loader/preloader.c

   1 /*
   2  * Preloader for ld.so
   3  *
   4  * Copyright (C) 1995,96,97,98,99,2000,2001,2002 Free Software Foundation, Inc.
   5  * Copyright (C) 2004 Mike McCormack for CodeWeavers
   6  * Copyright (C) 2004 Alexandre Julliard
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 /*
  24  * Design notes
  25  *
  26  * The goal of this program is to be a workaround for exec-shield, as used
  27  *  by the Linux kernel distributed with Fedora Core and other distros.
  28  *
  29  * To do this, we implement our own shared object loader that reserves memory
  30  * that is important to Wine, and then loads the main binary and its ELF
  31  * interpreter.
  32  *
  33  * We will try to set up the stack and memory area so that the program that
  34  * loads after us (eg. the wine binary) never knows we were here, except that
  35  * areas of memory it needs are already magically reserved.
  36  *
  37  * The following memory areas are important to Wine:
  38  *  0x00000000 - 0x00110000  the DOS area
  39  *  0x80000000 - 0x81000000  the shared heap
  40  *  ???        - ???         the PE binary load address (usually starting at 0x00400000)
  41  *
  42  * If this program is used as the shared object loader, the only difference
  43  * that the loaded programs should see is that this loader will be mapped
  44  * into memory when it starts.
  45  */
  46
  47 /*
  48  * References (things I consulted to understand how ELF loading works):
  49  *
  50  * glibc 2.3.2   elf/dl-load.c
  51  *  http://www.gnu.org/directory/glibc.html
  52  *
  53  * Linux 2.6.4   fs/binfmt_elf.c
  54  *  ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.4.tar.bz2
  55  *
  56  * Userland exec, by <grugq@hcunix.net>
  57  *  http://cert.uni-stuttgart.de/archive/bugtraq/2004/01/msg00002.html
  58  *
  59  * The ELF specification:
  60  *  http://www.linuxbase.org/spec/booksets/LSB-Embedded/LSB-Embedded/book387.html
  61  */
  62
  63 #include "config.h"
  64 #include "wine/port.h"
  65
  66 #include <stdarg.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70 #include <sys/types.h>
  71 #include <sys/stat.h>
  72 #include <fcntl.h>
  73 #ifdef HAVE_SYS_MMAN_H
  74 # include <sys/mman.h>
  75 #endif
  76 #ifdef HAVE_SYS_SYSCALL_H
  77 # include <sys/syscall.h>
  78 #endif
  79 #ifdef HAVE_UNISTD_H
  80 # include <unistd.h>
  81 #endif
  82 #ifdef HAVE_ELF_H
  83 # include <elf.h>
  84 #endif
  85 #ifdef HAVE_LINK_H
  86 # include <link.h>
  87 #endif
  88 #ifdef HAVE_SYS_LINK_H
  89 # include <sys/link.h>
  90 #endif
  91
  92 #include "main.h"
  93
  94 /* ELF definitions */
  95 #define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
  96 #define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
  97
  98 #define MAP_BASE_ADDR(l)     0
  99
 100 #ifndef MAP_COPY
 101 #define MAP_COPY MAP_PRIVATE
 102 #endif
 103 #ifndef MAP_NORESERVE
 104 #define MAP_NORESERVE 0
 105 #endif
 106
 107 static struct wine_preload_info preload_info[] =
 108 {
 109     { (void *)0x00000000, 0x00110000 },  /* DOS area */
 110     { (void *)0x80000000, 0x01000000 },  /* shared heap */
 111     { (void *)0x00110000, 0x0fef0000 },  /* default PE exe range (may be set with WINEPRELOADRESERVE) */
 112     { 0, 0 }                             /* end of list */
 113 };
 114
 115 /* debugging */
 116 #undef DUMP_SEGMENTS
 117 #undef DUMP_AUX_INFO
 118 #undef DUMP_SYMS
 119
 120 /* older systems may not define these */
 121 #ifndef PT_TLS
 122 #define PT_TLS 7
 123 #endif
 124
 125 #ifndef AT_SYSINFO
 126 #define AT_SYSINFO 32
 127 #endif
 128 #ifndef AT_SYSINFO_EHDR
 129 #define AT_SYSINFO_EHDR 33
 130 #endif
 131
 132 static unsigned int page_size, page_mask;
 133 static char *preloader_start, *preloader_end;
 134
 135 struct wld_link_map {
 136     ElfW(Addr) l_addr;
 137     ElfW(Dyn) *l_ld;
 138     ElfW(Phdr)*l_phdr;
 139     ElfW(Addr) l_entry;
 140     ElfW(Half) l_ldnum;
 141     ElfW(Half) l_phnum;
 142     ElfW(Addr) l_map_start, l_map_end;
 143     ElfW(Addr) l_interp;
 144 };
 145
 146
 147 /*
 148  * The _start function is the entry and exit point of this program
 149  *
 150  *  It calls wld_start, passing a pointer to the args it receives
 151  *  then jumps to the address wld_start returns.
