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__( "pushl %%ebx; movl %1,%%ebx; int $0x80; popl %%ebx"
 177                               : : "a" (SYS_exit), "r" (code) );
 178 }
 179
 180 static inline int wld_open( const char *name, int flags )
 181 {
 182     int ret;
 183     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 184                           : "=a" (ret) : "0" (SYS_open), "r" (name), "c" (flags) );
 185     return SYSCALL_RET(ret);
 186 }
 187
 188 static inline int wld_close( int fd )
 189 {
 190     int ret;
 191     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 192                           : "=a" (ret) : "0" (SYS_close), "r" (fd) );
 193     return SYSCALL_RET(ret);
 194 }
 195
 196 static inline ssize_t wld_read( int fd, void *buffer, size_t len )
 197 {
 198     int ret;
 199     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 200                           : "=a" (ret)
 201                           : "0" (SYS_read), "r" (fd), "c" (buffer), "d" (len)
 202                           : "memory" );
 203     return SYSCALL_RET(ret);
 204 }
 205
 206 static inline ssize_t wld_write( int fd, const void *buffer, size_t len )
 207 {
 208     int ret;
 209     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 210                           : "=a" (ret) : "0" (SYS_write), "r" (fd), "c" (buffer), "d" (len) );
 211     return SYSCALL_RET(ret);
 212 }
 213
 214 static inline int wld_mprotect( const void *addr, size_t len, int prot )
 215 {
 216     int ret;
 217     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 218                           : "=a" (ret) : "0" (SYS_mprotect), "r" (addr), "c" (len), "d" (prot) );
 219     return SYSCALL_RET(ret);
 220 }
 221
 222 static void *wld_mmap( void *start, size_t len, int prot, int flags, int fd, off_t offset )
 223 {
 224     int ret;
 225
 226     struct
 227     {
 228         void        *addr;
 229         unsigned int length;
 230         unsigned int prot;
 231         unsigned int flags;
 232         unsigned int fd;
 233         unsigned int offset;
 234     } args;
 235
 236     args.addr   = start;
 237     args.length = len;
 238     args.prot   = prot;
 239     args.flags  = flags;
 240     args.fd     = fd;
 241     args.offset = offset;
 242     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 243                           : "=a" (ret) : "0" (SYS_mmap), "q" (&args) : "memory" );
 244     return (void *)SYSCALL_RET(ret);
 245 }
 246
 247 static inline uid_t wld_getuid(void)
 248 {
 249     uid_t ret;
 250     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getuid) );
 251     return ret;
 252 }
 253
 254 static inline uid_t wld_geteuid(void)
 255 {
 256     uid_t ret;
 257     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_geteuid) );
 258     return ret;
 259 }
 260
 261 static inline gid_t wld_getgid(void)
 262 {
 263     gid_t ret;
 264     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getgid) );
 265     return ret;
 266 }
 267
 268 static inline gid_t wld_getegid(void)
 269 {
 270     gid_t ret;
 271     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getegid) );
 272     return ret;
 273 }
 274
 275
 276 /* replacement for libc functions */
 277
 278 static int wld_strcmp( const char *str1, const char *str2 )
 279 {
 280     while (*str1 && (*str1 == *str2)) { str1++; str2++; }
 281     return *str1 - *str2;
 282 }
 283
 284 static int wld_strncmp( const char *str1, const char *str2, size_t len )
 285 {
 286     if (len <= 0) return 0;
 287     while ((--len > 0) && *str1 && (*str1 == *str2)) { str1++; str2++; }
 288     return *str1 - *str2;
 289 }
 290
 291 static inline void *wld_memset( void *dest, int val, size_t len )
 292 {
 293     char *dst = dest;
 294     while (len--) *dst++ = val;
 295     return dest;
 296 }
 297
 298 /*
 299  * wld_printf - just the basics
 300  *
 301  *  %x prints a hex number
 302  *  %s prints a string
 303  */
