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cf0bd2f7 | 1 | /* Computing deadlines for timeouts. |
2b778ceb | 2 | Copyright (C) 2017-2021 Free Software Foundation, Inc. |
cf0bd2f7 FW |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
cf0bd2f7 FW |
18 | |
19 | #include <net-internal.h> | |
20 | ||
21 | #include <assert.h> | |
22 | #include <limits.h> | |
23 | #include <stdio.h> | |
24 | #include <stdint.h> | |
25 | #include <time.h> | |
26 | ||
9da93bd7 | 27 | struct deadline_current_time |
cf0bd2f7 FW |
28 | __deadline_current_time (void) |
29 | { | |
30 | struct deadline_current_time result; | |
e008836c LM |
31 | if (__clock_gettime64 (CLOCK_MONOTONIC, &result.current) != 0) |
32 | __clock_gettime64 (CLOCK_REALTIME, &result.current); | |
cf0bd2f7 FW |
33 | assert (result.current.tv_sec >= 0); |
34 | return result; | |
35 | } | |
36 | ||
37 | /* A special deadline value for which __deadline_is_infinite is | |
38 | true. */ | |
39 | static inline struct deadline | |
40 | infinite_deadline (void) | |
41 | { | |
42 | return (struct deadline) { { -1, -1 } }; | |
43 | } | |
44 | ||
9da93bd7 | 45 | struct deadline |
cf0bd2f7 FW |
46 | __deadline_from_timeval (struct deadline_current_time current, |
47 | struct timeval tv) | |
48 | { | |
49 | assert (__is_timeval_valid_timeout (tv)); | |
50 | ||
51 | /* Compute second-based deadline. Perform the addition in | |
52 | uintmax_t, which is unsigned, to simply overflow detection. */ | |
53 | uintmax_t sec = current.current.tv_sec; | |
54 | sec += tv.tv_sec; | |
55 | if (sec < (uintmax_t) tv.tv_sec) | |
56 | return infinite_deadline (); | |
57 | ||
58 | /* Compute nanosecond deadline. */ | |
59 | int nsec = current.current.tv_nsec + tv.tv_usec * 1000; | |
60 | if (nsec >= 1000 * 1000 * 1000) | |
61 | { | |
62 | /* Carry nanosecond overflow to seconds. */ | |
63 | nsec -= 1000 * 1000 * 1000; | |
64 | if (sec + 1 < sec) | |
65 | return infinite_deadline (); | |
66 | ++sec; | |
67 | } | |
68 | /* This uses a GCC extension, otherwise these casts for detecting | |
69 | overflow would not be defined. */ | |
70 | if ((time_t) sec < 0 || sec != (uintmax_t) (time_t) sec) | |
71 | return infinite_deadline (); | |
72 | ||
73 | return (struct deadline) { { sec, nsec } }; | |
74 | } | |
75 | ||
9da93bd7 | 76 | int |
cf0bd2f7 FW |
77 | __deadline_to_ms (struct deadline_current_time current, |
78 | struct deadline deadline) | |
79 | { | |
80 | if (__deadline_is_infinite (deadline)) | |
81 | return INT_MAX; | |
82 | ||
83 | if (current.current.tv_sec > deadline.absolute.tv_sec | |
84 | || (current.current.tv_sec == deadline.absolute.tv_sec | |
85 | && current.current.tv_nsec >= deadline.absolute.tv_nsec)) | |
86 | return 0; | |
87 | time_t sec = deadline.absolute.tv_sec - current.current.tv_sec; | |
88 | if (sec >= INT_MAX) | |
89 | /* This value will overflow below. */ | |
90 | return INT_MAX; | |
91 | int nsec = deadline.absolute.tv_nsec - current.current.tv_nsec; | |
92 | if (nsec < 0) | |
93 | { | |
94 | /* Borrow from the seconds field. */ | |
95 | assert (sec > 0); | |
96 | --sec; | |
97 | nsec += 1000 * 1000 * 1000; | |
98 | } | |
99 | ||
100 | /* Prepare for rounding up to milliseconds. */ | |
101 | nsec += 999999; | |
102 | if (nsec > 1000 * 1000 * 1000) | |
103 | { | |
104 | assert (sec < INT_MAX); | |
105 | ++sec; | |
106 | nsec -= 1000 * 1000 * 1000; | |
107 | } | |
108 | ||
109 | unsigned int msec = nsec / (1000 * 1000); | |
110 | if (sec > INT_MAX / 1000) | |
111 | return INT_MAX; | |
112 | msec += sec * 1000; | |
113 | if (msec > INT_MAX) | |
114 | return INT_MAX; | |
115 | return msec; | |
116 | } |