1 files changed, 139 insertions, 0 deletions
diff --git a/pkg/sentry/fs/proc/stat.go b/pkg/sentry/fs/proc/stat.go
new file mode 100644
index 000000000..dee836a05
--- /dev/null
+++ b/pkg/sentry/fs/proc/stat.go
@@ -0,0 +1,139 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package proc
+
+import (
+	"bytes"
+	"fmt"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/proc/seqfile"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+)
+
+// statData backs /proc/stat.
+type statData struct {
+	// k is the owning Kernel.
+	k *kernel.Kernel
+}
+
+// NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
+func (*statData) NeedsUpdate(generation int64) bool {
+	return true
+}
+
+// cpuStats contains the breakdown of CPU time for /proc/stat.
+type cpuStats struct {
+	// user is time spent in userspace tasks with non-positive niceness.
+	user uint64
+
+	// nice is time spent in userspace tasks with positive niceness.
+	nice uint64
+
+	// system is time spent in non-interrupt kernel context.
+	system uint64
+
+	// idle is time spent idle.
+	idle uint64
+
+	// ioWait is time spent waiting for IO.
+	ioWait uint64
+
+	// irq is time spent in interrupt context.
+	irq uint64
+
+	// softirq is time spent in software interrupt context.
+	softirq uint64
+
+	// steal is involuntary wait time.
+	steal uint64
+
+	// guest is time spent in guests with non-positive niceness.
+	guest uint64
+
+	// guestNice is time spent in guests with positive niceness.
+	guestNice uint64
+}
+
+// String implements fmt.Stringer.
+func (c cpuStats) String() string {
+	return fmt.Sprintf("%d %d %d %d %d %d %d %d %d %d", c.user, c.nice, c.system, c.idle, c.ioWait, c.irq, c.softirq, c.steal, c.guest, c.guestNice)
+}
+
+// ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
+func (s *statData) ReadSeqFileData(h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
+	if h != nil {
+		return nil, 0
+	}
+
+	var buf bytes.Buffer
+
+	// TODO: We currently export only zero CPU stats. We could
+	// at least provide some aggregate stats.
+	var cpu cpuStats
+	fmt.Fprintf(&buf, "cpu  %s\n", cpu)
+
+	for c, max := uint(0), s.k.ApplicationCores(); c < max; c++ {
+		fmt.Fprintf(&buf, "cpu%d %s\n", c, cpu)
+	}
+
+	// The total number of interrupts is dependent on the CPUs and PCI
+	// devices on the system. See arch_probe_nr_irqs.
+	//
+	// Since we don't report real interrupt stats, just choose an arbitrary
+	// value from a representative VM.
+	const numInterrupts = 256
+
+	// The Kernel doesn't handle real interrupts, so report all zeroes.
+	// TODO: We could count page faults as #PF.
+	fmt.Fprintf(&buf, "intr 0") // total
+	for i := 0; i < numInterrupts; i++ {
+		fmt.Fprintf(&buf, " 0")
+	}
+	fmt.Fprintf(&buf, "\n")
+
+	// Total number of context switches.
+	// TODO: Count this.
+	fmt.Fprintf(&buf, "ctxt 0\n")
+
+	// CLOCK_REALTIME timestamp from boot, in seconds.
+	fmt.Fprintf(&buf, "btime %d\n", s.k.Timekeeper().BootTime().Seconds())
+
+	// Total number of clones.
+	// TODO: Count this.
+	fmt.Fprintf(&buf, "processes 0\n")
+
+	// Number of runnable tasks.
+	// TODO: Count this.
+	fmt.Fprintf(&buf, "procs_running 0\n")
+
+	// Number of tasks waiting on IO.
+	// TODO: Count this.
+	fmt.Fprintf(&buf, "procs_blocked 0\n")
+
+	// Number of each softirq handled.
+	fmt.Fprintf(&buf, "softirq 0") // total
+	for i := 0; i < linux.NumSoftIRQ; i++ {
+		fmt.Fprintf(&buf, " 0")
+	}
+	fmt.Fprintf(&buf, "\n")
+
+	return []seqfile.SeqData{
+		{
+			Buf:    buf.Bytes(),
+			Handle: (*statData)(nil),
+		},
+	}, 0
+}