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path: root/pkg/sentry/vfs/epoll.go
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2020-09-15Read vfs2 epoll events atomically.Jamie Liu
Discovered by ayushranjan@: VFS2 was employing the following algorithm for fetching ready events from an epoll instance: - Create a statically sized EpollEvent slice on the stack of size 16. - Pass that to EpollInstance.ReadEvents() to populate. - EpollInstance.ReadEvents() requeues level-triggered events that it returns back into the ready queue. - Write the results to usermem. - If the number of results were = 16 then recall EpollInstance.ReadEvents() in the hopes of getting more. But this will cause duplication of the "requeued" ready level-triggered events. So if the ready queue has >= 16 ready events, the EpollWait for loop will spin until it fills the usermem with `maxEvents` events. Fixes #3521 PiperOrigin-RevId: 331840527
2020-08-03Plumbing context.Context to DecRef() and Release().Nayana Bidari
context is passed to DecRef() and Release() which is needed for SO_LINGER implementation. PiperOrigin-RevId: 324672584
2020-07-29Force registration for EPOLLHUP, not EPOLLRDHUP, in vfs2's epoll.Jamie Liu
Compare Linux's fs/eventpoll.c:do_epoll_ctl(). I don't know where EPOLLRDHUP came from. PiperOrigin-RevId: 323874419
2020-06-09Implement flock(2) in VFS2Fabricio Voznika
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
2020-05-04Add TTY support on VFS2 to runscFabricio Voznika
Updates #1623, #1487 PiperOrigin-RevId: 309777922
2020-04-02Add equivalents to FMODE_PREAD/PWRITE to VFS2.Jamie Liu
This is mostly required for PipeTest_OffsetCalls. The options are DenyPRead/PWrite rather than AllowPRead/PWrite since, in Linux terms, fs/open.c:do_dentry_open sets FMODE_PREAD|FMODE_PWRITE unconditionally (although it allows filesystem implementations of open to unset these flags), so they're set for most FDs; it's usually FDs created outside of open(2) that don't get them, e.g.: - Syscall-created pipes (fs/pipe.c:create_pipe_files => fs/file_table.c:alloc_file_pseudo) - Epoll instances (fs/eventpoll.c:do_epoll_create => fs/anon_inodes.c:anon_inode_getfile => alloc_file_pseudo) - Sockets (net/socket.c:sock_alloc_file => alloc_file_pseudo) This CL adds the flags to epoll instances; a subsequent CL reworks the VFS2 implementation of pipe FDs to be filesystem-independent and adds the flags there, and sockets aren't implemented yet. Updates #1035 PiperOrigin-RevId: 304506434
2020-02-25Port most syscalls to VFS2.Jamie Liu
pipe and pipe2 aren't ported, pending a slight rework of pipe FDs for VFS2. mount and umount2 aren't ported out of temporary laziness. access and faccessat need additional FSImpl methods to implement properly, but are stubbed to prevent googletest from CHECK-failing. Other syscalls require additional plumbing. Updates #1623 PiperOrigin-RevId: 297188448
2020-02-14Remove linux.EpollEvent.Fd.gVisor bot
glibc defines struct epoll_event in such a way that epoll_event.data.fd exists. However, the kernel's definition of struct epoll_event makes epoll_event.data an opaque uint64, so naming half of it "fd" just introduces confusion. Remove the Fd field, and make Data a [2]int32 to compensate. Also add required padding to linux.EpollEvent on ARM64. PiperOrigin-RevId: 295250424
2020-01-28Add VFS2 support for epoll.Jamie Liu
PiperOrigin-RevId: 291997879