mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
41bdb6e20c
2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
388 lines
12 KiB
C
388 lines
12 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. i386 version.
|
|
Copyright (C) 1995,96,97,98,99,2000,2001 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C 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.
|
|
|
|
The GNU C 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 the GNU C Library; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#ifndef dl_machine_h
|
|
#define dl_machine_h
|
|
|
|
#define ELF_MACHINE_NAME "i386"
|
|
|
|
#include <sys/param.h>
|
|
|
|
/* Return nonzero iff ELF header is compatible with the running host. */
|
|
static inline int __attribute__ ((unused))
|
|
elf_machine_matches_host (const Elf32_Ehdr *ehdr)
|
|
{
|
|
return ehdr->e_machine == EM_386;
|
|
}
|
|
|
|
|
|
/* Return the link-time address of _DYNAMIC. Conveniently, this is the
|
|
first element of the GOT. This must be inlined in a function which
|
|
uses global data. */
|
|
static inline Elf32_Addr __attribute__ ((unused))
|
|
elf_machine_dynamic (void)
|
|
{
|
|
register Elf32_Addr *got asm ("%ebx");
|
|
return *got;
|
|
}
|
|
|
|
|
|
/* Return the run-time load address of the shared object. */
|
|
static inline Elf32_Addr __attribute__ ((unused))
|
|
elf_machine_load_address (void)
|
|
{
|
|
Elf32_Addr addr;
|
|
asm ("leal _dl_start@GOTOFF(%%ebx), %0\n"
|
|
"subl _dl_start@GOT(%%ebx), %0"
|
|
: "=r" (addr) : : "cc");
|
|
return addr;
|
|
}
|
|
|
|
#if !defined PROF && !__BOUNDED_POINTERS__
|
|
/* We add a declaration of this function here so that in dl-runtime.c
|
|
the ELF_MACHINE_RUNTIME_TRAMPOLINE macro really can pass the parameters
|
|
in registers.
|
|
|
|
We cannot use this scheme for profiling because the _mcount call
|
|
destroys the passed register information. */
|
|
/* GKM FIXME: Fix trampoline to pass bounds so we can do
|
|
without the `__unbounded' qualifier. */
|
|
static ElfW(Addr) fixup (struct link_map *__unbounded l, ElfW(Word) reloc_offset)
|
|
__attribute__ ((regparm (2), unused));
|
|
static ElfW(Addr) profile_fixup (struct link_map *l, ElfW(Word) reloc_offset,
|
|
ElfW(Addr) retaddr)
|
|
__attribute__ ((regparm (3), unused));
|
|
#endif
|
|
|
|
/* Set up the loaded object described by L so its unrelocated PLT
|
|
entries will jump to the on-demand fixup code in dl-runtime.c. */
|
|
|
|
static inline int __attribute__ ((unused))
|
|
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
|
|
{
|
|
Elf32_Addr *got;
|
|
extern void _dl_runtime_resolve (Elf32_Word);
|
|
extern void _dl_runtime_profile (Elf32_Word);
|
|
|
|
if (l->l_info[DT_JMPREL] && lazy)
|
|
{
|
|
/* The GOT entries for functions in the PLT have not yet been filled
|
|
in. Their initial contents will arrange when called to push an
|
|
offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
|
|
and then jump to _GLOBAL_OFFSET_TABLE[2]. */
|
|
got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
|
|
got[1] = (Elf32_Addr) l; /* Identify this shared object. */
|
|
|
|
/* The got[2] entry contains the address of a function which gets
|
|
called to get the address of a so far unresolved function and
|
|
jump to it. The profiling extension of the dynamic linker allows
|
|
to intercept the calls to collect information. In this case we
|
|
don't store the address in the GOT so that all future calls also
