src/util/os_time.c

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  27
  28 /**
  29  * @file
  30  * OS independent time-manipulation functions.
  31  *
  32  * @author Jose Fonseca <jfonseca@vmware.com>
  33  */
  34
  35 #include "os_time.h"
  36 #include "detect_os.h"
  37
  38 #include "util/u_atomic.h"
  39
  40 #if DETECT_OS_UNIX
  41 #  include <unistd.h> /* usleep */
  42 #  include <time.h> /* timeval */
  43 #  include <sys/time.h> /* timeval */
  44 #  include <sched.h> /* sched_yield */
  45 #  include <errno.h>
  46 #elif DETECT_OS_WINDOWS
  47 #  include <windows.h>
  48 #else
  49 #  error Unsupported OS
  50 #endif
  51
  52
  53 int64_t
  54 os_time_get_nano(void)
  55 {
  56 #if DETECT_OS_LINUX || DETECT_OS_BSD
  57
  58    struct timespec tv;
  59    clock_gettime(CLOCK_MONOTONIC, &tv);
  60    return tv.tv_nsec + tv.tv_sec*INT64_C(1000000000);
  61
  62 #elif DETECT_OS_UNIX
  63
  64    struct timeval tv;
  65    gettimeofday(&tv, NULL);
  66    return tv.tv_usec*INT64_C(1000) + tv.tv_sec*INT64_C(1000000000);
  67
  68 #elif DETECT_OS_WINDOWS
  69
  70    static LARGE_INTEGER frequency;
  71    LARGE_INTEGER counter;
  72    int64_t secs, nanosecs;
  73    if(!frequency.QuadPart)
  74       QueryPerformanceFrequency(&frequency);
  75    QueryPerformanceCounter(&counter);
  76    /* Compute seconds and nanoseconds parts separately to
  77     * reduce severity of precision loss.
  78     */
  79    secs = counter.QuadPart / frequency.QuadPart;
  80    nanosecs = (counter.QuadPart % frequency.QuadPart) * INT64_C(1000000000)
  81       / frequency.QuadPart;
  82    return secs*INT64_C(1000000000) + nanosecs;
  83
  84 #else
  85
  86 #error Unsupported OS
  87
  88 #endif
  89 }
  90
  91
  92
  93 void
  94 os_time_sleep(int64_t usecs)
  95 {
  96 #if DETECT_OS_LINUX
  97    struct timespec time;
  98    time.tv_sec = usecs / 1000000;
  99    time.tv_nsec = (usecs % 1000000) * 1000;
 100    while (clock_nanosleep(CLOCK_MONOTONIC, 0, &time, &time) == EINTR);
 101
 102 #elif DETECT_OS_UNIX
 103    usleep(usecs);
 104
 105 #elif DETECT_OS_WINDOWS
 106    DWORD dwMilliseconds = (DWORD) ((usecs + 999) / 1000);
 107    /* Avoid Sleep(O) as that would cause to sleep for an undetermined duration */
 108    if (dwMilliseconds) {
 109       Sleep(dwMilliseconds);
 110    }
 111 #else
 112 #  error Unsupported OS
 113 #endif
 114 }
 115
 116
 117
 118 int64_t
 119 os_time_get_absolute_timeout(uint64_t timeout)
 120 {
 121    int64_t time, abs_timeout;
 122
 123    /* Also check for the type upper bound. */
 124    if (timeout == OS_TIMEOUT_INFINITE || timeout > INT64_MAX)
 125       return OS_TIMEOUT_INFINITE;
 126
 127    time = os_time_get_nano();
 128    abs_timeout = time + (int64_t)timeout;
 129
 130    /* Check for overflow. */
 131    if (abs_timeout < time)
 132       return OS_TIMEOUT_INFINITE;
 133
 134    return abs_timeout;
 135 }
 136
 137
 138 bool
 139 os_wait_until_zero(volatile int *var, uint64_t timeout)
 140 {
 141    if (!p_atomic_read(var))
 142       return true;
 143
 144    if (!timeout)
 145       return false;
 146
 147    if (timeout == OS_TIMEOUT_INFINITE) {
 148       while (p_atomic_read(var)) {
 149 #if DETECT_OS_UNIX
 150          sched_yield();
 151 #endif
 152       }
 153       return true;
 154    }
 155    else {
 156       int64_t start_time = os_time_get_nano();
 157       int64_t end_time = start_time + timeout;
 158
 159       while (p_atomic_read(var)) {
 160          if (os_time_timeout(start_time, end_time, os_time_get_nano()))
 161             return false;
 162
 163 #if DETECT_OS_UNIX
 164          sched_yield();
 165 #endif
 166       }
 167       return true;
 168    }
 169 }
 170
 171
 172 bool
 173 os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout)
 174 {
 175    if (!p_atomic_read(var))
 176       return true;
 177
 178    if (timeout == OS_TIMEOUT_INFINITE)
 179       return os_wait_until_zero(var, OS_TIMEOUT_INFINITE);
 180
 181    while (p_atomic_read(var)) {
 182       if (os_time_get_nano() >= timeout)
 183          return false;
 184
 185 #if DETECT_OS_UNIX
 186       sched_yield();
 187 #endif
 188    }
 189    return true;
 190 }