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