xref: /freebsd/lib/libc/stdio/stdio.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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 <errno.h>
37 #include <fcntl.h>
38 #include <limits.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <unistd.h>
42 #include "un-namespace.h"
43 #include "local.h"
44 
45 /*
46  * Small standard I/O/seek/close functions.
47  */
48 int
49 __sread(void *cookie, char *buf, int n)
50 {
51 	FILE *fp = cookie;
52 
53 	return(_read(fp->_file, buf, (size_t)n));
54 }
55 
56 int
57 __swrite(void *cookie, char const *buf, int n)
58 {
59 	FILE *fp = cookie;
60 
61 	return (_write(fp->_file, buf, (size_t)n));
62 }
63 
64 fpos_t
65 __sseek(void *cookie, fpos_t offset, int whence)
66 {
67 	FILE *fp = cookie;
68 
69 	return (lseek(fp->_file, (off_t)offset, whence));
70 }
71 
72 int
73 __sclose(void *cookie)
74 {
75 
76 	return (_close(((FILE *)cookie)->_file));
77 }
78 
79 /*
80  * Higher level wrappers.
81  */
82 int
83 _sread(FILE *fp, char *buf, int n)
84 {
85 	int ret;
86 
87 	ret = (*fp->_read)(fp->_cookie, buf, n);
88 	if (ret > 0) {
89 		if (fp->_flags & __SOFF) {
90 			if (fp->_offset <= OFF_MAX - ret)
91 				fp->_offset += ret;
92 			else
93 				fp->_flags &= ~__SOFF;
94 		}
95 	} else if (ret < 0)
96 		fp->_flags &= ~__SOFF;
97 	return (ret);
98 }
99 
100 int
101 _swrite(FILE *fp, char const *buf, int n)
102 {
103 	int ret;
104 	int serrno;
105 
106 	if (fp->_flags & __SAPP) {
107 		serrno = errno;
108 		if (_sseek(fp, (fpos_t)0, SEEK_END) == -1 &&
109 		    (fp->_flags & __SOPT))
110 			return (-1);
111 		errno = serrno;
112 	}
113 	ret = (*fp->_write)(fp->_cookie, buf, n);
114 	/* __SOFF removed even on success in case O_APPEND mode is set. */
115 	if (ret >= 0) {
116 		if ((fp->_flags & __SOFF) && !(fp->_flags2 & __S2OAP) &&
117 		    fp->_offset <= OFF_MAX - ret)
118 			fp->_offset += ret;
119 		else
120 			fp->_flags &= ~__SOFF;
121 
122 	} else if (ret < 0)
123 		fp->_flags &= ~__SOFF;
124 	return (ret);
125 }
126 
127 fpos_t
128 _sseek(FILE *fp, fpos_t offset, int whence)
129 {
130 	fpos_t ret;
131 	int serrno, errret;
132 
133 	serrno = errno;
134 	errno = 0;
135 	ret = (*fp->_seek)(fp->_cookie, offset, whence);
136 	errret = errno;
137 	if (errno == 0)
138 		errno = serrno;
139 	/*
140 	 * Disallow negative seeks per POSIX.
141 	 * It is needed here to help upper level caller
142 	 * in the cases it can't detect.
143 	 */
144 	if (ret < 0) {
145 		if (errret == 0) {
146 			if (offset != 0 || whence != SEEK_CUR) {
147 				if (HASUB(fp))
148 					FREEUB(fp);
149 				fp->_p = fp->_bf._base;
150 				fp->_r = 0;
151 				fp->_flags &= ~__SEOF;
152 			}
153 			fp->_flags |= __SERR;
154 			errno = EINVAL;
155 		} else if (errret == ESPIPE)
156 			fp->_flags &= ~__SAPP;
157 		fp->_flags &= ~__SOFF;
158 		ret = -1;
159 	} else if (fp->_flags & __SOPT) {
160 		fp->_flags |= __SOFF;
161 		fp->_offset = ret;
162 	}
163 	return (ret);
164 }
165 
166 void
167 __stdio_cancel_cleanup(void * arg)
168 {
169 
170 	if (arg != NULL)
171 		_funlockfile((FILE *)arg);
172 }
173