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Sweden-Number/loader/preloader.c

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/*
* Preloader for ld.so
*
* Copyright (C) 1995,96,97,98,99,2000,2001,2002 Free Software Foundation, Inc.
* Copyright (C) 2004 Mike McCormack for CodeWeavers
* Copyright (C) 2004 Alexandre Julliard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
/*
* Design notes
*
* The goal of this program is to be a workaround for exec-shield, as used
* by the Linux kernel distributed with Fedora Core and other distros.
*
* To do this, we implement our own shared object loader that reserves memory
* that is important to Wine, and then loads the main binary and its ELF
* interpreter.
*
* We will try to set up the stack and memory area so that the program that
* loads after us (eg. the wine binary) never knows we were here, except that
* areas of memory it needs are already magically reserved.
*
* The following memory areas are important to Wine:
* 0x00000000 - 0x00110000 the DOS area
* 0x80000000 - 0x81000000 the shared heap
* ??? - ??? the PE binary load address (usually starting at 0x00400000)
*
* If this program is used as the shared object loader, the only difference
* that the loaded programs should see is that this loader will be mapped
* into memory when it starts.
*/
/*
* References (things I consulted to understand how ELF loading works):
*
* glibc 2.3.2 elf/dl-load.c
* http://www.gnu.org/directory/glibc.html
*
* Linux 2.6.4 fs/binfmt_elf.c
* ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.4.tar.bz2
*
* Userland exec, by <grugq@hcunix.net>
* http://cert.uni-stuttgart.de/archive/bugtraq/2004/01/msg00002.html
*
* The ELF specification:
* http://www.linuxbase.org/spec/booksets/LSB-Embedded/LSB-Embedded/book387.html
*/
#include "config.h"
#include "wine/port.h"
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#include <fcntl.h>
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif
#ifdef HAVE_SYS_SYSCALL_H
# include <sys/syscall.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_ELF_H
# include <elf.h>
#endif
#ifdef HAVE_LINK_H
# include <link.h>
#endif
#ifdef HAVE_SYS_LINK_H
# include <sys/link.h>
#endif
#include "main.h"
/* ELF definitions */
#define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
#define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
#define MAP_BASE_ADDR(l) 0
#ifndef MAP_COPY
#define MAP_COPY MAP_PRIVATE
#endif
#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
static struct wine_preload_info preload_info[] =
{
{ (void *)0x00000000, 0x60000000 }, /* low memory area */
{ (void *)0x7f000000, 0x02000000 }, /* top-down allocations + shared heap */
{ 0, 0 }, /* PE exe range set with WINEPRELOADRESERVE */
{ 0, 0 } /* end of list */
};
/* debugging */
#undef DUMP_SEGMENTS
#undef DUMP_AUX_INFO
#undef DUMP_SYMS
/* older systems may not define these */
#ifndef PT_TLS
#define PT_TLS 7
#endif
#ifndef AT_SYSINFO
#define AT_SYSINFO 32
#endif
#ifndef AT_SYSINFO_EHDR
#define AT_SYSINFO_EHDR 33
#endif
#ifndef DT_GNU_HASH
#define DT_GNU_HASH 0x6ffffef5
#endif
static unsigned int page_size, page_mask;
static char *preloader_start, *preloader_end;
struct wld_link_map {
ElfW(Addr) l_addr;
ElfW(Dyn) *l_ld;
ElfW(Phdr)*l_phdr;
ElfW(Addr) l_entry;
ElfW(Half) l_ldnum;
ElfW(Half) l_phnum;
ElfW(Addr) l_map_start, l_map_end;
ElfW(Addr) l_interp;
};
/*
* The __bb_init_func is an empty function only called when file is
* compiled with gcc flags "-fprofile-arcs -ftest-coverage". This
* function is normally provided by libc's startup files, but since we
* build the preloader with "-nostartfiles -nodefaultlibs", we have to
* provide our own (empty) version, otherwise linker fails.
