1 /* $NetBSD: execvp.c,v 1.32 2024/01/20 14:52:47 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 1.32 2024/01/20 14:52:47 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 #include "extern.h"
52
53 #ifdef __weak_alias
__weak_alias(execvp,_execvp)54 __weak_alias(execvp,_execvp)
55 __weak_alias(execvpe,_execvpe)
56 #endif
57
58 int
59 execvpe(const char *name, char * const *argv, char * const * envp)
60 {
61 const char **memp;
62 int cnt;
63 size_t lp, ln;
64 int eacces = 0;
65 unsigned int etxtbsy = 0;
66 char buf[PATH_MAX];
67 const char *bp, *path, *p;
68
69 _DIAGASSERT(name != NULL);
70
71 /* "" is not a valid filename; check this before traversing PATH. */
72 if (name[0] == '\0') {
73 errno = ENOENT;
74 goto done;
75 }
76 ln = strlen(name);
77 /* If it's an absolute or relative path name, it's easy. */
78 if (strchr(name, '/')) {
79 bp = name;
80 path = "";
81 goto retry;
82 }
83 bp = buf;
84
85 /* Get the path we're searching. */
86 if (!(path = getenv("PATH")))
87 path = _PATH_DEFPATH;
88
89 do {
90 /* Find the end of this path element. */
91 for (p = path; *path != 0 && *path != ':'; path++)
92 continue;
93 /*
94 * It's a SHELL path -- double, leading and trailing colons
95 * mean the current directory.
96 */
97 if (p == path) {
98 p = ".";
99 lp = 1;
100 } else
101 lp = path - p;
102
103 /*
104 * If the path is too long complain. This is a possible
105 * security issue; given a way to make the path too long
106 * the user may execute the wrong program.
107 */
108 if (lp + ln + 2 > sizeof(buf)) {
109 (void)write(STDERR_FILENO, "execvp: ", 8);
110 (void)write(STDERR_FILENO, p, lp);
111 (void)write(STDERR_FILENO, ": path too long\n", 16);
112 continue;
113 }
114 memcpy(buf, p, lp);
115 buf[lp] = '/';
116 memcpy(buf + lp + 1, name, ln);
117 buf[lp + ln + 1] = '\0';
118
119 retry: (void)execve(bp, argv, envp);
120 switch (errno) {
121 case EACCES:
122 eacces = 1;
123 break;
124 case ENOTDIR:
125 case ENOENT:
126 break;
127 case ENOEXEC:
128 for (cnt = 0; argv[cnt] != NULL; ++cnt)
129 continue;
130 /*
131 * we can't use malloc here because, if we are doing
132 * vfork+exec, it leaks memory in the parent.
133 */
134 if ((memp = alloca((cnt + 2) * sizeof(*memp))) == NULL)
135 goto done;
136 memp[0] = _PATH_BSHELL;
137 memp[1] = bp;
138 (void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp));
139 (void)execve(_PATH_BSHELL, __UNCONST(memp), envp);
140 goto done;
141 case ETXTBSY:
142 if (etxtbsy < 3)
143 (void)sleep(++etxtbsy);
144 goto retry;
145 default:
146 goto done;
147 }
148 } while (*path++ == ':'); /* Otherwise, *path was NUL */
149 if (eacces)
150 errno = EACCES;
151 else if (!errno)
152 errno = ENOENT;
153 done:
154 return (-1);
155 }
156
157 int
execvp(const char * name,char * const * argv)158 execvp(const char *name, char * const *argv)
159 {
160 return execvpe(name, argv, environ);
161 }
162