1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <sys/types.h> 45 #include <errno.h> 46 #include <limits.h> 47 #include <stdio.h> 48 #include "un-namespace.h" 49 #include "local.h" 50 #include "libc_private.h" 51 52 /* 53 * standard ftell function. 54 */ 55 long 56 ftell(fp) 57 FILE *fp; 58 { 59 off_t rv; 60 61 rv = ftello(fp); 62 if (rv > LONG_MAX) { 63 errno = EOVERFLOW; 64 return (-1); 65 } 66 return (rv); 67 } 68 69 /* 70 * ftello: return current offset. 71 */ 72 off_t 73 ftello(fp) 74 FILE *fp; 75 { 76 fpos_t rv; 77 int ret; 78 79 FLOCKFILE(fp); 80 ret = _ftello(fp, &rv); 81 FUNLOCKFILE(fp); 82 if (ret) 83 return (-1); 84 if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ 85 errno = ESPIPE; 86 return (-1); 87 } 88 return (rv); 89 } 90 91 int 92 _ftello(fp, offset) 93 FILE *fp; 94 fpos_t *offset; 95 { 96 fpos_t pos; 97 size_t n; 98 99 if (fp->_seek == NULL) { 100 errno = ESPIPE; /* historic practice */ 101 return (1); 102 } 103 104 /* 105 * Find offset of underlying I/O object, then 106 * adjust for buffered bytes. 107 */ 108 if (fp->_flags & __SOFF) 109 pos = fp->_offset; 110 else { 111 pos = _sseek(fp, (fpos_t)0, SEEK_CUR); 112 if (pos == -1) 113 return (1); 114 } 115 if (fp->_flags & __SRD) { 116 /* 117 * Reading. Any unread characters (including 118 * those from ungetc) cause the position to be 119 * smaller than that in the underlying object. 120 */ 121 if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { 122 fp->_flags |= __SERR; 123 errno = EIO; 124 return (1); 125 } 126 if (HASUB(fp)) 127 pos -= fp->_r; /* Can be negative at this point. */ 128 } else if ((fp->_flags & __SWR) && fp->_p != NULL) { 129 /* 130 * Writing. Any buffered characters cause the 131 * position to be greater than that in the 132 * underlying object. 133 */ 134 n = fp->_p - fp->_bf._base; 135 if (pos > OFF_MAX - n) { 136 errno = EOVERFLOW; 137 return (1); 138 } 139 pos += n; 140 } 141 *offset = pos; 142 return (0); 143 } 144