glibc/include/link.h
Ulrich Drepper c0f62c5678 [BZ #77]
Update.
	Add support for namespaces in the dynamic linker.
	* dlfcn/Makefile (libdl-routines): Add dlmopen.
	* dlfcn/Versions [libdl, GLIBC_2.3.4]: Add dlmopen.
	* dlfcn/dlfcn.h: Define Lmid_t, LM_ID_BASE, and LM_ID_NEWLM.
	Declare dlmopen.  Document RTLD_DI_LMID.
	* dlfcn/dlinfo.c: Handle RTLD_DI_LMID.
	* dlfcn/dlmopen.c: New file.
	* dlfcn/dlopen.c: Pass new parameter to _dl_open.
	* dlfcn/dlopenold.c: Likewise.
	* elf/dl-addr.c: Adjust for removal of GL(dl_loaded).
	* elf/dl-caller.c: Likewise.
	* elf/dl-close.c: Likewise.
	* elf/dl-conflict.c: Likewise.
	* elf/dl-debug.c: Likewise.
	* elf/dl-lookup.c: Likewise.
	* elf/dl-sym.c: Likewise.
	* elf/dl-version.c: Likewise.
	* elf/do-lookup.h: Likewise.
	* elf/rtld.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/dl-librecon.h: Likewise.
	* elf/dl-depsc: Likewise.  Add new parameter to _dl_map_object.
	* elf/dl-fini.c: Call destructors in all namespaces.
	* elf/dl-iteratephdr.c: Compute total nloaded.  Adjust for removal of
	GL(dl_loaded).
	* elf/dl-libc.c: Pass new parameter to _dl_open.  Adjust for removal
	of GL(dl_loaded).
	* elf/dl-load.c (_dl_map_object_from_fd): Don't load ld.so a second
	time.  Reuse the one from the main namespace in all others.
	Pass new parameter to _dl_new_object.
	Adjust for removal of GL(dl_loaded).
	* elf/dl-object.c: Take new parameter.  Use it to initialize l_ns.
	Adjust for removal of GL(dl_loaded).
	* elf/dl-open.c (_dl_open): Take new parameter.
	Adjust for removal of GL(dl_loaded).
	* elf/dl-support.c: Replace global _dl_loaded etc variables with
	_dl_ns variable.
	* include/dlfcn.h: Adjust prototype of _dl_open.
	Define __LM_ID_CALLER.
	* include/link.h: Add l_real, l_ns, and l_direct_opencount elements.
	* sysdeps/generic/dl-tls.c: Bump TLS_STATIC_SURPLUS.  Since libc is
	using TLS we need memory appropriate to the number of namespaces.
	* sysdeps/generic/ldsodefs.h (struct rtld_global): Replace _dl_loaded,
	_dl_nloaded, _dl_global_scope, _dl_main_searchlist, and
	_dl_global_scope_alloc with _dl_ns element.  Define DL_NNS.
	Adjust prototypes of _dl_map_object and member in rtld_global_ro.
	* malloc/malloc.c: Include <dlfcn.h>.
	* malloc/arena.c (ptmalloc_init): If libc is not in primary namespace,
	never use brk.
	* elf/Makefile: Add rules to build and run tst-dlmopen1 and
	tst-dlmopen2.
	* elf/tst-dlmopen1.c: New file.
	* elf/tst-dlmopen1mod.c: New file.
	* elf/tst-dlmopen2.c: New file.

	* elf/dl-close.c: Improve reference counting by tracking direct loads.
	* elf/dl-lookup.c (add_dependency): Likewise.
	* elf/dl-open.c (dl_open_worker): Likewise.
	* elf/rtld.c (dl_main): Likewise.

2004-09-09  GOTO Masanori  <gotom@debian.or.jp>

	[BZ #77]
	* elf/dl-close.c: Count down l_opencount to check not only for
	l_reldeps, but also l_initfini.

