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 "user-internals.h"
  40 #include "loader.h"
  41 #include "user-mmap.h"
  42 #include "flat.h"
  43 #include "target_flat.h"
  44
  45 //#define DEBUG
  46
  47 #ifdef DEBUG
  48 #define DBG_FLT(...)    printf(__VA_ARGS__)
  49 #else
  50 #define DBG_FLT(...)
  51 #endif
  52
  53 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  54 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  55
  56 struct lib_info {
  57     abi_ulong start_code;       /* Start of text segment */
  58     abi_ulong start_data;       /* Start of data segment */
  59     abi_ulong end_data;         /* Start of bss section */
  60     abi_ulong start_brk;        /* End of data segment */
  61     abi_ulong text_len;         /* Length of text segment */
  62     abi_ulong entry;            /* Start address for this module */
  63     abi_ulong build_date;       /* When this one was compiled */
  64     short loaded;               /* Has this library been loaded? */
  65 };
  66
  67 #ifdef CONFIG_BINFMT_SHARED_FLAT
  68 static int load_flat_shared_library(int id, struct lib_info *p);
  69 #endif
  70
  71 struct linux_binprm;
  72
  73 /****************************************************************************/
  74 /*
  75  * create_flat_tables() parses the env- and arg-strings in new user
  76  * memory and creates the pointer tables from them, and puts their
  77  * addresses on the "stack", returning the new stack pointer value.
  78  */
  79
  80 /* Push a block of strings onto the guest stack.  */
  81 static abi_ulong copy_strings(abi_ulong p, int n, char **s)
  82 {
  83     int len;
  84
  85     while (n-- > 0) {
  86         len = strlen(s[n]) + 1;
  87         p -= len;
  88         memcpy_to_target(p, s[n], len);
  89     }
  90
  91     return p;
  92 }
  93
  94 static int target_pread(int fd, abi_ulong ptr, abi_ulong len,
  95                         abi_ulong offset)
  96 {
  97     void *buf;
  98     int ret;
  99
 100     buf = lock_user(VERIFY_WRITE, ptr, len, 0);
 101     if (!buf) {
 102         return -EFAULT;
 103     }
 104     ret = pread(fd, buf, len, offset);
 105     if (ret < 0) {
 106         ret = -errno;
 107     }
 108     unlock_user(buf, ptr, len);
 109     return ret;
 110 }
 111 /****************************************************************************/
 112
 113 #ifdef CONFIG_BINFMT_ZFLAT
 114
 115 #include <linux/zlib.h>
 116
 117 #define LBUFSIZE        4000
 118
 119 /* gzip flag byte */
 120 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 121 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 122 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 123 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 124 #define COMMENT      0x10 /* bit 4 set: file comment present */
 125 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 126 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 127
 128 static int decompress_exec(
 129         struct linux_binprm *bprm,
 130         unsigned long offset,
 131         char *dst,
 132         long len,
 133         int fd)
 134 {
 135         unsigned char *buf;
 136         z_stream strm;
 137         loff_t fpos;
 138         int ret, retval;
 139
 140         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 141
 142         memset(&strm, 0, sizeof(strm));
 143         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 144         if (strm.workspace == NULL) {
 145                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 146                 return -ENOMEM;
 147         }
 148         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 149         if (buf == NULL) {
 150                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 151                 retval = -ENOMEM;
 152                 goto out_free;
 153         }
 154
 155         /* Read in first chunk of data and parse gzip header. */
 156         fpos = offset;
 157         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 158
 159         strm.next_in = buf;
 160         strm.avail_in = ret;
 161         strm.total_in = 0;
 162
 163         retval = -ENOEXEC;
 164
 165         /* Check minimum size -- gzip header */
 166         if (ret < 10) {
 167                 DBG_FLT("binfmt_flat: file too small?\n");
 168                 goto out_free_buf;
 169         }
 170
 171         /* Check gzip magic number */
 172         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 173                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 174                 goto out_free_buf;
 175         }
 176
 177         /* Check gzip method */
 178         if (buf[2] != 8) {
 179                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 180                 goto out_free_buf;
 181         }
 182         /* Check gzip flags */
 183         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 184             (buf[3] & RESERVED)) {
