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 #include <ar.h>
  28 #include <stdlib.h>
  29
  30 #include <dlfcn.h>
  31
  32 /* --- functions --- */
  33 static gchar*
  34 fetch_dlerror (gboolean replace_null)
  35 {
  36   gchar *msg = dlerror ();
  37
  38   /* make sure we always return an error message != NULL, if
  39    * expected to do so. */
  40
  41   if (!msg && replace_null)
  42     return "unknown dl-error";
  43
  44   return msg;
  45 }
  46
  47 static gchar* _g_module_get_member(const gchar* file_name)
  48 {
  49   gchar* member = NULL;
  50   struct fl_hdr file_header;
  51   struct ar_hdr ar_header;
  52   long first_member;
  53   long name_len;
  54   int fd;
  55
  56   fd = open(file_name, O_RDONLY);
  57   if (fd == -1)
  58     return NULL;
  59
  60   if (read(fd, (void*)&file_header, FL_HSZ) != FL_HSZ)
  61     goto exit;
  62
  63   if (strncmp(file_header.fl_magic, AIAMAGBIG, SAIAMAG) != 0)
  64     goto exit;
  65
  66   /* read first archive file member header */
  67
  68   first_member = atol(file_header.fl_fstmoff);
  69
  70   if (lseek(fd, first_member, SEEK_SET) != first_member)
  71     goto exit;
  72
  73   if (read(fd, (void*)&ar_header, AR_HSZ - 2) != AR_HSZ - 2)
  74     goto exit;
  75
  76   /* read member name */
  77
  78   name_len = atol(ar_header.ar_namlen);
  79
  80   member = g_malloc(name_len+1);
  81   if (!member)
  82     goto exit;
  83
  84   if (read(fd, (void*)member, name_len) != name_len)
  85     {
  86       g_free(member);
  87       member = NULL;
  88       goto exit;
  89     }
  90
  91   member[name_len] = 0;
  92
  93 exit:
  94   close(fd);
  95
  96   return member;
  97 }
  98
  99 static gpointer
 100 _g_module_open (const gchar *file_name,
 101                 gboolean     bind_lazy,
 102                 gboolean     bind_local)
 103 {
 104   gpointer handle;
 105   gchar* member;
 106   gchar* full_name;
 107
 108   /* extract name of first member of archive */
 109
 110   member = _g_module_get_member (file_name);
 111   if (member != NULL)
 112     {
 113       full_name = g_strconcat (file_name, "(", member, ")", NULL);
 114       g_free (member);
 115     }
 116   else
 117     full_name = g_strdup (file_name);
 118
 119   handle = dlopen (full_name,
 120                    (bind_local ? RTLD_LOCAL : RTLD_GLOBAL) | RTLD_MEMBER | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
 121
 122   g_free (full_name);
 123
 124   if (!handle)
 125     g_module_set_error (fetch_dlerror (TRUE));
 126
 127   return handle;
 128 }
 129
 130 static gpointer
 131 _g_module_self (void)
 132 {
 133   gpointer handle;
 134
 135   handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
 136   if (!handle)
 137     g_module_set_error (fetch_dlerror (TRUE));
 138
 139   return handle;
 140 }
 141
 142 static void
 143 _g_module_close (gpointer handle,
 144                  gboolean is_unref)
 145 {
 146   /* are there any systems out there that have dlopen()/dlclose()
 147    * without a reference count implementation?
 148    */
 149   is_unref |= 1;
 150
 151   if (is_unref)
 152     {
 153       if (dlclose (handle) != 0)
 154         g_module_set_error (fetch_dlerror (TRUE));
 155     }
 156 }
 157
 158 static gpointer
 159 _g_module_symbol (gpointer     handle,
 160                   const gchar *symbol_name)
 161 {
 162   gpointer p;
 163
 164   p = dlsym (handle, symbol_name);
 165   if (!p)
 166     g_module_set_error (fetch_dlerror (FALSE));
 167
 168   return p;
 169 }
 170
 171 static gchar*
 172 _g_module_build_path (const gchar *directory,
 173                       const gchar *module_name)
 174 {
 175   if (directory && *directory) {
 176     if (strncmp (module_name, "lib", 3) == 0)
 177       return g_strconcat (directory, "/", module_name, NULL);
 178     else
 179       return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
 180   } else if (strncmp (module_name, "lib", 3) == 0)
 181     return g_strdup (module_name);
 182   else
 183     return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
 184 }