 152  */
 153 void _start();
 154 extern char _end[];
 155 __ASM_GLOBAL_FUNC(_start,
 156                   "\tmovl %esp,%eax\n"
 157                   "\tleal -128(%esp),%esp\n"  /* allocate some space for extra aux values */
 158                   "\tpushl %eax\n"            /* orig stack pointer */
 159                   "\tpushl %esp\n"            /* ptr to orig stack pointer */
 160                   "\tcall wld_start\n"
 161                   "\tpopl %ecx\n"             /* remove ptr to stack pointer */
 162                   "\tpopl %esp\n"             /* new stack pointer */
 163                   "\tpush %eax\n"             /* ELF interpreter entry point */
 164                   "\txor %eax,%eax\n"
 165                   "\txor %ecx,%ecx\n"
 166                   "\txor %edx,%edx\n"
 167                   "\tret\n")
 168
 169 /* wrappers for Linux system calls */
 170
 171 #define SYSCALL_RET(ret) (((ret) < 0 && (ret) > -4096) ? -1 : (ret))
 172
 173 static inline __attribute__((noreturn)) void wld_exit( int code )
 174 {
 175     for (;;)  /* avoid warning */
 176         __asm__ __volatile__( "int $0x80" : : "a" (SYS_exit), "b" (code) );
 177 }
 178
 179 static inline int wld_open( const char *name, int flags )
 180 {
 181     int ret;
 182     __asm__ __volatile__( "int $0x80" : "=a" (ret) : "0" (SYS_open), "b" (name), "c" (flags) );
 183     return SYSCALL_RET(ret);
 184 }
 185
 186 static inline int wld_close( int fd )
 187 {
 188     int ret;
 189     __asm__ __volatile__( "int $0x80" : "=a" (ret) : "0" (SYS_close), "b" (fd) );
 190     return SYSCALL_RET(ret);
 191 }
 192
 193 static inline ssize_t wld_read( int fd, void *buffer, size_t len )
 194 {
 195     int ret;
 196     __asm__ __volatile__( "int $0x80" : "=a" (ret)
 197                           : "0" (SYS_read), "b" (fd), "c" (buffer), "d" (len)
 198                           : "memory" );
 199     return SYSCALL_RET(ret);
 200 }
 201
 202 static inline ssize_t wld_write( int fd, const void *buffer, size_t len )
 203 {
 204     int ret;
 205     __asm__ __volatile__( "int $0x80" : "=a" (ret)
 206                           : "0" (SYS_write), "b" (fd), "c" (buffer), "d" (len) );
 207     return SYSCALL_RET(ret);
 208 }
 209
 210 static inline int wld_mprotect( const void *addr, size_t len, int prot )
 211 {
 212     int ret;
 213     __asm__ __volatile__( "int $0x80" : "=a" (ret) : "0" (SYS_mprotect), "b" (addr), "c" (len), "d" (prot) );
 214     return SYSCALL_RET(ret);
 215 }
 216
 217 static void *wld_mmap( void *start, size_t len, int prot, int flags, int fd, off_t offset )
 218 {
 219     int ret;
 220
 221     struct
 222     {
 223         void        *addr;
 224         unsigned int length;
 225         unsigned int prot;
 226         unsigned int flags;
 227         unsigned int fd;
 228         unsigned int offset;
 229     } args;
 230
 231     args.addr   = start;
 232     args.length = len;
 233     args.prot   = prot;
 234     args.flags  = flags;
 235     args.fd     = fd;
 236     args.offset = offset;
 237     __asm__ __volatile__( "int $0x80" : "=a" (ret) : "0" (SYS_mmap), "b" (&args) : "memory" );
 238     return (void *)SYSCALL_RET(ret);
 239 }
 240
 241 static inline uid_t wld_getuid(void)
 242 {
 243     uid_t ret;
 244     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getuid) );
 245     return ret;
 246 }
 247
 248 static inline uid_t wld_geteuid(void)
 249 {
 250     uid_t ret;
 251     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_geteuid) );
 252     return ret;
 253 }
 254
 255 static inline gid_t wld_getgid(void)
 256 {
 257     gid_t ret;
 258     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getgid) );
 259     return ret;
 260 }
 261
