xref: /freebsd/usr.bin/stdbuf/stdbuf.c (revision 6486b015fc84e96725fef22b0e3363351399ae83)
1 /*-
2  * Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <err.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <unistd.h>
33 
34 #define	LIBSTDBUF	"/usr/lib/libstdbuf.so"
35 
36 extern char *__progname;
37 
38 static void
39 usage(int s)
40 {
41 
42 	fprintf(stderr, "Usage: %s [-e 0|L|<sz>] [-i 0|L|<sz>] [-o 0|L|<sz>] "
43 	    "<cmd> [args ...]\n", __progname);
44 	exit(s);
45 }
46 
47 int
48 main(int argc, char *argv[])
49 {
50 	char *ibuf, *obuf, *ebuf;
51 	char *preload0, *preload1;
52 	int i;
53 
54 	ibuf = obuf = ebuf = NULL;
55 	while ((i = getopt(argc, argv, ":e:i:o:")) != -1) {
56 		switch (i) {
57 		case 'e':
58 			ebuf = optarg;
59 			break;
60 		case 'i':
61 			ibuf = optarg;
62 			break;
63 		case 'o':
64 			obuf = optarg;
65 			break;
66 		case ':':
67 			warnx("Missing argument for option -%c", optopt);
68 			usage(1);
69 			break;
70 		case '?':
71 		default:
72 			warnx("Unknown option: %c", optopt);
73 			usage(1);
74 			break;
75 		}
76 	}
77 	argc -= optind;
78 	argv += optind;
79 	if (argc < 2)
80 		usage(0);
81 
82 	if (ibuf != NULL && setenv("_STDBUF_I", ibuf, 1) == -1)
83 		warn("Failed to set environment variable: %s=%s",
84 		    "_STDBUF_I", ibuf);
85 	if (obuf != NULL && setenv("_STDBUF_O", obuf, 1) == -1)
86 		warn("Failed to set environment variable: %s=%s",
87 		    "_STDBUF_O", obuf);
88 	if (ebuf != NULL && setenv("_STDBUF_E", ebuf, 1) == -1)
89 		warn("Failed to set environment variable: %s=%s",
90 		    "_STDBUF_E", ebuf);
91 
92 	preload0 = getenv("LD_PRELOAD");
93 	if (preload0 == NULL)
94 		i = asprintf(&preload1, "LD_PRELOAD=" LIBSTDBUF);
95 	else
96 		i = asprintf(&preload1, "LD_PRELOAD=%s:%s", preload0,
97 		    LIBSTDBUF);
98 
99 	if (i < 0 || putenv(preload1) == -1)
100 		warn("Failed to set environment variable: %s", preload1);
101 
102 	execvp(argv[0], argv);
103 	err(2, "%s", argv[0]);
104 }
105