xref: /openbsd/usr.bin/dig/lib/dns/ttl.c (revision f6aab3d8)
1 /*
2  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
9  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
10  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
11  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
12  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
13  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
14  * PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /* $Id: ttl.c,v 1.6 2020/09/14 08:40:43 florian Exp $ */
18 
19 /*! \file */
20 
21 #include <ctype.h>
22 #include <stdio.h>
23 #include <string.h>
24 
25 #include <isc/buffer.h>
26 #include <isc/region.h>
27 #include <isc/util.h>
28 
29 #include <dns/ttl.h>
30 
31 #define RETERR(x) do { \
32 	isc_result_t _r = (x); \
33 	if (_r != ISC_R_SUCCESS) \
34 		return (_r); \
35 	} while (0)
36 
37 /*
38  * Helper for dns_ttl_totext().
39  */
40 static isc_result_t
41 ttlfmt(unsigned int t, const char *s, int verbose,
42        int space, isc_buffer_t *target)
43 {
44 	char tmp[60];
45 	unsigned int len;
46 	isc_region_t region;
47 
48 	if (verbose)
49 		len = snprintf(tmp, sizeof(tmp), "%s%u %s%s",
50 			       space ? " " : "",
51 			       t, s,
52 			       t == 1 ? "" : "s");
53 	else
54 		len = snprintf(tmp, sizeof(tmp), "%u%c", t, s[0]);
55 
56 	INSIST(len + 1 <= sizeof(tmp));
57 	isc_buffer_availableregion(target, &region);
58 	if (len > region.length)
59 		return (ISC_R_NOSPACE);
60 	memmove(region.base, tmp, len);
61 	isc_buffer_add(target, len);
62 
63 	return (ISC_R_SUCCESS);
64 }
65 
66 /*
67  * Derived from bind8 ns_format_ttl().
68  */
69 isc_result_t
70 dns_ttl_totext(uint32_t src, int verbose, isc_buffer_t *target) {
71 	unsigned secs, mins, hours, days, weeks, x;
72 
73 	secs = src % 60;   src /= 60;
74 	mins = src % 60;   src /= 60;
75 	hours = src % 24;  src /= 24;
76 	days = src % 7;    src /= 7;
77 	weeks = src;       src = 0;
78 	POST(src);
79 
80 	x = 0;
81 	if (weeks != 0) {
82 		RETERR(ttlfmt(weeks, "week", verbose, (x > 0), target));
83 		x++;
84 	}
85 	if (days != 0) {
86 		RETERR(ttlfmt(days, "day", verbose, (x > 0), target));
87 		x++;
88 	}
89 	if (hours != 0) {
90 		RETERR(ttlfmt(hours, "hour", verbose, (x > 0), target));
91 		x++;
92 	}
93 	if (mins != 0) {
94 		RETERR(ttlfmt(mins, "minute", verbose, (x > 0), target));
95 		x++;
96 	}
97 	if (secs != 0 ||
98 	    (weeks == 0 && days == 0 && hours == 0 && mins == 0)) {
99 		RETERR(ttlfmt(secs, "second", verbose, (x > 0), target));
100 		x++;
101 	}
102 	INSIST (x > 0);
103 	/*
104 	 * If only a single unit letter is printed, print it
105 	 * in upper case. (Why?  Because BIND 8 does that.
106 	 * Presumably it has a reason.)
107 	 */
108 	if (x == 1 && !verbose) {
109 		isc_region_t region;
110 		/*
111 		 * The unit letter is the last character in the
112 		 * used region of the buffer.
113 		 *
114 		 * toupper() does not need its argument to be masked of cast
115 		 * here because region.base is type unsigned char *.
116 		 */
117 		isc_buffer_usedregion(target, &region);
118 		region.base[region.length - 1] =
119 			toupper(region.base[region.length - 1]);
120 	}
121 	return (ISC_R_SUCCESS);
122 }
123