 185                 DBG_FLT("binfmt_flat: unknown flags?\n");
 186                 goto out_free_buf;
 187         }
 188
 189         ret = 10;
 190         if (buf[3] & EXTRA_FIELD) {
 191                 ret += 2 + buf[10] + (buf[11] << 8);
 192                 if (unlikely(LBUFSIZE == ret)) {
 193                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 194                         goto out_free_buf;
 195                 }
 196         }
 197         if (buf[3] & ORIG_NAME) {
 198                 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
 199                         ;
 200                 if (unlikely(LBUFSIZE == ret)) {
 201                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 202                         goto out_free_buf;
 203                 }
 204         }
 205         if (buf[3] & COMMENT) {
 206                 for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
 207                         ;
 208                 if (unlikely(LBUFSIZE == ret)) {
 209                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 210                         goto out_free_buf;
 211                 }
 212         }
 213
 214         strm.next_in += ret;
 215         strm.avail_in -= ret;
 216
 217         strm.next_out = dst;
 218         strm.avail_out = len;
 219         strm.total_out = 0;
 220
 221         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 222                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 223                 goto out_free_buf;
 224         }
 225
 226         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 227                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 228                 if (ret <= 0)
 229                         break;
 230                 if (is_error(ret)) {
 231                         break;
 232                 }
 233                 len -= ret;
 234
 235                 strm.next_in = buf;
 236                 strm.avail_in = ret;
 237                 strm.total_in = 0;
 238         }
 239
 240         if (ret < 0) {
 241                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 242                         ret, strm.msg);
 243                 goto out_zlib;
 244         }
 245
 246         retval = 0;
 247 out_zlib:
 248         zlib_inflateEnd(&strm);
 249 out_free_buf:
 250         kfree(buf);
 251 out_free:
 252         kfree(strm.workspace);
 253 out:
 254         return retval;
 255 }
 256
 257 #endif /* CONFIG_BINFMT_ZFLAT */
 258
 259 /****************************************************************************/
 260
 261 static abi_ulong
 262 calc_reloc(abi_ulong r, struct lib_info *p, int curid, int internalp)
 263 {
 264     abi_ulong addr;
 265     int id;
 266     abi_ulong start_brk;
 267     abi_ulong start_data;
 268     abi_ulong text_len;
 269     abi_ulong start_code;
 270
 271 #ifdef CONFIG_BINFMT_SHARED_FLAT
 272 #error needs checking
 273     if (r == 0)
 274         id = curid;     /* Relocs of 0 are always self referring */
 275     else {
 276         id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 277         r &= 0x00ffffff;        /* Trim ID off here */
 278     }
 279     if (id >= MAX_SHARED_LIBS) {
 280         fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n",
 281                 (unsigned) r, id);
 282         goto failed;
 283     }
 284     if (curid != id) {
 285         if (internalp) {
 286             fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not "
 287                     "in same module (%d != %d)\n",
 288                     (unsigned) r, curid, id);
 289             goto failed;
 290         } else if (!p[id].loaded && is_error(load_flat_shared_library(id, p))) {
 291             fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id);
 292             goto failed;
 293         }
 294         /* Check versioning information (i.e. time stamps) */
 295         if (p[id].build_date && p[curid].build_date
 296             && p[curid].build_date < p[id].build_date) {
 297             fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n",
 298                     id, curid);
 299             goto failed;
 300         }
 301     }
 302 #else
 303     id = 0;
 304 #endif
 305
 306     start_brk = p[id].start_brk;
 307     start_data = p[id].start_data;
 308     start_code = p[id].start_code;
 309     text_len = p[id].text_len;
 310
 311     if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 312         fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x "
 313                 "(0 - 0x%x/0x%x)\n",
 314                (int) r,(int)(start_brk-start_code),(int)text_len);
 315         goto failed;
 316     }
 317
 318     if (r < text_len)                   /* In text segment */
 319         addr = r + start_code;
 320     else                                        /* In data segment */
