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-rw-r--r--pkg/sentry/fs/BUILD4
-rw-r--r--pkg/sentry/fs/dirent.go4
-rw-r--r--pkg/sentry/fs/dirent_refs_test.go2
-rw-r--r--pkg/sentry/fs/fdpipe/BUILD4
-rw-r--r--pkg/sentry/fs/file.go23
-rw-r--r--pkg/sentry/fs/file_operations.go9
-rw-r--r--pkg/sentry/fs/file_overlay.go9
-rw-r--r--pkg/sentry/fs/fsutil/BUILD4
-rw-r--r--pkg/sentry/fs/fsutil/file.go6
-rw-r--r--pkg/sentry/fs/gofer/BUILD4
-rw-r--r--pkg/sentry/fs/host/BUILD4
-rw-r--r--pkg/sentry/fs/inotify.go5
-rw-r--r--pkg/sentry/fs/lock/BUILD4
-rw-r--r--pkg/sentry/fs/proc/BUILD4
-rw-r--r--pkg/sentry/fs/proc/seqfile/BUILD4
-rw-r--r--pkg/sentry/fs/ramfs/BUILD4
-rw-r--r--pkg/sentry/fs/splice.go162
-rw-r--r--pkg/sentry/fs/tmpfs/BUILD4
-rw-r--r--pkg/sentry/fs/tty/BUILD5
-rw-r--r--pkg/sentry/fs/tty/dir.go3
-rw-r--r--pkg/sentry/fs/tty/master.go17
-rw-r--r--pkg/sentry/fs/tty/slave.go13
-rw-r--r--pkg/sentry/fs/tty/terminal.go92
23 files changed, 267 insertions, 123 deletions
diff --git a/pkg/sentry/fs/BUILD b/pkg/sentry/fs/BUILD
index d7259b47b..3119a61b6 100644
--- a/pkg/sentry/fs/BUILD
+++ b/pkg/sentry/fs/BUILD
@@ -1,7 +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", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "fs",
diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go
index fbca06761..3cb73bd78 100644
--- a/pkg/sentry/fs/dirent.go
+++ b/pkg/sentry/fs/dirent.go
@@ -1126,7 +1126,7 @@ func (d *Dirent) unmount(ctx context.Context, replacement *Dirent) error {
// Remove removes the given file or symlink. The root dirent is used to
// resolve name, and must not be nil.
-func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string) error {
+func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string, dirPath bool) error {
// Check the root.
if root == nil {
panic("Dirent.Remove: root must not be nil")
@@ -1151,6 +1151,8 @@ func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string) error {
// Remove cannot remove directories.
if IsDir(child.Inode.StableAttr) {
return syscall.EISDIR
+ } else if dirPath {
+ return syscall.ENOTDIR
}
// Remove cannot remove a mount point.
diff --git a/pkg/sentry/fs/dirent_refs_test.go b/pkg/sentry/fs/dirent_refs_test.go
index 884e3ff06..47bc72a88 100644
--- a/pkg/sentry/fs/dirent_refs_test.go
+++ b/pkg/sentry/fs/dirent_refs_test.go
@@ -343,7 +343,7 @@ func TestRemoveExtraRefs(t *testing.T) {
}
d := f.Dirent
- if err := test.root.Remove(contexttest.Context(t), test.root, name); err != nil {
+ if err := test.root.Remove(contexttest.Context(t), test.root, name, false /* dirPath */); err != nil {
t.Fatalf("root.Remove(root, %q) failed: %v", name, err)
}
diff --git a/pkg/sentry/fs/fdpipe/BUILD b/pkg/sentry/fs/fdpipe/BUILD
index bf00b9c09..b9bd9ed17 100644
--- a/pkg/sentry/fs/fdpipe/BUILD
+++ b/pkg/sentry/fs/fdpipe/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "fdpipe",
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index bb8117f89..c0a6e884b 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -515,6 +515,11 @@ type lockedReader struct {
// File is the file to read from.
File *File
+
+ // Offset is the offset to start at.
