1 /* $NetBSD: execvp.c,v 1.3 1997/07/13 18:57:04 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 1.3 1997/07/13 18:57:04 christos Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <limits.h> 50 #include <unistd.h> 51 #include <paths.h> 52 53 extern char **environ; 54 55 int 56 execvp(name, argv) 57 const char *name; 58 char * const *argv; 59 { 60 static int memsize; 61 static char **memp; 62 register int cnt, lp, ln; 63 register char *p; 64 int eacces = 0, etxtbsy = 0; 65 char *bp, *cur, *path, buf[PATH_MAX]; 66 67 /* "" is not a valid filename; check this before traversing PATH. */ 68 if (name[0] == '\0') { 69 errno = ENOENT; 70 path = NULL; 71 goto done; 72 } 73 /* If it's an absolute or relative path name, it's easy. */ 74 if (strchr(name, '/')) { 75 bp = (char *)name; 76 cur = path = NULL; 77 goto retry; 78 } 79 bp = buf; 80 81 /* Get the path we're searching. */ 82 if (!(path = getenv("PATH"))) 83 path = _PATH_DEFPATH; 84 cur = path = strdup(path); 85 86 while ((p = strsep(&cur, ":")) != NULL) { 87 /* 88 * It's a SHELL path -- double, leading and trailing colons 89 * mean the current directory. 90 */ 91 if (!*p) { 92 p = "."; 93 lp = 1; 94 } else 95 lp = strlen(p); 96 ln = strlen(name); 97 98 /* 99 * If the path is too long complain. This is a possible 100 * security issue; given a way to make the path too long 101 * the user may execute the wrong program. 102 */ 103 if (lp + ln + 2 > sizeof(buf)) { 104 (void)write(STDERR_FILENO, "execvp: ", 8); 105 (void)write(STDERR_FILENO, p, lp); 106 (void)write(STDERR_FILENO, ": path too long\n", 16); 107 continue; 108 } 109 bcopy(p, buf, lp); 110 buf[lp] = '/'; 111 bcopy(name, buf + lp + 1, ln); 112 buf[lp + ln + 1] = '\0'; 113 114 retry: (void)execve(bp, argv, environ); 115 switch(errno) { 116 case EACCES: 117 eacces = 1; 118 break; 119 case ENOENT: 120 break; 121 case ENOEXEC: 122 for (cnt = 0; argv[cnt]; ++cnt); 123 if ((cnt + 2) * sizeof(char *) > memsize) { 124 memsize = (cnt + 2) * sizeof(char *); 125 if ((memp = realloc(memp, memsize)) == NULL) { 126 memsize = 0; 127 goto done; 128 } 129 } 130 memp[0] = "sh"; 131 memp[1] = bp; 132 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 133 (void)execve(_PATH_BSHELL, memp, environ); 134 goto done; 135 case ETXTBSY: 136 if (etxtbsy < 3) 137 (void)sleep(++etxtbsy); 138 goto retry; 139 default: 140 goto done; 141 } 142 } 143 if (eacces) 144 errno = EACCES; 145 else if (!errno) 146 errno = ENOENT; 147 done: if (path) 148 free(path); 149 return (-1); 150 } 151