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 "loader.h"
  40 #include "user-mmap.h"
  41 #include "flat.h"
  42 #include "target_flat.h"
  43
  44 //#define DEBUG
  45
  46 #ifdef DEBUG
  47 #define DBG_FLT(...)    printf(__VA_ARGS__)
  48 #else
  49 #define DBG_FLT(...)
  50 #endif
  51
  52 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  53 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  54
  55 struct lib_info {
  56     abi_ulong start_code;       /* Start of text segment */
  57     abi_ulong start_data;       /* Start of data segment */
  58     abi_ulong end_data;         /* Start of bss section */
  59     abi_ulong start_brk;        /* End of data segment */
  60     abi_ulong text_len;         /* Length of text segment */
  61     abi_ulong entry;            /* Start address for this module */
  62     abi_ulong build_date;       /* When this one was compiled */
  63     short loaded;               /* Has this library been loaded? */
  64 };
  65
  66 #ifdef CONFIG_BINFMT_SHARED_FLAT
  67 static int load_flat_shared_library(int id, struct lib_info *p);
  68 #endif
  69
  70 struct linux_binprm;
  71
  72 /****************************************************************************/
  73 /*
  74  * create_flat_tables() parses the env- and arg-strings in new user
  75  * memory and creates the pointer tables from them, and puts their
  76  * addresses on the "stack", returning the new stack pointer value.
  77  */
  78
  79 /* Push a block of strings onto the guest stack.  */
  80 static abi_ulong copy_strings(abi_ulong p, int n, char **s)
  81 {
  82     int len;
  83
  84     while (n-- > 0) {
  85         len = strlen(s[n]) + 1;
  86         p -= len;
  87         memcpy_to_target(p, s[n], len);
  88     }
  89
  90     return p;
  91 }
  92
  93 static int target_pread(int fd, abi_ulong ptr, abi_ulong len,
  94                         abi_ulong offset)
  95 {
  96     void *buf;
  97     int ret;
  98
  99     buf = lock_user(VERIFY_WRITE, ptr, len, 0);
 100     if (!buf) {
 101         return -EFAULT;
 102     }
 103     ret = pread(fd, buf, len, offset);
 104     if (ret < 0) {
 105         ret = -errno;
 106     }
 107     unlock_user(buf, ptr, len);
 108     return ret;
 109 }
 110 /****************************************************************************/
 111
 112 #ifdef CONFIG_BINFMT_ZFLAT
 113
 114 #include <linux/zlib.h>
 115
 116 #define LBUFSIZE        4000
 117
 118 /* gzip flag byte */
 119 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 120 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 121 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 122 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 123 #define COMMENT      0x10 /* bit 4 set: file comment present */
 124 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 125 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 126
 127 static int decompress_exec(
 128         struct linux_binprm *bprm,
 129         unsigned long offset,
 130         char *dst,
 131         long len,
 132         int fd)
 133 {
 134         unsigned char *buf;
 135         z_stream strm;
 136         loff_t fpos;
 137         int ret, retval;
 138
 139         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 140
 141         memset(&strm, 0, sizeof(strm));
 142         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 143         if (strm.workspace == NULL) {
 144                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 145                 return -ENOMEM;
 146         }
 147         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 148         if (buf == NULL) {
 149                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 150                 retval = -ENOMEM;
 151                 goto out_free;
 152         }
 153
 154         /* Read in first chunk of data and parse gzip header. */
 155         fpos = offset;
 156         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 157
 158         strm.next_in = buf;
 159         strm.avail_in = ret;
 160         strm.total_in = 0;
 161
 162         retval = -ENOEXEC;
 163
 164         /* Check minimum size -- gzip header */
 165         if (ret < 10) {
 166                 DBG_FLT("binfmt_flat: file too small?\n");
 167                 goto out_free_buf;
 168         }
 169
 170         /* Check gzip magic number */
 171         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 172                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 173                 goto out_free_buf;
 174         }
 175
 176         /* Check gzip method */
 177         if (buf[2] != 8) {
 178                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 179                 goto out_free_buf;
 180         }
 181         /* Check gzip flags */