*/
void __bb_init_func(void) { return; }
/* similar to the above but for -fstack-protector */
void *__stack_chk_guard = 0;
void __stack_chk_fail(void) { return; }
/*
* The _start function is the entry and exit point of this program
*
* It calls wld_start, passing a pointer to the args it receives
* then jumps to the address wld_start returns.
*/
void _start();
extern char _end[];
__ASM_GLOBAL_FUNC(_start,
"\tmovl %esp,%eax\n"
"\tleal -136(%esp),%esp\n" /* allocate some space for extra aux values */
"\tpushl %eax\n" /* orig stack pointer */
"\tpushl %esp\n" /* ptr to orig stack pointer */
"\tcall wld_start\n"
"\tpopl %ecx\n" /* remove ptr to stack pointer */
"\tpopl %esp\n" /* new stack pointer */
"\tpush %eax\n" /* ELF interpreter entry point */
"\txor %eax,%eax\n"
"\txor %ecx,%ecx\n"
"\txor %edx,%edx\n"
"\tret\n")
/* wrappers for Linux system calls */
#define SYSCALL_RET(ret) (((ret) < 0 && (ret) > -4096) ? -1 : (ret))
static inline __attribute__((noreturn)) void wld_exit( int code )
{
for (;;) /* avoid warning */
__asm__ __volatile__( "pushl %%ebx; movl %1,%%ebx; int $0x80; popl %%ebx"
: : "a" (SYS_exit), "r" (code) );
}
static inline int wld_open( const char *name, int flags )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_open), "r" (name), "c" (flags) );
return SYSCALL_RET(ret);
}
static inline int wld_close( int fd )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_close), "r" (fd) );
return SYSCALL_RET(ret);
}
static inline ssize_t wld_read( int fd, void *buffer, size_t len )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret)
: "0" (SYS_read), "r" (fd), "c" (buffer), "d" (len)
: "memory" );
return SYSCALL_RET(ret);
}
static inline ssize_t wld_write( int fd, const void *buffer, size_t len )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_write), "r" (fd), "c" (buffer), "d" (len) );
return SYSCALL_RET(ret);
}
static inline int wld_mprotect( const void *addr, size_t len, int prot )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_mprotect), "r" (addr), "c" (len), "d" (prot) );
return SYSCALL_RET(ret);
}
static void *wld_mmap( void *start, size_t len, int prot, int flags, int fd, off_t offset )
{
int ret;
struct
{
void *addr;
unsigned int length;
unsigned int prot;
unsigned int flags;
unsigned int fd;
unsigned int offset;
} args;
args.addr = start;
args.length = len;
args.prot = prot;
args.flags = flags;
args.fd = fd;
args.offset = offset;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_mmap), "q" (&args) : "memory" );
return (void *)SYSCALL_RET(ret);
}
static inline uid_t wld_getuid(void)
{
uid_t ret;
__asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getuid) );
return ret;
}
static inline uid_t wld_geteuid(void)
{
uid_t ret;
__asm__( "int $0x80" : "=a" (ret) : "0" (SYS_geteuid) );
return ret;
}
static inline gid_t wld_getgid(void)
{
gid_t ret;
__asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getgid) );
return ret;
}
static inline gid_t wld_getegid(void)
{
gid_t ret;
__asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getegid) );
return ret;
}
static inline int wld_prctl( int code, int arg )
{
int ret;
__asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
: "=a" (ret) : "0" (SYS_prctl), "r" (code), "c" (arg) );
return SYSCALL_RET(ret);
}
/* replacement for libc functions */
static int wld_strcmp( const char *str1, const char *str2 )
{
while (*str1 && (*str1 == *str2)) { str1++; str2++; }
return *str1 - *str2;
}
static int wld_strncmp( const char *str1, const char *str2, size_t len )
{
if (len <= 0) return 0;
while ((--len > 0) && *str1 && (*str1 == *str2)) { str1++; str2++; }
return *str1 - *str2;
}
static inline void *wld_memset( void *dest, int val, size_t len )
{
char *dst = dest;
while (len--) *dst++ = val;
return dest;
}
/*
* wld_printf - just the basics
*
* %x prints a hex number
* %s prints a string
*/
static int wld_vsprintf(char *buffer, const char *fmt, va_list args )
