1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31 #include <err.h>
32 #include <errno.h>
33 #include <limits.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37
38 static const char *
stream_name(FILE * s)39 stream_name(FILE *s)
40 {
41
42 if (s == stdin)
43 return "stdin";
44 if (s == stdout)
45 return "stdout";
46 if (s == stderr)
47 return "stderr";
48 /* This should not happen. */
49 abort();
50 }
51
52 static void
change_buf(FILE * s,const char * bufmode)53 change_buf(FILE *s, const char *bufmode)
54 {
55 char *unit;
56 size_t bufsize;
57 int mode;
58
59 bufsize = 0;
60 if (bufmode[0] == '0' && bufmode[1] == '\0')
61 mode = _IONBF;
62 else if (bufmode[0] == 'L' && bufmode[1] == '\0')
63 mode = _IOLBF;
64 else if (bufmode[0] == 'B' && bufmode[1] == '\0') {
65 mode = _IOFBF;
66 bufsize = 0;
67 } else {
68 /*
69 * This library being preloaded, depending on libutil
70 * would lead to excessive namespace pollution.
71 * Thus we do not use expand_number().
72 */
73 errno = 0;
74 bufsize = strtol(bufmode, &unit, 0);
75 if (errno == EINVAL || errno == ERANGE || unit == bufmode)
76 warn("Wrong buffer mode '%s' for %s", bufmode,
77 stream_name(s));
78 switch (*unit) {
79 case 'G':
80 bufsize *= 1024 * 1024 * 1024;
81 break;
82 case 'M':
83 bufsize *= 1024 * 1024;
84 break;
85 case 'k':
86 bufsize *= 1024;
87 break;
88 case '\0':
89 break;
90 default:
91 warnx("Unknown suffix '%c' for %s", *unit,
92 stream_name(s));
93 return;
94 }
95 mode = _IOFBF;
96 }
97 if (setvbuf(s, NULL, mode, bufsize) != 0)
98 warn("Cannot set buffer mode '%s' for %s", bufmode,
99 stream_name(s));
100 }
101
102 __attribute__ ((constructor)) static void
stdbuf(void)103 stdbuf(void)
104 {
105 char *i_mode, *o_mode, *e_mode;
106
107 i_mode = getenv("_STDBUF_I");
108 o_mode = getenv("_STDBUF_O");
109 e_mode = getenv("_STDBUF_E");
110
111 if (e_mode != NULL)
112 change_buf(stderr, e_mode);
113 if (i_mode != NULL)
114 change_buf(stdin, i_mode);
115 if (o_mode != NULL)
116 change_buf(stdout, o_mode);
117 }
118