xref: /freebsd/lib/libc/stdio/stdio.c (revision 2b15cb3d0922bd70ea592f0da9b4a5b167f4d53f)
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)
34 static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
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  */
52 int
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 
60 int
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 
68 fpos_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 
76 int
77 __sclose(void *cookie)
78 {
79 
80 	return (_close(((FILE *)cookie)->_file));
81 }
82 
83 /*
84  * Higher level wrappers.
85  */
86 int
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 
104 int
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 & (__SAPP|__SOFF)) == (__SAPP|__SOFF) &&
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 
131 fpos_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