 262 static inline gid_t wld_getegid(void)
 263 {
 264     gid_t ret;
 265     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getegid) );
 266     return ret;
 267 }
 268
 269
 270 /* replacement for libc functions */
 271
 272 static int wld_strcmp( const char *str1, const char *str2 )
 273 {
 274     while (*str1 && (*str1 == *str2)) { str1++; str2++; }
 275     return *str1 - *str2;
 276 }
 277
 278 static int wld_strncmp( const char *str1, const char *str2, size_t len )
 279 {
 280     if (len <= 0) return 0;
 281     while ((--len > 0) && *str1 && (*str1 == *str2)) { str1++; str2++; }
 282     return *str1 - *str2;
 283 }
 284
 285 static inline void *wld_memset( void *dest, int val, size_t len )
 286 {
 287     char *dst = dest;
 288     while (len--) *dst++ = val;
 289     return dest;
 290 }
 291
 292 /*
 293  * wld_printf - just the basics
 294  *
 295  *  %x prints a hex number
 296  *  %s prints a string
 297  */
 298 static int wld_vsprintf(char *buffer, const char *fmt, va_list args )
 299 {
 300     static const char hex_chars[16] = "0123456789abcdef";
 301     const char *p = fmt;
 302     char *str = buffer;
 303
 304     while( *p )
 305     {
 306         if( *p == '%' )
 307         {
 308             p++;
 309             if( *p == 'x' )
 310             {
 311                 int i;
 312                 unsigned int x = va_arg( args, unsigned int );
 313                 for(i=7; i>=0; i--)
 314                     *str++ = hex_chars[(x>>(i*4))&0xf];
 315             }
 316             else if( *p == 's' )
 317             {
 318                 char *s = va_arg( args, char * );
 319                 while(*s)
 320                     *str++ = *s++;
 321             }
 322             else if( *p == 0 )
 323                 break;
 324             p++;
 325         }
 326         *str++ = *p++;
 327     }
 328     *str = 0;
 329     return str - buffer;
 330 }
 331
 332 static void wld_printf(const char *fmt, ... )
 333 {
 334     va_list args;
 335     char buffer[256];
 336     int len;
 337
 338     va_start( args, fmt );
 339     len = wld_vsprintf(buffer, fmt, args );
 340     va_end( args );
 341     wld_write(2, buffer, len);
 342 }
 343
 344 static __attribute__((noreturn)) void fatal_error(const char *fmt, ... )
 345 {
 346     va_list args;
 347     char buffer[256];
 348     int len;
 349
 350     va_start( args, fmt );
 351     len = wld_vsprintf(buffer, fmt, args );
 352     va_end( args );
 353     wld_write(2, buffer, len);
 354     wld_exit(1);
 355 }
 356
 357 #ifdef DUMP_AUX_INFO
 358 /*
 359  *  Dump interesting bits of the ELF auxv_t structure that is passed
 360  *   as the 4th parameter to the _start function
 361  */
 362 static void dump_auxiliary( ElfW(auxv_t) *av )
 363 {
 364 #define NAME(at) { at, #at }
 365     static const struct { int val; const char *name; } names[] =
 366     {
 367         NAME(AT_BASE),
 368         NAME(AT_CLKTCK),
 369         NAME(AT_EGID),
 370         NAME(AT_ENTRY),
 371         NAME(AT_EUID),
 372         NAME(AT_FLAGS),
 373         NAME(AT_GID),
 374         NAME(AT_HWCAP),
 375         NAME(AT_PAGESZ),
 376         NAME(AT_PHDR),
 377         NAME(AT_PHENT),
 378         NAME(AT_PHNUM),
 379         NAME(AT_PLATFORM),
 380         NAME(AT_SYSINFO),
 381         NAME(AT_SYSINFO_EHDR),
 382         NAME(AT_UID),
 383         { 0, NULL }
 384     };
 385 #undef NAME
 386
 387     int i;
 388
 389     for (  ; av->a_type != AT_NULL; av++)
 390     {
 391         for (i = 0; names[i].name; i++) if (names[i].val == av->a_type) break;
 392         if (names[i].name) wld_printf("%s = %x\n", names[i].name, av->a_un.a_val);
 393         else wld_printf( "%x = %x\n", av->a_type, av->a_un.a_val );
