1 | /* User functions for run-time dynamic loading. |
2 | Copyright (C) 1995-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #ifndef _DLFCN_H |
20 | #define _DLFCN_H 1 |
21 | |
22 | #include <features.h> |
23 | #define __need_size_t |
24 | #include <stddef.h> |
25 | |
26 | /* Collect various system dependent definitions and declarations. */ |
27 | #include <bits/dlfcn.h> |
28 | |
29 | |
30 | #ifdef __USE_GNU |
31 | #include <bits/dl_find_object.h> |
32 | |
33 | /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT |
34 | the run-time address of the symbol called NAME in the next shared |
35 | object is returned. The "next" relation is defined by the order |
36 | the shared objects were loaded. */ |
37 | # define RTLD_NEXT ((void *) -1l) |
38 | |
39 | /* If the first argument to `dlsym' or `dlvsym' is set to RTLD_DEFAULT |
40 | the run-time address of the symbol called NAME in the global scope |
41 | is returned. */ |
42 | # define RTLD_DEFAULT ((void *) 0) |
43 | |
44 | |
45 | /* Type for namespace indices. */ |
46 | typedef long int Lmid_t; |
47 | |
48 | /* Special namespace ID values. */ |
49 | # define LM_ID_BASE 0 /* Initial namespace. */ |
50 | # define LM_ID_NEWLM -1 /* For dlmopen: request new namespace. */ |
51 | #endif |
52 | |
53 | |
54 | __BEGIN_DECLS |
55 | |
56 | /* Open the shared object FILE and map it in; return a handle that can be |
57 | passed to `dlsym' to get symbol values from it. */ |
58 | extern void *dlopen (const char *__file, int __mode) __THROWNL; |
59 | |
60 | /* Unmap and close a shared object opened by `dlopen'. |
61 | The handle cannot be used again after calling `dlclose'. */ |
62 | extern int dlclose (void *__handle) __THROWNL __nonnull ((1)); |
63 | |
64 | /* Find the run-time address in the shared object HANDLE refers to |
65 | of the symbol called NAME. */ |
66 | extern void *dlsym (void *__restrict __handle, |
67 | const char *__restrict __name) __THROW __nonnull ((2)); |
68 | |
69 | #ifdef __USE_GNU |
70 | /* Like `dlopen', but request object to be allocated in a new namespace. */ |
71 | extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROWNL; |
72 | |
73 | /* Find the run-time address in the shared object HANDLE refers to |
74 | of the symbol called NAME with VERSION. */ |
75 | extern void *dlvsym (void *__restrict __handle, |
76 | const char *__restrict __name, |
77 | const char *__restrict __version) |
78 | __THROW __nonnull ((2, 3)); |
79 | #endif |
80 | |
81 | /* When any of the above functions fails, call this function |
82 | to return a string describing the error. Each call resets |
83 | the error string so that a following call returns null. */ |
84 | extern char *dlerror (void) __THROW; |
85 | |
86 | |
87 | #ifdef __USE_GNU |
88 | /* Structure containing information about object searched using |
89 | `dladdr'. */ |
90 | typedef struct |
91 | { |
92 | const char *dli_fname; /* File name of defining object. */ |
93 | void *dli_fbase; /* Load address of that object. */ |
94 | const char *dli_sname; /* Name of nearest symbol. */ |
95 | void *dli_saddr; /* Exact value of nearest symbol. */ |
96 | } Dl_info; |
97 | |
98 | /* Fill in *INFO with the following information about ADDRESS. |
99 | Returns 0 iff no shared object's segments contain that address. */ |
100 | extern int dladdr (const void *__address, Dl_info *__info) |
101 | __THROW __nonnull ((2)); |
102 | |
103 | /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS. */ |
104 | extern int dladdr1 (const void *__address, Dl_info *__info, |
105 | void **, int __flags) __THROW __nonnull ((2)); |
106 | |
107 | /* These are the possible values for the FLAGS argument to `dladdr1'. |
108 | This indicates what extra information is stored at *EXTRA_INFO. |
109 | It may also be zero, in which case the EXTRA_INFO argument is not used. */ |
110 | enum |
111 | { |
112 | /* Matching symbol table entry (const ElfNN_Sym *). */ |
113 | RTLD_DL_SYMENT = 1, |
114 | |
115 | /* The object containing the address (struct link_map *). */ |
116 | RTLD_DL_LINKMAP = 2 |
117 | }; |
118 | |
119 | |
120 | /* Get information about the shared object HANDLE refers to. |
121 | REQUEST is from among the values below, and determines the use of ARG. |
122 | |
123 | On success, returns zero. On failure, returns -1 and records an error |
124 | message to be fetched with `dlerror'. */ |
125 | extern int dlinfo (void *__restrict __handle, |