+ //
+ // This applies only to Read, not ReadAt.
+ Offset int64
}
// Read implements io.Reader.Read.
@@ -522,7 +527,8 @@ func (r *lockedReader) Read(buf []byte) (int, error) {
if r.Ctx.Interrupted() {
return 0, syserror.ErrInterrupted
}
- n, err := r.File.FileOperations.Read(r.Ctx, r.File, usermem.BytesIOSequence(buf), r.File.offset)
+ n, err := r.File.FileOperations.Read(r.Ctx, r.File, usermem.BytesIOSequence(buf), r.Offset)
+ r.Offset += n
return int(n), err
}
@@ -544,11 +550,21 @@ type lockedWriter struct {
// File is the file to write to.
File *File
+
+ // Offset is the offset to start at.
+ //
+ // This applies only to Write, not WriteAt.
+ Offset int64
}
// Write implements io.Writer.Write.
func (w *lockedWriter) Write(buf []byte) (int, error) {
- return w.WriteAt(buf, w.File.offset)
+ if w.Ctx.Interrupted() {
+ return 0, syserror.ErrInterrupted
+ }
+ n, err := w.WriteAt(buf, w.Offset)
+ w.Offset += int64(n)
+ return int(n), err
}
// WriteAt implements io.Writer.WriteAt.
@@ -562,6 +578,9 @@ func (w *lockedWriter) WriteAt(buf []byte, offset int64) (int, error) {
// io.Copy, since our own Write interface does not have this same
// contract. Enforce that here.
for written < len(buf) {
+ if w.Ctx.Interrupted() {
+ return written, syserror.ErrInterrupted
+ }
var n int64
n, err = w.File.FileOperations.Write(w.Ctx, w.File, usermem.BytesIOSequence(buf[written:]), offset+int64(written))
if n > 0 {
diff --git a/pkg/sentry/fs/file_operations.go b/pkg/sentry/fs/file_operations.go
index d86f5bf45..b88303f17 100644
--- a/pkg/sentry/fs/file_operations.go
+++ b/pkg/sentry/fs/file_operations.go
@@ -15,6 +15,8 @@
package fs
import (
+ "io"
+
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/memmap"
@@ -105,8 +107,11 @@ type FileOperations interface {
// on the destination, following by a buffered copy with standard Read
// and Write operations.
//
+ // If dup is set, the data should be duplicated into the destination
+ // and retained.
+ //
// The same preconditions as Read apply.
- WriteTo(ctx context.Context, file *File, dst *File, opts SpliceOpts) (int64, error)
+ WriteTo(ctx context.Context, file *File, dst io.Writer, count int64, dup bool) (int64, error)
// Write writes src to file at offset and returns the number of bytes
// written which must be greater than or equal to 0. Like Read, file
@@ -126,7 +131,7 @@ type FileOperations interface {
// source. See WriteTo for details regarding how this is called.
//
// The same preconditions as Write apply; FileFlags.Write must be set.
- ReadFrom(ctx context.Context, file *File, src *File, opts SpliceOpts) (int64, error)
+ ReadFrom(ctx context.Context, file *File, src io.Reader, count int64) (int64, error)
// Fsync writes buffered modifications of file and/or flushes in-flight
// operations to backing storage based on syncType. The range to sync is
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go
index 9820f0b13..225e40186 100644
--- a/pkg/sentry/fs/file_overlay.go
+++ b/pkg/sentry/fs/file_overlay.go
@@ -15,6 +15,7 @@
package fs
import (
+ "io"
"sync"
"gvisor.dev/gvisor/pkg/refs"
@@ -268,9 +269,9 @@ func (f *overlayFileOperations) Read(ctx context.Context, file *File, dst userme
}
// WriteTo implements FileOperations.WriteTo.
-func (f *overlayFileOperations) WriteTo(ctx context.Context, file *File, dst *File, opts SpliceOpts) (n int64, err error) {
+func (f *overlayFileOperations) WriteTo(ctx context.Context, file *File, dst io.Writer, count int64, dup bool) (n int64, err error) {
err = f.onTop(ctx, file, func(file *File, ops FileOperations) error {
- n, err = ops.WriteTo(ctx, file, dst, opts)
+ n, err = ops.WriteTo(ctx, file, dst, count, dup)
return err // Will overwrite itself.
