1 /* $NetBSD: execvp.c,v 1.31 2014/09/26 19:28:03 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: execvp.c,v 1.31 2014/09/26 19:28:03 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <assert.h> 43 #include <errno.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <limits.h> 48 #include <unistd.h> 49 #include <paths.h> 50 #include "reentrant.h" 51 52 #ifdef __weak_alias 53 __weak_alias(execvp,_execvp) 54 __weak_alias(execvpe,_execvpe) 55 #endif 56 57 int 58 execvpe(const char *name, char * const *argv, char * const * envp) 59 { 60 const char **memp; 61 int cnt; 62 size_t lp, ln; 63 int eacces = 0; 64 unsigned int etxtbsy = 0; 65 char buf[PATH_MAX]; 66 const char *bp, *path, *p; 67 68 _DIAGASSERT(name != NULL); 69 70 /* "" is not a valid filename; check this before traversing PATH. */ 71 if (name[0] == '\0') { 72 errno = ENOENT; 73 goto done; 74 } 75 ln = strlen(name); 76 /* If it's an absolute or relative path name, it's easy. */ 77 if (strchr(name, '/')) { 78 bp = name; 79 path = ""; 80 goto retry; 81 } 82 bp = buf; 83 84 /* Get the path we're searching. */ 85 if (!(path = getenv("PATH"))) 86 path = _PATH_DEFPATH; 87 88 do { 89 /* Find the end of this path element. */ 90 for (p = path; *path != 0 && *path != ':'; path++) 91 continue; 92 /* 93 * It's a SHELL path -- double, leading and trailing colons 94 * mean the current directory. 95 */ 96 if (p == path) { 97 p = "."; 98 lp = 1; 99 } else 100 lp = path - p; 101 102 /* 103 * If the path is too long complain. This is a possible 104 * security issue; given a way to make the path too long 105 * the user may execute the wrong program. 106 */ 107 if (lp + ln + 2 > sizeof(buf)) { 108 (void)write(STDERR_FILENO, "execvp: ", 8); 109 (void)write(STDERR_FILENO, p, lp); 110 (void)write(STDERR_FILENO, ": path too long\n", 16); 111 continue; 112 } 113 memcpy(buf, p, lp); 114 buf[lp] = '/'; 115 memcpy(buf + lp + 1, name, ln); 116 buf[lp + ln + 1] = '\0'; 117 118 retry: (void)execve(bp, argv, envp); 119 switch (errno) { 120 case EACCES: 121 eacces = 1; 122 break; 123 case ENOTDIR: 124 case ENOENT: 125 break; 126 case ENOEXEC: 127 for (cnt = 0; argv[cnt] != NULL; ++cnt) 128 continue; 129 /* 130 * we can't use malloc here because, if we are doing 131 * vfork+exec, it leaks memory in the parent. 132 */ 133 if ((memp = alloca((cnt + 2) * sizeof(*memp))) == NULL) 134 goto done; 135 memp[0] = _PATH_BSHELL; 136 memp[1] = bp; 137 (void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp)); 138 (void)execve(_PATH_BSHELL, __UNCONST(memp), envp); 139 goto done; 140 case ETXTBSY: 141 if (etxtbsy < 3) 142 (void)sleep(++etxtbsy); 143 goto retry; 144 default: 145 goto done; 146 } 147 } while (*path++ == ':'); /* Otherwise, *path was NUL */ 148 if (eacces) 149 errno = EACCES; 150 else if (!errno) 151 errno = ENOENT; 152 done: 153 return (-1); 154 } 155 156 extern char **environ; 157 158 int 159 execvp(const char *name, char * const *argv) 160 { 161 return execvpe(name, argv, environ); 162 } 163