[glibc] elf: Move _dl_rtld_map, _dl_rtld_audit_state out of GL
Florian Weimer
fw@sourceware.org
Fri Dec 20 15:15:23 GMT 2024
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ef5823d955dd7e6b4ffed9f3a8455d131cd7a737
commit ef5823d955dd7e6b4ffed9f3a8455d131cd7a737
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Dec 20 15:52:57 2024 +0100
elf: Move _dl_rtld_map, _dl_rtld_audit_state out of GL
This avoids immediate GLIBC_PRIVATE ABI issues if the size of
struct link_map or struct auditstate changes.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diff:
---
elf/dl-load.c | 10 ++--
elf/rtld.c | 131 +++++++++++++++++++++++----------------------
elf/setup-vdso.h | 4 +-
sysdeps/generic/ldsodefs.h | 19 ++++---
4 files changed, 82 insertions(+), 82 deletions(-)
diff --git a/elf/dl-load.c b/elf/dl-load.c
index e986d7faab..4b8bd8a498 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -755,7 +755,7 @@ _dl_init_paths (const char *llp, const char *source,
l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
#ifdef SHARED
if (l == NULL)
- l = &GL (dl_rtld_map);
+ l = &_dl_rtld_map;
#endif
assert (l->l_type != lt_loaded);
@@ -979,8 +979,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
/* When loading into a namespace other than the base one we must
avoid loading ld.so since there can only be one copy. Ever. */
if (__glibc_unlikely (nsid != LM_ID_BASE)
- && (_dl_file_id_match_p (&id, &GL(dl_rtld_map).l_file_id)
- || _dl_name_match_p (name, &GL(dl_rtld_map))))
+ && (_dl_file_id_match_p (&id, &_dl_rtld_map.l_file_id)
+ || _dl_name_match_p (name, &_dl_rtld_map)))
{
/* This is indeed ld.so. Create a new link_map which refers to
the real one for almost everything. */
@@ -989,7 +989,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
goto fail_new;
/* Refer to the real descriptor. */
- l->l_real = &GL(dl_rtld_map);
+ l->l_real = &_dl_rtld_map;
/* Copy l_addr and l_ld to avoid a GDB warning with dlmopen(). */
l->l_addr = l->l_real->l_addr;
@@ -2044,7 +2044,7 @@ _dl_map_object (struct link_map *loader, const char *name,
l = (loader
?: GL(dl_ns)[LM_ID_BASE]._ns_loaded
# ifdef SHARED
- ?: &GL(dl_rtld_map)
+ ?: &_dl_rtld_map
# endif
);
diff --git a/elf/rtld.c b/elf/rtld.c
index 44bcf29ff6..0637c53017 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -380,6 +380,8 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
extern struct rtld_global_ro _rtld_local_ro
__attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
+struct link_map _dl_rtld_map;
+struct auditstate _dl_rtld_auditstate[DL_NNS];
static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv);
@@ -466,22 +468,21 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
/* Transfer data about ourselves to the permanent link_map structure. */
#ifndef DONT_USE_BOOTSTRAP_MAP
- GL(dl_rtld_map).l_addr = info->l.l_addr;
- GL(dl_rtld_map).l_ld = info->l.l_ld;
- GL(dl_rtld_map).l_ld_readonly = info->l.l_ld_readonly;
- memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
- sizeof GL(dl_rtld_map).l_info);
- GL(dl_rtld_map).l_mach = info->l.l_mach;
- GL(dl_rtld_map).l_relocated = 1;
+ _dl_rtld_map.l_addr = info->l.l_addr;
+ _dl_rtld_map.l_ld = info->l.l_ld;
+ _dl_rtld_map.l_ld_readonly = info->l.l_ld_readonly;
