lib/misc/sharedlib.c

/*
 * Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
 *
 * This file is part of LVM2.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "lib.h"
#include "config.h"
#include "sharedlib.h"
#include "toolcontext.h"

#include <limits.h>
#include <sys/stat.h>
#include <dlfcn.h>

void get_shared_library_path(struct cmd_context *cmd, const char *libname,
			     char *path, size_t path_len)
{
	struct stat info;

	if (!path_len)
		return;

	/* If libname doesn't begin with '/' then use lib_dir/libname,
	 * if present */
	if (libname[0] == '/' ||
	    (!cmd->lib_dir &&
	     !(cmd->lib_dir = find_config_tree_str(cmd, global_library_dir_CFG, NULL))) ||
	    (dm_snprintf(path, path_len, "%s/%s", cmd->lib_dir,
			 libname) == -1) || stat(path, &info) == -1) {
		strncpy(path, libname, path_len - 1);
		path[path_len - 1] = '\0';
	}
}

void *load_shared_library(struct cmd_context *cmd, const char *libname,
			  const char *desc, int silent)
{
	char path[PATH_MAX];
	void *library;

	if (is_static()) {
		log_error("Not loading shared %s library %s in static mode.",
			  desc, libname);
		return NULL;
	}

	get_shared_library_path(cmd, libname, path, sizeof(path));

	log_very_verbose("Opening shared %s library %s", desc, path);

	if (!(library = dlopen(path, RTLD_LAZY | RTLD_GLOBAL))) {
		if (silent && ignorelockingfailure())
			log_verbose("Unable to open external %s library %s: %s",
				    desc, path, dlerror());
		else
			log_error("Unable to open external %s library %s: %s",
				  desc, path, dlerror());
	}

	return library;
}