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 27 #include <sys/cdefs.h> 28 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/stat.h> 32 #include <sys/param.h> 33 34 #include <err.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <unistd.h> 39 40 static void usage(void); 41 static int print_matches(char *, char *); 42 43 static int silent; 44 static int allpaths; 45 46 int 47 main(int argc, char **argv) 48 { 49 char *p, *path; 50 ssize_t pathlen; 51 int opt, status; 52 53 status = EXIT_SUCCESS; 54 55 while ((opt = getopt(argc, argv, "as")) != -1) { 56 switch (opt) { 57 case 'a': 58 allpaths = 1; 59 break; 60 case 's': 61 silent = 1; 62 break; 63 default: 64 usage(); 65 break; 66 } 67 } 68 69 argv += optind; 70 argc -= optind; 71 72 if (argc == 0) 73 usage(); 74 75 if ((p = getenv("PATH")) == NULL) 76 exit(EXIT_FAILURE); 77 pathlen = strlen(p) + 1; 78 path = malloc(pathlen); 79 if (path == NULL) 80 err(EXIT_FAILURE, NULL); 81 82 while (argc > 0) { 83 memcpy(path, p, pathlen); 84 85 if (strlen(*argv) >= FILENAME_MAX || 86 print_matches(path, *argv) == -1) 87 status = EXIT_FAILURE; 88 89 argv++; 90 argc--; 91 } 92 93 exit(status); 94 } 95 96 static void 97 usage(void) 98 { 99 100 (void)fprintf(stderr, "usage: which [-as] program ...\n"); 101 exit(EXIT_FAILURE); 102 } 103 104 static int 105 is_there(char *candidate) 106 { 107 struct stat fin; 108 109 /* XXX work around access(2) false positives for superuser */ 110 if (access(candidate, X_OK) == 0 && 111 stat(candidate, &fin) == 0 && 112 S_ISREG(fin.st_mode) && 113 (getuid() != 0 || 114 (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) { 115 if (!silent) 116 printf("%s\n", candidate); 117 return (1); 118 } 119 return (0); 120 } 121 122 static int 123 print_matches(char *path, char *filename) 124 { 125 char candidate[PATH_MAX]; 126 const char *d; 127 int found; 128 129 if (strchr(filename, '/') != NULL) 130 return (is_there(filename) ? 0 : -1); 131 found = 0; 132 while ((d = strsep(&path, ":")) != NULL) { 133 if (*d == '\0') 134 d = "."; 135 if (snprintf(candidate, sizeof(candidate), "%s/%s", d, 136 filename) >= (int)sizeof(candidate)) 137 continue; 138 if (is_there(candidate)) { 139 found = 1; 140 if (!allpaths) 141 break; 142 } 143 } 144 return (found ? 0 : -1); 145 } 146 147