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authorRoland McGrath <roland@gnu.org>1996-02-13 07:05:16 +0000
committerRoland McGrath <roland@gnu.org>1996-02-13 07:05:16 +0000
commit38334018ff9ea088c24afd6c2a5b3baa12b6110e (patch)
treee9f7d34d82c062e2140e8affd34c8c2e70f7fd28 /sysdeps
parentdbdb6189d5d66b165b4b502498572cbe7e78874e (diff)
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Tue Feb 13 00:12:12 1996 Roland McGrath <roland@charlie-brown.gnu.ai.mit.edu>
* sysdeps/i386/dl-machine.h (ELF_MACHINE_RUNTIME_TRAMPOLINE, elf_machine_relplt): New macros. * elf/dl-runtime.c: New file. * sysdeps/i386/dl-runtime.c, sysdeps/stub/dl-runtime.c: Files removed. * sysdeps/i386/dl-machine.h (ELF_MACHINE_RUNTIME_TRAMPOLINE, elf_machine_relplt): New macros. * elf/dl-runtime.c: New file. * sysdeps/i386/dl-runtime.c, sysdeps/stub/dl-runtime.c: Files removed.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/i386/dl-machine.h14
-rw-r--r--sysdeps/i386/dl-runtime.c94
-rw-r--r--sysdeps/stub/dl-runtime.c64
3 files changed, 13 insertions, 159 deletions
diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 4ce4d4b..8f72073 100644
--- a/sysdeps/i386/dl-machine.h
+++ b/sysdeps/i386/dl-machine.h
@@ -157,8 +157,20 @@ elf_machine_runtime_setup (struct link_map *l, int lazy)
the offset on the stack, and then jump to the resolved address. */
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
}
-}
+ /* This code is used in dl-runtime.c to call the `fixup' function
+ and then redirect to the address it returns. */
+#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
+ .globl _dl_runtime_resolve
+ .type _dl_runtime_resolve, @function
+_dl_runtime_resolve:
+ call fixup # Args pushed by PLT.
+ addl $8, %esp # Pop args.
+ jmp *%eax # Jump to function address.
+");
+/* The PLT uses Elf32_Rel relocs. */
+#define elf_machine_relplt elf_machine_rel
+}
/* Mask identifying addresses reserved for the user program,
where the dynamic linker should not map anything. */
diff --git a/sysdeps/i386/dl-runtime.c b/sysdeps/i386/dl-runtime.c
deleted file mode 100644
index 5e4a289..0000000
--- a/sysdeps/i386/dl-runtime.c
+++ /dev/null
@@ -1,94 +0,0 @@
-/* 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_addr + l->l_info[DT_SYMTAB]->d_un.d_ptr);
- const char *strtab =
- (const char *) (l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
-
- const Elf32_Rel *const reloc
- = (const void *) (l->l_addr + 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_next = _dl_loaded;
- if (l->l_prev)
- l->l_prev->l_next = real_next;
- 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, 0);
-
- /* Restore list frobnication done above for DT_SYMBOLIC. */
- l->l_next = real_next;
- if (l->l_prev)
- 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 *) (l->l_addr + reloc->r_offset);
-
- return;
-
- return_insn: asm volatile ("ret");
-}
diff --git a/sysdeps/stub/dl-runtime.c b/sysdeps/stub/dl-runtime.c
deleted file mode 100644
index f660ef2..0000000
--- a/sysdeps/stub/dl-runtime.c
+++ /dev/null
@@ -1,64 +0,0 @@
-/* On-demand PLT fixup for shared objects. Stub 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. */
-void
-_dl_runtime_resolve ()
-{
- struct link_map *l = ???;
- Elf32_Word reloc_offset = ???;
-
- 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);
-
- /* 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->l_addr, l->l_info, reloc, loadbase, definer);
-}