287     }
 288     if (curid != id) {
 289         if (internalp) {
 290             fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not "
 291                     "in same module (%d != %d)\n",
 292                     (unsigned) r, curid, id);
 293             goto failed;
 294         } else if ( ! p[id].loaded &&
 295                     load_flat_shared_library(id, p) > (unsigned long) -4096) {
 296             fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id);
 297             goto failed;
 298         }
 299         /* Check versioning information (i.e. time stamps) */
 300         if (p[id].build_date && p[curid].build_date
 301             && p[curid].build_date < p[id].build_date) {
 302             fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n",
 303                     id, curid);
 304             goto failed;
 305         }
 306     }
 307 #else
 308     id = 0;
 309 #endif
 310
 311     start_brk = p[id].start_brk;
 312     start_data = p[id].start_data;
 313     start_code = p[id].start_code;
 314     text_len = p[id].text_len;
 315
 316     if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 317         fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x "
 318                 "(0 - 0x%x/0x%x)\n",
 319                (int) r,(int)(start_brk-start_code),(int)text_len);
 320         goto failed;
 321     }
 322
 323     if (r < text_len)                   /* In text segment */
 324         addr = r + start_code;
 325     else                                        /* In data segment */
 326         addr = r - text_len + start_data;
 327
 328     /* Range checked already above so doing the range tests is redundant...*/
 329     return(addr);
 330
 331 failed:
 332     abort();
 333     return RELOC_FAILED;
 334 }
 335
 336 /****************************************************************************/
 337
 338 /* ??? This does not handle endianness correctly.  */
 339 void old_reloc(struct lib_info *libinfo, uint32_t rl)
 340 {
 341 #ifdef DEBUG
 342         char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 343 #endif
 344         uint32_t *ptr;
 345         uint32_t offset;
 346         int reloc_type;
 347
 348         offset = rl & 0x3fffffff;
 349         reloc_type = rl >> 30;
 350         /* ??? How to handle this?  */
 351 #if defined(CONFIG_COLDFIRE)
 352         ptr = (uint32_t *) (libinfo->start_code + offset);
 353 #else
 354         ptr = (uint32_t *) (libinfo->start_data + offset);
 355 #endif
 356
 357 #ifdef DEBUG
 358         fprintf(stderr, "Relocation of variable at DATASEG+%x "
 359                 "(address %p, currently %x) into segment %s\n",
 360                 offset, ptr, (int)*ptr, segment[reloc_type]);
 361 #endif
 362
 363         switch (reloc_type) {
 364         case OLD_FLAT_RELOC_TYPE_TEXT:
 365                 *ptr += libinfo->start_code;
 366                 break;
 367         case OLD_FLAT_RELOC_TYPE_DATA:
 368                 *ptr += libinfo->start_data;
 369                 break;
 370         case OLD_FLAT_RELOC_TYPE_BSS:
 371                 *ptr += libinfo->end_data;
 372                 break;
 373         default:
 374                 fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n",
 375                         reloc_type);
 376                 break;
 377         }
 378         DBG_FLT("Relocation became %x\n", (int)*ptr);
 379 }
 380
 381 /****************************************************************************/
 382
 383 static int load_flat_file(struct linux_binprm * bprm,
 384                 struct lib_info *libinfo, int id, target_ulong *extra_stack)
 385 {
 386     struct flat_hdr * hdr;
 387     target_ulong textpos = 0, datapos = 0, result;
 388     target_ulong realdatastart = 0;
 389     target_ulong text_len, data_len, bss_len, stack_len, flags;
 390     target_ulong memp = 0; /* for finding the brk area */
 391     target_ulong extra;
 392     target_ulong reloc = 0, rp;
 393     int i, rev, relocs = 0;
 394     target_ulong fpos;
 395     target_ulong start_code, end_code;
 396     target_ulong indx_len;
 397
 398     hdr = ((struct flat_hdr *) bprm->buf);              /* exec-header */
 399
 400     text_len  = ntohl(hdr->data_start);
 401     data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 402     bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 403     stack_len = ntohl(hdr->stack_size);
 404     if (extra_stack) {
 405         stack_len += *extra_stack;
 406         *extra_stack = stack_len;
 407     }
 408     relocs    = ntohl(hdr->reloc_count);
 409     flags     = ntohl(hdr->flags);
 410     rev       = ntohl(hdr->rev);
 411
 412     DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 413
 414     if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 415         fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
 416                 rev, (int) FLAT_VERSION);
 417         return -ENOEXEC;
 418     }
 419
 420     /* Don't allow old format executables to use shared libraries */
 421     if (rev == OLD_FLAT_VERSION && id != 0) {
 422         fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n");
 423         return -ENOEXEC;
 424     }
 425
 426     /*
 427      * fix up the flags for the older format,  there were all kinds
 428      * of endian hacks,  this only works for the simple cases
 429      */
 430     if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 431         flags = FLAT_FLAG_RAM;
 432
 433 #ifndef CONFIG_BINFMT_ZFLAT
 434     if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 435         fprintf(stderr, "Support for ZFLAT executables is not enabled\n");
 436         return -ENOEXEC;
 437     }
 438 #endif
 439
 440     /*
 441      * calculate the extra space we need to map in
 442      */
 443     extra = relocs * sizeof(target_ulong);
 444     if (extra < bss_len + stack_len)
 445         extra = bss_len + stack_len;
 446
 447     /* Add space for library base pointers.  Make sure this does not
 448        misalign the  doesn't misalign the data segment.  */
 449     indx_len = MAX_SHARED_LIBS * sizeof(target_ulong);
 450     indx_len = (indx_len + 15) & ~(target_ulong)15;
 451
 452     /*
 453      * there are a couple of cases here,  the separate code/data
 454      * case,  and then the fully copied to RAM case which lumps
 455      * it all together.