 304 static int wld_vsprintf(char *buffer, const char *fmt, va_list args )
 305 {
 306     static const char hex_chars[16] = "0123456789abcdef";
 307     const char *p = fmt;
 308     char *str = buffer;
 309
 310     while( *p )
 311     {
 312         if( *p == '%' )
 313         {
 314             p++;
 315             if( *p == 'x' )
 316             {
 317                 int i;
 318                 unsigned int x = va_arg( args, unsigned int );
 319                 for(i=7; i>=0; i--)
 320                     *str++ = hex_chars[(x>>(i*4))&0xf];
 321             }
 322             else if( *p == 's' )
 323             {
 324                 char *s = va_arg( args, char * );
 325                 while(*s)
 326                     *str++ = *s++;
 327             }
 328             else if( *p == 0 )
 329                 break;
 330             p++;
 331         }
 332         *str++ = *p++;
 333     }
 334     *str = 0;
 335     return str - buffer;
 336 }
 337
 338 static void wld_printf(const char *fmt, ... )
 339 {
 340     va_list args;
 341     char buffer[256];
 342     int len;
 343
 344     va_start( args, fmt );
 345     len = wld_vsprintf(buffer, fmt, args );
 346     va_end( args );
 347     wld_write(2, buffer, len);
 348 }
 349
 350 static __attribute__((noreturn)) void fatal_error(const char *fmt, ... )
 351 {
 352     va_list args;
 353     char buffer[256];
 354     int len;
 355
 356     va_start( args, fmt );
 357     len = wld_vsprintf(buffer, fmt, args );
 358     va_end( args );
 359     wld_write(2, buffer, len);
 360     wld_exit(1);
 361 }
 362
 363 #ifdef DUMP_AUX_INFO
 364 /*
 365  *  Dump interesting bits of the ELF auxv_t structure that is passed
 366  *   as the 4th parameter to the _start function
 367  */
 368 static void dump_auxiliary( ElfW(auxv_t) *av )
 369 {
 370 #define NAME(at) { at, #at }
 371     static const struct { int val; const char *name; } names[] =
 372     {
 373         NAME(AT_BASE),
 374         NAME(AT_CLKTCK),
 375         NAME(AT_EGID),
 376         NAME(AT_ENTRY),
 377         NAME(AT_EUID),
 378         NAME(AT_FLAGS),
 379         NAME(AT_GID),
 380         NAME(AT_HWCAP),
 381         NAME(AT_PAGESZ),
 382         NAME(AT_PHDR),
 383         NAME(AT_PHENT),
 384         NAME(AT_PHNUM),
 385         NAME(AT_PLATFORM),
 386         NAME(AT_SYSINFO),
 387         NAME(AT_SYSINFO_EHDR),
 388         NAME(AT_UID),
 389         { 0, NULL }
 390     };
 391 #undef NAME
 392
 393     int i;
 394
 395     for (  ; av->a_type != AT_NULL; av++)
 396     {
 397         for (i = 0; names[i].name; i++) if (names[i].val == av->a_type) break;
 398         if (names[i].name) wld_printf("%s = %x\n", names[i].name, av->a_un.a_val);
 399         else wld_printf( "%x = %x\n", av->a_type, av->a_un.a_val );
 400     }
 401 }
 402 #endif
 403
 404 /*
 405  * set_auxiliary_values
 406  *
 407  * Set the new auxiliary values
 408  */
 409 static void set_auxiliary_values( ElfW(auxv_t) *av, const ElfW(auxv_t) *new_av,
 410                                   const ElfW(auxv_t) *delete_av, void **stack )
 411 {
 412     int i, j, av_count = 0, new_count = 0, delete_count = 0;
 413     char *src, *dst;
 414
 415     /* count how many aux values we have already */
 416     while (av[av_count].a_type != AT_NULL) av_count++;
 417
 418     /* delete unwanted values */
 419     for (j = 0; delete_av[j].a_type != AT_NULL; j++)
 420     {
 421         for (i = 0; i < av_count; i++) if (av[i].a_type == delete_av[j].a_type)
 422         {
 423             av[i].a_type = av[av_count-1].a_type;
 424             av[i].a_un.a_val = av[av_count-1].a_un.a_val;
 425             av[--av_count].a_type = AT_NULL;
 426             delete_count++;
 427             break;
 428         }
 429     }
 430
 431     /* count how many values we have in new_av that aren't in av */
 432     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 433     {
