Merge release-20200323.0-177-g12bde95 (automated)

1 files changed, 380 insertions, 0 deletions

diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
new file mode 100755
index 000000000..4621e2de0
--- /dev/null
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
@@ -0,0 +1,380 @@
+// Copyright 2019 The gVisor Authors.
+//
+// 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"
+	"strconv"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/time"
+	"gvisor.dev/gvisor/pkg/sentry/usage"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+type selfSymlink struct {
+	kernfs.InodeAttrs
+	kernfs.InodeNoopRefCount
+	kernfs.InodeSymlink
+
+	pidns *kernel.PIDNamespace
+}
+
+var _ kernfs.Inode = (*selfSymlink)(nil)
+
+func newSelfSymlink(creds *auth.Credentials, ino uint64, pidns *kernel.PIDNamespace) *kernfs.Dentry {
+	inode := &selfSymlink{pidns: pidns}
+	inode.Init(creds, ino, linux.ModeSymlink|0777)
+
+	d := &kernfs.Dentry{}
+	d.Init(inode)
+	return d
+}
+
+func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
+	t := kernel.TaskFromContext(ctx)
+	if t == nil {
+		// Who is reading this link?
+		return "", syserror.EINVAL
+	}
+	tgid := s.pidns.IDOfThreadGroup(t.ThreadGroup())
+	if tgid == 0 {
+		return "", syserror.ENOENT
+	}
+	return strconv.FormatUint(uint64(tgid), 10), nil
+}
+
+func (s *selfSymlink) Getlink(ctx context.Context) (vfs.VirtualDentry, string, error) {
+	target, err := s.Readlink(ctx)
+	return vfs.VirtualDentry{}, target, err
+}
+
+// SetStat implements Inode.SetStat not allowing inode attributes to be changed.
+func (*selfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+	return syserror.EPERM
+}
+
+type threadSelfSymlink struct {
+	kernfs.InodeAttrs
+	kernfs.InodeNoopRefCount
+	kernfs.InodeSymlink
+
+	pidns *kernel.PIDNamespace
+}
+
+var _ kernfs.Inode = (*threadSelfSymlink)(nil)
+
+func newThreadSelfSymlink(creds *auth.Credentials, ino uint64, pidns *kernel.PIDNamespace) *kernfs.Dentry {
+	inode := &threadSelfSymlink{pidns: pidns}
+	inode.Init(creds, ino, linux.ModeSymlink|0777)
+
+	d := &kernfs.Dentry{}
+	d.Init(inode)
+	return d
+}
+
+func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
+	t := kernel.TaskFromContext(ctx)
+	if t == nil {
+		// Who is reading this link?
+		return "", syserror.EINVAL
+	}
+	tgid := s.pidns.IDOfThreadGroup(t.ThreadGroup())
+	tid := s.pidns.IDOfTask(t)
+	if tid == 0 || tgid == 0 {
+		return "", syserror.ENOENT
+	}
+	return fmt.Sprintf("%d/task/%d", tgid, tid), nil
+}
+
+func (s *threadSelfSymlink) Getlink(ctx context.Context) (vfs.VirtualDentry, string, error) {
+	target, err := s.Readlink(ctx)
+	return vfs.VirtualDentry{}, target, err
+}
+
+// SetStat implements Inode.SetStat not allowing inode attributes to be changed.
+func (*threadSelfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+	return syserror.EPERM
+}
+
+// dynamicBytesFileSetAttr implements a special file that allows inode
+// attributes to be set. This is to support /proc files that are readonly, but
+// allow attributes to be set.
+type dynamicBytesFileSetAttr struct {
+	kernfs.DynamicBytesFile
+}
+
+// SetStat implements Inode.SetStat.
+func (d *dynamicBytesFileSetAttr) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+	return d.DynamicBytesFile.InodeAttrs.SetStat(ctx, fs, creds, opts)
+}
+
+// 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)
+}
+
+// statData implements vfs.DynamicBytesSource for /proc/stat.
+//
+// +stateify savable
+type statData struct {
+	dynamicBytesFileSetAttr
+}
+
+var _ dynamicInode = (*statData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*statData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	// TODO(b/37226836): 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)
+
+	k := kernel.KernelFromContext(ctx)
+	for c, max := uint(0), 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(b/37226836): 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(b/37226836): Count this.
+	fmt.Fprintf(buf, "ctxt 0\n")
+
+	// CLOCK_REALTIME timestamp from boot, in seconds.
+	fmt.Fprintf(buf, "btime %d\n", k.Timekeeper().BootTime().Seconds())
+
+	// Total number of clones.
+	// TODO(b/37226836): Count this.
+	fmt.Fprintf(buf, "processes 0\n")
+
+	// Number of runnable tasks.
+	// TODO(b/37226836): Count this.
+	fmt.Fprintf(buf, "procs_running 0\n")
+
+	// Number of tasks waiting on IO.
+	// TODO(b/37226836): 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 nil
+}
+
+// loadavgData backs /proc/loadavg.
+//
+// +stateify savable
+type loadavgData struct {
+	dynamicBytesFileSetAttr
+}
+
+var _ dynamicInode = (*loadavgData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*loadavgData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	// TODO(b/62345059): Include real data in fields.
+	// Column 1-3: CPU and IO utilization of the last 1, 5, and 10 minute periods.
+	// Column 4-5: currently running processes and the total number of processes.
+	// Column 6: the last process ID used.
+	fmt.Fprintf(buf, "%.2f %.2f %.2f %d/%d %d\n", 0.00, 0.00, 0.00, 0, 0, 0)
+	return nil
+}
+
+// meminfoData implements vfs.DynamicBytesSource for /proc/meminfo.
