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path: root/util-linux/rtcwake.c (plain)
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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//config:config RTCWAKE
26//config: bool "rtcwake"
27//config: default y
28//config: select PLATFORM_LINUX
29//config: help
30//config: Enter a system sleep state until specified wakeup time.
31
32//applet:IF_RTCWAKE(APPLET(rtcwake, BB_DIR_USR_SBIN, BB_SUID_DROP))
33
34//kbuild:lib-$(CONFIG_RTCWAKE) += rtcwake.o
35
36//usage:#define rtcwake_trivial_usage
37//usage: "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
38//usage:#define rtcwake_full_usage "\n\n"
39//usage: "Enter a system sleep state until specified wakeup time\n"
40//usage: IF_LONG_OPTS(
41//usage: "\n -a,--auto Read clock mode from adjtime"
42//usage: "\n -l,--local Clock is set to local time"
43//usage: "\n -u,--utc Clock is set to UTC time"
44//usage: "\n -d,--device=DEV Specify the RTC device"
45//usage: "\n -m,--mode=MODE Set sleep state (default: standby)"
46//usage: "\n -s,--seconds=SEC Set timeout in SEC seconds from now"
47//usage: "\n -t,--time=TIME Set timeout to TIME seconds from epoch"
48//usage: )
49//usage: IF_NOT_LONG_OPTS(
50//usage: "\n -a Read clock mode from adjtime"
51//usage: "\n -l Clock is set to local time"
52//usage: "\n -u Clock is set to UTC time"
53//usage: "\n -d DEV Specify the RTC device"
54//usage: "\n -m MODE Set sleep state (default: standby)"
55//usage: "\n -s SEC Set timeout in SEC seconds from now"
56//usage: "\n -t TIME Set timeout to TIME seconds from epoch"
57//usage: )
58
59#include "libbb.h"
60#include "rtc_.h"
61
62#define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup"
63#define SYS_POWER_PATH "/sys/power/state"
64
65static NOINLINE bool may_wakeup(const char *rtcname)
66{
67 ssize_t ret;
68 char buf[128];
69
70 /* strip "/dev/" from the rtcname here */
71 rtcname = skip_dev_pfx(rtcname);
72
73 snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
74 ret = open_read_close(buf, buf, sizeof(buf));
75 if (ret < 0)
76 return false;
77
78 /* wakeup events could be disabled or not supported */
79 return is_prefixed_with(buf, "enabled\n") != NULL;
80}
81
82static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
83{
84 struct tm *ptm;
85 struct linux_rtc_wkalrm wake;
86
87 /* The wakeup time is in POSIX time (more or less UTC).
88 * Ideally RTCs use that same time; but PCs can't do that
89 * if they need to boot MS-Windows. Messy...
90 *
91 * When running in utc mode this process's timezone is UTC,
92 * so we'll pass a UTC date to the RTC.
93 *
94 * Else mode is local so the time given to the RTC
95 * will instead use the local time zone.
