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 #ifdef HAVE_SYS_STAT_H
  72 # include <sys/stat.h>
  73 #endif
  74 #include <fcntl.h>
  75 #ifdef HAVE_SYS_MMAN_H
  76 # include <sys/mman.h>
  77 #endif
  78 #ifdef HAVE_SYS_SYSCALL_H
  79 # include <sys/syscall.h>
  80 #endif
  81 #ifdef HAVE_UNISTD_H
  82 # include <unistd.h>
  83 #endif
  84 #ifdef HAVE_ELF_H
  85 # include <elf.h>
  86 #endif
  87 #ifdef HAVE_LINK_H
  88 # include <link.h>
  89 #endif
  90 #ifdef HAVE_SYS_LINK_H
  91 # include <sys/link.h>
  92 #endif
  93
  94 #include "main.h"
  95
  96 /* ELF definitions */
  97 #define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
  98 #define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
  99
 100 #define MAP_BASE_ADDR(l)     0
 101
 102 #ifndef MAP_COPY
 103 #define MAP_COPY MAP_PRIVATE
 104 #endif
 105 #ifndef MAP_NORESERVE
 106 #define MAP_NORESERVE 0
 107 #endif
 108
 109 static struct wine_preload_info preload_info[] =
 110 {
 111     { (void *)0x00000000, 0x00110000 },  /* DOS area */
 112     { (void *)0x7ffe0000, 0x01020000 },  /* shared user data + shared heap */
 113     { (void *)0x00110000, 0x1fef0000 },  /* PE exe range (may be set with WINEPRELOADRESERVE), defaults to 512mb */
 114     { 0, 0 }                             /* end of list */
 115 };
 116
 117 /* debugging */
 118 #undef DUMP_SEGMENTS
 119 #undef DUMP_AUX_INFO
 120 #undef DUMP_SYMS
 121
 122 /* older systems may not define these */
 123 #ifndef PT_TLS
 124 #define PT_TLS 7
 125 #endif
 126
 127 #ifndef AT_SYSINFO
 128 #define AT_SYSINFO 32
 129 #endif
 130 #ifndef AT_SYSINFO_EHDR
 131 #define AT_SYSINFO_EHDR 33
 132 #endif
 133
 134 static unsigned int page_size, page_mask;
 135 static char *preloader_start, *preloader_end;
 136
 137 struct wld_link_map {
 138     ElfW(Addr) l_addr;
 139     ElfW(Dyn) *l_ld;
 140     ElfW(Phdr)*l_phdr;
 141     ElfW(Addr) l_entry;
 142     ElfW(Half) l_ldnum;
 143     ElfW(Half) l_phnum;
 144     ElfW(Addr) l_map_start, l_map_end;
 145     ElfW(Addr) l_interp;
 146 };
 147
 148
 149 /*
 150  * The __bb_init_func is an empty function only called when file is
 151  * compiled with gcc flags "-fprofile-arcs -ftest-coverage".  This
 152  * function is normally provided by libc's startup files, but since we
 153  * build the preloader with "-nostartfiles -nodefaultlibs", we have to
 154  * provide our own (empty) version, otherwise linker fails.
 155  */
 156 void __bb_init_func(void) { return; }
 157
 158 /* similar to the above but for -fstack-protector */
 159 void *__stack_chk_guard = 0;
 160 void __stack_chk_fail(void) { return; }
 161
 162 /*
 163  * The _start function is the entry and exit point of this program
 164  *
 165  *  It calls wld_start, passing a pointer to the args it receives
 166  *  then jumps to the address wld_start returns.