 394     }
 395 }
 396 #endif
 397
 398 /*
 399  * set_auxiliary_values
 400  *
 401  * Set the new auxiliary values
 402  */
 403 static void set_auxiliary_values( ElfW(auxv_t) *av, const ElfW(auxv_t) *new_av,
 404                                   const ElfW(auxv_t) *delete_av, void **stack )
 405 {
 406     int i, j, av_count = 0, new_count = 0, delete_count = 0;
 407     char *src, *dst;
 408
 409     /* count how many aux values we have already */
 410     while (av[av_count].a_type != AT_NULL) av_count++;
 411
 412     /* delete unwanted values */
 413     for (j = 0; delete_av[j].a_type != AT_NULL; j++)
 414     {
 415         for (i = 0; i < av_count; i++) if (av[i].a_type == delete_av[j].a_type)
 416         {
 417             av[i].a_type = av[av_count-1].a_type;
 418             av[i].a_un.a_val = av[av_count-1].a_un.a_val;
 419             av[--av_count].a_type = AT_NULL;
 420             delete_count++;
 421             break;
 422         }
 423     }
 424
 425     /* count how many values we have in new_av that aren't in av */
 426     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 427     {
 428         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 429         if (i == av_count) new_count++;
 430     }
 431
 432     src = (char *)*stack;
 433     dst = src - (new_count - delete_count) * sizeof(*av);
 434     if (new_count > delete_count)   /* need to make room for the extra values */
 435     {
 436         int len = (char *)(av + av_count + 1) - src;
 437         for (i = 0; i < len; i++) dst[i] = src[i];
 438     }
 439     else if (new_count < delete_count)  /* get rid of unused values */
 440     {
 441         int len = (char *)(av + av_count + 1) - dst;
 442         for (i = len - 1; i >= 0; i--) dst[i] = src[i];
 443     }
 444     *stack = dst;
 445     av -= (new_count - delete_count);
 446
 447     /* now set the values */
 448     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 449     {
 450         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 451         if (i < av_count) av[i].a_un.a_val = new_av[j].a_un.a_val;
 452         else
 453         {
 454             av[av_count].a_type     = new_av[j].a_type;
 455             av[av_count].a_un.a_val = new_av[j].a_un.a_val;
 456             av_count++;
 457         }
 458     }
 459
 460 #ifdef DUMP_AUX_INFO
 461     wld_printf("New auxiliary info:\n");
 462     dump_auxiliary( av );
 463 #endif
 464 }
 465
 466 /*
 467  * get_auxiliary
 468  *
 469  * Get a field of the auxiliary structure
 470  */
 471 static int get_auxiliary( ElfW(auxv_t) *av, int type, int def_val )
 472 {
 473   for ( ; av->a_type != AT_NULL; av++)
 474       if( av->a_type == type ) return av->a_un.a_val;
 475   return def_val;
 476 }
 477
 478 /*
 479  * map_so_lib
 480  *
 481  * modelled after _dl_map_object_from_fd() from glibc-2.3.1/elf/dl-load.c
 482  *
 483  * This function maps the segments from an ELF object, and optionally
 484  *  stores information about the mapping into the auxv_t structure.
 485  */
 486 static void map_so_lib( const char *name, struct wld_link_map *l)
 487 {
 488     int fd;
 489     unsigned char buf[0x800];
 490     ElfW(Ehdr) *header = (ElfW(Ehdr)*)buf;
 491     ElfW(Phdr) *phdr, *ph;
 492     /* Scan the program header table, collecting its load commands.  */
 493     struct loadcmd
 494       {
 495         ElfW(Addr) mapstart, mapend, dataend, allocend;
 496         off_t mapoff;
 497         int prot;
 498       } loadcmds[16], *c;
 499     size_t nloadcmds = 0, maplength;
 500
 501     fd = wld_open( name, O_RDONLY );
 502     if (fd == -1) fatal_error("%s: could not open\n", name );
 503
 504     if (wld_read( fd, buf, sizeof(buf) ) != sizeof(buf))