 182         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 183             (buf[3] & RESERVED)) {
 184                 DBG_FLT("binfmt_flat: unknown flags?\n");
 185                 goto out_free_buf;
 186         }
 187
 188         ret = 10;
 189         if (buf[3] & EXTRA_FIELD) {
 190                 ret += 2 + buf[10] + (buf[11] << 8);
 191                 if (unlikely(LBUFSIZE == ret)) {
 192                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 193                         goto out_free_buf;
 194                 }
 195         }
 196         if (buf[3] & ORIG_NAME) {
 197                 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
 198                         ;
 199                 if (unlikely(LBUFSIZE == ret)) {
 200                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 201                         goto out_free_buf;
 202                 }
 203         }
 204         if (buf[3] & COMMENT) {
 205                 for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
 206                         ;
 207                 if (unlikely(LBUFSIZE == ret)) {
 208                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 209                         goto out_free_buf;
 210                 }
 211         }
 212
 213         strm.next_in += ret;
 214         strm.avail_in -= ret;
 215
 216         strm.next_out = dst;
 217         strm.avail_out = len;
 218         strm.total_out = 0;
 219
 220         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 221                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 222                 goto out_free_buf;
 223         }
 224
 225         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 226                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 227                 if (ret <= 0)
 228                         break;
 229                 if (is_error(ret)) {
 230                         break;
 231                 }
 232                 len -= ret;
 233
 234                 strm.next_in = buf;
 235                 strm.avail_in = ret;
 236                 strm.total_in = 0;
 237         }
 238
 239         if (ret < 0) {
 240                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 241                         ret, strm.msg);
 242                 goto out_zlib;
 243         }
 244
 245         retval = 0;
 246 out_zlib:
 247         zlib_inflateEnd(&strm);
 248 out_free_buf:
 249         kfree(buf);
 250 out_free:
 251         kfree(strm.workspace);
 252 out:
 253         return retval;
 254 }
 255
 256 #endif /* CONFIG_BINFMT_ZFLAT */
 257
 258 /****************************************************************************/
 259
 260 static abi_ulong
 261 calc_reloc(abi_ulong r, struct lib_info *p, int curid, int internalp)
 262 {
 263     abi_ulong addr;
 264     int id;
 265     abi_ulong start_brk;
 266     abi_ulong start_data;
 267     abi_ulong text_len;
 268     abi_ulong start_code;
 269
 270 #ifdef CONFIG_BINFMT_SHARED_FLAT
 271 #error needs checking
 272     if (r == 0)
 273         id = curid;     /* Relocs of 0 are always self referring */
 274     else {
 275         id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 276         r &= 0x00ffffff;        /* Trim ID off here */
 277     }
 278     if (id >= MAX_SHARED_LIBS) {
 279         fprintf(stderr, "BINFMT_FLAT: reference 0x%x to shared library %d\n",
 280                 (unsigned) r, id);
 281         goto failed;
 282     }
 283     if (curid != id) {
 284         if (internalp) {
 285             fprintf(stderr, "BINFMT_FLAT: reloc address 0x%x not "
 286                     "in same module (%d != %d)\n",
 287                     (unsigned) r, curid, id);
 288             goto failed;
 289         } else if (!p[id].loaded && is_error(load_flat_shared_library(id, p))) {
 290             fprintf(stderr, "BINFMT_FLAT: failed to load library %d\n", id);
 291             goto failed;
 292         }
 293         /* Check versioning information (i.e. time stamps) */
 294         if (p[id].build_date && p[curid].build_date
 295             && p[curid].build_date < p[id].build_date) {
 296             fprintf(stderr, "BINFMT_FLAT: library %d is younger than %d\n",
 297                     id, curid);
 298             goto failed;
 299         }
 300     }
 301 #else
 302     id = 0;
 303 #endif
 304
 305     start_brk = p[id].start_brk;
 306     start_data = p[id].start_data;
 307     start_code = p[id].start_code;
 308     text_len = p[id].text_len;
 309
 310     if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 311         fprintf(stderr, "BINFMT_FLAT: reloc outside program 0x%x "
 312                 "(0 - 0x%x/0x%x)\n",
 313                (int) r,(int)(start_brk-start_code),(int)text_len);
 314         goto failed;
 315     }
 316
