xref: /freebsd/usr.bin/stdbuf/stdbuf.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 <stdio.h>
33 #include <stdlib.h>
34 #include <unistd.h>
35 
36 #define	LIBSTDBUF	"/usr/lib/libstdbuf.so"
37 #define	LIBSTDBUF32	"/usr/lib32/libstdbuf.so"
38 
39 extern char *__progname;
40 
41 static void
42 usage(int s)
43 {
44 
45 	fprintf(stderr, "Usage: %s [-e 0|L|B|<sz>] [-i 0|L|B|<sz>] [-o 0|L|B|<sz>] "
46 	    "<cmd> [args ...]\n", __progname);
47 	exit(s);
48 }
49 
50 int
51 main(int argc, char *argv[])
52 {
53 	char *ibuf, *obuf, *ebuf;
54 	char *preload0, *preload1;
55 	int i;
56 
57 	ibuf = obuf = ebuf = NULL;
58 	while ((i = getopt(argc, argv, "e:i:o:")) != -1) {
59 		switch (i) {
60 		case 'e':
61 			ebuf = optarg;
62 			break;
63 		case 'i':
64 			ibuf = optarg;
65 			break;
66 		case 'o':
67 			obuf = optarg;
68 			break;
69 		case '?':
70 		default:
71 			usage(1);
72 			break;
73 		}
74 	}
75 	argc -= optind;
76 	argv += optind;
77 	if (argc == 0)
78 		exit(0);
79 
80 	if (ibuf != NULL && setenv("_STDBUF_I", ibuf, 1) == -1)
81 		warn("Failed to set environment variable: %s=%s",
82 		    "_STDBUF_I", ibuf);
83 	if (obuf != NULL && setenv("_STDBUF_O", obuf, 1) == -1)
84 		warn("Failed to set environment variable: %s=%s",
85 		    "_STDBUF_O", obuf);
86 	if (ebuf != NULL && setenv("_STDBUF_E", ebuf, 1) == -1)
87 		warn("Failed to set environment variable: %s=%s",
88 		    "_STDBUF_E", ebuf);
89 
90 	preload0 = getenv("LD_PRELOAD");
91 	if (preload0 == NULL)
92 		i = asprintf(&preload1, "LD_PRELOAD=" LIBSTDBUF);
93 	else
94 		i = asprintf(&preload1, "LD_PRELOAD=%s:%s", preload0,
95 		    LIBSTDBUF);
96 
97 	if (i < 0 || putenv(preload1) == -1)
98 		warn("Failed to set environment variable: LD_PRELOAD");
99 
100 	preload0 = getenv("LD_32_PRELOAD");
101 	if (preload0 == NULL)
102 		i = asprintf(&preload1, "LD_32_PRELOAD=" LIBSTDBUF32);
103 	else
104 		i = asprintf(&preload1, "LD_32_PRELOAD=%s:%s", preload0,
105 		    LIBSTDBUF32);
106 
107 	if (i < 0 || putenv(preload1) == -1)
108 		warn("Failed to set environment variable: LD_32_PRELOAD");
109 
110 	execvp(argv[0], argv);
111 	err(2, "%s", argv[0]);
112 }
113