From 55332aca95a55378957f89a10f21d9d1714070a5 Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Wed, 20 Jan 2021 16:51:59 -0800 Subject: Move Lock/UnlockPOSIX into LockFD util. PiperOrigin-RevId: 352904728 --- pkg/sentry/vfs/file_description.go | 39 +++++++++++++++++++++++----- pkg/sentry/vfs/file_description_impl_util.go | 14 ++++++++-- pkg/sentry/vfs/lock.go | 16 +++--------- 3 files changed, 49 insertions(+), 20 deletions(-) (limited to 'pkg/sentry/vfs') diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go index 5321ac80a..dbf8425b4 100644 --- a/pkg/sentry/vfs/file_description.go +++ b/pkg/sentry/vfs/file_description.go @@ -454,10 +454,10 @@ type FileDescriptionImpl interface { UnlockBSD(ctx context.Context, uid lock.UniqueID) error // LockPOSIX tries to acquire a POSIX-style advisory file lock. - LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, start, length uint64, whence int16, block lock.Blocker) error + LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, r lock.LockRange, block lock.Blocker) error // UnlockPOSIX releases a POSIX-style advisory file lock. - UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, length uint64, whence int16) error + UnlockPOSIX(ctx context.Context, uid lock.UniqueID, ComputeLockRange lock.LockRange) error } // Dirent holds the information contained in struct linux_dirent64. @@ -802,13 +802,40 @@ func (fd *FileDescription) UnlockBSD(ctx context.Context) error { } // LockPOSIX locks a POSIX-style file range lock. -func (fd *FileDescription) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, start, end uint64, whence int16, block lock.Blocker) error { - return fd.impl.LockPOSIX(ctx, uid, t, start, end, whence, block) +func (fd *FileDescription) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, r lock.LockRange, block lock.Blocker) error { + return fd.impl.LockPOSIX(ctx, uid, t, r, block) } // UnlockPOSIX unlocks a POSIX-style file range lock. -func (fd *FileDescription) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, end uint64, whence int16) error { - return fd.impl.UnlockPOSIX(ctx, uid, start, end, whence) +func (fd *FileDescription) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, r lock.LockRange) error { + return fd.impl.UnlockPOSIX(ctx, uid, r) +} + +// ComputeLockRange computes the range of a file lock based on the given values. +func (fd *FileDescription) ComputeLockRange(ctx context.Context, start uint64, length uint64, whence int16) (lock.LockRange, error) { + var off int64 + switch whence { + case linux.SEEK_SET: + off = 0 + case linux.SEEK_CUR: + // Note that Linux does not hold any mutexes while retrieving the file + // offset, see fs/locks.c:flock_to_posix_lock and fs/locks.c:fcntl_setlk. + curOff, err := fd.Seek(ctx, 0, linux.SEEK_CUR) + if err != nil { + return lock.LockRange{}, err + } + off = curOff + case linux.SEEK_END: + stat, err := fd.Stat(ctx, StatOptions{Mask: linux.STATX_SIZE}) + if err != nil { + return lock.LockRange{}, err + } + off = int64(stat.Size) + default: + return lock.LockRange{}, syserror.EINVAL + } + + return lock.ComputeRange(int64(start), int64(length), off) } // A FileAsync sends signals to its owner when w is ready for IO. This is only diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go index 48ca9de44..9d13e2ccb 100644 --- a/pkg/sentry/vfs/file_description_impl_util.go +++ b/pkg/sentry/vfs/file_description_impl_util.go @@ -429,6 +429,16 @@ func (fd *LockFD) UnlockBSD(ctx context.Context, uid fslock.UniqueID) error { return nil } +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *LockFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, r fslock.LockRange, block fslock.Blocker) error { + return fd.locks.LockPOSIX(ctx, uid, t, r, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *LockFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, r fslock.LockRange) error { + return fd.locks.UnlockPOSIX(ctx, uid, r) +} + // NoLockFD implements Lock*/Unlock* portion of FileDescriptionImpl interface // returning ENOLCK. // @@ -446,11 +456,11 @@ func (NoLockFD) UnlockBSD(ctx context.Context, uid fslock.UniqueID) error { } // LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. -func (NoLockFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { +func (NoLockFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, r fslock.LockRange, block fslock.Blocker) error { return syserror.ENOLCK } // UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. -func (NoLockFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { +func (NoLockFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, r fslock.LockRange) error { return syserror.ENOLCK } diff --git a/pkg/sentry/vfs/lock.go b/pkg/sentry/vfs/lock.go index 1ff202f2a..bcff35792 100644 --- a/pkg/sentry/vfs/lock.go +++ b/pkg/sentry/vfs/lock.go @@ -61,12 +61,8 @@ func (fl *FileLocks) UnlockBSD(uid fslock.UniqueID) { } // LockPOSIX tries to acquire a POSIX-style lock on a file region. -func (fl *FileLocks) LockPOSIX(ctx context.Context, fd *FileDescription, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { - rng, err := computeRange(ctx, fd, start, length, whence) - if err != nil { - return err - } - if fl.posix.LockRegion(uid, t, rng, block) { +func (fl *FileLocks) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, r fslock.LockRange, block fslock.Blocker) error { + if fl.posix.LockRegion(uid, t, r, block) { return nil } @@ -82,12 +78,8 @@ func (fl *FileLocks) LockPOSIX(ctx context.Context, fd *FileDescription, uid fsl // // This operation is always successful, even if there did not exist a lock on // the requested region held by uid in the first place. -func (fl *FileLocks) UnlockPOSIX(ctx context.Context, fd *FileDescription, uid fslock.UniqueID, start, length uint64, whence int16) error { - rng, err := computeRange(ctx, fd, start, length, whence) - if err != nil { - return err - } - fl.posix.UnlockRegion(uid, rng) +func (fl *FileLocks) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, r fslock.LockRange) error { + fl.posix.UnlockRegion(uid, r) return nil } -- cgit v1.2.3