96 */
97 ptm = localtime(wakeup);
98
99 wake.time.tm_sec = ptm->tm_sec;
100 wake.time.tm_min = ptm->tm_min;
101 wake.time.tm_hour = ptm->tm_hour;
102 wake.time.tm_mday = ptm->tm_mday;
103 wake.time.tm_mon = ptm->tm_mon;
104 wake.time.tm_year = ptm->tm_year;
105 /* wday, yday, and isdst fields are unused by Linux */
106 wake.time.tm_wday = -1;
107 wake.time.tm_yday = -1;
108 wake.time.tm_isdst = -1;
109
110 /* many rtc alarms only support up to 24 hours from 'now',
111 * so use the "more than 24 hours" request only if we must
112 */
113 if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
114 xioctl(fd, RTC_ALM_SET, &wake.time);
115 xioctl(fd, RTC_AIE_ON, 0);
116 } else {
117 /* avoid an extra AIE_ON call */
118 wake.enabled = 1;
119 xioctl(fd, RTC_WKALM_SET, &wake);
120 }
121}
122
123#define RTCWAKE_OPT_AUTO 0x01
124#define RTCWAKE_OPT_LOCAL 0x02
125#define RTCWAKE_OPT_UTC 0x04
126#define RTCWAKE_OPT_DEVICE 0x08
127#define RTCWAKE_OPT_SUSPEND_MODE 0x10
128#define RTCWAKE_OPT_SECONDS 0x20
129#define RTCWAKE_OPT_TIME 0x40
130
131int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
132int rtcwake_main(int argc UNUSED_PARAM, char **argv)
133{
134 unsigned opt;
135 const char *rtcname = NULL;
136 const char *suspend = "standby";
137 const char *opt_seconds;
138 const char *opt_time;
139
140 time_t rtc_time;
141 time_t sys_time;
142 time_t alarm_time = alarm_time;
143 unsigned seconds = seconds; /* for compiler */
144 int utc = -1;
145 int fd;
146
147#if ENABLE_LONG_OPTS
148 static const char rtcwake_longopts[] ALIGN1 =
149 "auto\0" No_argument "a"
150 "local\0" No_argument "l"
151 "utc\0" No_argument "u"
152 "device\0" Required_argument "d"
153 "mode\0" Required_argument "m"
154 "seconds\0" Required_argument "s"
155 "time\0" Required_argument "t"
156 ;
157 applet_long_options = rtcwake_longopts;
158#endif
159 /* Must have -s or -t, exclusive */
160 opt_complementary = "s:t:s--t:t--s";
161 opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time);
162
163 /* this is the default
164 if (opt & RTCWAKE_OPT_AUTO)
165 utc = -1;
166 */
167 if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
168 utc = opt & RTCWAKE_OPT_UTC;
169 if (opt & RTCWAKE_OPT_SECONDS) {
170 /* alarm time, seconds-to-sleep (relative) */
171 seconds = xatou(opt_seconds);
172 } else {
173 /* RTCWAKE_OPT_TIME */
174 /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
175 if (sizeof(alarm_time) <= sizeof(long))
176 alarm_time = xatol(opt_time);
177 else
178 alarm_time = xatoll(opt_time);
179 }
180
181 if (utc == -1)
182 utc = rtc_adjtime_is_utc();
183
184 /* the rtcname is relative to /dev */
185 xchdir("/dev");
186
187 /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
188 fd = rtc_xopen(&rtcname, O_RDONLY);
189
190 if (strcmp(suspend, "on") != 0)
191 if (!may_wakeup(rtcname))
192 bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
193
194 /* relative or absolute alarm time, normalized to time_t */
195 sys_time = time(NULL);
196 {
197 struct tm tm_time;
198 rtc_read_tm(&tm_time, fd);
199 rtc_time = rtc_tm2time(&tm_time, utc);
200 }
201
202 if (opt & RTCWAKE_OPT_TIME) {
203 /* Correct for RTC<->system clock difference */
204 alarm_time += rtc_time - sys_time;
205 if (alarm_time < rtc_time)
206 /*
207 * Compat message text.
208 * I'd say "RTC time is already ahead of ..." instead.
209 */
210 bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
211 } else
212 alarm_time = rtc_time + seconds + 1;
213
214 setup_alarm(fd, &alarm_time, rtc_time);
215 sync();
216#if 0 /*debug*/
217 printf("sys_time: %s", ctime(&sys_time));
218 printf("rtc_time: %s", ctime(&rtc_time));
219#endif
220 printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
221 fflush_all();
222 usleep(10 * 1000);
223
224 if (strcmp(suspend, "on") != 0)
225 xopen_xwrite_close(SYS_POWER_PATH, suspend);
226 else {
227 /* "fake" suspend ... we'll do the delay ourselves */
228 unsigned long data;
229
230 do {
231 ssize_t ret = safe_read(fd, &data, sizeof(data));
232 if (ret < 0) {
233 bb_perror_msg("rtc read");
234 break;
235 }
236 } while (!(data & RTC_AF));
237 }
238
239 xioctl(fd, RTC_AIE_OFF, 0);
240
241 if (ENABLE_FEATURE_CLEAN_UP)
242 close(fd);
243
244 return EXIT_SUCCESS;
245}
246
generated by cgit at 2024-05-15 00:43:40 (GMT)