 434         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 435         if (i == av_count) new_count++;
 436     }
 437
 438     src = (char *)*stack;
 439     dst = src - (new_count - delete_count) * sizeof(*av);
 440     if (new_count > delete_count)   /* need to make room for the extra values */
 441     {
 442         int len = (char *)(av + av_count + 1) - src;
 443         for (i = 0; i < len; i++) dst[i] = src[i];
 444     }
 445     else if (new_count < delete_count)  /* get rid of unused values */
 446     {
 447         int len = (char *)(av + av_count + 1) - dst;
 448         for (i = len - 1; i >= 0; i--) dst[i] = src[i];
 449     }
 450     *stack = dst;
 451     av -= (new_count - delete_count);
 452
 453     /* now set the values */
 454     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 455     {
 456         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 457         if (i < av_count) av[i].a_un.a_val = new_av[j].a_un.a_val;
 458         else
 459         {
 460             av[av_count].a_type     = new_av[j].a_type;
 461             av[av_count].a_un.a_val = new_av[j].a_un.a_val;
 462             av_count++;
 463         }
 464     }
 465
 466 #ifdef DUMP_AUX_INFO
 467     wld_printf("New auxiliary info:\n");
 468     dump_auxiliary( av );
 469 #endif
 470 }
 471
 472 /*
 473  * get_auxiliary
 474  *
 475  * Get a field of the auxiliary structure
 476  */
 477 static int get_auxiliary( ElfW(auxv_t) *av, int type, int def_val )
 478 {
 479   for ( ; av->a_type != AT_NULL; av++)
 480       if( av->a_type == type ) return av->a_un.a_val;
 481   return def_val;
 482 }
 483
 484 /*
 485  * map_so_lib
 486  *
 487  * modelled after _dl_map_object_from_fd() from glibc-2.3.1/elf/dl-load.c
 488  *
 489  * This function maps the segments from an ELF object, and optionally
 490  *  stores information about the mapping into the auxv_t structure.
 491  */
 492 static void map_so_lib( const char *name, struct wld_link_map *l)
 493 {
 494     int fd;
 495     unsigned char buf[0x800];
 496     ElfW(Ehdr) *header = (ElfW(Ehdr)*)buf;
 497     ElfW(Phdr) *phdr, *ph;
 498     /* Scan the program header table, collecting its load commands.  */
 499     struct loadcmd
 500       {
 501         ElfW(Addr) mapstart, mapend, dataend, allocend;
 502         off_t mapoff;
 503         int prot;
 504       } loadcmds[16], *c;
 505     size_t nloadcmds = 0, maplength;
 506
 507     fd = wld_open( name, O_RDONLY );
 508     if (fd == -1) fatal_error("%s: could not open\n", name );
 509
 510     if (wld_read( fd, buf, sizeof(buf) ) != sizeof(buf))
 511         fatal_error("%s: failed to read ELF header\n", name);
 512
 513     phdr = (void*) (((unsigned char*)buf) + header->e_phoff);
 514
 515     if( ( header->e_ident[0] != 0x7f ) ||
 516         ( header->e_ident[1] != 'E' ) ||
 517         ( header->e_ident[2] != 'L' ) ||
 518         ( header->e_ident[3] != 'F' ) )
 519         fatal_error( "%s: not an ELF binary... don't know how to load it\n", name );
 520
 521     if( header->e_machine != EM_386 )
 522         fatal_error("%s: not an i386 ELF binary... don't know how to load it\n", name );
 523
 524     if (header->e_phnum > sizeof(loadcmds)/sizeof(loadcmds[0]))
 525         fatal_error( "%s: oops... not enough space for load commands\n", name );
 526
 527     maplength = header->e_phnum * sizeof (ElfW(Phdr));
 528     if (header->e_phoff + maplength > sizeof(buf))
 529         fatal_error( "%s: oops... not enough space for ELF headers\n", name );
 530
 531     l->l_ld = 0;
 532     l->l_addr = 0;
 533     l->l_phdr = 0;
 534     l->l_phnum = header->e_phnum;
 535     l->l_entry = header->e_entry;
 536     l->l_interp = 0;
 537
 538     for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
 539     {
 540
 541 #ifdef DUMP_SEGMENTS
 542       wld_printf( "ph = %x\n", ph );
 543       wld_printf( " p_type   = %x\n", ph->p_type );
 544       wld_printf( " p_flags  = %x\n", ph->p_flags );
 545       wld_printf( " p_offset = %x\n", ph->p_offset );
