1 /* $NetBSD: execvp.c,v 1.13 1999/09/16 11:36:19 lukem 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 1.13 1999/09/16 11:36:19 lukem Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <errno.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <limits.h> 51 #include <unistd.h> 52 #include <paths.h> 53 #include "reentrant.h" 54 55 #ifdef __weak_alias 56 __weak_alias(execvp,_execvp); 57 #endif 58 59 extern char **environ; 60 #ifdef _REENT 61 extern rwlock_t __environ_lock; 62 #endif 63 64 int 65 execvp(name, argv) 66 const char *name; 67 char * const *argv; 68 { 69 const char **memp; 70 int cnt; 71 size_t lp, ln; 72 char *p; 73 int eacces = 0; 74 unsigned int etxtbsy = 0; 75 char *cur, *path, buf[PATH_MAX]; 76 const char *bp; 77 78 /* "" is not a valid filename; check this before traversing PATH. */ 79 if (name[0] == '\0') { 80 errno = ENOENT; 81 path = NULL; 82 goto done; 83 } 84 /* If it's an absolute or relative path name, it's easy. */ 85 if (strchr(name, '/')) { 86 bp = name; 87 cur = path = NULL; 88 goto retry; 89 } 90 bp = buf; 91 92 /* Get the path we're searching. */ 93 if (!(path = getenv("PATH"))) 94 path = _PATH_DEFPATH; 95 cur = path = strdup(path); 96 97 while ((p = strsep(&cur, ":")) != NULL) { 98 /* 99 * It's a SHELL path -- double, leading and trailing colons 100 * mean the current directory. 101 */ 102 if (!*p) { 103 p = "."; 104 lp = 1; 105 } else 106 lp = strlen(p); 107 ln = strlen(name); 108 109 /* 110 * If the path is too long complain. This is a possible 111 * security issue; given a way to make the path too long 112 * the user may execute the wrong program. 113 */ 114 if (lp + ln + 2 > sizeof(buf)) { 115 (void)write(STDERR_FILENO, "execvp: ", 8); 116 (void)write(STDERR_FILENO, p, lp); 117 (void)write(STDERR_FILENO, ": path too long\n", 16); 118 continue; 119 } 120 memmove(buf, p, lp); 121 buf[lp] = '/'; 122 memmove(buf + lp + 1, name, ln); 123 buf[lp + ln + 1] = '\0'; 124 125 retry: rwlock_rdlock(&__environ_lock); 126 (void)execve(bp, argv, environ); 127 rwlock_unlock(&__environ_lock); 128 switch (errno) { 129 case EACCES: 130 eacces = 1; 131 break; 132 case ENOENT: 133 break; 134 case ENOEXEC: 135 for (cnt = 0; argv[cnt] != NULL; ++cnt); 136 if ((memp = malloc((cnt + 2) * sizeof (*memp))) == NULL) 137 goto done; 138 memp[0] = _PATH_BSHELL; 139 memp[1] = bp; 140 (void)memmove(&memp[2], &argv[1], cnt * sizeof (*memp)); 141 rwlock_rdlock(&__environ_lock); 142 (void)execve(_PATH_BSHELL, (char * const *)memp, environ); 143 rwlock_unlock(&__environ_lock); 144 free(memp); 145 goto done; 146 case ETXTBSY: 147 if (etxtbsy < 3) 148 (void)sleep(++etxtbsy); 149 goto retry; 150 default: 151 goto done; 152 } 153 } 154 if (eacces) 155 errno = EACCES; 156 else if (!errno) 157 errno = ENOENT; 158 done: if (path) 159 free(path); 160 return (-1); 161 } 162