 317     if (r < text_len)                   /* In text segment */
 318         addr = r + start_code;
 319     else                                        /* In data segment */
 320         addr = r - text_len + start_data;
 321
 322     /* Range checked already above so doing the range tests is redundant...*/
 323     return(addr);
 324
 325 failed:
 326     abort();
 327     return RELOC_FAILED;
 328 }
 329
 330 /****************************************************************************/
 331
 332 /* ??? This does not handle endianness correctly.  */
 333 static void old_reloc(struct lib_info *libinfo, uint32_t rl)
 334 {
 335 #ifdef DEBUG
 336         const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 337 #endif
 338         uint32_t *ptr;
 339         uint32_t offset;
 340         int reloc_type;
 341
 342         offset = rl & 0x3fffffff;
 343         reloc_type = rl >> 30;
 344         /* ??? How to handle this?  */
 345 #if defined(CONFIG_COLDFIRE)
 346         ptr = (uint32_t *) ((unsigned long) libinfo->start_code + offset);
 347 #else
 348         ptr = (uint32_t *) ((unsigned long) libinfo->start_data + offset);
 349 #endif
 350
 351 #ifdef DEBUG
 352         fprintf(stderr, "Relocation of variable at DATASEG+%x "
 353                 "(address %p, currently %x) into segment %s\n",
 354                 offset, ptr, (int)*ptr, segment[reloc_type]);
 355 #endif
 356
 357         switch (reloc_type) {
 358         case OLD_FLAT_RELOC_TYPE_TEXT:
 359                 *ptr += libinfo->start_code;
 360                 break;
 361         case OLD_FLAT_RELOC_TYPE_DATA:
 362                 *ptr += libinfo->start_data;
 363                 break;
 364         case OLD_FLAT_RELOC_TYPE_BSS:
 365                 *ptr += libinfo->end_data;
 366                 break;
 367         default:
 368                 fprintf(stderr, "BINFMT_FLAT: Unknown relocation type=%x\n",
 369                         reloc_type);
 370                 break;
 371         }
 372         DBG_FLT("Relocation became %x\n", (int)*ptr);
 373 }
 374
 375 /****************************************************************************/
 376
 377 static int load_flat_file(struct linux_binprm * bprm,
 378                 struct lib_info *libinfo, int id, abi_ulong *extra_stack)
 379 {
 380     struct flat_hdr * hdr;
 381     abi_ulong textpos = 0, datapos = 0;
 382     abi_long result;
 383     abi_ulong realdatastart = 0;
 384     abi_ulong text_len, data_len, bss_len, stack_len, flags;
 385     abi_ulong extra;
 386     abi_ulong reloc = 0, rp;
 387     int i, rev, relocs = 0;
 388     abi_ulong fpos;
 389     abi_ulong start_code;
 390     abi_ulong indx_len;
 391
 392     hdr = ((struct flat_hdr *) bprm->buf);              /* exec-header */
 393
 394     text_len  = ntohl(hdr->data_start);
 395     data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 396     bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 397     stack_len = ntohl(hdr->stack_size);
 398     if (extra_stack) {
 399         stack_len += *extra_stack;
 400         *extra_stack = stack_len;
 401     }
 402     relocs    = ntohl(hdr->reloc_count);
 403     flags     = ntohl(hdr->flags);
 404     rev       = ntohl(hdr->rev);
 405
 406     DBG_FLT("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 407
 408     if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 409         fprintf(stderr, "BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
 410                 rev, (int) FLAT_VERSION);
 411         return -ENOEXEC;
 412     }
 413
 414     /* Don't allow old format executables to use shared libraries */
 415     if (rev == OLD_FLAT_VERSION && id != 0) {
 416         fprintf(stderr, "BINFMT_FLAT: shared libraries are not available\n");
 417         return -ENOEXEC;
 418     }
 419
 420     /*
 421      * fix up the flags for the older format,  there were all kinds
 422      * of endian hacks,  this only works for the simple cases
 423      */
 424     if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 425         flags = FLAT_FLAG_RAM;
 426
 427 #ifndef CONFIG_BINFMT_ZFLAT
 428     if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 429         fprintf(stderr, "Support for ZFLAT executables is not enabled\n");
 430         return -ENOEXEC;
 431     }
 432 #endif
 433
 434     /*
 435      * calculate the extra space we need to map in
 436      */
 437     extra = relocs * sizeof(abi_ulong);
 438     if (extra < bss_len + stack_len)
 439         extra = bss_len + stack_len;
 440
 441     /* Add space for library base pointers.  Make sure this does not
 442        misalign the  doesn't misalign the data segment.  */
 443     indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong);
 444     indx_len = (indx_len + 15) & ~(abi_ulong)15;
 445
 446     /*
 447      * Allocate the address space.