{
static const char hex_chars[16] = "0123456789abcdef";
const char *p = fmt;
char *str = buffer;
while( *p )
{
if( *p == '%' )
{
p++;
if( *p == 'x' )
{
int i;
unsigned int x = va_arg( args, unsigned int );
for(i=7; i>=0; i--)
*str++ = hex_chars[(x>>(i*4))&0xf];
}
else if( *p == 's' )
{
char *s = va_arg( args, char * );
while(*s)
*str++ = *s++;
}
else if( *p == 0 )
break;
p++;
}
*str++ = *p++;
}
*str = 0;
return str - buffer;
}
static void wld_printf(const char *fmt, ... )
{
va_list args;
char buffer[256];
int len;
va_start( args, fmt );
len = wld_vsprintf(buffer, fmt, args );
va_end( args );
wld_write(2, buffer, len);
}
static __attribute__((noreturn)) void fatal_error(const char *fmt, ... )
{
va_list args;
char buffer[256];
int len;
va_start( args, fmt );
len = wld_vsprintf(buffer, fmt, args );
va_end( args );
wld_write(2, buffer, len);
wld_exit(1);
}
#ifdef DUMP_AUX_INFO
/*
* Dump interesting bits of the ELF auxv_t structure that is passed
* as the 4th parameter to the _start function
*/
static void dump_auxiliary( ElfW(auxv_t) *av )
{
#define NAME(at) { at, #at }
static const struct { int val; const char *name; } names[] =
{
NAME(AT_BASE),
NAME(AT_CLKTCK),
NAME(AT_EGID),
NAME(AT_ENTRY),
NAME(AT_EUID),
NAME(AT_FLAGS),
NAME(AT_GID),
NAME(AT_HWCAP),
NAME(AT_PAGESZ),
NAME(AT_PHDR),
NAME(AT_PHENT),
NAME(AT_PHNUM),
NAME(AT_PLATFORM),
NAME(AT_SYSINFO),
NAME(AT_SYSINFO_EHDR),
NAME(AT_UID),
{ 0, NULL }
};
#undef NAME
int i;
for ( ; av->a_type != AT_NULL; av++)
{
for (i = 0; names[i].name; i++) if (names[i].val == av->a_type) break;
if (names[i].name) wld_printf("%s = %x\n", names[i].name, av->a_un.a_val);
else wld_printf( "%x = %x\n", av->a_type, av->a_un.a_val );
}
}
#endif
/*
* set_auxiliary_values
*
* Set the new auxiliary values
*/
static void set_auxiliary_values( ElfW(auxv_t) *av, const ElfW(auxv_t) *new_av,
const ElfW(auxv_t) *delete_av, void **stack )
{
int i, j, av_count = 0, new_count = 0, delete_count = 0;
char *src, *dst;
/* count how many aux values we have already */
while (av[av_count].a_type != AT_NULL) av_count++;
/* delete unwanted values */
for (j = 0; delete_av[j].a_type != AT_NULL; j++)
{
for (i = 0; i < av_count; i++) if (av[i].a_type == delete_av[j].a_type)
{
av[i].a_type = av[av_count-1].a_type;
av[i].a_un.a_val = av[av_count-1].a_un.a_val;
av[--av_count].a_type = AT_NULL;
delete_count++;
break;
}
}
/* count how many values we have in new_av that aren't in av */
for (j = 0; new_av[j].a_type != AT_NULL; j++)
{
for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
if (i == av_count) new_count++;
}
src = (char *)*stack;
dst = src - (new_count - delete_count) * sizeof(*av);
if (new_count > delete_count) /* need to make room for the extra values */
{
int len = (char *)(av + av_count + 1) - src;
for (i = 0; i < len; i++) dst[i] = src[i];
}
else if (new_count < delete_count) /* get rid of unused values */
{
int len = (char *)(av + av_count + 1) - dst;
for (i = len - 1; i >= 0; i--) dst[i] = src[i];
}
*stack = dst;
av -= (new_count - delete_count);
/* now set the values */
for (j = 0; new_av[j].a_type != AT_NULL; j++)
{
for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
if (i < av_count) av[i].a_un.a_val = new_av[j].a_un.a_val;
else
{
av[av_count].a_type = new_av[j].a_type;
av[av_count].a_un.a_val = new_av[j].a_un.a_val;
av_count++;
}
}
#ifdef DUMP_AUX_INFO
wld_printf("New auxiliary info:\n");
dump_auxiliary( av );
#endif
}
/*
* get_auxiliary
*
* Get a field of the auxiliary structure
*/
static int get_auxiliary( ElfW(auxv_t) *av, int type, int def_val )
{
for ( ; av->a_type != AT_NULL; av++)
if( av->a_type == type ) return av->a_un.a_val;
return def_val;
}
/*
* map_so_lib
*
* modelled after _dl_map_object_from_fd() from glibc-2.3.1/elf/dl-load.c
*
* This function maps the segments from an ELF object, and optionally
* stores information about the mapping into the auxv_t structure.
