| 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 */ |