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/*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* rtc.c - Use /dev/rtc for clock access
*/
#include <asm/ioctl.h>
#include <errno.h>
#include <linux/rtc.h>
#include <linux/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "monotonic.h"
#include "strutils.h"
#include "xalloc.h"
#include "nls.h"
#include "hwclock.h"
#ifndef RTC_PARAM_GET
struct rtc_param {
__u64 param;
union {
__u64 uvalue;
__s64 svalue;
__u64 ptr;
};
__u32 index;
__u32 __pad;
};
# define RTC_PARAM_GET _IOW('p', 0x13, struct rtc_param)
# define RTC_PARAM_SET _IOW('p', 0x14, struct rtc_param)
# define RTC_PARAM_FEATURES 0
# define RTC_PARAM_CORRECTION 1
# define RTC_PARAM_BACKUP_SWITCH_MODE 2
#endif /* RTC_PARAM_GET */
static const struct hwclock_param hwclock_params[] =
{
{ RTC_PARAM_FEATURES, "features", N_("supported features") },
{ RTC_PARAM_CORRECTION, "correction", N_("time correction") },
{ RTC_PARAM_BACKUP_SWITCH_MODE, "bsm", N_("backup switch mode") },
{ }
};
const struct hwclock_param *get_hwclock_params(void)
{
return hwclock_params;
}
/*
* /dev/rtc is conventionally chardev 10/135
* ia64 uses /dev/efirtc, chardev 10/136
* devfs (obsolete) used /dev/misc/... for miscdev
* new RTC framework + udev uses dynamic major and /dev/rtc0.../dev/rtcN
* ... so we need an overridable default
*/
/* default or user defined dev (by hwclock --rtc=<path>) */
static const char *rtc_dev_name;
static int rtc_dev_fd = -1;
static void close_rtc(void)
{
if (rtc_dev_fd != -1)
close(rtc_dev_fd);
rtc_dev_fd = -1;
}
static int open_rtc(const struct hwclock_control *ctl)
{
static const char * const fls[] = {
#ifdef __ia64__
"/dev/efirtc",
"/dev/misc/efirtc",
#endif
"/dev/rtc0",
"/dev/rtc",
"/dev/misc/rtc"
};
size_t i;
if (rtc_dev_fd != -1)
return rtc_dev_fd;
/* --rtc option has been given */
if (ctl->rtc_dev_name) {
rtc_dev_name = ctl->rtc_dev_name;
rtc_dev_fd = open(rtc_dev_name, O_RDONLY);
} else {
for (i = 0; i < ARRAY_SIZE(fls); i++) {
if (ctl->verbose)
printf(_("Trying to open: %s\n"), fls[i]);
rtc_dev_fd = open(fls[i], O_RDONLY);
if (rtc_dev_fd < 0) {
if (errno == ENOENT || errno == ENODEV)
continue;
if (ctl->verbose)
warn(_("cannot open %s"), fls[i]);
}
rtc_dev_name = fls[i];
break;
}
if (rtc_dev_fd < 0)
rtc_dev_name = *fls; /* default for error messages */
}
if (rtc_dev_fd != -1)
atexit(close_rtc);
return rtc_dev_fd;
}
static int open_rtc_or_exit(const struct hwclock_control *ctl)
{
int rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open rtc device"));
hwclock_exit(ctl, EXIT_FAILURE);
}
return rtc_fd;
}
static int do_rtc_read_ioctl(int rtc_fd, struct tm *tm)
{
int rc = -1;
struct rtc_time rtc_tm = { 0 };
rc = ioctl(rtc_fd, RTC_RD_TIME, &rtc_tm);
if (rc == -1) {
warn(_("ioctl(RTC_RD_NAME) to %s to read the time failed"),
rtc_dev_name);
return -1;
}
/* kernel uses private struct tm definition to be self contained */
tm->tm_sec = rtc_tm.tm_sec;
tm->tm_min = rtc_tm.tm_min;
tm->tm_hour = rtc_tm.tm_hour;
tm->tm_mday = rtc_tm.tm_mday;
tm->tm_mon = rtc_tm.tm_mon;
tm->tm_year = rtc_tm.tm_year;
tm->tm_wday = rtc_tm.tm_wday;
tm->tm_yday = rtc_tm.tm_yday;
tm->tm_isdst = -1; /* don't know whether it's dst */
return 0;
}
/*
* Wait for the top of a clock tick by reading /dev/rtc in a busy loop
* until we see it. This function is used for rtc drivers without ioctl
* interrupts. This is typical on an Alpha, where the Hardware Clock
* interrupts are used by the kernel for the system clock, so aren't at
* the user's disposal.