})
return
@@ -285,9 +286,9 @@ func (f *overlayFileOperations) Write(ctx context.Context, file *File, src userm
}
// ReadFrom implements FileOperations.ReadFrom.
-func (f *overlayFileOperations) ReadFrom(ctx context.Context, file *File, src *File, opts SpliceOpts) (n int64, err error) {
+func (f *overlayFileOperations) ReadFrom(ctx context.Context, file *File, src io.Reader, count int64) (n int64, err error) {
// See above; f.upper must be non-nil.
- return f.upper.FileOperations.ReadFrom(ctx, f.upper, src, opts)
+ return f.upper.FileOperations.ReadFrom(ctx, f.upper, src, count)
}
// Fsync implements FileOperations.Fsync.
diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD
index 6499f87ac..b4ac83dc4 100644
--- a/pkg/sentry/fs/fsutil/BUILD
+++ b/pkg/sentry/fs/fsutil/BUILD
@@ -1,7 +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", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_template_instance(
name = "dirty_set_impl",
diff --git a/pkg/sentry/fs/fsutil/file.go b/pkg/sentry/fs/fsutil/file.go
index 626b9126a..fc5b3b1a1 100644
--- a/pkg/sentry/fs/fsutil/file.go
+++ b/pkg/sentry/fs/fsutil/file.go
@@ -15,6 +15,8 @@
package fsutil
import (
+ "io"
+
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -228,12 +230,12 @@ func (FileNoIoctl) Ioctl(context.Context, *fs.File, usermem.IO, arch.SyscallArgu
type FileNoSplice struct{}
// WriteTo implements fs.FileOperations.WriteTo.
-func (FileNoSplice) WriteTo(context.Context, *fs.File, *fs.File, fs.SpliceOpts) (int64, error) {
+func (FileNoSplice) WriteTo(context.Context, *fs.File, io.Writer, int64, bool) (int64, error) {
return 0, syserror.ENOSYS
}
// ReadFrom implements fs.FileOperations.ReadFrom.
-func (FileNoSplice) ReadFrom(context.Context, *fs.File, *fs.File, fs.SpliceOpts) (int64, error) {
+func (FileNoSplice) ReadFrom(context.Context, *fs.File, io.Reader, int64) (int64, error) {
return 0, syserror.ENOSYS
}
diff --git a/pkg/sentry/fs/gofer/BUILD b/pkg/sentry/fs/gofer/BUILD
index 6b993928c..2b71ca0e1 100644
--- a/pkg/sentry/fs/gofer/BUILD
+++ b/pkg/sentry/fs/gofer/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "gofer",
diff --git a/pkg/sentry/fs/host/BUILD b/pkg/sentry/fs/host/BUILD
index b1080fb1a..3e532332e 100644
--- a/pkg/sentry/fs/host/BUILD
+++ b/pkg/sentry/fs/host/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "host",
diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go
index c7f4e2d13..ba3e0233d 100644
--- a/pkg/sentry/fs/inotify.go
+++ b/pkg/sentry/fs/inotify.go
@@ -15,6 +15,7 @@
package fs
import (
+ "io"
"sync"
"sync/atomic"
@@ -172,7 +173,7 @@ func (i *Inotify) Read(ctx context.Context, _ *File, dst usermem.IOSequence, _ i
}
// WriteTo implements FileOperations.WriteTo.
-func (*Inotify) WriteTo(context.Context, *File, *File, SpliceOpts) (int64, error) {
+func (*Inotify) WriteTo(context.Context, *File, io.Writer, int64, bool) (int64, error) {
return 0, syserror.ENOSYS
}
@@ -182,7 +183,7 @@ func (*Inotify) Fsync(context.Context, *File, int64, int64, SyncType) error {
}
// ReadFrom implements FileOperations.ReadFrom.
