1 files changed, 417 insertions, 0 deletions
diff --git a/agents/virt/server/plugin.c b/agents/virt/server/plugin.c
new file mode 100644
index 0000000..d9a69fb
--- /dev/null
+++ b/agents/virt/server/plugin.c
@@ -0,0 +1,417 @@
+/*
+  Copyright Red Hat, Inc. 2002-2004, 2009
+
+  The Magma Cluster API Library is free software; you can redistribute
+  it and/or modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either version
+  2.1 of the License, or (at your option) any later version.
+
+  The Magma Cluster API Library is distributed in the hope that it will
+  be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+ */
+/** @file
+ * Plugin loading routines
+ */
+
+#include "config.h"
+
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <malloc.h>
+#include <string.h>
+#include <dirent.h>
+
+#include "list.h"
+#include "simpleconfig.h"
+#include "static_map.h"
+#include "server_plugin.h"
+#include "debug.h"
+
+typedef struct _plugin_list {
+	list_head();
+	const listener_plugin_t *listener;
+	const backend_plugin_t *backend;
+	void *handle;
+	plugin_type_t type;
+} plugin_list_t;
+
+static plugin_list_t *server_plugins = NULL;
+
+
+static int
+plugin_reg_backend(void *handle, const backend_plugin_t *plugin)
+{
+	plugin_list_t *newplug;
+
+	if (plugin_find_backend(plugin->name)) {
+		errno = EEXIST;
+		return -1;
+	}
+
+	newplug = malloc(sizeof(*newplug));
+	if (!newplug) 
+		return -1;
+	memset(newplug, 0, sizeof(*newplug));
+	newplug->backend = plugin;
+	newplug->type = PLUGIN_BACKEND;
+	newplug->handle = handle;
+
+	list_insert(&server_plugins, newplug);
+	return 0;
+}
+
+
+static int
+plugin_reg_listener(void *handle, const listener_plugin_t *plugin)
+{
+	plugin_list_t *newplug;
+
+	if (plugin_find_listener(plugin->name)) {
+		errno = EEXIST;
+		return -1;
+	}
+
+	newplug = malloc(sizeof(*newplug));
+	if (!newplug) 
+		return -1;
+	memset(newplug, 0, sizeof(*newplug));
+	newplug->listener = plugin;
+	newplug->type = PLUGIN_LISTENER;
+	newplug->handle = handle;
+
+	list_insert(&server_plugins, newplug);
+	return 0;
+}
+
+
+void
+plugin_dump(void)
+{
+	plugin_list_t *p;
+	int x, y;
+
+	y = 0;
+	list_for(&server_plugins, p, x) {
+		if (p->type == PLUGIN_BACKEND) {
+			if (!y) {
+				y = 1;
+				printf("Available backends:\n");
+			}
+			printf("    %s %s\n",
+			       p->backend->name, p->backend->version);
+		}
+	}
+
+	y = 0;
+	list_for(&server_plugins, p, x) {
+		if (p->type == PLUGIN_LISTENER) {
+			if (!y) {
+				y = 1;
+				printf("Available listeners:\n");
+			}
+			printf("    %s %s\n",
+			       p->listener->name, p->listener->version);
+		}
+	}
+}
+
+
+const backend_plugin_t *
+plugin_find_backend(const char *name)
+{
+	plugin_list_t *p;
+	int x;
+
+	list_for(&server_plugins, p, x) {
+		if (p->type != PLUGIN_BACKEND)
+			continue;
+		if (!strcasecmp(name, p->backend->name))
+			return p->backend;
+	}
+
+	return NULL;
+}
+
+
+const listener_plugin_t *
+plugin_find_listener(const char *name)
+{
+	plugin_list_t *p;
+	int x;
+
+	list_for(&server_plugins, p, x) {
+		if (p->type != PLUGIN_LISTENER)
+			continue;
+		if (!strcasecmp(name, p->listener->name))
+			return p->listener;
+	}
+
+	return NULL;
+}
+
+
+static int
+backend_plugin_load(void *handle, const char *libpath)
+{
+	const backend_plugin_t *plug = NULL;
+	double (*modversion)(void);
+	backend_plugin_t *(*modinfo)(void);
+
+	modversion = dlsym(handle, BACKEND_VER_STR);
+	if (!modversion) {
+		dbg_printf(1, "Failed to map %s\n", BACKEND_VER_STR);
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (modversion() != PLUGIN_VERSION_BACKEND) {
+		dbg_printf(1, "API version mismatch in %s: \n"
+			   "       %f expected; %f received.\n", libpath,
+			   PLUGIN_VERSION_BACKEND, modversion());
+		errno = EINVAL;
+		return -1;
+	}
+
+	modinfo = dlsym(handle, BACKEND_INFO_STR);
+	if (!modinfo) {
+		dbg_printf(1, "Failed to map %s\n", BACKEND_INFO_STR);
+		errno = EINVAL;
+		return -1;
+	}
+
+	plug = modinfo();
+	if (plugin_reg_backend(handle, plug) < 0) {
+		dbg_printf(1, "Failed to register %s %s\n", plug->name,
+			   plug->version);
+		errno = EINVAL;
+		return -1;
+	} else {
+		dbg_printf(1, "Registered backend plugin %s %s\n",
+			   plug->name, plug->version);
+	}
+
+	return 0;
+}
+
+
+static int
+listener_plugin_load(void *handle, const char *libpath)
+{
+	const listener_plugin_t *plug = NULL;
+	double (*modversion)(void);
+	listener_plugin_t *(*modinfo)(void);
+
+	modversion = dlsym(handle, LISTENER_VER_STR);
+	if (!modversion) {
+		dbg_printf(1, "Failed to map %s\n", LISTENER_VER_STR);
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (modversion() != PLUGIN_VERSION_LISTENER) {
+		dbg_printf(1, "API version mismatch in %s: \n"
+		       	   "       %f expected; %f received.\n", libpath,
+			   PLUGIN_VERSION_LISTENER, modversion());
+		dlclose(handle);
+		errno = EINVAL;
+		return -1;
+	}
+
+	modinfo = dlsym(handle, LISTENER_INFO_STR);
+	if (!modinfo) {
+		dbg_printf(1, "Failed to map %s\n", LISTENER_INFO_STR);
+		errno = EINVAL;
+		return -1;
+	}
+
+	plug = modinfo();
+	if (plugin_reg_listener(handle, plug) < 0) {
+		dbg_printf(1, "Failed to register %s %s\n", plug->name,
+			   plug->version);
+		errno = EINVAL;
+		return -1;
+	} else {
+		dbg_printf(1, "Registered listener plugin %s %s\n",
+			   plug->name, plug->version);
+	}
+
+	return 0;
+}
+
+
+/**
+ * Load a cluster plugin .so file and map all the functions
+ * provided to entries in a backend_plugin_t structure.
