include/linux/time.h

   1 #ifndef _LINUX_TIME_H
   2 #define _LINUX_TIME_H
   3
   4 # include <linux/cache.h>
   5 # include <linux/seqlock.h>
   6 # include <linux/math64.h>
   7 # include <linux/time64.h>
   8
   9 extern struct timezone sys_tz;
  10
  11 #define TIME_T_MAX      (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
  12
  13 static inline int timespec_equal(const struct timespec *a,
  14                                  const struct timespec *b)
  15 {
  16         return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
  17 }
  18
  19 /*
  20  * lhs < rhs:  return <0
  21  * lhs == rhs: return 0
  22  * lhs > rhs:  return >0
  23  */
  24 static inline int timespec_compare(const struct timespec *lhs, const struct timespec *rhs)
  25 {
  26         if (lhs->tv_sec < rhs->tv_sec)
  27                 return -1;
  28         if (lhs->tv_sec > rhs->tv_sec)
  29                 return 1;
  30         return lhs->tv_nsec - rhs->tv_nsec;
  31 }
  32
  33 static inline int timeval_compare(const struct timeval *lhs, const struct timeval *rhs)
  34 {
  35         if (lhs->tv_sec < rhs->tv_sec)
  36                 return -1;
  37         if (lhs->tv_sec > rhs->tv_sec)
  38                 return 1;
  39         return lhs->tv_usec - rhs->tv_usec;
  40 }
  41
  42 extern time64_t mktime64(const unsigned int year, const unsigned int mon,
  43                         const unsigned int day, const unsigned int hour,
  44                         const unsigned int min, const unsigned int sec);
  45
  46 /**
  47  * Deprecated. Use mktime64().
  48  */
  49 static inline unsigned long mktime(const unsigned int year,
  50                         const unsigned int mon, const unsigned int day,
  51                         const unsigned int hour, const unsigned int min,
  52                         const unsigned int sec)
  53 {
  54         return mktime64(year, mon, day, hour, min, sec);
  55 }
  56
  57 extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);
  58
  59 /*
  60  * timespec_add_safe assumes both values are positive and checks
  61  * for overflow. It will return TIME_T_MAX if the reutrn would be
  62  * smaller then either of the arguments.
  63  */
  64 extern struct timespec timespec_add_safe(const struct timespec lhs,
  65                                          const struct timespec rhs);
  66
  67
  68 static inline struct timespec timespec_add(struct timespec lhs,
  69                                                 struct timespec rhs)
  70 {
  71         struct timespec ts_delta;
  72         set_normalized_timespec(&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  */
  80 static inline struct timespec timespec_sub(struct timespec lhs,
  81                                                 struct timespec rhs)
  82 {
  83         struct timespec ts_delta;
  84         set_normalized_timespec(&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 timespec is norm, false if denorm:
  91  */
  92 static inline bool timespec_valid(const struct timespec *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
 103 static inline bool timespec_valid_strict(const struct timespec *ts)
 104 {
 105         if (!timespec_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
 113 static inline bool timeval_valid(const struct timeval *tv)
 114 {
 115         /* Dates before 1970 are bogus */
 116         if (tv->tv_sec < 0)
 117                 return false;
 118
 119         /* Can't have more microseconds then a second */
 120         if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
 121                 return false;
 122
 123         return true;
 124 }
 125
 126 extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
 127
 128 /*
 129  * Validates if a timespec/timeval used to inject a time offset is valid.
 130  * Offsets can be postive or negative. The value of the timeval/timespec
 131  * is the sum of its fields, but *NOTE*: the field tv_usec/tv_nsec must
 132  * always be non-negative.
 133  */
 134 static inline bool timeval_inject_offset_valid(const struct timeval *tv)
 135 {
 136         /* We don't check the tv_sec as it can be positive or negative */
 137
 138         /* Can't have more microseconds then a second */
 139         if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
 140                 return false;
 141         return true;
 142 }
 143
 144 static inline bool timespec_inject_offset_valid(const struct timespec *ts)
 145 {
 146         /* We don't check the tv_sec as it can be positive or negative */
 147
 148         /* Can't have more nanoseconds then a second */
 149         if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
 150                 return false;
 151         return true;
 152 }
 153
 154 /* Some architectures do not supply their own clocksource.