*/
static void map_so_lib( const char *name, struct wld_link_map *l)
{
int fd;
unsigned char buf[0x800];
ElfW(Ehdr) *header = (ElfW(Ehdr)*)buf;
ElfW(Phdr) *phdr, *ph;
/* Scan the program header table, collecting its load commands. */
struct loadcmd
{
ElfW(Addr) mapstart, mapend, dataend, allocend;
off_t mapoff;
int prot;
} loadcmds[16], *c;
size_t nloadcmds = 0, maplength;
fd = wld_open( name, O_RDONLY );
if (fd == -1) fatal_error("%s: could not open\n", name );
if (wld_read( fd, buf, sizeof(buf) ) != sizeof(buf))
fatal_error("%s: failed to read ELF header\n", name);
phdr = (void*) (((unsigned char*)buf) + header->e_phoff);
if( ( header->e_ident[0] != 0x7f ) ||
( header->e_ident[1] != 'E' ) ||
( header->e_ident[2] != 'L' ) ||
( header->e_ident[3] != 'F' ) )
fatal_error( "%s: not an ELF binary... don't know how to load it\n", name );
if( header->e_machine != EM_386 )
fatal_error("%s: not an i386 ELF binary... don't know how to load it\n", name );
if (header->e_phnum > sizeof(loadcmds)/sizeof(loadcmds[0]))
fatal_error( "%s: oops... not enough space for load commands\n", name );
maplength = header->e_phnum * sizeof (ElfW(Phdr));
if (header->e_phoff + maplength > sizeof(buf))
fatal_error( "%s: oops... not enough space for ELF headers\n", name );
l->l_ld = 0;
l->l_addr = 0;
l->l_phdr = 0;
l->l_phnum = header->e_phnum;
l->l_entry = header->e_entry;
l->l_interp = 0;
for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
{
#ifdef DUMP_SEGMENTS
wld_printf( "ph = %x\n", ph );
wld_printf( " p_type = %x\n", ph->p_type );
wld_printf( " p_flags = %x\n", ph->p_flags );
wld_printf( " p_offset = %x\n", ph->p_offset );
wld_printf( " p_vaddr = %x\n", ph->p_vaddr );
wld_printf( " p_paddr = %x\n", ph->p_paddr );
wld_printf( " p_filesz = %x\n", ph->p_filesz );
wld_printf( " p_memsz = %x\n", ph->p_memsz );
wld_printf( " p_align = %x\n", ph->p_align );
#endif
switch (ph->p_type)
{
/* These entries tell us where to find things once the file's
segments are mapped in. We record the addresses it says
verbatim, and later correct for the run-time load address. */
case PT_DYNAMIC:
l->l_ld = (void *) ph->p_vaddr;
l->l_ldnum = ph->p_memsz / sizeof (Elf32_Dyn);
break;
case PT_PHDR:
l->l_phdr = (void *) ph->p_vaddr;
break;
case PT_LOAD:
{
if ((ph->p_align & page_mask) != 0)
fatal_error( "%s: ELF load command alignment not page-aligned\n", name );
if (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)
fatal_error( "%s: ELF load command address/offset not properly aligned\n", name );
c = &loadcmds[nloadcmds++];
c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
c->mapend = ((ph->p_vaddr + ph->p_filesz + page_mask) & ~page_mask);
c->dataend = ph->p_vaddr + ph->p_filesz;
c->allocend = ph->p_vaddr + ph->p_memsz;
c->mapoff = ph->p_offset & ~(ph->p_align - 1);
c->prot = 0;
if (ph->p_flags & PF_R)
c->prot |= PROT_READ;
if (ph->p_flags & PF_W)
c->prot |= PROT_WRITE;
if (ph->p_flags & PF_X)
c->prot |= PROT_EXEC;
}
break;
case PT_INTERP:
l->l_interp = ph->p_vaddr;
break;
case PT_TLS:
/*
* We don't need to set anything up because we're
* emulating the kernel, not ld-linux.so.2
* The ELF loader will set up the TLS data itself.
