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[glibc/history.git] / include / link.h
blob4b9978ad61c5d935f0a6c943fdc90c940f03a923
1 /* Data structure for communication from the run-time dynamic linker for
2 loaded ELF shared objects.
3 Copyright (C) 1995-2006, 2007 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>
46 #include <bits/libc-lock.h>
49 /* Some internal data structures of the dynamic linker used in the
50 linker map. We only provide forward declarations. */
51 struct libname_list;
52 struct r_found_version;
53 struct r_search_path_elem;
55 /* Forward declaration. */
56 struct link_map;
58 /* Structure to describe a single list of scope elements. The lookup
59 functions get passed an array of pointers to such structures. */
60 struct r_scope_elem
62 /* Array of maps for the scope. */
63 struct link_map **r_list;
64 /* Number of entries in the scope. */
65 unsigned int r_nlist;
69 /* Structure to record search path and allocation mechanism. */
70 struct r_search_path_struct
72 struct r_search_path_elem **dirs;
73 int malloced;
77 /* Structure describing a loaded shared object. The `l_next' and `l_prev'
78 members form a chain of all the shared objects loaded at startup.
80 These data structures exist in space used by the run-time dynamic linker;
81 modifying them may have disastrous results.
83 This data structure might change in future, if necessary. User-level
84 programs must avoid defining objects of this type. */
86 struct link_map
88 /* These first few members are part of the protocol with the debugger.
89 This is the same format used in SVR4. */
91 ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
92 char *l_name; /* Absolute file name object was found in. */
93 ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
94 struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
96 /* All following members are internal to the dynamic linker.
97 They may change without notice. */
99 /* This is an element which is only ever different from a pointer to
100 the very same copy of this type for ld.so when it is used in more
101 than one namespace. */
102 struct link_map *l_real;
104 /* Number of the namespace this link map belongs to. */
105 Lmid_t l_ns;
107 struct libname_list *l_libname;
108 /* Indexed pointers to dynamic section.
109 [0,DT_NUM) are indexed by the processor-independent tags.
110 [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
111 [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM) are
112 indexed by DT_VERSIONTAGIDX(tagvalue).
113 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
114 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM) are indexed by
115 DT_EXTRATAGIDX(tagvalue).
116 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM,
117 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM) are
118 indexed by DT_VALTAGIDX(tagvalue) and
119 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM,
120 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM+DT_ADDRNUM)
121 are indexed by DT_ADDRTAGIDX(tagvalue), see <elf.h>. */
123 ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
124 + DT_EXTRANUM + DT_VALNUM + DT_ADDRNUM];
125 const ElfW(Phdr) *l_phdr; /* Pointer to program header table in core. */
126 ElfW(Addr) l_entry; /* Entry point location. */
127 ElfW(Half) l_phnum; /* Number of program header entries. */
128 ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */
130 /* Array of DT_NEEDED dependencies and their dependencies, in
131 dependency order for symbol lookup (with and without
132 duplicates). There is no entry before the dependencies have
133 been loaded. */
134 struct r_scope_elem l_searchlist;
136 /* We need a special searchlist to process objects marked with
137 DT_SYMBOLIC. */
138 struct r_scope_elem l_symbolic_searchlist;
140 /* Dependent object that first caused this object to be loaded. */
141 struct link_map *l_loader;
143 /* Array with version names. */
144 struct r_found_version *l_versions;
145 unsigned int l_nversions;
147 /* Symbol hash table. */
148 Elf_Symndx l_nbuckets;
149 Elf32_Word l_gnu_bitmask_idxbits;
150 Elf32_Word l_gnu_shift;
151 const ElfW(Addr) *l_gnu_bitmask;
152 union
154 const Elf32_Word *l_gnu_buckets;
155 const Elf_Symndx *l_chain;
157 union
159 const Elf32_Word *l_gnu_chain_zero;
160 const Elf_Symndx *l_buckets;
163 unsigned int l_direct_opencount; /* Reference count for dlopen/dlclose. */
164 enum /* Where this object came from. */
166 lt_executable, /* The main executable program. */
167 lt_library, /* Library needed by main executable. */
168 lt_loaded /* Extra run-time loaded shared object. */
169 } l_type:2;
170 unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
171 unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
