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