1 /* $NetBSD: execvp.c,v 1.31 2014/09/26 19:28:03 christos Exp $ */
2
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 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: execvp.c,v 1.31 2014/09/26 19:28:03 christos Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include "namespace.h"
42 #include <assert.h>
43 #include <errno.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <limits.h>
48 #include <unistd.h>
49 #include <paths.h>
50 #include "reentrant.h"
51
52 #ifdef __weak_alias
__weak_alias(execvp,_execvp)53 __weak_alias(execvp,_execvp)
54 __weak_alias(execvpe,_execvpe)
55 #endif
56
57 int
58 execvpe(const char *name, char * const *argv, char * const * envp)
59 {
60 const char **memp;
61 int cnt;
62 size_t lp, ln;
63 int eacces = 0;
64 unsigned int etxtbsy = 0;
65 char buf[PATH_MAX];
66 const char *bp, *path, *p;
67
68 _DIAGASSERT(name != NULL);
69
70 /* "" is not a valid filename; check this before traversing PATH. */
71 if (name[0] == '\0') {
72 errno = ENOENT;
73 goto done;
74 }
75 ln = strlen(name);
76 /* If it's an absolute or relative path name, it's easy. */
77 if (strchr(name, '/')) {
78 bp = name;
79 path = "";
80 goto retry;
81 }
82 bp = buf;
83
84 /* Get the path we're searching. */
85 if (!(path = getenv("PATH")))
86 path = _PATH_DEFPATH;
87
88 do {
89 /* Find the end of this path element. */
90 for (p = path; *path != 0 && *path != ':'; path++)
91 continue;
92 /*
93 * It's a SHELL path -- double, leading and trailing colons
94 * mean the current directory.
95 */
96 if (p == path) {
97 p = ".";
98 lp = 1;
99 } else
100 lp = path - p;
101
102 /*
103 * If the path is too long complain. This is a possible
104 * security issue; given a way to make the path too long
105 * the user may execute the wrong program.
106 */
107 if (lp + ln + 2 > sizeof(buf)) {
108 (void)write(STDERR_FILENO, "execvp: ", 8);
109 (void)write(STDERR_FILENO, p, lp);
110 (void)write(STDERR_FILENO, ": path too long\n", 16);
111 continue;
112 }
113 memcpy(buf, p, lp);
114 buf[lp] = '/';
115 memcpy(buf + lp + 1, name, ln);
116 buf[lp + ln + 1] = '\0';
117
118 retry: (void)execve(bp, argv, envp);
119 switch (errno) {
120 case EACCES:
121 eacces = 1;
122 break;
123 case ENOTDIR:
124 case ENOENT:
125 break;
126 case ENOEXEC:
127 for (cnt = 0; argv[cnt] != NULL; ++cnt)
128 continue;
129 /*
130 * we can't use malloc here because, if we are doing
131 * vfork+exec, it leaks memory in the parent.
132 */
133 if ((memp = alloca((cnt + 2) * sizeof(*memp))) == NULL)
134 goto done;
135 memp[0] = _PATH_BSHELL;
136 memp[1] = bp;
137 (void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp));
138 (void)execve(_PATH_BSHELL, __UNCONST(memp), envp);
139 goto done;
140 case ETXTBSY:
141 if (etxtbsy < 3)
142 (void)sleep(++etxtbsy);
143 goto retry;
144 default:
145 goto done;
146 }
147 } while (*path++ == ':'); /* Otherwise, *path was NUL */
148 if (eacces)
149 errno = EACCES;
150 else if (!errno)
151 errno = ENOENT;
152 done:
153 return (-1);
154 }
155
156 extern char **environ;
157
158 int
execvp(const char * name,char * const * argv)159 execvp(const char *name, char * const *argv)
160 {
161 return execvpe(name, argv, environ);
162 }
163