[CRIU] [PATCHv3 04/27] timens: Introduce CLOCK_BOOTTIME offset

[Dmitry Safonov]

From: Andrei Vagin <avagin at openvz.org>

Adds boottime virtualisation for time namespace.
Introduce timespec for boottime clock into timens offsets and wire
clock_gettime() syscall.

Signed-off-by: Andrei Vagin <avagin at gmail.com>
Co-developed-by: Dmitry Safonov <dima at arista.com>
Signed-off-by: Dmitry Safonov <dima at arista.com>
---
 include/linux/time_namespace.h | 9 +++++++++
 include/linux/timens_offsets.h | 1 +
 kernel/time/alarmtimer.c       | 8 +++++++-
 kernel/time/posix-stubs.c      | 1 +
 kernel/time/posix-timers.c     | 2 ++
 5 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index 8f75d34cf34a..5f0da6858b10 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -48,6 +48,14 @@ static inline void timens_add_monotonic(struct timespec64 *ts)
                 *ts = timespec64_add(*ts, ns_offsets->monotonic_time_offset);
 }
 
+static inline void timens_add_boottime(struct timespec64 *ts)
+{
+        struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
+
+        if (ns_offsets)
+                *ts = timespec64_add(*ts, ns_offsets->monotonic_boottime_offset);
+}
+
 #else
 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
 {
@@ -73,6 +81,7 @@ static inline int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *ts
 }
 
 static inline void timens_add_monotonic(struct timespec64 *ts) {}
+static inline void timens_add_boottime(struct timespec64 *ts) {}
 #endif
 
 #endif /* _LINUX_TIMENS_H */
diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
index 248b0c0bb92a..777530c46852 100644
--- a/include/linux/timens_offsets.h
+++ b/include/linux/timens_offsets.h
@@ -4,6 +4,7 @@
 
 struct timens_offsets {
 	struct timespec64  monotonic_time_offset;
+	struct timespec64  monotonic_boottime_offset;
 };
 
 #endif
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 0519a8805aab..31f99361342e 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -653,12 +653,18 @@ static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp
  */
 static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
 {
-	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
+	struct alarm_base *base;
+
+	base = &alarm_bases[clock2alarm(which_clock & ~CLOCK_TIMENS)];
 
 	if (!alarmtimer_get_rtcdev())
 		return -EINVAL;
 
 	*tp = ktime_to_timespec64(base->gettime());
+
+	if (which_clock == (CLOCK_BOOTTIME_ALARM | CLOCK_TIMENS))
+		timens_add_boottime(tp);
+
 	return 0;
 }
 
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 17c67e0aecd8..edaf075d1ee4 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -82,6 +82,7 @@ int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 		break;
 	case CLOCK_BOOTTIME:
 		ktime_get_boottime_ts64(tp);
+		timens_add_boottime(tp);
 		break;
 	default:
 		return -EINVAL;
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index a047d6b7c768..a723e63d55fd 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -232,6 +232,8 @@ static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *
 static int posix_get_boottime(const clockid_t which_clock, struct timespec64 *tp)
 {
 	ktime_get_boottime_ts64(tp);
+	if (which_clock & CLOCK_TIMENS)
+		timens_add_boottime(tp);
 	return 0;
 }
 
-- 
2.21.0