* sysdeps/m68k/setjmp.c: Also define setjmp and _setjmp if
[glibc.git] / include / link.h
blob77c1851736730693ad21fbcc52524d7ddc46bf07
1 /* Data structure for communication from the run-time dynamic linker for
2 loaded ELF shared objects.
3 Copyright (C) 1995-1999, 2000, 2001 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 _LINK_H
22 #define _LINK_H 1
24 #include <features.h>
25 #include <elf.h>
26 #include <dlfcn.h>
27 #include <sys/types.h>
29 /* We use this macro to refer to ELF types independent of the native wordsize.
30 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
31 #define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type)
32 #define _ElfW(e,w,t) _ElfW_1 (e, w, _##t)
33 #define _ElfW_1(e,w,t) e##w##t
35 #include <bits/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */
36 #include <bits/link.h>
37 #include <dl-lookupcfg.h>
39 /* Rendezvous structure used by the run-time dynamic linker to communicate
40 details of shared object loading to the debugger. If the executable's
41 dynamic section has a DT_DEBUG element, the run-time linker sets that
42 element's value to the address where this structure can be found. */
44 struct r_debug
46 int r_version; /* Version number for this protocol. */
48 struct link_map *r_map; /* Head of the chain of loaded objects. */
50 /* This is the address of a function internal to the run-time linker,
51 that will always be called when the linker begins to map in a
52 library or unmap it, and again when the mapping change is complete.
53 The debugger can set a breakpoint at this address if it wants to
54 notice shared object mapping changes. */
55 ElfW(Addr) r_brk;
56 enum
58 /* This state value describes the mapping change taking place when
59 the `r_brk' address is called. */
60 RT_CONSISTENT, /* Mapping change is complete. */
61 RT_ADD, /* Beginning to add a new object. */
62 RT_DELETE /* Beginning to remove an object mapping. */
63 } r_state;
65 ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */
68 /* This is the instance of that structure used by the dynamic linker. */
69 extern struct r_debug _r_debug;
71 /* This symbol refers to the "dynamic structure" in the `.dynamic' section
72 of whatever module refers to `_DYNAMIC'. So, to find its own
73 `struct r_debug', a program could do:
74 for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)
75 if (dyn->d_tag == DT_DEBUG)
76 r_debug = (struct r_debug *) dyn->d_un.d_ptr;
78 extern ElfW(Dyn) _DYNAMIC[];
81 /* Some internal data structures of the dynamic linker used in the
82 linker map. We only provide forward declarations. */
83 struct libname_list;
84 struct r_found_version;
85 struct r_search_path_elem;
87 /* Forward declaration. */
88 struct link_map;
90 /* Structure to describe a single list of scope elements. The lookup
91 functions get passed an array of pointers to such structures. */
92 struct r_scope_elem
94 /* Array of maps for the scope. */
95 struct link_map **r_list;
96 /* Number of entries in the scope. */
97 unsigned int r_nlist;
101 /* Structure to record search path and allocation mechanism. */
102 struct r_search_path_struct
104 struct r_search_path_elem **dirs;
105 int malloced;
109 /* Structure describing a loaded shared object. The `l_next' and `l_prev'
110 members form a chain of all the shared objects loaded at startup.
112 These data structures exist in space used by the run-time dynamic linker;
113 modifying them may have disastrous results.
115 This data structure might change in future, if necessary. User-level
116 programs must avoid defining objects of this type. */
118 struct link_map
120 /* These first few members are part of the protocol with the debugger.
121 This is the same format used in SVR4. */
123 ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
124 char *l_name; /* Absolute file name object was found in. */
125 ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
126 struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
128 /* All following members are internal to the dynamic linker.
129 They may change without notice. */
131 struct libname_list *l_libname;
132 /* Indexed pointers to dynamic section.
133 [0,DT_NUM) are indexed by the processor-independent tags.