+//
+// +stateify savable
+type meminfoData struct {
+	dynamicBytesFileSetAttr
+}
+
+var _ dynamicInode = (*meminfoData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*meminfoData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	k := kernel.KernelFromContext(ctx)
+	mf := k.MemoryFile()
+	mf.UpdateUsage()
+	snapshot, totalUsage := usage.MemoryAccounting.Copy()
+	totalSize := usage.TotalMemory(mf.TotalSize(), totalUsage)
+	anon := snapshot.Anonymous + snapshot.Tmpfs
+	file := snapshot.PageCache + snapshot.Mapped
+	// We don't actually have active/inactive LRUs, so just make up numbers.
+	activeFile := (file / 2) &^ (usermem.PageSize - 1)
+	inactiveFile := file - activeFile
+
+	fmt.Fprintf(buf, "MemTotal:       %8d kB\n", totalSize/1024)
+	memFree := (totalSize - totalUsage) / 1024
+	// We use MemFree as MemAvailable because we don't swap.
+	// TODO(rahat): When reclaim is implemented the value of MemAvailable
+	// should change.
+	fmt.Fprintf(buf, "MemFree:        %8d kB\n", memFree)
+	fmt.Fprintf(buf, "MemAvailable:   %8d kB\n", memFree)
+	fmt.Fprintf(buf, "Buffers:               0 kB\n") // memory usage by block devices
+	fmt.Fprintf(buf, "Cached:         %8d kB\n", (file+snapshot.Tmpfs)/1024)
+	// Emulate a system with no swap, which disables inactivation of anon pages.
+	fmt.Fprintf(buf, "SwapCache:             0 kB\n")
+	fmt.Fprintf(buf, "Active:         %8d kB\n", (anon+activeFile)/1024)
+	fmt.Fprintf(buf, "Inactive:       %8d kB\n", inactiveFile/1024)
+	fmt.Fprintf(buf, "Active(anon):   %8d kB\n", anon/1024)
+	fmt.Fprintf(buf, "Inactive(anon):        0 kB\n")
+	fmt.Fprintf(buf, "Active(file):   %8d kB\n", activeFile/1024)
+	fmt.Fprintf(buf, "Inactive(file): %8d kB\n", inactiveFile/1024)
+	fmt.Fprintf(buf, "Unevictable:           0 kB\n") // TODO(b/31823263)
+	fmt.Fprintf(buf, "Mlocked:               0 kB\n") // TODO(b/31823263)
+	fmt.Fprintf(buf, "SwapTotal:             0 kB\n")
+	fmt.Fprintf(buf, "SwapFree:              0 kB\n")
+	fmt.Fprintf(buf, "Dirty:                 0 kB\n")
+	fmt.Fprintf(buf, "Writeback:             0 kB\n")
+	fmt.Fprintf(buf, "AnonPages:      %8d kB\n", anon/1024)
+	fmt.Fprintf(buf, "Mapped:         %8d kB\n", file/1024) // doesn't count mapped tmpfs, which we don't know
+	fmt.Fprintf(buf, "Shmem:          %8d kB\n", snapshot.Tmpfs/1024)
+	return nil
+}
+
+// uptimeData implements vfs.DynamicBytesSource for /proc/uptime.
+//
+// +stateify savable
+type uptimeData struct {
+	dynamicBytesFileSetAttr
+}
+
+var _ dynamicInode = (*uptimeData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*uptimeData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	k := kernel.KernelFromContext(ctx)
+	now := time.NowFromContext(ctx)
+
+	// Pretend that we've spent zero time sleeping (second number).
+	fmt.Fprintf(buf, "%.2f 0.00\n", now.Sub(k.Timekeeper().BootTime()).Seconds())
+	return nil
+}
+
+// versionData implements vfs.DynamicBytesSource for /proc/version.
+//
+// +stateify savable
+type versionData struct {
+	dynamicBytesFileSetAttr
+}
+
+var _ dynamicInode = (*versionData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*versionData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	k := kernel.KernelFromContext(ctx)
+	init := k.GlobalInit()
+	if init == nil {
+		// Attempted to read before the init Task is created. This can
+		// only occur during startup, which should never need to read
+		// this file.
+		panic("Attempted to read version before initial Task is available")
+	}
+
+	// /proc/version takes the form:
+	//
+	// "SYSNAME version RELEASE (COMPILE_USER@COMPILE_HOST)
+	// (COMPILER_VERSION) VERSION"
+	//
+	// where:
+	// - SYSNAME, RELEASE, and VERSION are the same as returned by
+	// sys_utsname
+	// - COMPILE_USER is the user that build the kernel
+	// - COMPILE_HOST is the hostname of the machine on which the kernel
+	// was built
+	// - COMPILER_VERSION is the version reported by the building compiler
+	//
+	// Since we don't really want to expose build information to
+	// applications, those fields are omitted.
+	//
+	// FIXME(mpratt): Using Version from the init task SyscallTable
+	// disregards the different version a task may have (e.g., in a uts
+	// namespace).
+	ver := init.Leader().SyscallTable().Version
+	fmt.Fprintf(buf, "%s version %s %s\n", ver.Sysname, ver.Release, ver.Version)
+	return nil
+}
+
+// filesystemsData backs /proc/filesystems.
+//
+// +stateify savable
+type filesystemsData struct {
+	kernfs.DynamicBytesFile
+}
+
+var _ dynamicInode = (*filesystemsData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *filesystemsData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	k := kernel.KernelFromContext(ctx)
+	k.VFS().GenerateProcFilesystems(buf)
+	return nil
+}