 505         fatal_error("%s: failed to read ELF header\n", name);
 506
 507     phdr = (void*) (((unsigned char*)buf) + header->e_phoff);
 508
 509     if( ( header->e_ident[0] != 0x7f ) ||
 510         ( header->e_ident[1] != 'E' ) ||
 511         ( header->e_ident[2] != 'L' ) ||
 512         ( header->e_ident[3] != 'F' ) )
 513         fatal_error( "%s: not an ELF binary... don't know how to load it\n", name );
 514
 515     if( header->e_machine != EM_386 )
 516         fatal_error("%s: not an i386 ELF binary... don't know how to load it\n", name );
 517
 518     if (header->e_phnum > sizeof(loadcmds)/sizeof(loadcmds[0]))
 519         fatal_error( "%s: oops... not enough space for load commands\n", name );
 520
 521     maplength = header->e_phnum * sizeof (ElfW(Phdr));
 522     if (header->e_phoff + maplength > sizeof(buf))
 523         fatal_error( "%s: oops... not enough space for ELF headers\n", name );
 524
 525     l->l_ld = 0;
 526     l->l_addr = 0;
 527     l->l_phdr = 0;
 528     l->l_phnum = header->e_phnum;
 529     l->l_entry = header->e_entry;
 530     l->l_interp = 0;
 531
 532     for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
 533     {
 534
 535 #ifdef DUMP_SEGMENTS
 536       wld_printf( "ph = %x\n", ph );
 537       wld_printf( " p_type   = %x\n", ph->p_type );
 538       wld_printf( " p_flags  = %x\n", ph->p_flags );
 539       wld_printf( " p_offset = %x\n", ph->p_offset );
 540       wld_printf( " p_vaddr  = %x\n", ph->p_vaddr );
 541       wld_printf( " p_paddr  = %x\n", ph->p_paddr );
 542       wld_printf( " p_filesz = %x\n", ph->p_filesz );
 543       wld_printf( " p_memsz  = %x\n", ph->p_memsz );
 544       wld_printf( " p_align  = %x\n", ph->p_align );
 545 #endif
 546
 547       switch (ph->p_type)
 548         {
 549           /* These entries tell us where to find things once the file's
 550              segments are mapped in.  We record the addresses it says
 551              verbatim, and later correct for the run-time load address.  */
 552         case PT_DYNAMIC:
 553           l->l_ld = (void *) ph->p_vaddr;
 554           l->l_ldnum = ph->p_memsz / sizeof (Elf32_Dyn);
 555           break;
 556
 557         case PT_PHDR:
 558           l->l_phdr = (void *) ph->p_vaddr;
 559           break;
 560
 561         case PT_LOAD:
 562           {
 563             if ((ph->p_align & page_mask) != 0)
 564               fatal_error( "%s: ELF load command alignment not page-aligned\n", name );
 565
 566             if (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)
 567               fatal_error( "%s: ELF load command address/offset not properly aligned\n", name );
 568
 569             c = &loadcmds[nloadcmds++];
 570             c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
 571             c->mapend = ((ph->p_vaddr + ph->p_filesz + page_mask) & ~page_mask);
 572             c->dataend = ph->p_vaddr + ph->p_filesz;
 573             c->allocend = ph->p_vaddr + ph->p_memsz;
 574             c->mapoff = ph->p_offset & ~(ph->p_align - 1);
 575
 576             c->prot = 0;
 577             if (ph->p_flags & PF_R)
 578               c->prot |= PROT_READ;
 579             if (ph->p_flags & PF_W)
 580               c->prot |= PROT_WRITE;
 581             if (ph->p_flags & PF_X)
 582               c->prot |= PROT_EXEC;
 583           }
 584           break;
 585
 586         case PT_INTERP:
 587           l->l_interp = ph->p_vaddr;
 588           break;
 589
 590         case PT_TLS:
 591           /*
 592            * We don't need to set anything up because we're
 593            * emulating the kernel, not ld-linux.so.2
 594            * The ELF loader will set up the TLS data itself.
