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 extern void *dlopen (__const char *__file, int __mode) __THROW;
  50
  51 /* Unmap and close a shared object opened by `dlopen'.
  52    The handle cannot be used again after calling `dlclose'.  */
  53 extern int dlclose (void *__handle) __THROW;
  54
  55 /* Find the run-time address in the shared object HANDLE refers to
  56    of the symbol called NAME.  */
  57 extern void *dlsym (void *__restrict __handle,
  58                     __const char *__restrict __name) __THROW;
  59
  60 #ifdef __USE_GNU
  61 /* Find the run-time address in the shared object HANDLE refers to
  62    of the symbol called NAME with VERSION.  */
  63 extern void *dlvsym (void *__restrict __handle,
  64                      __const char *__restrict __name,
  65                      __const char *__restrict __version) __THROW;
  66 #endif
  67
  68 /* When any of the above functions fails, call this function
  69    to return a string describing the error.  Each call resets
  70    the error string so that a following call returns null.  */
  71 extern char *dlerror (void) __THROW;
  72
  73
  74 #ifdef __USE_GNU
  75 /* Structure containing information about object searched using
  76    `dladdr'.  */
  77 typedef struct
  78 {
  79   __const char *dli_fname;      /* File name of defining object.  */
  80   void *dli_fbase;              /* Load address of that object.  */
  81   __const char *dli_sname;      /* Name of nearest symbol.  */
  82   void *dli_saddr;              /* Exact value of nearest symbol.  */
  83 } Dl_info;
  84
  85 /* Fill in *INFO with the following information about ADDRESS.
  86    Returns 0 iff no shared object's segments contain that address.  */
  87 extern int dladdr (__const void *__address, Dl_info *__info) __THROW;
  88
  89 /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS.  */
  90 extern int dladdr1 (__const void *__address, Dl_info *__info,
  91                     void **__extra_info, int __flags) __THROW;
  92
  93 /* These are the possible values for the FLAGS argument to `dladdr1'.
  94    This indicates what extra information is stored at *EXTRA_INFO.
  95    It may also be zero, in which case the EXTRA_INFO argument is not used.  */
  96 enum
  97   {
  98     /* Matching symbol table entry (const ElfNN_Sym *).  */
  99     RTLD_DL_SYMENT = 1,
 100
 101     /* The object containing the address (struct link_map *).  */
 102     RTLD_DL_LINKMAP = 2
 103   };
 104
 105
 106 /* Get information about the shared object HANDLE refers to.
 107    REQUEST is from among the values below, and determines the use of ARG.
 108
 109    On success, returns zero.  On failure, returns -1 and records an error
 110    message to be fetched with `dlerror'.  */
 111 extern int dlinfo (void *__restrict __handle,
 112                    int __request, void *__restrict __arg);
 113
 114 /* These are the possible values for the REQUEST argument to `dlinfo'.  */
 115 enum
 116   {
 117     /* Treat ARG as `struct link_map **';
 118        store the `struct link_map *' for HANDLE there.  */
 119     RTLD_DI_LINKMAP = 2,
 120
 121     /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the
 122        directories that will be searched for dependencies of this object.
 123        RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size'
 124        entries to indicate the size of the buffer that must be passed to
 125        RTLD_DI_SERINFO to fill in the full information.  */
 126     RTLD_DI_SERINFO = 4,
 127     RTLD_DI_SERINFOSIZE = 5,
 128
 129     /* Treat ARG as `char *', and store there the directory name used to
 130        expand $ORIGIN in this shared object's dependency file names.  */
 131     RTLD_DI_ORIGIN = 6,
 132
 133     RTLD_DI_LMID = 1,           /* Unsupported, defined by Solaris.  */
 134     RTLD_DI_CONFIGADDR = 3      /* Unsupported, defined by Solaris.  */
 135   };
 136
 137
 138 /* This is the type of elements in `Dl_serinfo', below.
 139    The `dls_name' member points to space in the buffer passed to `dlinfo'.  */
 140 typedef struct
 141 {
 142   char *dls_name;               /* Name of library search path directory.  */
 143   unsigned int dls_flags;       /* Indicates where this directory came from. */
 144 } Dl_serpath;
 145
 146 /* This is the structure that must be passed (by reference) to `dlinfo' for
 147    the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests.  */
 148 typedef struct
 149 {
 150   size_t dls_size;              /* Size in bytes of the whole buffer.  */
 151   unsigned int dls_cnt;         /* Number of elements in `dls_serpath'.  */
 152   Dl_serpath dls_serpath[1];    /* Actually longer, dls_cnt elements.  */
 153 } Dl_serinfo;
 154 #endif /* __USE_GNU */
 155
 156
 157 __END_DECLS
 158
 159 #endif  /* dlfcn.h */