xref: /linux/include/linux/time64.h (revision 46dae32f)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_TIME64_H
3 #define _LINUX_TIME64_H
4 
5 #include <linux/math64.h>
6 #include <vdso/time64.h>
7 
8 typedef __s64 time64_t;
9 typedef __u64 timeu64_t;
10 
11 #include <uapi/linux/time.h>
12 
13 struct timespec64 {
14 	time64_t	tv_sec;			/* seconds */
15 	long		tv_nsec;		/* nanoseconds */
16 };
17 
18 struct itimerspec64 {
19 	struct timespec64 it_interval;
20 	struct timespec64 it_value;
21 };
22 
23 /* Parameters used to convert the timespec values: */
24 #define PSEC_PER_NSEC			1000L
25 
26 /* Located here for timespec[64]_valid_strict */
27 #define TIME64_MAX			((s64)~((u64)1 << 63))
28 #define TIME64_MIN			(-TIME64_MAX - 1)
29 
30 #define KTIME_MAX			((s64)~((u64)1 << 63))
31 #define KTIME_MIN			(-KTIME_MAX - 1)
32 #define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
33 #define KTIME_SEC_MIN			(KTIME_MIN / NSEC_PER_SEC)
34 
35 /*
36  * Limits for settimeofday():
37  *
38  * To prevent setting the time close to the wraparound point time setting
39  * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
40  * should be really sufficient, which means the cutoff is 2232. At that
41  * point the cutoff is just a small part of the larger problem.
42  */
43 #define TIME_UPTIME_SEC_MAX		(30LL * 365 * 24 *3600)
44 #define TIME_SETTOD_SEC_MAX		(KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
45 
timespec64_equal(const struct timespec64 * a,const struct timespec64 * b)46 static inline int timespec64_equal(const struct timespec64 *a,
47 				   const struct timespec64 *b)
48 {
49 	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
50 }
51 
52 /*
53  * lhs < rhs:  return <0
54  * lhs == rhs: return 0
55  * lhs > rhs:  return >0
56  */
timespec64_compare(const struct timespec64 * lhs,const struct timespec64 * rhs)57 static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
58 {
59 	if (lhs->tv_sec < rhs->tv_sec)
60 		return -1;
61 	if (lhs->tv_sec > rhs->tv_sec)
62 		return 1;
63 	return lhs->tv_nsec - rhs->tv_nsec;
64 }
65 
66 extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
67 
timespec64_add(struct timespec64 lhs,struct timespec64 rhs)68 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
69 						struct timespec64 rhs)
70 {
71 	struct timespec64 ts_delta;
72 	set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
73 				lhs.tv_nsec + rhs.tv_nsec);
74 	return ts_delta;
75 }
76 
77 /*
78  * sub = lhs - rhs, in normalized form
79  */
timespec64_sub(struct timespec64 lhs,struct timespec64 rhs)80 static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
81 						struct timespec64 rhs)
82 {
83 	struct timespec64 ts_delta;
84 	set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
85 				lhs.tv_nsec - rhs.tv_nsec);
86 	return ts_delta;
87 }
88 
89 /*
90  * Returns true if the timespec64 is norm, false if denorm:
91  */
timespec64_valid(const struct timespec64 * ts)92 static inline bool timespec64_valid(const struct timespec64 *ts)
93 {
94 	/* Dates before 1970 are bogus */
95 	if (ts->tv_sec < 0)
96 		return false;
97 	/* Can't have more nanoseconds then a second */
98 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
99 		return false;
100 	return true;
101 }
102 
timespec64_valid_strict(const struct timespec64 * ts)103 static inline bool timespec64_valid_strict(const struct timespec64 *ts)
104 {
105 	if (!timespec64_valid(ts))
106 		return false;
107 	/* Disallow values that could overflow ktime_t */
108 	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
109 		return false;
110 	return true;
111 }
112 
timespec64_valid_settod(const struct timespec64 * ts)113 static inline bool timespec64_valid_settod(const struct timespec64 *ts)
114 {
115 	if (!timespec64_valid(ts))
116 		return false;
117 	/* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
118 	if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
119 		return false;
120 	return true;
121 }
122 
123 /**
124  * timespec64_to_ns - Convert timespec64 to nanoseconds
125  * @ts:		pointer to the timespec64 variable to be converted
126  *
127  * Returns the scalar nanosecond representation of the timespec64
128  * parameter.
129  */
timespec64_to_ns(const struct timespec64 * ts)130 static inline s64 timespec64_to_ns(const struct timespec64 *ts)
131 {
132 	/* Prevent multiplication overflow / underflow */
133 	if (ts->tv_sec >= KTIME_SEC_MAX)
134 		return KTIME_MAX;
135 
136 	if (ts->tv_sec <= KTIME_SEC_MIN)
137 		return KTIME_MIN;
138 
139 	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
140 }
141 
142 /**
143  * ns_to_timespec64 - Convert nanoseconds to timespec64
144  * @nsec:	the nanoseconds value to be converted
145  *
146  * Returns the timespec64 representation of the nsec parameter.
147  */
148 extern struct timespec64 ns_to_timespec64(s64 nsec);
149 
150 /**
151  * timespec64_add_ns - Adds nanoseconds to a timespec64
152  * @a:		pointer to timespec64 to be incremented
153  * @ns:		unsigned nanoseconds value to be added
154  *
155  * This must always be inlined because its used from the x86-64 vdso,
156  * which cannot call other kernel functions.
157  */
timespec64_add_ns(struct timespec64 * a,u64 ns)158 static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
159 {
160 	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
161 	a->tv_nsec = ns;
162 }
163 
164 /*
165  * timespec64_add_safe assumes both values are positive and checks for
166  * overflow. It will return TIME64_MAX in case of overflow.
167  */
168 extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
169 					 const struct timespec64 rhs);
170 
171 #endif /* _LINUX_TIME64_H */
172