+ memcpy (_dl_rtld_map.l_info, info->l.l_info, sizeof _dl_rtld_map.l_info);
+ _dl_rtld_map.l_mach = info->l.l_mach;
+ _dl_rtld_map.l_relocated = 1;
#endif
- _dl_setup_hash (&GL(dl_rtld_map));
- GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
- GL(dl_rtld_map).l_map_start = (ElfW(Addr)) &__ehdr_start;
- GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
+ _dl_setup_hash (&_dl_rtld_map);
+ _dl_rtld_map.l_real = &_dl_rtld_map;
+ _dl_rtld_map.l_map_start = (ElfW(Addr)) &__ehdr_start;
+ _dl_rtld_map.l_map_end = (ElfW(Addr)) _end;
/* Copy the TLS related data if necessary. */
#ifndef DONT_USE_BOOTSTRAP_MAP
# if NO_TLS_OFFSET != 0
- GL(dl_rtld_map).l_tls_offset = NO_TLS_OFFSET;
+ _dl_rtld_map.l_tls_offset = NO_TLS_OFFSET;
# endif
#endif
@@ -508,7 +509,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
}
#ifdef DONT_USE_BOOTSTRAP_MAP
-# define bootstrap_map GL(dl_rtld_map)
+# define bootstrap_map _dl_rtld_map
#else
# define bootstrap_map info.l
#endif
@@ -1035,8 +1036,8 @@ ERROR: audit interface '%s' requires version %d (maximum supported version %d);
/* The dynamic linker link map is statically allocated, so the
cookie in _dl_new_object has not happened. */
- link_map_audit_state (&GL (dl_rtld_map), GLRO (dl_naudit))->cookie
- = (intptr_t) &GL (dl_rtld_map);
+ link_map_audit_state (&_dl_rtld_map, GLRO (dl_naudit))->cookie
+ = (intptr_t) &_dl_rtld_map;
++GLRO(dl_naudit);
@@ -1063,7 +1064,7 @@ load_audit_modules (struct link_map *main_map, struct audit_list *audit_list)
if (GLRO(dl_naudit) > 0)
{
_dl_audit_objopen (main_map, LM_ID_BASE);
- _dl_audit_objopen (&GL(dl_rtld_map), LM_ID_BASE);
+ _dl_audit_objopen (&_dl_rtld_map, LM_ID_BASE);
}
}
@@ -1074,8 +1075,8 @@ rtld_chain_load (struct link_map *main_map, char *argv0)
{
/* The dynamic loader run against itself. */
const char *rtld_soname
- = ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
- + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val);
+ = ((const char *) D_PTR (&_dl_rtld_map, l_info[DT_STRTAB])
+ + _dl_rtld_map.l_info[DT_SONAME]->d_un.d_val);
if (main_map->l_info[DT_SONAME] != NULL
&& strcmp (rtld_soname,
((const char *) D_PTR (main_map, l_info[DT_STRTAB])
@@ -1164,7 +1165,7 @@ rtld_setup_main_map (struct link_map *main_map)
_dl_rtld_libname.name = ((const char *) main_map->l_addr
+ ph->p_vaddr);
/* _dl_rtld_libname.next = NULL; Already zero. */
- GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
+ _dl_rtld_map.l_libname = &_dl_rtld_libname;
has_interp = true;
break;
@@ -1246,16 +1247,16 @@ rtld_setup_main_map (struct link_map *main_map)
= (char *) main_map->l_tls_initimage + main_map->l_addr;
if (! main_map->l_map_end)
main_map->l_map_end = ~0;
- if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
+ if (! _dl_rtld_map.l_libname && _dl_rtld_map.l_name)
{
/* We were invoked directly, so the program might not have a
PT_INTERP. */
- _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
+ _dl_rtld_libname.name = _dl_rtld_map.l_name;
/* _dl_rtld_libname.next = NULL; Already zero. */
- GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
+ _dl_rtld_map.l_libname = &_dl_rtld_libname;
}
else
- assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
+ assert (_dl_rtld_map.l_libname); /* How else did we get here? */
