1 /* Data structure for communication from the run-time dynamic linker for
2 loaded ELF shared objects.
3 Copyright (C) 1995-2001, 2004, 2005, 2006, 2010 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, see
18 <http://www.gnu.org/licenses/>. */
25 #ifdef __HAVE_SHARED__
28 #include <sys/types.h>
29 #if defined _LIBC && defined __UCLIBC_HAS_TLS__
33 /* We use this macro to refer to ELF types independent of the native wordsize.
34 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
35 #define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type)
36 #define _ElfW(e,w,t) _ElfW_1 (e, w, _##t)
37 #define _ElfW_1(e,w,t) e##w##t
39 #include <bits/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */
41 /* Rendezvous structure used by the run-time dynamic linker to communicate
42 details of shared object loading to the debugger. If the executable's
43 dynamic section has a DT_DEBUG element, the run-time linker sets that
44 element's value to the address where this structure can be found. */
48 int r_version; /* Version number for this protocol. */
50 struct link_map *r_map; /* Head of the chain of loaded objects. */
52 /* This is the address of a function internal to the run-time linker,
53 that will always be called when the linker begins to map in a
54 library or unmap it, and again when the mapping change is complete.
55 The debugger can set a breakpoint at this address if it wants to
56 notice shared object mapping changes. */
60 /* This state value describes the mapping change taking place when
61 the `r_brk' address is called. */
62 RT_CONSISTENT, /* Mapping change is complete. */
63 RT_ADD, /* Beginning to add a new object. */
64 RT_DELETE /* Beginning to remove an object mapping. */
67 ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */
70 /* This is the instance of that structure used by the dynamic linker. */
71 extern struct r_debug _r_debug;
73 /* This symbol refers to the "dynamic structure" in the `.dynamic' section
74 of whatever module refers to `_DYNAMIC'. So, to find its own
75 `struct r_debug', a program could do:
76 for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)
77 if (dyn->d_tag == DT_DEBUG)
78 r_debug = (struct r_debug *) dyn->d_un.d_ptr;
80 extern ElfW(Dyn) _DYNAMIC[];
83 # include <bits/elf-fdpic.h>
86 # include <bits/elf-dsbt.h>
89 /* Structure describing a loaded shared object. The `l_next' and `l_prev'
90 members form a chain of all the shared objects loaded at startup.
92 These data structures exist in space used by the run-time dynamic linker;
93 modifying them may have disastrous results. */
97 /* These first few members are part of the protocol with the debugger.
98 This is the same format used in SVR4. */
101 struct elf32_fdpic_loadaddr l_addr;
104 struct elf32_dsbt_loadaddr l_addr;
106 ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
109 char *l_name; /* Absolute file name object was found in. */
110 ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
111 struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
113 #if defined(USE_TLS) && USE_TLS
114 /* Thread-local storage related info. */
116 /* Start of the initialization image. */
117 void *l_tls_initimage;
118 /* Size of the initialization image. */
119 size_t l_tls_initimage_size;
120 /* Size of the TLS block. */
121 size_t l_tls_blocksize;
122 /* Alignment requirement of the TLS block. */
124 /* Offset of first byte module alignment. */
125 size_t l_tls_firstbyte_offset;
126 # ifndef NO_TLS_OFFSET
127 # define NO_TLS_OFFSET 0
129 /* For objects present at startup time: offset in the static TLS block. */
130 ptrdiff_t l_tls_offset;
131 /* Index of the module in the dtv array. */
133 /* Nonzero if _dl_init_static_tls should be called for this module */
134 unsigned int l_need_tls_init:1;
142 /* Version numbers for la_version handshake interface. */
143 #define LAV_CURRENT 1
145 /* Activity types signaled through la_activity. */
148 LA_ACT_CONSISTENT, /* Link map consistent again. */
149 LA_ACT_ADD, /* New object will be added. */
150 LA_ACT_DELETE /* Objects will be removed. */
153 /* Values representing origin of name for dynamic loading. */
156 LA_SER_ORIG = 0x01, /* Original name. */
157 LA_SER_LIBPATH = 0x02, /* Directory from LD_LIBRARY_PATH. */
158 LA_SER_RUNPATH = 0x04, /* Directory from RPATH/RUNPATH. */
159 LA_SER_CONFIG = 0x08, /* Found through ldconfig. */
160 LA_SER_DEFAULT = 0x40, /* Default directory. */
161 LA_SER_SECURE = 0x80 /* Unused. */
164 /* Values for la_objopen return value. */
167 LA_FLG_BINDTO = 0x01, /* Audit symbols bound to this object. */
168 LA_FLG_BINDFROM = 0x02 /* Audit symbols bound from this object. */
171 /* Values for la_symbind flags parameter. */
174 LA_SYMB_NOPLTENTER = 0x01, /* la_pltenter will not be called. */
175 LA_SYMB_NOPLTEXIT = 0x02, /* la_pltexit will not be called. */
176 LA_SYMB_STRUCTCALL = 0x04, /* Return value is a structure. */
177 LA_SYMB_DLSYM = 0x08, /* Binding due to dlsym call. */
178 LA_SYMB_ALTVALUE = 0x10 /* Value has been changed by a previous
186 struct elf32_fdpic_loadaddr dlpi_addr;
189 struct elf32_dsbt_loadaddr dlpi_addr;
191 ElfW(Addr) dlpi_addr;
194 const char *dlpi_name;
195 const ElfW(Phdr) *dlpi_phdr;
196 ElfW(Half) dlpi_phnum;
199 /* Note: Following members were introduced after the first
200 version of this structure was available. Check the SIZE
201 argument passed to the dl_iterate_phdr callback to determine
202 whether or not each later member is available. */
204 /* Incremented when a new object may have been added. */
205 unsigned long long int dlpi_adds;
206 /* Incremented when an object may have been removed. */
207 unsigned long long int dlpi_subs;
209 /* If there is a PT_TLS segment, its module ID as used in
210 TLS relocations, else zero. */
211 size_t dlpi_tls_modid;
213 /* The address of the calling thread's instance of this module's
214 PT_TLS segment, if it has one and it has been allocated
215 in the calling thread, otherwise a null pointer. */
222 extern int dl_iterate_phdr (int (*__callback) (struct dl_phdr_info *,
228 /* Prototypes for the ld.so auditing interfaces. These are not
229 defined anywhere in ld.so but instead have to be provided by the
231 extern unsigned int la_version (unsigned int __version);
232 extern void la_activity (uintptr_t *__cookie, unsigned int __flag);
233 extern char *la_objsearch (const char *__name, uintptr_t *__cookie,
234 unsigned int __flag);
235 extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid,
236 uintptr_t *__cookie);
237 extern void la_preinit (uintptr_t *__cookie);
238 extern uintptr_t la_symbind32 (Elf32_Sym *__sym, unsigned int __ndx,
239 uintptr_t *__refcook, uintptr_t *__defcook,
240 unsigned int *__flags, const char *__symname);
241 extern uintptr_t la_symbind64 (Elf64_Sym *__sym, unsigned int __ndx,
242 uintptr_t *__refcook, uintptr_t *__defcook,
243 unsigned int *__flags, const char *__symname);
244 extern unsigned int la_objclose (uintptr_t *__cookie);