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
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
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
Fabricio Voznika
Jamie Liu
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