*/
case PT_SHLIB:
case PT_NOTE:
default:
break;
}
}
/* Now process the load commands and map segments into memory. */
c = loadcmds;
/* Length of the sections to be loaded. */
maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
if( header->e_type == ET_DYN )
{
ElfW(Addr) mappref;
mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
- MAP_BASE_ADDR (l));
/* Remember which part of the address space this object uses. */
l->l_map_start = (ElfW(Addr)) wld_mmap ((void *) mappref, maplength,
c->prot, MAP_COPY | MAP_FILE,
fd, c->mapoff);
/* wld_printf("set : offset = %x\n", c->mapoff); */
/* wld_printf("l->l_map_start = %x\n", l->l_map_start); */
l->l_map_end = l->l_map_start + maplength;
l->l_addr = l->l_map_start - c->mapstart;
wld_mprotect ((caddr_t) (l->l_addr + c->mapend),
loadcmds[nloadcmds - 1].allocend - c->mapend,
PROT_NONE);
goto postmap;
}
else
{
/* sanity check */
if ((char *)c->mapstart + maplength > preloader_start &&
(char *)c->mapstart <= preloader_end)
fatal_error( "%s: binary overlaps preloader (%x-%x)\n",
name, c->mapstart, (char *)c->mapstart + maplength );
ELF_FIXED_ADDRESS (loader, c->mapstart);
}
/* Remember which part of the address space this object uses. */
l->l_map_start = c->mapstart + l->l_addr;
l->l_map_end = l->l_map_start + maplength;
while (c < &loadcmds[nloadcmds])
{
if (c->mapend > c->mapstart)
/* Map the segment contents from the file. */
wld_mmap ((void *) (l->l_addr + c->mapstart),
c->mapend - c->mapstart, c->prot,
MAP_FIXED | MAP_COPY | MAP_FILE, fd, c->mapoff);
postmap:
if (l->l_phdr == 0
&& (ElfW(Off)) c->mapoff <= header->e_phoff
&& ((size_t) (c->mapend - c->mapstart + c->mapoff)
>= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
/* Found the program header in this segment. */
l->l_phdr = (void *)(unsigned int) (c->mapstart + header->e_phoff - c->mapoff);
if (c->allocend > c->dataend)
{
/* Extra zero pages should appear at the end of this segment,
after the data mapped from the file. */
ElfW(Addr) zero, zeroend, zeropage;
zero = l->l_addr + c->dataend;
zeroend = l->l_addr + c->allocend;
zeropage = (zero + page_mask) & ~page_mask;
/*
* This is different from the dl-load load...
* ld-linux.so.2 relies on the whole page being zero'ed
*/
zeroend = (zeroend + page_mask) & ~page_mask;
if (zeroend < zeropage)
{
/* All the extra data is in the last page of the segment.