 546       wld_printf( " p_vaddr  = %x\n", ph->p_vaddr );
 547       wld_printf( " p_paddr  = %x\n", ph->p_paddr );
 548       wld_printf( " p_filesz = %x\n", ph->p_filesz );
 549       wld_printf( " p_memsz  = %x\n", ph->p_memsz );
 550       wld_printf( " p_align  = %x\n", ph->p_align );
 551 #endif
 552
 553       switch (ph->p_type)
 554         {
 555           /* These entries tell us where to find things once the file's
 556              segments are mapped in.  We record the addresses it says
 557              verbatim, and later correct for the run-time load address.  */
 558         case PT_DYNAMIC:
 559           l->l_ld = (void *) ph->p_vaddr;
 560           l->l_ldnum = ph->p_memsz / sizeof (Elf32_Dyn);
 561           break;
 562
 563         case PT_PHDR:
 564           l->l_phdr = (void *) ph->p_vaddr;
 565           break;
 566
 567         case PT_LOAD:
 568           {
 569             if ((ph->p_align & page_mask) != 0)
 570               fatal_error( "%s: ELF load command alignment not page-aligned\n", name );
 571
 572             if (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)
 573               fatal_error( "%s: ELF load command address/offset not properly aligned\n", name );
 574
 575             c = &loadcmds[nloadcmds++];
 576             c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
 577             c->mapend = ((ph->p_vaddr + ph->p_filesz + page_mask) & ~page_mask);
 578             c->dataend = ph->p_vaddr + ph->p_filesz;
 579             c->allocend = ph->p_vaddr + ph->p_memsz;
 580             c->mapoff = ph->p_offset & ~(ph->p_align - 1);
 581
 582             c->prot = 0;
 583             if (ph->p_flags & PF_R)
 584               c->prot |= PROT_READ;
 585             if (ph->p_flags & PF_W)
 586               c->prot |= PROT_WRITE;
 587             if (ph->p_flags & PF_X)
 588               c->prot |= PROT_EXEC;
 589           }
 590           break;
 591
 592         case PT_INTERP:
 593           l->l_interp = ph->p_vaddr;
 594           break;
 595
 596         case PT_TLS:
 597           /*
 598            * We don't need to set anything up because we're
 599            * emulating the kernel, not ld-linux.so.2
 600            * The ELF loader will set up the TLS data itself.
 601            */
 602         case PT_SHLIB:
 603         case PT_NOTE:
 604         default:
 605           break;
 606         }
 607     }
 608
 609     /* Now process the load commands and map segments into memory.  */
 610     c = loadcmds;
 611
 612     /* Length of the sections to be loaded.  */
 613     maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
 614
 615     if( header->e_type == ET_DYN )
 616     {
 617         ElfW(Addr) mappref;
 618         mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
 619                    - MAP_BASE_ADDR (l));
 620
 621         /* Remember which part of the address space this object uses.  */
 622         l->l_map_start = (ElfW(Addr)) wld_mmap ((void *) mappref, maplength,
 623                                               c->prot, MAP_COPY | MAP_FILE,
 624                                               fd, c->mapoff);
 625         /* wld_printf("set  : offset = %x\n", c->mapoff); */
 626         /* wld_printf("l->l_map_start = %x\n", l->l_map_start); */
 627
 628         l->l_map_end = l->l_map_start + maplength;
 629         l->l_addr = l->l_map_start - c->mapstart;
 630
 631         wld_mprotect ((caddr_t) (l->l_addr + c->mapend),
 632                     loadcmds[nloadcmds - 1].allocend - c->mapend,
 633                     PROT_NONE);
 634         goto postmap;
 635     }
 636     else
 637     {
 638         /* sanity check */
 639         if ((char *)c->mapstart + maplength > preloader_start &&
 640             (char *)c->mapstart <= preloader_end)
 641             fatal_error( "%s: binary overlaps preloader (%x-%x)\n",
 642                          name, c->mapstart, (char *)c->mapstart + maplength );
