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