We can just zero it. */
zeropage = zeroend;
}
if (zeropage > zero)
{
/* Zero the final part of the last page of the segment. */
if ((c->prot & PROT_WRITE) == 0)
{
/* Dag nab it. */
wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot|PROT_WRITE);
}
wld_memset ((void *) zero, '\0', zeropage - zero);
if ((c->prot & PROT_WRITE) == 0)
wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot);
}
if (zeroend > zeropage)
{
/* Map the remaining zero pages in from the zero fill FD. */
caddr_t mapat;
mapat = wld_mmap ((caddr_t) zeropage, zeroend - zeropage,
c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
-1, 0);
}
}
++c;
}
if (l->l_phdr == NULL) fatal_error("no program header\n");
l->l_phdr = (void *)((ElfW(Addr))l->l_phdr + l->l_addr);
l->l_entry += l->l_addr;
wld_close( fd );
}
static unsigned int elf_hash( const char *name )
{
unsigned int hi, hash = 0;
while (*name)
{
hash = (hash << 4) + (unsigned char)*name++;
hi = hash & 0xf0000000;
hash ^= hi;
hash ^= hi >> 24;
}
return hash;
}
static unsigned int gnu_hash( const char *name )
{
unsigned int h = 5381;
while (*name) h = h * 33 + (unsigned char)*name++;
return h;
}
/*
* Find a symbol in the symbol table of the executable loaded
*/
static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var, int type )
{
const ElfW(Dyn) *dyn = NULL;
const ElfW(Phdr) *ph;
const ElfW(Sym) *symtab = NULL;
const Elf_Symndx *hashtab = NULL;
const Elf32_Word *gnu_hashtab = NULL;
const char *strings = NULL;
Elf_Symndx idx;
/* check the values */
#ifdef DUMP_SYMS
wld_printf("%x %x\n", phdr, num );
#endif
if( ( phdr == NULL ) || ( num == 0 ) )
{
wld_printf("could not find PT_DYNAMIC header entry\n");
return NULL;
}
/* parse the (already loaded) ELF executable's header */
for (ph = phdr; ph < &phdr[num]; ++ph)
{
if( PT_DYNAMIC == ph->p_type )
{
dyn = (void *) ph->p_vaddr;
num = ph->p_memsz / sizeof (Elf32_Dyn);
break;
}
}
if( !dyn ) return NULL;
while( dyn->d_tag )
{
if( dyn->d_tag == DT_STRTAB )
strings = (const char*) dyn->d_un.d_ptr;
if( dyn->d_tag == DT_SYMTAB )
symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
if( dyn->d_tag == DT_HASH )
hashtab = (const Elf_Symndx *)dyn->d_un.d_ptr;
if( dyn->d_tag == DT_GNU_HASH )
gnu_hashtab = (const Elf32_Word *)dyn->d_un.d_ptr;
#ifdef DUMP_SYMS
wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
#endif
dyn++;
}
if( (!symtab) || (!strings) ) return NULL;
if (gnu_hashtab) /* new style hash table */
{
const unsigned int hash = gnu_hash(var);
const Elf32_Word nbuckets = gnu_hashtab[0];
const Elf32_Word symbias = gnu_hashtab[1];
const Elf32_Word nwords = gnu_hashtab[2];
const ElfW(Addr) *bitmask = (const ElfW(Addr) *)(gnu_hashtab + 4);
const Elf32_Word *buckets = (const Elf32_Word *)(bitmask + nwords);
const Elf32_Word *chains = buckets + nbuckets - symbias;
if (!(idx = buckets[hash % nbuckets])) return NULL;
do
{
if ((chains[idx] & ~1u) == (hash & ~1u) &&
symtab[idx].st_info == ELF32_ST_INFO( STB_GLOBAL, type ) &&
!wld_strcmp( strings + symtab[idx].st_name, var ))
goto found;
} while (!(chains[idx++] & 1u));
}
else if (hashtab) /* old style hash table */
{
const unsigned int hash = elf_hash(var);
const Elf_Symndx nbuckets = hashtab[0];
