diff options
Diffstat (limited to 'pkg/sentry/kernel')
29 files changed, 807 insertions, 250 deletions
diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD index aba2414d4..e041c51b3 100644 --- a/pkg/sentry/kernel/BUILD +++ b/pkg/sentry/kernel/BUILD @@ -1,12 +1,11 @@ load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library") load("@io_bazel_rules_go//go:def.bzl", "go_test") load("@rules_cc//cc:defs.bzl", "cc_proto_library") - -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "pending_signals_list", out = "pending_signals_list.go", diff --git a/pkg/sentry/kernel/auth/BUILD b/pkg/sentry/kernel/auth/BUILD index 1d00a6310..51de4568a 100644 --- a/pkg/sentry/kernel/auth/BUILD +++ b/pkg/sentry/kernel/auth/BUILD @@ -1,8 +1,8 @@ -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "atomicptr_credentials", out = "atomicptr_credentials_unsafe.go", diff --git a/pkg/sentry/kernel/context.go b/pkg/sentry/kernel/context.go index e3f5b0d83..3c9dceaba 100644 --- a/pkg/sentry/kernel/context.go +++ b/pkg/sentry/kernel/context.go @@ -15,6 +15,8 @@ package kernel import ( + "time" + "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/context" ) @@ -97,6 +99,21 @@ func TaskFromContext(ctx context.Context) *Task { return nil } +// Deadline implements context.Context.Deadline. +func (*Task) Deadline() (time.Time, bool) { + return time.Time{}, false +} + +// Done implements context.Context.Done. +func (*Task) Done() <-chan struct{} { + return nil +} + +// Err implements context.Context.Err. +func (*Task) Err() error { + return nil +} + // AsyncContext returns a context.Context that may be used by goroutines that // do work on behalf of t and therefore share its contextual values, but are // not t's task goroutine (e.g. asynchronous I/O). @@ -129,6 +146,21 @@ func (ctx taskAsyncContext) IsLogging(level log.Level) bool { return ctx.t.IsLogging(level) } +// Deadline implements context.Context.Deadline. +func (ctx taskAsyncContext) Deadline() (time.Time, bool) { + return ctx.t.Deadline() +} + +// Done implements context.Context.Done. +func (ctx taskAsyncContext) Done() <-chan struct{} { + return ctx.t.Done() +} + +// Err implements context.Context.Err. +func (ctx taskAsyncContext) Err() error { + return ctx.t.Err() +} + // Value implements context.Context.Value. func (ctx taskAsyncContext) Value(key interface{}) interface{} { return ctx.t.Value(key) diff --git a/pkg/sentry/kernel/contexttest/BUILD b/pkg/sentry/kernel/contexttest/BUILD index bec13a3d9..3a88a585c 100644 --- a/pkg/sentry/kernel/contexttest/BUILD +++ b/pkg/sentry/kernel/contexttest/BUILD @@ -1,7 +1,7 @@ -package(licenses = ["notice"]) - load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_library( name = "contexttest", testonly = 1, diff --git a/pkg/sentry/kernel/epoll/BUILD b/pkg/sentry/kernel/epoll/BUILD index 65427b112..3361e8b7d 100644 --- a/pkg/sentry/kernel/epoll/BUILD +++ b/pkg/sentry/kernel/epoll/BUILD @@ -1,10 +1,9 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test") - -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "epoll_list", out = "epoll_list.go", diff --git a/pkg/sentry/kernel/eventfd/BUILD b/pkg/sentry/kernel/eventfd/BUILD index 983ca67ed..e65b961e8 100644 --- a/pkg/sentry/kernel/eventfd/BUILD +++ b/pkg/sentry/kernel/eventfd/BUILD @@ -1,9 +1,8 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test") +load("//tools/go_stateify:defs.bzl", "go_library") package(licenses = ["notice"]) -load("//tools/go_stateify:defs.bzl", "go_library") - go_library( name = "eventfd", srcs = ["eventfd.go"], diff --git a/pkg/sentry/kernel/fasync/BUILD b/pkg/sentry/kernel/fasync/BUILD index 5eddca115..49d81b712 100644 --- a/pkg/sentry/kernel/fasync/BUILD +++ b/pkg/sentry/kernel/fasync/BUILD @@ -1,7 +1,7 @@ -package(licenses = ["notice"]) - load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_library( name = "fasync", srcs = ["fasync.go"], diff --git a/pkg/sentry/kernel/fd_table.go b/pkg/sentry/kernel/fd_table.go index cc3f43a45..11f613a11 100644 --- a/pkg/sentry/kernel/fd_table.go +++ b/pkg/sentry/kernel/fd_table.go @@ -81,6 +81,9 @@ type FDTable struct { // mu protects below. mu sync.Mutex `state:"nosave"` + // next is start position to find fd. + next int32 + // used contains the number of non-nil entries. It must be accessed // atomically. It may be read atomically without holding mu (but not // written). @@ -226,6 +229,11 @@ func (f *FDTable) NewFDs(ctx context.Context, fd int32, files []*fs.File, flags f.mu.Lock() defer f.mu.Unlock() + // From f.next to find available fd. + if fd < f.next { + fd = f.next + } + // Install all entries. for i := fd; i < end && len(fds) < len(files); i++ { if d, _, _ := f.get(i); d == nil { @@ -242,6 +250,11 @@ func (f *FDTable) NewFDs(ctx context.Context, fd int32, files []*fs.File, flags return nil, syscall.EMFILE } + if fd == f.next { + // Update next search start position. + f.next = fds[len(fds)-1] + 1 + } + return fds, nil } @@ -361,6 +374,11 @@ func (f *FDTable) Remove(fd int32) *fs.File { f.mu.Lock() defer f.mu.Unlock() + // Update current available position. + if fd < f.next { + f.next = fd + } + orig, _, _ := f.get(fd) if orig != nil { orig.IncRef() // Reference for caller. @@ -377,6 +395,10 @@ func (f *FDTable) RemoveIf(cond func(*fs.File, FDFlags) bool) { f.forEach(func(fd int32, file *fs.File, flags FDFlags) { if cond(file, flags) { f.set(fd, nil, FDFlags{}) // Clear from table. + // Update current available position. + if fd < f.next { + f.next = fd + } } }) } diff --git a/pkg/sentry/kernel/fd_table_test.go b/pkg/sentry/kernel/fd_table_test.go index 2413788e7..2bcb6216a 100644 --- a/pkg/sentry/kernel/fd_table_test.go +++ b/pkg/sentry/kernel/fd_table_test.go @@ -70,6 +70,42 @@ func TestFDTableMany(t *testing.T) { if err := fdTable.NewFDAt(ctx, 1, file, FDFlags{}); err != nil { t.Fatalf("fdTable.NewFDAt(1, r, FDFlags{}): got %v, wanted nil", err) } + + i := int32(2) + fdTable.Remove(i) + if fds, err := fdTable.NewFDs(ctx, 0, []*fs.File{file}, FDFlags{}); err != nil || fds[0] != i { + t.Fatalf("Allocated %v FDs but wanted to allocate %v: %v", i, maxFD, err) + } + }) +} + +func TestFDTableOverLimit(t *testing.T) { + runTest(t, func(ctx context.Context, fdTable *FDTable, file *fs.File, _ *limits.LimitSet) { + if _, err := fdTable.NewFDs(ctx, maxFD, []*fs.File{file}, FDFlags{}); err == nil { + t.Fatalf("fdTable.NewFDs(maxFD, f): got nil, wanted error") + } + + if _, err := fdTable.NewFDs(ctx, maxFD-2, []*fs.File{file, file, file}, FDFlags{}); err == nil { + t.Fatalf("fdTable.NewFDs(maxFD-2, {f,f,f}): got nil, wanted error") + } + + if fds, err := fdTable.NewFDs(ctx, maxFD-3, []*fs.File{file, file, file}, FDFlags{}); err != nil { + t.Fatalf("fdTable.NewFDs(maxFD-3, {f,f,f}): got %v, wanted nil", err) + } else { + for _, fd := range fds { + fdTable.Remove(fd) + } + } + + if fds, err := fdTable.NewFDs(ctx, maxFD-1, []*fs.File{file}, FDFlags{}); err != nil || fds[0] != maxFD-1 { + t.Fatalf("fdTable.NewFDAt(1, r, FDFlags{}): got %v, wanted nil", err) + } + + if fds, err := fdTable.NewFDs(ctx, 0, []*fs.File{file}, FDFlags{}); err != nil { + t.Fatalf("Adding an FD to a resized map: got %v, want nil", err) + } else if len(fds) != 1 || fds[0] != 0 { + t.Fatalf("Added an FD to a resized map: got %v, want {1}", fds) + } }) } diff --git a/pkg/sentry/kernel/futex/BUILD b/pkg/sentry/kernel/futex/BUILD index 41f44999c..34286c7a8 100644 --- a/pkg/sentry/kernel/futex/BUILD +++ b/pkg/sentry/kernel/futex/BUILD @@ -1,10 +1,9 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test") - -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "atomicptr_bucket", out = "atomicptr_bucket_unsafe.go", diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go index 8c1f79ab5..28ba950bd 100644 --- a/pkg/sentry/kernel/kernel.go +++ b/pkg/sentry/kernel/kernel.go @@ -24,6 +24,7 @@ // TaskSet.mu // SignalHandlers.mu // Task.mu +// runningTasksMu // // Locking SignalHandlers.mu in multiple SignalHandlers requires locking // TaskSet.mu exclusively first. Locking Task.mu in multiple Tasks at the same @@ -135,6 +136,22 @@ type Kernel struct { // syslog is the kernel log. syslog syslog + // runningTasksMu synchronizes disable/enable of cpuClockTicker when + // the kernel is idle (runningTasks == 0). + // + // runningTasksMu is used to exclude critical sections when the timer + // disables itself and when the first active task enables the timer, + // ensuring that tasks always see a valid cpuClock value. + runningTasksMu sync.Mutex `state:"nosave"` + + // runningTasks is the total count of tasks currently in + // TaskGoroutineRunningSys or TaskGoroutineRunningApp. i.e., they are + // not blocked or stopped. + // + // runningTasks must be accessed atomically. Increments from 0 to 1 are + // further protected by runningTasksMu (see incRunningTasks). + runningTasks int64 + // cpuClock is incremented every linux.ClockTick. cpuClock is used to // measure task CPU usage, since sampling monotonicClock twice on every // syscall turns out to be unreasonably expensive. This is similar to how @@ -150,6 +167,22 @@ type Kernel struct { // cpuClockTicker increments cpuClock. cpuClockTicker *ktime.Timer `state:"nosave"` + // cpuClockTickerDisabled indicates that cpuClockTicker has been + // disabled because no tasks are running. + // + // cpuClockTickerDisabled is protected by runningTasksMu. + cpuClockTickerDisabled bool + + // cpuClockTickerSetting is the ktime.Setting of cpuClockTicker at the + // point it was disabled. It is cached here to avoid a lock ordering + // violation with cpuClockTicker.mu when runningTaskMu is held. + // + // cpuClockTickerSetting is only valid when cpuClockTickerDisabled is + // true. + // + // cpuClockTickerSetting is protected by runningTasksMu. + cpuClockTickerSetting ktime.Setting + // fdMapUids is an ever-increasing counter for generating FDTable uids. // // fdMapUids is mutable, and is accessed using atomic memory operations. @@ -358,7 +391,7 @@ func (k *Kernel) SaveTo(w io.Writer) error { // // N.B. This will also be saved along with the full kernel save below. cpuidStart := time.Now() - if err := state.Save(w, k.FeatureSet(), nil); err != nil { + if err := state.Save(k.SupervisorContext(), w, k.FeatureSet(), nil); err != nil { return err } log.Infof("CPUID save took [%s].", time.Since(cpuidStart)) @@ -366,7 +399,7 @@ func (k *Kernel) SaveTo(w io.Writer) error { // Save the kernel state. kernelStart := time.Now() var stats state.Stats - if err := state.Save(w, k, &stats); err != nil { + if err := state.Save(k.SupervisorContext(), w, k, &stats); err != nil { return err } log.Infof("Kernel save stats: %s", &stats) @@ -374,7 +407,7 @@ func (k *Kernel) SaveTo(w io.Writer) error { // Save the memory file's state. memoryStart := time.Now() - if err := k.mf.SaveTo(w); err != nil { + if err := k.mf.SaveTo(k.SupervisorContext(), w); err != nil { return err } log.Infof("Memory save took [%s].", time.Since(memoryStart)) @@ -509,7 +542,7 @@ func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) // don't need to explicitly install it in the Kernel. cpuidStart := time.Now() var features cpuid.FeatureSet - if err := state.Load(r, &features, nil); err != nil { + if err := state.Load(k.SupervisorContext(), r, &features, nil); err != nil { return err } log.Infof("CPUID load took [%s].", time.Since(cpuidStart)) @@ -525,7 +558,7 @@ func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) // Load the kernel state. kernelStart := time.Now() var stats state.Stats - if err := state.Load(r, k, &stats); err != nil { + if err := state.Load(k.SupervisorContext(), r, k, &stats); err != nil { return err } log.Infof("Kernel load stats: %s", &stats) @@ -533,7 +566,7 @@ func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) // Load the memory file's state. memoryStart := time.Now() - if err := k.mf.LoadFrom(r); err != nil { + if err := k.mf.LoadFrom(k.SupervisorContext(), r); err != nil { return err } log.Infof("Memory load took [%s].", time.Since(memoryStart)) @@ -771,8 +804,21 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID, // Create a fresh task context. remainingTraversals = uint(args.MaxSymlinkTraversals) + loadArgs := loader.LoadArgs{ + Mounts: mounts, + Root: root, + WorkingDirectory: wd, + RemainingTraversals: &remainingTraversals, + ResolveFinal: true, + Filename: args.Filename, + File: args.File, + CloseOnExec: false, + Argv: args.Argv, + Envv: args.Envv, + Features: k.featureSet, + } - tc, se := k.LoadTaskImage(ctx, mounts, root, wd, &remainingTraversals, args.Filename, args.File, args.Argv, args.Envv, k.featureSet) + tc, se := k.LoadTaskImage(ctx, loadArgs) if se != nil { return nil, 0, errors.New(se.String()) } @@ -912,6 +958,102 @@ func (k *Kernel) resumeTimeLocked() { } } +func (k *Kernel) incRunningTasks() { + for { + tasks := atomic.LoadInt64(&k.runningTasks) + if tasks != 0 { + // Standard case. Simply increment. + if !atomic.CompareAndSwapInt64(&k.runningTasks, tasks, tasks+1) { + continue + } + return + } + + // Transition from 0 -> 1. Synchronize with other transitions and timer. + k.runningTasksMu.Lock() + tasks = atomic.LoadInt64(&k.runningTasks) + if tasks != 0 { + // We're no longer the first task, no need to + // re-enable. + atomic.AddInt64(&k.runningTasks, 1) + k.runningTasksMu.Unlock() + return + } + + if !k.cpuClockTickerDisabled { + // Timer was never disabled. + atomic.StoreInt64(&k.runningTasks, 1) + k.runningTasksMu.Unlock() + return + } + + // We need to update cpuClock for all of the ticks missed while we + // slept, and then re-enable the timer. + // + // The Notify in Swap isn't sufficient. kernelCPUClockTicker.Notify + // always increments cpuClock by 1 regardless of the number of + // expirations as a heuristic to avoid over-accounting in cases of CPU + // throttling. + // + // We want to cover the normal case, when all time should be accounted, + // so we increment for all expirations. Throttling is less concerning + // here because the ticker is only disabled from Notify. This means + // that Notify must schedule and compensate for the throttled period + // before the timer is disabled. Throttling while the timer is disabled + // doesn't matter, as nothing is running or reading cpuClock anyways. + // + // S/R also adds complication, as there are two cases. Recall that + // monotonicClock will jump forward on restore. + // + // 1. If the ticker is enabled during save, then on Restore Notify is + // called with many expirations, covering the time jump, but cpuClock + // is only incremented by 1. + // + // 2. If the ticker is disabled during save, then after Restore the + // first wakeup will call this function and cpuClock will be + // incremented by the number of expirations across the S/R. + // + // These cause very different value of cpuClock. But again, since + // nothing was running while the ticker was disabled, those differences + // don't matter. + setting, exp := k.cpuClockTickerSetting.At(k.monotonicClock.Now()) + if exp > 0 { + atomic.AddUint64(&k.cpuClock, exp) + } + + // Now that cpuClock is updated it is safe to allow other tasks to + // transition to running. + atomic.StoreInt64(&k.runningTasks, 1) + + // N.B. we must unlock before calling Swap to maintain lock ordering. + // + // cpuClockTickerDisabled need not wait until after Swap to become + // true. It is sufficient that the timer *will* be enabled. + k.cpuClockTickerDisabled = false + k.runningTasksMu.Unlock() + + // This won't call Notify (unless it's been ClockTick since setting.At + // above). This means we skip the thread group work in Notify. However, + // since nothing was running while we were disabled, none of the timers + // could have expired. + k.cpuClockTicker.Swap(setting) + + return + } +} + +func (k *Kernel) decRunningTasks() { + tasks := atomic.AddInt64(&k.runningTasks, -1) + if tasks < 0 { + panic(fmt.Sprintf("Invalid running count %d", tasks)) + } + + // Nothing to do. The next CPU clock tick will disable the timer if + // there is still nothing running. This provides approximately one tick + // of slack in which we can switch back and forth between idle and + // active without an expensive transition. +} + // WaitExited blocks until all tasks in k have exited. func (k *Kernel) WaitExited() { k.tasks.liveGoroutines.Wait() @@ -1180,6 +1322,7 @@ func (k *Kernel) ListSockets() []*SocketEntry { return socks } +// supervisorContext is a privileged context. type supervisorContext struct { context.NoopSleeper log.Logger diff --git a/pkg/sentry/kernel/pipe/BUILD b/pkg/sentry/kernel/pipe/BUILD index 2ce8952e2..9d34f6d4d 100644 --- a/pkg/sentry/kernel/pipe/BUILD +++ b/pkg/sentry/kernel/pipe/BUILD @@ -1,10 +1,9 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test") - -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "buffer_list", out = "buffer_list.go", @@ -25,8 +24,10 @@ go_library( "device.go", "node.go", "pipe.go", + "pipe_util.go", "reader.go", "reader_writer.go", + "vfs.go", "writer.go", ], importpath = "gvisor.dev/gvisor/pkg/sentry/kernel/pipe", @@ -41,6 +42,7 @@ go_library( "//pkg/sentry/fs/fsutil", "//pkg/sentry/safemem", "//pkg/sentry/usermem", + "//pkg/sentry/vfs", "//pkg/syserror", "//pkg/waiter", ], diff --git a/pkg/sentry/kernel/pipe/node.go b/pkg/sentry/kernel/pipe/node.go index a2dc72204..4a19ab7ce 100644 --- a/pkg/sentry/kernel/pipe/node.go +++ b/pkg/sentry/kernel/pipe/node.go @@ -18,7 +18,6 @@ import ( "sync" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/amutex" "gvisor.dev/gvisor/pkg/sentry/context" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" @@ -91,10 +90,10 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi switch { case flags.Read && !flags.Write: // O_RDONLY. r := i.p.Open(ctx, d, flags) - i.newHandleLocked(&i.rWakeup) + newHandleLocked(&i.rWakeup) if i.p.isNamed && !flags.NonBlocking && !i.p.HasWriters() { - if !i.waitFor(&i.wWakeup, ctx) { + if !waitFor(&i.mu, &i.wWakeup, ctx) { r.DecRef() return nil, syserror.ErrInterrupted } @@ -107,7 +106,7 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi case flags.Write && !flags.Read: // O_WRONLY. w := i.p.Open(ctx, d, flags) - i.newHandleLocked(&i.wWakeup) + newHandleLocked(&i.wWakeup) if i.p.isNamed && !i.p.HasReaders() { // On a nonblocking, write-only open, the open fails with ENXIO if the @@ -117,7 +116,7 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi return nil, syserror.ENXIO } - if !i.waitFor(&i.rWakeup, ctx) { + if !waitFor(&i.mu, &i.rWakeup, ctx) { w.DecRef() return nil, syserror.ErrInterrupted } @@ -127,8 +126,8 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi case flags.Read && flags.Write: // O_RDWR. // Pipes opened for read-write always succeeds without blocking. rw := i.p.Open(ctx, d, flags) - i.newHandleLocked(&i.rWakeup) - i.newHandleLocked(&i.wWakeup) + newHandleLocked(&i.rWakeup) + newHandleLocked(&i.wWakeup) return rw, nil