dlfcn/dlfcn.h

   1 /* User functions for run-time dynamic loading.
   2    Copyright (C) 1995-1999,2000,2001,2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _DLFCN_H
  21 #define _DLFCN_H 1
  22
  23 #include <features.h>
  24 #define __need_size_t
  25 #include <stddef.h>
  26
  27 /* Collect various system dependent definitions and declarations.  */
  28 #include <bits/dlfcn.h>
  29
  30
  31 #ifdef __USE_GNU
  32 /* If the first argument of `dlsym' or `dlvsym' is set to RTLD_NEXT
  33    the run-time address of the symbol called NAME in the next shared
  34    object is returned.  The "next" relation is defined by the order
  35    the shared objects were loaded.  */
  36 # define RTLD_NEXT      ((void *) -1l)
  37
  38 /* If the first argument to `dlsym' or `dlvsym' is set to RTLD_DEFAULT
  39    the run-time address of the symbol called NAME in the global scope
  40    is returned.  */
  41 # define RTLD_DEFAULT   ((void *) 0)
  42 #endif
  43
  44
  45 __BEGIN_DECLS
  46
  47 /* Open the shared object FILE and map it in; return a handle that can be
  48    passed to `dlsym' to get symbol values from it.
  49
  50    This function is a possible cancellation point and therefore not
  51    marked with __THROW.  */
  52 extern void *dlopen (__const char *__file, int __mode);
  53
  54 /* Unmap and close a shared object opened by `dlopen'.
  55    The handle cannot be used again after calling `dlclose'.  */
  56 extern int dlclose (void *__handle) __THROW;
  57
  58 /* Find the run-time address in the shared object HANDLE refers to
  59    of the symbol called NAME.  */
  60 extern void *dlsym (void *__restrict __handle,
  61                     __const char *__restrict __name) __THROW;
  62
  63 #ifdef __USE_GNU
  64 /* Find the run-time address in the shared object HANDLE refers to
  65    of the symbol called NAME with VERSION.  */
  66 extern void *dlvsym (void *__restrict __handle,
  67                      __const char *__restrict __name,
  68                      __const char *__restrict __version) __THROW;
  69 #endif
  70
  71 /* When any of the above functions fails, call this function
  72    to return a string describing the error.  Each call resets
  73    the error string so that a following call returns null.  */
  74 extern char *dlerror (void) __THROW;
  75
  76
  77 #ifdef __USE_GNU
  78 /* Structure containing information about object searched using
  79    `dladdr'.  */
  80 typedef struct
  81 {
  82   __const char *dli_fname;      /* File name of defining object.  */
  83   void *dli_fbase;              /* Load address of that object.  */
  84   __const char *dli_sname;      /* Name of nearest symbol.  */
  85   void *dli_saddr;              /* Exact value of nearest symbol.  */
  86 } Dl_info;
  87
  88 /* Fill in *INFO with the following information about ADDRESS.
  89    Returns 0 iff no shared object's segments contain that address.  */
  90 extern int dladdr (__const void *__address, Dl_info *__info) __THROW;
  91
  92 /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS.  */
  93 extern int dladdr1 (__const void *__address, Dl_info *__info,
  94                     void **__extra_info, int __flags) __THROW;
  95
  96 /* These are the possible values for the FLAGS argument to `dladdr1'.
  97    This indicates what extra information is stored at *EXTRA_INFO.
  98    It may also be zero, in which case the EXTRA_INFO argument is not used.  */
  99 enum
 100   {
 101     /* Matching symbol table entry (const ElfNN_Sym *).  */
 102     RTLD_DL_SYMENT = 1,
 103
 104     /* The object containing the address (struct link_map *).  */
 105     RTLD_DL_LINKMAP = 2
 106   };
 107
 108
 109 /* Get information about the shared object HANDLE refers to.
 110    REQUEST is from among the values below, and determines the use of ARG.
 111
 112    On success, returns zero.  On failure, returns -1 and records an error
 113    message to be fetched with `dlerror'.  */
 114 extern int dlinfo (void *__restrict __handle,
 115                    int __request, void *__restrict __arg);
 116
 117 /* These are the possible values for the REQUEST argument to `dlinfo'.  */
 118 enum
 119   {
 120     /* Treat ARG as `struct link_map **';
 121        store the `struct link_map *' for HANDLE there.  */
 122     RTLD_DI_LINKMAP = 2,
 123
 124     /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the
 125        directories that will be searched for dependencies of this object.
 126        RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size'
 127        entries to indicate the size of the buffer that must be passed to
 128        RTLD_DI_SERINFO to fill in the full information.  */
 129     RTLD_DI_SERINFO = 4,
 130     RTLD_DI_SERINFOSIZE = 5,
 131
 132     /* Treat ARG as `char *', and store there the directory name used to
 133        expand $ORIGIN in this shared object's dependency file names.  */
 134     RTLD_DI_ORIGIN = 6,
 135
 136     RTLD_DI_LMID = 1,           /* Unsupported, defined by Solaris.  */
 137     RTLD_DI_CONFIGADDR = 3      /* Unsupported, defined by Solaris.  */
 138   };
 139
 140
 141 /* This is the type of elements in `Dl_serinfo', below.
 142    The `dls_name' member points to space in the buffer passed to `dlinfo'.  */
 143 typedef struct
 144 {
 145   char *dls_name;               /* Name of library search path directory.  */
 146   unsigned int dls_flags;       /* Indicates where this directory came from. */
 147 } Dl_serpath;
 148
 149 /* This is the structure that must be passed (by reference) to `dlinfo' for
 150    the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests.  */
 151 typedef struct
 152 {
 153   size_t dls_size;              /* Size in bytes of the whole buffer.  */
 154   unsigned int dls_cnt;         /* Number of elements in `dls_serpath'.  */
 155   Dl_serpath dls_serpath[1];    /* Actually longer, dls_cnt elements.  */
 156 } Dl_serinfo;
 157 #endif /* __USE_GNU */
 158
 159
 160 __END_DECLS
 161
 162 #endif  /* dlfcn.h */