*/
static int busywait_for_rtc_clock_tick(const struct hwclock_control *ctl,
const int rtc_fd)
{
struct tm start_time = { 0 };
/* The time when we were called (and started waiting) */
struct tm nowtime = { 0 };
int rc;
struct timeval begin = { 0 }, now = { 0 };
if (ctl->verbose) {
printf("ioctl(%d, RTC_UIE_ON, 0): %s\n",
rtc_fd, strerror(errno));
printf(_("Waiting in loop for time from %s to change\n"),
rtc_dev_name);
}
if (do_rtc_read_ioctl(rtc_fd, &start_time))
return 1;
/*
* Wait for change. Should be within a second, but in case
* something weird happens, we have a time limit (1.5s) on this loop
* to reduce the impact of this failure.
*/
gettime_monotonic(&begin);
do {
rc = do_rtc_read_ioctl(rtc_fd, &nowtime);
if (rc || start_time.tm_sec != nowtime.tm_sec)
break;
gettime_monotonic(&now);
if (time_diff(now, begin) > 1.5) {
warnx(_("Timed out waiting for time change."));
return 1;
}
} while (1);
if (rc)
return 1;
return 0;
}
/*
* Same as synchronize_to_clock_tick(), but just for /dev/rtc.
*/
static int synchronize_to_clock_tick_rtc(const struct hwclock_control *ctl)
{
int rtc_fd; /* File descriptor of /dev/rtc */
int ret = 1;
rtc_fd = open_rtc(ctl);
if (rtc_fd == -1) {
warn(_("cannot open rtc device"));
return ret;
}
/* Turn on update interrupts (one per second) */
int rc = ioctl(rtc_fd, RTC_UIE_ON, 0);
if (rc != -1) {
/*
* Just reading rtc_fd fails on broken hardware: no
* update interrupt comes and a bootscript with a
* hwclock call hangs
*/
fd_set rfds;
struct timeval tv;
/*
* Wait up to ten seconds for the next update
* interrupt
*/
FD_ZERO(&rfds);
FD_SET(rtc_fd, &rfds);
tv.tv_sec = 10;
tv.tv_usec = 0;
rc = select(rtc_fd + 1, &rfds, NULL, NULL, &tv);
if (0 < rc)
ret = 0;
else if (rc == 0) {
warnx(_("select() to %s to wait for clock tick timed out"),
rtc_dev_name);
} else
warn(_("select() to %s to wait for clock tick failed"),
rtc_dev_name);
/* Turn off update interrupts */
rc = ioctl(rtc_fd, RTC_UIE_OFF, 0);
if (rc == -1)
warn(_("ioctl() to %s to turn off update interrupts failed"),
rtc_dev_name);
} else if (errno == ENOTTY || errno == EINVAL) {
/* rtc ioctl interrupts are unimplemented */
ret = busywait_for_rtc_clock_tick(ctl, rtc_fd);
} else
warn(_("ioctl(%d, RTC_UIE_ON, 0) to %s failed"),
rtc_fd, rtc_dev_name);
return ret;
}
static int read_hardware_clock_rtc(const struct hwclock_control *ctl,
struct tm *tm)
{
int rtc_fd, rc;
rtc_fd = open_rtc_or_exit(ctl);
/* Read the RTC time/date, return answer via tm */
rc = do_rtc_read_ioctl(rtc_fd, tm);
return rc;
}
/*
* Set the Hardware Clock to the broken down time <new_broken_time>. Use
* ioctls to "rtc" device /dev/rtc.
