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1 | #ifndef _BABELTRACE_UTC_H |
2 | #define _BABELTRACE_UTC_H | |
3 | ||
4 | /* | |
5 | * Copyright (C) 2011-2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
8 | * of this software and associated documentation files (the "Software"), to deal | |
9 | * in the Software without restriction, including without limitation the rights | |
10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
11 | * copies of the Software, and to permit persons to whom the Software is | |
12 | * furnished to do so, subject to the following conditions: | |
13 | * | |
14 | * The above copyright notice and this permission notice shall be included in | |
15 | * all copies or substantial portions of the Software. | |
16 | * | |
17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
23 | * SOFTWARE. | |
24 | */ | |
25 | ||
26 | #include <time.h> | |
27 | ||
28 | /* If set, use GNU or BSD timegm(3) */ | |
29 | #if defined(_BSD_SOURCE) || defined(_SVID_SOURCE) | |
30 | ||
31 | static inline | |
32 | time_t babeltrace_timegm(struct tm *tm) | |
33 | { | |
34 | return timegm(tm); | |
35 | } | |
36 | ||
37 | #else | |
38 | ||
39 | #include <string.h> | |
40 | #include <stdlib.h> | |
41 | ||
42 | /* | |
43 | * Note: Below implementation of timegm() is not thread safe | |
44 | * as it changes the environment | |
45 | * variable TZ. It is OK as long as it is kept in self-contained program, | |
46 | * but should not be used within thread-safe library code. | |
47 | */ | |
48 | ||
49 | static inline | |
50 | time_t babeltrace_timegm(struct tm *tm) | |
51 | { | |
52 | time_t ret; | |
53 | char *tz; | |
54 | ||
55 | tz = getenv("TZ"); | |
56 | /* | |
57 | * Make a temporary copy, as the environment variable will be | |
58 | * modified. | |
59 | */ | |
60 | if (tz) { | |
61 | tz = strdup(tz); | |
62 | if (!tz) { | |
63 | /* | |
64 | * Memory allocation error. | |
65 | */ | |
66 | return (time_t) -1; | |
67 | } | |
68 | } | |
69 | ||
70 | /* Temporarily setting TZ to 1 for UTC */ | |
71 | setenv("TZ", "", 1); | |
72 | tzset(); | |
73 | ret = mktime(tm); | |
74 | if (tz) { | |
75 | setenv("TZ", tz, 1); | |
76 | free(tz); | |
77 | } else { | |
78 | unsetenv("TZ"); | |
79 | } | |
80 | tzset(); | |
81 | return ret; | |
82 | } | |
83 | ||
84 | #endif | |
85 | ||
86 | #endif /* _BABELTRACE_UTC_H */ |