* tiny patch for sys_time() and sys_stime()
@ 2003-05-01 12:09 Urs Thuermann
0 siblings, 0 replies; only message in thread
From: Urs Thuermann @ 2003-05-01 12:09 UTC (permalink / raw)
To: linux-kernel
A couple of years ago, when some 2.0.x kernel was current, I did a
patch for the time() and stime() system call, which I also sent for
inclusion, AFAIR to LKML. However I didn't get any response to it.
Now I see that the patch went partially in, i.e. for the sys_time()
syscall but not sys_stime().
These syscalls were implemented as they are still in 2.0.40-rc6 and
2.2.25 like this
asmlinkage int sys_time(int * tloc)
{
int i;
/* SMP: This is fairly trivial. We grab CURRENT_TIME and
stuff it to user space. No side effects */
i = CURRENT_TIME;
if (tloc) {
if (put_user(i,tloc))
i = -EFAULT;
}
return i;
}
where CURRENT_TIME is defined as xtime.tv_sec and
asmlinkage int sys_stime(int * tptr)
{
int value;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (get_user(value, tptr))
return -EFAULT;
write_lock_irq(&xtime_lock);
xtime.tv_sec = value;
xtime.tv_usec = 0;
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
write_unlock_irq(&xtime_lock);
return 0;
}
Both calls do not take into account the hardware timer, which may
cause the time read or set to be offset by almost one tick.
sys_settimeofday() and sys_gettimeofday() do take into account the
value of the hardware timer (i8254 or tsc on x86).
My patch was to make sys_time() and sys_stime() to be just wrappers to
do_gettimeofday() and do_settimeofday(). In 2.4.17 this was done
for sys_time() but not sys_stime(). In 2.5.x the macro CURRENT_TIME
was replaced by an inline function get_seconds() which also only does
return the value of xtime.tv_sec.
I append patches for 2.0.40-rc6, 2.2.25, 2.4.20-rc1 and 2.5.68 which
make both, sys_time() and sys_stime() just wrappers for the
do_{get,set}timeofday() calls. This looks cleaner, eliminates a small
amount of code duplication of code already present in
do_{get,set}timeofday, and it reduces the possibility of overseeing
necessary changes, like the call to clock_was_set() in the 2.5.x
version of do_settimeofday() for some architectures.
For 2.5.x and 2.6 kernels I'd actually like too see these calls
eliminated completely, as is the case for alpha and ia64 already.
urs
diff -ru linux-2.0.40-rc6/kernel/time.c linux-2.0.40-rc6-ut/kernel/time.c
--- linux-2.0.40-rc6/kernel/time.c 1998-06-04 00:17:50.000000000 +0200
+++ linux-2.0.40-rc6-ut/kernel/time.c 2003-04-04 20:14:48.000000000 +0200
@@ -52,9 +52,11 @@
*/
asmlinkage int sys_time(int * tloc)
{
+ struct timeval now;
int i;
- i = CURRENT_TIME;
+ do_gettimeofday(&now);
+ i = now.tv_sec;
if (tloc) {
int error = verify_area(VERIFY_WRITE, tloc, sizeof(*tloc));
if (error)
@@ -73,6 +75,7 @@
asmlinkage int sys_stime(int * tptr)
{
int error, value;
+ struct timeval new_tv;
if (!suser())
return -EPERM;
@@ -80,15 +83,9 @@
if (error)
return error;
value = get_user(tptr);
- cli();
- xtime.tv_sec = value;
- xtime.tv_usec = 0;
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_state = TIME_ERROR; /* p. 24, (a) */
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
- sti();
+ new_tv.tv_sec = value;
+ new_tv.tv_usec = 0;
+ do_settimeofday(&new_tv);
return 0;
}
diff -ru linux-2.2.25/kernel/time.c linux-2.2.25-ut/kernel/time.c
--- linux-2.2.25/kernel/time.c 2001-03-25 18:31:02.000000000 +0200
+++ linux-2.2.25-ut/kernel/time.c 2003-04-04 18:18:17.000000000 +0200
@@ -73,11 +73,11 @@
*/
asmlinkage int sys_time(int * tloc)
{
+ struct timeval now;
int i;
- /* SMP: This is fairly trivial. We grab CURRENT_TIME and
- stuff it to user space. No side effects */
- i = CURRENT_TIME;
+ do_gettimeofday(&now);
+ i = now.tv_sec;
if (tloc) {
if (put_user(i,tloc))
i = -EFAULT;
@@ -95,19 +95,15 @@
asmlinkage int sys_stime(int * tptr)
{
int value;
+ struct timeval new_tv;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (get_user(value, tptr))
return -EFAULT;
- write_lock_irq(&xtime_lock);
- xtime.tv_sec = value;
- xtime.tv_usec = 0;
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
- write_unlock_irq(&xtime_lock);
+ new_tv.tv_sec = value;
+ new_tv.tv_usec = 0;
+ do_settimeofday(&new_tv);
return 0;
}
diff -ru linux-2.4.20-rc1/kernel/time.c linux-2.4.20-rc1-ut/kernel/time.c
--- linux-2.4.20-rc1/kernel/time.c 2003-04-04 17:41:41.000000000 +0200
+++ linux-2.4.20-rc1-ut/kernel/time.c 2003-04-04 20:39:14.000000000 +0200
@@ -74,21 +74,15 @@
asmlinkage long sys_stime(int * tptr)
{
int value;
+ struct timeval new_tv;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (get_user(value, tptr))
return -EFAULT;
- write_lock_irq(&xtime_lock);
- vxtime_lock();
- xtime.tv_sec = value;
- xtime.tv_usec = 0;
- vxtime_unlock();
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
- write_unlock_irq(&xtime_lock);
+ new_tv.tv_sec = value;
+ new_tv.tv_usec = 0;
+ do_settimeofday(&new_tv);
return 0;
}
diff -ru linux-2.5.68/kernel/time.c linux-2.5.68-ut/kernel/time.c
--- linux-2.5.68/kernel/time.c 2003-05-01 12:26:40.000000000 +0200
+++ linux-2.5.68-ut/kernel/time.c 2003-05-01 12:29:10.000000000 +0200
@@ -49,11 +49,11 @@
*/
asmlinkage long sys_time(int * tloc)
{
+ struct timeval now;
int i;
- /* SMP: This is fairly trivial. We grab CURRENT_TIME and
- stuff it to user space. No side effects */
- i = get_seconds();
+ do_gettimeofday(&now);
+ i = now.tv_sec;
if (tloc) {
if (put_user(i,tloc))
i = -EFAULT;
@@ -71,20 +71,15 @@
asmlinkage long sys_stime(int * tptr)
{
int value;
+ struct timeval new_tv;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (get_user(value, tptr))
return -EFAULT;
- write_seqlock_irq(&xtime_lock);
- xtime.tv_sec = value;
- xtime.tv_nsec = 0;
- last_time_offset = 0;
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
- write_sequnlock_irq(&xtime_lock);
+ new_tv.tv_sec = value;
+ new_tv.tv_usec = 0;
+ do_settimeofday(&new_tv);
return 0;
}
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