[BZ #2766]
[glibc.git] / include / link.h
blob3079ae873955051d9be9144e616f50eac842d8a2
1 /* Data structure for communication from the run-time dynamic linker for
2 loaded ELF shared objects.
3 Copyright (C) 1995-2002,2003,2004,2005,2006 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #ifndef _PRIVATE_LINK_H
22 #define _PRIVATE_LINK_H 1
24 #ifdef _LINK_H
25 # error this should be impossible
26 #endif
28 /* Get most of the contents from the public header, but we define a
29 different `struct link_map' type for private use. The la_objopen
30 prototype uses the type, so we have to declare it separately. */
31 #define link_map link_map_public
32 #define la_objopen la_objopen_wrongproto
33 #include <elf/link.h>
34 #undef link_map
35 #undef la_objopen
37 struct link_map;
38 extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid,
39 uintptr_t *__cookie);
42 #include <stddef.h>
43 #include <bits/linkmap.h>
44 #include <dl-lookupcfg.h>
45 #include <tls.h> /* Defines USE_TLS. */
48 /* Some internal data structures of the dynamic linker used in the
49 linker map. We only provide forward declarations. */
50 struct libname_list;
51 struct r_found_version;
52 struct r_search_path_elem;
54 /* Forward declaration. */
55 struct link_map;
57 /* Structure to describe a single list of scope elements. The lookup
58 functions get passed an array of pointers to such structures. */
59 struct r_scope_elem
61 /* Array of maps for the scope. */
62 struct link_map **r_list;
63 /* Number of entries in the scope. */
64 unsigned int r_nlist;
68 /* Structure to record search path and allocation mechanism. */
69 struct r_search_path_struct
71 struct r_search_path_elem **dirs;
72 int malloced;
76 /* Structure describing a loaded shared object. The `l_next' and `l_prev'
77 members form a chain of all the shared objects loaded at startup.
79 These data structures exist in space used by the run-time dynamic linker;
80 modifying them may have disastrous results.
82 This data structure might change in future, if necessary. User-level
83 programs must avoid defining objects of this type. */
85 struct link_map
87 /* These first few members are part of the protocol with the debugger.
88 This is the same format used in SVR4. */
90 ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
91 char *l_name; /* Absolute file name object was found in. */
92 ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
93 struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
95 /* All following members are internal to the dynamic linker.
96 They may change without notice. */
98 /* This is an element which is only ever different from a pointer to
99 the very same copy of this type for ld.so when it is used in more
100 than one namespace. */
101 struct link_map *l_real;
103 /* Number of the namespace this link map belongs to. */
104 Lmid_t l_ns;
106 struct libname_list *l_libname;
107 /* Indexed pointers to dynamic section.
108 [0,DT_NUM) are indexed by the processor-independent tags.
109 [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
110 [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM) are
111 indexed by DT_VERSIONTAGIDX(tagvalue).
112 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
113 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM) are indexed by
114 DT_EXTRATAGIDX(tagvalue).
115 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM,
116 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM) are
117 indexed by DT_VALTAGIDX(tagvalue) and
118 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM,
119 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM+DT_ADDRNUM)
120 are indexed by DT_ADDRTAGIDX(tagvalue), see <elf.h>. */
122 ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
123 + DT_EXTRANUM + DT_VALNUM + DT_ADDRNUM];
124 const ElfW(Phdr) *l_phdr; /* Pointer to program header table in core. */
125 ElfW(Addr) l_entry; /* Entry point location. */
126 ElfW(Half) l_phnum; /* Number of program header entries. */
127 ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */
129 /* Array of DT_NEEDED dependencies and their dependencies, in
130 dependency order for symbol lookup (with and without
131 duplicates). There is no entry before the dependencies have
132 been loaded. */
133 struct r_scope_elem l_searchlist;
135 /* We need a special searchlist to process objects marked with
136 DT_SYMBOLIC. */
137 struct r_scope_elem l_symbolic_searchlist;
139 /* Dependent object that first caused this object to be loaded. */
140 struct link_map *l_loader;
142 /* Symbol hash table. */
143 Elf_Symndx l_nbuckets;
144 const Elf_Symndx *l_buckets, *l_chain;
146 unsigned int l_direct_opencount; /* Reference count for dlopen/dlclose. */
147 enum /* Where this object came from. */
