1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2000 Dan Papasian. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/stat.h> 35 #include <err.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 static void usage(void); 42 static int print_matches(char *, char *); 43 44 static int silent; 45 static int allpaths; 46 47 int 48 main(int argc, char **argv) 49 { 50 char *p, *path; 51 ssize_t pathlen; 52 int opt, status; 53 54 status = EXIT_SUCCESS; 55 56 while ((opt = getopt(argc, argv, "as")) != -1) { 57 switch (opt) { 58 case 'a': 59 allpaths = 1; 60 break; 61 case 's': 62 silent = 1; 63 break; 64 default: 65 usage(); 66 break; 67 } 68 } 69 70 argv += optind; 71 argc -= optind; 72 73 if (argc == 0) 74 usage(); 75 76 if ((p = getenv("PATH")) == NULL) 77 exit(EXIT_FAILURE); 78 pathlen = strlen(p) + 1; 79 path = malloc(pathlen); 80 if (path == NULL) 81 err(EXIT_FAILURE, NULL); 82 83 while (argc > 0) { 84 memcpy(path, p, pathlen); 85 86 if (strlen(*argv) >= FILENAME_MAX || 87 print_matches(path, *argv) == -1) 88 status = EXIT_FAILURE; 89 90 argv++; 91 argc--; 92 } 93 94 exit(status); 95 } 96 97 static void 98 usage(void) 99 { 100 101 (void)fprintf(stderr, "usage: which [-as] program ...\n"); 102 exit(EXIT_FAILURE); 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 const char *d; 128 int found; 129 130 if (strchr(filename, '/') != NULL) 131 return (is_there(filename) ? 0 : -1); 132 found = 0; 133 while ((d = strsep(&path, ":")) != NULL) { 134 if (*d == '\0') 135 d = "."; 136 if (snprintf(candidate, sizeof(candidate), "%s/%s", d, 137 filename) >= (int)sizeof(candidate)) 138 continue; 139 if (is_there(candidate)) { 140 found = 1; 141 if (!allpaths) 142 break; 143 } 144 } 145 return (found ? 0 : -1); 146 } 147 148