2004-10-13  Ulrich Drepper  <drepper@redhat.com>
2004-10-14 02:08:23 +00:00

321 lines
11 KiB
C

/* Data structure for communication from the run-time dynamic linker for
loaded ELF shared objects.
Copyright (C) 1995-2002, 2003, 2004 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _LINK_H
#define _LINK_H 1
#include <elf.h>
#include <dlfcn.h>
#include <stddef.h>
#include <sys/types.h>
/* We use this macro to refer to ELF types independent of the native wordsize.
`ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
#define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type)
#define _ElfW(e,w,t) _ElfW_1 (e, w, _##t)
#define _ElfW_1(e,w,t) e##w##t
#include <bits/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */
#include <bits/link.h>
#include <dl-lookupcfg.h>
#include <tls.h> /* Defines USE_TLS. */
/* Rendezvous structure used by the run-time dynamic linker to communicate
details of shared object loading to the debugger. If the executable's
dynamic section has a DT_DEBUG element, the run-time linker sets that
element's value to the address where this structure can be found. */
struct r_debug
{
int r_version; /* Version number for this protocol. */
struct link_map *r_map; /* Head of the chain of loaded objects. */
/* This is the address of a function internal to the run-time linker,
that will always be called when the linker begins to map in a
library or unmap it, and again when the mapping change is complete.
The debugger can set a breakpoint at this address if it wants to
notice shared object mapping changes. */
ElfW(Addr) r_brk;
enum
{
/* This state value describes the mapping change taking place when
the `r_brk' address is called. */
RT_CONSISTENT, /* Mapping change is complete. */
RT_ADD, /* Beginning to add a new object. */
RT_DELETE /* Beginning to remove an object mapping. */
} r_state;
ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */
};
/* This is the instance of that structure used by the dynamic linker. */
extern struct r_debug _r_debug;
/* This symbol refers to the "dynamic structure" in the `.dynamic' section
of whatever module refers to `_DYNAMIC'. So, to find its own
`struct r_debug', a program could do:
for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)
if (dyn->d_tag == DT_DEBUG)
r_debug = (struct r_debug *) dyn->d_un.d_ptr;
*/
extern ElfW(Dyn) _DYNAMIC[];
/* 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; /* Base address shared object is loaded at. */
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;
/* Symbol hash table. */
Elf_Symndx l_nbuckets;
const Elf_Symndx *l_buckets, *l_chain;
unsigned int l_opencount; /* Counter for direct and indirect usage. */
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_used:1; /* Nonzero if the DSO is used. */
/* Array with version names. */
unsigned int l_nversions;
struct r_found_version *l_versions;
/* Collected information about own RPATH directories. */
struct r_search_path_struct l_rpath_dirs;
/* Collected results of relocation while profiling. */
ElfW(Addr) *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 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. */
dev_t l_dev;
ino64_t l_ino;
/* 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. */
unsigned int l_reldepsmax;
unsigned int l_reldepsact;
struct link_map **l_reldeps;
/* Various flag words. */
ElfW(Word) l_feature_1;
ElfW(Word) l_flags_1;
ElfW(Word) l_flags;
/* Temporarily used in `dl_close'. */
unsigned int l_idx;
struct link_map_machine l_mach;
struct
{
const ElfW(Sym) *sym;
int type_class;
#ifdef DL_LOOKUP_RETURNS_MAP
struct link_map *value;
#else
ElfW(Addr) value;
#endif
const ElfW(Sym) *ret;
} l_lookup_cache;
#ifdef USE_TLS
/* 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
/* 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;
#endif
/* Information used to change permission after the relocations are
done. */
ElfW(Addr) l_relro_addr;
size_t l_relro_size;
};
struct dl_phdr_info
{
ElfW(Addr) dlpi_addr;
const char *dlpi_name;
const ElfW(Phdr) *dlpi_phdr;
ElfW(Half) dlpi_phnum;
unsigned long long int dlpi_adds;
unsigned long long int dlpi_subs;
};
extern int dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
size_t size, void *data),
void *data);
extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
size_t size, void *data),
void *data);
#endif /* link.h */