Contents of /tags/mkinitrd-6_5_0/busybox/util-linux/rtcwake.c
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Fri Jun 3 21:22:00 2011 UTC (13 years, 3 months ago) by niro
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Fri Jun 3 21:22:00 2011 UTC (13 years, 3 months ago) by niro
File MIME type: text/plain
File size: 5818 byte(s)
tagged 'mkinitrd-6_5_0'
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 tarball for details. |
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 | #include "libbb.h" |
27 | #include "rtc_.h" |
28 | |
29 | #define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup" |
30 | #define SYS_POWER_PATH "/sys/power/state" |
31 | #define DEFAULT_MODE "standby" |
32 | |
33 | static NOINLINE bool may_wakeup(const char *rtcname) |
34 | { |
35 | ssize_t ret; |
36 | char buf[128]; |
37 | |
38 | /* strip "/dev/" from the rtcname here */ |
39 | rtcname = skip_dev_pfx(rtcname); |
40 | |
41 | snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname); |
42 | ret = open_read_close(buf, buf, sizeof(buf)); |
43 | if (ret < 0) |
44 | return false; |
45 | |
46 | /* wakeup events could be disabled or not supported */ |
47 | return strncmp(buf, "enabled\n", 8) == 0; |
48 | } |
49 | |
50 | static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time) |
51 | { |
52 | struct tm *ptm; |
53 | struct linux_rtc_wkalrm wake; |
54 | |
55 | /* The wakeup time is in POSIX time (more or less UTC). |
56 | * Ideally RTCs use that same time; but PCs can't do that |
57 | * if they need to boot MS-Windows. Messy... |
58 | * |
59 | * When running in utc mode this process's timezone is UTC, |
60 | * so we'll pass a UTC date to the RTC. |
61 | * |
62 | * Else mode is local so the time given to the RTC |
63 | * will instead use the local time zone. |
64 | */ |
65 | ptm = localtime(wakeup); |
66 | |
67 | wake.time.tm_sec = ptm->tm_sec; |
68 | wake.time.tm_min = ptm->tm_min; |
69 | wake.time.tm_hour = ptm->tm_hour; |
70 | wake.time.tm_mday = ptm->tm_mday; |
71 | wake.time.tm_mon = ptm->tm_mon; |
72 | wake.time.tm_year = ptm->tm_year; |
73 | /* wday, yday, and isdst fields are unused by Linux */ |
74 | wake.time.tm_wday = -1; |
75 | wake.time.tm_yday = -1; |
76 | wake.time.tm_isdst = -1; |
77 | |
78 | /* many rtc alarms only support up to 24 hours from 'now', |
79 | * so use the "more than 24 hours" request only if we must |
80 | */ |
81 | if ((rtc_time + (24 * 60 * 60)) > *wakeup) { |
82 | xioctl(fd, RTC_ALM_SET, &wake.time); |
83 | xioctl(fd, RTC_AIE_ON, 0); |
84 | } else { |
85 | /* avoid an extra AIE_ON call */ |
86 | wake.enabled = 1; |
87 | xioctl(fd, RTC_WKALM_SET, &wake); |
88 | } |
89 | } |
90 | |
91 | #define RTCWAKE_OPT_AUTO 0x01 |
92 | #define RTCWAKE_OPT_LOCAL 0x02 |
93 | #define RTCWAKE_OPT_UTC 0x04 |
94 | #define RTCWAKE_OPT_DEVICE 0x08 |
95 | #define RTCWAKE_OPT_SUSPEND_MODE 0x10 |
96 | #define RTCWAKE_OPT_SECONDS 0x20 |
97 | #define RTCWAKE_OPT_TIME 0x40 |
98 | |
99 | int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
100 | int rtcwake_main(int argc UNUSED_PARAM, char **argv) |
101 | { |
102 | time_t rtc_time; |