 167  */
 168 void _start();
 169 extern char _end[];
 170 __ASM_GLOBAL_FUNC(_start,
 171                   "\tmovl %esp,%eax\n"
 172                   "\tleal -136(%esp),%esp\n"  /* allocate some space for extra aux values */
 173                   "\tpushl %eax\n"            /* orig stack pointer */
 174                   "\tpushl %esp\n"            /* ptr to orig stack pointer */
 175                   "\tcall wld_start\n"
 176                   "\tpopl %ecx\n"             /* remove ptr to stack pointer */
 177                   "\tpopl %esp\n"             /* new stack pointer */
 178                   "\tpush %eax\n"             /* ELF interpreter entry point */
 179                   "\txor %eax,%eax\n"
 180                   "\txor %ecx,%ecx\n"
 181                   "\txor %edx,%edx\n"
 182                   "\tret\n")
 183
 184 /* wrappers for Linux system calls */
 185
 186 #define SYSCALL_RET(ret) (((ret) < 0 && (ret) > -4096) ? -1 : (ret))
 187
 188 static inline __attribute__((noreturn)) void wld_exit( int code )
 189 {
 190     for (;;)  /* avoid warning */
 191         __asm__ __volatile__( "pushl %%ebx; movl %1,%%ebx; int $0x80; popl %%ebx"
 192                               : : "a" (SYS_exit), "r" (code) );
 193 }
 194
 195 static inline int wld_open( const char *name, int flags )
 196 {
 197     int ret;
 198     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 199                           : "=a" (ret) : "0" (SYS_open), "r" (name), "c" (flags) );
 200     return SYSCALL_RET(ret);
 201 }
 202
 203 static inline int wld_close( int fd )
 204 {
 205     int ret;
 206     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 207                           : "=a" (ret) : "0" (SYS_close), "r" (fd) );
 208     return SYSCALL_RET(ret);
 209 }
 210
 211 static inline ssize_t wld_read( int fd, void *buffer, size_t len )
 212 {
 213     int ret;
 214     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 215                           : "=a" (ret)
 216                           : "0" (SYS_read), "r" (fd), "c" (buffer), "d" (len)
 217                           : "memory" );
 218     return SYSCALL_RET(ret);
 219 }
 220
 221 static inline ssize_t wld_write( int fd, const void *buffer, size_t len )
 222 {
 223     int ret;
 224     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 225                           : "=a" (ret) : "0" (SYS_write), "r" (fd), "c" (buffer), "d" (len) );
 226     return SYSCALL_RET(ret);
 227 }
 228
 229 static inline int wld_mprotect( const void *addr, size_t len, int prot )
 230 {
 231     int ret;
 232     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 233                           : "=a" (ret) : "0" (SYS_mprotect), "r" (addr), "c" (len), "d" (prot) );
 234     return SYSCALL_RET(ret);
 235 }
 236
 237 static void *wld_mmap( void *start, size_t len, int prot, int flags, int fd, off_t offset )
 238 {
 239     int ret;
 240
 241     struct
 242     {
 243         void        *addr;
 244         unsigned int length;
 245         unsigned int prot;
 246         unsigned int flags;
 247         unsigned int fd;
 248         unsigned int offset;
 249     } args;
 250
 251     args.addr   = start;
 252     args.length = len;
 253     args.prot   = prot;
 254     args.flags  = flags;
 255     args.fd     = fd;
 256     args.offset = offset;
 257     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 258                           : "=a" (ret) : "0" (SYS_mmap), "q" (&args) : "memory" );
 259     return (void *)SYSCALL_RET(ret);
 260 }
 261
 262 static inline uid_t wld_getuid(void)
 263 {
 264     uid_t ret;
 265     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getuid) );
 266     return ret;
 267 }
 268
 269 static inline uid_t wld_geteuid(void)
 270 {
 271     uid_t ret;
 272     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_geteuid) );
 273     return ret;
 274 }
 275
 276 static inline gid_t wld_getgid(void)
 277 {
 278     gid_t ret;
 279     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getgid) );
 280     return ret;
 281 }
 282
 283 static inline gid_t wld_getegid(void)
 284 {
 285     gid_t ret;
 286     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getegid) );
 287     return ret;
 288 }
 289
 290 static inline int wld_prctl( int code, int arg )
 291 {
 292     int ret;
 293     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 294                           : "=a" (ret) : "0" (SYS_prctl), "r" (code), "c" (arg) );
 295     return SYSCALL_RET(ret);
 296 }
 297
 298
 299 /* replacement for libc functions */
 300
 301 static int wld_strcmp( const char *str1, const char *str2 )
 302 {
 303     while (*str1 && (*str1 == *str2)) { str1++; str2++; }