 321         addr = r - text_len + start_data;
 322
 323     /* Range checked already above so doing the range tests is redundant...*/
 324     return(addr);
 325
 326 failed:
 327     abort();
 328     return RELOC_FAILED;
 329 }
 330
 331 /****************************************************************************/
 332
 333 /* ??? This does not handle endianness correctly.  */
 334 static void old_reloc(struct lib_info *libinfo, uint32_t rl)
 335 {
 336 #ifdef DEBUG
 337         const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 338 #endif
 339         uint32_t *ptr;
 340         uint32_t offset;
 341         int reloc_type;
 342
 343         offset = rl & 0x3fffffff;
 344         reloc_type = rl >> 30;
 345         /* ??? How to handle this?  */
 346 #if defined(CONFIG_COLDFIRE)
 347         ptr = (uint32_t *) ((unsigned long) libinfo->start_code + offset);
 348 #else
 349         ptr = (uint32_t *) ((unsigned long) libinfo->start_data + offset);
 350 #endif
 351
 352 #ifdef DEBUG
 353         fprintf(stderr, "Relocation of variable at DATASEG+%x "
 354                 "(address %p, currently %x) into segment %s\n",
 355                 offset, ptr, (int)*ptr, segment[reloc_type]);
 356 #endif
 357
 358         switch (reloc_type) {
 359         case OLD_FLAT_RELOC_TYPE_TEXT:
 360                 *ptr += libinfo->start_code;
 361                 break;
 362         case OLD_FLAT_RELOC_TYPE_DATA:
 363                 *ptr += libinfo->start_data;
 364                 break;
 365         case OLD_FLAT_RELOC_TYPE_BSS:
 366                 *ptr += libinfo->end_data;
 367                 break;
 368         default:
 369                 fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n",
 370                         reloc_type);
 371                 break;
 372         }
 373         DBG_FLT("Relocation became %x\n", (int)*ptr);
 374 }
 375
 376 /****************************************************************************/
 377
 378 static int load_flat_file(struct linux_binprm * bprm,
 379                 struct lib_info *libinfo, int id, abi_ulong *extra_stack)
 380 {
 381     struct flat_hdr * hdr;
 382     abi_ulong textpos = 0, datapos = 0;
 383     abi_long result;
 384     abi_ulong realdatastart = 0;
 385     abi_ulong text_len, data_len, bss_len, stack_len, flags;
 386     abi_ulong extra;
 387     abi_ulong reloc = 0, rp;
 388     int i, rev, relocs = 0;
 389     abi_ulong fpos;
 390     abi_ulong start_code;
 391     abi_ulong indx_len;
 392
 393     hdr = ((struct flat_hdr *) bprm->buf);              /* exec-header */
 394
 395     text_len  = ntohl(hdr->data_start);
 396     data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 397     bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 398     stack_len = ntohl(hdr->stack_size);
 399     if (extra_stack) {
 400         stack_len += *extra_stack;
 401         *extra_stack = stack_len;
 402     }
 403     relocs    = ntohl(hdr->reloc_count);
 404     flags     = ntohl(hdr->flags);
 405     rev       = ntohl(hdr->rev);
 406
 407     DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 408
 409     if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 410         fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
 411                 rev, (int) FLAT_VERSION);
 412         return -ENOEXEC;
 413     }
 414
 415     /* Don't allow old format executables to use shared libraries */
 416     if (rev == OLD_FLAT_VERSION && id != 0) {
 417         fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n");
 418         return -ENOEXEC;
 419     }
 420
 421     /*
 422      * fix up the flags for the older format,  there were all kinds
 423      * of endian hacks,  this only works for the simple cases
 424      */
 425     if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 426         flags = FLAT_FLAG_RAM;
 427
 428 #ifndef CONFIG_BINFMT_ZFLAT
 429     if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 430         fprintf(stderr, "Support for ZFLAT executables is not enabled\n");
 431         return -ENOEXEC;
 432     }
 433 #endif
 434
 435     /*
 436      * calculate the extra space we need to map in
 437      */
 438     extra = relocs * sizeof(abi_ulong);
 439     if (extra < bss_len + stack_len)
 440         extra = bss_len + stack_len;
 441
 442     /* Add space for library base pointers.  Make sure this does not
 443        misalign the  doesn't misalign the data segment.  */
 444     indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong);
 445     indx_len = (indx_len + 15) & ~(abi_ulong)15;
 446
 447     /*
 448      * Allocate the address space.
 449      */
 450     probe_guest_base(bprm->filename, 0,
 451                      text_len + data_len + extra + indx_len - 1);
 452
 453     /*
 454      * there are a couple of cases here,  the separate code/data
 455      * case,  and then the fully copied to RAM case which lumps
 456      * it all together.