-func (*Inotify) ReadFrom(context.Context, *File, *File, SpliceOpts) (int64, error) {
+func (*Inotify) ReadFrom(context.Context, *File, io.Reader, int64) (int64, error) {
return 0, syserror.ENOSYS
}
diff --git a/pkg/sentry/fs/lock/BUILD b/pkg/sentry/fs/lock/BUILD
index 08d7c0c57..5a7a5b8cd 100644
--- a/pkg/sentry/fs/lock/BUILD
+++ b/pkg/sentry/fs/lock/BUILD
@@ -1,7 +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", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_template_instance(
name = "lock_range",
diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD
index c7599d1f6..1c93e8886 100644
--- a/pkg/sentry/fs/proc/BUILD
+++ b/pkg/sentry/fs/proc/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "proc",
diff --git a/pkg/sentry/fs/proc/seqfile/BUILD b/pkg/sentry/fs/proc/seqfile/BUILD
index 20c3eefc8..76433c7d0 100644
--- a/pkg/sentry/fs/proc/seqfile/BUILD
+++ b/pkg/sentry/fs/proc/seqfile/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "seqfile",
diff --git a/pkg/sentry/fs/ramfs/BUILD b/pkg/sentry/fs/ramfs/BUILD
index 516efcc4c..d0f351e5a 100644
--- a/pkg/sentry/fs/ramfs/BUILD
+++ b/pkg/sentry/fs/ramfs/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "ramfs",
diff --git a/pkg/sentry/fs/splice.go b/pkg/sentry/fs/splice.go
index eed1c2854..b03b7f836 100644
--- a/pkg/sentry/fs/splice.go
+++ b/pkg/sentry/fs/splice.go
@@ -18,7 +18,6 @@ import (
"io"
"sync/atomic"
- "gvisor.dev/gvisor/pkg/secio"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/syserror"
)
@@ -33,146 +32,131 @@ func Splice(ctx context.Context, dst *File, src *File, opts SpliceOpts) (int64,
}
// Check whether or not the objects being sliced are stream-oriented
- // (i.e. pipes or sockets). If yes, we elide checks and offset locks.
- srcPipe := IsPipe(src.Dirent.Inode.StableAttr) || IsSocket(src.Dirent.Inode.StableAttr)
- dstPipe := IsPipe(dst.Dirent.Inode.StableAttr) || IsSocket(dst.Dirent.Inode.StableAttr)
+ // (i.e. pipes or sockets). For all stream-oriented files and files
+ // where a specific offiset is not request, we acquire the file mutex.
+ // This has two important side effects. First, it provides the standard
+ // protection against concurrent writes that would mutate the offset.
+ // Second, it prevents Splice deadlocks. Only internal anonymous files
+ // implement the ReadFrom and WriteTo methods directly, and since such
+ // anonymous files are referred to by a unique fs.File object, we know
+ // that the file mutex takes strict precedence over internal locks.
+ // Since we enforce lock ordering here, we can't deadlock by using
+ // using a file in two different splice operations simultaneously.
+ srcPipe := !IsRegular(src.Dirent.Inode.StableAttr)
+ dstPipe := !IsRegular(dst.Dirent.Inode.StableAttr)
+ dstAppend := !dstPipe && dst.Flags().Append
+ srcLock := srcPipe || !opts.SrcOffset
+ dstLock := dstPipe || !opts.DstOffset || dstAppend
- if !dstPipe && !opts.DstOffset && !srcPipe && !opts.SrcOffset {
+ switch {
+ case srcLock && dstLock:
switch {
case dst.UniqueID < src.UniqueID:
// Acquire dst first.
if !dst.mu.Lock(ctx) {
return 0, syserror.ErrInterrupted
}
- defer dst.mu.Unlock()
if !src.mu.Lock(ctx) {
+ dst.mu.Unlock()
return 0, syserror.ErrInterrupted
}
- defer src.mu.Unlock()
case dst.UniqueID > src.UniqueID:
// Acquire src first.
if !src.mu.Lock(ctx) {
return 0, syserror.ErrInterrupted
}
- defer src.mu.Unlock()
if !dst.mu.Lock(ctx) {
+ src.mu.Unlock()
return 0, syserror.ErrInterrupted
}
- defer dst.mu.Unlock()
case dst.UniqueID == src.UniqueID:
// Acquire only one lock; it's the same file. This is a
// bit of a edge case, but presumably it's possible.
if !dst.mu.Lock(ctx) {
return 0, syserror.ErrInterrupted
}
- defer dst.mu.Unlock()
+ srcLock = false // Only need one unlock.
