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 * Return file offset. 32 * Coordinates with buffering. 33 */ 34 #pragma weak _ftell = ftell 35 36 #include "lint.h" 37 #include "file64.h" 38 #include "mtlib.h" 39 #include <fcntl.h> 40 #include <stdio.h> 41 #include <thread.h> 42 #include <synch.h> 43 #include <errno.h> 44 #include <unistd.h> 45 #include <stddef.h> 46 #include <limits.h> 47 #include <sys/types.h> 48 #include "stdiom.h" 49 50 off64_t 51 ftell_common(FILE *iop) 52 { 53 ptrdiff_t adjust; 54 off64_t tres; 55 rmutex_t *lk; 56 57 FLOCKFILE(lk, iop); 58 59 /* 60 * If we're dealing with a memory stream, we need to flush the internal 61 * state before we try and determine the location. This is especially 62 * important for open_wmemstream() as it will have buffered bytes, but 63 * we need to convert that to wide characters before we proceed. If we 64 * have no file descriptor, then the units that the backing store are in 65 * can be arbitrary. 66 */ 67 if (_get_fd(iop) == -1) { 68 (void) _fflush_u(iop); 69 } 70 71 if (iop->_cnt < 0) 72 iop->_cnt = 0; 73 if (iop->_flag & _IOREAD) { 74 adjust = (ptrdiff_t)-iop->_cnt; 75 } else if (iop->_flag & (_IOWRT | _IORW)) { 76 adjust = 0; 77 if (((iop->_flag & (_IOWRT | _IONBF)) == _IOWRT) && 78 (iop->_base != 0)) { 79 adjust = iop->_ptr - iop->_base; 80 } else if ((iop->_flag & _IORW) && (iop->_base != 0)) { 81 adjust = (ptrdiff_t)-iop->_cnt; 82 } 83 } else { 84 errno = EBADF; /* file descriptor refers to no open file */ 85 FUNLOCKFILE(lk); 86 return (EOF); 87 } 88 89 tres = _xseek64(iop, 0, SEEK_CUR); 90 if (tres >= 0) 91 tres += adjust; 92 93 FUNLOCKFILE(lk); 94 return (tres); 95 } 96 97 long 98 ftell(FILE *iop) 99 { 100 off64_t tres; 101 102 tres = ftell_common(iop); 103 if (tres > LONG_MAX) { 104 errno = EOVERFLOW; 105 return (EOF); 106 } 107 108 return ((long)tres); 109 } 110