 457      */
 458     if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 459         /*
 460          * this should give us a ROM ptr,  but if it doesn't we don't
 461          * really care
 462          */
 463         DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 464
 465         textpos = target_mmap(0, text_len, PROT_READ|PROT_EXEC,
 466                               MAP_PRIVATE, bprm->src.fd, 0);
 467         if (textpos == -1) {
 468             fprintf(stderr, "Unable to mmap process text\n");
 469             return -1;
 470         }
 471
 472         realdatastart = target_mmap(0, data_len + extra + indx_len,
 473                                     PROT_READ|PROT_WRITE|PROT_EXEC,
 474                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 475
 476         if (realdatastart == -1) {
 477             fprintf(stderr, "Unable to allocate RAM for process data\n");
 478             return realdatastart;
 479         }
 480         datapos = realdatastart + indx_len;
 481
 482         DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 483                         (int)(data_len + bss_len + stack_len), (int)datapos);
 484
 485         fpos = ntohl(hdr->data_start);
 486 #ifdef CONFIG_BINFMT_ZFLAT
 487         if (flags & FLAT_FLAG_GZDATA) {
 488             result = decompress_exec(bprm, fpos, (char *) datapos,
 489                                      data_len + (relocs * sizeof(abi_ulong)))
 490         } else
 491 #endif
 492         {
 493             result = target_pread(bprm->src.fd, datapos,
 494                                   data_len + (relocs * sizeof(abi_ulong)),
 495                                   fpos);
 496         }
 497         if (result < 0) {
 498             fprintf(stderr, "Unable to read data+bss\n");
 499             return result;
 500         }
 501
 502         reloc = datapos + (ntohl(hdr->reloc_start) - text_len);
 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
 518 #ifdef CONFIG_BINFMT_ZFLAT
 519 #error code needs checking
 520         /*
 521          * load it all in and treat it like a RAM load from now on
 522          */
 523         if (flags & FLAT_FLAG_GZIP) {
 524                 result = decompress_exec(bprm, sizeof (struct flat_hdr),
 525                                  (((char *) textpos) + sizeof (struct flat_hdr)),
 526                                  (text_len + data_len + (relocs * sizeof(unsigned long))
 527                                           - sizeof (struct flat_hdr)),
 528                                  0);
 529                 memmove((void *) datapos, (void *) realdatastart,
 530                                 data_len + (relocs * sizeof(unsigned long)));
 531         } else if (flags & FLAT_FLAG_GZDATA) {
 532                 fpos = 0;
 533                 result = bprm->file->f_op->read(bprm->file,
 534                                 (char *) textpos, text_len, &fpos);
 535                 if (!is_error(result)) {
 536                         result = decompress_exec(bprm, text_len, (char *) datapos,
 537                                          data_len + (relocs * sizeof(unsigned long)), 0);
 538                 }
 539         }
 540         else
 541 #endif
 542         {
 543             result = target_pread(bprm->src.fd, textpos,
 544                                   text_len, 0);
 545             if (result >= 0) {
 546                 result = target_pread(bprm->src.fd, datapos,
 547                     data_len + (relocs * sizeof(abi_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
 564     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 565             id ? "Lib" : "Load", bprm->filename,
 566             (int) start_code, (int) (textpos + text_len),
 567             (int) datapos,
 568             (int) (datapos + data_len),
 569             (int) (datapos + data_len),
 570             (int) (((datapos + data_len + bss_len) + 3) & ~3));
 571
 572     text_len -= sizeof(struct flat_hdr); /* the real code len */
 573
 574     /* Store the current module values into the global library structure */
 575     libinfo[id].start_code = start_code;
 576     libinfo[id].start_data = datapos;
 577     libinfo[id].end_data = datapos + data_len;
 578     libinfo[id].start_brk = datapos + data_len + bss_len;
 579     libinfo[id].text_len = text_len;
 580     libinfo[id].loaded = 1;
 581     libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 582     libinfo[id].build_date = ntohl(hdr->build_date);
 583
 584     /*
 585      * We just load the allocations into some temporary memory to
 586      * help simplify all this mumbo jumbo
 587      *
 588      * We've got two different sections of relocation entries.
 589      * The first is the GOT which resides at the beginning of the data segment
 590      * and is terminated with a -1.  This one can be relocated in place.
