1 /*
2 * Copyright (c) 2013, The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google, Inc. nor the names of its contributors
15 * may be used to endorse or promote products derived from this
16 * software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
25 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
28 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <limits.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <unistd.h>
36
37 static int skip_newline, quiet_errors, canonicalize;
38
usage(char * name)39 static void usage(char* name) {
40 fprintf(stderr, "Usage: %s [OPTION]... FILE\n", name);
41 }
42
readlink_main(int argc,char * argv[])43 int readlink_main(int argc, char* argv[]) {
44 int c;
45 while ((c = getopt(argc, argv, "nfqs")) != -1) {
46 switch (c) {
47 case 'n':
48 skip_newline = 1;
49 break;
50 case 'f':
51 canonicalize = 1;
52 break;
53 case 'q':
54 case 's':
55 quiet_errors = 1;
56 break;
57 case '?':
58 default:
59 usage(argv[0]);
60 return EXIT_FAILURE;
61 }
62 }
63 int index = optind;
64 if (argc - index != 1) {
65 usage(argv[0]);
66 return EXIT_FAILURE;
67 }
68
69 char name[PATH_MAX+1];
70 if (canonicalize) {
71 if(!realpath(argv[optind], name)) {
72 if (!quiet_errors) {
73 perror("readlink");
74 }
75 return EXIT_FAILURE;
76 }
77 } else {
78 ssize_t len = readlink(argv[1], name, PATH_MAX);
79
80 if (len < 0) {
81 if (!quiet_errors) {
82 perror("readlink");
83 }
84 return EXIT_FAILURE;
85 }
86 name[len] = '\0';
87 }
88
89 fputs(name, stdout);
90 if (!skip_newline) {
91 fputs("\n", stdout);
92 }
93
94 return EXIT_SUCCESS;
95 }
96