 304     return *str1 - *str2;
 305 }
 306
 307 static int wld_strncmp( const char *str1, const char *str2, size_t len )
 308 {
 309     if (len <= 0) return 0;
 310     while ((--len > 0) && *str1 && (*str1 == *str2)) { str1++; str2++; }
 311     return *str1 - *str2;
 312 }
 313
 314 static inline void *wld_memset( void *dest, int val, size_t len )
 315 {
 316     char *dst = dest;
 317     while (len--) *dst++ = val;
 318     return dest;
 319 }
 320
 321 /*
 322  * wld_printf - just the basics
 323  *
 324  *  %x prints a hex number
 325  *  %s prints a string
 326  */
 327 static int wld_vsprintf(char *buffer, const char *fmt, va_list args )
 328 {
 329     static const char hex_chars[16] = "0123456789abcdef";
 330     const char *p = fmt;
 331     char *str = buffer;
 332
 333     while( *p )
 334     {
 335         if( *p == '%' )
 336         {
 337             p++;
 338             if( *p == 'x' )
 339             {
 340                 int i;
 341                 unsigned int x = va_arg( args, unsigned int );
 342                 for(i=7; i>=0; i--)
 343                     *str++ = hex_chars[(x>>(i*4))&0xf];
 344             }
 345             else if( *p == 's' )
 346             {
 347                 char *s = va_arg( args, char * );
 348                 while(*s)
 349                     *str++ = *s++;
 350             }
 351             else if( *p == 0 )
 352                 break;
 353             p++;
 354         }
 355         *str++ = *p++;
 356     }
 357     *str = 0;
 358     return str - buffer;
 359 }
 360
 361 static void wld_printf(const char *fmt, ... )
 362 {
 363     va_list args;
 364     char buffer[256];
 365     int len;
 366
 367     va_start( args, fmt );
 368     len = wld_vsprintf(buffer, fmt, args );
 369     va_end( args );
 370     wld_write(2, buffer, len);
 371 }
 372
 373 static __attribute__((noreturn)) void fatal_error(const char *fmt, ... )
 374 {
 375     va_list args;
 376     char buffer[256];
 377     int len;
 378
 379     va_start( args, fmt );
 380     len = wld_vsprintf(buffer, fmt, args );
 381     va_end( args );
 382     wld_write(2, buffer, len);
 383     wld_exit(1);
 384 }
 385
 386 #ifdef DUMP_AUX_INFO
 387 /*
 388  *  Dump interesting bits of the ELF auxv_t structure that is passed
 389  *   as the 4th parameter to the _start function
 390  */
 391 static void dump_auxiliary( ElfW(auxv_t) *av )
 392 {
 393 #define NAME(at) { at, #at }
 394     static const struct { int val; const char *name; } names[] =
 395     {
 396         NAME(AT_BASE),
 397         NAME(AT_CLKTCK),
 398         NAME(AT_EGID),
 399         NAME(AT_ENTRY),
 400         NAME(AT_EUID),
 401         NAME(AT_FLAGS),
 402         NAME(AT_GID),
 403         NAME(AT_HWCAP),
 404         NAME(AT_PAGESZ),
 405         NAME(AT_PHDR),
 406         NAME(AT_PHENT),
 407         NAME(AT_PHNUM),
 408         NAME(AT_PLATFORM),
 409         NAME(AT_SYSINFO),
 410         NAME(AT_SYSINFO_EHDR),
 411         NAME(AT_UID),
 412         { 0, NULL }
 413     };
 414 #undef NAME
 415
 416     int i;
 417
 418     for (  ; av->a_type != AT_NULL; av++)
 419     {
 420         for (i = 0; names[i].name; i++) if (names[i].val == av->a_type) break;
 421         if (names[i].name) wld_printf("%s = %x\n", names[i].name, av->a_un.a_val);
 422         else wld_printf( "%x = %x\n", av->a_type, av->a_un.a_val );
 423     }
 424 }
 425 #endif
 426
 427 /*
 428  * set_auxiliary_values
 429  *
 430  * Set the new auxiliary values
 431  */
 432 static void set_auxiliary_values( ElfW(auxv_t) *av, const ElfW(auxv_t) *new_av,
 433                                   const ElfW(auxv_t) *delete_av, void **stack )
 434 {
 435     int i, j, av_count = 0, new_count = 0, delete_count = 0;
 436     char *src, *dst;
 437
 438     /* count how many aux values we have already */
 439     while (av[av_count].a_type != AT_NULL) av_count++;
 440
 441     /* delete unwanted values */
 442     for (j = 0; delete_av[j].a_type != AT_NULL; j++)
 443     {
 444         for (i = 0; i < av_count; i++) if (av[i].a_type == delete_av[j].a_type)
 445         {
 446             av[i].a_type = av[av_count-1].a_type;
 447             av[i].a_un.a_val = av[av_count-1].a_un.a_val;
 448             av[--av_count].a_type = AT_NULL;
 449             delete_count++;
 450             break;
 451         }
 452     }
 453
 454     /* count how many values we have in new_av that aren't in av */
 455     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 456     {
 457         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 458         if (i == av_count) new_count++;
 459     }
 460
 461     src = (char *)*stack;