}
// Use both offsets (locked).
opts.DstStart = dst.offset
opts.SrcStart = src.offset
- } else if !dstPipe && !opts.DstOffset {
+ case dstLock:
// Acquire only dst.
if !dst.mu.Lock(ctx) {
return 0, syserror.ErrInterrupted
}
- defer dst.mu.Unlock()
opts.DstStart = dst.offset // Safe: locked.
- } else if !srcPipe && !opts.SrcOffset {
+ case srcLock:
// Acquire only src.
if !src.mu.Lock(ctx) {
return 0, syserror.ErrInterrupted
}
- defer src.mu.Unlock()
opts.SrcStart = src.offset // Safe: locked.
}
- // Check append-only mode and the limit.
- if !dstPipe {
+ var err error
+ if dstAppend {
unlock := dst.Dirent.Inode.lockAppendMu(dst.Flags().Append)
defer unlock()
- if dst.Flags().Append {
- if opts.DstOffset {
- // We need to acquire the lock.
- if !dst.mu.Lock(ctx) {
- return 0, syserror.ErrInterrupted
- }
- defer dst.mu.Unlock()
- }
- // Figure out the appropriate offset to use.
- if err := dst.offsetForAppend(ctx, &opts.DstStart); err != nil {
- return 0, err
- }
- }
+ // Figure out the appropriate offset to use.
+ err = dst.offsetForAppend(ctx, &opts.DstStart)
+ }
+ if err == nil && !dstPipe {
// Enforce file limits.
limit, ok := dst.checkLimit(ctx, opts.DstStart)
switch {
case ok && limit == 0:
- return 0, syserror.ErrExceedsFileSizeLimit
+ err = syserror.ErrExceedsFileSizeLimit
case ok && limit < opts.Length:
opts.Length = limit // Cap the write.
}
}
+ if err != nil {
+ if dstLock {
+ dst.mu.Unlock()
+ }
+ if srcLock {
+ src.mu.Unlock()
+ }
+ return 0, err
+ }
- // Attempt to do a WriteTo; this is likely the most efficient.
- //
- // The underlying implementation may be able to donate buffers.
- newOpts := SpliceOpts{
- Length: opts.Length,
- SrcStart: opts.SrcStart,
- SrcOffset: !srcPipe,
- Dup: opts.Dup,
- DstStart: opts.DstStart,
- DstOffset: !dstPipe,
+ // Construct readers and writers for the splice. This is used to
+ // provide a safer locking path for the WriteTo/ReadFrom operations
+ // (since they will otherwise go through public interface methods which
+ // conflict with locking done above), and simplifies the fallback path.
+ w := &lockedWriter{
+ Ctx: ctx,
+ File: dst,
+ Offset: opts.DstStart,
}
- n, err := src.FileOperations.WriteTo(ctx, src, dst, newOpts)
- if n == 0 && err != nil {
- // Attempt as a ReadFrom. If a WriteTo, a ReadFrom may also
- // be more efficient than a copy if buffers are cached or readily
- // available. (It's unlikely that they can actually be donate
- n, err = dst.FileOperations.ReadFrom(ctx, dst, src, newOpts)
+ r := &lockedReader{
+ Ctx: ctx,
+ File: src,
+ Offset: opts.SrcStart,
}
- if n == 0 && err != nil {
- // If we've failed up to here, and at least one of the sources
- // is a pipe or socket, then we can't properly support dup.
- // Return an error indicating that this operation is not
- // supported.