 448      */
 449     probe_guest_base(bprm->filename, 0,
 450                      text_len + data_len + extra + indx_len);
 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(abi_ulong)))
 489         } else
 490 #endif
 491         {
 492             result = target_pread(bprm->fd, datapos,
 493                                   data_len + (relocs * sizeof(abi_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
 503     } else {
 504
 505         textpos = target_mmap(0, text_len + data_len + extra + indx_len,
 506                               PROT_READ | PROT_EXEC | PROT_WRITE,
 507                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 508         if (textpos == -1 ) {
 509             fprintf(stderr, "Unable to allocate RAM for process text/data\n");
 510             return -1;
 511         }
 512
 513         realdatastart = textpos + ntohl(hdr->data_start);
 514         datapos = realdatastart + indx_len;
 515         reloc = (textpos + ntohl(hdr->reloc_start) + indx_len);
 516
 517 #ifdef CONFIG_BINFMT_ZFLAT
 518 #error code needs checking
 519         /*
 520          * load it all in and treat it like a RAM load from now on
 521          */
 522         if (flags & FLAT_FLAG_GZIP) {
 523                 result = decompress_exec(bprm, sizeof (struct flat_hdr),
 524                                  (((char *) textpos) + sizeof (struct flat_hdr)),
 525                                  (text_len + data_len + (relocs * sizeof(unsigned long))
 526                                           - sizeof (struct flat_hdr)),
 527                                  0);
 528                 memmove((void *) datapos, (void *) realdatastart,
 529                                 data_len + (relocs * sizeof(unsigned long)));
 530         } else if (flags & FLAT_FLAG_GZDATA) {
 531                 fpos = 0;
 532                 result = bprm->file->f_op->read(bprm->file,
 533                                 (char *) textpos, text_len, &fpos);
 534                 if (!is_error(result)) {
 535                         result = decompress_exec(bprm, text_len, (char *) datapos,
 536                                          data_len + (relocs * sizeof(unsigned long)), 0);
 537                 }
 538         }
 539         else
 540 #endif
 541         {
 542             result = target_pread(bprm->fd, textpos,
 543                                   text_len, 0);
 544             if (result >= 0) {
 545                 result = target_pread(bprm->fd, datapos,
 546                     data_len + (relocs * sizeof(abi_ulong)),
 547                     ntohl(hdr->data_start));
 548             }
 549         }
 550         if (result < 0) {
 551             fprintf(stderr, "Unable to read code+data+bss\n");
 552             return result;
 553         }
 554     }
 555
 556     DBG_FLT("Mapping is 0x%x, Entry point is 0x%x, data_start is 0x%x\n",
 557             (int)textpos, 0x00ffffff&ntohl(hdr->entry),
 558             ntohl(hdr->data_start));
 559
 560     /* The main program needs a little extra setup in the task structure */
 561     start_code = textpos + sizeof (struct flat_hdr);
 562
 563     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 564             id ? "Lib" : "Load", bprm->filename,
 565             (int) start_code, (int) (textpos + text_len),
 566             (int) datapos,
 567             (int) (datapos + data_len),
 568             (int) (datapos + data_len),
 569             (int) (((datapos + data_len + bss_len) + 3) & ~3));
 570
 571     text_len -= sizeof(struct flat_hdr); /* the real code len */
 572
 573     /* Store the current module values into the global library structure */
 574     libinfo[id].start_code = start_code;
 575     libinfo[id].start_data = datapos;
 576     libinfo[id].end_data = datapos + data_len;
 577     libinfo[id].start_brk = datapos + data_len + bss_len;
 578     libinfo[id].text_len = text_len;
 579     libinfo[id].loaded = 1;
 580     libinfo[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 581     libinfo[id].build_date = ntohl(hdr->build_date);
 582
 583     /*
 584      * We just load the allocations into some temporary memory to
 585      * help simplify all this mumbo jumbo
 586      *
 587      * We've got two different sections of relocation entries.
