From 67565078bbcdd8f797206d996605df8f6658d00a Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Tue, 9 Jun 2020 18:44:57 -0700
Subject: Implement flock(2) in VFS2

LockFD is the generic implementation that can be embedded in
FileDescriptionImpl implementations. Unique lock ID is
maintained in vfs.FileDescription and is created on demand.

Updates #1480

PiperOrigin-RevId: 315604825
---
 pkg/sentry/fsimpl/host/host.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'pkg/sentry/fsimpl/host/host.go')

diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 18b127521..5ec5100b8 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -34,6 +34,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	unixsocket "gvisor.dev/gvisor/pkg/sentry/socket/unix"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sentry/vfs/lock"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
@@ -182,6 +183,8 @@ type inode struct {
 	kernfs.InodeNotDirectory
 	kernfs.InodeNotSymlink
 
+	locks lock.FileLocks
+
 	// When the reference count reaches zero, the host fd is closed.
 	refs.AtomicRefCount
 
@@ -468,7 +471,7 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u
 			return nil, err
 		}
 		// Currently, we only allow Unix sockets to be imported.
-		return unixsocket.NewFileDescription(ep, ep.Type(), flags, mnt, d)
+		return unixsocket.NewFileDescription(ep, ep.Type(), flags, mnt, d, &i.locks)
 	}
 
 	// TODO(gvisor.dev/issue/1672): Whitelist specific file types here, so that
@@ -478,6 +481,7 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u
 			fileDescription: fileDescription{inode: i},
 			termios:         linux.DefaultSlaveTermios,
 		}
+		fd.LockFD.Init(&i.locks)
 		vfsfd := &fd.vfsfd
 		if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil {
 			return nil, err
@@ -486,6 +490,7 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u
 	}
 
 	fd := &fileDescription{inode: i}
+	fd.LockFD.Init(&i.locks)
 	vfsfd := &fd.vfsfd
 	if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil {
 		return nil, err
@@ -497,6 +502,7 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
+	vfs.LockFD
 
 	// inode is vfsfd.Dentry().Impl().(*kernfs.Dentry).Inode().(*inode), but
 	// cached to reduce indirections and casting. fileDescription does not hold
-- 
cgit v1.2.3