source: branches/3.2/mindi-busybox/util-linux/rtcwake.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 6.8 KB
Line 
1/*
2 * rtcwake -- enter a system sleep state until specified wakeup time.
3 *
4 * This version was taken from util-linux and scrubbed down for busybox.
5 *
6 * Licensed under GPLv2, see file LICENSE in this source tree.
7 *
8 * This uses cross-platform Linux interfaces to enter a system sleep state,
9 * and leave it no later than a specified time.  It uses any RTC framework
10 * driver that supports standard driver model wakeup flags.
11 *
12 * This is normally used like the old "apmsleep" utility, to wake from a
13 * suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM).  Most
14 * platforms can implement those without analogues of BIOS, APM, or ACPI.
15 *
16 * On some systems, this can also be used like "nvram-wakeup", waking
17 * from states like ACPI S4 (suspend to disk).  Not all systems have
18 * persistent media that are appropriate for such suspend modes.
19 *
20 * The best way to set the system's RTC is so that it holds the current
21 * time in UTC.  Use the "-l" flag to tell this program that the system
22 * RTC uses a local timezone instead (maybe you dual-boot MS-Windows).
23 * That flag should not be needed on systems with adjtime support.
24 */
25
26//usage:#define rtcwake_trivial_usage
27//usage:       "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
28//usage:#define rtcwake_full_usage "\n\n"
29//usage:       "Enter a system sleep state until specified wakeup time\n"
30//usage:    IF_LONG_OPTS(
31//usage:     "\n    -a,--auto   Read clock mode from adjtime"
32//usage:     "\n    -l,--local  Clock is set to local time"
33//usage:     "\n    -u,--utc    Clock is set to UTC time"
34//usage:     "\n    -d,--device=DEV Specify the RTC device"
35//usage:     "\n    -m,--mode=MODE  Set the sleep state (default: standby)"
36//usage:     "\n    -s,--seconds=SEC Set the timeout in SEC seconds from now"
37//usage:     "\n    -t,--time=TIME  Set the timeout to TIME seconds from epoch"
38//usage:    )
39//usage:    IF_NOT_LONG_OPTS(
40//usage:     "\n    -a  Read clock mode from adjtime"
41//usage:     "\n    -l  Clock is set to local time"
42//usage:     "\n    -u  Clock is set to UTC time"
43//usage:     "\n    -d DEV  Specify the RTC device"
44//usage:     "\n    -m MODE Set the sleep state (default: standby)"
45//usage:     "\n    -s SEC  Set the timeout in SEC seconds from now"
46//usage:     "\n    -t TIME Set the timeout to TIME seconds from epoch"
47//usage:    )
48
49#include "libbb.h"
50#include "rtc_.h"
51
52#define SYS_RTC_PATH   "/sys/class/rtc/%s/device/power/wakeup"
53#define SYS_POWER_PATH "/sys/power/state"
54#define DEFAULT_MODE   "standby"
55
56static NOINLINE bool may_wakeup(const char *rtcname)
57{
58    ssize_t ret;
59    char buf[128];
60
61    /* strip "/dev/" from the rtcname here */
62    rtcname = skip_dev_pfx(rtcname);
63
64    snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
65    ret = open_read_close(buf, buf, sizeof(buf));
66    if (ret < 0)
67        return false;
68
69    /* wakeup events could be disabled or not supported */
70    return strncmp(buf, "enabled\n", 8) == 0;
71}
72
73static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
74{
75    struct tm *ptm;
76    struct linux_rtc_wkalrm wake;
77
78    /* The wakeup time is in POSIX time (more or less UTC).
79     * Ideally RTCs use that same time; but PCs can't do that
80     * if they need to boot MS-Windows.  Messy...
81     *
82     * When running in utc mode this process's timezone is UTC,
83     * so we'll pass a UTC date to the RTC.
84     *
85     * Else mode is local so the time given to the RTC
86     * will instead use the local time zone.
