mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 21:10:07 +00:00
142 lines
5.2 KiB
C
142 lines
5.2 KiB
C
/* Locating objects in the process image. ld.so implementation.
|
|
Copyright (C) 2021-2023 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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _DL_FIND_EH_FRAME_H
|
|
#define _DL_FIND_EH_FRAME_H
|
|
|
|
#include <assert.h>
|
|
#include <atomic.h>
|
|
#include <dlfcn.h>
|
|
#include <ldsodefs.h>
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
|
|
/* Internal version of struct dl_find_object. Does not include the
|
|
(yet unused) flags member. We need to make a copy of data also in
|
|
struct link_map to support non-contiguous mappings, and to support
|
|
software transactional memory (the link map is not covered by
|
|
transactions). */
|
|
struct dl_find_object_internal
|
|
{
|
|
uintptr_t map_start;
|
|
uintptr_t map_end; /* Set to map_start by dlclose. */
|
|
struct link_map *map; /* Set to NULL by dlclose. */
|
|
void *eh_frame;
|
|
#if DLFO_STRUCT_HAS_EH_DBASE
|
|
void *eh_dbase;
|
|
#endif
|
|
#if DLFO_STRUCT_HAS_EH_COUNT
|
|
int eh_count;
|
|
#endif
|
|
};
|
|
|
|
/* Create a copy of *SOURCE in *COPY using relaxed MO loads and
|
|
stores. */
|
|
static inline void
|
|
_dl_find_object_internal_copy (const struct dl_find_object_internal *source,
|
|
struct dl_find_object_internal *copy)
|
|
{
|
|
atomic_store_relaxed (©->map_start,
|
|
atomic_load_relaxed (&source->map_start));
|
|
atomic_store_relaxed (©->map_end,
|
|
atomic_load_relaxed (&source->map_end));
|
|
atomic_store_relaxed (©->map,
|
|
atomic_load_relaxed (&source->map));
|
|
atomic_store_relaxed (©->eh_frame,
|
|
atomic_load_relaxed (&source->eh_frame));
|
|
#if DLFO_STRUCT_HAS_EH_DBASE
|
|
atomic_store_relaxed (©->eh_dbase,
|
|
atomic_load_relaxed (&source->eh_dbase));
|
|
#endif
|
|
#if DLFO_STRUCT_HAS_EH_COUNT
|
|
atomic_store_relaxed (©->eh_count,
|
|
atomic_load_relaxed (&source->eh_count));
|
|
#endif
|
|
}
|
|
|
|
static inline void
|
|
_dl_find_object_to_external (struct dl_find_object_internal *internal,
|
|
struct dl_find_object *external)
|
|
{
|
|
external->dlfo_flags = 0;
|
|
external->dlfo_map_start = (void *) internal->map_start;
|
|
external->dlfo_map_end = (void *) internal->map_end;
|
|
external->dlfo_link_map = internal->map;
|
|
external->dlfo_eh_frame = internal->eh_frame;
|
|
# if DLFO_STRUCT_HAS_EH_DBASE
|
|
external->dlfo_eh_dbase = internal->eh_dbase;
|
|
# endif
|
|
# if DLFO_STRUCT_HAS_EH_COUNT
|
|
external->dlfo_eh_count = internal->eh_count;
|
|
# endif
|
|
}
|
|
|
|
/* Extract the object location data from a link map and writes it to
|
|
*RESULT using relaxed MO stores. */
|
|
static void __attribute__ ((unused))
|
|
_dl_find_object_from_map (struct link_map *l,
|
|
struct dl_find_object_internal *result)
|
|
{
|
|
atomic_store_relaxed (&result->map_start, (uintptr_t) l->l_map_start);
|
|
atomic_store_relaxed (&result->map_end, (uintptr_t) l->l_map_end);
|
|
atomic_store_relaxed (&result->map, l);
|
|
|
|
#if DLFO_STRUCT_HAS_EH_DBASE
|
|
atomic_store_relaxed (&result->eh_dbase, (void *) l->l_info[DT_PLTGOT]);
|
|
#endif
|
|
|
|
for (const ElfW(Phdr) *ph = l->l_phdr, *ph_end = l->l_phdr + l->l_phnum;
|
|
ph < ph_end; ++ph)
|
|
if (ph->p_type == DLFO_EH_SEGMENT_TYPE)
|
|
{
|
|
atomic_store_relaxed (&result->eh_frame,
|
|
(void *) (ph->p_vaddr + l->l_addr));
|
|
#if DLFO_STRUCT_HAS_EH_COUNT
|
|
atomic_store_relaxed (&result->eh_count, ph->p_memsz / 8);
|
|
#endif
|
|
return;
|
|
}
|
|
|
|
/* Object has no exception handling segment. */
|
|
atomic_store_relaxed (&result->eh_frame, NULL);
|
|
#if DLFO_STRUCT_HAS_EH_COUNT
|
|
atomic_store_relaxed (&result->eh_count, 0);
|
|
#endif
|
|
}
|
|
|
|
/* Called by the dynamic linker to set up the data structures for the
|
|
initially loaded objects. This creates a few persistent
|
|
allocations, so it should be called with the minimal malloc. */
|
|
void _dl_find_object_init (void) attribute_hidden;
|
|
|
|
/* Called by dlopen/dlmopen to add new objects to the DWARF EH frame
|
|
data structures. NEW_MAP is the dlopen'ed link map. Link maps on
|
|
the l_next list are added if l_object_processed is 0. Needs to
|
|
be protected by loader write lock. Returns true on success, false
|
|
on malloc failure. */
|
|
bool _dl_find_object_update (struct link_map *new_map) attribute_hidden;
|
|
|
|
/* Called by dlclose to remove the link map from the DWARF EH frame
|
|
data structures. Needs to be protected by loader write lock. */
|
|
void _dl_find_object_dlclose (struct link_map *l) attribute_hidden;
|
|
|
|
/* Called from __libc_freeres to deallocate malloc'ed memory. */
|
|
void _dl_find_object_freeres (void) attribute_hidden;
|
|
|
|
#endif /* _DL_FIND_OBJECT_H */
|