1 /* $NetBSD: execvp.c,v 1.10 1998/11/12 16:09:46 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 1.10 1998/11/12 16:09:46 christos 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 static size_t memsize; 70 static 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 /* "" is not a valid filename; check this before traversing PATH. */ 80 if (name[0] == '\0') { 81 errno = ENOENT; 82 path = NULL; 83 goto done; 84 } 85 /* If it's an absolute or relative path name, it's easy. */ 86 if (strchr(name, '/')) { 87 bp = name; 88 cur = path = NULL; 89 goto retry; 90 } 91 bp = buf; 92 93 /* Get the path we're searching. */ 94 if (!(path = getenv("PATH"))) 95 path = _PATH_DEFPATH; 96 cur = path = strdup(path); 97 98 while ((p = strsep(&cur, ":")) != NULL) { 99 /* 100 * It's a SHELL path -- double, leading and trailing colons 101 * mean the current directory. 102 */ 103 if (!*p) { 104 p = "."; 105 lp = 1; 106 } else 107 lp = strlen(p); 108 ln = strlen(name); 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 memmove(buf, p, lp); 122 buf[lp] = '/'; 123 memmove(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]; ++cnt); 137 if ((cnt + 2) * sizeof(char *) > memsize) { 138 memsize = (cnt + 2) * sizeof(char *); 139 if ((memp = realloc(memp, memsize)) == NULL) { 140 memsize = 0; 141 goto done; 142 } 143 } 144 memp[0] = "sh"; 145 memp[1] = bp; 146 memmove(memp + 2, argv + 1, cnt * sizeof(char *)); 147 rwlock_rdlock(&__environ_lock); 148 (void)execve(_PATH_BSHELL, (char * const *)memp, environ); 149 rwlock_unlock(&__environ_lock); 150 goto done; 151 case ETXTBSY: 152 if (etxtbsy < 3) 153 (void)sleep(++etxtbsy); 154 goto retry; 155 default: 156 goto done; 157 } 158 } 159 if (eacces) 160 errno = EACCES; 161 else if (!errno) 162 errno = ENOENT; 163 done: if (path) 164 free(path); 165 return (-1); 166 } 167