1/* hwclock.c - get and set the hwclock 2 * 3 * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com> 4 * 5 * No standard, but see Documentation/rtc.txt in the linux kernel source.. 6 * 7USE_HWCLOCK(NEWTOY(hwclock, ">0(fast)f(rtc):u(utc)l(localtime)t(systz)s(hctosys)r(show)w(systohc)[-ul][!rtsw]", TOYFLAG_SBIN)) 8 9config HWCLOCK 10 bool "hwclock" 11 default y 12 help 13 usage: hwclock [-rswtluf] 14 15 Get/set the hardware clock. 16 17 -f FILE Use specified device file instead of /dev/rtc (--rtc) 18 -l Hardware clock uses localtime (--localtime) 19 -r Show hardware clock time (--show) 20 -s Set system time from hardware clock (--hctosys) 21 -t Set the system time based on the current timezone (--systz) 22 -u Hardware clock uses UTC (--utc) 23 -w Set hardware clock from system time (--systohc) 24*/ 25 26#define FOR_hwclock 27#include "toys.h" 28#include <linux/rtc.h> 29 30GLOBALS( 31 char *f; 32 33 int utc; 34) 35 36static int rtc_find(struct dirtree* node) 37{ 38 FILE *fp; 39 40 if (!node->parent) return DIRTREE_RECURSE; 41 42 sprintf(toybuf, "/sys/class/rtc/%s/hctosys", node->name); 43 fp = fopen(toybuf, "r"); 44 if (fp) { 45 int hctosys = 0, items = fscanf(fp, "%d", &hctosys); 46 47 fclose(fp); 48 if (items == 1 && hctosys == 1) { 49 sprintf(toybuf, "/dev/%s", node->name); 50 TT.f = toybuf; 51 52 return DIRTREE_ABORT; 53 } 54 } 55 56 return 0; 57} 58 59void hwclock_main() 60{ 61 struct timezone tzone; 62 struct timeval timeval; 63 struct tm tm; 64 time_t time; 65 int fd = -1; 66 67 // check for Grenich Mean Time 68 if (toys.optflags & FLAG_u) TT.utc = 1; 69 else { 70 FILE *fp; 71 char *s = 0; 72 73 for (fp = fopen("/etc/adjtime", "r"); 74 fp && getline(&s, (void *)toybuf, fp)>0; 75 free(s), s = 0) TT.utc += !strncmp(s, "UTC", 3); 76 if (fp) fclose(fp); 77 } 78 79 if (!(toys.optflags&FLAG_t)) { 80 int w = toys.optflags & FLAG_w, flag = O_WRONLY*w; 81 82 // Open /dev/rtc (if your system has no /dev/rtc symlink, search for it). 83 if (!TT.f && (fd = open("/dev/rtc", flag)) == -1) { 84 dirtree_read("/sys/class/rtc", rtc_find); 85 if (!TT.f) TT.f = "/dev/misc/rtc"; 86 } 87 if (fd == -1) fd = xopen(TT.f, flag); 88 89 // Get current time in seconds from rtc device. todo: get subsecond time 90 if (!w) { 91 char *s = s; 92 93 xioctl(fd, RTC_RD_TIME, &tm); 94 if (TT.utc) s = xtzset("UTC0"); 95 if ((time = mktime(&tm)) < 0) error_exit("mktime failed"); 96 if (TT.utc) { 97 free(xtzset(s)); 98 free(s); 99 } 100 } 101 } 102 103 if (toys.optflags & (FLAG_w|FLAG_t)) { 104 if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed"); 105 if (!(TT.utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm)) 106 error_exit(TT.utc ? "gmtime_r failed" : "localtime_r failed"); 107 } 108 109 if (toys.optflags & FLAG_w) { 110 /* The value of tm_isdst is positive if daylight saving time is in effect, 111 * zero if it is not and negative if the information is not available. 112 * todo: so why isn't this negative...? */ 113 tm.tm_isdst = 0; 114 xioctl(fd, RTC_SET_TIME, &tm); 115 } else if (toys.optflags & FLAG_s) { 116 tzone.tz_minuteswest = timezone / 60 - 60 * daylight; 117 timeval.tv_sec = time; 118 timeval.tv_usec = 0; // todo: fixit 119 } else if (toys.optflags & FLAG_t) { 120 // Adjust seconds for timezone and daylight saving time 121 // extern long timezone is defined in header sys/time.h 122 tzone.tz_minuteswest = timezone / 60; 123 if (tm.tm_isdst) tzone.tz_minuteswest -= 60; 124 if (!TT.utc) timeval.tv_sec += tzone.tz_minuteswest * 60; 125 } else { 126 char *c = ctime(&time), *s = strrchr(c, '\n'); 127 128 if (s) *s = '\0'; 129 // TODO: implement this. 130 xprintf("%s 0.000000 seconds\n", c); 131 } 132 if (toys.optflags & (FLAG_t|FLAG_s)) { 133 tzone.tz_dsttime = 0; 134 if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed"); 135 } 136 137 if (fd != -1) close(fd); 138} 139