2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
11 * fasttime.c -- Get the time of day quickly by mapping the kernel's
12 * time of day variable.
16 * Modification History
17 * 3/21/86: Added FT_ApproxTime which returns the last time
18 * in seconds returned by RT_FastTime. The intent is to give
19 * routines which aren't too concerned about the exact time
20 * fast access to the time, even on kernels without mmap.
21 * 4/2/86: Fixed my previous mod and fixed FT_Init so it doesn't initialize
22 * a second time if explicitly called after being implicitly called.
23 * This saves a (precious) file descriptor.
26 #include <afsconfig.h>
27 #include <afs/param.h>
31 #include <afs/afsutil.h>
38 static enum InitState { notTried, tried, done } initState = notTried;
40 struct timeval FT_LastTime; /* last time returned by RT_FastTime. Used to implement
44 /* Call this to get the memory mapped. It will return -1 if anything went
45 wrong. In that case, calls to FT_GetTimeOfDay will call gettimeofday
46 instead. If printErrors is true, errors in initialization will cause
47 error messages to be printed on stderr. If notReally is true, then
48 things are set up so that all calls to FT_GetTimeOfDay call gettimeofday.
49 You might want this if your program won't run too long and the nlist
50 call is too expensive. Yeah, it's pretty horrible.
53 FT_Init(int printErrors, int notReally)
55 if (initState != notTried && !notReally)
56 return (initState == done ? 0 : -1); /* This is in case explicit initialization
57 * occurs after automatic initialization */
60 return 0; /* fake success, but leave initState
63 fprintf(stderr, "FT_Init: mmap not implemented on this kernel\n");
67 /* Call this to get the time of day. It will automatically initialize the
68 first time you call it. If you want error messages when you initialize,
69 call FT_Init yourself. If the initialization failed, this will just
70 call gettimeofday. If you ask for the timezone info, this routine will
71 punt to gettimeofday. */
73 FT_GetTimeOfDay(struct timeval *tv, struct timezone *tz)
76 ret = gettimeofday(tv, tz);
78 /* need to bounds check 'cause Unix can fail these checks, (esp on Suns)
79 * and time package can generate invalid (to select syscall) values
80 * for the time until the next interesting event if it encounters
81 * out of range microsecond fields */
84 if (tv->tv_usec > 999999)
86 FT_LastTime.tv_sec = tv->tv_sec;
87 FT_LastTime.tv_usec = tv->tv_usec;
93 /* For compatibility. Should go away. */
95 TM_GetTimeOfDay(struct timeval *tv, struct timezone *tz)
97 return FT_GetTimeOfDay(tv, tz);
101 FT_AGetTimeOfDay(struct timeval *tv, struct timezone *tz)
103 if (FT_LastTime.tv_sec) {
104 tv->tv_sec = FT_LastTime.tv_sec;
105 tv->tv_usec = FT_LastTime.tv_usec;
108 return FT_GetTimeOfDay(tv, tz);
111 #ifdef AFS_PTHREAD_ENV
112 unsigned int FT_ApproxTime(void)
120 if (!FT_LastTime.tv_sec) {
121 FT_GetTimeOfDay(&FT_LastTime, 0);
123 return FT_LastTime.tv_sec;