1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993
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/cdefs.h>
33 __SCCSID("@(#)exec.c 8.1 (Berkeley) 6/4/93");
34 __FBSDID("$FreeBSD$");
35
36 #include "namespace.h"
37 #include <sys/param.h>
38 #include <sys/stat.h>
39 #include <errno.h>
40 #include <unistd.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <stdio.h>
44 #include <paths.h>
45
46 #include <stdarg.h>
47 #include "un-namespace.h"
48 #include "libc_private.h"
49
50 extern char **environ;
51
52 static const char execvPe_err_preamble[] = "execvP: ";
53 static const char execvPe_err_trailer[] = ": path too long\n";
54
55 int
execl(const char * name,const char * arg,...)56 execl(const char *name, const char *arg, ...)
57 {
58 va_list ap;
59 const char **argv;
60 int n;
61
62 va_start(ap, arg);
63 n = 1;
64 while (va_arg(ap, char *) != NULL)
65 n++;
66 va_end(ap);
67 argv = alloca((n + 1) * sizeof(*argv));
68 if (argv == NULL) {
69 errno = ENOMEM;
70 return (-1);
71 }
72 va_start(ap, arg);
73 n = 1;
74 argv[0] = arg;
75 while ((argv[n] = va_arg(ap, char *)) != NULL)
76 n++;
77 va_end(ap);
78 return (_execve(name, __DECONST(char **, argv), environ));
79 }
80
81 int
execle(const char * name,const char * arg,...)82 execle(const char *name, const char *arg, ...)
83 {
84 va_list ap;
85 const char **argv;
86 char **envp;
87 int n;
88
89 va_start(ap, arg);
90 n = 1;
91 while (va_arg(ap, char *) != NULL)
92 n++;
93 va_end(ap);
94 argv = alloca((n + 1) * sizeof(*argv));
95 if (argv == NULL) {
96 errno = ENOMEM;
97 return (-1);
98 }
99 va_start(ap, arg);
100 n = 1;
101 argv[0] = arg;
102 while ((argv[n] = va_arg(ap, char *)) != NULL)
103 n++;
104 envp = va_arg(ap, char **);
105 va_end(ap);
106 return (_execve(name, __DECONST(char **, argv), envp));
107 }
108
109 int
execlp(const char * name,const char * arg,...)110 execlp(const char *name, const char *arg, ...)
111 {
112 va_list ap;
113 const char **argv;
114 int n;
115
116 va_start(ap, arg);
117 n = 1;
118 while (va_arg(ap, char *) != NULL)
119 n++;
120 va_end(ap);
121 argv = alloca((n + 1) * sizeof(*argv));
122 if (argv == NULL) {
123 errno = ENOMEM;
124 return (-1);
125 }
126 va_start(ap, arg);
127 n = 1;
128 argv[0] = arg;
129 while ((argv[n] = va_arg(ap, char *)) != NULL)
130 n++;
131 va_end(ap);
132 return (execvp(name, __DECONST(char **, argv)));
133 }
134
135 int
execv(const char * name,char * const * argv)136 execv(const char *name, char * const *argv)
137 {
138 (void)_execve(name, argv, environ);
139 return (-1);
140 }
141
142 int
execvp(const char * name,char * const * argv)143 execvp(const char *name, char * const *argv)
144 {
145 return (_execvpe(name, argv, environ));
146 }
147
148 static int
execvPe(const char * name,const char * path,char * const * argv,char * const * envp)149 execvPe(const char *name, const char *path, char * const *argv,
150 char * const *envp)
151 {
152 const char **memp;
153 size_t cnt, lp, ln;
154 int eacces, save_errno;
155 char buf[MAXPATHLEN];
156 const char *bp, *np, *op, *p;
157 struct stat sb;
158
159 eacces = 0;
160
161 /* If it's an absolute or relative path name, it's easy. */
162 if (strchr(name, '/')) {
163 bp = name;
164 op = NULL;
165 goto retry;
166 }
167 bp = buf;
168
169 /* If it's an empty path name, fail in the usual POSIX way. */
170 if (*name == '\0') {
171 errno = ENOENT;
172 return (-1);
173 }
174
175 op = path;
176 ln = strlen(name);
177 while (op != NULL) {
178 np = strchrnul(op, ':');
179
180 /*
181 * It's a SHELL path -- double, leading and trailing colons
182 * mean the current directory.
