mirror of
https://sourceware.org/git/glibc.git
synced 2025-01-08 18:30:18 +00:00
421f82e5cc
* Makeconfig (+gccwarn): Add -Winline. * hurd/hurdsig.c (_hurd_internal_post_signal): If SS->context is set, avoid abort_rpcs, and use reply and intr ports saved in SS->context. * sysdeps/mach/hurd/i386/trampoline.c: Don't set SS->intr_port from SS->context. Don't clear SS->context. * sysdeps/mach/hurd/i386/sigreturn.c: Don't set SS->intr_port when setting SS->context. If msg_sig_post returns, re-lock and clear SS->context. Fri May 5 10:37:09 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu> * mach/Makefile (errsystems.c): Comment out generation rule. * sysdeps/mach/_strerror.c: Consider a system unknown if its bad_sub member is null. * mach/mig-alloc.c: Add weak alias to non-__ name.
92 lines
3.2 KiB
C
92 lines
3.2 KiB
C
/* On-demand PLT fixup for shared objects. i386 version.
|
|
Copyright (C) 1995 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 Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#include <link.h>
|
|
#include "dynamic-link.h"
|
|
|
|
/* This function is not called in the normal way. The PLT jumps here, not
|
|
using a call. The stack looks like this:
|
|
|
|
-->8(%esp) address to return to the caller of the function in the PLT
|
|
4(%esp) relocation offset for this PLT entry
|
|
0(%esp) identifier for this shared object (struct link_map *)
|
|
|
|
The user expects the real function the PLT refers to to be entered
|
|
with 8(%esp) as the top of stack. */
|
|
|
|
void
|
|
_dl_runtime_resolve (Elf32_Word reloc_offset)
|
|
{
|
|
__label__ return_insn;
|
|
struct link_map *l = (void *) &(&reloc_offset)[-1];
|
|
|
|
const Elf32_Sym *const symtab
|
|
= (const Elf32_Sym *) l->l_info[DT_SYMTAB]->d_un.d_ptr;
|
|
const char *strtab
|
|
= ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
|
|
|
|
const Elf32_Rel *const reloc = (void *) (l->l_info[DT_JMPREL]->d_un.d_ptr
|
|
+ reloc_offset);
|
|
|
|
const Elf32_Sym *definer;
|
|
Elf32_Addr loadbase;
|
|
struct link_map *scope, *real_next;
|
|
|
|
/* Look up the symbol's run-time value. */
|
|
|
|
real_next = l->l_next;
|
|
if (l->l_info[DT_SYMBOLIC])
|
|
{
|
|
l->l_prev->l_next = real_next;
|
|
l->l_next = _dl_loaded;
|
|
scope = l;
|
|
}
|
|
else
|
|
scope = _dl_loaded;
|
|
|
|
definer = &symtab[ELF32_R_SYM (reloc->r_info)];
|
|
loadbase = _dl_lookup_symbol (strtab + definer->st_name, &definer,
|
|
scope, l->l_name);
|
|
|
|
/* Restore list frobnication done above for DT_SYMBOLIC. */
|
|
l->l_next = real_next;
|
|
l->l_prev->l_next = l;
|
|
|
|
/* Apply the relocation with that value. */
|
|
elf_machine_rel (l, reloc, loadbase, definer);
|
|
|
|
/* The top of the stack is the word we set L from; but this location
|
|
holds the address we will return to. Store there the address of a
|
|
"ret" instruction, which will pop the stack and run the code at the
|
|
address in the next stack word. */
|
|
(&reloc_offset)[-1] = (Elf32_Word) &&return_insn;
|
|
|
|
/* The next stack word is our argument RELOC_OFFSET; but that "ret" will
|
|
pop and jump to this location, and the next stack word is the user's
|
|
return address. So store here the resolved address of the function
|
|
referred to by this PLT entry; once "ret" pops this address, the
|
|
function in the shared object will run with the stack arranged just as
|
|
when the user entered the PLT. */
|
|
(&reloc_offset)[0] = *(Elf32_Word *) reloc->r_offset;
|
|
|
|
return;
|
|
|
|
return_insn: asm volatile ("ret");
|
|
}
|