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elf: Fix dynamic-link.h usage on rtld.c

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The 4af6982e4c fix does not fully handle RTLD_BOOTSTRAP usage on
rtld.c due two issues:

  1. RTLD_BOOTSTRAP is also used on dl-machine.h on various
     architectures and it changes the semantics of various machine
     relocation functions.

  2. The elf_get_dynamic_info() change was done sideways, previously
     to 490e6c62aa get-dynamic-info.h was included by the first
     dynamic-link.h include *without* RTLD_BOOTSTRAP being defined.
     It means that the code within elf_get_dynamic_info() that uses
     RTLD_BOOTSTRAP is in fact unused.

To fix 1. this patch now includes dynamic-link.h only once with
RTLD_BOOTSTRAP defined.  The ELF_DYNAMIC_RELOCATE call will now have
the relocation fnctions with the expected semantics for the loader.

And to fix 2. part of 4af6982e4c is reverted (the check argument
elf_get_dynamic_info() is not required) and the RTLD_BOOTSTRAP
pieces are removed.

To reorganize the includes the static TLS definition is moved to
its own header to avoid a circular dependency (it is defined on
dynamic-link.h and dl-machine.h requires it at same time other
dynamic-link.h definition requires dl-machine.h defitions).

Also ELF_MACHINE_NO_REL, ELF_MACHINE_NO_RELA, and ELF_MACHINE_PLT_REL
are moved to its own header.  Only ancient ABIs need special values
(arm, i386, and mips), so a generic one is used as default.

The powerpc Elf64_FuncDesc is also moved to its own header, since
csu code required its definition (which would require either include
elf/ folder or add a full path with elf/).

Checked on x86_64, i686, aarch64, armhf, powerpc64, powerpc32,
and powerpc64le.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
This commit is contained in:
Adhemerval Zanella
2021-10-13 09:49:34 -03:00
parent e59ced2384
commit d6d89608ac
36 changed files with 272 additions and 175 deletions
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25
elf/get-dynamic-info.h
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@@ -22,10 +22,11 @@
#define _GET_DYNAMIC_INFO_H
#include <assert.h>
#include <dl-machine-rel.h>
#include <libc-diag.h>
static inline void __attribute__ ((unused, always_inline))
elf_get_dynamic_info (struct link_map *l, bool check)
elf_get_dynamic_info (struct link_map *l)
{
#if __ELF_NATIVE_CLASS == 32
typedef Elf32_Word d_tag_utype;
@@ -33,7 +34,7 @@ elf_get_dynamic_info (struct link_map *l, bool check)
typedef Elf64_Xword d_tag_utype;
#endif
#if !defined RTLD_BOOTSTRAP && !defined STATIC_PIE_BOOTSTRAP
#ifndef STATIC_PIE_BOOTSTRAP
if (l->l_ld == NULL)
return;
#endif
@@ -111,21 +112,10 @@ elf_get_dynamic_info (struct link_map *l, bool check)
if (info[DT_REL] != NULL)
assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
#endif
#ifdef RTLD_BOOTSTRAP
if (check)
{
/* Only the bind now flags are allowed. */
assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
|| (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
/* Flags must not be set for ld.so. */
assert (info[DT_FLAGS] == NULL
|| (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
# ifdef STATIC_PIE_BOOTSTRAP
assert (info[DT_RUNPATH] == NULL);
assert (info[DT_RPATH] == NULL);
# endif
}
#else
#ifdef STATIC_PIE_BOOTSTRAP
assert (info[DT_RUNPATH] == NULL);
assert (info[DT_RPATH] == NULL);
#endif
if (info[DT_FLAGS] != NULL)
{
/* Flags are used. Translate to the old form where available.
@@ -163,7 +153,6 @@ elf_get_dynamic_info (struct link_map *l, bool check)
if (info[DT_RUNPATH] != NULL)
/* If both RUNPATH and RPATH are given, the latter is ignored. */
info[DT_RPATH] = NULL;
#endif
}
#endif