1 /* $NetBSD: refuse_log.c,v 1.2 2022/01/29 00:03:41 tnn Exp $ */ 2 3 /* 4 * Copyright (c) 2021 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote 16 * products derived from this software without specific prior written 17 * permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 20 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 25 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if !defined(lint) 34 __RCSID("$NetBSD: refuse_log.c,v 1.2 2022/01/29 00:03:41 tnn Exp $"); 35 #endif /* !lint */ 36 37 #include <assert.h> 38 #include <fuse_log.h> 39 #if defined(MULTITHREADED_REFUSE) 40 # include <pthread.h> 41 #endif 42 #include <stdio.h> 43 44 static void __printflike(2, 0) 45 default_log_func(enum fuse_log_level level __attribute__((__unused__)), 46 const char *fmt, va_list ap) { 47 /* This function needs to be thread-safe. Calling vfprintf(3) 48 * should be okay because POSIX mandates locking FILE* objects 49 * internally. */ 50 vfprintf(stderr, fmt, ap); 51 } 52 53 #if defined(MULTITHREADED_REFUSE) 54 static pthread_mutex_t log_func_mutex = PTHREAD_MUTEX_INITIALIZER; 55 #endif 56 static fuse_log_func_t log_func = default_log_func; 57 58 void 59 fuse_set_log_func(fuse_log_func_t func) { 60 #if defined(MULTITHREADED_REFUSE) 61 /* What we really need here is merely a memory barrier, but 62 * locking a mutex is the easiest way to achieve that. */ 63 int rv; 64 65 rv = pthread_mutex_lock(&log_func_mutex); 66 assert(rv == 0); 67 #endif 68 69 if (func) 70 log_func = func; 71 else 72 log_func = default_log_func; 73 74 #if defined(MULTITHREADED_REFUSE) 75 rv = pthread_mutex_unlock(&log_func_mutex); 76 assert(rv == 0); 77 #endif 78 } 79 80 void 81 fuse_log(enum fuse_log_level level, const char *fmt, ...) { 82 va_list ap; 83 #if defined(MULTITHREADED_REFUSE) 84 /* What we really need here is merely a memory barrier, but 85 * locking a mutex is the easiest way to achieve that. */ 86 int rv; 87 88 rv = pthread_mutex_lock(&log_func_mutex); 89 assert(rv == 0); 90 #endif 91 92 va_start(ap, fmt); 93 log_func(level, fmt, ap); 94 va_end(ap); 95 96 #if defined(MULTITHREADED_REFUSE) 97 rv = pthread_mutex_unlock(&log_func_mutex); 98 assert(rv == 0); 99 #endif 100 } 101