 595            */
 596         case PT_SHLIB:
 597         case PT_NOTE:
 598         default:
 599           break;
 600         }
 601     }
 602
 603     /* Now process the load commands and map segments into memory.  */
 604     c = loadcmds;
 605
 606     /* Length of the sections to be loaded.  */
 607     maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
 608
 609     if( header->e_type == ET_DYN )
 610     {
 611         ElfW(Addr) mappref;
 612         mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
 613                    - MAP_BASE_ADDR (l));
 614
 615         /* Remember which part of the address space this object uses.  */
 616         l->l_map_start = (ElfW(Addr)) wld_mmap ((void *) mappref, maplength,
 617                                               c->prot, MAP_COPY | MAP_FILE,
 618                                               fd, c->mapoff);
 619         /* wld_printf("set  : offset = %x\n", c->mapoff); */
 620         /* wld_printf("l->l_map_start = %x\n", l->l_map_start); */
 621
 622         l->l_map_end = l->l_map_start + maplength;
 623         l->l_addr = l->l_map_start - c->mapstart;
 624
 625         wld_mprotect ((caddr_t) (l->l_addr + c->mapend),
 626                     loadcmds[nloadcmds - 1].allocend - c->mapend,
 627                     PROT_NONE);
 628         goto postmap;
 629     }
 630     else
 631     {
 632         /* sanity check */
 633         if ((char *)c->mapstart + maplength > preloader_start &&
 634             (char *)c->mapstart <= preloader_end)
 635             fatal_error( "%s: binary overlaps preloader (%x-%x)\n",
 636                          name, c->mapstart, (char *)c->mapstart + maplength );
 637
 638         ELF_FIXED_ADDRESS (loader, c->mapstart);
 639     }
 640
 641     /* Remember which part of the address space this object uses.  */
 642     l->l_map_start = c->mapstart + l->l_addr;
 643     l->l_map_end = l->l_map_start + maplength;
 644
 645     while (c < &loadcmds[nloadcmds])
 646       {
 647         if (c->mapend > c->mapstart)
 648             /* Map the segment contents from the file.  */
 649             wld_mmap ((void *) (l->l_addr + c->mapstart),
 650                         c->mapend - c->mapstart, c->prot,
 651                         MAP_FIXED | MAP_COPY | MAP_FILE, fd, c->mapoff);
 652
 653       postmap:
 654         if (l->l_phdr == 0
 655             && (ElfW(Off)) c->mapoff <= header->e_phoff
 656             && ((size_t) (c->mapend - c->mapstart + c->mapoff)
 657                 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
 658           /* Found the program header in this segment.  */
 659           l->l_phdr = (void *)(unsigned int) (c->mapstart + header->e_phoff - c->mapoff);
 660
 661         if (c->allocend > c->dataend)
 662           {
 663             /* Extra zero pages should appear at the end of this segment,
 664                after the data mapped from the file.   */
 665             ElfW(Addr) zero, zeroend, zeropage;
 666
 667             zero = l->l_addr + c->dataend;
 668             zeroend = l->l_addr + c->allocend;
 669             zeropage = (zero + page_mask) & ~page_mask;
 670
 671             /*
 672              * This is different from the dl-load load...
 673              *  ld-linux.so.2 relies on the whole page being zero'ed
 674              */
 675             zeroend = (zeroend + page_mask) & ~page_mask;
 676
 677             if (zeroend < zeropage)
 678             {
 679               /* All the extra data is in the last page of the segment.
 680                  We can just zero it.  */
 681               zeropage = zeroend;
 682             }
 683
 684             if (zeropage > zero)
 685               {
 686                 /* Zero the final part of the last page of the segment.  */
 687                 if ((c->prot & PROT_WRITE) == 0)
 688                   {
 689                     /* Dag nab it.  */
 690                     wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot|PROT_WRITE);
 691                   }
 692                 wld_memset ((void *) zero, '\0', zeropage - zero);
 693                 if ((c->prot & PROT_WRITE) == 0)
 694                   wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot);
 695               }
 696
 697             if (zeroend > zeropage)
 698               {
 699                 /* Map the remaining zero pages in from the zero fill FD.  */
 700                 caddr_t mapat;
 701                 mapat = wld_mmap ((caddr_t) zeropage, zeroend - zeropage,
 702                                 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
 703                                 -1, 0);
 704               }
 705           }
 706
 707         ++c;
 708       }
 709
 710     if (l->l_phdr == NULL) fatal_error("no program header\n");
