diff options
Diffstat (limited to 'util-linux/hwclock.c')
-rw-r--r-- | util-linux/hwclock.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/util-linux/hwclock.c b/util-linux/hwclock.c new file mode 100644 index 000000000..8fcd8c99c --- /dev/null +++ b/util-linux/hwclock.c @@ -0,0 +1,213 @@ +/* vi: set sw=4 ts=4: */ +/* + * Mini hwclock implementation for busybox + * + * Copyright (C) 2002 Robert Griebl <griebl@gmx.de> + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. +*/ + + +#include <sys/ioctl.h> +#include <sys/utsname.h> +#include <getopt.h> +#include "busybox.h" + +/* Copied from linux/rtc.h to eliminate the kernel dependency */ +struct linux_rtc_time { + int tm_sec; + int tm_min; + int tm_hour; + int tm_mday; + int tm_mon; + int tm_year; + int tm_wday; + int tm_yday; + int tm_isdst; +}; + +#define RTC_SET_TIME _IOW('p', 0x0a, struct linux_rtc_time) /* Set RTC time */ +#define RTC_RD_TIME _IOR('p', 0x09, struct linux_rtc_time) /* Read RTC time */ + +#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS +# ifndef _GNU_SOURCE +# define _GNU_SOURCE +# endif +#endif + +static int xopen_rtc(int flags) +{ + int rtc; + rtc = open("/dev/rtc", flags); + if (rtc < 0) { + rtc = open("/dev/misc/rtc", flags); + if (rtc < 0) + bb_perror_msg_and_die("cannot access RTC"); + } + return rtc; +} + +static time_t read_rtc(int utc) +{ + struct tm tm; + char *oldtz = 0; + time_t t = 0; + int rtc = xopen_rtc(O_RDONLY); + + memset(&tm, 0, sizeof(struct tm)); + if (ioctl(rtc, RTC_RD_TIME, &tm) < 0 ) + bb_perror_msg_and_die("cannot read time from RTC"); + tm.tm_isdst = -1; /* not known */ + + close(rtc); + + if (utc) { + oldtz = getenv("TZ"); + setenv("TZ", "UTC 0", 1); + tzset(); + } + + t = mktime(&tm); + + if (utc) { + if (oldtz) + setenv("TZ", oldtz, 1); + else + unsetenv("TZ"); + tzset(); + } + return t; +} + +static void write_rtc(time_t t, int utc) +{ + struct tm tm; + int rtc = xopen_rtc(O_WRONLY); + + tm = *(utc ? gmtime(&t) : localtime(&t)); + tm.tm_isdst = 0; + + if (ioctl(rtc, RTC_SET_TIME, &tm) < 0) + bb_perror_msg_and_die("cannot set the RTC time"); + + close(rtc); +} + +static int show_clock(int utc) +{ + struct tm *ptm; + time_t t; + RESERVE_CONFIG_BUFFER(buffer, 64); + + t = read_rtc(utc); + ptm = localtime(&t); /* Sets 'tzname[]' */ + + safe_strncpy(buffer, ctime(&t), 64); + if (buffer[0]) + buffer[strlen(buffer) - 1] = 0; + + //printf("%s %.6f seconds %s\n", buffer, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0])); + printf( "%s %.6f seconds\n", buffer, 0.0); + RELEASE_CONFIG_BUFFER(buffer); + + return 0; +} + +static int to_sys_clock(int utc) +{ + struct timeval tv = { 0, 0 }; + const struct timezone tz = { timezone/60 - 60*daylight, 0 }; + + tv.tv_sec = read_rtc(utc); + + if (settimeofday(&tv, &tz)) + bb_perror_msg_and_die("settimeofday() failed"); + + return 0; +} + +static int from_sys_clock(int utc) +{ + struct timeval tv = { 0, 0 }; + struct timezone tz = { 0, 0 }; + + if (gettimeofday(&tv, &tz)) + bb_perror_msg_and_die("gettimeofday() failed"); + + write_rtc(tv.tv_sec, utc); + return 0; +} + +#ifdef CONFIG_FEATURE_HWCLOCK_ADJTIME_FHS +# define ADJTIME_PATH "/var/lib/hwclock/adjtime" +#else +# define ADJTIME_PATH "/etc/adjtime" +#endif +static int check_utc(void) +{ + int utc = 0; + FILE *f = fopen(ADJTIME_PATH, "r"); + + if (f) { + RESERVE_CONFIG_BUFFER(buffer, 128); + + while (fgets(buffer, sizeof(buffer), f)) { + int len = strlen(buffer); + + while (len && isspace(buffer[len - 1])) + len--; + + buffer[len] = 0; + + if (strncmp(buffer, "UTC", 3) == 0 ) { + utc = 1; + break; + } + } + fclose(f); + RELEASE_CONFIG_BUFFER(buffer); + } + return utc; +} + +#define HWCLOCK_OPT_LOCALTIME 0x01 +#define HWCLOCK_OPT_UTC 0x02 +#define HWCLOCK_OPT_SHOW 0x04 +#define HWCLOCK_OPT_HCTOSYS 0x08 +#define HWCLOCK_OPT_SYSTOHC 0x10 + +int hwclock_main(int argc, char **argv ) +{ + unsigned opt; + int utc; + +#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS + static const struct option hwclock_long_options[] = { + { "localtime", 0, 0, 'l' }, + { "utc", 0, 0, 'u' }, + { "show", 0, 0, 'r' }, + { "hctosys", 0, 0, 's' }, + { "systohc", 0, 0, 'w' }, + { 0, 0, 0, 0 } + }; + applet_long_options = hwclock_long_options; +#endif + opt_complementary = "?:r--ws:w--rs:s--wr:l--u:u--l"; + opt = getopt32(argc, argv, "lursw"); + + /* If -u or -l wasn't given check if we are using utc */ + if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME)) + utc = opt & HWCLOCK_OPT_UTC; + else + utc = check_utc(); + + if (opt & HWCLOCK_OPT_HCTOSYS) { + return to_sys_clock(utc); + } + else if (opt & HWCLOCK_OPT_SYSTOHC) { + return from_sys_clock(utc); + } else { + /* default HWCLOCK_OPT_SHOW */ + return show_clock(utc); + } +} |