- if (srcPipe || dstPipe) && newOpts.Dup {
- return 0, syserror.EINVAL
- }
- // We failed to splice the files. But that's fine; we just fall
- // back to a slow path in this case. This copies without doing
- // any mode changes, so should still be more efficient.
- var (
- r io.Reader
- w io.Writer
- )
- fw := &lockedWriter{
- Ctx: ctx,
- File: dst,
- }
- if newOpts.DstOffset {
- // Use the provided offset.
- w = secio.NewOffsetWriter(fw, newOpts.DstStart)
- } else {
- // Writes will proceed with no offset.
- w = fw
- }
- fr := &lockedReader{
- Ctx: ctx,
- File: src,
- }
- if newOpts.SrcOffset {
- // Limit to the given offset and length.
- r = io.NewSectionReader(fr, opts.SrcStart, opts.Length)
- } else {
- // Limit just to the given length.
- r = &io.LimitedReader{fr, opts.Length}
- }
+ // Attempt to do a WriteTo; this is likely the most efficient.
+ n, err := src.FileOperations.WriteTo(ctx, src, w, opts.Length, opts.Dup)
+ if n == 0 && err != nil && err != syserror.ErrWouldBlock && !opts.Dup {
+ // Attempt as a ReadFrom. If a WriteTo, a ReadFrom may also be
+ // more efficient than a copy if buffers are cached or readily
+ // available. (It's unlikely that they can actually be donated).
+ n, err = dst.FileOperations.ReadFrom(ctx, dst, r, opts.Length)
+ }
- // Copy between the two.
- n, err = io.Copy(w, r)
+ // Support one last fallback option, but only if at least one of
+ // the source and destination are regular files. This is because
+ // if we block at some point, we could lose data. If the source is
+ // not a pipe then reading is not destructive; if the destination
+ // is a regular file, then it is guaranteed not to block writing.
+ if n == 0 && err != nil && err != syserror.ErrWouldBlock && !opts.Dup && (!dstPipe || !srcPipe) {
+ // Fallback to an in-kernel copy.
+ n, err = io.Copy(w, &io.LimitedReader{
+ R: r,
+ N: opts.Length,
+ })
}
// Update offsets, if required.
@@ -185,5 +169,13 @@ func Splice(ctx context.Context, dst *File, src *File, opts SpliceOpts) (int64,
}
}
+ // Drop locks.
+ if dstLock {
+ dst.mu.Unlock()
+ }
+ if srcLock {
+ src.mu.Unlock()
+ }
+
return n, err
}
diff --git a/pkg/sentry/fs/tmpfs/BUILD b/pkg/sentry/fs/tmpfs/BUILD
index 8f7eb5757..11b680929 100644
--- a/pkg/sentry/fs/tmpfs/BUILD
+++ b/pkg/sentry/fs/tmpfs/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "tmpfs",
diff --git a/pkg/sentry/fs/tty/BUILD b/pkg/sentry/fs/tty/BUILD
index 5e9327aec..25811f668 100644
--- a/pkg/sentry/fs/tty/BUILD
+++ b/pkg/sentry/fs/tty/BUILD
@@ -1,6 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
package(licenses = ["notice"])
-load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_stateify:defs.bzl", "go_library")
go_library(
name = "tty",
@@ -23,6 +25,7 @@ go_library(
"//pkg/sentry/device",
"//pkg/sentry/fs",
"//pkg/sentry/fs/fsutil",
+ "//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/safemem",
"//pkg/sentry/socket/unix/transport",
diff --git a/pkg/sentry/fs/tty/dir.go b/pkg/sentry/fs/tty/dir.go
index 1d128532b..2f639c823 100644
--- a/pkg/sentry/fs/tty/dir.go
+++ b/pkg/sentry/fs/tty/dir.go
@@ -129,6 +129,9 @@ func newDir(ctx context.Context, m *fs.MountSource) *fs.Inode {
// Release implements fs.InodeOperations.Release.