183 */
184 if (np == op) {
185 /* Empty component. */
186 p = ".";
187 lp = 1;
188 } else {
189 /* Non-empty component. */
190 p = op;
191 lp = np - op;
192 }
193
194 /* Advance to the next component or terminate after this. */
195 if (*np == '\0')
196 op = NULL;
197 else
198 op = np + 1;
199
200 /*
201 * If the path is too long complain. This is a possible
202 * security issue; given a way to make the path too long
203 * the user may execute the wrong program.
204 */
205 if (lp + ln + 2 > sizeof(buf)) {
206 (void)_write(STDERR_FILENO, execvPe_err_preamble,
207 sizeof(execvPe_err_preamble) - 1);
208 (void)_write(STDERR_FILENO, p, lp);
209 (void)_write(STDERR_FILENO, execvPe_err_trailer,
210 sizeof(execvPe_err_trailer) - 1);
211 continue;
212 }
213 bcopy(p, buf, lp);
214 buf[lp] = '/';
215 bcopy(name, buf + lp + 1, ln);
216 buf[lp + ln + 1] = '\0';
217
218 retry: (void)_execve(bp, argv, envp);
219 switch (errno) {
220 case E2BIG:
221 goto done;
222 case ELOOP:
223 case ENAMETOOLONG:
224 case ENOENT:
225 break;
226 case ENOEXEC:
227 for (cnt = 0; argv[cnt]; ++cnt)
228 ;
229
230 /*
231 * cnt may be 0 above; always allocate at least
232 * 3 entries so that we can at least fit "sh", bp, and
233 * the NULL terminator. We can rely on cnt to take into
234 * account the NULL terminator in all other scenarios,
235 * as we drop argv[0].
236 */
237 memp = alloca(MAX(3, cnt + 2) * sizeof(char *));
238 if (memp == NULL) {
239 /* errno = ENOMEM; XXX override ENOEXEC? */
240 goto done;
241 }
242 if (cnt > 0) {
243 memp[0] = argv[0];
244 memp[1] = bp;
245 bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
246 } else {
247 memp[0] = "sh";
248 memp[1] = bp;
249 memp[2] = NULL;
250 }
251 (void)_execve(_PATH_BSHELL,
252 __DECONST(char **, memp), envp);
253 goto done;
254 case ENOMEM:
255 goto done;
256 case ENOTDIR:
257 break;
258 case ETXTBSY:
259 /*
260 * We used to retry here, but sh(1) doesn't.
261 */
262 goto done;
263 default:
264 /*
265 * EACCES may be for an inaccessible directory or
266 * a non-executable file. Call stat() to decide
267 * which. This also handles ambiguities for EFAULT
268 * and EIO, and undocumented errors like ESTALE.
269 * We hope that the race for a stat() is unimportant.
270 */
271 save_errno = errno;
272 if (stat(bp, &sb) != 0)
273 break;
274 if (save_errno == EACCES) {
275 eacces = 1;
276 continue;
277 }
278 errno = save_errno;
279 goto done;
280 }
281 }
282 if (eacces)
283 errno = EACCES;
284 else
285 errno = ENOENT;
286 done:
287 return (-1);
288 }
289
290 int
execvP(const char * name,const char * path,char * const argv[])291 execvP(const char *name, const char *path, char * const argv[])
292 {
293 return execvPe(name, path, argv, environ);
294 }
295
296 int
_execvpe(const char * name,char * const argv[],char * const envp[])297 _execvpe(const char *name, char * const argv[], char * const envp[])
298 {
299 const char *path;
300
301 /* Get the path we're searching. */
302 if ((path = getenv("PATH")) == NULL)
303 path = _PATH_DEFPATH;
304
305 return (execvPe(name, path, argv, envp));
306 }
307