sanchayanmaity/minix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
minix/commands/ibm/backup.c
Ben Gras 9865aeaa79 Initial revision
2005-04-21 14:53:53 +00:00

398 lines
11 KiB
C
Raw Blame History

/* readclock - read the real time clock Authors: T. Holm & E. Froese */
/************************************************************************/
/* */
/* readclock.c */
/* */
/* Read the clock value from the 64 byte CMOS RAM */
/* area, then set system time. */
/* */
/* If the machine ID byte is 0xFC or 0xF8, the device */
/* /dev/mem exists and can be opened for reading, */
/* and no errors in the CMOS RAM are reported by the */
/* RTC, then the time is read from the clock RAM */
/* area maintained by the RTC. */
/* */
/* The clock RAM values are decoded and fed to mktime */
/* to make a time_t value, then stime(2) is called. */
/* */
/* This fails if: */
/* */
/* If the machine ID does not match 0xFC or 0xF8 (no */
/* error message.) */
/* */
/* If the machine ID is 0xFC or 0xF8 and /dev/mem */
/* is missing, or cannot be accessed. */
/* */
/* If the RTC reports errors in the CMOS RAM. */
/* */
/************************************************************************/
/* origination 1987-Dec-29 efth */
/* robustness 1990-Oct-06 C. Sylvain */
/* incorp. B. Evans ideas 1991-Jul-06 C. Sylvain */
/* set time & calibrate 1992-Dec-17 Kees J. Bot */
/* clock timezone 1993-Oct-10 Kees J. Bot */
/* set CMOS clock 1994-Jun-12 Kees J. Bot */
/************************************************************************/
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <signal.h>
#include <ibm/portio.h>
#include <ibm/cmos.h>
#include <sys/svrctl.h>
int nflag = 0; /* Tell what, but don't do it. */
int wflag = 0; /* Set the CMOS clock. */
int Wflag = 0; /* Also set the CMOS clock register bits. */
int y2kflag = 0; /* Interpret 1980 as 2000 for clock with Y2K bug. */
char clocktz[128]; /* Timezone of the clock. */
#define MACH_ID_ADDR 0xFFFFE /* BIOS Machine ID at FFFF:000E */
#define PC_AT 0xFC /* Machine ID byte for PC/AT,
PC/XT286, and PS/2 Models 50, 60 */
#define PS_386 0xF8 /* Machine ID byte for PS/2 Model 80 */
/* Manufacturers usually use the ID value of the IBM model they emulate.
* However some manufacturers, notably HP and COMPAQ, have had different
* ideas in the past.
*
* Machine ID byte information source:
* _The Programmer's PC Sourcebook_ by Thom Hogan,
* published by Microsoft Press
*/
void errmsg(char *s);
void get_time(struct tm *t);
int read_register(int reg_addr);
void set_time(struct tm *t);
void write_register(int reg_addr, int value);
int bcd_to_dec(int n);
int dec_to_bcd(int n);
void usage(void);
int main(int argc, char **argv)
{
struct tm time1;
struct tm time2;
struct tm tmnow;
char date[64];
time_t now, rtc;
int i, mem;
unsigned char mach_id, cmos_state;
struct sysgetenv sysgetenv;
/* Open /dev/mem to get access to physical memory. */
if ((mem = open("/dev/mem", O_RDONLY)) == -1) {
errmsg( "Permission denied." );
exit(1);
}
if (lseek(mem, (off_t) MACH_ID_ADDR, SEEK_SET) == -1
|| read(mem, (void *) &mach_id, sizeof(mach_id)) < 0) {
mach_id = -1;
}
if (mach_id != PS_386 && mach_id != PC_AT) {
errmsg( "Machine ID unknown." );
fprintf( stderr, "Machine ID byte = %02x\n", mach_id );
exit(1);
}
cmos_state = read_register(CMOS_STATUS);
if (cmos_state & (CS_LOST_POWER | CS_BAD_CHKSUM | CS_BAD_TIME)) {
errmsg( "CMOS RAM error(s) found..." );
fprintf( stderr, "CMOS state = 0x%02x\n", cmos_state );
if (cmos_state & CS_LOST_POWER)
errmsg( "RTC lost power. Reset CMOS RAM with SETUP." );
if (cmos_state & CS_BAD_CHKSUM)
errmsg( "CMOS RAM checksum is bad. Run SETUP." );
if (cmos_state & CS_BAD_TIME)
errmsg( "Time invalid in CMOS RAM. Reset clock." );
exit(1);
}
/* Process options. */
while (argc > 1) {
char *p = *++argv;
if (*p++ != '-') usage();
while (*p != 0) {
switch (*p++) {
case 'n': nflag = 1; break;
case 'w': wflag = 1; break;
case 'W': Wflag = 1; break;
case '2': y2kflag = 1; break;
default: usage();
}
}
argc--;
}
if (Wflag) wflag = 1; /* -W implies -w */
/* The hardware clock may run in a different time zone, likely GMT or
* winter time. Select that time zone.