 591      * The second is the extra relocation entries tacked after the image's
 592      * data segment. These require a little more processing as the entry is
 593      * really an offset into the image which contains an offset into the
 594      * image.
 595      */
 596     if (flags & FLAT_FLAG_GOTPIC) {
 597         rp = datapos;
 598         while (1) {
 599             abi_ulong addr;
 600             if (get_user_ual(addr, rp))
 601                 return -EFAULT;
 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                 if (put_user_ual(addr, rp))
 609                     return -EFAULT;
 610             }
 611             rp += sizeof(abi_ulong);
 612         }
 613     }
 614
 615     /*
 616      * Now run through the relocation entries.
 617      * We've got to be careful here as C++ produces relocatable zero
 618      * entries in the constructor and destructor tables which are then
 619      * tested for being not zero (which will always occur unless we're
 620      * based from address zero).  This causes an endless loop as __start
 621      * is at zero.  The solution used is to not relocate zero addresses.
 622      * This has the negative side effect of not allowing a global data
 623      * reference to be statically initialised to _stext (I've moved
 624      * __start to address 4 so that is okay).
 625      */
 626     if (rev > OLD_FLAT_VERSION) {
 627         abi_ulong persistent = 0;
 628         for (i = 0; i < relocs; i++) {
 629             abi_ulong addr, relval;
 630
 631             /* Get the address of the pointer to be
 632                relocated (of course, the address has to be
 633                relocated first).  */
 634             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 635                 return -EFAULT;
 636             relval = ntohl(relval);
 637             if (flat_set_persistent(relval, &persistent))
 638                 continue;
 639             addr = flat_get_relocate_addr(relval);
 640             rp = calc_reloc(addr, libinfo, id, 1);
 641             if (rp == RELOC_FAILED)
 642                 return -ENOEXEC;
 643
 644             /* Get the pointer's value.  */
 645             if (get_user_ual(addr, rp))
 646                 return -EFAULT;
 647             addr = flat_get_addr_from_rp(addr, relval, flags, &persistent);
 648             if (addr != 0) {
 649                 /*
 650                  * Do the relocation.  PIC relocs in the data section are
 651                  * already in target order
 652                  */
 653                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 654                     addr = ntohl(addr);
 655                 addr = calc_reloc(addr, libinfo, id, 0);
 656                 if (addr == RELOC_FAILED)
 657                     return -ENOEXEC;
 658
 659                 /* Write back the relocated pointer.  */
 660                 if (flat_put_addr_at_rp(rp, addr, relval))
 661                     return -EFAULT;
 662             }
 663         }
 664     } else {
 665         for (i = 0; i < relocs; i++) {
 666             abi_ulong relval;
 667             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 668                 return -EFAULT;
 669             old_reloc(&libinfo[0], relval);
 670         }
 671     }
 672
 673     /* zero the BSS.  */
 674     memset(g2h_untagged(datapos + data_len), 0, bss_len);
 675
 676     return 0;
 677 }
 678
 679
 680 /****************************************************************************/
 681 #ifdef CONFIG_BINFMT_SHARED_FLAT
 682
 683 /*
 684  * Load a shared library into memory.  The library gets its own data
 685  * segment (including bss) but not argv/argc/environ.
 686  */
 687
 688 static int load_flat_shared_library(int id, struct lib_info *libs)
 689 {
 690         struct linux_binprm bprm;
 691         int res;
 692         char buf[16];
 693
 694         /* Create the file name */
 695         sprintf(buf, "/lib/lib%d.so", id);
 696
 697         /* Open the file up */
 698         bprm.filename = buf;
 699         bprm.file = open_exec(bprm.filename);
 700         res = PTR_ERR(bprm.file);
 701         if (IS_ERR(bprm.file))
 702                 return res;
 703
 704         res = prepare_binprm(&bprm);
 705
 706         if (!is_error(res)) {
 707                 res = load_flat_file(&bprm, libs, id, NULL);
 708         }
 709         if (bprm.file) {
 710                 allow_write_access(bprm.file);
 711                 fput(bprm.file);
 712                 bprm.file = NULL;
 713         }
 714         return(res);
 715 }
 716
 717 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 718
 719 int load_flt_binary(struct linux_binprm *bprm, struct image_info *info)
 720 {
 721     struct lib_info libinfo[MAX_SHARED_LIBS];
 722     abi_ulong p;
 723     abi_ulong stack_len;
 724     abi_ulong start_addr;
 725     abi_ulong sp;
 726     int res;
 727     int i, j;
 728
 729     memset(libinfo, 0, sizeof(libinfo));
 730     /*
 731      * We have to add the size of our arguments to our stack size
 732      * otherwise it's too easy for users to create stack overflows
 733      * by passing in a huge argument list.  And yes,  we have to be
 734      * pedantic and include space for the argv/envp array as it may have
 735      * a lot of entries.
