Add time namespace, which contains an offset from the system time.
In a namespace, gettimeofday gets the system time and adds the
namespace offset to it. settimeofday, which is unprivileged in a
namespace, calculates the difference between the system time and the
new namespace time and sets that as the namespace offset.
Index: linux-2.6.17-mm-vtime/kernel/time.c
===================================================================
--- linux-2.6.17-mm-vtime.orig/kernel/time.c 2006-04-13 13:48:03.000000000
-0400
+++ linux-2.6.17-mm-vtime/kernel/time.c 2006-04-13 13:48:32.000000000 -0400
@@ -103,6 +103,11 @@ asmlinkage long sys_gettimeofday(struct
if (likely(tv != NULL)) {
struct timeval ktv;
do_gettimeofday(&ktv);
+ if(current->time_ns != NULL){
+ s64 now = timeval_to_ns(&ktv);
+ now += current->time_ns->offset;
+ ktv = ns_to_timeval(now);
+ }
if (copy_to_user(tv, &ktv, sizeof(ktv)))
return -EFAULT;
}
@@ -158,6 +163,18 @@ int do_sys_settimeofday(struct timespec
if (tv && !timespec_valid(tv))
return -EINVAL;
+ if(current->time_ns != NULL){
+ struct timeval now;
+ s64 old, new;
+
+ do_gettimeofday(&now);
+ old = timeval_to_ns(&now);
+ new = timespec_to_ns(tv);
+ current->time_ns->offset = new - old;
+
+ return 0;
+ }
+
error = security_settime(tv, tz);
if (error)
return error;
Index: linux-2.6.17-mm-vtime/include/linux/sched.h
===================================================================
--- linux-2.6.17-mm-vtime.orig/include/linux/sched.h 2006-04-13
13:48:03.000000000 -0400
+++ linux-2.6.17-mm-vtime/include/linux/sched.h 2006-04-13 13:48:32.000000000
-0400
@@ -715,6 +715,11 @@ enum sleep_type {
SLEEP_INTERRUPTED,
};
+struct time_ns {
+ atomic_t counter;
+ s64 offset;
+};
+
struct task_struct {
volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
struct thread_info *thread_info;
@@ -838,6 +843,7 @@ struct task_struct {
/* signal handlers */
struct signal_struct *signal;
struct sighand_struct *sighand;
+ struct time_ns *time_ns;
sigset_t blocked, real_blocked;
sigset_t saved_sigmask; /* To be restored with
TIF_RESTORE_SIGMASK */
Index: linux-2.6.17-mm-vtime/include/linux/init_task.h
===================================================================
--- linux-2.6.17-mm-vtime.orig/include/linux/init_task.h 2006-04-13
13:48:03.000000000 -0400
+++ linux-2.6.17-mm-vtime/include/linux/init_task.h 2006-04-13
13:48:32.000000000 -0400
@@ -98,6 +98,7 @@ extern struct group_info init_groups;
.tasks = LIST_HEAD_INIT(tsk.tasks), \
.ptrace_children= LIST_HEAD_INIT(tsk.ptrace_children), \
.ptrace_list = LIST_HEAD_INIT(tsk.ptrace_list), \
+ .time_ns = NULL, \
.real_parent = &tsk, \
.parent = &tsk, \
.children = LIST_HEAD_INIT(tsk.children), \
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