dlfcn.h 8.6 KB

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  1. /* User functions for run-time dynamic loading.
  2. Copyright (C) 1995-2026 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <https://www.gnu.org/licenses/>. */
  15. #ifndef _DLFCN_H
  16. #define _DLFCN_H 1
  17. #include <features.h>
  18. #define __need_size_t
  19. #include <stddef.h>
  20. /* Collect various system dependent definitions and declarations. */
  21. #include <bits/dlfcn.h>
  22. #ifdef __USE_GNU
  23. #include <bits/dl_find_object.h>
  24. /* Type for namespace indices. */
  25. typedef long int Lmid_t;
  26. /* Special namespace ID values. */
  27. # define LM_ID_BASE 0 /* Initial namespace. */
  28. # define LM_ID_NEWLM -1 /* For dlmopen: request new namespace. */
  29. #endif
  30. /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT
  31. the run-time address of the symbol called NAME in the next shared
  32. object is returned. The "next" relation is defined by the order
  33. the shared objects were loaded. */
  34. #define RTLD_NEXT ((void *) -1l)
  35. /* If the first argument to `dlsym' or `dlvsym' is set to RTLD_DEFAULT
  36. the run-time address of the symbol called NAME in the global scope
  37. is returned. */
  38. #define RTLD_DEFAULT ((void *) 0)
  39. __BEGIN_DECLS
  40. /* Open the shared object FILE and map it in; return a handle that can be
  41. passed to `dlsym' to get symbol values from it. */
  42. extern void *dlopen (const char *__file, int __mode) __THROWNL;
  43. /* Unmap and close a shared object opened by `dlopen'.
  44. The handle cannot be used again after calling `dlclose'. */
  45. extern int dlclose (void *__handle) __THROWNL __nonnull ((1));
  46. /* Find the run-time address in the shared object HANDLE refers to
  47. of the symbol called NAME. */
  48. extern void *dlsym (void *__restrict __handle,
  49. const char *__restrict __name) __THROW __nonnull ((2));
  50. #ifdef __USE_GNU
  51. /* Like `dlopen', but request object to be allocated in a new namespace. */
  52. extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROWNL;
  53. /* Find the run-time address in the shared object HANDLE refers to
  54. of the symbol called NAME with VERSION. */
  55. extern void *dlvsym (void *__restrict __handle,
  56. const char *__restrict __name,
  57. const char *__restrict __version)
  58. __THROW __nonnull ((2, 3));
  59. #endif
  60. /* When any of the above functions fails, call this function
  61. to return a string describing the error. Each call resets
  62. the error string so that a following call returns null. */
  63. extern char *dlerror (void) __THROW;
  64. #ifdef __USE_GNU
  65. /* Structure containing information about object searched using
  66. `dladdr'. */
  67. typedef struct
  68. {
  69. const char *dli_fname; /* File name of defining object. */
  70. void *dli_fbase; /* Load address of that object. */
  71. const char *dli_sname; /* Name of nearest symbol. */
  72. void *dli_saddr; /* Exact value of nearest symbol. */
  73. } Dl_info;
  74. /* Fill in *INFO with the following information about ADDRESS.
  75. Returns 0 iff no shared object's segments contain that address. */
  76. extern int dladdr (const void *__address, Dl_info *__info)
  77. __THROW __nonnull ((2));
  78. /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS. */
  79. extern int dladdr1 (const void *__address, Dl_info *__info,
  80. void **__extra_info, int __flags) __THROW __nonnull ((2));
  81. /* These are the possible values for the FLAGS argument to `dladdr1'.
  82. This indicates what extra information is stored at *EXTRA_INFO.
  83. It may also be zero, in which case the EXTRA_INFO argument is not used. */
  84. enum
  85. {
  86. /* Matching symbol table entry (const ElfNN_Sym *). */
  87. RTLD_DL_SYMENT = 1,
  88. /* The object containing the address (struct link_map *). */
  89. RTLD_DL_LINKMAP = 2
  90. };
  91. /* Get information about the shared object HANDLE refers to.
  92. REQUEST is from among the values below, and determines the use of ARG.
  93. On success, returns zero. On failure, returns -1 and records an error
  94. message to be fetched with `dlerror'. */
  95. extern int dlinfo (void *__restrict __handle,
  96. int __request, void *__restrict __arg)
  97. __THROW __nonnull ((1, 3));
  98. /* These are the possible values for the REQUEST argument to `dlinfo'. */
  99. enum
  100. {
  101. /* Treat ARG as `lmid_t *'; store namespace ID for HANDLE there. */
  102. RTLD_DI_LMID = 1,
  103. /* Treat ARG as `struct link_map **';
  104. store the `struct link_map *' for HANDLE there. */
  105. RTLD_DI_LINKMAP = 2,
  106. RTLD_DI_CONFIGADDR = 3, /* Unsupported, defined by Solaris. */
  107. /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the
  108. directories that will be searched for dependencies of this object.