 456      */
 457     if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 458         /*
 459          * this should give us a ROM ptr,  but if it doesn't we don't
 460          * really care
 461          */
 462         DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 463
 464         textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC,
 465                               MAP_PRIVATE, bprm->fd, 0);
 466         if (textpos == -1) {
 467             fprintf(stderr, "Unable to mmap process text\n");
 468             return -1;
 469         }
 470
 471         realdatastart = target_mmap(0, data_len + extra + indx_len,
 472                                     PROT_READ|PROT_WRITE|PROT_EXEC,
 473                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 474
 475         if (realdatastart == -1) {
 476             fprintf(stderr, "Unable to allocate RAM for process data\n");
 477             return realdatastart;
 478         }
 479         datapos = realdatastart + indx_len;
 480
 481         DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 482                         (int)(data_len + bss_len + stack_len), (int)datapos);
 483
 484         fpos = ntohl(hdr->data_start);
 485 #ifdef CONFIG_BINFMT_ZFLAT
 486         if (flags & FLAT_FLAG_GZDATA) {
 487             result = decompress_exec(bprm, fpos, (char *) datapos,
 488                                      data_len + (relocs * sizeof(target_ulong)))
 489         } else
 490 #endif
 491         {
 492             result = target_pread(bprm->fd, datapos,
 493                                   data_len + (relocs * sizeof(target_ulong)),
 494                                   fpos);
 495         }
 496         if (result < 0) {
 497             fprintf(stderr, "Unable to read data+bss\n");
 498             return result;
 499         }
 500
 501         reloc = datapos + (ntohl(hdr->reloc_start) - text_len);
 502         memp = realdatastart;
 503
 504     } else {
 505
 506         textpos = target_mmap(0, text_len + data_len + extra + indx_len,
 507                               PROT_READ | PROT_EXEC | PROT_WRITE,
 508                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 509         if (textpos == -1 ) {
 510             fprintf(stderr, "Unable to allocate RAM for process text/data\n");
 511             return -1;
 512         }
 513
 514         realdatastart = textpos + ntohl(hdr->data_start);
 515         datapos = realdatastart + indx_len;
 516         reloc = (textpos + ntohl(hdr->reloc_start) + indx_len);
 517         memp = textpos;
 518
 519 #ifdef CONFIG_BINFMT_ZFLAT
 520 #error code needs checking
 521         /*
 522          * load it all in and treat it like a RAM load from now on
 523          */
 524         if (flags & FLAT_FLAG_GZIP) {
 525                 result = decompress_exec(bprm, sizeof (struct flat_hdr),
 526                                  (((char *) textpos) + sizeof (struct flat_hdr)),
 527                                  (text_len + data_len + (relocs * sizeof(unsigned long))
 528                                           - sizeof (struct flat_hdr)),
 529                                  0);
 530                 memmove((void *) datapos, (void *) realdatastart,
 531                                 data_len + (relocs * sizeof(unsigned long)));
 532         } else if (flags & FLAT_FLAG_GZDATA) {
 533                 fpos = 0;
 534                 result = bprm->file->f_op->read(bprm->file,
 535                                 (char *) textpos, text_len, &fpos);
 536                 if (result < (unsigned long) -4096)
 537                         result = decompress_exec(bprm, text_len, (char *) datapos,
 538                                          data_len + (relocs * sizeof(unsigned long)), 0);
 539         }
 540         else
 541 #endif
 542         {
 543             result = target_pread(bprm->fd, textpos,
 544                                   text_len, 0);
 545             if (result >= 0) {
 546                 result = target_pread(bprm->fd, datapos,
 547                     data_len + (relocs * sizeof(target_ulong)),
 548                     ntohl(hdr->data_start));
 549             }
 550         }
 551         if (result < 0) {
 552             fprintf(stderr, "Unable to read code+data+bss\n");
 553             return result;
 554         }
 555     }
 556
 557     DBG_FLT("Mapping is 0x%x, Entry point is 0x%x, data_start is 0x%x\n",
 558             (int)textpos, 0x00ffffff&ntohl(hdr->entry),
 559             ntohl(hdr->data_start));
 560
 561     /* The main program needs a little extra setup in the task structure */
 562     start_code = textpos + sizeof (struct flat_hdr);
 563     end_code = textpos + text_len;