return has_interp;
}
@@ -1373,7 +1374,7 @@ dl_main (const ElfW(Phdr) *phdr,
char **orig_argv = _dl_argv;
/* Note the place where the dynamic linker actually came from. */
- GL(dl_rtld_map).l_name = rtld_progname;
+ _dl_rtld_map.l_name = rtld_progname;
while (_dl_argc > 1)
if (! strcmp (_dl_argv[1], "--list"))
@@ -1652,23 +1653,23 @@ dl_main (const ElfW(Phdr) *phdr,
/* If the current libname is different from the SONAME, add the
latter as well. */
- if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
- && strcmp (GL(dl_rtld_map).l_libname->name,
- (const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
- + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val) != 0)
+ if (_dl_rtld_map.l_info[DT_SONAME] != NULL
+ && strcmp (_dl_rtld_map.l_libname->name,
+ (const char *) D_PTR (&_dl_rtld_map, l_info[DT_STRTAB])
+ + _dl_rtld_map.l_info[DT_SONAME]->d_un.d_val) != 0)
{
static struct libname_list newname;
- newname.name = ((char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
- + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_ptr);
+ newname.name = ((char *) D_PTR (&_dl_rtld_map, l_info[DT_STRTAB])
+ + _dl_rtld_map.l_info[DT_SONAME]->d_un.d_ptr);
newname.next = NULL;
newname.dont_free = 1;
- assert (GL(dl_rtld_map).l_libname->next == NULL);
- GL(dl_rtld_map).l_libname->next = &newname;
+ assert (_dl_rtld_map.l_libname->next == NULL);
+ _dl_rtld_map.l_libname->next = &newname;
}
/* The ld.so must be relocated since otherwise loading audit modules
will fail since they reuse the very same ld.so. */
- assert (GL(dl_rtld_map).l_relocated);
+ assert (_dl_rtld_map.l_relocated);
if (! rtld_is_main)
{
@@ -1700,7 +1701,7 @@ dl_main (const ElfW(Phdr) *phdr,
_exit (has_interp ? 0 : 2);
}
- struct link_map **first_preload = &GL(dl_rtld_map).l_next;
+ struct link_map **first_preload = &_dl_rtld_map.l_next;
/* Set up the data structures for the system-supplied DSO early,
so they can influence _dl_init_paths. */
setup_vdso (main_map, &first_preload);
@@ -1713,20 +1714,20 @@ dl_main (const ElfW(Phdr) *phdr,
call_init_paths (&state);
/* Initialize _r_debug_extended. */
- struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
+ struct r_debug *r = _dl_debug_initialize (_dl_rtld_map.l_addr,
LM_ID_BASE);
r->r_state = RT_CONSISTENT;
/* Put the link_map for ourselves on the chain so it can be found by
name. Note that at this point the global chain of link maps contains
exactly one element, which is pointed to by dl_loaded. */
- if (! GL(dl_rtld_map).l_name)
+ if (! _dl_rtld_map.l_name)
/* If not invoked directly, the dynamic linker shared object file was
found by the PT_INTERP name. */
- GL(dl_rtld_map).l_name = (char *) GL(dl_rtld_map).l_libname->name;
- GL(dl_rtld_map).l_type = lt_library;
- main_map->l_next = &GL(dl_rtld_map);
- GL(dl_rtld_map).l_prev = main_map;
+ _dl_rtld_map.l_name = (char *) _dl_rtld_map.l_libname->name;
+ _dl_rtld_map.l_type = lt_library;
+ main_map->l_next = &_dl_rtld_map;
+ _dl_rtld_map.l_prev = main_map;
++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
++GL(dl_load_adds);
@@ -1744,8 +1745,8 @@ dl_main (const ElfW(Phdr) *phdr,
const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff;
- GL(dl_rtld_map).l_phdr = rtld_phdr;
- GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
+ _dl_rtld_map.l_phdr = rtld_phdr;
+ _dl_rtld_map.l_phnum = rtld_ehdr->e_phnum;
/* PT_GNU_RELRO is usually the last phdr. */
@@ -1753,15 +1754,15 @@ dl_main (const ElfW(Phdr) *phdr,
while (cnt-- > 0)
if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
{
- GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
- GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
+ _dl_rtld_map.l_relro_addr = rtld_phdr[cnt].p_vaddr;
+ _dl_rtld_map.l_relro_size = rtld_phdr[cnt].p_memsz;
break;
}
/* Add the dynamic linker to the TLS list if it also uses TLS. */
- if (GL(dl_rtld_map).l_tls_blocksize != 0)
+ if (_dl_rtld_map.l_tls_blocksize != 0)
/* Assign a module ID. Do this before loading any audit modules. */
- _dl_assign_tls_modid (&GL(dl_rtld_map));
+ _dl_assign_tls_modid (&_dl_rtld_map);
audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_AUDIT);
audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_DEPAUDIT);
@@ -1955,9 +1956,9 @@ dl_main (const ElfW(Phdr) *phdr,
main_map->l_searchlist.r_list[--i]->l_global = 1;
/* Remove _dl_rtld_map from the chain. */
- GL(dl_rtld_map).l_prev->l_next = GL(dl_rtld_map).l_next;
- if (GL(dl_rtld_map).l_next != NULL)
- GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
+ _dl_rtld_map.l_prev->l_next = _dl_rtld_map.l_next;
+ if (_dl_rtld_map.l_next != NULL)
+ _dl_rtld_map.l_next->l_prev = _dl_rtld_map.l_prev;
for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
if (is_rtld_link_map (main_map->l_searchlist.r_list[i]))
@@ -1967,17 +1968,17 @@ dl_main (const ElfW(Phdr) *phdr,
symbol search order because gdb uses the chain's order as its
symbol search order. */
- GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
+ _dl_rtld_map.l_prev = main_map->l_searchlist.r_list[i - 1];
if (__glibc_likely (state.mode == rtld_mode_normal))
{
- GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
+ _dl_rtld_map.l_next = (i + 1 < main_map->l_searchlist.r_nlist
? main_map->l_searchlist.r_list[i + 1]
: NULL);
#ifdef NEED_DL_SYSINFO_DSO
if (GLRO(dl_sysinfo_map) != NULL
- && GL(dl_rtld_map).l_prev->l_next == GLRO(dl_sysinfo_map)
- && GL(dl_rtld_map).l_next != GLRO(dl_sysinfo_map))
- GL(dl_rtld_map).l_prev = GLRO(dl_sysinfo_map);
+ && _dl_rtld_map.l_prev->l_next == GLRO(dl_sysinfo_map)
+ && _dl_rtld_map.l_next != GLRO(dl_sysinfo_map))
+ _dl_rtld_map.l_prev = GLRO(dl_sysinfo_map);
#endif
}
else
@@ -1986,14 +1987,14 @@ dl_main (const ElfW(Phdr) *phdr,
In this case it doesn't matter much where we put the
interpreter object, so we just initialize the list pointer so
that the assertion below holds. */
- GL(dl_rtld_map).l_next = GL(dl_rtld_map).l_prev->l_next;
+ _dl_rtld_map.l_next = _dl_rtld_map.l_prev->l_next;
- assert (GL(dl_rtld_map).l_prev->l_next == GL(dl_rtld_map).l_next);
- GL(dl_rtld_map).l_prev->l_next = &GL(dl_rtld_map);
- if (GL(dl_rtld_map).l_next != NULL)
+ assert (_dl_rtld_map.l_prev->l_next == _dl_rtld_map.l_next);
+ _dl_rtld_map.l_prev->l_next = &_dl_rtld_map;
+ if (_dl_rtld_map.l_next != NULL)
{
- assert (GL(dl_rtld_map).l_next->l_prev == GL(dl_rtld_map).l_prev);
- GL(dl_rtld_map).l_next->l_prev = &GL(dl_rtld_map);
+ assert (_dl_rtld_map.l_next->l_prev == _dl_rtld_map.l_prev);