 462     dst = src - (new_count - delete_count) * sizeof(*av);
 463     if (new_count > delete_count)   /* need to make room for the extra values */
 464     {
 465         int len = (char *)(av + av_count + 1) - src;
 466         for (i = 0; i < len; i++) dst[i] = src[i];
 467     }
 468     else if (new_count < delete_count)  /* get rid of unused values */
 469     {
 470         int len = (char *)(av + av_count + 1) - dst;
 471         for (i = len - 1; i >= 0; i--) dst[i] = src[i];
 472     }
 473     *stack = dst;
 474     av -= (new_count - delete_count);
 475
 476     /* now set the values */
 477     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 478     {
 479         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 480         if (i < av_count) av[i].a_un.a_val = new_av[j].a_un.a_val;
 481         else
 482         {
 483             av[av_count].a_type     = new_av[j].a_type;
 484             av[av_count].a_un.a_val = new_av[j].a_un.a_val;
 485             av_count++;
 486         }
 487     }
 488
 489 #ifdef DUMP_AUX_INFO
 490     wld_printf("New auxiliary info:\n");
 491     dump_auxiliary( av );
 492 #endif
 493 }
 494
 495 /*
 496  * get_auxiliary
 497  *
 498  * Get a field of the auxiliary structure
 499  */
 500 static int get_auxiliary( ElfW(auxv_t) *av, int type, int def_val )
 501 {
 502   for ( ; av->a_type != AT_NULL; av++)
 503       if( av->a_type == type ) return av->a_un.a_val;
 504   return def_val;
 505 }
 506
 507 /*
 508  * map_so_lib
 509  *
 510  * modelled after _dl_map_object_from_fd() from glibc-2.3.1/elf/dl-load.c
 511  *
 512  * This function maps the segments from an ELF object, and optionally
 513  *  stores information about the mapping into the auxv_t structure.
 514  */
 515 static void map_so_lib( const char *name, struct wld_link_map *l)
 516 {
 517     int fd;
 518     unsigned char buf[0x800];
 519     ElfW(Ehdr) *header = (ElfW(Ehdr)*)buf;
 520     ElfW(Phdr) *phdr, *ph;
 521     /* Scan the program header table, collecting its load commands.  */
 522     struct loadcmd
 523       {
 524         ElfW(Addr) mapstart, mapend, dataend, allocend;
 525         off_t mapoff;
 526         int prot;
 527       } loadcmds[16], *c;
 528     size_t nloadcmds = 0, maplength;
 529
 530     fd = wld_open( name, O_RDONLY );
 531     if (fd == -1) fatal_error("%s: could not open\n", name );
 532
 533     if (wld_read( fd, buf, sizeof(buf) ) != sizeof(buf))
 534         fatal_error("%s: failed to read ELF header\n", name);
 535
 536     phdr = (void*) (((unsigned char*)buf) + header->e_phoff);
 537
 538     if( ( header->e_ident[0] != 0x7f ) ||
 539         ( header->e_ident[1] != 'E' ) ||
 540         ( header->e_ident[2] != 'L' ) ||
 541         ( header->e_ident[3] != 'F' ) )
 542         fatal_error( "%s: not an ELF binary... don't know how to load it\n", name );
 543
 544     if( header->e_machine != EM_386 )
 545         fatal_error("%s: not an i386 ELF binary... don't know how to load it\n", name );
 546
 547     if (header->e_phnum > sizeof(loadcmds)/sizeof(loadcmds[0]))
 548         fatal_error( "%s: oops... not enough space for load commands\n", name );
 549
 550     maplength = header->e_phnum * sizeof (ElfW(Phdr));
 551     if (header->e_phoff + maplength > sizeof(buf))
 552         fatal_error( "%s: oops... not enough space for ELF headers\n", name );
 553
 554     l->l_ld = 0;
 555     l->l_addr = 0;
 556     l->l_phdr = 0;
 557     l->l_phnum = header->e_phnum;
 558     l->l_entry = header->e_entry;
 559     l->l_interp = 0;
 560
 561     for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
 562     {
 563
 564 #ifdef DUMP_SEGMENTS
 565       wld_printf( "ph = %x\n", ph );
 566       wld_printf( " p_type   = %x\n", ph->p_type );
 567       wld_printf( " p_flags  = %x\n", ph->p_flags );
 568       wld_printf( " p_offset = %x\n", ph->p_offset );
 569       wld_printf( " p_vaddr  = %x\n", ph->p_vaddr );
 570       wld_printf( " p_paddr  = %x\n", ph->p_paddr );
 571       wld_printf( " p_filesz = %x\n", ph->p_filesz );
 572       wld_printf( " p_memsz  = %x\n", ph->p_memsz );
 573       wld_printf( " p_align  = %x\n", ph->p_align );
 574 #endif
 575
 576       switch (ph->p_type)
 577         {
 578           /* These entries tell us where to find things once the file's
 579              segments are mapped in.  We record the addresses it says
 580              verbatim, and later correct for the run-time load address.  */
 581         case PT_DYNAMIC:
 582           l->l_ld = (void *) ph->p_vaddr;
 583           l->l_ldnum = ph->p_memsz / sizeof (Elf32_Dyn);
 584           break;
 585
 586         case PT_PHDR:
 587           l->l_phdr = (void *) ph->p_vaddr;
