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 * 26 * $FreeBSD$ 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 /* If called without args, die silently to conform */ 54 if (argc < 2) 55 exit(EXIT_FAILURE); 56 57 while ((opt = getopt(argc, argv, "as")) != -1) { 58 switch (opt) { 59 case 'a': 60 allpaths = 1; 61 break; 62 case 's': 63 silent = 1; 64 break; 65 default: 66 usage(); 67 break; 68 } 69 } 70 71 argv += optind; 72 argc -= optind; 73 74 if ((p = getenv("PATH")) == NULL) 75 exit(EXIT_FAILURE); 76 pathlen = strlen(p) + 1; 77 path = malloc(pathlen); 78 if (path == NULL) 79 err(EXIT_FAILURE, NULL); 80 81 if (argc == 0) 82 status = EXIT_FAILURE; 83 84 while (argc > 0) { 85 memcpy(path, p, pathlen); 86 87 if (strlen(*argv) > FILENAME_MAX || 88 print_matches(path, *argv) == -1) 89 status = EXIT_FAILURE; 90 91 argv++; 92 argc--; 93 } 94 95 exit(status); 96 } 97 98 static void 99 usage(void) 100 { 101 102 errx(EXIT_FAILURE, "usage: which [-as] program ..."); 103 } 104 105 static int 106 is_there(char *candidate) 107 { 108 struct stat fin; 109 110 /* XXX work around access(2) false positives for superuser */ 111 if (access(candidate, X_OK) == 0 && 112 stat(candidate, &fin) == 0 && 113 S_ISREG(fin.st_mode) && 114 (getuid() != 0 || 115 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) { 116 if (!silent) 117 printf("%s\n", candidate); 118 return (1); 119 } 120 return (0); 121 } 122 123 static int 124 print_matches(char *path, char *filename) 125 { 126 char candidate[PATH_MAX]; 127 char *d; 128 int found; 129 130 if (*filename == '/') 131 return (is_there(filename) ? 0 : -1); 132 found = 0; 133 while ((d = strsep(&path, ":")) != NULL) { 134 if (snprintf(candidate, sizeof(candidate), "%s/%s", d, 135 filename) >= sizeof(candidate)) 136 continue; 137 if (is_there(candidate)) { 138 found = 1; 139 if (!allpaths) 140 break; 141 } 142 } 143 return (found ? 0 : -1); 144 } 145 146