 588      * The first is the GOT which resides at the beginning of the data segment
 589      * and is terminated with a -1.  This one can be relocated in place.
 590      * The second is the extra relocation entries tacked after the image's
 591      * data segment. These require a little more processing as the entry is
 592      * really an offset into the image which contains an offset into the
 593      * image.
 594      */
 595     if (flags & FLAT_FLAG_GOTPIC) {
 596         rp = datapos;
 597         while (1) {
 598             abi_ulong addr;
 599             if (get_user_ual(addr, rp))
 600                 return -EFAULT;
 601             if (addr == -1)
 602                 break;
 603             if (addr) {
 604                 addr = calc_reloc(addr, libinfo, id, 0);
 605                 if (addr == RELOC_FAILED)
 606                     return -ENOEXEC;
 607                 if (put_user_ual(addr, rp))
 608                     return -EFAULT;
 609             }
 610             rp += sizeof(abi_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         abi_ulong persistent = 0;
 627         for (i = 0; i < relocs; i++) {
 628             abi_ulong addr, relval;
 629
 630             /* Get the address of the pointer to be
 631                relocated (of course, the address has to be
 632                relocated first).  */
 633             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 634                 return -EFAULT;
 635             relval = ntohl(relval);
 636             if (flat_set_persistent(relval, &persistent))
 637                 continue;
 638             addr = flat_get_relocate_addr(relval);
 639             rp = calc_reloc(addr, libinfo, id, 1);
 640             if (rp == RELOC_FAILED)
 641                 return -ENOEXEC;
 642
 643             /* Get the pointer's value.  */
 644             if (get_user_ual(addr, rp))
 645                 return -EFAULT;
 646             addr = flat_get_addr_from_rp(addr, relval, flags, &persistent);
 647             if (addr != 0) {
 648                 /*
 649                  * Do the relocation.  PIC relocs in the data section are
 650                  * already in target order
 651                  */
 652                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 653                     addr = ntohl(addr);
 654                 addr = calc_reloc(addr, libinfo, id, 0);
 655                 if (addr == RELOC_FAILED)
 656                     return -ENOEXEC;
 657
 658                 /* Write back the relocated pointer.  */
 659                 if (flat_put_addr_at_rp(rp, addr, relval))
 660                     return -EFAULT;
 661             }
 662         }
 663     } else {
 664         for (i = 0; i < relocs; i++) {
 665             abi_ulong relval;
 666             if (get_user_ual(relval, reloc + i * sizeof(abi_ulong)))
 667                 return -EFAULT;
 668             old_reloc(&libinfo[0], relval);
 669         }
 670     }
 671
 672     /* zero the BSS.  */
 673     memset(g2h_untagged(datapos + data_len), 0, bss_len);
 674
 675     return 0;
 676 }
 677
 678
 679 /****************************************************************************/
 680 #ifdef CONFIG_BINFMT_SHARED_FLAT
 681
 682 /*
 683  * Load a shared library into memory.  The library gets its own data
 684  * segment (including bss) but not argv/argc/environ.
 685  */
 686
 687 static int load_flat_shared_library(int id, struct lib_info *libs)
 688 {
 689         struct linux_binprm bprm;
 690         int res;
 691         char buf[16];
 692
 693         /* Create the file name */
 694         sprintf(buf, "/lib/lib%d.so", id);
 695
 696         /* Open the file up */
 697         bprm.filename = buf;
 698         bprm.file = open_exec(bprm.filename);
 699         res = PTR_ERR(bprm.file);
 700         if (IS_ERR(bprm.file))
 701                 return res;
 702
 703         res = prepare_binprm(&bprm);
 704
 705         if (!is_error(res)) {
 706                 res = load_flat_file(&bprm, libs, id, NULL);
 707         }
 708         if (bprm.file) {
 709                 allow_write_access(bprm.file);
 710                 fput(bprm.file);
 711                 bprm.file = NULL;
 712         }
 713         return(res);
 714 }
 715
 716 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 717
 718 int load_flt_binary(struct linux_binprm *bprm, struct image_info *info)
 719 {
 720     struct lib_info libinfo[MAX_SHARED_LIBS];
 721     abi_ulong p;
 722     abi_ulong stack_len;
 723     abi_ulong start_addr;
 724     abi_ulong sp;
 725     int res;
 726     int i, j;
 727
 728     memset(libinfo, 0, sizeof(libinfo));
 729     /*
 730      * We have to add the size of our arguments to our stack size
 731      * otherwise it's too easy for users to create stack overflows
 732      * by passing in a huge argument list.  And yes,  we have to be
 733      * pedantic and include space for the argv/envp array as it may have
 734      * a lot of entries.