 736      */
 737     stack_len = 0;
 738     for (i = 0; i < bprm->argc; ++i) {
 739         /* the argv strings */
 740         stack_len += strlen(bprm->argv[i]);
 741     }
 742     for (i = 0; i < bprm->envc; ++i) {
 743         /* the envp strings */
 744         stack_len += strlen(bprm->envp[i]);
 745     }
 746     stack_len += (bprm->argc + 1) * 4; /* the argv array */
 747     stack_len += (bprm->envc + 1) * 4; /* the envp array */
 748
 749
 750     res = load_flat_file(bprm, libinfo, 0, &stack_len);
 751     if (is_error(res)) {
 752             return res;
 753     }
 754
 755     /* Update data segment pointers for all libraries */
 756     for (i=0; i<MAX_SHARED_LIBS; i++) {
 757         if (libinfo[i].loaded) {
 758             abi_ulong seg;
 759             seg = libinfo[i].start_data;
 760             for (j=0; j<MAX_SHARED_LIBS; j++) {
 761                 seg -= 4;
 762                 /* FIXME - handle put_user() failures */
 763                 if (put_user_ual(libinfo[j].loaded
 764                                  ? libinfo[j].start_data
 765                                  : UNLOADED_LIB,
 766                                  seg))
 767                     return -EFAULT;
 768             }
 769         }
 770     }
 771
 772     p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4;
 773     DBG_FLT("p=%x\n", (int)p);
 774
 775     /* Copy argv/envp.  */
 776     p = copy_strings(p, bprm->envc, bprm->envp);
 777     p = copy_strings(p, bprm->argc, bprm->argv);
 778     /* Align stack.  */
 779     sp = p & ~(abi_ulong)(sizeof(abi_ulong) - 1);
 780     /* Enforce final stack alignment of 16 bytes.  This is sufficient
 781        for all current targets, and excess alignment is harmless.  */
 782     stack_len = bprm->envc + bprm->argc + 2;
 783     stack_len += flat_argvp_envp_on_stack() ? 2 : 0; /* argv, argp */
 784     stack_len += 1; /* argc */
 785     stack_len *= sizeof(abi_ulong);
 786     sp -= (sp - stack_len) & 15;
 787     sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p,
 788                              flat_argvp_envp_on_stack());
 789
 790     /* Fake some return addresses to ensure the call chain will
 791      * initialise library in order for us.  We are required to call
 792      * lib 1 first, then 2, ... and finally the main program (id 0).
 793      */
 794     start_addr = libinfo[0].entry;
 795
 796 #ifdef CONFIG_BINFMT_SHARED_FLAT
 797 #error here
 798     for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 799             if (libinfo[i].loaded) {
 800                     /* Push previous first to call address */
 801                     --sp;
 802                     if (put_user_ual(start_addr, sp))
 803                         return -EFAULT;
 804                     start_addr = libinfo[i].entry;
 805             }
 806     }
 807 #endif
 808
 809     /* Stash our initial stack pointer into the mm structure */
 810     info->start_code = libinfo[0].start_code;
 811     info->end_code = libinfo[0].start_code + libinfo[0].text_len;
 812     info->start_data = libinfo[0].start_data;
 813     info->end_data = libinfo[0].end_data;
 814     info->brk = libinfo[0].start_brk;
 815     info->start_stack = sp;
 816     info->stack_limit = libinfo[0].start_brk;
 817     info->entry = start_addr;
 818     info->code_offset = info->start_code;
 819     info->data_offset = info->start_data - libinfo[0].text_len;
 820
 821     DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n",
 822             (int)info->entry, (int)info->start_stack);
 823
 824     return 0;
 825 }