134 [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
135 [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_EXTRANUM) are indexed
136 by DT_EXTRATAGIDX(tagvalue) and
137 [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
138 DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM)
139 are indexed by DT_EXTRATAGIDX(tagvalue) (see <elf.h>). */
141 ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
142 + DT_EXTRANUM];
143 const ElfW(Phdr) *l_phdr; /* Pointer to program header table in core. */
144 ElfW(Addr) l_entry; /* Entry point location. */
145 ElfW(Half) l_phnum; /* Number of program header entries. */
146 ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */
148 /* Array of DT_NEEDED dependencies and their dependencies, in
149 dependency order for symbol lookup (with and without
150 duplicates). There is no entry before the dependencies have
151 been loaded. */
152 struct r_scope_elem l_searchlist;
154 /* We need a special searchlist to process objects marked with
155 DT_SYMBOLIC. */
156 struct r_scope_elem l_symbolic_searchlist;
158 /* Dependent object that first caused this object to be loaded. */
159 struct link_map *l_loader;
161 /* Symbol hash table. */
162 Elf_Symndx l_nbuckets;
163 const Elf_Symndx *l_buckets, *l_chain;
165 unsigned int l_opencount; /* Reference count for dlopen/dlclose. */
166 enum /* Where this object came from. */
168 lt_executable, /* The main executable program. */
169 lt_library, /* Library needed by main executable. */
170 lt_loaded /* Extra run-time loaded shared object. */
171 } l_type:2;
172 unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
173 unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
174 unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */
175 unsigned int l_reserved:2; /* Reserved for internal use. */
176 unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
177 to by `l_phdr' is allocated. */
178 unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
179 the l_libname list. */
180 unsigned int l_faked:1; /* Nonzero if this is a faked descriptor
181 without associated file. */
183 /* Array with version names. */
184 unsigned int l_nversions;
185 struct r_found_version *l_versions;
187 /* Collected information about own RPATH directories. */
188 struct r_search_path_struct l_rpath_dirs;
190 /* Collected results of relocation while profiling. */
191 ElfW(Addr) *l_reloc_result;
193 /* Pointer to the version information if available. */
194 ElfW(Versym) *l_versyms;
196 /* String specifying the path where this object was found. */
197 const char *l_origin;
199 /* Start and finish of memory map for this object. l_map_start
200 need not be the same as l_addr. */
201 ElfW(Addr) l_map_start, l_map_end;
203 /* Default array for 'l_scope'. */
204 struct r_scope_elem *l_scope_mem[4];
205 /* Size of array allocated for 'l_scope'. */
206 size_t l_scope_max;
207 /* This is an array defining the lookup scope for this link map.
208 There are at most three different scope lists. */
209 struct r_scope_elem **l_scope;
211 /* A similar array, this time only with the local scope. This is
212 used occasionally. */
213 struct r_scope_elem *l_local_scope[2];
215 /* This information is kept to check for sure whether a shared
216 object is the same as one already loaded. */
217 dev_t l_dev;
218 ino64_t l_ino;
220 /* Collected information about own RUNPATH directories. */
221 struct r_search_path_struct l_runpath_dirs;
223 /* List of object in order of the init and fini calls. */
224 struct link_map **l_initfini;
226 /* List of the dependencies introduced through symbol binding. */
227 unsigned int l_reldepsmax;
228 unsigned int l_reldepsact;
229 struct link_map **l_reldeps;
231 /* Various flag words. */
232 ElfW(Word) l_feature_1;
233 ElfW(Word) l_flags_1;
235 /* Temporarily used in `dl_close'. */
236 unsigned int l_idx;
238 struct link_map_machine l_mach;
240 struct
242 const ElfW(Sym) *sym;
243 int type_class;
244 #ifdef DL_LOOKUP_RETURNS_MAP
245 struct link_map *value;
246 #else
247 ElfW(Addr) value;
248 #endif
249 const ElfW(Sym) *ret;
250 } l_lookup_cache;
253 struct dl_phdr_info
255 ElfW(Addr) dlpi_addr;
256 const char *dlpi_name;
257 const ElfW(Phdr) *dlpi_phdr;
258 ElfW(Half) dlpi_phnum;
261 extern int dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
262 size_t size, void *data),
263 void *data);
264 extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
265 size_t size, void *data),
266 void *data);
268 #endif /* link.h */