|
|
end in this function. */
|
|
if (__builtin_expect (profile, 0))
|
|
{
|
|
got[2] = (Elf32_Addr) &_dl_runtime_profile;
|
|
|
|
if (_dl_name_match_p (_dl_profile, l))
|
|
/* This is the object we are looking for. Say that we really
|
|
want profiling and the timers are started. */
|
|
_dl_profile_map = l;
|
|
}
|
|
else
|
|
/* This function will get called to fix up the GOT entry indicated by
|
|
the offset on the stack, and then jump to the resolved address. */
|
|
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
|
|
}
|
|
|
|
return lazy;
|
|
}
|
|
|
|
/* This code is used in dl-runtime.c to call the `fixup' function
|
|
and then redirect to the address it returns. */
|
|
#if !defined PROF && !__BOUNDED_POINTERS__
|
|
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
|
|
.text\n\
|
|
.globl _dl_runtime_resolve\n\
|
|
.type _dl_runtime_resolve, @function\n\
|
|
.align 16\n\
|
|
_dl_runtime_resolve:\n\
|
|
pushl %eax # Preserve registers otherwise clobbered.\n\
|
|
pushl %ecx\n\
|
|
pushl %edx\n\
|
|
movl 16(%esp), %edx # Copy args pushed by PLT in register. Note\n\
|
|
movl 12(%esp), %eax # that `fixup' takes its parameters in regs.\n\
|
|
call fixup # Call resolver.\n\
|
|
popl %edx # Get register content back.\n\
|
|
popl %ecx\n\
|
|
xchgl %eax, (%esp) # Get %eax contents end store function address.\n\
|
|
ret $8 # Jump to function address.\n\
|
|
.size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
|
|
\n\
|
|
.globl _dl_runtime_profile\n\
|
|
.type _dl_runtime_profile, @function\n\
|
|
.align 16\n\
|
|
_dl_runtime_profile:\n\
|
|
pushl %eax # Preserve registers otherwise clobbered.\n\
|
|
pushl %ecx\n\
|
|
pushl %edx\n\
|
|
movl 20(%esp), %ecx # Load return address\n\
|
|
movl 16(%esp), %edx # Copy args pushed by PLT in register. Note\n\
|
|
movl 12(%esp), %eax # that `fixup' takes its parameters in regs.\n\
|
|
call profile_fixup # Call resolver.\n\
|
|
popl %edx # Get register content back.\n\
|
|
popl %ecx\n\
|
|
xchgl %eax, (%esp) # Get %eax contents end store function address.\n\
|
|
ret $8 # Jump to function address.\n\
|
|
.size _dl_runtime_profile, .-_dl_runtime_profile\n\
|
|
.previous\n\
|
|
");
|
|
#else
|
|
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\n\
|
|
.text\n\
|
|
.globl _dl_runtime_resolve\n\
|
|
.globl _dl_runtime_profile\n\
|
|
.type _dl_runtime_resolve, @function\n\
|
|
.type _dl_runtime_profile, @function\n\
|
|
.align 16\n\
|
|
_dl_runtime_resolve:\n\
|
|
_dl_runtime_profile:\n\
|
|
pushl %eax # Preserve registers otherwise clobbered.\n\
|
|
pushl %ecx\n\
|
|
pushl %edx\n\
|
|
movl 16(%esp), %edx # Push the arguments for `fixup'\n\
|
|
movl 12(%esp), %eax\n\
|
|
pushl %edx\n\
|
|
pushl %eax\n\
|
|
call fixup # Call resolver.\n\
|
|
popl %edx # Pop the parameters\n\
|
|
popl %ecx\n\
|
|
popl %edx # Get register content back.\n\
|
|
popl %ecx\n\
|
|
xchgl %eax, (%esp) # Get %eax contents end store function address.\n\
|
|
ret $8 # Jump to function address.\n\
|
|
.size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
|
|
.size _dl_runtime_profile, .-_dl_runtime_profile\n\
|
|
.previous\n\
|
|
");
|
|
#endif
|
|
|
|
/* Mask identifying addresses reserved for the user program,
|
|
where the dynamic linker should not map anything. */
|
|
#define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
|
|
|
|
/* Initial entry point code for the dynamic linker.