 643
 644         ELF_FIXED_ADDRESS (loader, c->mapstart);
 645     }
 646
 647     /* Remember which part of the address space this object uses.  */
 648     l->l_map_start = c->mapstart + l->l_addr;
 649     l->l_map_end = l->l_map_start + maplength;
 650
 651     while (c < &loadcmds[nloadcmds])
 652       {
 653         if (c->mapend > c->mapstart)
 654             /* Map the segment contents from the file.  */
 655             wld_mmap ((void *) (l->l_addr + c->mapstart),
 656                         c->mapend - c->mapstart, c->prot,
 657                         MAP_FIXED | MAP_COPY | MAP_FILE, fd, c->mapoff);
 658
 659       postmap:
 660         if (l->l_phdr == 0
 661             && (ElfW(Off)) c->mapoff <= header->e_phoff
 662             && ((size_t) (c->mapend - c->mapstart + c->mapoff)
 663                 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
 664           /* Found the program header in this segment.  */
 665           l->l_phdr = (void *)(unsigned int) (c->mapstart + header->e_phoff - c->mapoff);
 666
 667         if (c->allocend > c->dataend)
 668           {
 669             /* Extra zero pages should appear at the end of this segment,
 670                after the data mapped from the file.   */
 671             ElfW(Addr) zero, zeroend, zeropage;
 672
 673             zero = l->l_addr + c->dataend;
 674             zeroend = l->l_addr + c->allocend;
 675             zeropage = (zero + page_mask) & ~page_mask;
 676
 677             /*
 678              * This is different from the dl-load load...
 679              *  ld-linux.so.2 relies on the whole page being zero'ed
 680              */
 681             zeroend = (zeroend + page_mask) & ~page_mask;
 682
 683             if (zeroend < zeropage)
 684             {
 685               /* All the extra data is in the last page of the segment.
 686                  We can just zero it.  */
 687               zeropage = zeroend;
 688             }
 689
 690             if (zeropage > zero)
 691               {
 692                 /* Zero the final part of the last page of the segment.  */
 693                 if ((c->prot & PROT_WRITE) == 0)
 694                   {
 695                     /* Dag nab it.  */
 696                     wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot|PROT_WRITE);
 697                   }
 698                 wld_memset ((void *) zero, '\0', zeropage - zero);
 699                 if ((c->prot & PROT_WRITE) == 0)
 700                   wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot);
 701               }
 702
 703             if (zeroend > zeropage)
 704               {
 705                 /* Map the remaining zero pages in from the zero fill FD.  */
 706                 caddr_t mapat;
 707                 mapat = wld_mmap ((caddr_t) zeropage, zeroend - zeropage,
 708                                 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
 709                                 -1, 0);
 710               }
 711           }
 712
 713         ++c;
 714       }
 715
 716     if (l->l_phdr == NULL) fatal_error("no program header\n");
 717
 718     l->l_phdr = (void *)((ElfW(Addr))l->l_phdr + l->l_addr);
 719     l->l_entry += l->l_addr;
 720
 721     wld_close( fd );
 722 }
 723
 724
 725 /*
 726  * Find a symbol in the symbol table of the executable loaded
 727  */
 728 static void *find_symbol( const ElfW(Phdr) *phdr, int num, char *var )
 729 {
 730     const ElfW(Dyn) *dyn = NULL;
 731     const ElfW(Phdr) *ph;
 732     const ElfW(Sym) *symtab = NULL;
 733     const char *strings = NULL;
 734     uint32_t i, symtabend = 0;
 735
 736     /* check the values */
 737 #ifdef DUMP_SYMS
 738     wld_printf("%x %x\n", phdr, num );
 739 #endif
 740     if( ( phdr == NULL ) || ( num == 0 ) )
 741     {
 742         wld_printf("could not find PT_DYNAMIC header entry\n");
 743         return NULL;
 744     }
 745
