1 /* $NetBSD: execvp.c,v 1.20 2001/12/08 00:30:59 enami 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 1.20 2001/12/08 00:30:59 enami 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(const char *name, char * const *argv) 67 { 68 const char **memp; 69 int cnt; 70 size_t lp, ln; 71 int eacces = 0; 72 unsigned int etxtbsy = 0; 73 char buf[PATH_MAX]; 74 const char *bp, *path, *p; 75 76 _DIAGASSERT(name != NULL); 77 78 /* "" is not a valid filename; check this before traversing PATH. */ 79 if (name[0] == '\0') { 80 errno = ENOENT; 81 goto done; 82 } 83 /* If it's an absolute or relative path name, it's easy. */ 84 if (strchr(name, '/')) { 85 bp = name; 86 path = ""; 87 goto retry; 88 } 89 bp = buf; 90 91 /* Get the path we're searching. */ 92 if (!(path = getenv("PATH"))) 93 path = _PATH_DEFPATH; 94 95 ln = strlen(name); 96 do { 97 /* Find the end of this path element. */ 98 for (p = path; *path != 0 && *path != ':'; path++) 99 continue; 100 /* 101 * It's a SHELL path -- double, leading and trailing colons 102 * mean the current directory. 103 */ 104 if (p == path) { 105 p = "."; 106 lp = 1; 107 } else 108 lp = path - p; 109 110 /* 111 * If the path is too long complain. This is a possible 112 * security issue; given a way to make the path too long 113 * the user may execute the wrong program. 114 */ 115 if (lp + ln + 2 > sizeof(buf)) { 116 (void)write(STDERR_FILENO, "execvp: ", 8); 117 (void)write(STDERR_FILENO, p, lp); 118 (void)write(STDERR_FILENO, ": path too long\n", 16); 119 continue; 120 } 121 memcpy(buf, p, lp); 122 buf[lp] = '/'; 123 memcpy(buf + lp + 1, name, ln); 124 buf[lp + ln + 1] = '\0'; 125 126 retry: rwlock_rdlock(&__environ_lock); 127 (void)execve(bp, argv, environ); 128 rwlock_unlock(&__environ_lock); 129 switch (errno) { 130 case EACCES: 131 eacces = 1; 132 break; 133 case ENOENT: 134 break; 135 case ENOEXEC: 136 for (cnt = 0; argv[cnt] != NULL; ++cnt) 137 continue; 138 if ((memp = alloca((cnt + 2) * sizeof(*memp))) == NULL) 139 goto done; 140 memp[0] = _PATH_BSHELL; 141 memp[1] = bp; 142 (void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp)); 143 rwlock_rdlock(&__environ_lock); 144 (void)execve(_PATH_BSHELL, (char * const *)memp, 145 environ); 146 rwlock_unlock(&__environ_lock); 147 goto done; 148 case ETXTBSY: 149 if (etxtbsy < 3) 150 (void)sleep(++etxtbsy); 151 goto retry; 152 default: 153 goto done; 154 } 155 } while (*path++ == ':'); /* Otherwise, *path was NUL */ 156 if (eacces) 157 errno = EACCES; 158 else if (!errno) 159 errno = ENOENT; 160 done: 161 return (-1); 162 } 163