Add first version of the plugin interface.

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@18997 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/plugin.c

@@ -0,0 +1,230 @@
+/*
+ * Copyright (c) 2006 Kungliga Tekniska H<>gskolan
+ * (Royal Institute of Technology, Stockholm, Sweden). 
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ *
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ */
+
+#include "krb5_locl.h"
+RCSID("$Id$");
+#ifdef HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+#include <dirent.h>
+
+struct krb5_plugin {
+    void *symbol;
+    void *dsohandle;
+    struct krb5_plugin *next;
+};
+
+struct plugin {
+    enum plugin_type type;
+    void *name;
+    void *symbol;
+    struct plugin *next;
+};
+
+static HEIMDAL_MUTEX plugin_mutex = HEIMDAL_MUTEX_INITIALIZER;
+struct plugin *registered = NULL;
+
+/*
+ *
+ */
+
+void *
+_krb5_plugin_get_symbol(struct krb5_plugin *p)
+{
+    return p->symbol;
+}
+
+struct krb5_plugin *
+_krb5_plugin_get_next(struct krb5_plugin *p)
+{
+    return p->next;
+}
+
+/*
+ *
+ */
+
+static krb5_error_code
+loadlib(krb5_context context,
+	enum plugin_type type,
+	const char *name,
+	const char *lib,
+	struct krb5_plugin **e)
+{
+    *e = calloc(1, sizeof(**e));
+    if (*e == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+
+    (*e)->dsohandle = dlopen(lib, 0);
+    if ((*e)->dsohandle == NULL) {
+	free(*e);
+	krb5_set_error_string(context, "Failed to load %s: %s", 
+			      lib, dlerror());
+	return ENOMEM;
+    }
+
+    /* dlsym doesn't care about the type */
+    (*e)->symbol = dlsym((*e)->dsohandle, name);
+    if ((*e)->symbol == NULL) {
+	dlclose((*e)->dsohandle);
+	free(*e);
+	krb5_clear_error_string(context);
+	return ENOMEM;
+    }
+
+    return 0;
+}
+
+krb5_error_code
+_krb5_plugin_register(krb5_context context,
+		      enum plugin_type type,
+		      const char *name, 
+		      void *symbol)
+{
+    struct plugin *e;
+
+    e = calloc(1, sizeof(*e));
+    if (e == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    e->type = type;
+    e->name = strdup(name);
+    if (e->name == NULL) {
+	free(e);
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    e->symbol = symbol;
+
+    HEIMDAL_MUTEX_lock(&plugin_mutex);
+    e->next = registered;
+    registered = e;
+    HEIMDAL_MUTEX_unlock(&plugin_mutex);
+
+    return 0;
+}
+
+krb5_error_code
+_krb5_plugin_find(krb5_context context,
+		  enum plugin_type type,
+		  const char *name, 
+		  struct krb5_plugin **list)
+{
+    struct krb5_plugin *e;
+    struct plugin *p;
+    krb5_error_code ret;
+    const char *dir;
+    struct dirent *entry;
+    char *path;
+    DIR *d = NULL;
+
+    *list = NULL;
+
+    HEIMDAL_MUTEX_lock(&plugin_mutex);
+
+    for (p = registered; p != NULL; p = p->next) {
+	if (p->type != type || strcmp(p->name, name) != 0)
+	    continue;
+
+	e = calloc(1, sizeof(*e));
+	if (e == NULL) {
+	    HEIMDAL_MUTEX_unlock(&plugin_mutex);
+	    krb5_set_error_string(context, "out of memory");
+	    ret = ENOMEM;
+	    goto out;
+	}
+	e->symbol = p->symbol;
+	e->dsohandle = NULL;
+	e->next = *list;
+	*list = e;
+    }
+    HEIMDAL_MUTEX_unlock(&plugin_mutex);
+
+    dir = "/usr/heimdal/lib/krb5/plugins";
+
+    /* XXX allow more directories */
+
+    d = opendir(dir);
+    if (d == NULL) {
+	if (*list == NULL) {
+	    ret = errno;
+	    krb5_set_error_string(context, "failed to open directory %s", dir);
+	    return ret;
+	}
+	return 0;
+    }
+
+    while ((entry = readdir(d)) != NULL) {
+	asprintf(&path, "%s/%s", dir, entry->d_name);
+	if (path == NULL) {
+	    krb5_set_error_string(context, "out of memory");
+	    ret = ENOMEM;
+	    goto out;
+	}
+	ret = loadlib(context, type, name, path, &e);
+	free(path);
+	if (ret)
+	    continue;
+
+	e->next = *list;
+	*list = e;
+    }
+    closedir(d);
+
+    return 0;
+
+out:
+    if (d)
+	closedir(d);
+    _krb5_plugin_free(*list);
+    *list = NULL;
+
+    return ret;
+}
+
+void
+_krb5_plugin_free(struct krb5_plugin *list)
+{
+    struct krb5_plugin *next;
+    while (list) {
+	next = list->next;
+	if (list->dsohandle)
+	    dlclose(list->dsohandle);
+	free(list);
+	list = next;
+    }
+}
+