blob: 735a298223c5277e19114d0bedbdd7d82f699065
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 | |
56 | static 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 | |
73 | static 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 | |
122 | int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
123 | int 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 | } |
227 |