/* Data structure for communication from the run-time dynamic linker for
loaded ELF shared objects.
Copyright (C) 1995-2018 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
<http://www.gnu.org/licenses/>. */
#ifndef _PRIVATE_LINK_H
#define _PRIVATE_LINK_H 1
#ifdef _LINK_H
# error this should be impossible
#endif
# ifndef _ISOMAC
/* Get most of the contents from the public header, but we define a
different `struct link_map' type for private use. The la_objopen
prototype uses the type, so we have to declare it separately. */
# define link_map link_map_public
# define la_objopen la_objopen_wrongproto
# endif
#include <elf/link.h>
# ifndef _ISOMAC
#undef link_map
#undef la_objopen
struct link_map;
extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid,
uintptr_t *__cookie);
#include <stdint.h>
#include <stddef.h>
#include <linkmap.h>
#include <dl-fileid.h>
#include <dl-lookupcfg.h>
#include <tls.h>
#include <libc-lock.h>
/* Some internal data structures of the dynamic linker used in the
linker map. We only provide forward declarations. */
struct libname_list;
struct r_found_version;
struct r_search_path_elem;
/* Forward declaration. */
struct link_map;
/* Structure to describe a single list of scope elements. The lookup
functions get passed an array of pointers to such structures. */
struct r_scope_elem
{
/* Array of maps for the scope. */
struct link_map **r_list;
/* Number of entries in the scope. */
unsigned int r_nlist;
};
/* Structure to record search path and allocation mechanism. */
struct r_search_path_struct
{
struct r_search_path_elem **dirs;
int malloced;
};
/* Structure describing a loaded shared object. The `l_next' and `l_prev'
members form a chain of all the shared objects loaded at startup.
These data structures exist in space used by the run-time dynamic linker;
modifying them may have disastrous results.
This data structure might change in future, if necessary. User-level
programs must avoid defining objects of this type. */
struct link_map
{
/* These first few members are part of the protocol with the debugger.
This is the same format used in SVR4. */
ElfW(Addr) l_addr; /* Difference between the address in the ELF
file and the addresses in memory. */
char *l_name; /* Absolute file name object was found in. */
ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
/* All following members are internal to the dynamic linker.
They may change without notice. */
/* This is an element which is only ever different from a pointer to
the very same copy of this type for ld.so when it is used in more
than one namespace. */
struct link_map *l_real;
/* Number of the namespace this link map belongs to. */
Lmid_t l_ns;
struct libname_list *l_libname;
/* Indexed pointers to dynamic section.
[0,DT_NUM) are indexed by the processor-independent tags.
[DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
[DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM) are
indexed by DT_VERSIONTAGIDX(tagvalue).
[DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM) are indexed by
DT_EXTRATAGIDX(tagvalue).
[DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM,
DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM) are
indexed by DT_VALTAGIDX(tagvalue) and
[DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM,
DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM+DT_ADDRNUM)
are indexed by DT_ADDRTAGIDX(tagvalue), see <elf.h>. */
ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
+ DT_EXTRANUM + DT_VALNUM + DT_ADDRNUM];
const ElfW(Phdr) *l_phdr; /* Pointer to program header table in core. */
ElfW(Addr) l_entry; /* Entry point location. */
ElfW(Half) l_phnum; /* Number of program header entries. */
ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */
/* Array of DT_NEEDED dependencies and their dependencies, in
dependency order for symbol lookup (with and without
duplicates). There is no entry before the dependencies have
been loaded. */
struct r_scope_elem l_searchlist;
/* We need a special searchlist to process objects marked with
DT_SYMBOLIC. */
struct r_scope_elem l_symbolic_searchlist;
/* Dependent object that first caused this object to be loaded. */
struct link_map *l_loader;
/* Array with version names. */
struct r_found_version *l_versions;
unsigned int l_nversions;
/* Symbol hash table. */
Elf_Symndx l_nbuckets;
Elf32_Word l_gnu_bitmask_idxbits;
Elf32_Word l_gnu_shift;
const ElfW(Addr) *l_gnu_bitmask;
union
{
const Elf32_Word *l_gnu_buckets;
const Elf_Symndx *l_chain;
};
union
{
const Elf32_Word *l_gnu_chain_zero;
const Elf_Symndx *l_buckets;
};
unsigned int l_direct_opencount; /* Reference count for dlopen/dlclose. */
enum /* Where this object came from. */
{
lt_executable, /* The main executable program. */
lt_library, /* Library needed by main executable. */
lt_loaded /* Extra run-time loaded shared object. */
} l_type:2;
unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */
unsigned int l_reserved:2; /* Reserved for internal use. */
unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
to by `l_phdr' is allocated. */
unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
the l_libname list. */
unsigned int l_faked:1; /* Nonzero if this is a faked descriptor
without associated file. */
unsigned int l_need_tls_init:1; /* Nonzero if GL(dl_init_static_tls)
should be called on this link map
when relocation finishes. */
unsigned int l_auditing:1; /* Nonzero if the DSO is used in auditing. */
unsigned int l_audit_any_plt:1; /* Nonzero if at least one audit module
is interested in the PLT interception.*/
unsigned int l_removed:1; /* Nozero if the object cannot be used anymore
since it is removed. */
unsigned int l_contiguous:1; /* Nonzero if inter-segment holes are
mprotected or if no holes are present at
all. */
unsigned int l_symbolic_in_local_scope:1; /* Nonzero if l_local_scope
during LD_TRACE_PRELINKING=1
contains any DT_SYMBOLIC
libraries. */
unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be
freed, ie. not allocated with
the dummy malloc in ld.so. */
#include <link_map.h>
/* Collected information about own RPATH directories. */
struct r_search_path_struct l_rpath_dirs;
/* Collected results of relocation while profiling. */
struct reloc_result
{
DL_FIXUP_VALUE_TYPE addr;
struct link_map *bound;
unsigned int boundndx;
uint32_t enterexit;
unsigned int flags;
} *l_reloc_result;
/* Pointer to the version information if available. */
ElfW(Versym) *l_versyms;
/* String specifying the path where this object was found. */
const char *l_origin;
/* Start and finish of memory map for this object. l_map_start
need not be the same as l_addr. */
ElfW(Addr) l_map_start, l_map_end;
/* End of the executable part of the mapping. */
ElfW(Addr) l_text_end;
/* Default array for 'l_scope'. */
struct r_scope_elem *l_scope_mem[4];
/* Size of array allocated for 'l_scope'. */
size_t l_scope_max;
/* This is an array defining the lookup scope for this link map.
There are initially at most three different scope lists. */
struct r_scope_elem **l_scope;
/* A similar array, this time only with the local scope. This is
used occasionally. */
struct r_scope_elem *l_local_scope[2];
/* This information is kept to check for sure whether a shared
object is the same as one already loaded. */
struct r_file_id l_file_id;
/* Collected information about own RUNPATH directories. */
struct r_search_path_struct l_runpath_dirs;
/* List of object in order of the init and fini calls. */
struct link_map **l_initfini;
/* List of the dependencies introduced through symbol binding. */
struct link_map_reldeps
{
unsigned int act;
struct link_map *list[];
} *l_reldeps;
unsigned int l_reldepsmax;
/* Nonzero if the DSO is used. */
unsigned int l_used;
/* Various flag words. */
ElfW(Word) l_feature_1;
ElfW(Word) l_flags_1;
ElfW(Word) l_flags;
/* Temporarily used in `dl_close'. */
int l_idx;
struct link_map_machine l_mach;
struct
{
const ElfW(Sym) *sym;
int type_class;
struct link_map *value;
const ElfW(Sym) *ret;
} l_lookup_cache;
/* Thread-local storage related info. */
/* Start of the initialization image. */
void *l_tls_initimage;
/* Size of the initialization image. */
size_t l_tls_initimage_size;
/* Size of the TLS block. */
size_t l_tls_blocksize;
/* Alignment requirement of the TLS block. */
size_t l_tls_align;
/* Offset of first byte module alignment. */
size_t l_tls_firstbyte_offset;
#ifndef NO_TLS_OFFSET
# define NO_TLS_OFFSET 0
#endif
#ifndef FORCED_DYNAMIC_TLS_OFFSET
# if NO_TLS_OFFSET == 0
# define FORCED_DYNAMIC_TLS_OFFSET -1
# elif NO_TLS_OFFSET == -1
# define FORCED_DYNAMIC_TLS_OFFSET -2
# else
# error "FORCED_DYNAMIC_TLS_OFFSET is not defined"
# endif
#endif
/* For objects present at startup time: offset in the static TLS block. */
ptrdiff_t l_tls_offset;
/* Index of the module in the dtv array. */
size_t l_tls_modid;
/* Number of thread_local objects constructed by this DSO. This is
atomically accessed and modified and is not always protected by the load
lock. See also: CONCURRENCY NOTES in cxa_thread_atexit_impl.c. */
size_t l_tls_dtor_count;
/* Information used to change permission after the relocations are
done. */
ElfW(Addr) l_relro_addr;
size_t l_relro_size;
unsigned long long int l_serial;
/* Audit information. This array apparent must be the last in the
structure. Never add something after it. */
struct auditstate
{
uintptr_t cookie;
unsigned int bindflags;
} l_audit[0];
};
#if __ELF_NATIVE_CLASS == 32
# define symbind symbind32
#elif __ELF_NATIVE_CLASS == 64
# define symbind symbind64
#else
# error "__ELF_NATIVE_CLASS must be defined"
#endif
extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
size_t size, void *data),
void *data);
hidden_proto (__dl_iterate_phdr)
/* We use this macro to refer to ELF macros independent of the native
wordsize. `ELFW(R_TYPE)' is used in place of `ELF32_R_TYPE' or
`ELF64_R_TYPE'. */
#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
# endif /* !_ISOMAC */
#endif /* include/link.h */