1 /* $NetBSD: execvp.c,v 1.16 2000/01/22 22:19:09 mycroft 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 __RCSID("$NetBSD: execvp.c,v 1.16 2000/01/22 22:19:09 mycroft Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <assert.h> 47 #include <errno.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <limits.h> 52 #include <unistd.h> 53 #include <paths.h> 54 #include "reentrant.h" 55 56 #ifdef __weak_alias 57 __weak_alias(execvp,_execvp) 58 #endif 59 60 extern char **environ; 61 #ifdef _REENT 62 extern rwlock_t __environ_lock; 63 #endif 64 65 int 66 execvp(name, argv) 67 const char *name; 68 char * const *argv; 69 { 70 const char **memp; 71 int cnt; 72 size_t lp, ln; 73 char *p; 74 int eacces = 0; 75 unsigned int etxtbsy = 0; 76 char *cur, *path, buf[PATH_MAX]; 77 const char *bp; 78 79 _DIAGASSERT(name != NULL); 80 81 /* "" is not a valid filename; check this before traversing PATH. */ 82 if (name[0] == '\0') { 83 errno = ENOENT; 84 path = NULL; 85 goto done; 86 } 87 /* If it's an absolute or relative path name, it's easy. */ 88 if (strchr(name, '/')) { 89 bp = name; 90 cur = path = NULL; 91 goto retry; 92 } 93 bp = buf; 94 95 /* Get the path we're searching. */ 96 if (!(path = getenv("PATH"))) 97 path = _PATH_DEFPATH; 98 cur = path = strdup(path); 99 100 while ((p = strsep(&cur, ":")) != NULL) { 101 /* 102 * It's a SHELL path -- double, leading and trailing colons 103 * mean the current directory. 104 */ 105 if (!*p) { 106 p = "."; 107 lp = 1; 108 } else 109 lp = strlen(p); 110 ln = strlen(name); 111 112 /* 113 * If the path is too long complain. This is a possible 114 * security issue; given a way to make the path too long 115 * the user may execute the wrong program. 116 */ 117 if (lp + ln + 2 > sizeof(buf)) { 118 (void)write(STDERR_FILENO, "execvp: ", 8); 119 (void)write(STDERR_FILENO, p, lp); 120 (void)write(STDERR_FILENO, ": path too long\n", 16); 121 continue; 122 } 123 memmove(buf, p, lp); 124 buf[lp] = '/'; 125 memmove(buf + lp + 1, name, ln); 126 buf[lp + ln + 1] = '\0'; 127 128 retry: rwlock_rdlock(&__environ_lock); 129 (void)execve(bp, argv, environ); 130 rwlock_unlock(&__environ_lock); 131 switch (errno) { 132 case EACCES: 133 eacces = 1; 134 break; 135 case ENOENT: 136 break; 137 case ENOEXEC: 138 for (cnt = 0; argv[cnt] != NULL; ++cnt); 139 if ((memp = malloc((cnt + 2) * sizeof (*memp))) == NULL) 140 goto done; 141 memp[0] = _PATH_BSHELL; 142 memp[1] = bp; 143 (void)memmove(&memp[2], &argv[1], cnt * sizeof (*memp)); 144 rwlock_rdlock(&__environ_lock); 145 (void)execve(_PATH_BSHELL, (char * const *)memp, environ); 146 rwlock_unlock(&__environ_lock); 147 free(memp); 148 goto done; 149 case ETXTBSY: 150 if (etxtbsy < 3) 151 (void)sleep(++etxtbsy); 152 goto retry; 153 default: 154 goto done; 155 } 156 } 157 if (eacces) 158 errno = EACCES; 159 else if (!errno) 160 errno = ENOENT; 161 done: if (path) 162 free(path); 163 return (-1); 164 } 165