126 | int __request, void *__restrict __arg) |
127 | __THROW __nonnull ((1, 3)); |
128 | |
129 | /* These are the possible values for the REQUEST argument to `dlinfo'. */ |
130 | enum |
131 | { |
132 | /* Treat ARG as `lmid_t *'; store namespace ID for HANDLE there. */ |
133 | RTLD_DI_LMID = 1, |
134 | |
135 | /* Treat ARG as `struct link_map **'; |
136 | store the `struct link_map *' for HANDLE there. */ |
137 | RTLD_DI_LINKMAP = 2, |
138 | |
139 | RTLD_DI_CONFIGADDR = 3, /* Unsupported, defined by Solaris. */ |
140 | |
141 | /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the |
142 | directories that will be searched for dependencies of this object. |
143 | RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size' |
144 | entries to indicate the size of the buffer that must be passed to |
145 | RTLD_DI_SERINFO to fill in the full information. */ |
146 | RTLD_DI_SERINFO = 4, |
147 | RTLD_DI_SERINFOSIZE = 5, |
148 | |
149 | /* Treat ARG as `char *', and store there the directory name used to |
150 | expand $ORIGIN in this shared object's dependency file names. */ |
151 | RTLD_DI_ORIGIN = 6, |
152 | |
153 | RTLD_DI_PROFILENAME = 7, /* Unsupported, defined by Solaris. */ |
154 | RTLD_DI_PROFILEOUT = 8, /* Unsupported, defined by Solaris. */ |
155 | |
156 | /* Treat ARG as `size_t *', and store there the TLS module ID |
157 | of this object's PT_TLS segment, as used in TLS relocations; |
158 | store zero if this object does not define a PT_TLS segment. */ |
159 | RTLD_DI_TLS_MODID = 9, |
160 | |
161 | /* Treat ARG as `void **', and store there a pointer to the calling |
162 | thread's TLS block corresponding to this object's PT_TLS segment. |
163 | Store a null pointer if this object does not define a PT_TLS |
164 | segment, or if the calling thread has not allocated a block for it. */ |
165 | RTLD_DI_TLS_DATA = 10, |
166 | |
167 | RTLD_DI_MAX = 10 |
168 | }; |
169 | |
170 | |
171 | /* This is the type of elements in `Dl_serinfo', below. |
172 | The `dls_name' member points to space in the buffer passed to `dlinfo'. */ |
173 | typedef struct |
174 | { |
175 | char *dls_name; /* Name of library search path directory. */ |
176 | unsigned int dls_flags; /* Indicates where this directory came from. */ |
177 | } Dl_serpath; |
178 | |
179 | /* This is the structure that must be passed (by reference) to `dlinfo' for |
180 | the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests. */ |
181 | typedef struct |
182 | { |
183 | size_t dls_size; /* Size in bytes of the whole buffer. */ |
184 | unsigned int dls_cnt; /* Number of elements in `dls_serpath'. */ |
185 | # if __GNUC_PREREQ (3, 0) |
186 | /* The zero-length array avoids an unwanted array subscript check by |
187 | the compiler, while the surrounding anonymous union preserves the |
188 | historic size of the type. At the time of writing, GNU C does |
189 | not support structs with flexible array members in unions. */ |
190 | __extension__ union |
191 | { |
192 | Dl_serpath dls_serpath[0]; /* Actually longer, dls_cnt elements. */ |
193 | Dl_serpath __dls_serpath_pad[1]; |
194 | }; |
195 | # else |
196 | Dl_serpath dls_serpath[1]; /* Actually longer, dls_cnt elements. */ |
197 | # endif |
198 | } Dl_serinfo; |
199 | |
200 | struct dl_find_object |
201 | { |
202 | __extension__ unsigned long long int dlfo_flags; |
203 | void *dlfo_map_start; /* Beginning of mapping containing address. */ |
204 | void *dlfo_map_end; /* End of mapping. */ |
205 | struct link_map *dlfo_link_map; |
206 | void *dlfo_eh_frame; /* Exception handling data of the object. */ |
207 | # if DLFO_STRUCT_HAS_EH_DBASE |
208 | void *dlfo_eh_dbase; /* Base address for DW_EH_PE_datarel. */ |
209 | # if __WORDSIZE == 32 |
210 | unsigned int __dlfo_eh_dbase_pad; |
211 | # endif |
212 | # endif |
213 | # if DLFO_STRUCT_HAS_EH_COUNT |
214 | int dlfo_eh_count; /* Number of exception handling entries. */ |
215 | unsigned int __dlfo_eh_count_pad; |
216 | # endif |
217 | __extension__ unsigned long long int __dflo_reserved[7]; |
218 | }; |
219 | |
220 | /* If ADDRESS is found in an object, fill in *RESULT and return 0. |
221 | Otherwise, return -1. */ |
222 | int _dl_find_object (void *__address, struct dl_find_object *__result) __THROW; |
223 | |
224 | #endif /* __USE_GNU */ |
225 | |
226 | |
227 | __END_DECLS |
228 | |
229 | #endif /* dlfcn.h */ |
230 | |