 588           break;
 589
 590         case PT_LOAD:
 591           {
 592             if ((ph->p_align & page_mask) != 0)
 593               fatal_error( "%s: ELF load command alignment not page-aligned\n", name );
 594
 595             if (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)
 596               fatal_error( "%s: ELF load command address/offset not properly aligned\n", name );
 597
 598             c = &loadcmds[nloadcmds++];
 599             c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
 600             c->mapend = ((ph->p_vaddr + ph->p_filesz + page_mask) & ~page_mask);
 601             c->dataend = ph->p_vaddr + ph->p_filesz;
 602             c->allocend = ph->p_vaddr + ph->p_memsz;
 603             c->mapoff = ph->p_offset & ~(ph->p_align - 1);
 604
 605             c->prot = 0;
 606             if (ph->p_flags & PF_R)
 607               c->prot |= PROT_READ;
 608             if (ph->p_flags & PF_W)
 609               c->prot |= PROT_WRITE;
 610             if (ph->p_flags & PF_X)
 611               c->prot |= PROT_EXEC;
 612           }
 613           break;
 614
 615         case PT_INTERP:
 616           l->l_interp = ph->p_vaddr;
 617           break;
 618
 619         case PT_TLS:
 620           /*
 621            * We don't need to set anything up because we're
 622            * emulating the kernel, not ld-linux.so.2
 623            * The ELF loader will set up the TLS data itself.
 624            */
 625         case PT_SHLIB:
 626         case PT_NOTE:
 627         default:
 628           break;
 629         }
 630     }
 631
 632     /* Now process the load commands and map segments into memory.  */
 633     c = loadcmds;
 634
 635     /* Length of the sections to be loaded.  */
 636     maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
 637
 638     if( header->e_type == ET_DYN )
 639     {
 640         ElfW(Addr) mappref;
 641         mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
 642                    - MAP_BASE_ADDR (l));
 643
 644         /* Remember which part of the address space this object uses.  */
 645         l->l_map_start = (ElfW(Addr)) wld_mmap ((void *) mappref, maplength,
 646                                               c->prot, MAP_COPY | MAP_FILE,
 647                                               fd, c->mapoff);
 648         /* wld_printf("set  : offset = %x\n", c->mapoff); */
 649         /* wld_printf("l->l_map_start = %x\n", l->l_map_start); */
 650
 651         l->l_map_end = l->l_map_start + maplength;
 652         l->l_addr = l->l_map_start - c->mapstart;
 653
 654         wld_mprotect ((caddr_t) (l->l_addr + c->mapend),
 655                     loadcmds[nloadcmds - 1].allocend - c->mapend,
 656                     PROT_NONE);
 657         goto postmap;
 658     }
 659     else
 660     {
 661         /* sanity check */
 662         if ((char *)c->mapstart + maplength > preloader_start &&
 663             (char *)c->mapstart <= preloader_end)
 664             fatal_error( "%s: binary overlaps preloader (%x-%x)\n",
 665                          name, c->mapstart, (char *)c->mapstart + maplength );
 666
 667         ELF_FIXED_ADDRESS (loader, c->mapstart);
 668     }
 669
 670     /* Remember which part of the address space this object uses.  */
 671     l->l_map_start = c->mapstart + l->l_addr;
 672     l->l_map_end = l->l_map_start + maplength;
 673
 674     while (c < &loadcmds[nloadcmds])
 675       {
 676         if (c->mapend > c->mapstart)
 677             /* Map the segment contents from the file.  */
 678             wld_mmap ((void *) (l->l_addr + c->mapstart),
 679                         c->mapend - c->mapstart, c->prot,
 680                         MAP_FIXED | MAP_COPY | MAP_FILE, fd, c->mapoff);
 681
 682       postmap:
 683         if (l->l_phdr == 0
 684             && (ElfW(Off)) c->mapoff <= header->e_phoff
 685             && ((size_t) (c->mapend - c->mapstart + c->mapoff)
 686                 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
 687           /* Found the program header in this segment.  */
 688           l->l_phdr = (void *)(unsigned int) (c->mapstart + header->e_phoff - c->mapoff);
 689
 690         if (c->allocend > c->dataend)
 691           {
 692             /* Extra zero pages should appear at the end of this segment,
 693                after the data mapped from the file.   */
 694             ElfW(Addr) zero, zeroend, zeropage;
 695
 696             zero = l->l_addr + c->dataend;
 697             zeroend = l->l_addr + c->allocend;
 698             zeropage = (zero + page_mask) & ~page_mask;
 699
 700             /*
 701              * This is different from the dl-load load...
