diff options
Diffstat (limited to 'rtc.c')
| -rw-r--r-- | rtc.c | 242 |
1 files changed, 242 insertions, 0 deletions
@@ -0,0 +1,242 @@ +/* + chronyd/chronyc - Programs for keeping computer clocks accurate. + + ********************************************************************** + * Copyright (C) Richard P. Curnow 1997-2003 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + ********************************************************************** + + ======================================================================= + + */ + +#include "config.h" + +#include "sysincl.h" + +#include "rtc.h" +#include "local.h" +#include "logging.h" +#include "conf.h" + +#if defined LINUX && defined FEAT_RTC +#include "rtc_linux.h" +#endif /* defined LINUX */ + +/* ================================================== */ + +static int driver_initialised = 0; +static int driver_preinit_ok = 0; + +static struct { + int (*init)(void); + void (*fini)(void); + int (*time_pre_init)(time_t driftfile_time); + void (*time_init)(void (*after_hook)(void*), void *anything); + void (*start_measurements)(void); + int (*write_parameters)(void); + int (*get_report)(RPT_RTC_Report *report); + int (*trim)(void); +} driver = +{ +#if defined LINUX && defined FEAT_RTC + RTC_Linux_Initialise, + RTC_Linux_Finalise, + RTC_Linux_TimePreInit, + RTC_Linux_TimeInit, + RTC_Linux_StartMeasurements, + RTC_Linux_WriteParameters, + RTC_Linux_GetReport, + RTC_Linux_Trim +#else + NULL, + NULL, + NULL, + NULL, + NULL, + NULL, + NULL, + NULL +#endif +}; + +/* ================================================== */ +/* Get the last modification time of the driftfile */ + +static time_t +get_driftfile_time(void) +{ + struct stat buf; + char *drift_file; + + drift_file = CNF_GetDriftFile(); + if (!drift_file) + return 0; + + if (stat(drift_file, &buf)) + return 0; + + return buf.st_mtime; +} + +/* ================================================== */ +/* Set the system time to the driftfile time if it's in the future */ + +static void +apply_driftfile_time(time_t t) +{ + struct timespec now; + + LCL_ReadCookedTime(&now, NULL); + + if (now.tv_sec < t) { + if (LCL_ApplyStepOffset(now.tv_sec - t)) + LOG(LOGS_INFO, "System time restored from driftfile"); + } +} + +/* ================================================== */ + +void +RTC_Initialise(int initial_set) +{ + time_t driftfile_time; + char *file_name; + + /* If the -s option was specified, try to do an initial read of the RTC and + set the system time to it. Also, read the last modification time of the + driftfile (i.e. system time when chronyd was previously stopped) and set + the system time to it if it's in the future to bring the clock closer to + the true time when the RTC is broken (e.g. it has no battery), is missing, + or there is no RTC driver. */ + if (initial_set) { + driftfile_time = get_driftfile_time(); + + if (driver.time_pre_init && driver.time_pre_init(driftfile_time)) { + driver_preinit_ok = 1; + } else { + driver_preinit_ok = 0; + if (driftfile_time) + apply_driftfile_time(driftfile_time); + } + } + + driver_initialised = 0; + + /* This is how we tell whether the user wants to load the RTC + driver, if he is on a machine where it is an option. */ + file_name = CNF_GetRtcFile(); + + if (file_name) { + if (CNF_GetRtcSync()) { + LOG_FATAL("rtcfile directive cannot be used with rtcsync"); + } + + if (driver.init) { + if ((driver.init)()) { + driver_initialised = 1; + } else { + LOG(LOGS_ERR, "RTC driver could not be initialised"); + } + } else { + LOG(LOGS_ERR, "RTC not supported on this operating system"); + } + } +} + +/* ================================================== */ + +void +RTC_Finalise(void) +{ + if (driver_initialised) { + (driver.fini)(); + } +} + +/* ================================================== */ +/* Start the processing to get a single measurement from the real time + clock, and use it to trim the system time, based on knowing the + drift rate of the RTC and the error the last time we set it. If the + TimePreInit routine has succeeded, we can be sure that the trim required + is not *too* large. + + We are called with a hook to a function to be called after the + initialisation is complete. We also call this if we cannot do the + initialisation. */ + +void +RTC_TimeInit(void (*after_hook)(void *), void *anything) +{ + if (driver_initialised && driver_preinit_ok) { + (driver.time_init)(after_hook, anything); + } else { + (after_hook)(anything); + } +} + +/* ================================================== */ +/* Start the RTC measurement process */ + +void +RTC_StartMeasurements(void) +{ + if (driver_initialised) { + (driver.start_measurements)(); + } + /* Benign if driver not present */ +} + +/* ================================================== */ +/* Write RTC information out to RTC file. Return 0 for success, 1 if + RTC driver not running, or 2 if the file cannot be written. */ + +int +RTC_WriteParameters(void) +{ + if (driver_initialised) { + return (driver.write_parameters)(); + } else { + return RTC_ST_NODRV; + } +} + +/* ================================================== */ + +int +RTC_GetReport(RPT_RTC_Report *report) +{ + if (driver_initialised) { + return (driver.get_report)(report); + } else { + return 0; + } +} + +/* ================================================== */ + +int +RTC_Trim(void) +{ + if (driver_initialised) { + return (driver.trim)(); + } else { + return 0; + } +} + +/* ================================================== */ + |