|
|
The C function `_dl_start' is the real entry point;
|
|
its return value is the user program's entry point. */
|
|
|
|
#define RTLD_START asm ("\n\
|
|
.text\n\
|
|
.align 16\n\
|
|
0: movl (%esp), %ebx\n\
|
|
ret\n\
|
|
.align 16\n\
|
|
.globl _start\n\
|
|
.globl _dl_start_user\n\
|
|
_start:\n\
|
|
pushl %esp\n\
|
|
call _dl_start\n\
|
|
popl %ebx\n\
|
|
_dl_start_user:\n\
|
|
# Save the user entry point address in %edi.\n\
|
|
movl %eax, %edi\n\
|
|
# Point %ebx at the GOT.\n\
|
|
call 0b\n\
|
|
addl $_GLOBAL_OFFSET_TABLE_, %ebx\n\
|
|
# Store the highest stack address\n\
|
|
movl __libc_stack_end@GOT(%ebx), %eax\n\
|
|
movl %esp, (%eax)\n\
|
|
# See if we were run as a command with the executable file\n\
|
|
# name as an extra leading argument.\n\
|
|
movl _dl_skip_args@GOT(%ebx), %eax\n\
|
|
movl (%eax), %eax\n\
|
|
# Pop the original argument count.\n\
|
|
popl %edx\n\
|
|
# Adjust the stack pointer to skip _dl_skip_args words.\n\
|
|
leal (%esp,%eax,4), %esp\n\
|
|
# Subtract _dl_skip_args from argc.\n\
|
|
subl %eax, %edx\n\
|
|
# Push argc back on the stack.\n\
|
|
push %edx\n\
|
|
# The special initializer gets called with the stack just\n\
|
|
# as the application's entry point will see it; it can\n\
|
|
# switch stacks if it moves these contents over.\n\
|
|
" RTLD_START_SPECIAL_INIT "\n\
|
|
# Load the parameters again.\n\
|
|
# (eax, edx, ecx, *--esp) = (_dl_loaded, argc, argv, envp)\n\
|
|
movl _dl_loaded@GOT(%ebx), %esi\n\
|
|
leal 8(%esp,%edx,4), %eax\n\
|
|
leal 4(%esp), %ecx\n\
|
|
pushl %eax\n\
|
|
movl (%esi), %eax\n\
|
|
# Call the function to run the initializers.\n\
|
|
call _dl_init@PLT\n\
|
|
# Pass our finalizer function to the user in %edx, as per ELF ABI.\n\
|
|
movl _dl_fini@GOT(%ebx), %edx\n\
|
|
# Jump to the user's entry point.\n\
|
|
jmp *%edi\n\
|
|
.previous\n\
|
|
");
|
|
|
|
#ifndef RTLD_START_SPECIAL_INIT
|
|
#define RTLD_START_SPECIAL_INIT /* nothing */
|
|
#endif
|
|
|
|
/* Nonzero iff TYPE should not be allowed to resolve to one of
|
|
the main executable's symbols, as for a COPY reloc. */
|
|
#define elf_machine_lookup_noexec_p(type) ((type) == R_386_COPY)
|
|
|
|
/* Nonzero iff TYPE describes relocation of a PLT entry, so
|
|
PLT entries should not be allowed to define the value. */
|
|
#define elf_machine_lookup_noplt_p(type) ((type) == R_386_JMP_SLOT)
|
|
|
|
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
|
|
#define ELF_MACHINE_JMP_SLOT R_386_JMP_SLOT
|
|
|
|
/* The i386 never uses Elf32_Rela relocations. */
|
|
#define ELF_MACHINE_NO_RELA 1
|
|
|
|
/* We define an initialization functions. This is called very early in
|
|
_dl_sysdep_start. */
|
|
#define DL_PLATFORM_INIT dl_platform_init ()
|
|
|
|
extern const char *_dl_platform;
|
|
|
|
static inline void __attribute__ ((unused))
|
|
dl_platform_init (void)
|
|
{
|
|
if (_dl_platform != NULL && *_dl_platform == '\0')
|
|
/* Avoid an empty string which would disturb us. */
|
|
_dl_platform = NULL;
|
|
}
|
|
|
|
static inline Elf32_Addr
|
|
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
|
|
const Elf32_Rel *reloc,
|
|
Elf32_Addr *reloc_addr, Elf32_Addr value)
|
|
{
|
|
return *reloc_addr = value;
|
|
}
|
|
|
|
/* Return the final value of a plt relocation. */
|
|
static inline Elf32_Addr
|
|
elf_machine_plt_value (struct link_map *map, const Elf32_Rel *reloc,
|
|
Elf32_Addr value)
|
|
{
|
|
return value;
|
|
}
|
|
|
|
#endif /* !dl_machine_h */
|
|
|
|
#ifdef RESOLVE
|
|
|
|
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
|
|
MAP is the object containing the reloc. */
|
|
|
|
static inline void
|
|
elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
|
|
const Elf32_Sym *sym, const struct r_found_version *version,
|
|
Elf32_Addr *const reloc_addr)
|
|
{
|
|
if (ELF32_R_TYPE (reloc->r_info) == R_386_RELATIVE)
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
/* This is defined in rtld.c, but nowhere in the static libc.a;
|
|
make the reference weak so static programs can still link.
