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 <stdio.h>
40 #include <paths.h>
41 #include <stdarg.h>
42 #include <alloca.h>
43
44 extern char **environ;
45
46 int
execl(const char * name,const char * arg,...)47 execl(const char *name, const char *arg, ...)
48 {
49 va_list ap;
50 char **argv;
51 int n;
52
53 va_start(ap, arg);
54 n = 1;
55 while (va_arg(ap, char *) != NULL)
56 n++;
57 va_end(ap);
58 argv = alloca((n + 1) * sizeof(*argv));
59 if (argv == NULL) {
60 errno = ENOMEM;
61 return (-1);
62 }
63 va_start(ap, arg);
64 n = 1;
65 argv[0] = (char *)arg;
66 while ((argv[n] = va_arg(ap, char *)) != NULL)
67 n++;
68 va_end(ap);
69 return (execve(name, argv, environ));
70 }
71
72 int
execle(const char * name,const char * arg,...)73 execle(const char *name, const char *arg, ...)
74 {
75 va_list ap;
76 char **argv, **envp;
77 int n;
78
79 va_start(ap, arg);
80 n = 1;
81 while (va_arg(ap, char *) != NULL)
82 n++;
83 va_end(ap);
84 argv = alloca((n + 1) * sizeof(*argv));
85 if (argv == NULL) {
86 errno = ENOMEM;
87 return (-1);
88 }
89 va_start(ap, arg);
90 n = 1;
91 argv[0] = (char *)arg;
92 while ((argv[n] = va_arg(ap, char *)) != NULL)
93 n++;
94 envp = va_arg(ap, char **);
95 va_end(ap);
96 return (execve(name, argv, envp));
97 }
98
99 int
execlp(const char * name,const char * arg,...)100 execlp(const char *name, const char *arg, ...)
101 {
102 va_list ap;
103 char **argv;
104 int n;
105
106 va_start(ap, arg);
107 n = 1;
108 while (va_arg(ap, char *) != NULL)
109 n++;
110 va_end(ap);
111 argv = alloca((n + 1) * sizeof(*argv));
112 if (argv == NULL) {
113 errno = ENOMEM;
114 return (-1);
115 }
116 va_start(ap, arg);
117 n = 1;
118 argv[0] = (char *)arg;
119 while ((argv[n] = va_arg(ap, char *)) != NULL)
120 n++;
121 va_end(ap);
122 return (execvp(name, argv));
123 }
124
125 int
execv(const char * name,char * const * argv)126 execv(const char *name, char * const *argv)
127 {
128 (void)execve(name, argv, environ);
129 return (-1);
130 }
131
132 int
execvp(const char * name,char * const * argv)133 execvp(const char *name, char * const *argv)
134 {
135 char **memp;
136 int cnt, lp, ln, len;
137 char *p;
138 int eacces = 0;
139 char *bp, *cur, *path, buf[MAXPATHLEN];
140
141 /*
142 * Do not allow null name
143 */
144 if (name == NULL || *name == '\0') {
145 errno = ENOENT;
146 return (-1);
147 }
148
149 /* If it's an absolute or relative path name, it's easy. */
150 if (strchr(name, '/')) {
151 bp = (char *)name;
152 cur = path = NULL;
153 goto retry;
154 }
155 bp = buf;
156
157 /* Get the path we're searching. */
158 if (!(path = getenv("PATH")))
159 path = _PATH_DEFPATH;
160 len = strlen(path) + 1;
161 cur = alloca(len);
162 if (cur == NULL) {
163 errno = ENOMEM;
164 return (-1);
165 }
166 strlcpy(cur, path, len);
167 path = cur;
168 while ((p = strsep(&cur, ":"))) {
169 /*
170 * It's a SHELL path -- double, leading and trailing colons
171 * mean the current directory.
172 */
173 if (!*p) {
174 p = ".";
175 lp = 1;
176 } else
177 lp = strlen(p);
178 ln = strlen(name);
179
180 /*
181 * If the path is too long complain. This is a possible
182 * security issue; given a way to make the path too long
183 * the user may execute the wrong program.
184 */
185 if (lp + ln + 2 > (int)sizeof(buf)) {
186 struct iovec iov[3];
187
188 iov[0].iov_base = "execvp: ";
189 iov[0].iov_len = 8;
190 iov[1].iov_base = p;
191 iov[1].iov_len = lp;
192 iov[2].iov_base = ": path too long\n";
193 iov[2].iov_len = 16;
194 (void)writev(STDERR_FILENO, iov, 3);
195 continue;
196 }
197 bcopy(p, buf, lp);
198 buf[lp] = '/';
199 bcopy(name, buf + lp + 1, ln);
200 buf[lp + ln + 1] = '\0';
201
202 retry: (void)execve(bp, argv, environ);
203 switch(errno) {
204 case E2BIG:
205 goto done;
206 case EISDIR:
207 case ELOOP:
208 case ENAMETOOLONG:
209 case ENOENT:
210 break;
211 case ENOEXEC:
212 for (cnt = 0; argv[cnt]; ++cnt)
213 ;
214 memp = alloca((cnt + 2) * sizeof(char *));
215 if (memp == NULL)
216 goto done;
217 memp[0] = "sh";
218 memp[1] = bp;
219 bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
220 (void)execve(_PATH_BSHELL, memp, environ);
221 goto done;
222 case ENOMEM:
223 goto done;
224 case ENOTDIR:
225 break;
226 case ETXTBSY:
227 /*
228 * We used to retry here, but sh(1) doesn't.
229 */
230 goto done;
231 case EACCES:
232 eacces = 1;
233 break;
234 default:
235 goto done;
236 }
237 }
238 if (eacces)
239 errno = EACCES;
240 else if (!errno)
241 errno = ENOENT;
242 done:
243 return (-1);
244 }
245