xref: /freebsd/usr.bin/env/env.c (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 1993, 1994
5  *	The Regents of the University of California.  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  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/types.h>
33 
34 #include <err.h>
35 #include <errno.h>
36 #include <login_cap.h>
37 #include <pwd.h>
38 #include <stdbool.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 
44 #include "envopts.h"
45 
46 extern char **environ;
47 
48 int	 env_verbosity;
49 
50 static void usage(void) __dead2;
51 
52 /*
53  * Exit codes.
54  */
55 #define EXIT_CANCELED      125 /* Internal error prior to exec attempt. */
56 #define EXIT_CANNOT_INVOKE 126 /* Program located, but not usable. */
57 #define EXIT_ENOENT        127 /* Could not find program to exec. */
58 
59 int
60 main(int argc, char **argv)
61 {
62 	char *altpath, **ep, *p, **parg, term;
63 	char *cleanenv[1];
64 	char *login_class, *login_name;
65 	struct passwd *pw;
66 	login_cap_t *lc;
67 	bool login_as_user;
68 	uid_t uid;
69 	int ch, want_clear;
70 	int rtrn;
71 
72 	altpath = NULL;
73 	login_class = NULL;
74 	login_name = NULL;
75 	pw = NULL;
76 	lc = NULL;
77 	login_as_user = false;
78 	want_clear = 0;
79 	term = '\n';
80 	while ((ch = getopt(argc, argv, "-0iL:P:S:U:u:v")) != -1)
81 		switch(ch) {
82 		case '-':
83 		case 'i':
84 			want_clear = 1;
85 			break;
86 		case '0':
87 			term = '\0';
88 			break;
89 		case 'U':
90 			login_as_user = true;
91 			/* FALLTHROUGH */
92 		case 'L':
93 			login_name = optarg;
94 			break;
95 		case 'P':
96 			altpath = strdup(optarg);
97 			break;
98 		case 'S':
99 			/*
100 			 * The -S option, for "split string on spaces, with
101 			 * support for some simple substitutions"...
102 			 */
103 			split_spaces(optarg, &optind, &argc, &argv);
104 			break;
105 		case 'u':
106 			if (env_verbosity)
107 				fprintf(stderr, "#env unset:\t%s\n", optarg);
108 			rtrn = unsetenv(optarg);
109 			if (rtrn == -1)
110 				err(EXIT_FAILURE, "unsetenv %s", optarg);
111 			break;
112 		case 'v':
113 			env_verbosity++;
114 			if (env_verbosity > 1)
115 				fprintf(stderr, "#env verbosity now at %d\n",
116 				    env_verbosity);
117 			break;
118 		case '?':
119 		default:
120 			usage();
121 		}
122 	if (want_clear) {
123 		environ = cleanenv;
124 		cleanenv[0] = NULL;
125 		if (env_verbosity)
126 			fprintf(stderr, "#env clearing environ\n");
127 	}
128 	if (login_name != NULL) {
129 		login_class = strchr(login_name, '/');
130 		if (login_class)
131 			*login_class++ = '\0';
132 		if (*login_name != '\0' && strcmp(login_name, "-") != 0) {
133 			pw = getpwnam(login_name);
134 			if (pw == NULL) {
135 				char *endp = NULL;
136 				errno = 0;
137 				uid = strtoul(login_name, &endp, 10);
138 				if (errno == 0 && *endp == '\0')
139 					pw = getpwuid(uid);
140 			}
141 			if (pw == NULL)
142 				errx(EXIT_FAILURE, "no such user: %s", login_name);
143 		}
144 		/*
145 		 * Note that it is safe for pw to be null here; the libutil
146 		 * code handles that, bypassing substitution of $ and using
147 		 * the class "default" if no class name is given either.
148 		 */
149 		if (login_class != NULL) {
150 			lc = login_getclass(login_class);
151 			if (lc == NULL)
152 				errx(EXIT_FAILURE, "no such login class: %s",
153 				    login_class);
154 		} else {
155 			lc = login_getpwclass(pw);
156 			if (lc == NULL)
157 				errx(EXIT_FAILURE, "login_getpwclass failed");
158 		}
159 
160 		/*
161 		 * This is not done with setusercontext() because that will
162 		 * try and use ~/.login_conf even when we don't want it to.
163 		 */
164 		setclassenvironment(lc, pw, 1);
165 		setclassenvironment(lc, pw, 0);
166 		if (login_as_user) {
167 			login_close(lc);
168 			if ((lc = login_getuserclass(pw)) != NULL) {
169 				setclassenvironment(lc, pw, 1);
170 				setclassenvironment(lc, pw, 0);
171 			}
172 		}
173 		endpwent();
174 		if (lc != NULL)
175 			login_close(lc);
176 	}
177 	for (argv += optind; *argv && (p = strchr(*argv, '=')); ++argv) {
178 		if (env_verbosity)
179 			fprintf(stderr, "#env setenv:\t%s\n", *argv);
180 		*p = '\0';
181 		rtrn = setenv(*argv, p + 1, 1);
182 		*p = '=';
183 		if (rtrn == -1)
184 			err(EXIT_FAILURE, "setenv %s", *argv);
185 	}
186 	if (*argv) {
187 		if (term == '\0')
188 			errx(EXIT_CANCELED, "cannot specify command with -0");
189 		if (altpath)
190 			search_paths(altpath, argv);
191 		if (env_verbosity) {
192 			fprintf(stderr, "#env executing:\t%s\n", *argv);
193 			for (parg = argv, argc = 0; *parg; parg++, argc++)
194 				fprintf(stderr, "#env    arg[%d]=\t'%s'\n",
195 				    argc, *parg);
196 			if (env_verbosity > 1)
197 				sleep(1);
198 		}
199 		execvp(*argv, argv);
200 		err(errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE,
201 		    "%s", *argv);
202 	}
203 	for (ep = environ; *ep; ep++)
204 		(void)printf("%s%c", *ep, term);
205 	exit(0);
206 }
207 
208 static void
209 usage(void)
210 {
211 	(void)fprintf(stderr,
212 	    "usage: env [-0iv] [-L|-U user[/class]] [-P utilpath] [-S string] [-u name]\n"
213 	    "           [name=value ...] [utility [argument ...]]\n");
214 	exit(1);
215 }
216