1/* $NetBSD: execvp.c,v 1.32 2024/01/20 14:52:47 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 35static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93"; 36#else 37__RCSID("$NetBSD: execvp.c,v 1.32 2024/01/20 14:52:47 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#include "extern.h" 52 53#ifdef __weak_alias 54__weak_alias(execvp,_execvp) 55__weak_alias(execvpe,_execvpe) 56#endif 57 58int 59execvpe(const char *name, char * const *argv, char * const * envp) 60{ 61 const char **memp; 62 int cnt; 63 size_t lp, ln; 64 int eacces = 0; 65 unsigned int etxtbsy = 0; 66 char buf[PATH_MAX]; 67 const char *bp, *path, *p; 68 69 _DIAGASSERT(name != NULL); 70 71 /* "" is not a valid filename; check this before traversing PATH. */ 72 if (name[0] == '\0') { 73 errno = ENOENT; 74 goto done; 75 } 76 ln = strlen(name); 77 /* If it's an absolute or relative path name, it's easy. */ 78 if (strchr(name, '/')) { 79 bp = name; 80 path = ""; 81 goto retry; 82 } 83 bp = buf; 84 85 /* Get the path we're searching. */ 86 if (!(path = getenv("PATH"))) 87 path = _PATH_DEFPATH; 88 89 do { 90 /* Find the end of this path element. */ 91 for (p = path; *path != 0 && *path != ':'; path++) 92 continue; 93 /* 94 * It's a SHELL path -- double, leading and trailing colons 95 * mean the current directory. 96 */ 97 if (p == path) { 98 p = "."; 99 lp = 1; 100 } else 101 lp = path - p; 102 103 /* 104 * If the path is too long complain. This is a possible 105 * security issue; given a way to make the path too long 106 * the user may execute the wrong program. 107 */ 108 if (lp + ln + 2 > sizeof(buf)) { 109 (void)write(STDERR_FILENO, "execvp: ", 8); 110 (void)write(STDERR_FILENO, p, lp); 111 (void)write(STDERR_FILENO, ": path too long\n", 16); 112 continue; 113 } 114 memcpy(buf, p, lp); 115 buf[lp] = '/'; 116 memcpy(buf + lp + 1, name, ln); 117 buf[lp + ln + 1] = '\0'; 118 119retry: (void)execve(bp, argv, envp); 120 switch (errno) { 121 case EACCES: 122 eacces = 1; 123 break; 124 case ENOTDIR: 125 case ENOENT: 126 break; 127 case ENOEXEC: 128 for (cnt = 0; argv[cnt] != NULL; ++cnt) 129 continue; 130 /* 131 * we can't use malloc here because, if we are doing 132 * vfork+exec, it leaks memory in the parent. 133 */ 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, __UNCONST(memp), envp); 140 goto done; 141 case ETXTBSY: 142 if (etxtbsy < 3) 143 (void)sleep(++etxtbsy); 144 goto retry; 145 default: 146 goto done; 147 } 148 } while (*path++ == ':'); /* Otherwise, *path was NUL */ 149 if (eacces) 150 errno = EACCES; 151 else if (!errno) 152 errno = ENOENT; 153done: 154 return (-1); 155} 156 157int 158execvp(const char *name, char * const *argv) 159{ 160 return execvpe(name, argv, environ); 161} 162