 702              *  ld-linux.so.2 relies on the whole page being zero'ed
 703              */
 704             zeroend = (zeroend + page_mask) & ~page_mask;
 705
 706             if (zeroend < zeropage)
 707             {
 708               /* All the extra data is in the last page of the segment.
 709                  We can just zero it.  */
 710               zeropage = zeroend;
 711             }
 712
 713             if (zeropage > zero)
 714               {
 715                 /* Zero the final part of the last page of the segment.  */
 716                 if ((c->prot & PROT_WRITE) == 0)
 717                   {
 718                     /* Dag nab it.  */
 719                     wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot|PROT_WRITE);
 720                   }
 721                 wld_memset ((void *) zero, '\0', zeropage - zero);
 722                 if ((c->prot & PROT_WRITE) == 0)
 723                   wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot);
 724               }
 725
 726             if (zeroend > zeropage)
 727               {
 728                 /* Map the remaining zero pages in from the zero fill FD.  */
 729                 caddr_t mapat;
 730                 mapat = wld_mmap ((caddr_t) zeropage, zeroend - zeropage,
 731                                 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
 732                                 -1, 0);
 733               }
 734           }
 735
 736         ++c;
 737       }
 738
 739     if (l->l_phdr == NULL) fatal_error("no program header\n");
 740
 741     l->l_phdr = (void *)((ElfW(Addr))l->l_phdr + l->l_addr);
 742     l->l_entry += l->l_addr;
 743
 744     wld_close( fd );
 745 }
 746
 747
 748 /*
 749  * Find a symbol in the symbol table of the executable loaded
 750  */
 751 static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var )
 752 {
 753     const ElfW(Dyn) *dyn = NULL;
 754     const ElfW(Phdr) *ph;
 755     const ElfW(Sym) *symtab = NULL;
 756     const char *strings = NULL;
 757     uint32_t i, symtabend = 0;
 758
 759     /* check the values */
 760 #ifdef DUMP_SYMS
 761     wld_printf("%x %x\n", phdr, num );
 762 #endif
 763     if( ( phdr == NULL ) || ( num == 0 ) )
 764     {
 765         wld_printf("could not find PT_DYNAMIC header entry\n");
 766         return NULL;
 767     }
 768
 769     /* parse the (already loaded) ELF executable's header */
 770     for (ph = phdr; ph < &phdr[num]; ++ph)
 771     {
 772         if( PT_DYNAMIC == ph->p_type )
 773         {
 774             dyn = (void *) ph->p_vaddr;
 775             num = ph->p_memsz / sizeof (Elf32_Dyn);
 776             break;
 777         }
 778     }
 779     if( !dyn ) return NULL;
 780
 781     while( dyn->d_tag )
 782     {
 783         if( dyn->d_tag == DT_STRTAB )
 784             strings = (const char*) dyn->d_un.d_ptr;
 785         if( dyn->d_tag == DT_SYMTAB )
 786             symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
 787         if( dyn->d_tag == DT_HASH )
 788             symtabend = *((const uint32_t *)dyn->d_un.d_ptr + 1);
 789 #ifdef DUMP_SYMS
 790         wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
 791 #endif
 792         dyn++;
 793     }
 794
 795     if( (!symtab) || (!strings) ) return NULL;
 796
 797     for (i = 0; i < symtabend; i++)
 798     {
 799         if( ( ELF32_ST_BIND(symtab[i].st_info) == STT_OBJECT ) &&
 800             ( 0 == wld_strcmp( strings+symtab[i].st_name, var ) ) )
 801         {
 802 #ifdef DUMP_SYMS
