1 /* $NetBSD: external_locking.c,v 1.1.1.1 2008/12/22 00:18:04 haad Exp $ */ 2 3 /* 4 * Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved. 5 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. 6 * 7 * This file is part of LVM2. 8 * 9 * This copyrighted material is made available to anyone wishing to use, 10 * modify, copy, or redistribute it subject to the terms and conditions 11 * of the GNU Lesser General Public License v.2.1. 12 * 13 * You should have received a copy of the GNU Lesser General Public License 14 * along with this program; if not, write to the Free Software Foundation, 15 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 16 */ 17 18 #include "lib.h" 19 #include "locking_types.h" 20 #include "defaults.h" 21 #include "sharedlib.h" 22 #include "toolcontext.h" 23 24 static void *_locking_lib = NULL; 25 static void (*_reset_fn) (void) = NULL; 26 static void (*_end_fn) (void) = NULL; 27 static int (*_lock_fn) (struct cmd_context * cmd, const char *resource, 28 uint32_t flags) = NULL; 29 static int (*_init_fn) (int type, struct config_tree * cft, 30 uint32_t *flags) = NULL; 31 32 static int _lock_resource(struct cmd_context *cmd, const char *resource, 33 uint32_t flags) 34 { 35 if (_lock_fn) 36 return _lock_fn(cmd, resource, flags); 37 else 38 return 0; 39 } 40 41 static void _fin_external_locking(void) 42 { 43 if (_end_fn) 44 _end_fn(); 45 46 dlclose(_locking_lib); 47 48 _locking_lib = NULL; 49 _init_fn = NULL; 50 _end_fn = NULL; 51 _lock_fn = NULL; 52 _reset_fn = NULL; 53 } 54 55 static void _reset_external_locking(void) 56 { 57 if (_reset_fn) 58 _reset_fn(); 59 } 60 61 int init_external_locking(struct locking_type *locking, struct cmd_context *cmd) 62 { 63 const char *libname; 64 65 if (_locking_lib) { 66 log_error("External locking already initialised"); 67 return 1; 68 } 69 70 locking->lock_resource = _lock_resource; 71 locking->fin_locking = _fin_external_locking; 72 locking->reset_locking = _reset_external_locking; 73 locking->flags = 0; 74 75 libname = find_config_tree_str(cmd, "global/locking_library", 76 DEFAULT_LOCKING_LIB); 77 78 if (!(_locking_lib = load_shared_library(cmd, libname, "locking", 1))) 79 return_0; 80 81 /* Get the functions we need */ 82 if (!(_init_fn = dlsym(_locking_lib, "locking_init")) || 83 !(_lock_fn = dlsym(_locking_lib, "lock_resource")) || 84 !(_reset_fn = dlsym(_locking_lib, "reset_locking")) || 85 !(_end_fn = dlsym(_locking_lib, "locking_end"))) { 86 log_error("Shared library %s does not contain locking " 87 "functions", libname); 88 dlclose(_locking_lib); 89 _locking_lib = NULL; 90 return 0; 91 } 92 93 log_verbose("Loaded external locking library %s", libname); 94 return _init_fn(2, cmd->cft, &locking->flags); 95 } 96