const Elf_Symndx *buckets = hashtab + 2;
const Elf_Symndx *chains = buckets + nbuckets;
for (idx = buckets[hash % nbuckets]; idx != STN_UNDEF; idx = chains[idx])
{
if (symtab[idx].st_info == ELF32_ST_INFO( STB_GLOBAL, type ) &&
!wld_strcmp( strings + symtab[idx].st_name, var ))
goto found;
}
}
return NULL;
found:
#ifdef DUMP_SYMS
wld_printf("Found %s -> %x\n", strings + symtab[idx].st_name, symtab[idx].st_value );
#endif
return (void *)symtab[idx].st_value;
}
/*
* preload_reserve
*
* Reserve a range specified in string format
*/
static void preload_reserve( const char *str )
{
const char *p;
unsigned long result = 0;
void *start = NULL, *end = NULL;
int first = 1;
for (p = str; *p; p++)
{
if (*p >= '0' && *p <= '9') result = result * 16 + *p - '0';
else if (*p >= 'a' && *p <= 'f') result = result * 16 + *p - 'a' + 10;
else if (*p >= 'A' && *p <= 'F') result = result * 16 + *p - 'A' + 10;
else if (*p == '-')
{
if (!first) goto error;
start = (void *)(result & ~page_mask);
result = 0;
first = 0;
}
else goto error;
}
if (!first) end = (void *)((result + page_mask) & ~page_mask);
else if (result) goto error; /* single value '0' is allowed */
/* sanity checks */
if (end <= start) start = end = NULL;
else if ((char *)end > preloader_start &&
(char *)start <= preloader_end)
{
wld_printf( "WINEPRELOADRESERVE range %x-%x overlaps preloader %x-%x\n",
start, end, preloader_start, preloader_end );
start = end = NULL;
}
/* check for overlap with low memory area */
if ((char *)end <= (char *)preload_info[0].addr + preload_info[0].size)
start = end = NULL;
else if ((char *)start < (char *)preload_info[0].addr + preload_info[0].size)
start = (char *)preload_info[0].addr + preload_info[0].size;
/* entry 2 is for the PE exe */
preload_info[2].addr = start;
preload_info[2].size = (char *)end - (char *)start;
return;
error:
fatal_error( "invalid WINEPRELOADRESERVE value '%s'\n", str );
}
/*
* is_in_preload_range
*
* Check if address of the given aux value is in one of the reserved ranges
*/
static int is_in_preload_range( const ElfW(auxv_t) *av, int type )
{
int i;
while (av->a_type != type && av->a_type != AT_NULL) av++;
if (av->a_type == type)
{
for (i = 0; preload_info[i].size; i++)
{
if ((char *)av->a_un.a_val >= (char *)preload_info[i].addr &&
(char *)av->a_un.a_val < (char *)preload_info[i].addr + preload_info[i].size)
return 1;
}
}
return 0;
}
/* set the process name if supported */
static void set_process_name( int argc, char *argv[] )
{
unsigned int i, off;
char *p, *name, *end;
/* set the process short name */
for (p = name = argv[1]; *p; p++) if (p[0] == '/' && p[1]) name = p + 1;
if (wld_prctl( 15 /* PR_SET_NAME */, (int)name ) == -1) return;
/* find the end of the argv array and move everything down */
end = argv[argc - 1];
while (*end) end++;
off = argv[1] - argv[0];
for (p = argv[1]; p <= end; p++) *(p - off) = *p;
wld_memset( end - off, 0, off );
for (i = 1; i < argc; i++) argv[i] -= off;
}
/*
* wld_start
*
* Repeat the actions the kernel would do when loading a dynamically linked .so
* Load the binary and then its ELF interpreter.
* Note, we assume that the binary is a dynamically linked ELF shared object.