 803             wld_printf("Found %s -> %x\n", strings+symtab[i].st_name, symtab[i].st_value );
 804 #endif
 805             return (void*)symtab[i].st_value;
 806         }
 807     }
 808     return NULL;
 809 }
 810
 811 /*
 812  *  preload_reserve
 813  *
 814  * Reserve a range specified in string format
 815  */
 816 static void preload_reserve( const char *str )
 817 {
 818     const char *p;
 819     unsigned long result = 0;
 820     void *start = NULL, *end = NULL;
 821     int first = 1;
 822
 823     for (p = str; *p; p++)
 824     {
 825         if (*p >= '0' && *p <= '9') result = result * 16 + *p - '0';
 826         else if (*p >= 'a' && *p <= 'f') result = result * 16 + *p - 'a' + 10;
 827         else if (*p >= 'A' && *p <= 'F') result = result * 16 + *p - 'A' + 10;
 828         else if (*p == '-')
 829         {
 830             if (!first) goto error;
 831             start = (void *)(result & ~page_mask);
 832             result = 0;
 833             first = 0;
 834         }
 835         else goto error;
 836     }
 837     if (!first) end = (void *)((result + page_mask) & ~page_mask);
 838     else if (result) goto error;  /* single value '0' is allowed */
 839
 840     /* sanity checks */
 841     if (end <= start) start = end = NULL;
 842     else if ((char *)end > preloader_start &&
 843              (char *)start <= preloader_end)
 844     {
 845         wld_printf( "WINEPRELOADRESERVE range %x-%x overlaps preloader %x-%x\n",
 846                      start, end, preloader_start, preloader_end );
 847         start = end = NULL;
 848     }
 849
 850     /* entry 2 is for the PE exe */
 851     preload_info[2].addr = start;
 852     preload_info[2].size = (char *)end - (char *)start;
 853     return;
 854
 855 error:
 856     fatal_error( "invalid WINEPRELOADRESERVE value '%s'\n", str );
 857 }
 858
 859 /*
 860  *  is_in_preload_range
 861  *
 862  * Check if address of the given aux value is in one of the reserved ranges
 863  */
 864 static int is_in_preload_range( const ElfW(auxv_t) *av, int type )
 865 {
 866     int i;
 867
 868     while (av->a_type != type && av->a_type != AT_NULL) av++;
 869
 870     if (av->a_type == type)
 871     {
 872         for (i = 0; preload_info[i].size; i++)
 873         {
 874             if ((char *)av->a_un.a_val >= (char *)preload_info[i].addr &&
 875                 (char *)av->a_un.a_val < (char *)preload_info[i].addr + preload_info[i].size)
 876                 return 1;
 877         }
 878     }
 879     return 0;
 880 }
 881
 882 /* set the process name if supported */
 883 static void set_process_name( int argc, char *argv[] )
 884 {
 885     unsigned int i, off;
 886     char *p, *name, *end;
 887
 888     /* set the process short name */
 889     for (p = name = argv[1]; *p; p++) if (p[0] == '/' && p[1]) name = p + 1;
 890     if (wld_prctl( 15 /* PR_SET_NAME */, (int)name ) == -1) return;
 891
 892     /* find the end of the argv array and move everything down */
 893     end = argv[argc - 1];
 894     while (*end) end++;
 895     off = argv[1] - argv[0];
 896     for (p = argv[1]; p <= end; p++) *(p - off) = *p;
 897     wld_memset( end - off, 0, off );
 898     for (i = 1; i < argc; i++) argv[i] -= off;
 899 }
 900
 901
 902 /*
 903  *  wld_start
 904  *
 905  *  Repeat the actions the kernel would do when loading a dynamically linked .so
 906  *  Load the binary and then its ELF interpreter.
 907  *  Note, we assume that the binary is a dynamically linked ELF shared object.