103 | |
104 | unsigned opt; |
105 | const char *rtcname = NULL; |
106 | const char *suspend; |
107 | const char *opt_seconds; |
108 | const char *opt_time; |
109 | |
110 | time_t sys_time; |
111 | time_t alarm_time = 0; |
112 | unsigned seconds = 0; |
113 | int utc = -1; |
114 | int fd; |
115 | |
116 | #if ENABLE_LONG_OPTS |
117 | static const char rtcwake_longopts[] ALIGN1 = |
118 | "auto\0" No_argument "a" |
119 | "local\0" No_argument "l" |
120 | "utc\0" No_argument "u" |
121 | "device\0" Required_argument "d" |
122 | "mode\0" Required_argument "m" |
123 | "seconds\0" Required_argument "s" |
124 | "time\0" Required_argument "t" |
125 | ; |
126 | applet_long_options = rtcwake_longopts; |
127 | #endif |
128 | opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time); |
129 | |
130 | /* this is the default |
131 | if (opt & RTCWAKE_OPT_AUTO) |
132 | utc = -1; |
133 | */ |
134 | if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL)) |
135 | utc = opt & RTCWAKE_OPT_UTC; |
136 | if (!(opt & RTCWAKE_OPT_SUSPEND_MODE)) |
137 | suspend = DEFAULT_MODE; |
138 | if (opt & RTCWAKE_OPT_SECONDS) |
139 | /* alarm time, seconds-to-sleep (relative) */ |
140 | seconds = xatoi(opt_seconds); |
141 | if (opt & RTCWAKE_OPT_TIME) |
142 | /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */ |
143 | alarm_time = xatol(opt_time); |
144 | |
145 | if (!alarm_time && !seconds) |
146 | bb_error_msg_and_die("must provide wake time"); |
147 | |
148 | if (utc == -1) |
149 | utc = rtc_adjtime_is_utc(); |
150 | |
151 | /* the rtcname is relative to /dev */ |
152 | xchdir("/dev"); |
153 | |
154 | /* this RTC must exist and (if we'll sleep) be wakeup-enabled */ |
155 | fd = rtc_xopen(&rtcname, O_RDONLY); |
156 | |
157 | if (strcmp(suspend, "on") && !may_wakeup(rtcname)) |
158 | bb_error_msg_and_die("%s not enabled for wakeup events", rtcname); |
159 | |
160 | /* relative or absolute alarm time, normalized to time_t */ |
161 | sys_time = time(NULL); |
162 | { |
163 | struct tm tm_time; |
164 | rtc_read_tm(&tm_time, fd); |
165 | rtc_time = rtc_tm2time(&tm_time, utc); |
166 | } |
167 | |
168 | |
169 | if (alarm_time) { |
170 | if (alarm_time < sys_time) |
171 | bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time)); |
172 | alarm_time += sys_time - rtc_time; |
173 | } else |
174 | alarm_time = rtc_time + seconds + 1; |
175 | setup_alarm(fd, &alarm_time, rtc_time); |
176 | |
177 | sync(); |
178 | printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time)); |
179 | fflush_all(); |
180 | usleep(10 * 1000); |
181 | |
182 | if (strcmp(suspend, "on")) |
183 | xopen_xwrite_close(SYS_POWER_PATH, suspend); |
184 | else { |
185 | /* "fake" suspend ... we'll do the delay ourselves */ |
186 | unsigned long data; |
187 | |
188 | do { |
189 | ssize_t ret = safe_read(fd, &data, sizeof(data)); |
190 | if (ret < 0) { |
191 | bb_perror_msg("rtc read"); |
192 | break; |
193 | } |
194 | } while (!(data & RTC_AF)); |
195 | } |
196 | |
197 | xioctl(fd, RTC_AIE_OFF, 0); |
198 | |
199 | if (ENABLE_FEATURE_CLEAN_UP) |
200 | close(fd); |
201 | |
202 | return EXIT_SUCCESS; |
203 | } |