root/source4/heimdal/lib/krb5/plugin.c

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DEFINITIONS

This source file includes following definitions.
  1. _krb5_plugin_get_symbol
  2. _krb5_plugin_get_next
  3. loadlib
  4. krb5_plugin_register
  5. _krb5_plugin_find
  6. _krb5_plugin_free

   1 /*
   2  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33 
  34 #include "krb5_locl.h"
  35 RCSID("$Id$");
  36 #ifdef HAVE_DLFCN_H
  37 #include <dlfcn.h>
  38 #endif
  39 #include <dirent.h>
  40 
  41 struct krb5_plugin {
  42     void *symbol;
  43     void *dsohandle;
  44     struct krb5_plugin *next;
  45 };
  46 
  47 struct plugin {
  48     enum krb5_plugin_type type;
  49     void *name;
  50     void *symbol;
  51     struct plugin *next;
  52 };
  53 
  54 static HEIMDAL_MUTEX plugin_mutex = HEIMDAL_MUTEX_INITIALIZER;
  55 static struct plugin *registered = NULL;
  56 
  57 static const char *plugin_dir = LIBDIR "/plugin/krb5";
  58 
  59 /*
  60  *
  61  */
  62 
  63 void *
  64 _krb5_plugin_get_symbol(struct krb5_plugin *p)
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  65 {
  66     return p->symbol;
  67 }
  68 
  69 struct krb5_plugin *
  70 _krb5_plugin_get_next(struct krb5_plugin *p)
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  71 {
  72     return p->next;
  73 }
  74 
  75 /*
  76  *
  77  */
  78 
  79 #ifdef HAVE_DLOPEN
  80 
  81 static krb5_error_code
  82 loadlib(krb5_context context,
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  83         enum krb5_plugin_type type,
  84         const char *name,
  85         const char *lib,
  86         struct krb5_plugin **e)
  87 {
  88     *e = calloc(1, sizeof(**e));
  89     if (*e == NULL) {
  90         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  91         return ENOMEM;
  92     }
  93 
  94 #ifndef RTLD_LAZY
  95 #define RTLD_LAZY 0
  96 #endif
  97 
  98     (*e)->dsohandle = dlopen(lib, RTLD_LAZY);
  99     if ((*e)->dsohandle == NULL) {
 100         free(*e);
 101         *e = NULL;
 102         krb5_set_error_message(context, ENOMEM, "Failed to load %s: %s",
 103                                lib, dlerror());
 104         return ENOMEM;
 105     }
 106 
 107     /* dlsym doesn't care about the type */
 108     (*e)->symbol = dlsym((*e)->dsohandle, name);
 109     if ((*e)->symbol == NULL) {
 110         dlclose((*e)->dsohandle);
 111         free(*e);
 112         krb5_clear_error_message(context);
 113         return ENOMEM;
 114     }
 115 
 116     return 0;
 117 }
 118 #endif /* HAVE_DLOPEN */
 119 
 120 /**
 121  * Register a plugin symbol name of specific type.
 122  * @param context a Keberos context
 123  * @param type type of plugin symbol
 124  * @param name name of plugin symbol
 125  * @param symbol a pointer to the named symbol
 126  * @return In case of error a non zero error com_err error is returned
 127  * and the Kerberos error string is set.
 128  *
 129  * @ingroup krb5_support
 130  */
 131 
 132 krb5_error_code
 133 krb5_plugin_register(krb5_context context,
     /* [<][>][^][v][top][bottom][index][help] */
 134                      enum krb5_plugin_type type,
 135                      const char *name,
 136                      void *symbol)
 137 {
 138     struct plugin *e;
 139 
 140     /* check for duplicates */
 141     for (e = registered; e != NULL; e = e->next)
 142         if (e->type == type && strcmp(e->name,name)== 0 && e->symbol == symbol)
 143             return 0;
 144 
 145     e = calloc(1, sizeof(*e));
 146     if (e == NULL) {
 147         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 148         return ENOMEM;
 149     }
 150     e->type = type;
 151     e->name = strdup(name);
 152     if (e->name == NULL) {
 153         free(e);
 154         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 155         return ENOMEM;
 156     }
 157     e->symbol = symbol;
 158 
 159     HEIMDAL_MUTEX_lock(&plugin_mutex);
 160     e->next = registered;
 161     registered = e;
 162     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 163 
 164     return 0;
 165 }
 166 
 167 krb5_error_code
 168 _krb5_plugin_find(krb5_context context,
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 169                   enum krb5_plugin_type type,
 170                   const char *name,
 171                   struct krb5_plugin **list)
 172 {
 173     struct krb5_plugin *e;
 174     struct plugin *p;
 175     krb5_error_code ret;
 176     char *sysdirs[2] = { NULL, NULL };
 177     char **dirs = NULL, **di;
 178     struct dirent *entry;
 179     char *path;
 180     DIR *d = NULL;
 181 
 182     *list = NULL;
 183 
 184     HEIMDAL_MUTEX_lock(&plugin_mutex);
 185 
 186     for (p = registered; p != NULL; p = p->next) {
 187         if (p->type != type || strcmp(p->name, name) != 0)
 188             continue;
 189 
 190         e = calloc(1, sizeof(*e));
 191         if (e == NULL) {
 192             HEIMDAL_MUTEX_unlock(&plugin_mutex);
 193             ret = ENOMEM;
 194             krb5_set_error_message(context, ret, "malloc: out of memory");
 195             goto out;
 196         }
 197         e->symbol = p->symbol;
 198         e->dsohandle = NULL;
 199         e->next = *list;
 200         *list = e;
 201     }
 202     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 203 
 204 #ifdef HAVE_DLOPEN
 205 
 206     dirs = krb5_config_get_strings(context, NULL, "libdefaults",
 207                                    "plugin_dir", NULL);
 208     if (dirs == NULL) {
 209         sysdirs[0] = rk_UNCONST(plugin_dir);
 210         dirs = sysdirs;
 211     }
 212 
 213     for (di = dirs; *di != NULL; di++) {
 214 
 215         d = opendir(*di);
 216         if (d == NULL)
 217             continue;
 218         rk_cloexec(dirfd(d));
 219 
 220         while ((entry = readdir(d)) != NULL) {
 221             asprintf(&path, "%s/%s", *di, entry->d_name);
 222             if (path == NULL) {
 223                 ret = ENOMEM;
 224                 krb5_set_error_message(context, ret, "malloc: out of memory");
 225                 goto out;
 226             }
 227             ret = loadlib(context, type, name, path, &e);
 228             free(path);
 229             if (ret)
 230                 continue;
 231         
 232             e->next = *list;
 233             *list = e;
 234         }
 235         closedir(d);
 236     }
 237     if (dirs != sysdirs)
 238         krb5_config_free_strings(dirs);
 239 #endif /* HAVE_DLOPEN */
 240 
 241     if (*list == NULL) {
 242         krb5_set_error_message(context, ENOENT, "Did not find a plugin for %s", name);
 243         return ENOENT;
 244     }
 245 
 246     return 0;
 247 
 248 out:
 249     if (dirs && dirs != sysdirs)
 250         krb5_config_free_strings(dirs);
 251     if (d)
 252         closedir(d);
 253     _krb5_plugin_free(*list);
 254     *list = NULL;
 255 
 256     return ret;
 257 }
 258 
 259 void
 260 _krb5_plugin_free(struct krb5_plugin *list)
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 261 {
 262     struct krb5_plugin *next;
 263     while (list) {
 264         next = list->next;
 265         if (list->dsohandle)
 266             dlclose(list->dsohandle);
 267         free(list);
 268         list = next;
 269     }
 270 }

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