 155  * This is mainly the case in architectures that get their
 156  * inter-tick times by reading the counter on their interval
 157  * timer. Since these timers wrap every tick, they're not really
 158  * useful as clocksources. Wrapping them to act like one is possible
 159  * but not very efficient. So we provide a callout these arches
 160  * can implement for use with the jiffies clocksource to provide
 161  * finer then tick granular time.
 162  */
 163 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 164 extern u32 (*arch_gettimeoffset)(void);
 165 #endif
 166
 167 struct itimerval;
 168 extern int do_setitimer(int which, struct itimerval *value,
 169                         struct itimerval *ovalue);
 170 extern int do_getitimer(int which, struct itimerval *value);
 171
 172 extern long do_utimes(int dfd, const char __user *filename, struct timespec *times, int flags);
 173
 174 struct tms;
 175 extern void do_sys_times(struct tms *);
 176
 177 /*
 178  * Similar to the struct tm in userspace <time.h>, but it needs to be here so
 179  * that the kernel source is self contained.
 180  */
 181 struct tm {
 182         /*
 183          * the number of seconds after the minute, normally in the range
 184          * 0 to 59, but can be up to 60 to allow for leap seconds
 185          */
 186         int tm_sec;
 187         /* the number of minutes after the hour, in the range 0 to 59*/
 188         int tm_min;
 189         /* the number of hours past midnight, in the range 0 to 23 */
 190         int tm_hour;
 191         /* the day of the month, in the range 1 to 31 */
 192         int tm_mday;
 193         /* the number of months since January, in the range 0 to 11 */
 194         int tm_mon;
 195         /* the number of years since 1900 */
 196         long tm_year;
 197         /* the number of days since Sunday, in the range 0 to 6 */
 198         int tm_wday;
 199         /* the number of days since January 1, in the range 0 to 365 */
 200         int tm_yday;
 201 };
 202
 203 void time64_to_tm(time64_t totalsecs, int offset, struct tm *result);
 204
 205 /**
 206  * time_to_tm - converts the calendar time to local broken-down time
 207  *
 208  * @totalsecs   the number of seconds elapsed since 00:00:00 on January 1, 1970,
 209  *              Coordinated Universal Time (UTC).
 210  * @offset      offset seconds adding to totalsecs.
 211  * @result      pointer to struct tm variable to receive broken-down time
 212  */
 213 static inline void time_to_tm(time_t totalsecs, int offset, struct tm *result)
 214 {
 215         time64_to_tm(totalsecs, offset, result);
 216 }
 217
 218 /**
 219  * timespec_to_ns - Convert timespec to nanoseconds
 220  * @ts:         pointer to the timespec variable to be converted
 221  *
 222  * Returns the scalar nanosecond representation of the timespec
 223  * parameter.
 224  */
 225 static inline s64 timespec_to_ns(const struct timespec *ts)
 226 {
 227         return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
 228 }
 229
 230 /**
 231  * timeval_to_ns - Convert timeval to nanoseconds
 232  * @ts:         pointer to the timeval variable to be converted
 233  *
 234  * Returns the scalar nanosecond representation of the timeval
 235  * parameter.
 236  */
 237 static inline s64 timeval_to_ns(const struct timeval *tv)
 238 {
 239         return ((s64) tv->tv_sec * NSEC_PER_SEC) +
 240                 tv->tv_usec * NSEC_PER_USEC;
 241 }
 242
 243 /**
 244  * ns_to_timespec - Convert nanoseconds to timespec
 245  * @nsec:       the nanoseconds value to be converted
 246  *
 247  * Returns the timespec representation of the nsec parameter.
 248  */
 249 extern struct timespec ns_to_timespec(const s64 nsec);
 250
 251 /**
 252  * ns_to_timeval - Convert nanoseconds to timeval
 253  * @nsec:       the nanoseconds value to be converted
 254  *
 255  * Returns the timeval representation of the nsec parameter.
 256  */
 257 extern struct timeval ns_to_timeval(const s64 nsec);
 258
 259 /**
 260  * timespec_add_ns - Adds nanoseconds to a timespec
 261  * @a:          pointer to timespec to be incremented
 262  * @ns:         unsigned nanoseconds value to be added
 263  *
 264  * This must always be inlined because its used from the x86-64 vdso,
 265  * which cannot call other kernel functions.
 266  */
 267 static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
 268 {
 269         a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
 270         a->tv_nsec = ns;
 271 }
 272
 273 #endif