1 /* $NetBSD: execvp.c,v 1.23 2003/03/15 04:41:17 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. 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 1.23 2003/03/15 04:41:17 christos 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 62 int 63 execvp(const char *name, char * const *argv) 64 { 65 const char **memp; 66 int cnt; 67 size_t lp, ln; 68 int eacces = 0; 69 unsigned int etxtbsy = 0; 70 char buf[PATH_MAX]; 71 const char *bp, *path, *p; 72 73 _DIAGASSERT(name != NULL); 74 75 /* "" is not a valid filename; check this before traversing PATH. */ 76 if (name[0] == '\0') { 77 errno = ENOENT; 78 goto done; 79 } 80 /* If it's an absolute or relative path name, it's easy. */ 81 if (strchr(name, '/')) { 82 bp = name; 83 path = ""; 84 goto retry; 85 } 86 bp = buf; 87 88 /* Get the path we're searching. */ 89 if (!(path = getenv("PATH"))) 90 path = _PATH_DEFPATH; 91 92 ln = strlen(name); 93 do { 94 /* Find the end of this path element. */ 95 for (p = path; *path != 0 && *path != ':'; path++) 96 continue; 97 /* 98 * It's a SHELL path -- double, leading and trailing colons 99 * mean the current directory. 100 */ 101 if (p == path) { 102 p = "."; 103 lp = 1; 104 } else 105 lp = path - p; 106 107 /* 108 * If the path is too long complain. This is a possible 109 * security issue; given a way to make the path too long 110 * the user may execute the wrong program. 111 */ 112 if (lp + ln + 2 > sizeof(buf)) { 113 (void)write(STDERR_FILENO, "execvp: ", 8); 114 (void)write(STDERR_FILENO, p, lp); 115 (void)write(STDERR_FILENO, ": path too long\n", 16); 116 continue; 117 } 118 memcpy(buf, p, lp); 119 buf[lp] = '/'; 120 memcpy(buf + lp + 1, name, ln); 121 buf[lp + ln + 1] = '\0'; 122 123 retry: (void)execve(bp, argv, environ); 124 switch (errno) { 125 case EACCES: 126 eacces = 1; 127 break; 128 case ENOTDIR: 129 case ENOENT: 130 break; 131 case ENOEXEC: 132 for (cnt = 0; argv[cnt] != NULL; ++cnt) 133 continue; 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, (char * const *)memp, 140 environ); 141 goto done; 142 case ETXTBSY: 143 if (etxtbsy < 3) 144 (void)sleep(++etxtbsy); 145 goto retry; 146 default: 147 goto done; 148 } 149 } while (*path++ == ':'); /* Otherwise, *path was NUL */ 150 if (eacces) 151 errno = EACCES; 152 else if (!errno) 153 errno = ENOENT; 154 done: 155 return (-1); 156 } 157