func (d *dirInodeOperations) Release(ctx context.Context) {
+ d.mu.Lock()
+ defer d.mu.Unlock()
+
d.master.DecRef()
if len(d.slaves) != 0 {
panic(fmt.Sprintf("devpts directory still contains active terminals: %+v", d))
diff --git a/pkg/sentry/fs/tty/master.go b/pkg/sentry/fs/tty/master.go
index 92ec1ca18..19b7557d5 100644
--- a/pkg/sentry/fs/tty/master.go
+++ b/pkg/sentry/fs/tty/master.go
@@ -172,6 +172,19 @@ func (mf *masterFileOperations) Ioctl(ctx context.Context, _ *fs.File, io userme
return 0, mf.t.ld.windowSize(ctx, io, args)
case linux.TIOCSWINSZ:
return 0, mf.t.ld.setWindowSize(ctx, io, args)
+ case linux.TIOCSCTTY:
+ // Make the given terminal the controlling terminal of the
+ // calling process.
+ return 0, mf.t.setControllingTTY(ctx, io, args, true /* isMaster */)
+ case linux.TIOCNOTTY:
+ // Release this process's controlling terminal.
+ return 0, mf.t.releaseControllingTTY(ctx, io, args, true /* isMaster */)
+ case linux.TIOCGPGRP:
+ // Get the foreground process group.
+ return mf.t.foregroundProcessGroup(ctx, io, args, true /* isMaster */)
+ case linux.TIOCSPGRP:
+ // Set the foreground process group.
+ return mf.t.setForegroundProcessGroup(ctx, io, args, true /* isMaster */)
default:
maybeEmitUnimplementedEvent(ctx, cmd)
return 0, syserror.ENOTTY
@@ -185,8 +198,6 @@ func maybeEmitUnimplementedEvent(ctx context.Context, cmd uint32) {
linux.TCSETS,
linux.TCSETSW,
linux.TCSETSF,
- linux.TIOCGPGRP,
- linux.TIOCSPGRP,
linux.TIOCGWINSZ,
linux.TIOCSWINSZ,
linux.TIOCSETD,
@@ -200,8 +211,6 @@ func maybeEmitUnimplementedEvent(ctx context.Context, cmd uint32) {
linux.TIOCEXCL,
linux.TIOCNXCL,
linux.TIOCGEXCL,
- linux.TIOCNOTTY,
- linux.TIOCSCTTY,
linux.TIOCGSID,
linux.TIOCGETD,
linux.TIOCVHANGUP,
diff --git a/pkg/sentry/fs/tty/slave.go b/pkg/sentry/fs/tty/slave.go
index e30266404..944c4ada1 100644
--- a/pkg/sentry/fs/tty/slave.go
+++ b/pkg/sentry/fs/tty/slave.go
@@ -152,9 +152,16 @@ func (sf *slaveFileOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem
case linux.TIOCSCTTY:
// Make the given terminal the controlling terminal of the
// calling process.
- // TODO(b/129283598): Implement once we have support for job
- // control.
- return 0, nil
+ return 0, sf.si.t.setControllingTTY(ctx, io, args, false /* isMaster */)
+ case linux.TIOCNOTTY:
+ // Release this process's controlling terminal.
+ return 0, sf.si.t.releaseControllingTTY(ctx, io, args, false /* isMaster */)
+ case linux.TIOCGPGRP:
+ // Get the foreground process group.
+ return sf.si.t.foregroundProcessGroup(ctx, io, args, false /* isMaster */)
+ case linux.TIOCSPGRP:
+ // Set the foreground process group.
+ return sf.si.t.setForegroundProcessGroup(ctx, io, args, false /* isMaster */)
default:
maybeEmitUnimplementedEvent(ctx, cmd)
return 0, syserror.ENOTTY
diff --git a/pkg/sentry/fs/tty/terminal.go b/pkg/sentry/fs/tty/terminal.go
index b7cecb2ed..ff8138820 100644
--- a/pkg/sentry/fs/tty/terminal.go
+++ b/pkg/sentry/fs/tty/terminal.go
@@ -17,7 +17,10 @@ package tty
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/refs"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/usermem"
)
// Terminal is a pseudoterminal.
