stdbuf.c revision 234772 
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: head/usr.bin/stdbuf/stdbuf.c 234772 2012-04-28 20:52:20Z jlh $
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
36extern char *__progname;
37
38static void
39usage(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
47int
48main(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