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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * MT safe
  20  */
  21
  22 /* because we are compatible with archive format only since AIX 4.3 */
  23
  24 #define __AR_BIG__
  25
  26 #include "config.h"
  27
  28 #include <ar.h>
  29 #include <stdlib.h>
  30
  31 #include <dlfcn.h>
  32
  33 /* --- functions --- */
  34 static gchar*
  35 fetch_dlerror (gboolean replace_null)
  36 {
  37   gchar *msg = dlerror ();
  38
  39   /* make sure we always return an error message != NULL, if
  40    * expected to do so. */
  41
  42   if (!msg && replace_null)
  43     return "unknown dl-error";
  44
  45   return msg;
  46 }
  47
  48 static gchar* _g_module_get_member(const gchar* file_name)
  49 {
  50   gchar* member = NULL;
  51   struct fl_hdr file_header;
  52   struct ar_hdr ar_header;
  53   long first_member;
  54   long name_len;
  55   int fd;
  56
  57   fd = open(file_name, O_RDONLY);
  58   if (fd == -1)
  59     return NULL;
  60
  61   if (read(fd, (void*)&file_header, FL_HSZ) != FL_HSZ)
  62     goto exit;
  63
  64   if (strncmp(file_header.fl_magic, AIAMAGBIG, SAIAMAG) != 0)
  65     goto exit;
  66
  67   /* read first archive file member header */
  68
  69   first_member = atol(file_header.fl_fstmoff);
  70
  71   if (lseek(fd, first_member, SEEK_SET) != first_member)
  72     goto exit;
  73
  74   if (read(fd, (void*)&ar_header, AR_HSZ - 2) != AR_HSZ - 2)
  75     goto exit;
  76
  77   /* read member name */
  78
  79   name_len = atol(ar_header.ar_namlen);
  80
  81   member = g_malloc(name_len+1);
  82   if (!member)
  83     goto exit;
  84
  85   if (read(fd, (void*)member, name_len) != name_len)
  86     {
  87       g_free(member);
  88       member = NULL;
  89       goto exit;
  90     }
  91
  92   member[name_len] = 0;
  93
  94 exit:
  95   close(fd);
  96
  97   return member;
  98 }
  99
 100 static gpointer
 101 _g_module_open (const gchar *file_name,
 102                 gboolean     bind_lazy,
 103                 gboolean     bind_local)
 104 {
 105   gpointer handle;
 106   gchar* member;
 107   gchar* full_name;
 108
 109   /* extract name of first member of archive */
 110
 111   member = _g_module_get_member (file_name);
 112   if (member != NULL)
 113     {
 114       full_name = g_strconcat (file_name, "(", member, ")", NULL);
 115       g_free (member);
 116     }
 117   else
 118     full_name = g_strdup (file_name);
 119
 120   handle = dlopen (full_name,
 121                    (bind_local ? RTLD_LOCAL : RTLD_GLOBAL) | RTLD_MEMBER | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
 122
 123   g_free (full_name);
 124
 125   if (!handle)
 126     g_module_set_error (fetch_dlerror (TRUE));
 127
 128   return handle;
 129 }
 130
 131 static gpointer
 132 _g_module_self (void)
 133 {
 134   gpointer handle;
 135
 136   handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
 137   if (!handle)
 138     g_module_set_error (fetch_dlerror (TRUE));
 139
 140   return handle;
 141 }
 142
 143 static void
 144 _g_module_close (gpointer handle,
 145                  gboolean is_unref)
 146 {
 147   /* are there any systems out there that have dlopen()/dlclose()
 148    * without a reference count implementation?
 149    */
 150   is_unref |= 1;
 151
 152   if (is_unref)
 153     {
 154       if (dlclose (handle) != 0)
 155         g_module_set_error (fetch_dlerror (TRUE));
 156     }
 157 }
 158
 159 static gpointer
 160 _g_module_symbol (gpointer     handle,
 161                   const gchar *symbol_name)
 162 {
 163   gpointer p;
 164
 165   p = dlsym (handle, symbol_name);
 166   if (!p)
 167     g_module_set_error (fetch_dlerror (FALSE));
 168
 169   return p;
 170 }
 171
 172 static gchar*
 173 _g_module_build_path (const gchar *directory,
 174                       const gchar *module_name)
 175 {
 176   if (directory && *directory) {
 177     if (strncmp (module_name, "lib", 3) == 0)
 178       return g_strconcat (directory, "/", module_name, NULL);
 179     else
 180       return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
 181   } else if (strncmp (module_name, "lib", 3) == 0)
 182     return g_strdup (module_name);
 183   else
 184     return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
 185 }