@@ -26,23 +29,100 @@ import (
type Terminal struct {
refs.AtomicRefCount
- // n is the terminal index.
+ // n is the terminal index. It is immutable.
n uint32
- // d is the containing directory.
+ // d is the containing directory. It is immutable.
d *dirInodeOperations
- // ld is the line discipline of the terminal.
+ // ld is the line discipline of the terminal. It is immutable.
ld *lineDiscipline
+
+ // masterKTTY contains the controlling process of the master end of
+ // this terminal. This field is immutable.
+ masterKTTY *kernel.TTY
+
+ // slaveKTTY contains the controlling process of the slave end of this
+ // terminal. This field is immutable.
+ slaveKTTY *kernel.TTY
}
func newTerminal(ctx context.Context, d *dirInodeOperations, n uint32) *Terminal {
termios := linux.DefaultSlaveTermios
t := Terminal{
- d: d,
- n: n,
- ld: newLineDiscipline(termios),
+ d: d,
+ n: n,
+ ld: newLineDiscipline(termios),
+ masterKTTY: &kernel.TTY{},
+ slaveKTTY: &kernel.TTY{},
}
t.EnableLeakCheck("tty.Terminal")
return &t
}
+
+// setControllingTTY makes tm the controlling terminal of the calling thread
+// group.
+func (tm *Terminal) setControllingTTY(ctx context.Context, io usermem.IO, args arch.SyscallArguments, isMaster bool) error {
+ task := kernel.TaskFromContext(ctx)
+ if task == nil {
+ panic("setControllingTTY must be called from a task context")
+ }
+
+ return task.ThreadGroup().SetControllingTTY(tm.tty(isMaster), args[2].Int())
+}
+
+// releaseControllingTTY removes tm as the controlling terminal of the calling
+// thread group.
+func (tm *Terminal) releaseControllingTTY(ctx context.Context, io usermem.IO, args arch.SyscallArguments, isMaster bool) error {
+ task := kernel.TaskFromContext(ctx)
+ if task == nil {
+ panic("releaseControllingTTY must be called from a task context")
+ }
+
+ return task.ThreadGroup().ReleaseControllingTTY(tm.tty(isMaster))
+}
+
+// foregroundProcessGroup gets the process group ID of tm's foreground process.
+func (tm *Terminal) foregroundProcessGroup(ctx context.Context, io usermem.IO, args arch.SyscallArguments, isMaster bool) (uintptr, error) {
+ task := kernel.TaskFromContext(ctx)
+ if task == nil {
+ panic("foregroundProcessGroup must be called from a task context")
+ }
+
+ ret, err := task.ThreadGroup().ForegroundProcessGroup(tm.tty(isMaster))
+ if err != nil {
+ return 0, err
+ }
+
+ // Write it out to *arg.
+ _, err = usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(ret), usermem.IOOpts{
+ AddressSpaceActive: true,
+ })
+ return 0, err
+}
+
+// foregroundProcessGroup sets tm's foreground process.
+func (tm *Terminal) setForegroundProcessGroup(ctx context.Context, io usermem.IO, args arch.SyscallArguments, isMaster bool) (uintptr, error) {
+ task := kernel.TaskFromContext(ctx)
+ if task == nil {
+ panic("setForegroundProcessGroup must be called from a task context")
+ }
+
+ // Read in the process group ID.
+ var pgid int32
+ if _, err := usermem.CopyObjectIn(ctx, io, args[2].Pointer(), &pgid, usermem.IOOpts{
+ AddressSpaceActive: true,
+ }); err != nil {
+ return 0, err
+ }
+
+ ret, err := task.ThreadGroup().SetForegroundProcessGroup(tm.tty(isMaster), kernel.ProcessGroupID(pgid))
+ return uintptr(ret), err
+}
+
+func (tm *Terminal) tty(isMaster bool) *kernel.TTY {
+ if isMaster {
+ return tm.masterKTTY
+ }
+ return tm.slaveKTTY
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-26 00:13:52 +0000