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Linux/include/linux/time64.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef _LINUX_TIME64_H
  3 #define _LINUX_TIME64_H
  4 
  5 #include <linux/math64.h>
  6 
  7 typedef __s64 time64_t;
  8 typedef __u64 timeu64_t;
  9 
 10 #include <uapi/linux/time.h>
 11 
 12 struct timespec64 {
 13         time64_t        tv_sec;                 /* seconds */
 14         long            tv_nsec;                /* nanoseconds */
 15 };
 16 
 17 struct itimerspec64 {
 18         struct timespec64 it_interval;
 19         struct timespec64 it_value;
 20 };
 21 
 22 /* Parameters used to convert the timespec values: */
 23 #define MSEC_PER_SEC    1000L
 24 #define USEC_PER_MSEC   1000L
 25 #define NSEC_PER_USEC   1000L
 26 #define NSEC_PER_MSEC   1000000L
 27 #define USEC_PER_SEC    1000000L
 28 #define NSEC_PER_SEC    1000000000L
 29 #define FSEC_PER_SEC    1000000000000000LL
 30 
 31 /* Located here for timespec[64]_valid_strict */
 32 #define TIME64_MAX                      ((s64)~((u64)1 << 63))
 33 #define KTIME_MAX                       ((s64)~((u64)1 << 63))
 34 #define KTIME_SEC_MAX                   (KTIME_MAX / NSEC_PER_SEC)
 35 
 36 /*
 37  * Limits for settimeofday():
 38  *
 39  * To prevent setting the time close to the wraparound point time setting
 40  * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
 41  * should be really sufficient, which means the cutoff is 2232. At that
 42  * point the cutoff is just a small part of the larger problem.
 43  */
 44 #define TIME_UPTIME_SEC_MAX             (30LL * 365 * 24 *3600)
 45 #define TIME_SETTOD_SEC_MAX             (KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
 46 
 47 static inline int timespec64_equal(const struct timespec64 *a,
 48                                    const struct timespec64 *b)
 49 {
 50         return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
 51 }
 52 
 53 /*
 54  * lhs < rhs:  return <0
 55  * lhs == rhs: return 0
 56  * lhs > rhs:  return >0
 57  */
 58 static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
 59 {
 60         if (lhs->tv_sec < rhs->tv_sec)
 61                 return -1;
 62         if (lhs->tv_sec > rhs->tv_sec)
 63                 return 1;
 64         return lhs->tv_nsec - rhs->tv_nsec;
 65 }
 66 
 67 extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
 68 
 69 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
 70                                                 struct timespec64 rhs)
 71 {
 72         struct timespec64 ts_delta;
 73         set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
 74                                 lhs.tv_nsec + rhs.tv_nsec);
 75         return ts_delta;
 76 }
 77 
 78 /*
 79  * sub = lhs - rhs, in normalized form
 80  */
 81 static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
 82                                                 struct timespec64 rhs)
 83 {
 84         struct timespec64 ts_delta;
 85         set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
 86                                 lhs.tv_nsec - rhs.tv_nsec);
 87         return ts_delta;
 88 }
 89 
 90 /*
 91  * Returns true if the timespec64 is norm, false if denorm:
 92  */
 93 static inline bool timespec64_valid(const struct timespec64 *ts)
 94 {
 95         /* Dates before 1970 are bogus */
 96         if (ts->tv_sec < 0)
 97                 return false;
 98         /* Can't have more nanoseconds then a second */
 99         if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
100                 return false;
101         return true;
102 }
103 
104 static inline bool timespec64_valid_strict(const struct timespec64 *ts)
105 {
106         if (!timespec64_valid(ts))
107                 return false;
108         /* Disallow values that could overflow ktime_t */
109         if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
110                 return false;
111         return true;
112 }
113 
114 static inline bool timespec64_valid_settod(const struct timespec64 *ts)
115 {
116         if (!timespec64_valid(ts))
117                 return false;
118         /* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
119         if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
120                 return false;
121         return true;
122 }
123 
124 /**
125  * timespec64_to_ns - Convert timespec64 to nanoseconds
126  * @ts:         pointer to the timespec64 variable to be converted
127  *
128  * Returns the scalar nanosecond representation of the timespec64
129  * parameter.
130  */
131 static inline s64 timespec64_to_ns(const struct timespec64 *ts)
132 {
133         return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
134 }
135 
136 /**
137  * ns_to_timespec64 - Convert nanoseconds to timespec64
138  * @nsec:       the nanoseconds value to be converted
139  *
140  * Returns the timespec64 representation of the nsec parameter.
141  */
142 extern struct timespec64 ns_to_timespec64(const s64 nsec);
143 
144 /**
145  * timespec64_add_ns - Adds nanoseconds to a timespec64
146  * @a:          pointer to timespec64 to be incremented
147  * @ns:         unsigned nanoseconds value to be added
148  *
149  * This must always be inlined because its used from the x86-64 vdso,
150  * which cannot call other kernel functions.
151  */
152 static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
153 {
154         a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
155         a->tv_nsec = ns;
156 }
157 
158 /*
159  * timespec64_add_safe assumes both values are positive and checks for
160  * overflow. It will return TIME64_MAX in case of overflow.
161  */
162 extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
163                                          const struct timespec64 rhs);
164 
165 #endif /* _LINUX_TIME64_H */
166 

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