default: @@ -136,65 +135,6 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi } } -// waitFor blocks until the underlying pipe has at least one reader/writer is -// announced via 'wakeupChan', or until 'sleeper' is cancelled. Any call to this -// function will block for either readers or writers, depending on where -// 'wakeupChan' points. -// -// f.mu must be held by the caller. waitFor returns with f.mu held, but it will -// drop f.mu before blocking for any reader/writers. -func (i *inodeOperations) waitFor(wakeupChan *chan struct{}, sleeper amutex.Sleeper) bool { - // Ideally this function would simply use a condition variable. However, the - // wait needs to be interruptible via 'sleeper', so we must sychronize via a - // channel. The synchronization below relies on the fact that closing a - // channel unblocks all receives on the channel. - - // Does an appropriate wakeup channel already exist? If not, create a new - // one. This is all done under f.mu to avoid races. - if *wakeupChan == nil { - *wakeupChan = make(chan struct{}) - } - - // Grab a local reference to the wakeup channel since it may disappear as - // soon as we drop f.mu. - wakeup := *wakeupChan - - // Drop the lock and prepare to sleep. - i.mu.Unlock() - cancel := sleeper.SleepStart() - - // Wait for either a new reader/write to be signalled via 'wakeup', or - // for the sleep to be cancelled. - select { - case <-wakeup: - sleeper.SleepFinish(true) - case <-cancel: - sleeper.SleepFinish(false) - } - - // Take the lock and check if we were woken. If we were woken and - // interrupted, the former takes priority. - i.mu.Lock() - select { - case <-wakeup: - return true - default: - return false - } -} - -// newHandleLocked signals a new pipe reader or writer depending on where -// 'wakeupChan' points. This unblocks any corresponding reader or writer -// waiting for the other end of the channel to be opened, see Fifo.waitFor. -// -// i.mu must be held. -func (*inodeOperations) newHandleLocked(wakeupChan *chan struct{}) { - if *wakeupChan != nil { - close(*wakeupChan) - *wakeupChan = nil - } -} - func (*inodeOperations) Allocate(_ context.Context, _ *fs.Inode, _, _ int64) error { return syserror.EPIPE } diff --git a/pkg/sentry/kernel/pipe/node_test.go b/pkg/sentry/kernel/pipe/node_test.go index adbad7764..16fa80abe 100644 --- a/pkg/sentry/kernel/pipe/node_test.go +++ b/pkg/sentry/kernel/pipe/node_test.go @@ -85,11 +85,11 @@ func testOpen(ctx context.Context, t *testing.T, n fs.InodeOperations, flags fs. } func newNamedPipe(t *testing.T) *Pipe { - return NewPipe(contexttest.Context(t), true, DefaultPipeSize, usermem.PageSize) + return NewPipe(true, DefaultPipeSize, usermem.PageSize) } func newAnonPipe(t *testing.T) *Pipe { - return NewPipe(contexttest.Context(t), false, DefaultPipeSize, usermem.PageSize) + return NewPipe(false, DefaultPipeSize, usermem.PageSize) } // assertRecvBlocks ensures that a recv attempt on c blocks for at least diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go index 93b50669f..1a1b38f83 100644 --- a/pkg/sentry/kernel/pipe/pipe.go +++ b/pkg/sentry/kernel/pipe/pipe.go @@ -98,7 +98,7 @@ type Pipe struct { // NewPipe initializes and returns a pipe. // // N.B. The size and atomicIOBytes will be bounded. -func NewPipe(ctx context.Context, isNamed bool, sizeBytes, atomicIOBytes int64) *Pipe { +func NewPipe(isNamed bool, sizeBytes, atomicIOBytes int64) *Pipe { if sizeBytes < MinimumPipeSize { sizeBytes = MinimumPipeSize } @@ -111,17 +111,33 @@ func NewPipe(ctx context.Context, isNamed bool, sizeBytes, atomicIOBytes int64) if atomicIOBytes > sizeBytes { atomicIOBytes = sizeBytes } - return &Pipe{ - isNamed: isNamed, - max: sizeBytes, - atomicIOBytes: atomicIOBytes, + var p Pipe + initPipe(&p, isNamed, sizeBytes, atomicIOBytes) + return &p +} + +func initPipe(pipe *Pipe, isNamed bool, sizeBytes, atomicIOBytes int64) { + if sizeBytes < MinimumPipeSize { + sizeBytes = MinimumPipeSize + } + if sizeBytes > MaximumPipeSize { + sizeBytes = MaximumPipeSize + } + if atomicIOBytes <= 0 { + atomicIOBytes = 1 + } + if atomicIOBytes > sizeBytes { + atomicIOBytes = sizeBytes } + pipe.isNamed = isNamed + pipe.max = sizeBytes + pipe.atomicIOBytes = atomicIOBytes } // NewConnectedPipe initializes a pipe and returns a pair of objects // representing the read and write ends of the pipe. func NewConnectedPipe(ctx context.Context, sizeBytes, atomicIOBytes int64) (*fs.File, *fs.File) { - p := NewPipe(ctx, false /* isNamed */, sizeBytes, atomicIOBytes) + p := NewPipe(false /* isNamed */, sizeBytes, atomicIOBytes) // Build an fs.Dirent for the pipe which will be shared by both // returned files. diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go new file mode 100644 index 000000000..ef9641e6a --- /dev/null +++ b/pkg/sentry/kernel/pipe/pipe_util.go @@ -0,0 +1,213 @@ +// 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 pipe + +import ( + "io" + "math" + "sync" + "syscall" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/amutex" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +// This file contains Pipe file functionality that is tied to neither VFS nor +// the old fs architecture. + +// Release cleans up the pipe's state. +func (p *Pipe) Release() { + p.rClose() + p.wClose() + + // Wake up readers and writers. + p.Notify(waiter.EventIn | waiter.EventOut) +} + +// Read reads from the Pipe into dst. +func (p *Pipe) Read(ctx context.Context, dst usermem.IOSequence) (int64, error) { + n, err := p.read(ctx, readOps{ + left: func() int64 { + return dst.NumBytes() + }, + limit: func(l int64) { + dst = dst.TakeFirst64(l) + }, + read: func(buf *buffer) (int64, error) { + n, err := dst.CopyOutFrom(ctx, buf) + dst = dst.DropFirst64(n) + return n, err + }, + }) + if n > 0 { + p.Notify(waiter.EventOut) + } + return n, err +} + +// WriteTo writes to w from the Pipe. +func (p *Pipe) WriteTo(ctx context.Context, w io.Writer, count int64, dup bool) (int64, error) { + ops := readOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + read: func(buf *buffer) (int64, error) { + n, err := buf.ReadToWriter(w, count, dup) + count -= n + return n, err + }, + } + if dup { + // There is no notification for dup operations. + return p.dup(ctx, ops) + } + n, err := p.read(ctx, ops) + if n > 0 { + p.Notify(waiter.EventOut) + } + return n, err +} + +// Write writes to the Pipe from src. +func (p *Pipe) Write(ctx context.Context, src usermem.IOSequence) (int64, error) { + n, err := p.write(ctx, writeOps{ + left: func() int64 { + return src.NumBytes() + }, + limit: func(l int64) { + src = src.TakeFirst64(l) + }, + write: func(buf *buffer) (int64, error) { + n, err := src.CopyInTo(ctx, buf) + src = src.DropFirst64(n) + return n, err + }, + }) + if n > 0 { + p.Notify(waiter.EventIn) + } + return n, err +} + +// ReadFrom reads from r to the Pipe. +func (p *Pipe) ReadFrom(ctx context.Context, r io.Reader, count int64) (int64, error) { + n, err := p.write(ctx, writeOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + write: func(buf *buffer) (int64, error) { + n, err := buf.WriteFromReader(r, count) + count -= n + return n, err + }, + }) + if n > 0 { + p.Notify(waiter.EventIn) + } + return n, err +} + +// Readiness returns the ready events in the underlying pipe. +func (p *Pipe) Readiness(mask waiter.EventMask) waiter.EventMask { + return p.rwReadiness() & mask +} + +// Ioctl implements ioctls on the Pipe. +func (p *Pipe) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { + // Switch on ioctl request. + switch int(args[1].Int()) { + case linux.FIONREAD: + v := p.queued() + if v > math.MaxInt32 { + v = math.MaxInt32 // Silently truncate. + } + // Copy result to user-space. + _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{ + AddressSpaceActive: true, + }) + return 0, err + default: + return 0, syscall.ENOTTY + } +} + +// waitFor blocks until the underlying pipe has at least one reader/writer is +// announced via 'wakeupChan', or until 'sleeper' is cancelled. Any call to this +// function will block for either readers or writers, depending on where +// 'wakeupChan' points. +// +// mu must be held by the caller. waitFor returns with mu held, but it will +// drop mu before blocking for any reader/writers. +func waitFor(mu *sync.Mutex, wakeupChan *chan struct{}, sleeper amutex.Sleeper) bool { + // Ideally this function would simply use a condition variable. However, the + // wait needs to be interruptible via 'sleeper', so we must sychronize via a + // channel. The synchronization below relies on the fact that closing a + // channel unblocks all receives on the channel. + + // Does an appropriate wakeup channel already exist? If not, create a new + // one. This is all done under f.mu to avoid races. + if *wakeupChan == nil { + *wakeupChan = make(chan struct{}) + } + + // Grab a local reference to the wakeup channel since it may disappear as + // soon as we drop f.mu. + wakeup := *wakeupChan + + // Drop the lock and prepare to sleep. + mu.Unlock() + cancel := sleeper.SleepStart() + + // Wait for either a new reader/write to be signalled via 'wakeup', or + // for the sleep to be cancelled. + select { + case <-wakeup: + sleeper.SleepFinish(true) + case <-cancel: + sleeper.SleepFinish(false) + } + + // Take the lock and check if we were woken. If we were woken and + // interrupted, the former takes priority. + mu.Lock() + select { + case <-wakeup: + return true + default: + return false + } +} + +// newHandleLocked signals a new pipe reader or writer depending on where +// 'wakeupChan' points. This unblocks any corresponding reader or writer +// waiting for the other end of the channel to be opened, see Fifo.waitFor. +// +// Precondition: the mutex protecting wakeupChan must be held. +func newHandleLocked(wakeupChan *chan struct{}) { + if *wakeupChan != nil { + close(*wakeupChan) + *wakeupChan = nil + } +} diff --git a/pkg/sentry/kernel/pipe/reader_writer.go b/pkg/sentry/kernel/pipe/reader_writer.go index 7c307f013..b4d29fc77 100644 --- a/pkg/sentry/kernel/pipe/reader_writer.go +++ b/pkg/sentry/kernel/pipe/reader_writer.go @@ -16,16 +16,12 @@ package pipe import ( "io" - "math" - "syscall" - "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/context" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" "gvisor.dev/gvisor/pkg/sentry/usermem" - "gvisor.dev/gvisor/pkg/waiter" ) // ReaderWriter satisfies the FileOperations interface and services both @@ -45,124 +41,27 @@ type ReaderWriter struct { *Pipe } -// Release implements fs.FileOperations.Release. -func (rw *ReaderWriter) Release() { - rw.Pipe.rClose() - rw.Pipe.wClose() - - // Wake up readers and writers. - rw.Pipe.Notify(waiter.EventIn | waiter.EventOut) -} - // Read implements fs.FileOperations.Read. func (rw *ReaderWriter) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, _ int64) (int64, error) { - n, err := rw.Pipe.read(ctx, readOps{ - left: func() int64 { - return dst.NumBytes() - }, - limit: func(l int64) { - dst = dst.TakeFirst64(l) - }, - read: func(buf *buffer) (int64, error) { - n, err := dst.CopyOutFrom(ctx, buf) - dst = dst.DropFirst64(n) - return n, err - }, - }) - if n > 0 { - rw.Pipe.Notify(waiter.EventOut) - } - return n, err + return rw.Pipe.Read(ctx, dst) } // WriteTo implements fs.FileOperations.WriteTo. func (rw *ReaderWriter) WriteTo(ctx context.Context, _ *fs.File, w io.Writer, count int64, dup bool) (int64, error) { - ops := readOps{ - left: func() int64 { - return count - }, - limit: func(l int64) { - count = l - }, - read: func(buf *buffer) (int64, error) { - n, err := buf.ReadToWriter(w, count, dup) - count -= n - return n, err - }, - } - if dup { - // There is no notification for dup operations. - return rw.Pipe.dup(ctx, ops) - } - n, err := rw.Pipe.read(ctx, ops) - if n > 0 { - rw.Pipe.Notify(waiter.EventOut) - } - return n, err + return rw.Pipe.WriteTo(ctx, w, count, dup) } // Write implements fs.FileOperations.Write. func (rw *ReaderWriter) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) { - n, err := rw.Pipe.write(ctx, writeOps{ - left: func() int64 { - return src.NumBytes() - }, - limit: func(l int64) { - src = src.TakeFirst64(l) - }, - write: func(buf *buffer) (int64, error) { - n, err := src.CopyInTo(ctx, buf) - src = src.DropFirst64(n) - return n, err - }, - }) - if n > 0 { - rw.Pipe.Notify(waiter.EventIn) - } - return n, err + return rw.Pipe.Write(ctx, src) } // ReadFrom implements fs.FileOperations.WriteTo. func (rw *ReaderWriter) ReadFrom(ctx context.Context, _ *fs.File, r io.Reader, count int64) (int64, error) { - n, err := rw.Pipe.write(ctx, writeOps{ - left: func() int64 { - return count - }, - limit: func(l int64) { - count = l - }, - write: func(buf *buffer) (int64, error) { - n, err := buf.WriteFromReader(r, count) - count -= n - return n, err - }, - }) - if n > 0 { - rw.Pipe.Notify(waiter.EventIn) - } - return n, err -} - -// Readiness returns the ready events in the underlying pipe. -func (rw *ReaderWriter) Readiness(mask waiter.EventMask) waiter.EventMask { - return rw.Pipe.rwReadiness() & mask + return rw.Pipe.ReadFrom(ctx, r, count) } // Ioctl implements fs.FileOperations.Ioctl. func (rw *ReaderWriter) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { - // Switch on ioctl request. - switch int(args[1].Int()) { - case linux.FIONREAD: - v := rw.queued() - if v > math.MaxInt32 { - v = math.MaxInt32 // Silently truncate. - } - // Copy result to user-space. - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{ - AddressSpaceActive: true, - }) - return 0, err - default: - return 0, syscall.ENOTTY - } + return rw.Pipe.Ioctl(ctx, io, args) } diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go new file mode 100644 index 000000000..6416e0dd8 --- /dev/null +++ b/pkg/sentry/kernel/pipe/vfs.go @@ -0,0 +1,220 @@ +// 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 pipe + +import ( + "sync" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/waiter" +) + +// This file contains types enabling the pipe package to be used with the vfs +// package. + +// VFSPipe represents the actual pipe, analagous to an inode. VFSPipes should +// not be copied. +type VFSPipe struct { + // mu protects the fields below. + mu sync.Mutex `state:"nosave"` + + // pipe is the underlying pipe. + pipe Pipe + + // Channels for synchronizing the creation of new readers and writers + // of this fifo. See waitFor and newHandleLocked. + // + // These are not saved/restored because all waiters are unblocked on + // save, and either automatically restart (via ERESTARTSYS) or return + // EINTR on resume. On restarts via ERESTARTSYS, the appropriate + // channel will be recreated. + rWakeup chan struct{} `state:"nosave"` + wWakeup chan struct{} `state:"nosave"` +} + +// NewVFSPipe returns an initialized VFSPipe. +func NewVFSPipe(sizeBytes, atomicIOBytes int64) *VFSPipe { + var vp VFSPipe + initPipe(&vp.pipe, true /* isNamed */, sizeBytes, atomicIOBytes) + return &vp +} + +// NewVFSPipeFD opens a named pipe. Named pipes have special blocking semantics +// during open: +// +// "Normally, opening the FIFO blocks until the other end is opened also. A +// process can open a FIFO in nonblocking mode. In this case, opening for +// read-only will succeed even if no-one has opened on the write side yet, +// opening for write-only will fail with ENXIO (no such device or address) +// unless the other end has already been opened. Under Linux, opening a FIFO +// for read and write will succeed both in blocking and nonblocking mode. POSIX +// leaves this behavior undefined. This can be used to open a FIFO for writing +// while there are no readers available." - fifo(7) +func (vp *VFSPipe) NewVFSPipeFD(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, vfsfd *vfs.FileDescription, flags uint32) (*VFSPipeFD, error) { + vp.mu.Lock() + defer vp.mu.Unlock() + + readable := vfs.MayReadFileWithOpenFlags(flags) + writable := vfs.MayWriteFileWithOpenFlags(flags) + if !readable && !writable { + return nil, syserror.EINVAL + } + + vfd, err := vp.open(rp, vfsd, vfsfd, flags) + if err != nil { + return nil, err + } + + switch { + case readable && writable: + // Pipes opened for read-write always succeed without blocking. + newHandleLocked(&vp.rWakeup) + newHandleLocked(&vp.wWakeup) + + case readable: + newHandleLocked(&vp.rWakeup) + // If this pipe is being opened as nonblocking and there's no + // writer, we have to wait for a writer to open the other end. + if flags&linux.O_NONBLOCK == 0 && !vp.pipe.HasWriters() && !waitFor(&vp.mu, &vp.wWakeup, ctx) { + return nil, syserror.EINTR + } + + case writable: + newHandleLocked(&vp.wWakeup) + + if !vp.pipe.HasReaders() { + // Nonblocking, write-only opens fail with ENXIO when + // the read side isn't open yet. + if flags&linux.O_NONBLOCK != 0 { + return nil, syserror.ENXIO + } + // Wait for a reader to open the other end. + if !waitFor(&vp.mu, &vp.rWakeup, ctx) { + return nil, syserror.EINTR + } + } + + default: + panic("invalid pipe flags: must be readable, writable, or both") + } + + return vfd, nil +} + +// Preconditions: vp.mu must be held. +func (vp *VFSPipe) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, vfsfd *vfs.FileDescription, flags uint32) (*VFSPipeFD, error) { + var fd VFSPipeFD + fd.flags = flags + fd.readable = vfs.MayReadFileWithOpenFlags(flags) + fd.writable = vfs.MayWriteFileWithOpenFlags(flags) + fd.vfsfd = vfsfd + fd.pipe = &vp.pipe + if fd.writable { + // The corresponding Mount.EndWrite() is in VFSPipe.Release(). + if err := rp.Mount().CheckBeginWrite(); err != nil { + return nil, err + } + } + + switch { + case fd.readable && fd.writable: + vp.pipe.rOpen() + vp.pipe.wOpen() + case fd.readable: + vp.pipe.rOpen() + case fd.writable: + vp.pipe.wOpen() + default: + panic("invalid pipe flags: must be readable, writable, or both") + } + + return &fd, nil +} + +// VFSPipeFD implements a subset of vfs.FileDescriptionImpl for pipes. It is +// expected that filesystesm will use this in a struct implementing +// vfs.FileDescriptionImpl. +type VFSPipeFD struct { + pipe *Pipe + flags uint32 + readable bool + writable bool + vfsfd *vfs.FileDescription +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *VFSPipeFD) Release() { + var event waiter.EventMask + if fd.readable { + fd.pipe.rClose() + event |= waiter.EventIn + } + if fd.writable { + fd.pipe.wClose() + event |= waiter.EventOut + } + if event == 0 { + panic("invalid pipe flags: must be readable, writable, or both") + } + + if fd.writable { + fd.vfsfd.VirtualDentry().Mount().EndWrite() + } + + fd.pipe.Notify(event) +} + +// OnClose implements vfs.FileDescriptionImpl.OnClose. +func (fd *VFSPipeFD) OnClose(_ context.Context) error { + return nil +} + +// PRead implements vfs.FileDescriptionImpl.PRead. +func (fd *VFSPipeFD) PRead(_ context.Context, _ usermem.IOSequence, _ int64, _ vfs.ReadOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// Read