149 lt_executable, /* The main executable program. */
150 lt_library, /* Library needed by main executable. */
151 lt_loaded /* Extra run-time loaded shared object. */
152 } l_type:2;
153 unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
154 unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
155 unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */
156 unsigned int l_reserved:2; /* Reserved for internal use. */
157 unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
158 to by `l_phdr' is allocated. */
159 unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
160 the l_libname list. */
161 unsigned int l_faked:1; /* Nonzero if this is a faked descriptor
162 without associated file. */
163 unsigned int l_need_tls_init:1; /* Nonzero if GL(dl_init_static_tls)
164 should be called on this link map
165 when relocation finishes. */
166 unsigned int l_used:1; /* Nonzero if the DSO is used. */
167 unsigned int l_auditing:1; /* Nonzero if the DSO is used in auditing. */
168 unsigned int l_audit_any_plt:1; /* Nonzero if at least one audit module
169 is interested in the PLT interception.*/
170 unsigned int l_removed:1; /* Nozero if the object cannot be used anymore
171 since it is removed. */
173 /* Array with version names. */
174 unsigned int l_nversions;
175 struct r_found_version *l_versions;
177 /* Collected information about own RPATH directories. */
178 struct r_search_path_struct l_rpath_dirs;
180 /* Collected results of relocation while profiling. */
181 struct reloc_result
183 DL_FIXUP_VALUE_TYPE addr;
184 struct link_map *bound;
185 unsigned int boundndx;
186 uint32_t enterexit;
187 unsigned int flags;
188 } *l_reloc_result;
190 /* Pointer to the version information if available. */
191 ElfW(Versym) *l_versyms;
193 /* String specifying the path where this object was found. */
194 const char *l_origin;
196 /* Start and finish of memory map for this object. l_map_start
197 need not be the same as l_addr. */
198 ElfW(Addr) l_map_start, l_map_end;
199 /* End of the executable part of the mapping. */
200 ElfW(Addr) l_text_end;
202 /* Default array for 'l_scope'. */
203 struct r_scope_elem *l_scope_mem[4];
204 /* Size of array allocated for 'l_scope'. */
205 size_t l_scope_max;
206 /* This is an array defining the lookup scope for this link map.
207 There are at most three different scope lists. */
208 struct r_scope_elem **l_scope;
210 /* A similar array, this time only with the local scope. This is
211 used occasionally. */
212 struct r_scope_elem *l_local_scope[2];
214 /* This information is kept to check for sure whether a shared
215 object is the same as one already loaded. */
216 dev_t l_dev;
217 ino64_t l_ino;
219 /* Collected information about own RUNPATH directories. */
220 struct r_search_path_struct l_runpath_dirs;
222 /* List of object in order of the init and fini calls. */
223 struct link_map **l_initfini;
225 /* List of the dependencies introduced through symbol binding. */
226 unsigned int l_reldepsmax;
227 unsigned int l_reldepsact;
228 struct link_map **l_reldeps;
230 /* Various flag words. */
231 ElfW(Word) l_feature_1;
232 ElfW(Word) l_flags_1;
233 ElfW(Word) l_flags;
235 /* Temporarily used in `dl_close'. */
236 int l_idx;
238 struct link_map_machine l_mach;
240 struct
242 const ElfW(Sym) *sym;
243 int type_class;
244 struct link_map *value;
245 const ElfW(Sym) *ret;
246 } l_lookup_cache;
248 #ifdef USE_TLS
249 /* Thread-local storage related info. */
251 /* Start of the initialization image. */
252 void *l_tls_initimage;
253 /* Size of the initialization image. */
254 size_t l_tls_initimage_size;
255 /* Size of the TLS block. */
256 size_t l_tls_blocksize;
257 /* Alignment requirement of the TLS block. */
258 size_t l_tls_align;
259 /* Offset of first byte module alignment. */
260 size_t l_tls_firstbyte_offset;
261 # ifndef NO_TLS_OFFSET
262 # define NO_TLS_OFFSET 0
263 # endif
264 /* For objects present at startup time: offset in the static TLS block. */
265 ptrdiff_t l_tls_offset;
266 /* Index of the module in the dtv array. */
267 size_t l_tls_modid;
268 #endif
270 /* Information used to change permission after the relocations are
271 done. */
272 ElfW(Addr) l_relro_addr;
273 size_t l_relro_size;
275 /* Audit information. This array apparent must be the last in the
276 structure. Never add something after it. */
277 struct auditstate
279 uintptr_t cookie;
280 unsigned int bindflags;
281 } l_audit[0];
285 #if __ELF_NATIVE_CLASS == 32
286 # define symbind symbind32
287 #elif __ELF_NATIVE_CLASS == 64
288 # define symbind symbind64
289 #else
290 # error "__ELF_NATIVE_CLASS must be defined"
291 #endif
293 extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
294 size_t size, void *data),
295 void *data);
297 #endif /* include/link.h */