+ _dl_rtld_map.l_next->l_prev = &_dl_rtld_map;
}
/* Now let us see whether all libraries are available in the
@@ -2135,7 +2136,7 @@ dl_main (const ElfW(Phdr) *phdr,
while (i-- > 0)
{
struct link_map *l = main_map->l_initfini[i];
- if (l != &GL(dl_rtld_map) && ! l->l_faked)
+ if (l != &_dl_rtld_map && ! l->l_faked)
{
args.l = l;
_dl_receive_error (print_unresolved, relocate_doit,
@@ -2284,7 +2285,7 @@ dl_main (const ElfW(Phdr) *phdr,
/* Also allocated with the fake malloc(). */
l->l_free_initfini = 0;
- if (l != &GL(dl_rtld_map))
+ if (l != &_dl_rtld_map)
_dl_relocate_object (l, l->l_scope, GLRO(dl_lazy) ? RTLD_LAZY : 0,
consider_profiling);
@@ -2333,15 +2334,15 @@ dl_main (const ElfW(Phdr) *phdr,
RTLD_TIMING_VAR (start);
rtld_timer_start (&start);
- _dl_relocate_object_no_relro (&GL(dl_rtld_map), main_map->l_scope, 0, 0);
+ _dl_relocate_object_no_relro (&_dl_rtld_map, main_map->l_scope, 0, 0);
/* The malloc implementation has been relocated, so resolving
its symbols (and potentially calling IFUNC resolvers) is safe
at this point. */
__rtld_malloc_init_real (main_map);
- if (GL(dl_rtld_map).l_relro_size != 0)
- _dl_protect_relro (&GL(dl_rtld_map));
+ if (_dl_rtld_map.l_relro_size != 0)
+ _dl_protect_relro (&_dl_rtld_map);
rtld_timer_accum (&relocate_time, start);
}
diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
index 888e1e4897..2efdc19ff9 100644
--- a/elf/setup-vdso.h
+++ b/elf/setup-vdso.h
@@ -91,8 +91,8 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
/* Rearrange the list so this DSO appears after rtld_map. */
assert (l->l_next == NULL);
assert (l->l_prev == main_map);
- GL(dl_rtld_map).l_next = l;
- l->l_prev = &GL(dl_rtld_map);
+ _dl_rtld_map.l_next = l;
+ l->l_prev = &_dl_rtld_map;
*first_preload = &l->l_next;
# else
GL(dl_nns) = 1;
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 2c25c8db46..cec56e2214 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -392,14 +392,6 @@ struct rtld_global
/* List of search directories. */
EXTERN struct r_search_path_elem *_dl_all_dirs;
- /* Structure describing the dynamic linker itself. */
- EXTERN struct link_map _dl_rtld_map;
-#ifdef SHARED
- /* Used to store the audit information for the link map of the
- dynamic loader. */
- struct auditstate _dl_rtld_auditstate[DL_NNS];
-#endif
-
/* Get architecture specific definitions. */
#define PROCINFO_DECL
#ifndef PROCINFO_CLASS
@@ -1323,11 +1315,18 @@ rtld_active (void)
return GLRO(dl_init_all_dirs) != NULL;
}
+/* Pre-allocated link map for the dynamic linker itself. */
+extern struct link_map _dl_rtld_map attribute_hidden;
+
+/* Used to store the audit information for the link map of the
+ dynamic loader. */
+extern struct auditstate _dl_rtld_auditstate[DL_NNS] attribute_hidden;
+
/* 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);
+ return l == &_dl_rtld_map;
}
static inline struct auditstate *
@@ -1335,7 +1334,7 @@ link_map_audit_state (struct link_map *l, size_t index)
{
if (is_rtld_link_map (l))
/* The auditstate array is stored separately. */
- return &GL (dl_rtld_auditstate) [index];
+ return _dl_rtld_auditstate + index;
else
{
/* The auditstate array follows the link map in memory. */
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