gmodule/gmodule-ar.c

   1 /* GMODULE - GLIB wrapper code for dynamic module loading
   2  * Copyright (C) 1998, 2000 Tim Janik
   3  *
   4  * This 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 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * MT safe
  22  */
  23
  24 /* because we are compatible with archive format only since AIX 4.3 */
  25
  26 #define __AR_BIG__
  27
  28 #include "config.h"
  29
  30 #include <ar.h>
  31 #include <stdlib.h>
  32
  33 #include <dlfcn.h>
  34
  35 /* --- functions --- */
  36 static gchar*
  37 fetch_dlerror (gboolean replace_null)
  38 {
  39   gchar *msg = dlerror ();
  40
  41   /* make sure we always return an error message != NULL, if
  42    * expected to do so. */
  43
  44   if (!msg && replace_null)
  45     return "unknown dl-error";
  46
  47   return msg;
  48 }
  49
  50 static gchar* _g_module_get_member(const gchar* file_name)
  51 {
  52   gchar* member = NULL;
  53   struct fl_hdr file_header;
  54   struct ar_hdr ar_header;
  55   long first_member;
  56   long name_len;
  57   int fd;
  58
  59   fd = open(file_name, O_RDONLY);
  60   if (fd == -1)
  61     return NULL;
  62
  63   if (read(fd, (void*)&file_header, FL_HSZ) != FL_HSZ)
  64     goto exit;
  65
  66   if (strncmp(file_header.fl_magic, AIAMAGBIG, SAIAMAG) != 0)
  67     goto exit;
  68
  69   /* read first archive file member header */
  70
  71   first_member = atol(file_header.fl_fstmoff);
  72
  73   if (lseek(fd, first_member, SEEK_SET) != first_member)
  74     goto exit;
  75
  76   if (read(fd, (void*)&ar_header, AR_HSZ - 2) != AR_HSZ - 2)
  77     goto exit;
  78
  79   /* read member name */
  80
  81   name_len = atol(ar_header.ar_namlen);
  82
  83   member = g_malloc(name_len+1);
  84   if (!member)
  85     goto exit;
  86
  87   if (read(fd, (void*)member, name_len) != name_len)
  88     {
  89       g_free(member);
  90       member = NULL;
  91       goto exit;
  92     }
  93
  94   member[name_len] = 0;
  95
  96 exit:
  97   close(fd);
  98
  99   return member;
 100 }
 101
 102 static gpointer
 103 _g_module_open (const gchar *file_name,
 104                 gboolean     bind_lazy,
 105                 gboolean     bind_local)
 106 {
 107   gpointer handle;
 108   gchar* member;
 109   gchar* full_name;
 110
 111   /* extract name of first member of archive */
 112
 113   member = _g_module_get_member (file_name);
 114   if (member != NULL)
 115     {
 116       full_name = g_strconcat (file_name, "(", member, ")", NULL);
 117       g_free (member);
 118     }
 119   else
 120     full_name = g_strdup (file_name);
 121
 122   handle = dlopen (full_name,
 123                    (bind_local ? RTLD_LOCAL : RTLD_GLOBAL) | RTLD_MEMBER | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
 124
 125   g_free (full_name);
 126
 127   if (!handle)
 128     g_module_set_error (fetch_dlerror (TRUE));
 129
 130   return handle;
 131 }
 132
 133 static gpointer
 134 _g_module_self (void)
 135 {
 136   gpointer handle;
 137
 138   handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
 139   if (!handle)
 140     g_module_set_error (fetch_dlerror (TRUE));
 141
 142   return handle;
 143 }
 144
 145 static void
 146 _g_module_close (gpointer handle,
 147                  gboolean is_unref)
 148 {
 149   /* are there any systems out there that have dlopen()/dlclose()
 150    * without a reference count implementation?
 151    */
 152   is_unref |= 1;
 153
 154   if (is_unref)
 155     {
 156       if (dlclose (handle) != 0)
 157         g_module_set_error (fetch_dlerror (TRUE));
 158     }
 159 }
 160
 161 static gpointer
 162 _g_module_symbol (gpointer     handle,
 163                   const gchar *symbol_name)
 164 {
 165   gpointer p;
 166
 167   p = dlsym (handle, symbol_name);
 168   if (!p)
 169     g_module_set_error (fetch_dlerror (FALSE));
 170
 171   return p;
 172 }
 173
 174 static gchar*
 175 _g_module_build_path (const gchar *directory,
 176                       const gchar *module_name)
 177 {
 178   if (directory && *directory) {
 179     if (strncmp (module_name, "lib", 3) == 0)
 180       return g_strconcat (directory, "/", module_name, NULL);
 181     else
 182       return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
 183   } else if (strncmp (module_name, "lib", 3) == 0)
 184     return g_strdup (module_name);
 185   else
 186     return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
 187 }