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authorJamie Liu <jamieliu@google.com>2019-11-06 17:10:30 -0800
committergVisor bot <gvisor-bot@google.com>2019-11-06 17:11:58 -0800
commitf8ffadddb39e132605f0ef3e3d39e5d7ad6e0ecf (patch)
treedd66085f179f7702dacaa7686e7b80fdfa4a5ede /runsc
parente63db5e7bbf8decc6f799965f54fcf7aa6673527 (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.go13
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
}