dlfcn.h 7.3 KB

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  1. /* User functions for run-time dynamic loading.
  2. Copyright (C) 1995-2020 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. /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT
  24. the run-time address of the symbol called NAME in the next shared
  25. object is returned. The "next" relation is defined by the order
  26. the shared objects were loaded. */
  27. # define RTLD_NEXT ((void *) -1l)
  28. /* If the first argument to `dlsym' or `dlvsym' is set to RTLD_DEFAULT
  29. the run-time address of the symbol called NAME in the global scope
  30. is returned. */
  31. # define RTLD_DEFAULT ((void *) 0)
  32. /* Type for namespace indeces. */
  33. typedef long int Lmid_t;
  34. /* Special namespace ID values. */
  35. # define LM_ID_BASE 0 /* Initial namespace. */
  36. # define LM_ID_NEWLM -1 /* For dlmopen: request new namespace. */
  37. #endif
  38. __BEGIN_DECLS
  39. /* Open the shared object FILE and map it in; return a handle that can be
  40. passed to `dlsym' to get symbol values from it. */
  41. extern void *dlopen (const char *__file, int __mode) __THROWNL;
  42. /* Unmap and close a shared object opened by `dlopen'.
  43. The handle cannot be used again after calling `dlclose'. */
  44. extern int dlclose (void *__handle) __THROWNL __nonnull ((1));
  45. /* Find the run-time address in the shared object HANDLE refers to
  46. of the symbol called NAME. */
  47. extern void *dlsym (void *__restrict __handle,
  48. const char *__restrict __name) __THROW __nonnull ((2));
  49. #ifdef __USE_GNU
  50. /* Like `dlopen', but request object to be allocated in a new namespace. */
  51. extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROWNL;
  52. /* Find the run-time address in the shared object HANDLE refers to
  53. of the symbol called NAME with VERSION. */
  54. extern void *dlvsym (void *__restrict __handle,
  55. const char *__restrict __name,
  56. const char *__restrict __version)
  57. __THROW __nonnull ((2, 3));
  58. #endif
  59. /* When any of the above functions fails, call this function
  60. to return a string describing the error. Each call resets
  61. the error string so that a following call returns null. */
  62. extern char *dlerror (void) __THROW;
  63. #ifdef __USE_GNU
  64. /* Structure containing information about object searched using
  65. `dladdr'. */
  66. typedef struct
  67. {
  68. const char *dli_fname; /* File name of defining object. */
  69. void *dli_fbase; /* Load address of that object. */
  70. const char *dli_sname; /* Name of nearest symbol. */
  71. void *dli_saddr; /* Exact value of nearest symbol. */
  72. } Dl_info;
  73. /* Fill in *INFO with the following information about ADDRESS.
  74. Returns 0 iff no shared object's segments contain that address. */
  75. extern int dladdr (const void *__address, Dl_info *__info)
  76. __THROW __nonnull ((2));
  77. /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS. */
  78. extern int dladdr1 (const void *__address, Dl_info *__info,
  79. void **__extra_info, int __flags) __THROW __nonnull ((2));
  80. /* These are the possible values for the FLAGS argument to `dladdr1'.
  81. This indicates what extra information is stored at *EXTRA_INFO.
  82. It may also be zero, in which case the EXTRA_INFO argument is not used. */
  83. enum
  84. {
  85. /* Matching symbol table entry (const ElfNN_Sym *). */
  86. RTLD_DL_SYMENT = 1,
  87. /* The object containing the address (struct link_map *). */
  88. RTLD_DL_LINKMAP = 2
  89. };
  90. /* Get information about the shared object HANDLE refers to.
  91. REQUEST is from among the values below, and determines the use of ARG.
  92. On success, returns zero. On failure, returns -1 and records an error
  93. message to be fetched with `dlerror'. */
  94. extern int dlinfo (void *__restrict __handle,
  95. int __request, void *__restrict __arg)
  96. __THROW __nonnull ((1, 3));
  97. /* These are the possible values for the REQUEST argument to `dlinfo'. */
  98. enum
  99. {
  100. /* Treat ARG as `lmid_t *'; store namespace ID for HANDLE there. */
  101. RTLD_DI_LMID = 1,
  102. /* Treat ARG as `struct link_map **';
  103. store the `struct link_map *' for HANDLE there. */
  104. RTLD_DI_LINKMAP = 2,
  105. RTLD_DI_CONFIGADDR = 3, /* Unsupported, defined by Solaris. */
  106. /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the
  107. directories that will be searched for dependencies of this object.
  108. RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size'
  109. entries to indicate the size of the buffer that must be passed to
  110. RTLD_DI_SERINFO to fill in the full information. */
  111. RTLD_DI_SERINFO = 4,
  112. RTLD_DI_SERINFOSIZE = 5,
  113. /* Treat ARG as `char *', and store there the directory name used to
  114. expand $ORIGIN in this shared object's dependency file names. */
  115. RTLD_DI_ORIGIN = 6,
  116. RTLD_DI_PROFILENAME = 7, /* Unsupported, defined by Solaris. */
  117. RTLD_DI_PROFILEOUT = 8, /* Unsupported, defined by Solaris. */
  118. /* Treat ARG as `size_t *', and store there the TLS module ID
  119. of this object's PT_TLS segment, as used in TLS relocations;
  120. store zero if this object does not define a PT_TLS segment. */
  121. RTLD_DI_TLS_MODID = 9,
  122. /* Treat ARG as `void **', and store there a pointer to the calling
  123. thread's TLS block corresponding to this object's PT_TLS segment.
  124. Store a null pointer if this object does not define a PT_TLS
  125. segment, or if the calling thread has not allocated a block for it. */
  126. RTLD_DI_TLS_DATA = 10,
  127. RTLD_DI_MAX = 10
  128. };
  129. /* This is the type of elements in `Dl_serinfo', below.
  130. The `dls_name' member points to space in the buffer passed to `dlinfo'. */
  131. typedef struct
  132. {
  133. char *dls_name; /* Name of library search path directory. */
  134. unsigned int dls_flags; /* Indicates where this directory came from. */
  135. } Dl_serpath;
  136. /* This is the structure that must be passed (by reference) to `dlinfo' for
  137. the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests. */
  138. typedef struct
  139. {
  140. size_t dls_size; /* Size in bytes of the whole buffer. */
  141. unsigned int dls_cnt; /* Number of elements in `dls_serpath'. */
  142. # if __GNUC_PREREQ (3, 0)
  143. /* The zero-length array avoids an unwanted array subscript check by
  144. the compiler, while the surrounding anonymous union preserves the
  145. historic size of the type. At the time of writing, GNU C does
  146. not support structs with flexible array members in unions. */
  147. __extension__ union
  148. {
  149. Dl_serpath dls_serpath[0]; /* Actually longer, dls_cnt elements. */
  150. Dl_serpath __dls_serpath_pad[1];
  151. };
  152. # else
  153. Dl_serpath dls_serpath[1]; /* Actually longer, dls_cnt elements. */
  154. # endif
  155. } Dl_serinfo;
  156. #endif /* __USE_GNU */
  157. __END_DECLS
  158. #endif /* dlfcn.h */