1 | /*
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2 | * rtcwake -- enter a system sleep state until specified wakeup time.
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3 | *
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4 | * This version was taken from util-linux and scrubbed down for busybox.
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5 | *
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6 | * Licensed under GPLv2, see file LICENSE in this source tree.
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7 | *
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8 | * This uses cross-platform Linux interfaces to enter a system sleep state,
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9 | * and leave it no later than a specified time. It uses any RTC framework
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10 | * driver that supports standard driver model wakeup flags.
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11 | *
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12 | * This is normally used like the old "apmsleep" utility, to wake from a
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13 | * suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM). Most
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14 | * platforms can implement those without analogues of BIOS, APM, or ACPI.
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15 | *
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16 | * On some systems, this can also be used like "nvram-wakeup", waking
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17 | * from states like ACPI S4 (suspend to disk). Not all systems have
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18 | * persistent media that are appropriate for such suspend modes.
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19 | *
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20 | * The best way to set the system's RTC is so that it holds the current
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21 | * time in UTC. Use the "-l" flag to tell this program that the system
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22 | * RTC uses a local timezone instead (maybe you dual-boot MS-Windows).
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23 | * That flag should not be needed on systems with adjtime support.
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24 | */
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25 |
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26 | //usage:#define rtcwake_trivial_usage
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27 | //usage: "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
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28 | //usage:#define rtcwake_full_usage "\n\n"
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29 | //usage: "Enter a system sleep state until specified wakeup time\n"
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30 | //usage: IF_LONG_OPTS(
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31 | //usage: "\n -a,--auto Read clock mode from adjtime"
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32 | //usage: "\n -l,--local Clock is set to local time"
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33 | //usage: "\n -u,--utc Clock is set to UTC time"
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34 | //usage: "\n -d,--device=DEV Specify the RTC device"
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35 | //usage: "\n -m,--mode=MODE Set sleep state (default: standby)"
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36 | //usage: "\n -s,--seconds=SEC Set timeout in SEC seconds from now"
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37 | //usage: "\n -t,--time=TIME Set timeout to TIME seconds from epoch"
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38 | //usage: )
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39 | //usage: IF_NOT_LONG_OPTS(
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40 | //usage: "\n -a Read clock mode from adjtime"
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41 | //usage: "\n -l Clock is set to local time"
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42 | //usage: "\n -u Clock is set to UTC time"
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43 | //usage: "\n -d DEV Specify the RTC device"
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44 | //usage: "\n -m MODE Set sleep state (default: standby)"
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45 | //usage: "\n -s SEC Set timeout in SEC seconds from now"
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46 | //usage: "\n -t TIME Set timeout to TIME seconds from epoch"
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47 | //usage: )
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48 |
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49 | #include "libbb.h"
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50 | #include "rtc_.h"
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51 |
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52 | #define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup"
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53 | #define SYS_POWER_PATH "/sys/power/state"
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54 |
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55 | static NOINLINE bool may_wakeup(const char *rtcname)
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56 | {
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57 | ssize_t ret;
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58 | char buf[128];
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59 |
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60 | /* strip "/dev/" from the rtcname here */
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61 | rtcname = skip_dev_pfx(rtcname);
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62 |
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63 | snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
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64 | ret = open_read_close(buf, buf, sizeof(buf));
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65 | if (ret < 0)
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66 | return false;
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67 |
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68 | /* wakeup events could be disabled or not supported */
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69 | return is_prefixed_with(buf, "enabled\n") != NULL;
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70 | }
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71 |
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72 | static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
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73 | {
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74 | struct tm *ptm;
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75 | struct linux_rtc_wkalrm wake;
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76 |
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77 | /* The wakeup time is in POSIX time (more or less UTC).
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78 | * Ideally RTCs use that same time; but PCs can't do that
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79 | * if they need to boot MS-Windows. Messy...
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80 | *
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81 | * When running in utc mode this process's timezone is UTC,
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82 | * so we'll pass a UTC date to the RTC.
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83 | *
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84 | * Else mode is local so the time given to the RTC
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85 | * will instead use the local time zone.