 564
 565     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 566             id ? "Lib" : "Load", bprm->filename,
 567             (int) start_code, (int) end_code,
 568             (int) datapos,
 569             (int) (datapos + data_len),
 570             (int) (datapos + data_len),
 571             (int) (((datapos + data_len + bss_len) + 3) & ~3));
 572
 573     text_len -= sizeof(struct flat_hdr); /* the real code len */
 574
 575     /* Store the current module values into the global library structure */
 576     libinfo[id].start_code = start_code;
 577     libinfo[id].start_data = datapos;
 578     libinfo[id].end_data = datapos + data_len;
 579     libinfo[id].start_brk = datapos + data_len + bss_len;
 580     libinfo[id].text_len = text_len;
 581     libinfo[id].loaded = 1;
 582     libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 583     libinfo[id].build_date = ntohl(hdr->build_date);
 584
 585     /*
 586      * We just load the allocations into some temporary memory to
 587      * help simplify all this mumbo jumbo
 588      *
 589      * We've got two different sections of relocation entries.
 590      * The first is the GOT which resides at the begining of the data segment
 591      * and is terminated with a -1.  This one can be relocated in place.
 592      * The second is the extra relocation entries tacked after the image's
 593      * data segment. These require a little more processing as the entry is
 594      * really an offset into the image which contains an offset into the
 595      * image.
 596      */
 597     if (flags & FLAT_FLAG_GOTPIC) {
 598         rp = datapos;
 599         while (1) {
 600             target_ulong addr;
 601             addr = tgetl(rp);
 602             if (addr == -1)
 603                 break;
 604             if (addr) {
 605                 addr = calc_reloc(addr, libinfo, id, 0);
 606                 if (addr == RELOC_FAILED)
 607                     return -ENOEXEC;
 608                 tputl(rp, addr);
 609             }
 610             rp += sizeof(target_ulong);
 611         }
 612     }
 613
 614     /*
 615      * Now run through the relocation entries.
 616      * We've got to be careful here as C++ produces relocatable zero
 617      * entries in the constructor and destructor tables which are then
 618      * tested for being not zero (which will always occur unless we're
 619      * based from address zero).  This causes an endless loop as __start
 620      * is at zero.  The solution used is to not relocate zero addresses.
 621      * This has the negative side effect of not allowing a global data
 622      * reference to be statically initialised to _stext (I've moved
 623      * __start to address 4 so that is okay).
 624      */
 625     if (rev > OLD_FLAT_VERSION) {
 626         for (i = 0; i < relocs; i++) {
 627             target_ulong addr, relval;
 628
 629             /* Get the address of the pointer to be
 630                relocated (of course, the address has to be
 631                relocated first).  */
 632             relval = tgetl(reloc + i * sizeof (target_ulong));
 633             addr = flat_get_relocate_addr(relval);
 634             rp = calc_reloc(addr, libinfo, id, 1);
 635             if (rp == RELOC_FAILED)
 636                 return -ENOEXEC;
 637
 638             /* Get the pointer's value.  */
 639             addr = tgetl(rp);
 640             if (addr != 0) {
 641                 /*
 642                  * Do the relocation.  PIC relocs in the data section are
 643                  * already in target order
 644                  */
 645
 646 #ifndef TARGET_WORDS_BIGENDIAN
 647                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 648                     addr = bswap32(addr);
 649 #endif
 650                 addr = calc_reloc(addr, libinfo, id, 0);
 651                 if (addr == RELOC_FAILED)
 652                     return -ENOEXEC;
 653
 654                 /* Write back the relocated pointer.  */
 655                 tputl(rp, addr);
 656             }
 657         }
 658     } else {
 659         for (i = 0; i < relocs; i++) {
 660             target_ulong relval;
 661             relval = tgetl(reloc + i * sizeof (target_ulong));
 662             old_reloc(&libinfo[0], relval);
 663         }
 664     }
 665
 666     /* zero the BSS.  */
 667     memset((void*)(datapos + data_len), 0, bss_len);
 668
 669     return 0;
 670 }
 671
 672
 673 /****************************************************************************/
 674 #ifdef CONFIG_BINFMT_SHARED_FLAT
 675
 676 /*
 677  * Load a shared library into memory.  The library gets its own data
 678  * segment (including bss) but not argv/argc/environ.