*/
static int set_hardware_clock_rtc(const struct hwclock_control *ctl,
const struct tm *new_broken_time)
{
int rc = -1;
int rtc_fd;
struct rtc_time rtc_tm = { 0 };
rtc_fd = open_rtc_or_exit(ctl);
/* kernel uses private struct tm definition to be self contained */
rtc_tm.tm_sec = new_broken_time->tm_sec;
rtc_tm.tm_min = new_broken_time->tm_min;
rtc_tm.tm_hour = new_broken_time->tm_hour;
rtc_tm.tm_mday = new_broken_time->tm_mday;
rtc_tm.tm_mon = new_broken_time->tm_mon;
rtc_tm.tm_year = new_broken_time->tm_year;
rtc_tm.tm_wday = new_broken_time->tm_wday;
rtc_tm.tm_yday = new_broken_time->tm_yday;
rtc_tm.tm_isdst = new_broken_time->tm_isdst;
rc = ioctl(rtc_fd, RTC_SET_TIME, &rtc_tm);
if (rc == -1) {
warn(_("ioctl(RTC_SET_TIME) to %s to set the time failed"),
rtc_dev_name);
hwclock_exit(ctl, EXIT_FAILURE);
}
if (ctl->verbose)
printf(_("ioctl(RTC_SET_TIME) was successful.\n"));
return 0;
}
static int get_permissions_rtc(void)
{
return 0;
}
static const char *get_device_path(void)
{
return rtc_dev_name;
}
static const struct clock_ops rtc_interface = {
N_("Using the rtc interface to the clock."),
get_permissions_rtc,
read_hardware_clock_rtc,
set_hardware_clock_rtc,
synchronize_to_clock_tick_rtc,
get_device_path,
};
/* return &rtc if /dev/rtc can be opened, NULL otherwise */
const struct clock_ops *probe_for_rtc_clock(const struct hwclock_control *ctl)
{
const int rtc_fd = open_rtc(ctl);
if (rtc_fd < 0)
return NULL;
return &rtc_interface;
}
#ifdef __alpha__
/*
* Get the Hardware Clock epoch setting from the kernel.
*/
int get_epoch_rtc(const struct hwclock_control *ctl, unsigned long *epoch_p)
{
int rtc_fd;
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_EPOCH_READ, epoch_p) == -1) {
warn(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s failed"),
rtc_fd, rtc_dev_name);
return 1;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s succeeded.\n"),
rtc_fd, rtc_dev_name);
return 0;
}
/*
* Set the Hardware Clock epoch in the kernel.
*/
int set_epoch_rtc(const struct hwclock_control *ctl)
{
int rtc_fd;
unsigned long epoch;
errno = 0;
epoch = strtoul(ctl->epoch_option, NULL, 10);
/* There were no RTC clocks before 1900. */
if (errno || epoch < 1900 || epoch == ULONG_MAX) {
warnx(_("invalid epoch '%s'."), ctl->epoch_option);
return 1;
}
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_EPOCH_SET, epoch) == -1) {
warn(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s failed"),
rtc_fd, epoch, rtc_dev_name);
return 1;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s succeeded.\n"),
rtc_fd, epoch, rtc_dev_name);
return 0;
}
#endif /* __alpha__ */
static int resolve_rtc_param_alias(const char *alias, __u64 *value)
{
const struct hwclock_param *param = &hwclock_params[0];
while (param->name) {
if (!strcmp(alias, param->name)) {
*value = param->id;
return 0;
}
param++;
}
return 1;
}
/* kernel uapi __u64 can be defined differently than uint64_t */
static int strtoku64(const char *str, __u64 *num, int base)
{
return ul_strtou64(str, (uint64_t *) num, base);
}
/*
* Get the Hardware Clock parameter setting from the kernel.
*/
int get_param_rtc(const struct hwclock_control *ctl,
const char *name, uint64_t *id, uint64_t *value)
{
int rtc_fd;
struct rtc_param param = { .param = 0 };
/* handle name */
if (resolve_rtc_param_alias(name, ¶m.param) != 0
&& strtoku64(name, ¶m.param, 0) != 0) {
warnx(_("could not convert parameter name to number"));
return 1;
}
/* get parameter */
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_PARAM_GET, ¶m) == -1) {
warn(_("ioctl(%d, RTC_PARAM_GET, param) to %s failed"),
rtc_fd, rtc_dev_name);
return 1;
}
if (id)
*id = param.param;
if (value)
*value = param.uvalue;
if (ctl->verbose)
printf(_("ioctl(%d, RTC_PARAM_GET, param) to %s succeeded.\n"),
rtc_fd, rtc_dev_name);
return 0;
}
/*
* Set the Hardware Clock parameter in the kernel.
