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authorMichael Pratt <mpratt@google.com>2019-05-20 16:52:03 -0700
committerShentubot <shentubot@google.com>2019-05-20 16:53:08 -0700
commit80cc2c78e52389015459114b1689cd3265726679 (patch)
tree7e22337fdd4dbaa91b7124e863e48368cf4ea83f /pkg/sentry/fs/ashmem
parent6588427451c605ee00c8b1a9b6cba06724627ccb (diff)
Forward named pipe creation to the gofer
The backing 9p server must allow named pipe creation, which the runsc fsgofer currently does not. There are small changes to the overlay here. GetFile may block when opening a named pipe, which can cause a deadlock: 1. open(O_RDONLY) -> copyMu.Lock() -> GetFile() 2. open(O_WRONLY) -> copyMu.Lock() -> Deadlock A named pipe usable for writing must already be on the upper filesystem, but we are still taking copyMu for write when checking for upper. That can be changed to a read lock to fix the common case. However, a named pipe on the lower filesystem would still deadlock in open(O_WRONLY) when it tries to actually perform copy up (which would simply return EINVAL). Move the copy up type check before taking copyMu for write to avoid this. p9 must be modified, as it was incorrectly removing the file mode when sending messages on the wire. PiperOrigin-RevId: 249154033 Change-Id: Id6637130e567b03758130eb6c7cdbc976384b7d6
Diffstat (limited to 'pkg/sentry/fs/ashmem')
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