diff options
Diffstat (limited to 'toys/pending/hwclock.c')
| -rw-r--r-- | toys/pending/hwclock.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/toys/pending/hwclock.c b/toys/pending/hwclock.c new file mode 100644 index 00000000..980d1651 --- /dev/null +++ b/toys/pending/hwclock.c @@ -0,0 +1,160 @@ +/* hwclock.c - get and set the hwclock + * + * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com> + * + * No Standard. + * +USE_HWCLOCK(NEWTOY(hwclock, "f(rtc):u(utc)l(localtime)t(systz)w(systohc)s(hctosys)r(show)[!ul][!rs][!rw][!rt][!sw][!st][!wt]", TOYFLAG_USR|TOYFLAG_BIN)) + +config HWCLOCK + bool "hwclock" + default n + help + usage: hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-t|--systz] [-l|--localtime] + [-u|--utc] [-f|--rtc FILE] + + -f FILE Use specified device file (e.g. /dev/rtc2) instead of default + -l Assume hardware clock is kept in localtime + -r Show hardware clock time + -s Set system time from hardware clock + -t Set the system time based on the current timezone + -u Assume hardware clock is kept in UTC + -w Set hardware clock from system time +*/ +#define FOR_hwclock +#include "toys.h" +#include <linux/rtc.h> + +GLOBALS( + char *fname; + + int utc; +) + +static int rtc_open(char **dev_rtc, int flag) +{ + if (!*dev_rtc) { + int fd; + + if ((fd = open((*dev_rtc = "/dev/rtc"), flag)) != -1) return fd; + else if ((fd = open((*dev_rtc = "/dev/rtc0"), flag)) != -1) return fd; + else *dev_rtc = "/dev/misc/rtc"; + } + return xopen(*dev_rtc, flag); +} + +static time_t get_rtc() +{ + struct tm time; + time_t tm; + char *ptz_old = NULL; + int fd = rtc_open(&TT.fname, O_RDONLY); + + memset(&time, 0, sizeof(time)); + xioctl(fd, RTC_RD_TIME, &time); + close(fd); + if (TT.utc) { + ptz_old = getenv("TZ"); + if (putenv((char*)"TZ=UTC0")) perror_exit("putenv"); + tzset(); + } + if ((tm = mktime(&time)) < 0) error_exit("mktime failed"); + if (TT.utc) { + if (unsetenv("TZ") < 0) perror_exit("unsetenv"); + if (ptz_old && putenv(ptz_old - 3)) perror_exit("putenv"); + tzset(); + } + return tm; +} + +static void set_sysclock_from_hwclock() +{ + struct timezone tmzone; + struct timeval tmval; + + tmzone.tz_minuteswest = timezone / 60 - 60 * daylight; + tmzone.tz_dsttime = 0; + tmval.tv_sec = get_rtc(); + tmval.tv_usec = 0; + if (settimeofday(&tmval, &tmzone) < 0) perror_exit("settimeofday"); +} + +static void set_hwclock_from_sysclock() +{ + struct timeval tmval; + struct tm time; + int fd = rtc_open(&TT.fname, O_WRONLY); + + if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday"); + // converting a time value to broken-down UTC time + if (TT. utc && !gmtime_r((time_t*)&tmval.tv_sec, &time)) + error_exit("gmtime_r failed"); + // converting a time value to a broken-down localtime + else if (!(localtime_r((time_t*)&tmval.tv_sec, &time))) + error_exit("localtime_r failed"); + + /* The value of tm_isdst will positive if daylight saving time is in effect, + * zero if it is not and negative if the information is not available. + * */ + time.tm_isdst = 0; + xioctl(fd, RTC_SET_TIME, &time); + close(fd); +} + +static void set_sysclock_timezone() +{ + struct timezone tmzone; + struct timeval tmval; + struct tm *pb; + + if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday"); + if (!(pb = localtime(&tmval.tv_sec))) error_exit("localtime failed"); + // extern long timezone => defined in header sys/time.h + tmzone.tz_minuteswest = timezone / 60; + if (pb->tm_isdst) tmzone.tz_minuteswest -= 60; + tmzone.tz_dsttime = 0; // daylight saving time is not in effect + if (gettimeofday(&tmval, NULL) < 0) perror_exit("gettimeofday"); + if (!TT.utc) tmval.tv_sec += tmzone.tz_minuteswest * 60; + if (settimeofday(&tmval, &tmzone) < 0) perror_exit("settimeofday"); +} + +static void rtc_adjtime() +{ + char *line = NULL; + int fd = open("/etc/adjtime", O_RDONLY); + + if (fd != -1) { + for (; (line = get_line(fd)); free(line)) { + if (!strncmp(line, "UTC", 3)) { + TT.utc = 1; + break; + } + } + close(fd); + } +} + +static void display_hwclock() +{ + time_t tm = get_rtc(); + char *s, *pctm = ctime(&tm); + + if (pctm) { + if ((s = strrchr(pctm, '\n'))) *s = '\0'; + xprintf("%s 0.000000 seconds\n", pctm); + } else error_exit("failed to convert a time value to a date & time string"); +} + +void hwclock_main() +{ + (!(toys.optflags & FLAG_u)) ? rtc_adjtime() : (TT.utc = 1); // check for UTC + if (toys.optflags & FLAG_w) set_hwclock_from_sysclock(); + else if (toys.optflags & FLAG_s) set_sysclock_from_hwclock(); + else if (toys.optflags & FLAG_t) set_sysclock_timezone(); + else if ((toys.optflags & FLAG_r) || (toys.optflags & FLAG_l) + || !*toys.optargs) display_hwclock(); + else { + toys.exithelp++; + error_exit("invalid option '%s'", *toys.optargs); + } +} |