*/
int set_param_rtc(const struct hwclock_control *ctl, const char *opt0)
{
int rtc_fd, rc = 1;
struct rtc_param param = { .param = 0 };
char *tok, *opt = xstrdup(opt0);
/* handle name */
tok = strtok(opt, "=");
if (resolve_rtc_param_alias(tok, ¶m.param) != 0
&& strtoku64(tok, ¶m.param, 0) != 0) {
warnx(_("could not convert parameter name to number"));
goto done;
}
/* handle value */
tok = strtok(NULL, "=");
if (!tok) {
warnx(_("expected <param>=<value>"));
goto done;
}
if (strtoku64(tok, ¶m.uvalue, 0) != 0) {
warnx(_("could not convert parameter value to number"));
goto done;
}
/* set parameter */
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warnx(_("cannot open %s"), rtc_dev_name);
goto done;
}
if (ioctl(rtc_fd, RTC_PARAM_SET, ¶m) == -1) {
warn(_("ioctl(%d, RTC_PARAM_SET, param) to %s failed"),
rtc_fd, rtc_dev_name);
goto done;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_PARAM_SET, param) to %s succeeded.\n"),
rtc_fd, rtc_dev_name);
rc = 0;
done:
free(opt);
return rc;
}
#ifndef RTC_VL_DATA_INVALID
#define RTC_VL_DATA_INVALID 0x1
#endif
#ifndef RTC_VL_BACKUP_LOW
#define RTC_VL_BACKUP_LOW 0x2
#endif
#ifndef RTC_VL_BACKUP_EMPTY
#define RTC_VL_BACKUP_EMPTY 0x4
#endif
#ifndef RTC_VL_ACCURACY_LOW
#define RTC_VL_ACCURACY_LOW 0x8
#endif
#ifndef RTC_VL_BACKUP_SWITCH
#define RTC_VL_BACKUP_SWITCH 0x10
#endif
int rtc_vl_read(const struct hwclock_control *ctl)
{
unsigned int vl;
int rtc_fd;
size_t i;
static const struct vl_bit {
unsigned int bit;
const char *desc;
} vl_bits[] = {
{ RTC_VL_DATA_INVALID, N_("Voltage too low, RTC data is invalid") },
{ RTC_VL_BACKUP_LOW, N_("Backup voltage is low") },
{ RTC_VL_BACKUP_EMPTY, N_("Backup empty or not present") },
{ RTC_VL_ACCURACY_LOW, N_("Voltage is low, RTC accuracy is reduced") },
{ RTC_VL_BACKUP_SWITCH, N_("Backup switchover happened") },
};
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warnx(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_VL_READ, &vl) == -1) {
warn(_("ioctl(%d, RTC_VL_READ) on %s failed"),
rtc_fd, rtc_dev_name);
return 1;
}
if (ctl->verbose) {
printf(_("ioctl(%d, RTC_VL_READ) on %s returned 0x%x\n"),
rtc_fd, rtc_dev_name, vl);
}
for (i = 0; i < ARRAY_SIZE(vl_bits); ++i) {
const struct vl_bit *vlb = &vl_bits[i];
if (vl & vlb->bit) {
printf("0x%02x - %s\n", vlb->bit, vlb->desc);
vl &= ~vlb->bit;
}
}
if (vl)
printf("0x%02x - unknown bit(s)\n", vl);
return 0;
}
int rtc_vl_clear(const struct hwclock_control *ctl)
{
int rtc_fd;
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warnx(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_VL_CLR) == -1) {
warn(_("ioctl(%d, RTC_VL_CLEAR) on %s failed"),
rtc_fd, rtc_dev_name);
return 1;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_VL_CLEAR) on %s succeeded.\n"),
rtc_fd, rtc_dev_name);
return 0;
}
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