1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/* $NetBSD: makebuf.c,v 1.18 2015/07/15 19:08:43 christos Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)makebuf.c 8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: makebuf.c,v 1.18 2015/07/15 19:08:43 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include <ctype.h>
#include "reentrant.h"
#include "local.h"
/*
* Override the file buffering based on the environment setting STDBUF%d
* (for the specific file descriptor) and STDBUF (for all descriptors).
* the setting is ULB<num> standing for "Unbuffered", "Linebuffered",
* and Fullybuffered", and <num> is a value from 0 to 1M.
*/
static int
__senvbuf(FILE *fp, size_t *size, int *couldbetty)
{
char evb[64], *evp;
int flags, e;
intmax_t s;
flags = 0;
if (snprintf(evb, sizeof(evb), "STDBUF%d", fp->_file) < 0)
return flags;
if ((evp = getenv(evb)) == NULL && (evp = getenv("STDBUF")) == NULL)
return flags;
switch (*evp) {
case 'u':
case 'U':
evp++;
flags |= __SNBF;
break;
case 'l':
case 'L':
evp++;
flags |= __SLBF;
break;
case 'f':
case 'F':
evp++;
*couldbetty = 0;
break;
}
if (!isdigit((unsigned char)*evp))
return flags;
s = strtoi(evp, NULL, 0, 0, 1024 * 1024, &e);
if (e != 0)
return flags;
*size = (size_t)s;
if (*size == 0)
return __SNBF;
return flags;
}
/*
* Allocate a file buffer, or switch to unbuffered I/O.
* Per the ANSI C standard, ALL tty devices default to line buffered.
*
* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
* optimisation) right after the fstat() that finds the buffer size.
*/
void
__smakebuf(FILE *fp)
{
void *p;
int flags;
size_t size;
int couldbetty;
_DIAGASSERT(fp != NULL);
if (fp->_flags & __SNBF)
goto unbuf;
flags = __swhatbuf(fp, &size, &couldbetty);
if ((fp->_flags & (__SLBF|__SNBF|__SMBF)) == 0
&& fp->_cookie == fp && fp->_file >= 0) {
flags |= __senvbuf(fp, &size, &couldbetty);
if (flags & __SNBF)
goto unbuf;
}
if ((p = malloc(size)) == NULL)
goto unbuf;
__cleanup = _cleanup;
flags |= __SMBF;
fp->_bf._base = fp->_p = p;
_DIAGASSERT(__type_fit(int, size));
fp->_bf._size = (int)size;
if (couldbetty && isatty(__sfileno(fp)))
flags |= __SLBF;
fp->_flags |= flags;
return;
unbuf:
fp->_flags |= __SNBF;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
}
/*
* Internal routine to determine `proper' buffering for a file.
*/
int
__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
{
struct stat st;
_DIAGASSERT(fp != NULL);
_DIAGASSERT(bufsize != NULL);
_DIAGASSERT(couldbetty != NULL);
if (__sfileno(fp) == -1 || fstat(__sfileno(fp), &st) < 0) {
*couldbetty = 0;
*bufsize = BUFSIZ;
return __SNPT;
}
/* could be a tty iff it is a character device */
*couldbetty = S_ISCHR(st.st_mode);
if (st.st_blksize == 0) {
*bufsize = BUFSIZ;
return __SNPT;
}
/*
* Optimise fseek() only if it is a regular file. (The test for
* __sseek is mainly paranoia.) It is safe to set _blksize
* unconditionally; it will only be used if __SOPT is also set.
*/
*bufsize = st.st_blksize;
fp->_blksize = st.st_blksize;
return (st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
__SOPT : __SNPT;
}
|