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86 | */
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87 | ptm = localtime(wakeup);
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88 |
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89 | wake.time.tm_sec = ptm->tm_sec;
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90 | wake.time.tm_min = ptm->tm_min;
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91 | wake.time.tm_hour = ptm->tm_hour;
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92 | wake.time.tm_mday = ptm->tm_mday;
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93 | wake.time.tm_mon = ptm->tm_mon;
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94 | wake.time.tm_year = ptm->tm_year;
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95 | /* wday, yday, and isdst fields are unused by Linux */
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96 | wake.time.tm_wday = -1;
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97 | wake.time.tm_yday = -1;
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98 | wake.time.tm_isdst = -1;
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99 |
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100 | /* many rtc alarms only support up to 24 hours from 'now',
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101 | * so use the "more than 24 hours" request only if we must
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102 | */
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103 | if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
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104 | xioctl(fd, RTC_ALM_SET, &wake.time);
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105 | xioctl(fd, RTC_AIE_ON, 0);
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106 | } else {
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107 | /* avoid an extra AIE_ON call */
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108 | wake.enabled = 1;
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109 | xioctl(fd, RTC_WKALM_SET, &wake);
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110 | }
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111 | }
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112 |
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113 | #define RTCWAKE_OPT_AUTO 0x01
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114 | #define RTCWAKE_OPT_LOCAL 0x02
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115 | #define RTCWAKE_OPT_UTC 0x04
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116 | #define RTCWAKE_OPT_DEVICE 0x08
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117 | #define RTCWAKE_OPT_SUSPEND_MODE 0x10
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118 | #define RTCWAKE_OPT_SECONDS 0x20
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119 | #define RTCWAKE_OPT_TIME 0x40
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120 |
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121 | int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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122 | int rtcwake_main(int argc UNUSED_PARAM, char **argv)
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123 | {
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124 | unsigned opt;
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125 | const char *rtcname = NULL;
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126 | const char *suspend = "standby";
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127 | const char *opt_seconds;
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128 | const char *opt_time;
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129 |
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130 | time_t rtc_time;
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131 | time_t sys_time;
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132 | time_t alarm_time = alarm_time;
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133 | unsigned seconds = seconds; /* for compiler */
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134 | int utc = -1;
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135 | int fd;
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136 |
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137 | #if ENABLE_LONG_OPTS
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138 | static const char rtcwake_longopts[] ALIGN1 =
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139 | "auto\0" No_argument "a"
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140 | "local\0" No_argument "l"
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141 | "utc\0" No_argument "u"
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142 | "device\0" Required_argument "d"
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143 | "mode\0" Required_argument "m"
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144 | "seconds\0" Required_argument "s"
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145 | "time\0" Required_argument "t"
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146 | ;
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147 | applet_long_options = rtcwake_longopts;
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148 | #endif
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149 | /* Must have -s or -t, exclusive */
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150 | opt_complementary = "s:t:s--t:t--s";
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151 | opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time);
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152 |
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153 | /* this is the default
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154 | if (opt & RTCWAKE_OPT_AUTO)
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155 | utc = -1;
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156 | */
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157 | if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
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158 | utc = opt & RTCWAKE_OPT_UTC;
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159 | if (opt & RTCWAKE_OPT_SECONDS) {
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160 | /* alarm time, seconds-to-sleep (relative) */
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161 | seconds = xatou(opt_seconds);
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162 | } else {
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163 | /* RTCWAKE_OPT_TIME */
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164 | /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
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165 | if (sizeof(alarm_time) <= sizeof(long))
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166 | alarm_time = xatol(opt_time);
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167 | else
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168 | alarm_time = xatoll(opt_time);
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169 | }
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170 |
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171 | if (utc == -1)
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172 | utc = rtc_adjtime_is_utc();
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173 |
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174 | /* the rtcname is relative to /dev */
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175 | xchdir("/dev");
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176 |
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177 | /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
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178 | fd = rtc_xopen(&rtcname, O_RDONLY);
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179 |
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180 | if (strcmp(suspend, "on") != 0)
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181 | if (!may_wakeup(rtcname))
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182 | bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
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183 |
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184 | /* relative or absolute alarm time, normalized to time_t */
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185 | sys_time = time(NULL);
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186 | {
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187 | struct tm tm_time;
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188 | rtc_read_tm(&tm_time, fd);
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189 | rtc_time = rtc_tm2time(&tm_time, utc);
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190 | }
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191 |
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192 | if (opt & RTCWAKE_OPT_TIME) {
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193 | /* Correct for RTC<->system clock difference */
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194 | alarm_time += rtc_time - sys_time;
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195 | if (alarm_time < rtc_time)
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196 | /*
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197 | * Compat message text.
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198 | * I'd say "RTC time is already ahead of ..." instead.
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199 | */
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200 | bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
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201 | } else
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202 | alarm_time = rtc_time + seconds + 1;
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203 |
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204 | setup_alarm(fd, &alarm_time, rtc_time);
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205 | sync();
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206 | #if 0 /*debug*/
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207 | printf("sys_time: %s", ctime(&sys_time));
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208 | printf("rtc_time: %s", ctime(&rtc_time));
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209 | #endif
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210 | printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
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211 | fflush_all();
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212 | usleep(10 * 1000);
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213 |
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214 | if (strcmp(suspend, "on") != 0)
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215 | xopen_xwrite_close(SYS_POWER_PATH, suspend);
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216 | else {
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217 | /* "fake" suspend ... we'll do the delay ourselves */
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218 | unsigned long data;
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219 |
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220 | do {
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221 | ssize_t ret = safe_read(fd, &data, sizeof(data));
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222 | if (ret < 0) {
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223 | bb_perror_msg("rtc read");
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224 | break;
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225 | }
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226 | } while (!(data & RTC_AF));
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227 | }
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228 |
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229 | xioctl(fd, RTC_AIE_OFF, 0);
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230 |
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231 | if (ENABLE_FEATURE_CLEAN_UP)
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232 | close(fd);
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233 |
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234 | return EXIT_SUCCESS;
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235 | }
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