1 /* 2 * $OpenBSD: readlink.c,v 1.24 2007/09/10 07:42:26 sobrado Exp $ 3 * 4 * Copyright (c) 1997 5 * Kenneth Stailey (hereinafter referred to as the author) 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include <limits.h> 31 #include <errno.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 static void usage(void); 38 39 int 40 main(int argc, char *argv[]) 41 { 42 char buf[PATH_MAX]; 43 int n, ch, nflag = 0, fflag = 0; 44 extern int optind; 45 46 while ((ch = getopt(argc, argv, "fn")) != -1) 47 switch (ch) { 48 case 'f': 49 fflag = 1; 50 break; 51 case 'n': 52 nflag = 1; 53 break; 54 default: 55 usage(); 56 } 57 argc -= optind; 58 argv += optind; 59 60 if (argc != 1) 61 usage(); 62 63 n = strlen(argv[0]); 64 if (n > PATH_MAX - 1) { 65 fprintf(stderr, 66 "readlink: filename longer than PATH_MAX-1 (%d)\n", 67 PATH_MAX - 1); 68 exit(1); 69 } 70 71 if (fflag) { 72 if (realpath(argv[0], buf) == NULL) 73 err(1, "%s", argv[0]); 74 } else { 75 if ((n = readlink(argv[0], buf, sizeof buf-1)) < 0) 76 exit(1); 77 buf[n] = '\0'; 78 } 79 80 printf("%s", buf); 81 if (!nflag) 82 putchar('\n'); 83 exit(0); 84 } 85 86 static void 87 usage(void) 88 { 89 (void)fprintf(stderr, "usage: readlink [-fn] file\n"); 90 exit(1); 91 } 92