1/*	$OpenBSD: exec.c,v 1.18 2005/08/08 08:05:34 espie Exp $ */
2/*-
3 * Copyright (c) 1991, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/param.h>
32#include <sys/types.h>
33#include <sys/uio.h>
34#include <errno.h>
35#include <unistd.h>
36#include <limits.h>
37#include <stdlib.h>
38#include <string.h>
39#include <strings.h>
40#include <stdio.h>
41#include <paths.h>
42#include <stdarg.h>
43#include <alloca.h>
44
45extern char **environ;
46
47int
48execl(const char *name, const char *arg, ...)
49{
50	va_list ap;
51	char **argv;
52	int n;
53
54	va_start(ap, arg);
55	n = 1;
56	while (va_arg(ap, char *) != NULL)
57		n++;
58	va_end(ap);
59	argv = alloca((n + 1) * sizeof(*argv));
60	if (argv == NULL) {
61		errno = ENOMEM;
62		return (-1);
63	}
64	va_start(ap, arg);
65	n = 1;
66	argv[0] = (char *)arg;
67	while ((argv[n] = va_arg(ap, char *)) != NULL)
68		n++;
69	va_end(ap);
70	return (execve(name, argv, environ));
71}
72
73int
74execle(const char *name, const char *arg, ...)
75{
76	va_list ap;
77	char **argv, **envp;
78	int n;
79
80	va_start(ap, arg);
81	n = 1;
82	while (va_arg(ap, char *) != NULL)
83		n++;
84	va_end(ap);
85	argv = alloca((n + 1) * sizeof(*argv));
86	if (argv == NULL) {
87		errno = ENOMEM;
88		return (-1);
89	}
90	va_start(ap, arg);
91	n = 1;
92	argv[0] = (char *)arg;
93	while ((argv[n] = va_arg(ap, char *)) != NULL)
94		n++;
95	envp = va_arg(ap, char **);
96	va_end(ap);
97	return (execve(name, argv, envp));
98}
99
100int
101execlp(const char *name, const char *arg, ...)
102{
103	va_list ap;
104	char **argv;
105	int n;
106
107	va_start(ap, arg);
108	n = 1;
109	while (va_arg(ap, char *) != NULL)
110		n++;
111	va_end(ap);
112	argv = alloca((n + 1) * sizeof(*argv));
113	if (argv == NULL) {
114		errno = ENOMEM;
115		return (-1);
116	}
117	va_start(ap, arg);
118	n = 1;
119	argv[0] = (char *)arg;
120	while ((argv[n] = va_arg(ap, char *)) != NULL)
121		n++;
122	va_end(ap);
123	return (execvp(name, argv));
124}
125
126int
127execv(const char *name, char * const *argv)
128{
129	(void)execve(name, argv, environ);
130	return (-1);
131}
132
133int
134execvp(const char *name, char * const *argv)
135{
136	char **memp;
137	int cnt, lp, ln, len;
138	char *p;
139	int eacces = 0;
140	char *bp, *cur, *path, buf[MAXPATHLEN];
141
142	/*
143	 * Do not allow null name
144	 */
145	if (name == NULL || *name == '\0') {
146		errno = ENOENT;
147		return (-1);
148 	}
149
150	/* If it's an absolute or relative path name, it's easy. */
151	if (strchr(name, '/')) {
152		bp = (char *)name;
153		cur = path = NULL;
154		goto retry;
155	}
156	bp = buf;
157
158	/* Get the path we're searching. */
159	if (!(path = getenv("PATH")))
160		path = _PATH_DEFPATH;
161	len = strlen(path) + 1;
162	cur = alloca(len);
163	if (cur == NULL) {
164		errno = ENOMEM;
165		return (-1);
166	}
167	strlcpy(cur, path, len);
168	path = cur;
169	while ((p = strsep(&cur, ":"))) {
170		/*
171		 * It's a SHELL path -- double, leading and trailing colons
172		 * mean the current directory.
173		 */
174		if (!*p) {
175			p = ".";
176			lp = 1;
177		} else
178			lp = strlen(p);
179		ln = strlen(name);
180
181		/*
182		 * If the path is too long complain.  This is a possible
183		 * security issue; given a way to make the path too long
184		 * the user may execute the wrong program.
185		 */
186		if (lp + ln + 2 > (int)sizeof(buf)) {
187			struct iovec iov[3];
188
189			iov[0].iov_base = "execvp: ";
190			iov[0].iov_len = 8;
191			iov[1].iov_base = p;
192			iov[1].iov_len = lp;
193			iov[2].iov_base = ": path too long\n";
194			iov[2].iov_len = 16;
195			(void)writev(STDERR_FILENO, iov, 3);
196			continue;
197		}
198		memcpy(buf, p, lp);
199		buf[lp] = '/';
200		memcpy(buf + lp + 1, name, ln);
201		buf[lp + ln + 1] = '\0';
202
203retry:		(void)execve(bp, argv, environ);
204		switch(errno) {
205		case E2BIG:
206			goto done;
207		case EISDIR:
208		case ELOOP:
209		case ENAMETOOLONG:
210		case ENOENT:
211			break;
212		case ENOEXEC:
213			for (cnt = 0; argv[cnt]; ++cnt)
214				;
215			memp = alloca((cnt + 2) * sizeof(char *));
216			if (memp == NULL)
217				goto done;
218			memp[0] = "sh";
219			memp[1] = bp;
220			memcpy(memp + 2, argv + 1, cnt * sizeof(char *));
221			(void)execve(_PATH_BSHELL, memp, environ);
222			goto done;
223		case ENOMEM:
224			goto done;
225		case ENOTDIR:
226			break;
227		case ETXTBSY:
228			/*
229			 * We used to retry here, but sh(1) doesn't.
230			 */
231			goto done;
232		case EACCES:
233			eacces = 1;
234			break;
235		default:
236			goto done;
237		}
238	}
239	if (eacces)
240		errno = EACCES;
241	else if (!errno)
242		errno = ENOENT;
243done:
244	return (-1);
245}
246