stdio.c revision 290544 
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. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: stable/10/lib/libc/stdio/stdio.c 290544 2015-11-08 13:37:16Z ache $");
38
39#include "namespace.h"
40#include <errno.h>
41#include <fcntl.h>
42#include <limits.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <unistd.h>
46#include "un-namespace.h"
47#include "local.h"
48
49/*
50 * Small standard I/O/seek/close functions.
51 */
52int
53__sread(void *cookie, char *buf, int n)
54{
55	FILE *fp = cookie;
56
57	return(_read(fp->_file, buf, (size_t)n));
58}
59
60int
61__swrite(void *cookie, char const *buf, int n)
62{
63	FILE *fp = cookie;
64
65	return (_write(fp->_file, buf, (size_t)n));
66}
67
68fpos_t
69__sseek(void *cookie, fpos_t offset, int whence)
70{
71	FILE *fp = cookie;
72
73	return (lseek(fp->_file, (off_t)offset, whence));
74}
75
76int
77__sclose(void *cookie)
78{
79
80	return (_close(((FILE *)cookie)->_file));
81}
82
83/*
84 * Higher level wrappers.
85 */
86int
87_sread(FILE *fp, char *buf, int n)
88{
89	int ret;
90
91	ret = (*fp->_read)(fp->_cookie, buf, n);
92	if (ret > 0) {
93		if (fp->_flags & __SOFF) {
94			if (fp->_offset <= OFF_MAX - ret)
95				fp->_offset += ret;
96			else
97				fp->_flags &= ~__SOFF;
98		}
99	} else if (ret < 0)
100		fp->_flags &= ~__SOFF;
101	return (ret);
102}
103
104int
105_swrite(FILE *fp, char const *buf, int n)
106{
107	int ret;
108	int serrno;
109
110	if (fp->_flags & __SAPP) {
111		serrno = errno;
112		if (_sseek(fp, (fpos_t)0, SEEK_END) == -1 &&
113		    (fp->_flags & __SOPT))
114			return (-1);
115		errno = serrno;
116	}
117	ret = (*fp->_write)(fp->_cookie, buf, n);
118	/* __SOFF removed even on success in case O_APPEND mode is set. */
119	if (ret >= 0) {
120		if ((fp->_flags & __SOFF) && !(fp->_flags2 & __S2OAP) &&
121		    fp->_offset <= OFF_MAX - ret)
122			fp->_offset += ret;
123		else
124			fp->_flags &= ~__SOFF;
125
126	} else if (ret < 0)
127		fp->_flags &= ~__SOFF;
128	return (ret);
129}
130
131fpos_t
132_sseek(FILE *fp, fpos_t offset, int whence)
133{
134	fpos_t ret;
135	int serrno, errret;
136
137	serrno = errno;
138	errno = 0;
139	ret = (*fp->_seek)(fp->_cookie, offset, whence);
140	errret = errno;
141	if (errno == 0)
142		errno = serrno;
143	/*
144	 * Disallow negative seeks per POSIX.
145	 * It is needed here to help upper level caller
146	 * in the cases it can't detect.
147	 */
148	if (ret < 0) {
149		if (errret == 0) {
150			if (offset != 0 || whence != SEEK_CUR) {
151				if (HASUB(fp))
152					FREEUB(fp);
153				fp->_p = fp->_bf._base;
154				fp->_r = 0;
155				fp->_flags &= ~__SEOF;
156			}
157			fp->_flags |= __SERR;
158			errno = EINVAL;
159		} else if (errret == ESPIPE)
160			fp->_flags &= ~__SAPP;
161		fp->_flags &= ~__SOFF;
162		ret = -1;
163	} else if (fp->_flags & __SOPT) {
164		fp->_flags |= __SOFF;
165		fp->_offset = ret;
166	}
167	return (ret);
168}
169