diff options
author | Jamie Liu <jamieliu@google.com> | 2019-11-06 17:10:30 -0800 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2019-11-06 17:11:58 -0800 |
commit | f8ffadddb39e132605f0ef3e3d39e5d7ad6e0ecf (patch) | |
tree | dd66085f179f7702dacaa7686e7b80fdfa4a5ede /runsc | |
parent | e63db5e7bbf8decc6f799965f54fcf7aa6673527 (diff) |
Add p9.OpenTruncate.
This is required to implement O_TRUNC correctly on filesystems backed by
gofers.
9P2000.L: "lopen prepares fid for file I/O. flags contains Linux open(2) flags
bits, e.g. O_RDONLY, O_RDWR, O_WRONLY."
open(2): "The argument flags must include one of the following access modes:
O_RDONLY, O_WRONLY, or O_RDWR. ... In addition, zero or more file creation
flags and file status flags can be bitwise-or'd in flags."
The reference 9P2000.L implementation also appears to expect arbitrary flags,
not just access modes, in Tlopen.flags:
https://github.com/chaos/diod/blob/master/diod/ops.c#L703
PiperOrigin-RevId: 278972683
Diffstat (limited to 'runsc')
-rw-r--r-- | runsc/fsgofer/fsgofer.go | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go index 18b853e2e..9117d9616 100644 --- a/runsc/fsgofer/fsgofer.go +++ b/runsc/fsgofer/fsgofer.go @@ -366,23 +366,24 @@ func fchown(fd int, uid p9.UID, gid p9.GID) error { } // Open implements p9.File. -func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { +func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { if l.isOpen() { panic(fmt.Sprintf("attempting to open already opened file: %q", l.hostPath)) } // Check if control file can be used or if a new open must be created. var newFile *fd.FD - if mode == p9.ReadOnly { - log.Debugf("Open reusing control file, mode: %v, %q", mode, l.hostPath) + if flags == p9.ReadOnly { + log.Debugf("Open reusing control file, flags: %v, %q", flags, l.hostPath) newFile = l.file } else { // Ideally reopen would call name_to_handle_at (with empty name) and // open_by_handle_at to reopen the file without using 'hostPath'. However, // name_to_handle_at and open_by_handle_at aren't supported by overlay2. - log.Debugf("Open reopening file, mode: %v, %q", mode, l.hostPath) + log.Debugf("Open reopening file, flags: %v, %q", flags, l.hostPath) var err error - newFile, err = reopenProcFd(l.file, openFlags|mode.OSFlags()) + // Constrain open flags to the open mode and O_TRUNC. + newFile, err = reopenProcFd(l.file, openFlags|(flags.OSFlags()&(syscall.O_ACCMODE|syscall.O_TRUNC))) if err != nil { return nil, p9.QID{}, 0, extractErrno(err) } @@ -409,7 +410,7 @@ func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { } l.file = newFile } - l.mode = mode + l.mode = flags & p9.OpenFlagsModeMask return fd, l.attachPoint.makeQID(stat), 0, nil } |