 679  */
 680
 681 static int load_flat_shared_library(int id, struct lib_info *libs)
 682 {
 683         struct linux_binprm bprm;
 684         int res;
 685         char buf[16];
 686
 687         /* Create the file name */
 688         sprintf(buf, "/lib/lib%d.so", id);
 689
 690         /* Open the file up */
 691         bprm.filename = buf;
 692         bprm.file = open_exec(bprm.filename);
 693         res = PTR_ERR(bprm.file);
 694         if (IS_ERR(bprm.file))
 695                 return res;
 696
 697         res = prepare_binprm(&bprm);
 698
 699         if (res <= (unsigned long)-4096)
 700                 res = load_flat_file(&bprm, libs, id, NULL);
 701         if (bprm.file) {
 702                 allow_write_access(bprm.file);
 703                 fput(bprm.file);
 704                 bprm.file = NULL;
 705         }
 706         return(res);
 707 }
 708
 709 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 710
 711 int load_flt_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
 712                     struct image_info * info)
 713 {
 714     struct lib_info libinfo[MAX_SHARED_LIBS];
 715     target_ulong p = bprm->p;
 716     target_ulong stack_len;
 717     target_ulong start_addr;
 718     target_ulong sp;
 719     int res;
 720     int i, j;
 721
 722     memset(libinfo, 0, sizeof(libinfo));
 723     /*
 724      * We have to add the size of our arguments to our stack size
 725      * otherwise it's too easy for users to create stack overflows
 726      * by passing in a huge argument list.  And yes,  we have to be
 727      * pedantic and include space for the argv/envp array as it may have
 728      * a lot of entries.
 729      */
 730 #define TOP_OF_ARGS (TARGET_PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
 731     stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
 732     stack_len += (bprm->argc + 1) * 4; /* the argv array */
 733     stack_len += (bprm->envc + 1) * 4; /* the envp array */
 734
 735
 736     res = load_flat_file(bprm, libinfo, 0, &stack_len);
 737     if (res > (unsigned long)-4096)
 738             return res;
 739
 740     /* Update data segment pointers for all libraries */
 741     for (i=0; i<MAX_SHARED_LIBS; i++) {
 742         if (libinfo[i].loaded) {
 743             target_ulong p;
 744             p = libinfo[i].start_data;
 745             for (j=0; j<MAX_SHARED_LIBS; j++) {
 746                 p -= 4;
 747                 tput32(p, libinfo[j].loaded
 748                           ? libinfo[j].start_data
 749                           : UNLOADED_LIB);
 750             }
 751         }
 752     }
 753
 754     p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4;
 755     DBG_FLT("p=%x\n", (int)p);
 756
 757     /* Copy argv/envp.  */
 758     p = copy_strings(p, bprm->envc, bprm->envp);
 759     p = copy_strings(p, bprm->argc, bprm->argv);
 760     /* Align stack.  */
 761     sp = p & ~(target_ulong)(sizeof(target_ulong) - 1);
 762     /* Enforce final stack alignment of 16 bytes.  This is sufficient
 763        for all current targets, and excess alignment is harmless.  */
 764     stack_len = bprm->envc + bprm->argc + 2;
 765     stack_len += 3;     /* argc, arvg, argp */
 766     stack_len *= sizeof(target_ulong);
 767     if ((sp + stack_len) & 15)
 768         sp -= 16 - ((sp + stack_len) & 15);
 769     sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p, 1);
 770
 771     /* Fake some return addresses to ensure the call chain will
 772      * initialise library in order for us.  We are required to call
 773      * lib 1 first, then 2, ... and finally the main program (id 0).
 774      */
 775     start_addr = libinfo[0].entry;
 776
 777 #ifdef CONFIG_BINFMT_SHARED_FLAT
 778 #error here
 779     for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 780             if (libinfo[i].loaded) {
 781                     /* Push previos first to call address */
 782                     --sp;       put_user(start_addr, sp);
 783                     start_addr = libinfo[i].entry;
 784             }
 785     }
 786 #endif
 787
 788     /* Stash our initial stack pointer into the mm structure */
 789     info->start_code = libinfo[0].start_code;
 790     info->end_code = libinfo[0].start_code = libinfo[0].text_len;
 791     info->start_data = libinfo[0].start_data;
 792     info->end_data = libinfo[0].end_data;
 793     info->start_brk = libinfo[0].start_brk;
 794     info->start_stack = sp;
 795     info->entry = start_addr;
 796     info->code_offset = info->start_code;
 797     info->data_offset = info->start_data - libinfo[0].text_len;
 798
 799     DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n",
 800             (int)info->entry, (int)info->start_stack);
 801
 802     return 0;
 803 }