1 /** 2 * Copyright (c) 2000 Dan Papasian. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. The name of the author may not be used to endorse or promote products 13 * derived from this software without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * $FreeBSD: src/usr.bin/which/which.c,v 1.5 2002/06/30 06:02:39 tjr Exp $"); 26 * $DragonFly: src/usr.bin/which/which.c,v 1.3 2005/08/30 22:42:15 liamfoy Exp $ 27 */ 28 29 #include <sys/stat.h> 30 #include <sys/param.h> 31 32 #include <err.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <string.h> 36 #include <unistd.h> 37 38 static void usage(void); 39 static int print_matches(char *, char *); 40 41 int silent; 42 int allpaths; 43 44 int 45 main(int argc, char **argv) 46 { 47 char *p, *path; 48 ssize_t pathlen; 49 int opt, status; 50 51 status = EXIT_SUCCESS; 52 53 while ((opt = getopt(argc, argv, "as")) != -1) { 54 switch (opt) { 55 case 'a': 56 allpaths = 1; 57 break; 58 case 's': 59 silent = 1; 60 break; 61 default: 62 usage(); 63 break; 64 } 65 } 66 67 argv += optind; 68 argc -= optind; 69 70 if (argc == 0) 71 usage(); 72 73 if ((p = getenv("PATH")) == NULL) 74 exit(EXIT_FAILURE); 75 pathlen = strlen(p) + 1; 76 path = malloc(pathlen); 77 if (path == NULL) 78 err(EXIT_FAILURE, "malloc failed"); 79 80 while (argc > 0) { 81 memcpy(path, p, pathlen); 82 83 if (strlen(*argv) >= FILENAME_MAX || 84 print_matches(path, *argv) == -1) 85 status = EXIT_FAILURE; 86 87 argv++; 88 argc--; 89 } 90 91 exit(status); 92 } 93 94 static void 95 usage(void) 96 { 97 fprintf(stderr, "usage: which [-as] program ...\n"); 98 exit(EXIT_FAILURE); 99 } 100 101 static int 102 is_there(const char *candidate) 103 { 104 struct stat fin; 105 106 /* XXX work around access(2) false positives for superuser */ 107 if (access(candidate, X_OK) == 0 && 108 stat(candidate, &fin) == 0 && 109 S_ISREG(fin.st_mode) && 110 (getuid() != 0 || 111 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) { 112 if (!silent) 113 printf("%s\n", candidate); 114 return (1); 115 } 116 return (0); 117 } 118 119 static int 120 print_matches(char *path, char *filename) 121 { 122 char candidate[PATH_MAX]; 123 const char *d; 124 int found; 125 126 if (strchr(filename, '/') != NULL) 127 return (is_there(filename) ? 0 : -1); 128 found = 0; 129 while ((d = strsep(&path, ":")) != NULL) { 130 if (*d == '\0') 131 d = "."; 132 if (snprintf(candidate, sizeof(candidate), "%s/%s", d, 133 filename) >= (int)sizeof(candidate)) 134 continue; 135 if (is_there(candidate)) { 136 found = 1; 137 if (!allpaths) 138 break; 139 } 140 } 141 return (found ? 0 : -1); 142 } 143 144