87     */
88    ptm = localtime(wakeup);
89
90    wake.time.tm_sec = ptm->tm_sec;
91    wake.time.tm_min = ptm->tm_min;
92    wake.time.tm_hour = ptm->tm_hour;
93    wake.time.tm_mday = ptm->tm_mday;
94    wake.time.tm_mon = ptm->tm_mon;
95    wake.time.tm_year = ptm->tm_year;
96    /* wday, yday, and isdst fields are unused by Linux */
97    wake.time.tm_wday = -1;
98    wake.time.tm_yday = -1;
99    wake.time.tm_isdst = -1;
100
101    /* many rtc alarms only support up to 24 hours from 'now',
102     * so use the "more than 24 hours" request only if we must
103     */
104    if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
105        xioctl(fd, RTC_ALM_SET, &wake.time);
106        xioctl(fd, RTC_AIE_ON, 0);
107    } else {
108        /* avoid an extra AIE_ON call */
109        wake.enabled = 1;
110        xioctl(fd, RTC_WKALM_SET, &wake);
111    }
112}
113
114#define RTCWAKE_OPT_AUTO         0x01
115#define RTCWAKE_OPT_LOCAL        0x02
116#define RTCWAKE_OPT_UTC          0x04
117#define RTCWAKE_OPT_DEVICE       0x08
118#define RTCWAKE_OPT_SUSPEND_MODE 0x10
119#define RTCWAKE_OPT_SECONDS      0x20
120#define RTCWAKE_OPT_TIME         0x40
121
122int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
123int rtcwake_main(int argc UNUSED_PARAM, char **argv)
124{
125    time_t rtc_time;
126
127    unsigned opt;
128    const char *rtcname = NULL;
129    const char *suspend;
130    const char *opt_seconds;
131    const char *opt_time;
132
133    time_t sys_time;
134    time_t alarm_time = 0;
135    unsigned seconds = 0;
136    int utc = -1;
137    int fd;
138
139#if ENABLE_LONG_OPTS
140    static const char rtcwake_longopts[] ALIGN1 =
141        "auto\0"    No_argument "a"
142        "local\0"   No_argument "l"
143        "utc\0"     No_argument "u"
144        "device\0"  Required_argument "d"
145        "mode\0"    Required_argument "m"
146        "seconds\0" Required_argument "s"
147        "time\0"    Required_argument "t"
148        ;
149    applet_long_options = rtcwake_longopts;
150#endif
151    opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time);
152
153    /* this is the default
154    if (opt & RTCWAKE_OPT_AUTO)
155        utc = -1;
156    */
157    if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
158        utc = opt & RTCWAKE_OPT_UTC;
159    if (!(opt & RTCWAKE_OPT_SUSPEND_MODE))
160        suspend = DEFAULT_MODE;
161    if (opt & RTCWAKE_OPT_SECONDS)
162        /* alarm time, seconds-to-sleep (relative) */
163        seconds = xatoi(opt_seconds);
164    if (opt & RTCWAKE_OPT_TIME)
165        /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
166        alarm_time = xatol(opt_time);
167
168    if (!alarm_time && !seconds)
169        bb_error_msg_and_die("must provide wake time");
170
171    if (utc == -1)
172        utc = rtc_adjtime_is_utc();
173
174    /* the rtcname is relative to /dev */
175    xchdir("/dev");
176
177    /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
178    fd = rtc_xopen(&rtcname, O_RDONLY);
179
180    if (strcmp(suspend, "on") && !may_wakeup(rtcname))
181        bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
182
183    /* relative or absolute alarm time, normalized to time_t */
184    sys_time = time(NULL);
185    {
186        struct tm tm_time;
187        rtc_read_tm(&tm_time, fd);
188        rtc_time = rtc_tm2time(&tm_time, utc);
189    }
190
191
192    if (alarm_time) {
193        if (alarm_time < sys_time)
194            bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
195        alarm_time += sys_time - rtc_time;
196    } else
197        alarm_time = rtc_time + seconds + 1;
198    setup_alarm(fd, &alarm_time, rtc_time);
199
200    sync();
201    printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
202    fflush_all();
203    usleep(10 * 1000);
204
205    if (strcmp(suspend, "on"))
206        xopen_xwrite_close(SYS_POWER_PATH, suspend);
207    else {
208        /* "fake" suspend ... we'll do the delay ourselves */
209        unsigned long data;
210
211        do {
212            ssize_t ret = safe_read(fd, &data, sizeof(data));
213            if (ret < 0) {
214                bb_perror_msg("rtc read");
215                break;
216            }
217        } while (!(data & RTC_AF));
218    }
219
220    xioctl(fd, RTC_AIE_OFF, 0);
221
222    if (ENABLE_FEATURE_CLEAN_UP)
223        close(fd);
224
225    return EXIT_SUCCESS;
226}
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