 711
 712     l->l_phdr = (void *)((ElfW(Addr))l->l_phdr + l->l_addr);
 713     l->l_entry += l->l_addr;
 714
 715     wld_close( fd );
 716 }
 717
 718
 719 /*
 720  * Find a symbol in the symbol table of the executable loaded
 721  */
 722 static void *find_symbol( const ElfW(Phdr) *phdr, int num, char *var )
 723 {
 724     const ElfW(Dyn) *dyn = NULL;
 725     const ElfW(Phdr) *ph;
 726     const ElfW(Sym) *symtab = NULL;
 727     const char *strings = NULL;
 728     uint32_t i, symtabend = 0;
 729
 730     /* check the values */
 731 #ifdef DUMP_SYMS
 732     wld_printf("%x %x\n", phdr, num );
 733 #endif
 734     if( ( phdr == NULL ) || ( num == 0 ) )
 735     {
 736         wld_printf("could not find PT_DYNAMIC header entry\n");
 737         return NULL;
 738     }
 739
 740     /* parse the (already loaded) ELF executable's header */
 741     for (ph = phdr; ph < &phdr[num]; ++ph)
 742     {
 743         if( PT_DYNAMIC == ph->p_type )
 744         {
 745             dyn = (void *) ph->p_vaddr;
 746             num = ph->p_memsz / sizeof (Elf32_Dyn);
 747             break;
 748         }
 749     }
 750     if( !dyn ) return NULL;
 751
 752     while( dyn->d_tag )
 753     {
 754         if( dyn->d_tag == DT_STRTAB )
 755             strings = (const char*) dyn->d_un.d_ptr;
 756         if( dyn->d_tag == DT_SYMTAB )
 757             symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
 758         if( dyn->d_tag == DT_HASH )
 759             symtabend = *((const uint32_t *)dyn->d_un.d_ptr + 1);
 760 #ifdef DUMP_SYMS
 761         wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
 762 #endif
 763         dyn++;
 764     }
 765
 766     if( (!symtab) || (!strings) ) return NULL;
 767
 768     for (i = 0; i < symtabend; i++)
 769     {
 770         if( ( ELF32_ST_BIND(symtab[i].st_info) == STT_OBJECT ) &&
 771             ( 0 == wld_strcmp( strings+symtab[i].st_name, var ) ) )
 772         {
 773 #ifdef DUMP_SYMS
 774             wld_printf("Found %s -> %x\n", strings+symtab[i].st_name, symtab[i].st_value );
 775 #endif
 776             return (void*)symtab[i].st_value;
 777         }
 778     }
 779     return NULL;
 780 }
 781
 782 /*
 783  *  preload_reserve
 784  *
 785  * Reserve a range specified in string format
 786  */
 787 static void preload_reserve( const char *str )
 788 {
 789     const char *p;
 790     unsigned long result = 0;
 791     void *start = NULL, *end = NULL;
 792     int first = 1;
 793
 794     for (p = str; *p; p++)
 795     {
 796         if (*p >= '0' && *p <= '9') result = result * 16 + *p - '0';
 797         else if (*p >= 'a' && *p <= 'f') result = result * 16 + *p - 'a' + 10;
 798         else if (*p >= 'A' && *p <= 'F') result = result * 16 + *p - 'A' + 10;
 799         else if (*p == '-')
 800         {
 801             if (!first) goto error;
 802             start = (void *)(result & ~page_mask);
 803             result = 0;
 804             first = 0;
 805         }
 806         else goto error;
 807     }
 808     if (!first) end = (void *)((result + page_mask) & ~page_mask);
 809     else if (result) goto error;  /* single value '0' is allowed */
 810
 811     /* sanity checks */
 812     if (end <= start) start = end = NULL;
 813     else if ((char *)end > preloader_start &&
 814              (char *)start <= preloader_end)
 815     {
 816         wld_printf( "WINEPRELOADRESERVE range %x-%x overlaps preloader %x-%x\n",
 817                      start, end, preloader_start, preloader_end );
 818         start = end = NULL;
 819     }
 820
 821     /* entry 2 is for the PE exe */
 822     preload_info[2].addr = start;
 823     preload_info[2].size = (char *)end - (char *)start;
 824     return;
 825
 826 error:
 827     fatal_error( "invalid WINEPRELOADRESERVE value '%s'\n", str );
 828 }
 829
 830 /*
 831  *  is_in_preload_range
 832  *
 833  * Check if address of the given aux value is in one of the reserved ranges
 834  */
 835 static int is_in_preload_range( const ElfW(auxv_t) *av, int type )
 836 {
 837     int i;
 838
 839     while (av->a_type != type && av->a_type != AT_NULL) av++;
 840
 841     if (av->a_type == type)
 842     {
 843         for (i = 0; preload_info[i].size; i++)
 844         {
 845             if ((char *)av->a_un.a_ptr >= (char *)preload_info[i].addr &&
 846                 (char *)av->a_un.a_ptr < (char *)preload_info[i].addr + preload_info[i].size)
 847                 return 1;
 848         }
 849     }
 850     return 0;
 851 }
 852
 853 /*
 854  *  wld_start
 855  *
 856  *  Repeat the actions the kernel would do when loading a dynamically linked .so
 857  *  Load the binary and then its ELF interpreter.
 858  *  Note, we assume that the binary is a dynamically linked ELF shared object.
