1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <errno.h> 30 #include <stdio.h> 31 32 #include "local.h" 33 34 // We can't use the OpenBSD implementation which uses kernel-specific 35 // APIs not available on Linux. Instead we use a pthread_mutex_t within 36 // struct __sfileext (see fileext.h). 37 38 void flockfile(FILE* fp) { 39 if (fp != nullptr) { 40 pthread_mutex_lock(&_FLOCK(fp)); 41 } 42 } 43 44 int ftrylockfile(FILE* fp) { 45 // The specification for ftrylockfile() says it returns 0 on success, 46 // or non-zero on error. So return an errno code directly on error. 47 if (fp == nullptr) { 48 return EINVAL; 49 } 50 51 return pthread_mutex_trylock(&_FLOCK(fp)); 52 } 53 54 void funlockfile(FILE* fp) { 55 if (fp != nullptr) { 56 pthread_mutex_unlock(&_FLOCK(fp)); 57 } 58 } 59