 746     /* parse the (already loaded) ELF executable's header */
 747     for (ph = phdr; ph < &phdr[num]; ++ph)
 748     {
 749         if( PT_DYNAMIC == ph->p_type )
 750         {
 751             dyn = (void *) ph->p_vaddr;
 752             num = ph->p_memsz / sizeof (Elf32_Dyn);
 753             break;
 754         }
 755     }
 756     if( !dyn ) return NULL;
 757
 758     while( dyn->d_tag )
 759     {
 760         if( dyn->d_tag == DT_STRTAB )
 761             strings = (const char*) dyn->d_un.d_ptr;
 762         if( dyn->d_tag == DT_SYMTAB )
 763             symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
 764         if( dyn->d_tag == DT_HASH )
 765             symtabend = *((const uint32_t *)dyn->d_un.d_ptr + 1);
 766 #ifdef DUMP_SYMS
 767         wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
 768 #endif
 769         dyn++;
 770     }
 771
 772     if( (!symtab) || (!strings) ) return NULL;
 773
 774     for (i = 0; i < symtabend; i++)
 775     {
 776         if( ( ELF32_ST_BIND(symtab[i].st_info) == STT_OBJECT ) &&
 777             ( 0 == wld_strcmp( strings+symtab[i].st_name, var ) ) )
 778         {
 779 #ifdef DUMP_SYMS
 780             wld_printf("Found %s -> %x\n", strings+symtab[i].st_name, symtab[i].st_value );
 781 #endif
 782             return (void*)symtab[i].st_value;
 783         }
 784     }
 785     return NULL;
 786 }
 787
 788 /*
 789  *  preload_reserve
 790  *
 791  * Reserve a range specified in string format
 792  */
 793 static void preload_reserve( const char *str )
 794 {
 795     const char *p;
 796     unsigned long result = 0;
 797     void *start = NULL, *end = NULL;
 798     int first = 1;
 799
 800     for (p = str; *p; p++)
 801     {
 802         if (*p >= '0' && *p <= '9') result = result * 16 + *p - '0';
 803         else if (*p >= 'a' && *p <= 'f') result = result * 16 + *p - 'a' + 10;
 804         else if (*p >= 'A' && *p <= 'F') result = result * 16 + *p - 'A' + 10;
 805         else if (*p == '-')
 806         {
 807             if (!first) goto error;
 808             start = (void *)(result & ~page_mask);
 809             result = 0;
 810             first = 0;
 811         }
 812         else goto error;
 813     }
 814     if (!first) end = (void *)((result + page_mask) & ~page_mask);
 815     else if (result) goto error;  /* single value '0' is allowed */
 816
 817     /* sanity checks */
 818     if (end <= start) start = end = NULL;
 819     else if ((char *)end > preloader_start &&
 820              (char *)start <= preloader_end)
 821     {
 822         wld_printf( "WINEPRELOADRESERVE range %x-%x overlaps preloader %x-%x\n",
 823                      start, end, preloader_start, preloader_end );
 824         start = end = NULL;
 825     }
 826
 827     /* entry 2 is for the PE exe */
 828     preload_info[2].addr = start;
 829     preload_info[2].size = (char *)end - (char *)start;
 830     return;
 831
 832 error:
 833     fatal_error( "invalid WINEPRELOADRESERVE value '%s'\n", str );
 834 }
 835
 836 /*
 837  *  is_in_preload_range
 838  *
 839  * Check if address of the given aux value is in one of the reserved ranges
 840  */
 841 static int is_in_preload_range( const ElfW(auxv_t) *av, int type )
 842 {
 843     int i;
 844
 845     while (av->a_type != type && av->a_type != AT_NULL) av++;
 846
 847     if (av->a_type == type)
 848     {
 849         for (i = 0; preload_info[i].size; i++)
 850         {
 851             if ((char *)av->a_un.a_ptr >= (char *)preload_info[i].addr &&
 852                 (char *)av->a_un.a_ptr < (char *)preload_info[i].addr + preload_info[i].size)
 853                 return 1;
 854         }
 855     }
 856     return 0;
 857 }
 858
 859 /*
 860  *  wld_start
 861  *
 862  *  Repeat the actions the kernel would do when loading a dynamically linked .so
 863  *  Load the binary and then its ELF interpreter.
 864  *  Note, we assume that the binary is a dynamically linked ELF shared object.