 908  */
 909 void* wld_start( void **stack )
 910 {
 911     int i, *pargc;
 912     char **argv, **p;
 913     char *interp, *reserve = NULL;
 914     ElfW(auxv_t) new_av[12], delete_av[3], *av;
 915     struct wld_link_map main_binary_map, ld_so_map;
 916     struct wine_preload_info **wine_main_preload_info;
 917
 918     pargc = *stack;
 919     argv = (char **)pargc + 1;
 920     if (*pargc < 2) fatal_error( "Usage: %s wine_binary [args]\n", argv[0] );
 921
 922     /* skip over the parameters */
 923     p = argv + *pargc + 1;
 924
 925     /* skip over the environment */
 926     while (*p)
 927     {
 928         static const char res[] = "WINEPRELOADRESERVE=";
 929         if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p + sizeof(res) - 1;
 930         p++;
 931     }
 932
 933     av = (ElfW(auxv_t)*) (p+1);
 934     page_size = get_auxiliary( av, AT_PAGESZ, 4096 );
 935     page_mask = page_size - 1;
 936
 937     preloader_start = (char *)_start - ((unsigned int)_start & page_mask);
 938     preloader_end = (char *)((unsigned int)(_end + page_mask) & ~page_mask);
 939
 940 #ifdef DUMP_AUX_INFO
 941     wld_printf( "stack = %x\n", *stack );
 942     for( i = 0; i < *pargc; i++ ) wld_printf("argv[%x] = %s\n", i, argv[i]);
 943     dump_auxiliary( av );
 944 #endif
 945
 946     /* reserve memory that Wine needs */
 947     if (reserve) preload_reserve( reserve );
 948     for (i = 0; preload_info[i].size; i++)
 949         wld_mmap( preload_info[i].addr, preload_info[i].size,
 950                   PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0 );
 951
 952     /* add an executable page at the top of the address space to defeat
 953      * broken no-exec protections that play with the code selector limit */
 954     wld_mprotect( (char *)0x80000000 - page_size, page_size, PROT_EXEC | PROT_READ );
 955
 956     /* load the main binary */
 957     map_so_lib( argv[1], &main_binary_map );
 958
 959     /* load the ELF interpreter */
 960     interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
 961     map_so_lib( interp, &ld_so_map );
 962
 963     /* store pointer to the preload info into the appropriate main binary variable */
 964     wine_main_preload_info = find_symbol( main_binary_map.l_phdr, main_binary_map.l_phnum,
 965                                           "wine_main_preload_info" );
 966     if (wine_main_preload_info) *wine_main_preload_info = preload_info;
 967     else wld_printf( "wine_main_preload_info not found\n" );
 968
 969 #define SET_NEW_AV(n,type,val) new_av[n].a_type = (type); new_av[n].a_un.a_val = (val);
 970     SET_NEW_AV( 0, AT_PHDR, (unsigned long)main_binary_map.l_phdr );
 971     SET_NEW_AV( 1, AT_PHENT, sizeof(ElfW(Phdr)) );
 972     SET_NEW_AV( 2, AT_PHNUM, main_binary_map.l_phnum );
 973     SET_NEW_AV( 3, AT_PAGESZ, page_size );
 974     SET_NEW_AV( 4, AT_BASE, ld_so_map.l_addr );
 975     SET_NEW_AV( 5, AT_FLAGS, get_auxiliary( av, AT_FLAGS, 0 ) );
 976     SET_NEW_AV( 6, AT_ENTRY, main_binary_map.l_entry );
 977     SET_NEW_AV( 7, AT_UID, get_auxiliary( av, AT_UID, wld_getuid() ) );
 978     SET_NEW_AV( 8, AT_EUID, get_auxiliary( av, AT_EUID, wld_geteuid() ) );
 979     SET_NEW_AV( 9, AT_GID, get_auxiliary( av, AT_GID, wld_getgid() ) );
 980     SET_NEW_AV(10, AT_EGID, get_auxiliary( av, AT_EGID, wld_getegid() ) );
 981     SET_NEW_AV(11, AT_NULL, 0 );
 982 #undef SET_NEW_AV
 983
 984     i = 0;
 985     /* delete sysinfo values if addresses conflict */
 986     if (is_in_preload_range( av, AT_SYSINFO )) delete_av[i++].a_type = AT_SYSINFO;
 987     if (is_in_preload_range( av, AT_SYSINFO_EHDR )) delete_av[i++].a_type = AT_SYSINFO_EHDR;
 988     delete_av[i].a_type = AT_NULL;
 989
 990     /* get rid of first argument */
 991     set_process_name( *pargc, argv );
 992     pargc[1] = pargc[0] - 1;
 993     *stack = pargc + 1;
 994
 995     set_auxiliary_values( av, new_av, delete_av, stack );
 996
 997 #ifdef DUMP_AUX_INFO
 998     wld_printf("new stack = %x\n", *stack);
 999     wld_printf("jumping to %x\n", ld_so_map.l_entry);
1000 #endif
1001
1002     return (void *)ld_so_map.l_entry;
1003 }