+ *
+ * @param libpath	Path to file.
+ * @return		NULL on failure, or plugin-specific
+ * 			(const) backend_plugin_t * structure on
+ * 			success.
+ */
+int
+plugin_load(const char *libpath)
+{
+	void *handle = NULL;
+
+	errno = 0;
+
+	if (!libpath) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	dbg_printf(3, "Loading plugin from %s\n", libpath);
+	handle = dlopen(libpath, RTLD_NOW);
+	if (!handle) {
+		dbg_printf(3, "Could not dlopen %s: %s\n", libpath, dlerror());
+		errno = ELIBACC;
+		return -1;
+	}
+
+	if (!backend_plugin_load(handle, libpath) ||
+	    !listener_plugin_load(handle, libpath))
+		return 0;
+
+	dbg_printf(3, "%s is not a valid plugin\n", libpath);
+	dlclose(handle);
+	errno = EINVAL;
+	return -1;
+}
+
+void
+plugin_unload(void)
+{
+	plugin_list_t *p;
+	int x;
+
+	list_for(&server_plugins, p, x) {
+		dlclose(p->handle);
+	}
+}
+
+/**
+  Free up a null-terminated array of strings
+ */
+static void
+free_dirnames(char **dirnames)
+{
+	int x = 0;
+
+	for (; dirnames[x]; x++)
+		free(dirnames[x]);
+
+	free(dirnames);
+}
+
+
+static int
+_compare(const void *a, const void *b)
+{
+	return strcmp((const char *)a, (const char *)b);
+}
+
+
+/**
+  Read all entries in a directory and return them in a NULL-terminated,
+  sorted array.
+ */
+static int
+read_dirnames_sorted(const char *directory, char ***dirnames)
+{
+	DIR *dir;
+	struct dirent *entry;
+	char filename[1024];
+	int count = 0, x = 0;
+
+	dir = opendir(directory);
+	if (!dir)
+		return -1;
+
+	/* Count the number of plugins */
+	while ((entry = readdir(dir)) != NULL)
+		++count;
+
+	/* Malloc the entries */
+	*dirnames = malloc(sizeof(char *) * (count+1));
+	if (!*dirnames) {
+#ifdef DEBUG
+		printf("%s: Failed to malloc %d bytes",
+		       __FUNCTION__, (int)(sizeof(char *) * (count+1)));
+#endif
+		closedir(dir);
+		errno = ENOMEM;
+		return -1;
+	}
+	memset(*dirnames, 0, sizeof(char *) * (count + 1));
+	rewinddir(dir);
+
+	/* Store the directory names. */
+	while ((entry = readdir(dir)) != NULL) {
+		snprintf(filename, sizeof(filename), "%s/%s", directory,
+			 entry->d_name);
+
+		(*dirnames)[x] = strdup(filename);
+		if (!(*dirnames)[x]) {
+#ifdef DEBUG
+			printf("Failed to duplicate %s\n",
+			       filename);
+#endif
+			free_dirnames(*dirnames);
+			closedir(dir);
+			errno = ENOMEM;
+			return -1;
+		}
+		++x;
+	}
+
+	closedir(dir);
+
+	/* Sort the directory names. */
+	qsort((*dirnames), count, sizeof(char *), _compare);
+
+	return 0;
+}
+
+
+/**
+ */
+int
+plugin_search(const char *pathname)
+{
+	int found = 0;
+	int fcount = 0;
+	char **filenames;
+
+	dbg_printf(1, "Searching for plugins in %s\n", pathname);
+	if (read_dirnames_sorted(pathname, &filenames) != 0) {
+		return -1;
+	}
+
+	for (fcount = 0; filenames[fcount]; fcount++) {
+
+		if (plugin_load(filenames[fcount]) == 0)
+			++found;
+	}
+
+	free_dirnames(filenames);
+	if (!found) {
+		dbg_printf(1, "No usable plugins found.\n");
+		errno = ELIBACC;
+		return -1;
+	}
+
+	return found;
+}