1 /* $OpenBSD: exec.c,v 1.21 2013/09/30 12:02:33 millert 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/types.h>
32 #include <sys/uio.h>
33
34 #include <errno.h>
35 #include <limits.h>
36 #include <paths.h>
37 #include <stdarg.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42
43 extern char **environ;
44
45 int
execl(const char * name,const char * arg,...)46 execl(const char *name, const char *arg, ...)
47 {
48 va_list ap;
49 char **argv;
50 int n;
51
52 va_start(ap, arg);
53 n = 1;
54 while (va_arg(ap, char *) != NULL)
55 n++;
56 va_end(ap);
57 argv = alloca((n + 1) * sizeof(*argv));
58 if (argv == NULL) {
59 errno = ENOMEM;
60 return (-1);
61 }
62 va_start(ap, arg);
63 n = 1;
64 argv[0] = (char *)arg;
65 while ((argv[n] = va_arg(ap, char *)) != NULL)
66 n++;
67 va_end(ap);
68 return (execve(name, argv, environ));
69 }
70
71 int
execle(const char * name,const char * arg,...)72 execle(const char *name, const char *arg, ...)
73 {
74 va_list ap;
75 char **argv, **envp;
76 int n;
77
78 va_start(ap, arg);
79 n = 1;
80 while (va_arg(ap, char *) != NULL)
81 n++;
82 va_end(ap);
83 argv = alloca((n + 1) * sizeof(*argv));
84 if (argv == NULL) {
85 errno = ENOMEM;
86 return (-1);
87 }
88 va_start(ap, arg);
89 n = 1;
90 argv[0] = (char *)arg;
91 while ((argv[n] = va_arg(ap, char *)) != NULL)
92 n++;
93 envp = va_arg(ap, char **);
94 va_end(ap);
95 return (execve(name, argv, envp));
96 }
97
98 int
execlp(const char * name,const char * arg,...)99 execlp(const char *name, const char *arg, ...)
100 {
101 va_list ap;
102 char **argv;
103 int n;
104
105 va_start(ap, arg);
106 n = 1;
107 while (va_arg(ap, char *) != NULL)
108 n++;
109 va_end(ap);
110 argv = alloca((n + 1) * sizeof(*argv));
111 if (argv == NULL) {
112 errno = ENOMEM;
113 return (-1);
114 }
115 va_start(ap, arg);
116 n = 1;
117 argv[0] = (char *)arg;
118 while ((argv[n] = va_arg(ap, char *)) != NULL)
119 n++;
120 va_end(ap);
121 return (execvp(name, argv));
122 }
123
124 int
execv(const char * name,char * const * argv)125 execv(const char *name, char *const *argv)
126 {
127 (void)execve(name, argv, environ);
128 return (-1);
129 }
130
131 int
execvpe(const char * name,char * const * argv,char * const * envp)132 execvpe(const char *name, char *const *argv, char *const *envp)
133 {
134 char **memp;
135 int cnt;
136 size_t lp, ln, len;
137 char *p;
138 int eacces = 0;
139 char *bp, *cur, *path, buf[PATH_MAX];
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 > 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, envp);
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, envp);
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
246 int
execvp(const char * name,char * const * argv)247 execvp(const char *name, char *const *argv)
248 {
249 return execvpe(name, argv, environ);
250 }
251
252