172 unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */
173 unsigned int l_reserved:2; /* Reserved for internal use. */
174 unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
175 to by `l_phdr' is allocated. */
176 unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
177 the l_libname list. */
178 unsigned int l_faked:1; /* Nonzero if this is a faked descriptor
179 without associated file. */
180 unsigned int l_need_tls_init:1; /* Nonzero if GL(dl_init_static_tls)
181 should be called on this link map
182 when relocation finishes. */
183 unsigned int l_used:1; /* Nonzero if the DSO is used. */
184 unsigned int l_auditing:1; /* Nonzero if the DSO is used in auditing. */
185 unsigned int l_audit_any_plt:1; /* Nonzero if at least one audit module
186 is interested in the PLT interception.*/
187 unsigned int l_removed:1; /* Nozero if the object cannot be used anymore
188 since it is removed. */
189 unsigned int l_contiguous:1; /* Nonzero if inter-segment holes are
190 mprotected or if no holes are present at
191 all. */
193 /* Collected information about own RPATH directories. */
194 struct r_search_path_struct l_rpath_dirs;
196 /* Collected results of relocation while profiling. */
197 struct reloc_result
199 DL_FIXUP_VALUE_TYPE addr;
200 struct link_map *bound;
201 unsigned int boundndx;
202 uint32_t enterexit;
203 unsigned int flags;
204 } *l_reloc_result;
206 /* Pointer to the version information if available. */
207 ElfW(Versym) *l_versyms;
209 /* String specifying the path where this object was found. */
210 const char *l_origin;
212 /* Start and finish of memory map for this object. l_map_start
213 need not be the same as l_addr. */
214 ElfW(Addr) l_map_start, l_map_end;
215 /* End of the executable part of the mapping. */
216 ElfW(Addr) l_text_end;
218 /* Default array for 'l_scope'. */
219 struct r_scope_elem *l_scope_mem[4];
220 /* Size of array allocated for 'l_scope'. */
221 size_t l_scope_max;
222 /* This is an array defining the lookup scope for this link map.
223 There are initially at most three different scope lists. */
224 struct r_scope_elem **l_scope;
226 /* A similar array, this time only with the local scope. This is
227 used occasionally. */
228 struct r_scope_elem *l_local_scope[2];
230 /* This information is kept to check for sure whether a shared
231 object is the same as one already loaded. */
232 dev_t l_dev;
233 ino64_t l_ino;
235 /* Collected information about own RUNPATH directories. */
236 struct r_search_path_struct l_runpath_dirs;
238 /* List of object in order of the init and fini calls. */
239 struct link_map **l_initfini;
241 /* List of the dependencies introduced through symbol binding. */
242 unsigned int l_reldepsmax;
243 struct link_map_reldeps
245 unsigned int act;
246 struct link_map *list[];
247 } *l_reldeps;
249 /* Various flag words. */
250 ElfW(Word) l_feature_1;
251 ElfW(Word) l_flags_1;
252 ElfW(Word) l_flags;
254 /* Temporarily used in `dl_close'. */
255 int l_idx;
257 struct link_map_machine l_mach;
259 struct
261 const ElfW(Sym) *sym;
262 int type_class;
263 struct link_map *value;
264 const ElfW(Sym) *ret;
265 } l_lookup_cache;
267 /* Thread-local storage related info. */
269 /* Start of the initialization image. */
270 void *l_tls_initimage;
271 /* Size of the initialization image. */
272 size_t l_tls_initimage_size;
273 /* Size of the TLS block. */
274 size_t l_tls_blocksize;
275 /* Alignment requirement of the TLS block. */
276 size_t l_tls_align;
277 /* Offset of first byte module alignment. */
278 size_t l_tls_firstbyte_offset;
279 #ifndef NO_TLS_OFFSET
280 # define NO_TLS_OFFSET 0
281 #endif
282 #ifndef FORCED_DYNAMIC_TLS_OFFSET
283 # if NO_TLS_OFFSET == 0
284 # define FORCED_DYNAMIC_TLS_OFFSET 1
285 # elif NO_TLS_OFFSET == -1
286 # define FORCED_DYNAMIC_TLS_OFFSET -2
287 # else
288 # error "FORCED_DYNAMIC_TLS_OFFSET is not defined"
289 # endif
290 #endif
291 /* For objects present at startup time: offset in the static TLS block. */
292 ptrdiff_t l_tls_offset;
293 /* Index of the module in the dtv array. */
294 size_t l_tls_modid;
296 /* Information used to change permission after the relocations are
297 done. */
298 ElfW(Addr) l_relro_addr;
299 size_t l_relro_size;
301 unsigned long long int l_serial;
303 /* Audit information. This array apparent must be the last in the
304 structure. Never add something after it. */
305 struct auditstate
307 uintptr_t cookie;
308 unsigned int bindflags;
309 } l_audit[0];
313 #if __ELF_NATIVE_CLASS == 32
314 # define symbind symbind32
315 #elif __ELF_NATIVE_CLASS == 64
316 # define symbind symbind64
317 #else
318 # error "__ELF_NATIVE_CLASS must be defined"
319 #endif
321 extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
322 size_t size, void *data),
323 void *data);
325 #endif /* include/link.h */