 735      */
 736     stack_len = 0;
 737     for (i = 0; i < bprm->argc; ++i) {
 738         /* the argv strings */
 739         stack_len += strlen(bprm->argv[i]);
 740     }
 741     for (i = 0; i < bprm->envc; ++i) {
 742         /* the envp strings */
 743         stack_len += strlen(bprm->envp[i]);
 744     }
 745     stack_len += (bprm->argc + 1) * 4; /* the argv array */
 746     stack_len += (bprm->envc + 1) * 4; /* the envp array */
 747
 748
 749     res = load_flat_file(bprm, libinfo, 0, &stack_len);
 750     if (is_error(res)) {
 751             return res;
 752     }
 753
 754     /* Update data segment pointers for all libraries */
 755     for (i=0; i<MAX_SHARED_LIBS; i++) {
 756         if (libinfo[i].loaded) {
 757             abi_ulong p;
 758             p = libinfo[i].start_data;
 759             for (j=0; j<MAX_SHARED_LIBS; j++) {
 760                 p -= 4;
 761                 /* FIXME - handle put_user() failures */
 762                 if (put_user_ual(libinfo[j].loaded
 763                                  ? libinfo[j].start_data
 764                                  : UNLOADED_LIB,
 765                                  p))
 766                     return -EFAULT;
 767             }
 768         }
 769     }
 770
 771     p = ((libinfo[0].start_brk + stack_len + 3) & ~3) - 4;
 772     DBG_FLT("p=%x\n", (int)p);
 773
 774     /* Copy argv/envp.  */
 775     p = copy_strings(p, bprm->envc, bprm->envp);
 776     p = copy_strings(p, bprm->argc, bprm->argv);
 777     /* Align stack.  */
 778     sp = p & ~(abi_ulong)(sizeof(abi_ulong) - 1);
 779     /* Enforce final stack alignment of 16 bytes.  This is sufficient
 780        for all current targets, and excess alignment is harmless.  */
 781     stack_len = bprm->envc + bprm->argc + 2;
 782     stack_len += flat_argvp_envp_on_stack() ? 2 : 0; /* arvg, argp */
 783     stack_len += 1; /* argc */
 784     stack_len *= sizeof(abi_ulong);
 785     sp -= (sp - stack_len) & 15;
 786     sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p,
 787                              flat_argvp_envp_on_stack());
 788
 789     /* Fake some return addresses to ensure the call chain will
 790      * initialise library in order for us.  We are required to call
 791      * lib 1 first, then 2, ... and finally the main program (id 0).
 792      */
 793     start_addr = libinfo[0].entry;
 794
 795 #ifdef CONFIG_BINFMT_SHARED_FLAT
 796 #error here
 797     for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 798             if (libinfo[i].loaded) {
 799                     /* Push previous first to call address */
 800                     --sp;
 801                     if (put_user_ual(start_addr, sp))
 802                         return -EFAULT;
 803                     start_addr = libinfo[i].entry;
 804             }
 805     }
 806 #endif
 807
 808     /* Stash our initial stack pointer into the mm structure */
 809     info->start_code = libinfo[0].start_code;
 810     info->end_code = libinfo[0].start_code = libinfo[0].text_len;
 811     info->start_data = libinfo[0].start_data;
 812     info->end_data = libinfo[0].end_data;
 813     info->start_brk = libinfo[0].start_brk;
 814     info->start_stack = sp;
 815     info->stack_limit = libinfo[0].start_brk;
 816     info->entry = start_addr;
 817     info->code_offset = info->start_code;
 818     info->data_offset = info->start_data - libinfo[0].text_len;
 819
 820     DBG_FLT("start_thread(entry=0x%x, start_stack=0x%x)\n",
 821             (int)info->entry, (int)info->start_stack);
 822
 823     return 0;
 824 }