 865  */
 866 void* wld_start( void **stack )
 867 {
 868     int i, *pargc;
 869     char **argv, **p;
 870     char *interp, *reserve = NULL;
 871     ElfW(auxv_t) new_av[12], delete_av[3], *av;
 872     struct wld_link_map main_binary_map, ld_so_map;
 873     struct wine_preload_info **wine_main_preload_info;
 874
 875     pargc = *stack;
 876     argv = (char **)pargc + 1;
 877     if (*pargc < 2) fatal_error( "Usage: %s wine_binary [args]\n", argv[0] );
 878
 879     /* skip over the parameters */
 880     p = argv + *pargc + 1;
 881
 882     /* skip over the environment */
 883     while (*p)
 884     {
 885         static const char res[] = "WINEPRELOADRESERVE=";
 886         if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p + sizeof(res) - 1;
 887         p++;
 888     }
 889
 890     av = (ElfW(auxv_t)*) (p+1);
 891     page_size = get_auxiliary( av, AT_PAGESZ, 4096 );
 892     page_mask = page_size - 1;
 893
 894     preloader_start = (char *)_start - ((unsigned int)_start & page_mask);
 895     preloader_end = (char *)((unsigned int)(_end + page_mask) & ~page_mask);
 896
 897 #ifdef DUMP_AUX_INFO
 898     wld_printf( "stack = %x\n", *stack );
 899     for( i = 0; i < *pargc; i++ ) wld_printf("argv[%x] = %s\n", i, argv[i]);
 900     dump_auxiliary( av );
 901 #endif
 902
 903     /* reserve memory that Wine needs */
 904     if (reserve) preload_reserve( reserve );
 905     for (i = 0; preload_info[i].size; i++)
 906         wld_mmap( preload_info[i].addr, preload_info[i].size,
 907                   PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0 );
 908
 909     /* load the main binary */
 910     map_so_lib( argv[1], &main_binary_map );
 911
 912     /* load the ELF interpreter */
 913     interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
 914     map_so_lib( interp, &ld_so_map );
 915
 916     /* store pointer to the preload info into the appropriate main binary variable */
 917     wine_main_preload_info = find_symbol( main_binary_map.l_phdr, main_binary_map.l_phnum,
 918                                           "wine_main_preload_info" );
 919     if (wine_main_preload_info) *wine_main_preload_info = preload_info;
 920     else wld_printf( "wine_main_preload_info not found\n" );
 921
 922 #define SET_NEW_AV(n,type,val) new_av[n].a_type = (type); new_av[n].a_un.a_val = (val);
 923     SET_NEW_AV( 0, AT_PHDR, (unsigned long)main_binary_map.l_phdr );
 924     SET_NEW_AV( 1, AT_PHENT, sizeof(ElfW(Phdr)) );
 925     SET_NEW_AV( 2, AT_PHNUM, main_binary_map.l_phnum );
 926     SET_NEW_AV( 3, AT_PAGESZ, page_size );
 927     SET_NEW_AV( 4, AT_BASE, ld_so_map.l_addr );
 928     SET_NEW_AV( 5, AT_FLAGS, get_auxiliary( av, AT_FLAGS, 0 ) );
 929     SET_NEW_AV( 6, AT_ENTRY, main_binary_map.l_entry );
 930     SET_NEW_AV( 7, AT_UID, get_auxiliary( av, AT_UID, wld_getuid() ) );
 931     SET_NEW_AV( 8, AT_EUID, get_auxiliary( av, AT_EUID, wld_geteuid() ) );
 932     SET_NEW_AV( 9, AT_GID, get_auxiliary( av, AT_GID, wld_getgid() ) );
 933     SET_NEW_AV(10, AT_EGID, get_auxiliary( av, AT_EGID, wld_getegid() ) );
 934     SET_NEW_AV(11, AT_NULL, 0 );
 935 #undef SET_NEW_AV
 936
 937     i = 0;
 938     /* delete sysinfo values if addresses conflict */
 939     if (is_in_preload_range( av, AT_SYSINFO )) delete_av[i++].a_type = AT_SYSINFO;
 940     if (is_in_preload_range( av, AT_SYSINFO_EHDR )) delete_av[i++].a_type = AT_SYSINFO_EHDR;
 941     delete_av[i].a_type = AT_NULL;
 942
 943     /* get rid of first argument */
 944     pargc[1] = pargc[0] - 1;
 945     *stack = pargc + 1;
 946
 947     set_auxiliary_values( av, new_av, delete_av, stack );
 948
 949 #ifdef DUMP_AUX_INFO
 950     wld_printf("new stack = %x\n", *stack);
 951     wld_printf("jumping to %x\n", ld_so_map.l_entry);
 952 #endif
 953
 954     return (void *)ld_so_map.l_entry;
 955 }