implements vfs.FileDescriptionImpl.Read. +func (fd *VFSPipeFD) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) { + if !fd.readable { + return 0, syserror.EINVAL + } + + return fd.pipe.Read(ctx, dst) +} + +// PWrite implements vfs.FileDescriptionImpl.PWrite. +func (fd *VFSPipeFD) PWrite(_ context.Context, _ usermem.IOSequence, _ int64, _ vfs.WriteOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// Write implements vfs.FileDescriptionImpl.Write. +func (fd *VFSPipeFD) Write(ctx context.Context, src usermem.IOSequence, _ vfs.WriteOptions) (int64, error) { + if !fd.writable { + return 0, syserror.EINVAL + } + + return fd.pipe.Write(ctx, src) +} + +// Ioctl implements vfs.FileDescriptionImpl.Ioctl. +func (fd *VFSPipeFD) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { + return fd.pipe.Ioctl(ctx, uio, args) +} diff --git a/pkg/sentry/kernel/posixtimer.go b/pkg/sentry/kernel/posixtimer.go index c5d095af7..2e861a5a8 100644 --- a/pkg/sentry/kernel/posixtimer.go +++ b/pkg/sentry/kernel/posixtimer.go @@ -117,9 +117,9 @@ func (it *IntervalTimer) signalRejectedLocked() { } // Notify implements ktime.TimerListener.Notify. -func (it *IntervalTimer) Notify(exp uint64) { +func (it *IntervalTimer) Notify(exp uint64, setting ktime.Setting) (ktime.Setting, bool) { if it.target == nil { - return + return ktime.Setting{}, false } it.target.tg.pidns.owner.mu.RLock() @@ -129,7 +129,7 @@ func (it *IntervalTimer) Notify(exp uint64) { if it.sigpending { it.overrunCur += exp - return + return ktime.Setting{}, false } // sigpending must be set before sendSignalTimerLocked() so that it can be @@ -148,6 +148,8 @@ func (it *IntervalTimer) Notify(exp uint64) { if err := it.target.sendSignalTimerLocked(si, it.group, it); err != nil { it.signalRejectedLocked() } + + return ktime.Setting{}, false } // Destroy implements ktime.TimerListener.Destroy. Users of Timer should call diff --git a/pkg/sentry/kernel/semaphore/BUILD b/pkg/sentry/kernel/semaphore/BUILD index 80e5e5da3..f4c00cd86 100644 --- a/pkg/sentry/kernel/semaphore/BUILD +++ b/pkg/sentry/kernel/semaphore/BUILD @@ -1,10 +1,9 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test") - -package(licenses = ["notice"]) - load("//tools/go_generics:defs.bzl", "go_template_instance") load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_template_instance( name = "waiter_list", out = "waiter_list.go", diff --git a/pkg/sentry/kernel/shm/BUILD b/pkg/sentry/kernel/shm/BUILD index aa7471eb6..cd48945e6 100644 --- a/pkg/sentry/kernel/shm/BUILD +++ b/pkg/sentry/kernel/shm/BUILD @@ -1,7 +1,7 @@ -package(licenses = ["notice"]) - load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_library( name = "shm", srcs = [ diff --git a/pkg/sentry/kernel/signalfd/signalfd.go b/pkg/sentry/kernel/signalfd/signalfd.go index 06fd5ec88..4b08d7d72 100644 --- a/pkg/sentry/kernel/signalfd/signalfd.go +++ b/pkg/sentry/kernel/signalfd/signalfd.go @@ -121,7 +121,10 @@ func (s *SignalOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOS // Readiness implements waiter.Waitable.Readiness. func (s *SignalOperations) Readiness(mask waiter.EventMask) waiter.EventMask { - return mask & waiter.EventIn + if mask&waiter.EventIn != 0 && s.target.PendingSignals()&s.Mask() != 0 { + return waiter.EventIn // Pending signals. + } + return 0 } // EventRegister implements waiter.Waitable.EventRegister. diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go index c82ef5486..9be3dae3c 100644 --- a/pkg/sentry/kernel/task.go +++ b/pkg/sentry/kernel/task.go @@ -709,9 +709,9 @@ func (t *Task) FDTable() *FDTable { return t.fdTable } -// GetFile is a convenience wrapper t.FDTable().GetFile. +// GetFile is a convenience wrapper for t.FDTable().Get. // -// Precondition: same as FDTable. +// Precondition: same as FDTable.Get. func (t *Task) GetFile(fd int32) *fs.File { f, _ := t.fdTable.Get(fd) return f diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go index 8639d379f..bb5560acf 100644 --- a/pkg/sentry/kernel/task_context.go +++ b/pkg/sentry/kernel/task_context.go @@ -18,10 +18,8 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/cpuid" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/context" - "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel/futex" "gvisor.dev/gvisor/pkg/sentry/loader" "gvisor.dev/gvisor/pkg/sentry/mm" @@ -132,30 +130,21 @@ func (t *Task) Stack() *arch.Stack { return &arch.Stack{t.Arch(), t.MemoryManager(), usermem.Addr(t.Arch().Stack())} } -// LoadTaskImage loads filename into a new TaskContext. +// LoadTaskImage loads a specified file into a new TaskContext. // -// It takes several arguments: -// * mounts: MountNamespace to lookup filename in -// * root: Root to lookup filename under -// * wd: Working directory to lookup filename under -// * maxTraversals: maximum number of symlinks to follow -// * filename: path to binary to load -// * file: an open fs.File object of the binary to load. If set, -// file will be loaded and not filename. -// * argv: Binary argv -// * envv: Binary envv -// * fs: Binary FeatureSet -func (k *Kernel) LoadTaskImage(ctx context.Context, mounts *fs.MountNamespace, root, wd *fs.Dirent, maxTraversals *uint, filename string, file *fs.File, argv, envv []string, fs *cpuid.FeatureSet) (*TaskContext, *syserr.Error) { - // If File is not nil, we should load that instead of resolving filename. - if file != nil { - filename = file.MappedName(ctx) +// args.MemoryManager does not need to be set by the caller. +func (k *Kernel) LoadTaskImage(ctx context.Context, args loader.LoadArgs) (*TaskContext, *syserr.Error) { + // If File is not nil, we should load that instead of resolving Filename. + if args.File != nil { + args.Filename = args.File.MappedName(ctx) } // Prepare a new user address space to load into. m := mm.NewMemoryManager(k, k) defer m.DecUsers(ctx) + args.MemoryManager = m - os, ac, name, err := loader.Load(ctx, m, mounts, root, wd, maxTraversals, fs, filename, file, argv, envv, k.extraAuxv, k.vdso) + os, ac, name, err := loader.Load(ctx, args, k.extraAuxv, k.vdso) if err != nil { return nil, err } diff --git a/pkg/sentry/kernel/task_identity.go b/pkg/sentry/kernel/task_identity.go index 78ff14b20..ce3e6ef28 100644 --- a/pkg/sentry/kernel/task_identity.go +++ b/pkg/sentry/kernel/task_identity.go @@ -465,8 +465,8 @@ func (t *Task) SetKeepCaps(k bool) { // disables the features we don't support anyway, is always set. This // drastically simplifies this function. // -// - We don't implement AT_SECURE, because no_new_privs always being set means -// that the conditions that require AT_SECURE never arise. (Compare Linux's +// - We don't set AT_SECURE = 1, because no_new_privs always being set means +// that the conditions that require AT_SECURE = 1 never arise. (Compare Linux's // security/commoncap.c:cap_bprm_set_creds() and cap_bprm_secureexec().) // // - We don't check for CAP_SYS_ADMIN in prctl(PR_SET_SECCOMP), since diff --git a/pkg/sentry/kernel/task_sched.go b/pkg/sentry/kernel/task_sched.go index e76c069b0..8b148db35 100644 --- a/pkg/sentry/kernel/task_sched.go +++ b/pkg/sentry/kernel/task_sched.go @@ -126,12 +126,22 @@ func (t *Task) accountTaskGoroutineEnter(state TaskGoroutineState) { t.gosched.Timestamp = now t.gosched.State = state t.goschedSeq.EndWrite() + + if state != TaskGoroutineRunningApp { + // Task is blocking/stopping. + t.k.decRunningTasks() + } } // Preconditions: The caller must be running on the task goroutine, and leaving // a state indicated by a previous call to // t.accountTaskGoroutineEnter(state). func (t *Task) accountTaskGoroutineLeave(state TaskGoroutineState) { + if state != TaskGoroutineRunningApp { + // Task is unblocking/continuing. + t.k.incRunningTasks() + } + now := t.k.CPUClockNow() if t.gosched.State != state { panic(fmt.Sprintf("Task goroutine switching from state %v (expected %v) to %v", t.gosched.State, state, TaskGoroutineRunningSys)) @@ -330,7 +340,7 @@ func newKernelCPUClockTicker(k *Kernel) *kernelCPUClockTicker { } // Notify implements ktime.TimerListener.Notify. -func (ticker *kernelCPUClockTicker) Notify(exp uint64) { +func (ticker *kernelCPUClockTicker) Notify(exp uint64, setting ktime.Setting) (ktime.Setting, bool) { // Only increment cpuClock by 1 regardless of the number of expirations. // This approximately compensates for cases where thread throttling or bad // Go runtime scheduling prevents the kernelCPUClockTicker goroutine, and @@ -426,6 +436,27 @@ func (ticker *kernelCPUClockTicker) Notify(exp uint64) { tgs[i] = nil } ticker.tgs = tgs[:0] + + // If nothing is running, we can disable the timer. + tasks := atomic.LoadInt64(&ticker.k.runningTasks) + if tasks == 0 { + ticker.k.runningTasksMu.Lock() + defer ticker.k.runningTasksMu.Unlock() + tasks := atomic.LoadInt64(&ticker.k.runningTasks) + if tasks != 0 { + // Raced with a 0 -> 1 transition. + return setting, false + } + + // Stop the timer. We must cache the current setting so the + // kernel can access it without violating the lock order. + ticker.k.cpuClockTickerSetting = setting + ticker.k.cpuClockTickerDisabled = true + setting.Enabled = false + return setting, true + } + + return setting, false } // Destroy implements ktime.TimerListener.Destroy. diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go index 0eef24bfb..72568d296 100644 --- a/pkg/sentry/kernel/thread_group.go +++ b/pkg/sentry/kernel/thread_group.go @@ -511,8 +511,9 @@ type itimerRealListener struct { } // Notify implements ktime.TimerListener.Notify. -func (l *itimerRealListener) Notify(exp uint64) { +func (l *itimerRealListener) Notify(exp uint64, setting ktime.Setting) (ktime.Setting, bool) { l.tg.SendSignal(SignalInfoPriv(linux.SIGALRM)) + return ktime.Setting{}, false } // Destroy implements ktime.TimerListener.Destroy. diff --git a/pkg/sentry/kernel/time/BUILD b/pkg/sentry/kernel/time/BUILD index 9beae4b31..31847e1df 100644 --- a/pkg/sentry/kernel/time/BUILD +++ b/pkg/sentry/kernel/time/BUILD @@ -1,7 +1,7 @@ -package(licenses = ["notice"]) - load("//tools/go_stateify:defs.bzl", "go_library") +package(licenses = ["notice"]) + go_library( name = "time", srcs = [ diff --git a/pkg/sentry/kernel/time/time.go b/pkg/sentry/kernel/time/time.go index aa6c75d25..107394183 100644 --- a/pkg/sentry/kernel/time/time.go +++ b/pkg/sentry/kernel/time/time.go @@ -280,13 +280,16 @@ func (ClockEventsQueue) Readiness(mask waiter.EventMask) waiter.EventMask { // A TimerListener receives expirations from a Timer. type TimerListener interface { // Notify is called when its associated Timer expires. exp is the number of - // expirations. + // expirations. setting is the next timer Setting. // // Notify is called with the associated Timer's mutex locked, so Notify // must not take any locks that precede Timer.mu in lock order. // + // If Notify returns true, the timer will use the returned setting + // rather than the passed one. + // // Preconditions: exp > 0. - Notify(exp uint64) + Notify(exp uint64, setting Setting) (newSetting Setting, update bool) // Destroy is called when the timer is destroyed. Destroy() @@ -533,7 +536,9 @@ func (t *Timer) Tick() { s, exp := t.setting.At(now) t.setting = s if exp > 0 { - t.listener.Notify(exp) + if newS, ok := t.listener.Notify(exp, t.setting); ok { + t.setting = newS + } } t.resetKickerLocked(now) } @@ -588,7 +593,9 @@ func (t *Timer) Get() (Time, Setting) { s, exp := t.setting.At(now) t.setting = s if exp > 0 { - t.listener.Notify(exp) + if newS, ok := t.listener.Notify(exp, t.setting); ok { + t.setting = newS + } } t.resetKickerLocked(now) return now, s @@ -620,7 +627,9 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) { } oldS, oldExp := t.setting.At(now) if oldExp > 0 { - t.listener.Notify(oldExp) + t.listener.Notify(oldExp, oldS) + // N.B. The returned Setting doesn't matter because we're about + // to overwrite. } if f != nil { f() @@ -628,7 +637,9 @@ func (t *Timer) SwapAnd(s Setting, f func()) (Time, Setting) { newS, newExp := s.At(now) t.setting = newS if newExp > 0 { - t.listener.Notify(newExp) + if newS, ok := t.listener.Notify(newExp, t.setting); ok { + t.setting = newS + } } t.resetKickerLocked(now) return now, oldS @@ -683,11 +694,13 @@ func NewChannelNotifier() (TimerListener, <-chan struct{}) { } // Notify implements ktime.TimerListener.Notify. -func (c *ChannelNotifier) Notify(uint64) { +func (c *ChannelNotifier) Notify(uint64, Setting) (Setting, bool) { select { case c.tchan <- struct{}{}: default: } + + return Setting{}, false } // Destroy implements ktime.TimerListener.Destroy and will close the channel. |