1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "namespace.h" 36 #include <sys/types.h> 37 #include <errno.h> 38 #include <limits.h> 39 #include <stdio.h> 40 #include "un-namespace.h" 41 #include "local.h" 42 #include "libc_private.h" 43 44 /* 45 * standard ftell function. 46 */ 47 long 48 ftell(FILE *fp) 49 { 50 off_t rv; 51 52 rv = ftello(fp); 53 if (rv > LONG_MAX) { 54 errno = EOVERFLOW; 55 return (-1); 56 } 57 return (rv); 58 } 59 60 /* 61 * ftello: return current offset. 62 */ 63 off_t 64 ftello(FILE *fp) 65 { 66 fpos_t rv; 67 int ret; 68 69 FLOCKFILE(fp); 70 ret = _ftello(fp, &rv); 71 FUNLOCKFILE(fp); 72 if (ret) 73 return (-1); 74 if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ 75 errno = ESPIPE; 76 return (-1); 77 } 78 return (rv); 79 } 80 81 int 82 _ftello(FILE *fp, fpos_t *offset) 83 { 84 fpos_t pos; 85 size_t n; 86 87 if (fp->_seek == NULL) { 88 errno = ESPIPE; /* historic practice */ 89 return (1); 90 } 91 92 /* 93 * Find offset of underlying I/O object, then 94 * adjust for buffered bytes. 95 */ 96 if (!(fp->_flags & __SRD) && (fp->_flags & __SWR) && 97 fp->_p != NULL && fp->_p - fp->_bf._base > 0 && 98 ((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP))) { 99 pos = _sseek(fp, (fpos_t)0, SEEK_END); 100 if (pos == -1) 101 return (1); 102 } else if (fp->_flags & __SOFF) 103 pos = fp->_offset; 104 else { 105 pos = _sseek(fp, (fpos_t)0, SEEK_CUR); 106 if (pos == -1) 107 return (1); 108 } 109 if (fp->_flags & __SRD) { 110 /* 111 * Reading. Any unread characters (including 112 * those from ungetc) cause the position to be 113 * smaller than that in the underlying object. 114 */ 115 if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { 116 fp->_flags |= __SERR; 117 errno = EIO; 118 return (1); 119 } 120 if (HASUB(fp)) 121 pos -= fp->_r; /* Can be negative at this point. */ 122 } else if ((fp->_flags & __SWR) && fp->_p != NULL && 123 (n = fp->_p - fp->_bf._base) > 0) { 124 /* 125 * Writing. Any buffered characters cause the 126 * position to be greater than that in the 127 * underlying object. 128 */ 129 if (pos > OFF_MAX - n) { 130 errno = EOVERFLOW; 131 return (1); 132 } 133 pos += n; 134 } 135 *offset = pos; 136 return (0); 137 } 138