dlfcn/dlfcn.h

   1 /* User functions for run-time dynamic loading.
   2    Copyright (C) 1995-2001,2003,2004,2006,2009,2012
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  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
  43
  44 /* Type for namespace indeces.  */
  45 typedef long int Lmid_t;
  46
  47 /* Special namespace ID values.  */
  48 # define LM_ID_BASE     0       /* Initial namespace.  */
  49 # define LM_ID_NEWLM    -1      /* For dlmopen: request new namespace.  */
  50 #endif
  51
  52
  53 __BEGIN_DECLS
  54
  55 /* Open the shared object FILE and map it in; return a handle that can be
  56    passed to `dlsym' to get symbol values from it.  */
  57 extern void *dlopen (const char *__file, int __mode) __THROW;
  58
  59 /* Unmap and close a shared object opened by `dlopen'.
  60    The handle cannot be used again after calling `dlclose'.  */
  61 extern int dlclose (void *__handle) __THROW __nonnull ((1));
  62
  63 /* Find the run-time address in the shared object HANDLE refers to
  64    of the symbol called NAME.  */
  65 extern void *dlsym (void *__restrict __handle,
  66                     const char *__restrict __name) __THROW __nonnull ((2));
  67
  68 #ifdef __USE_GNU
  69 /* Like `dlopen', but request object to be allocated in a new namespace.  */
  70 extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROW;
  71
  72 /* Find the run-time address in the shared object HANDLE refers to
  73    of the symbol called NAME with VERSION.  */
  74 extern void *dlvsym (void *__restrict __handle,
  75                      const char *__restrict __name,
  76                      const char *__restrict __version)
  77      __THROW __nonnull ((2, 3));
  78 #endif
  79
  80 /* When any of the above functions fails, call this function
  81    to return a string describing the error.  Each call resets
  82    the error string so that a following call returns null.  */
  83 extern char *dlerror (void) __THROW;
  84
  85
  86 #ifdef __USE_GNU
  87 /* Structure containing information about object searched using
  88    `dladdr'.  */
  89 typedef struct
  90 {
  91   const char *dli_fname;        /* File name of defining object.  */
  92   void *dli_fbase;              /* Load address of that object.  */
  93   const char *dli_sname;        /* Name of nearest symbol.  */
  94   void *dli_saddr;              /* Exact value of nearest symbol.  */
  95 } Dl_info;
  96
  97 /* Fill in *INFO with the following information about ADDRESS.
  98    Returns 0 iff no shared object's segments contain that address.  */
  99 extern int dladdr (const void *__address, Dl_info *__info)
 100      __THROW __nonnull ((2));
 101
 102 /* Same as `dladdr', but additionally sets *EXTRA_INFO according to FLAGS.  */
 103 extern int dladdr1 (const void *__address, Dl_info *__info,
 104                     void **__extra_info, int __flags) __THROW __nonnull ((2));
 105
 106 /* These are the possible values for the FLAGS argument to `dladdr1'.
 107    This indicates what extra information is stored at *EXTRA_INFO.
 108    It may also be zero, in which case the EXTRA_INFO argument is not used.  */
 109 enum
 110   {
 111     /* Matching symbol table entry (const ElfNN_Sym *).  */
 112     RTLD_DL_SYMENT = 1,
 113
 114     /* The object containing the address (struct link_map *).  */
 115     RTLD_DL_LINKMAP = 2
 116   };
 117
 118
 119 /* Get information about the shared object HANDLE refers to.
 120    REQUEST is from among the values below, and determines the use of ARG.
 121
 122    On success, returns zero.  On failure, returns -1 and records an error
 123    message to be fetched with `dlerror'.  */
 124 extern int dlinfo (void *__restrict __handle,
 125                    int __request, void *__restrict __arg)
 126      __THROW __nonnull ((1, 3));
 127
 128 /* These are the possible values for the REQUEST argument to `dlinfo'.  */
 129 enum
 130   {
 131     /* Treat ARG as `lmid_t *'; store namespace ID for HANDLE there.  */
 132     RTLD_DI_LMID = 1,
 133
 134     /* Treat ARG as `struct link_map **';
 135        store the `struct link_map *' for HANDLE there.  */
 136     RTLD_DI_LINKMAP = 2,
 137
 138     RTLD_DI_CONFIGADDR = 3,     /* Unsupported, defined by Solaris.  */
 139
 140     /* Treat ARG as `Dl_serinfo *' (see below), and fill in to describe the
 141        directories that will be searched for dependencies of this object.
 142        RTLD_DI_SERINFOSIZE fills in just the `dls_cnt' and `dls_size'
 143        entries to indicate the size of the buffer that must be passed to
 144        RTLD_DI_SERINFO to fill in the full information.  */
 145     RTLD_DI_SERINFO = 4,
 146     RTLD_DI_SERINFOSIZE = 5,
 147
 148     /* Treat ARG as `char *', and store there the directory name used to
 149        expand $ORIGIN in this shared object's dependency file names.  */
 150     RTLD_DI_ORIGIN = 6,
 151
 152     RTLD_DI_PROFILENAME = 7,    /* Unsupported, defined by Solaris.  */
 153     RTLD_DI_PROFILEOUT = 8,     /* Unsupported, defined by Solaris.  */
 154
 155     /* Treat ARG as `size_t *', and store there the TLS module ID
 156        of this object's PT_TLS segment, as used in TLS relocations;
 157        store zero if this object does not define a PT_TLS segment.  */
 158     RTLD_DI_TLS_MODID = 9,
 159
 160     /* Treat ARG as `void **', and store there a pointer to the calling
 161        thread's TLS block corresponding to this object's PT_TLS segment.
 162        Store a null pointer if this object does not define a PT_TLS
 163        segment, or if the calling thread has not allocated a block for it.  */
 164     RTLD_DI_TLS_DATA = 10,
 165
 166     RTLD_DI_MAX = 10
 167   };
 168
 169
 170 /* This is the type of elements in `Dl_serinfo', below.
 171    The `dls_name' member points to space in the buffer passed to `dlinfo'.  */
 172 typedef struct
 173 {
 174   char *dls_name;               /* Name of library search path directory.  */
 175   unsigned int dls_flags;       /* Indicates where this directory came from. */
 176 } Dl_serpath;
 177
 178 /* This is the structure that must be passed (by reference) to `dlinfo' for
 179    the RTLD_DI_SERINFO and RTLD_DI_SERINFOSIZE requests.  */
 180 typedef struct
 181 {
 182   size_t dls_size;              /* Size in bytes of the whole buffer.  */
 183   unsigned int dls_cnt;         /* Number of elements in `dls_serpath'.  */
 184   Dl_serpath dls_serpath[1];    /* Actually longer, dls_cnt elements.  */
 185 } Dl_serinfo;
 186 #endif /* __USE_GNU */
 187
 188
 189 __END_DECLS
 190
 191 #endif  /* dlfcn.h */