|
|
This declaration cannot be done when compiling rtld.c
|
|
(i.e. #ifdef RTLD_BOOTSTRAP) because rtld.c contains the
|
|
common defn for _dl_rtld_map, which is incompatible with a
|
|
weak decl in the same file. */
|
|
weak_extern (_dl_rtld_map);
|
|
if (map != &_dl_rtld_map) /* Already done in rtld itself. */
|
|
#endif
|
|
*reloc_addr += map->l_addr;
|
|
}
|
|
else if (ELF32_R_TYPE (reloc->r_info) != R_386_NONE)
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
const Elf32_Sym *const refsym = sym;
|
|
#endif
|
|
Elf32_Addr value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
|
|
if (sym)
|
|
value += sym->st_value;
|
|
|
|
switch (ELF32_R_TYPE (reloc->r_info))
|
|
{
|
|
case R_386_GLOB_DAT:
|
|
case R_386_JMP_SLOT:
|
|
*reloc_addr = value;
|
|
break;
|
|
#ifndef RTLD_BOOTSTRAP
|
|
case R_386_32:
|
|
*reloc_addr += value;
|
|
break;
|
|
case R_386_PC32:
|
|
*reloc_addr += (value - (Elf32_Addr) reloc_addr);
|
|
break;
|
|
case R_386_COPY:
|
|
if (sym == NULL)
|
|
/* This can happen in trace mode if an object could not be
|
|
found. */
|
|
break;
|
|
if (__builtin_expect (sym->st_size > refsym->st_size, 0)
|
|
|| (__builtin_expect (sym->st_size < refsym->st_size, 0)
|
|
&& __builtin_expect (_dl_verbose, 0)))
|
|
{
|
|
const char *strtab;
|
|
|
|
strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
|
|
_dl_error_printf ("\
|
|
%s: Symbol `%s' has different size in shared object, consider re-linking\n",
|
|
_dl_argv[0] ?: "<program name unknown>",
|
|
strtab + refsym->st_name);
|
|
}
|
|
memcpy (reloc_addr, (void *) value, MIN (sym->st_size,
|
|
refsym->st_size));
|
|
break;
|
|
#endif
|
|
#if !defined RTLD_BOOTSTRAP || defined _NDEBUG
|
|
default:
|
|
/* We add these checks in the version to relocate ld.so only
|
|
if we are still debugging. */
|
|
_dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 0);
|
|
break;
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
elf_machine_lazy_rel (struct link_map *map,
|
|
Elf32_Addr l_addr, const Elf32_Rel *reloc)
|
|
{
|
|
Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
|
|
/* Check for unexpected PLT reloc type. */
|
|
if (__builtin_expect (ELF32_R_TYPE (reloc->r_info), R_386_JMP_SLOT)
|
|
== R_386_JMP_SLOT)
|
|
*reloc_addr += l_addr;
|
|
else
|
|
_dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 1);
|
|
}
|
|
|
|
#endif /* RESOLVE */
|