 859  */
 860 void* wld_start( void **stack )
 861 {
 862     int i, *pargc;
 863     char **argv, **p;
 864     char *interp, *reserve = NULL;
 865     ElfW(auxv_t) new_av[12], delete_av[3], *av;
 866     struct wld_link_map main_binary_map, ld_so_map;
 867     struct wine_preload_info **wine_main_preload_info;
 868
 869     pargc = *stack;
 870     argv = (char **)pargc + 1;
 871     if (*pargc < 2) fatal_error( "Usage: %s wine_binary [args]\n", argv[0] );
 872
 873     /* skip over the parameters */
 874     p = argv + *pargc + 1;
 875
 876     /* skip over the environment */
 877     while (*p)
 878     {
 879         static const char res[] = "WINEPRELOADRESERVE=";
 880         if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p + sizeof(res) - 1;
 881         p++;
 882     }
 883
 884     av = (ElfW(auxv_t)*) (p+1);
 885     page_size = get_auxiliary( av, AT_PAGESZ, 4096 );
 886     page_mask = page_size - 1;
 887
 888     preloader_start = (char *)_start - ((unsigned int)_start & page_mask);
 889     preloader_end = (char *)((unsigned int)(_end + page_mask) & ~page_mask);
 890
 891 #ifdef DUMP_AUX_INFO
 892     wld_printf( "stack = %x\n", *stack );
 893     for( i = 0; i < *pargc; i++ ) wld_printf("argv[%x] = %s\n", i, argv[i]);
 894     dump_auxiliary( av );
 895 #endif
 896
 897     /* reserve memory that Wine needs */
 898     if (reserve) preload_reserve( reserve );
 899     for (i = 0; preload_info[i].size; i++)
 900         wld_mmap( preload_info[i].addr, preload_info[i].size,
 901                   PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0 );
 902
 903     /* load the main binary */
 904     map_so_lib( argv[1], &main_binary_map );
 905
 906     /* load the ELF interpreter */
 907     interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
 908     map_so_lib( interp, &ld_so_map );
 909
 910     /* store pointer to the preload info into the appropriate main binary variable */
 911     wine_main_preload_info = find_symbol( main_binary_map.l_phdr, main_binary_map.l_phnum,
 912                                           "wine_main_preload_info" );
 913     if (wine_main_preload_info) *wine_main_preload_info = preload_info;
 914     else wld_printf( "wine_main_preload_info not found\n" );
 915
 916 #define SET_NEW_AV(n,type,val) new_av[n].a_type = (type); new_av[n].a_un.a_val = (val);
 917     SET_NEW_AV( 0, AT_PHDR, (unsigned long)main_binary_map.l_phdr );
 918     SET_NEW_AV( 1, AT_PHENT, sizeof(ElfW(Phdr)) );
 919     SET_NEW_AV( 2, AT_PHNUM, main_binary_map.l_phnum );
 920     SET_NEW_AV( 3, AT_PAGESZ, page_size );
 921     SET_NEW_AV( 4, AT_BASE, ld_so_map.l_addr );
 922     SET_NEW_AV( 5, AT_FLAGS, get_auxiliary( av, AT_FLAGS, 0 ) );
 923     SET_NEW_AV( 6, AT_ENTRY, main_binary_map.l_entry );
 924     SET_NEW_AV( 7, AT_UID, get_auxiliary( av, AT_UID, wld_getuid() ) );
 925     SET_NEW_AV( 8, AT_EUID, get_auxiliary( av, AT_EUID, wld_geteuid() ) );
 926     SET_NEW_AV( 9, AT_GID, get_auxiliary( av, AT_GID, wld_getgid() ) );
 927     SET_NEW_AV(10, AT_EGID, get_auxiliary( av, AT_EGID, wld_getegid() ) );
 928     SET_NEW_AV(11, AT_NULL, 0 );
 929 #undef SET_NEW_AV
 930
 931     i = 0;
 932     /* delete sysinfo values if addresses conflict */
 933     if (is_in_preload_range( av, AT_SYSINFO )) delete_av[i++].a_type = AT_SYSINFO;
 934     if (is_in_preload_range( av, AT_SYSINFO_EHDR )) delete_av[i++].a_type = AT_SYSINFO_EHDR;
 935     delete_av[i].a_type = AT_NULL;
 936
 937     /* get rid of first argument */
 938     pargc[1] = pargc[0] - 1;
 939     *stack = pargc + 1;
 940
 941     set_auxiliary_values( av, new_av, delete_av, stack );
 942
 943 #ifdef DUMP_AUX_INFO
 944     wld_printf("new stack = %x\n", *stack);
 945     wld_printf("jumping to %x\n", ld_so_map.l_entry);
 946 #endif
 947
 948     return (void *)ld_so_map.l_entry;
 949 }