xref: /freebsd/usr.bin/env/env.c (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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, *altwd, **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 	altwd = NULL;
74 	login_class = NULL;
75 	login_name = NULL;
76 	pw = NULL;
77 	lc = NULL;
78 	login_as_user = false;
79 	want_clear = 0;
80 	term = '\n';
81 	while ((ch = getopt(argc, argv, "-0C:iL:P:S:U:u:v")) != -1)
82 		switch(ch) {
83 		case '-':
84 		case 'i':
85 			want_clear = 1;
86 			break;
87 		case '0':
88 			term = '\0';
89 			break;
90 		case 'C':
91 			altwd = optarg;
92 			break;
93 		case 'U':
94 			login_as_user = true;
95 			/* FALLTHROUGH */
96 		case 'L':
97 			login_name = optarg;
98 			break;
99 		case 'P':
100 			altpath = optarg;
101 			break;
102 		case 'S':
103 			/*
104 			 * The -S option, for "split string on spaces, with
105 			 * support for some simple substitutions"...
106 			 */
107 			split_spaces(optarg, &optind, &argc, &argv);
108 			break;
109 		case 'u':
110 			if (env_verbosity)
111 				fprintf(stderr, "#env unset:\t%s\n", optarg);
112 			rtrn = unsetenv(optarg);
113 			if (rtrn == -1)
114 				err(EXIT_FAILURE, "unsetenv %s", optarg);
115 			break;
116 		case 'v':
117 			env_verbosity++;
118 			if (env_verbosity > 1)
119 				fprintf(stderr, "#env verbosity now at %d\n",
120 				    env_verbosity);
121 			break;
122 		case '?':
123 		default:
124 			usage();
125 		}
126 	if (want_clear) {
127 		environ = cleanenv;
128 		cleanenv[0] = NULL;
129 		if (env_verbosity)
130 			fprintf(stderr, "#env clearing environ\n");
131 	}
132 	if (login_name != NULL) {
133 		login_class = strchr(login_name, '/');
134 		if (login_class)
135 			*login_class++ = '\0';
136 		if (*login_name != '\0' && strcmp(login_name, "-") != 0) {
137 			pw = getpwnam(login_name);
138 			if (pw == NULL) {
139 				char *endp = NULL;
140 				errno = 0;
141 				uid = strtoul(login_name, &endp, 10);
142 				if (errno == 0 && *endp == '\0')
143 					pw = getpwuid(uid);
144 			}
145 			if (pw == NULL)
146 				errx(EXIT_FAILURE, "no such user: %s", login_name);
147 		}
148 		/*
149 		 * Note that it is safe for pw to be null here; the libutil
150 		 * code handles that, bypassing substitution of $ and using
151 		 * the class "default" if no class name is given either.
152 		 */
153 		if (login_class != NULL) {
154 			lc = login_getclass(login_class);
155 			if (lc == NULL)
156 				errx(EXIT_FAILURE, "no such login class: %s",
157 				    login_class);
158 		} else {
159 			lc = login_getpwclass(pw);
160 			if (lc == NULL)
161 				errx(EXIT_FAILURE, "login_getpwclass failed");
162 		}
163 
164 		/*
165 		 * This is not done with setusercontext() because that will
166 		 * try and use ~/.login_conf even when we don't want it to.
167 		 */
168 		setclassenvironment(lc, pw, 1);
169 		setclassenvironment(lc, pw, 0);
170 		if (login_as_user) {
171 			login_close(lc);
172 			if ((lc = login_getuserclass(pw)) != NULL) {
173 				setclassenvironment(lc, pw, 1);
174 				setclassenvironment(lc, pw, 0);
175 			}
176 		}
177 		endpwent();
178 		if (lc != NULL)
179 			login_close(lc);
180 	}
181 	for (argv += optind; *argv && (p = strchr(*argv, '=')); ++argv) {
182 		if (env_verbosity)
183 			fprintf(stderr, "#env setenv:\t%s\n", *argv);
184 		*p = '\0';
185 		rtrn = setenv(*argv, p + 1, 1);
186 		*p = '=';
187 		if (rtrn == -1)
188 			err(EXIT_FAILURE, "setenv %s", *argv);
189 	}
190 	if (*argv) {
191 		if (term == '\0')
192 			errx(EXIT_CANCELED, "cannot specify command with -0");
193 		if (altwd && chdir(altwd) != 0)
194 			err(EXIT_CANCELED, "cannot change directory to '%s'",
195 			    altwd);
196 		if (altpath)
197 			search_paths(altpath, argv);
198 		if (env_verbosity) {
199 			fprintf(stderr, "#env executing:\t%s\n", *argv);
200 			for (parg = argv, argc = 0; *parg; parg++, argc++)
201 				fprintf(stderr, "#env    arg[%d]=\t'%s'\n",
202 				    argc, *parg);
203 			if (env_verbosity > 1)
204 				sleep(1);
205 		}
206 		execvp(*argv, argv);
207 		err(errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE,
208 		    "%s", *argv);
209 	} else {
210 		if (altwd)
211 			errx(EXIT_CANCELED, "must specify command with -C");
212 		if (altpath)
213 			errx(EXIT_CANCELED, "must specify command with -P");
214 	}
215 	for (ep = environ; *ep; ep++)
216 		(void)printf("%s%c", *ep, term);
217 	if (fflush(stdout) != 0)
218 		err(1, "stdout");
219 	exit(0);
220 }
221 
222 static void
223 usage(void)
224 {
225 	(void)fprintf(stderr,
226 	    "usage: env [-0iv] [-C workdir] [-L|-U user[/class]] [-P utilpath] [-S string]\n"
227 	    "           [-u name] [name=value ...] [utility [argument ...]]\n");
228 	exit(1);
229 }
230