  109. RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size'
  110. entries to indicate the size of the buffer that must be passed to
  111. RTLD_DI_SERINFO to fill in the full information. */
  112. RTLD_DI_SERINFO = 4,
  113. RTLD_DI_SERINFOSIZE = 5,
  114. /* Treat ARG as `char *', and store there the directory name used to
  115. expand $ORIGIN in this shared object's dependency file names. */
  116. RTLD_DI_ORIGIN = 6,
  117. RTLD_DI_PROFILENAME = 7, /* Unsupported, defined by Solaris. */
  118. RTLD_DI_PROFILEOUT = 8, /* Unsupported, defined by Solaris. */
  119. /* Treat ARG as `size_t *', and store there the TLS module ID
  120. of this object's PT_TLS segment, as used in TLS relocations;
  121. store zero if this object does not define a PT_TLS segment. */
  122. RTLD_DI_TLS_MODID = 9,
  123. /* Treat ARG as `void **', and store there a pointer to the calling
  124. thread's TLS block corresponding to this object's PT_TLS segment.
  125. Store a null pointer if this object does not define a PT_TLS
  126. segment, or if the calling thread has not allocated a block for it. */
  127. RTLD_DI_TLS_DATA = 10,
  128. /* Treat ARG as const ElfW(Phdr) **, and store the address of the
  129. program header array at that location. The dlinfo call returns
  130. the number of program headers in the array. */
  131. RTLD_DI_PHDR = 11,
  132. RTLD_DI_MAX = 11
  133. };
  134. /* This is the type of elements in `Dl_serinfo', below.
  135. The `dls_name' member points to space in the buffer passed to `dlinfo'. */
  136. typedef struct
  137. {
  138. char *dls_name; /* Name of library search path directory. */
  139. unsigned int dls_flags; /* Indicates where this directory came from. */
  140. } Dl_serpath;
  141. /* This is the structure that must be passed (by reference) to `dlinfo' for
  142. the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests. */
  143. typedef struct
  144. {
  145. size_t dls_size; /* Size in bytes of the whole buffer. */
  146. unsigned int dls_cnt; /* Number of elements in `dls_serpath'. */
  147. # if __GNUC_PREREQ (3, 0)
  148. /* The zero-length array avoids an unwanted array subscript check by
  149. the compiler, while the surrounding anonymous union preserves the
  150. historic size of the type. At the time of writing, GNU C does
  151. not support structs with flexible array members in unions. */
  152. __extension__ union
  153. {
  154. Dl_serpath dls_serpath[0]; /* Actually longer, dls_cnt elements. */
  155. Dl_serpath __dls_serpath_pad[1];
  156. };
  157. # else
  158. Dl_serpath dls_serpath[1]; /* Actually longer, dls_cnt elements. */
  159. # endif
  160. } Dl_serinfo;
  161. struct dl_find_object
  162. {
  163. __extension__ unsigned long long int dlfo_flags;
  164. void *dlfo_map_start; /* Beginning of mapping containing address. */
  165. void *dlfo_map_end; /* End of mapping. */
  166. struct link_map *dlfo_link_map;
  167. void *dlfo_eh_frame; /* Exception handling data of the object. */
  168. # if DLFO_STRUCT_HAS_EH_DBASE
  169. void *dlfo_eh_dbase; /* Base address for DW_EH_PE_datarel. */
  170. # if __WORDSIZE == 32
  171. unsigned int __dlfo_eh_dbase_pad;
  172. # endif
  173. # endif
  174. # if DLFO_STRUCT_HAS_EH_COUNT
  175. int dlfo_eh_count; /* Number of exception handling entries. */
  176. unsigned int __dlfo_eh_count_pad;
  177. # endif
  178. void *dlfo_sframe; /* SFrame stack trace data of the object. */
  179. #if __WORDSIZE == 32
  180. unsigned int __dlfo_sframe_pad;
  181. #endif
  182. __extension__ unsigned long long int __dlfo_reserved[6];
  183. };
  184. /* If ADDRESS is found in an object, fill in *RESULT and return 0.
  185. Otherwise, return -1. */
  186. int _dl_find_object (void *__address, struct dl_find_object *__result) __THROW;
  187. /* SFrame stack trace data is valid. */
  188. #define DLFO_FLAG_SFRAME (1ULL << 0)
  189. #endif /* __USE_GNU */
  190. __END_DECLS
  191. #endif /* dlfcn.h */