*/
strcpy(clocktz, "TZ=");
sysgetenv.key = "TZ";
sysgetenv.keylen = 2+1;
sysgetenv.val = clocktz+3;
sysgetenv.vallen = sizeof(clocktz)-3;
if (svrctl(SYSGETENV, &sysgetenv) == 0) {
putenv(clocktz);
tzset();
}
/* Read the CMOS real time clock. */
for (i = 0; i < 10; i++) {
get_time(&time1);
now = time(NULL);
time1.tm_isdst = -1; /* Do timezone calculations. */
time2 = time1;
rtc= mktime(&time1); /* Transform to a time_t. */
if (rtc != -1) break;
fprintf(stderr,
"readclock: Invalid time read from CMOS RTC: %d-%02d-%02d %02d:%02d:%02d\n",
time2.tm_year+1900, time2.tm_mon+1, time2.tm_mday,
time2.tm_hour, time2.tm_min, time2.tm_sec);
sleep(5);
}
if (i == 10) exit(1);
if (!wflag) {
/* Set system time. */
if (nflag) {
printf("stime(%lu)\n", (unsigned long) rtc);
} else {
if (stime(&rtc) < 0) {
errmsg( "Not allowed to set time." );
exit(1);
}
}
tmnow = *localtime(&rtc);
if (strftime(date, sizeof(date),
"%a %b %d %H:%M:%S %Z %Y", &tmnow) != 0) {
if (date[8] == '0') date[8]= ' ';
printf("Result: %s\n", date);
}
} else {
/* Set the CMOS clock to the system time. */
tmnow = *localtime(&now);
if (nflag) {
printf("%04d-%02d-%02d %02d:%02d:%02d\n",
tmnow.tm_year + 1900,
tmnow.tm_mon + 1,
tmnow.tm_mday,
tmnow.tm_hour,
tmnow.tm_min,
tmnow.tm_sec);
} else {
set_time(&tmnow);
}
}
exit(0);
}
void errmsg(char *s)
{
static char *prompt = "readclock: ";
fprintf(stderr, "%s%s\n", prompt, s);
prompt = "";
}
/***********************************************************************/
/* */
/* get_time( time ) */
/* */
/* Update the structure pointed to by time with the current time */
/* as read from CMOS RAM of the RTC. */
/* If necessary, the time is converted into a binary format before */
/* being stored in the structure. */
/* */
/***********************************************************************/
int dead;
void timeout(int sig) { dead= 1; }
void get_time(struct tm *t)
{
int osec, n;
unsigned long i;
struct sigaction sa;
/* Start a timer to keep us from getting stuck on a dead clock. */
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = timeout;
sigaction(SIGALRM, &sa, NULL);
dead = 0;
alarm(5);
do {
osec = -1;
n = 0;
do {
if (dead) {
fprintf(stderr, "readclock: CMOS clock appears dead\n");
exit(1);
}
/* Clock update in progress? */
if (read_register(RTC_REG_A) & RTC_A_UIP) continue;
t->tm_sec = read_register(RTC_SEC);
if (t->tm_sec != osec) {
/* Seconds changed. First from -1, then because the
* clock ticked, which is what we're waiting for to
* get a precise reading.
