1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * ftruncate() and truncate() set a file to a specified 32 * length using fcntl(F_FREESP) system call. If the file 33 * was previously longer than length, the bytes past the 34 * length will no longer be accessible. If it was shorter, 35 * bytes not written will be zero filled. 36 */ 37 38 #include <sys/feature_tests.h> 39 40 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64 41 #pragma weak _ftruncate64 = ftruncate64 42 #pragma weak _truncate64 = truncate64 43 #define ftruncate ftruncate64 44 #define truncate truncate64 45 #endif /* !_LP64 && _FILE_OFFSET_BITS == 64 */ 46 47 #include "lint.h" 48 #include <unistd.h> 49 #include <stdio.h> 50 #include <fcntl.h> 51 #include <pthread.h> 52 #include <sys/types.h> 53 54 int 55 ftruncate(int fildes, off_t len) 56 { 57 struct flock lck; 58 59 lck.l_whence = 0; /* offset l_start from beginning of file */ 60 lck.l_start = len; 61 lck.l_type = F_WRLCK; /* setting a write lock */ 62 lck.l_len = (off_t)0; /* until the end of the file address space */ 63 64 if (fcntl(fildes, F_FREESP, &lck) == -1) { 65 return (-1); 66 } 67 return (0); 68 } 69 70 int 71 truncate(const char *path, off_t len) 72 { 73 74 int rval = 0; 75 int cancel_state; 76 int fd; 77 78 /* 79 * truncate() is not a cancellation point, 80 * even though it calls open() and close(). 81 */ 82 (void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state); 83 if ((fd = open(path, O_WRONLY)) == -1 || ftruncate(fd, len) == -1) 84 rval = -1; 85 if (fd >= 0) 86 (void) close(fd); 87 (void) pthread_setcancelstate(cancel_state, NULL); 88 return (rval); 89 } 90