SystemClock.cpp revision 9d4536835248525f32f1504a3d28d5bbfa0a2910 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17
18/*
19 * System clock functions.
20 */
21
22#ifdef HAVE_ANDROID_OS
23#include <linux/ioctl.h>
24#include <linux/rtc.h>
25#include <utils/Atomic.h>
26#include <linux/android_alarm.h>
27#endif
28
29#include <sys/time.h>
30#include <limits.h>
31#include <fcntl.h>
32#include <errno.h>
33#include <string.h>
34
35#include <utils/SystemClock.h>
36#include <utils/Timers.h>
37
38#define LOG_TAG "SystemClock"
39#include "utils/Log.h"
40
41namespace android {
42
43/*
44 * Set the current time.  This only works when running as root.
45 */
46int setCurrentTimeMillis(int64_t millis)
47{
48#if WIN32
49    // not implemented
50    return -1;
51#else
52    struct timeval tv;
53#ifdef HAVE_ANDROID_OS
54    struct timespec ts;
55    int fd;
56    int res;
57#endif
58    int ret = 0;
59
60    if (millis <= 0 || millis / 1000LL >= INT_MAX) {
61        return -1;
62    }
63
64    tv.tv_sec = (time_t) (millis / 1000LL);
65    tv.tv_usec = (suseconds_t) ((millis % 1000LL) * 1000LL);
66
67    ALOGD("Setting time of day to sec=%d\n", (int) tv.tv_sec);
68
69#ifdef HAVE_ANDROID_OS
70    fd = open("/dev/alarm", O_RDWR);
71    if(fd < 0) {
72        LOGW("Unable to open alarm driver: %s\n", strerror(errno));
73        return -1;
74    }
75    ts.tv_sec = tv.tv_sec;
76    ts.tv_nsec = tv.tv_usec * 1000;
77    res = ioctl(fd, ANDROID_ALARM_SET_RTC, &ts);
78    if(res < 0) {
79        LOGW("Unable to set rtc to %ld: %s\n", tv.tv_sec, strerror(errno));
80        ret = -1;
81    }
82    close(fd);
83#else
84    if (settimeofday(&tv, NULL) != 0) {
85        LOGW("Unable to set clock to %d.%d: %s\n",
86            (int) tv.tv_sec, (int) tv.tv_usec, strerror(errno));
87        ret = -1;
88    }
89#endif
90
91    return ret;
92#endif // WIN32
93}
94
95/*
96 * native public static long uptimeMillis();
97 */
98int64_t uptimeMillis()
99{
100    int64_t when = systemTime(SYSTEM_TIME_MONOTONIC);
101    return (int64_t) nanoseconds_to_milliseconds(when);
102}
103
104/*
105 * native public static long elapsedRealtime();
106 */
107int64_t elapsedRealtime()
108{
109#ifdef HAVE_ANDROID_OS
110    static int s_fd = -1;
111
112    if (s_fd == -1) {
113        int fd = open("/dev/alarm", O_RDONLY);
114        if (android_atomic_cmpxchg(-1, fd, &s_fd)) {
115            close(fd);
116        }
117    }
118
119    struct timespec ts;
120    int result = ioctl(s_fd,
121            ANDROID_ALARM_GET_TIME(ANDROID_ALARM_ELAPSED_REALTIME), &ts);
122
123    if (result == 0) {
124        int64_t when = seconds_to_nanoseconds(ts.tv_sec) + ts.tv_nsec;
125        return (int64_t) nanoseconds_to_milliseconds(when);
126    } else {
127        // XXX: there was an error, probably because the driver didn't
128        // exist ... this should return
129        // a real error, like an exception!
130        int64_t when = systemTime(SYSTEM_TIME_MONOTONIC);
131        return (int64_t) nanoseconds_to_milliseconds(when);
132    }
133#else
134    int64_t when = systemTime(SYSTEM_TIME_MONOTONIC);
135    return (int64_t) nanoseconds_to_milliseconds(when);
136#endif
137}
138
139}; // namespace android
140