*/
void* wld_start( void **stack )
{
int i, *pargc;
char **argv, **p;
char *interp, *reserve = NULL;
ElfW(auxv_t) new_av[12], delete_av[3], *av;
struct wld_link_map main_binary_map, ld_so_map;
struct wine_preload_info **wine_main_preload_info;
pargc = *stack;
argv = (char **)pargc + 1;
if (*pargc < 2) fatal_error( "Usage: %s wine_binary [args]\n", argv[0] );
/* skip over the parameters */
p = argv + *pargc + 1;
/* skip over the environment */
while (*p)
{
static const char res[] = "WINEPRELOADRESERVE=";
if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p + sizeof(res) - 1;
p++;
}
av = (ElfW(auxv_t)*) (p+1);
page_size = get_auxiliary( av, AT_PAGESZ, 4096 );
page_mask = page_size - 1;
preloader_start = (char *)_start - ((unsigned int)_start & page_mask);
preloader_end = (char *)((unsigned int)(_end + page_mask) & ~page_mask);
#ifdef DUMP_AUX_INFO
wld_printf( "stack = %x\n", *stack );
for( i = 0; i < *pargc; i++ ) wld_printf("argv[%x] = %s\n", i, argv[i]);
dump_auxiliary( av );
#endif
/* reserve memory that Wine needs */
if (reserve) preload_reserve( reserve );
for (i = 0; preload_info[i].size; i++)
wld_mmap( preload_info[i].addr, preload_info[i].size,
PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0 );
/* add an executable page at the top of the address space to defeat
* broken no-exec protections that play with the code selector limit */
wld_mprotect( (char *)0x80000000 - page_size, page_size, PROT_EXEC | PROT_READ );
/* load the main binary */
map_so_lib( argv[1], &main_binary_map );
/* load the ELF interpreter */
interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
map_so_lib( interp, &ld_so_map );
/* store pointer to the preload info into the appropriate main binary variable */
wine_main_preload_info = find_symbol( main_binary_map.l_phdr, main_binary_map.l_phnum,
"wine_main_preload_info", STT_OBJECT );
if (wine_main_preload_info) *wine_main_preload_info = preload_info;
else wld_printf( "wine_main_preload_info not found\n" );
#define SET_NEW_AV(n,type,val) new_av[n].a_type = (type); new_av[n].a_un.a_val = (val);
SET_NEW_AV( 0, AT_PHDR, (unsigned long)main_binary_map.l_phdr );
SET_NEW_AV( 1, AT_PHENT, sizeof(ElfW(Phdr)) );
SET_NEW_AV( 2, AT_PHNUM, main_binary_map.l_phnum );
SET_NEW_AV( 3, AT_PAGESZ, page_size );
SET_NEW_AV( 4, AT_BASE, ld_so_map.l_addr );
SET_NEW_AV( 5, AT_FLAGS, get_auxiliary( av, AT_FLAGS, 0 ) );
SET_NEW_AV( 6, AT_ENTRY, main_binary_map.l_entry );
SET_NEW_AV( 7, AT_UID, get_auxiliary( av, AT_UID, wld_getuid() ) );
SET_NEW_AV( 8, AT_EUID, get_auxiliary( av, AT_EUID, wld_geteuid() ) );
SET_NEW_AV( 9, AT_GID, get_auxiliary( av, AT_GID, wld_getgid() ) );
SET_NEW_AV(10, AT_EGID, get_auxiliary( av, AT_EGID, wld_getegid() ) );
SET_NEW_AV(11, AT_NULL, 0 );
#undef SET_NEW_AV
i = 0;
/* delete sysinfo values if addresses conflict */
if (is_in_preload_range( av, AT_SYSINFO )) delete_av[i++].a_type = AT_SYSINFO;
if (is_in_preload_range( av, AT_SYSINFO_EHDR )) delete_av[i++].a_type = AT_SYSINFO_EHDR;
delete_av[i].a_type = AT_NULL;
/* get rid of first argument */
set_process_name( *pargc, argv );
pargc[1] = pargc[0] - 1;
*stack = pargc + 1;
set_auxiliary_values( av, new_av, delete_av, stack );
#ifdef DUMP_AUX_INFO
wld_printf("new stack = %x\n", *stack);
wld_printf("jumping to %x\n", ld_so_map.l_entry);
#endif
return (void *)ld_so_map.l_entry;
}
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