1 /* $NetBSD: execvp.c,v 1.2 1997/04/24 18:55:51 kleink 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 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 static char rcsid[] = "$NetBSD: execvp.c,v 1.2 1997/04/24 18:55:51 kleink Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <errno.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <limits.h> 49 #include <unistd.h> 50 #include <paths.h> 51 52 extern char **environ; 53 54 int 55 execvp(name, argv) 56 const char *name; 57 char * const *argv; 58 { 59 static int memsize; 60 static char **memp; 61 register int cnt, lp, ln; 62 register char *p; 63 int eacces = 0, etxtbsy = 0; 64 char *bp, *cur, *path, buf[PATH_MAX]; 65 66 /* "" is not a valid filename; check this before traversing PATH. */ 67 if (name[0] == '\0') { 68 errno = ENOENT; 69 goto done; 70 } 71 /* If it's an absolute or relative path name, it's easy. */ 72 if (strchr(name, '/')) { 73 bp = (char *)name; 74 cur = path = NULL; 75 goto retry; 76 } 77 bp = buf; 78 79 /* Get the path we're searching. */ 80 if (!(path = getenv("PATH"))) 81 path = _PATH_DEFPATH; 82 cur = path = strdup(path); 83 84 while (p = strsep(&cur, ":")) { 85 /* 86 * It's a SHELL path -- double, leading and trailing colons 87 * mean the current directory. 88 */ 89 if (!*p) { 90 p = "."; 91 lp = 1; 92 } else 93 lp = strlen(p); 94 ln = strlen(name); 95 96 /* 97 * If the path is too long complain. This is a possible 98 * security issue; given a way to make the path too long 99 * the user may execute the wrong program. 100 */ 101 if (lp + ln + 2 > sizeof(buf)) { 102 (void)write(STDERR_FILENO, "execvp: ", 8); 103 (void)write(STDERR_FILENO, p, lp); 104 (void)write(STDERR_FILENO, ": path too long\n", 16); 105 continue; 106 } 107 bcopy(p, buf, lp); 108 buf[lp] = '/'; 109 bcopy(name, buf + lp + 1, ln); 110 buf[lp + ln + 1] = '\0'; 111 112 retry: (void)execve(bp, argv, environ); 113 switch(errno) { 114 case EACCES: 115 eacces = 1; 116 break; 117 case ENOENT: 118 break; 119 case ENOEXEC: 120 for (cnt = 0; argv[cnt]; ++cnt); 121 if ((cnt + 2) * sizeof(char *) > memsize) { 122 memsize = (cnt + 2) * sizeof(char *); 123 if ((memp = realloc(memp, memsize)) == NULL) { 124 memsize = 0; 125 goto done; 126 } 127 } 128 memp[0] = "sh"; 129 memp[1] = bp; 130 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 131 (void)execve(_PATH_BSHELL, memp, environ); 132 goto done; 133 case ETXTBSY: 134 if (etxtbsy < 3) 135 (void)sleep(++etxtbsy); 136 goto retry; 137 default: 138 goto done; 139 } 140 } 141 if (eacces) 142 errno = EACCES; 143 else if (!errno) 144 errno = ENOENT; 145 done: if (path) 146 free(path); 147 return (-1); 148 } 149