*/
osec = t->tm_sec;
n++;
}
} while (n < 2);
/* Read the other registers. */
t->tm_min = read_register(RTC_MIN);
t->tm_hour = read_register(RTC_HOUR);
t->tm_mday = read_register(RTC_MDAY);
t->tm_mon = read_register(RTC_MONTH);
t->tm_year = read_register(RTC_YEAR);
/* Time stable? */
} while (read_register(RTC_SEC) != t->tm_sec
|| read_register(RTC_MIN) != t->tm_min
|| read_register(RTC_HOUR) != t->tm_hour
|| read_register(RTC_MDAY) != t->tm_mday
|| read_register(RTC_MONTH) != t->tm_mon
|| read_register(RTC_YEAR) != t->tm_year);
if ((read_register(RTC_REG_B) & RTC_B_DM_BCD) == 0) {
/* Convert BCD to binary (default RTC mode). */
t->tm_year = bcd_to_dec(t->tm_year);
t->tm_mon = bcd_to_dec(t->tm_mon);
t->tm_mday = bcd_to_dec(t->tm_mday);
t->tm_hour = bcd_to_dec(t->tm_hour);
t->tm_min = bcd_to_dec(t->tm_min);
t->tm_sec = bcd_to_dec(t->tm_sec);
}
t->tm_mon--; /* Counts from 0. */
/* Correct the year, good until 2080. */
if (t->tm_year < 80) t->tm_year += 100;
if (y2kflag) {
/* Clock with Y2K bug, interpret 1980 as 2000, good until 2020. */
if (t->tm_year < 100) t->tm_year += 20;
}
}
int read_register(int reg_addr)
{
int r;
intr_disable();
outb(RTC_INDEX, reg_addr);
r= inb(RTC_IO);
intr_enable();
return r;
}
/***********************************************************************/
/* */
/* set_time( time ) */
/* */
/* Set the CMOS RTC to the time found in the structure. */
/* */
/***********************************************************************/
void set_time(struct tm *t)
{
int regA, regB;
if (Wflag) {
/* Set A and B registers to their proper values according to the AT
* reference manual. (For if it gets messed up, but the BIOS doesn't
* repair it.)
*/
write_register(RTC_REG_A, RTC_A_DV_OK | RTC_A_RS_DEF);
write_register(RTC_REG_B, RTC_B_24);
}
/* Inhibit updates. */
regB= read_register(RTC_REG_B);
write_register(RTC_REG_B, regB | RTC_B_SET);
t->tm_mon++; /* Counts from 1. */
if (y2kflag) {
/* Set the clock back 20 years to avoid Y2K bug, good until 2020. */
if (t->tm_year >= 100) t->tm_year -= 20;
}
if ((regB & 0x04) == 0) {
/* Convert binary to BCD (default RTC mode) */
t->tm_year = dec_to_bcd(t->tm_year % 100);
t->tm_mon = dec_to_bcd(t->tm_mon);
t->tm_mday = dec_to_bcd(t->tm_mday);
t->tm_hour = dec_to_bcd(t->tm_hour);
t->tm_min = dec_to_bcd(t->tm_min);
t->tm_sec = dec_to_bcd(t->tm_sec);
}
write_register(RTC_YEAR, t->tm_year);
write_register(RTC_MONTH, t->tm_mon);
write_register(RTC_MDAY, t->tm_mday);
write_register(RTC_HOUR, t->tm_hour);
write_register(RTC_MIN, t->tm_min);
write_register(RTC_SEC, t->tm_sec);
/* Stop the clock. */
regA= read_register(RTC_REG_A);
write_register(RTC_REG_A, regA | RTC_A_DV_STOP);
/* Allow updates and restart the clock. */
write_register(RTC_REG_B, regB);
write_register(RTC_REG_A, regA);
}
void write_register(int reg_addr, int value)
{
intr_disable();
outb(RTC_INDEX, reg_addr);
outb(RTC_IO, value);
intr_enable();
}
int bcd_to_dec(int n)
{
return ((n >> 4) & 0x0F) * 10 + (n & 0x0F);
}
int dec_to_bcd(int n)
{
return ((n / 10) << 4) | (n % 10);
}
void usage(void)
{
fprintf(stderr, "Usage: readclock [-nwW2]\n");
exit(1);
}
Reference in a new issue View git blame Copy permalink