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 30 #include <sys/param.h> 31 #include <sys/stat.h> 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 static int silent; 42 static 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, NULL); 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 98 (void)fprintf(stderr, "usage: which [-as] program ...\n"); 99 exit(EXIT_FAILURE); 100 } 101 102 static int 103 is_there(char *candidate) 104 { 105 struct stat fin; 106 107 /* XXX work around access(2) false positives for superuser */ 108 if (access(candidate, X_OK) == 0 && 109 stat(candidate, &fin) == 0 && 110 S_ISREG(fin.st_mode) && 111 (getuid() != 0 || 112 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) { 113 if (!silent) 114 printf("%s\n", candidate); 115 return (1); 116 } 117 return (0); 118 } 119 120 static int 121 print_matches(char *path, char *filename) 122 { 123 char candidate[PATH_MAX]; 124 const char *d; 125 int found; 126 127 if (strchr(filename, '/') != NULL) 128 return (is_there(filename) ? 0 : -1); 129 found = 0; 130 while ((d = strsep(&path, ":")) != NULL) { 131 if (*d == '\0') 132 d = "."; 133 if (snprintf(candidate, sizeof(candidate), "%s/%s", d, 134 filename) >= (int)sizeof(candidate)) 135 continue; 136 if (is_there(candidate)) { 137 found = 1; 138 if (!allpaths) 139 break; 140 } 141 } 142 return (found ? 0 : -1); 143 } 144 145