diff options
| author | John Stultz <johnstul@us.ibm.com> | 2007-11-26 20:42:19 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-11-26 20:42:19 +0100 |
| commit | 52bfb36050c8529d9031d2c2513b281a360922ec (patch) | |
| tree | 7d116ece2ed21b8319e800efc0c2fd70818f01d3 | |
| parent | 8232fd625217dc641ed05dd238a8bb5c82828082 (diff) | |
time: add ADJ_OFFSET_SS_READ
Michael Kerrisk reported that a long standing bug in the adjtimex()
system call causes glibc's adjtime(3) function to deliver the wrong
results if 'delta' is NULL.
add the ADJ_OFFSET_SS_READ API detail, which will be used by glibc
to fix this API compatibility bug.
Also see: http://bugzilla.kernel.org/show_bug.cgi?id=6761
[ mingo@elte.hu: added patch description and made it backwards compatible ]
NOTE: the new flag is defined 0xa001 so that it returns -EINVAL on
older kernels - this way glibc can use it safely. Suggested by Ulrich
Drepper.
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | include/linux/timex.h | 1 | ||||
| -rw-r--r-- | kernel/time/ntp.c | 9 |
2 files changed, 7 insertions, 3 deletions
diff --git a/include/linux/timex.h b/include/linux/timex.h index 37ac3ff90fa..24c6a2b5951 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -137,6 +137,7 @@ struct timex { #define ADJ_TIMECONST 0x0020 /* pll time constant */ #define ADJ_TICK 0x4000 /* tick value */ #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */ +#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */ /* xntp 3.4 compatibility names */ #define MOD_OFFSET ADJ_OFFSET diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 14a2ecf2b31..e64efaf957e 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -249,10 +249,12 @@ int do_adjtimex(struct timex *txc) /* Now we validate the data before disabling interrupts */ - if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) + if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) { /* singleshot must not be used with any other mode bits */ - if (txc->modes != ADJ_OFFSET_SINGLESHOT) + if (txc->modes != ADJ_OFFSET_SINGLESHOT && + txc->modes != ADJ_OFFSET_SS_READ) return -EINVAL; + } if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET)) /* adjustment Offset limited to +- .512 seconds */ @@ -372,7 +374,8 @@ int do_adjtimex(struct timex *txc) leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0) result = TIME_ERROR; - if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) + if ((txc->modes == ADJ_OFFSET_SINGLESHOT) || + (txc->modes == ADJ_OFFSET_SS_READ)) txc->offset = save_adjust; else txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) * |