[PATCH v2 1/2] elf: Introduce is_rtld_link_map
Florian Weimer
fweimer@redhat.com
Tue Dec 17 12:51:02 GMT 2024
Unconditionally define it to false for static builds.
This avoids the awkward use of weak_extern for _dl_rtld_map
in checks that cannot be possibly true on static builds.
---
v2: Remove dependency on second patch.
elf/dl-dst.h | 7 +------
elf/do-rel.h | 11 +----------
elf/dynamic-link.h | 2 +-
elf/rtld.c | 2 +-
sysdeps/arm/dl-machine.h | 11 +----------
sysdeps/generic/ldsodefs.h | 16 +++++++++++++++-
sysdeps/mips/dl-machine.h | 16 +++-------------
sysdeps/powerpc/powerpc64/dl-machine.h | 4 ++--
sysdeps/sh/dl-machine.h | 13 ++-----------
sysdeps/x86/dl-prop.h | 2 +-
10 files changed, 28 insertions(+), 56 deletions(-)
diff --git a/elf/dl-dst.h b/elf/dl-dst.h
index 07100e5ff9..bff3685b83 100644
--- a/elf/dl-dst.h
+++ b/elf/dl-dst.h
@@ -18,11 +18,6 @@
#include "trusted-dirs.h"
-#ifdef SHARED
-# define IS_RTLD(l) (l) == &GL(dl_rtld_map)
-#else
-# define IS_RTLD(l) 0
-#endif
/* Guess from the number of DSTs the length of the result string. */
#define DL_DST_REQUIRED(l, name, len, cnt) \
({ \
@@ -44,7 +39,7 @@
auditing, in ld.so. */ \
if ((l)->l_origin == NULL) \
{ \
- assert ((l)->l_name[0] == '\0' || IS_RTLD (l)); \
+ assert ((l)->l_name[0] == '\0' || is_rtld_link_map (l)); \
(l)->l_origin = _dl_get_origin (); \
dst_len = ((l)->l_origin && (l)->l_origin != (char *) -1 \
? strlen ((l)->l_origin) : 0); \
diff --git a/elf/do-rel.h b/elf/do-rel.h
index afea61cfd2..f9841966d5 100644
--- a/elf/do-rel.h
+++ b/elf/do-rel.h
@@ -102,16 +102,7 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
else
#endif
{
- /* 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. */
-# ifndef SHARED
- weak_extern (GL(dl_rtld_map));
-# endif
- if (map != &GL(dl_rtld_map)) /* Already done in rtld itself. */
+ if (!is_rtld_link_map (map)) /* Already done in rtld itself. */
# if !defined DO_RELA || defined ELF_MACHINE_REL_RELATIVE
/* Rela platforms get the offset from r_addend and this must
be copied in the relocation address. Therefore we can skip
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 370b0e872e..7649ea89e5 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -192,7 +192,7 @@ elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
do { \
int edr_lazy = elf_machine_runtime_setup ((map), (scope), (lazy), \
(consider_profile)); \
- if (((map) != &GL(dl_rtld_map) || DO_RTLD_BOOTSTRAP)) \
+ if (!is_rtld_link_map (map) || DO_RTLD_BOOTSTRAP) \
ELF_DYNAMIC_DO_RELR (map); \
ELF_DYNAMIC_DO_REL ((map), (scope), edr_lazy, skip_ifunc); \
ELF_DYNAMIC_DO_RELA ((map), (scope), edr_lazy, skip_ifunc); \
diff --git a/elf/rtld.c b/elf/rtld.c
index b8cc3f605f..44bcf29ff6 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1960,7 +1960,7 @@ dl_main (const ElfW(Phdr) *phdr,
GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
- if (main_map->l_searchlist.r_list[i] == &GL(dl_rtld_map))
+ if (is_rtld_link_map (main_map->l_searchlist.r_list[i]))
break;
/* Insert the link map for the dynamic loader into the chain in
diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h
index 9186831be3..b328287a18 100644
--- a/sysdeps/arm/dl-machine.h
+++ b/sysdeps/arm/dl-machine.h
@@ -351,16 +351,7 @@ elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
{
ElfW(Addr) tmp;
# 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. */
-# ifndef SHARED
- weak_extern (_dl_rtld_map);
-# endif
- if (map == &GL(dl_rtld_map))
+ if (is_rtld_link_map (map))
/* Undo the relocation done here during bootstrapping.
Now we will relocate it anew, possibly using a
binding found in the user program or a loaded library
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 91447a5e77..84724ac37b 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1329,10 +1329,17 @@ rtld_active (void)
return GLRO(dl_init_all_dirs) != NULL;
}
+/* Returns true of L is the link map of the dynamic linker itself. */
+static inline bool
+is_rtld_link_map (const struct link_map *l)
+{
+ return l == &GL(dl_rtld_map);
+}
+
static inline struct auditstate *
link_map_audit_state (struct link_map *l, size_t index)
{
- if (l == &GL (dl_rtld_map))
+ if (is_rtld_link_map (l))
/* The auditstate array is stored separately. */
return &GL (dl_rtld_auditstate) [index];
else
@@ -1395,6 +1402,13 @@ void DL_ARCH_FIXUP_ATTRIBUTE _dl_audit_pltexit (struct link_map *l,
attribute_hidden;
#else /* !SHARED */
+/* No special dynamic linker link map in static builds. */
+static inline bool
+is_rtld_link_map (const struct link_map *l)
+{
+ return false;
+}
+
static inline void
_dl_audit_objclose (struct link_map *l)
{
diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h
index 10e30f1e90..7a361edd4d 100644
--- a/sysdeps/mips/dl-machine.h
+++ b/sysdeps/mips/dl-machine.h
@@ -436,16 +436,6 @@ elf_machine_reloc (struct link_map *map, struct r_scope_elem *scope[],
const unsigned long int r_type = ELFW(R_TYPE) (r_info);
ElfW(Addr) *addr_field = (ElfW(Addr) *) reloc_addr;
-#if !defined RTLD_BOOTSTRAP && !defined SHARED
- /* 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 (GL(dl_rtld_map));
-#endif
-
switch (r_type)
{
#if !defined (RTLD_BOOTSTRAP)
@@ -534,7 +524,7 @@ elf_machine_reloc (struct link_map *map, struct r_scope_elem *scope[],
though it's not ABI compliant. Some day we should
bite the bullet and stop doing this. */
#ifndef RTLD_BOOTSTRAP
- if (map != &GL(dl_rtld_map))
+ if (!is_rtld_link_map (map))
#endif
reloc_value += SYMBOL_ADDRESS (map, sym, true);
}
@@ -553,7 +543,7 @@ elf_machine_reloc (struct link_map *map, struct r_scope_elem *scope[],
}
else
#ifndef RTLD_BOOTSTRAP
- if (map != &GL(dl_rtld_map))
+ if (!is_rtld_link_map (map))
#endif
reloc_value += map->l_addr;
@@ -749,7 +739,7 @@ elf_machine_got_rel (struct link_map *map, struct r_scope_elem *scope[], int laz
n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
/* The dynamic linker's local got entries have already been relocated. */
- if (map != &GL(dl_rtld_map))
+ if (!is_rtld_link_map (map))
{
/* got[0] is reserved. got[1] is also reserved for the dynamic object
generated by gnu ld. Skip these reserved entries from relocation. */
diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h
index 2b6f5d2b08..5855393b2b 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.h
+++ b/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -537,7 +537,7 @@ elf_machine_fixup_plt (struct link_map *map, lookup_t sym_map,
if (finaladdr != 0 && map != sym_map && !sym_map->l_relocated
#if !defined RTLD_BOOTSTRAP && defined SHARED
/* Bootstrap map doesn't have l_relocated set for it. */
- && sym_map != &GL(dl_rtld_map)
+ && !is_rtld_link_map (sym_map)
#endif
)
offset = sym_map->l_addr;
@@ -662,7 +662,7 @@ resolve_ifunc (Elf64_Addr value,
if (map != sym_map
# if !defined RTLD_BOOTSTRAP && defined SHARED
/* Bootstrap map doesn't have l_relocated set for it. */
- && sym_map != &GL(dl_rtld_map)
+ && !is_rtld_link_map (map)
# endif
&& !sym_map->l_relocated)
{
diff --git a/sysdeps/sh/dl-machine.h b/sysdeps/sh/dl-machine.h
index c2c970d0c4..01cd5114c4 100644
--- a/sysdeps/sh/dl-machine.h
+++ b/sysdeps/sh/dl-machine.h
@@ -284,7 +284,7 @@ elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
if (__glibc_unlikely (r_type == R_SH_RELATIVE))
{
#ifndef RTLD_BOOTSTRAP
- if (map != &GL(dl_rtld_map)) /* Already done in rtld itself. */
+ if (is_rtld_link_map (map)) /* Already done in rtld itself. */
#endif
{
if (reloc->r_addend)
@@ -380,16 +380,7 @@ elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
case R_SH_DIR32:
{
#if !defined 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. */
-# ifndef SHARED
- weak_extern (_dl_rtld_map);
-# endif
- if (map == &GL(dl_rtld_map))
+ if (is_rtld_link_map (map))
/* Undo the relocation done here during bootstrapping.
Now we will relocate it anew, possibly using a
binding found in the user program or a loaded library
diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
index 08387dfaff..62619d7dbe 100644
--- a/sysdeps/x86/dl-prop.h
+++ b/sysdeps/x86/dl-prop.h
@@ -46,7 +46,7 @@ dl_isa_level_check (struct link_map *m, const char *program)
#ifdef SHARED
/* Skip ISA level check for ld.so since ld.so won't run if its ISA
level is higher than CPU. */
- if (l == &GL(dl_rtld_map) || l->l_real == &GL(dl_rtld_map))
+ if (is_rtld_link_map (l) || is_rtld_link_map (l->l_real))
continue;
#endif
base-commit: 87cd94bba4091d22e24116298ade33b712ada235
prerequisite-patch-id: c9ba33bbc4825db275743eb86611ff8f09629acc
prerequisite-patch-id: b7d52ec947792319fae789c7167a5b53f5cecc07
prerequisite-patch-id: 58340abac5aa1f27f2049ac48e09fc50277bce18
--
2.47.1
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