From man TIOCPKT:
"""
In packet mode, each subsequent read(2) will return a packet that either
contains a single nonzero control byte, or has a single byte containing zero
('\0') followed by data written on the slave side of the pseudoterminal."
"""
This CL implements only the data portion of packet mode, not the control bytes,
but that seems to be enough to get xfce4-terminal to work.
PiperOrigin-RevId: 737175092
Previously, CheckChange (corresponding to Linux's tty/tty_check_change()) was
only used the host TTY implementation, not the devpts implementation.
Furthermore, ThreadGroup.SetForegroundProcessGroup() duplicated some of the
logic in CheckChange, notably sending SIGTTOU to background tasks. This means
that, for host TTYs, we could send SIGTTOU multiple times. In some
circumstances, this leads the ioctl returning ERESTARTSYS in an infinite loop.
PiperOrigin-RevId: 735934036
We used to track the foreground process group & session on the
TTYFileOperation, but these are already tracked in kernel.TTY.ThreadGroup.
So remove TTYFileOperations.fgProcessGroup and .session, and replace them with
a kernel.TTY.
This is analogous to how sentry-internal tty's already work.
Updates #10925
PiperOrigin-RevId: 681957240
While there is a difference between flavors of this ioctl (`TCSETS`,
`TCSETSF`, `TCSETSW`), in practice it seems not to matter. We should let
users call `TCSETSF` and can implement those differences if necessary.
These inodes can never be part of a filesystem tree. They are nameless and
never have a parent.
This allows us to avoid taking a lock in kernfs.InotifyWithParent for such
anonymous inodes.
PiperOrigin-RevId: 538823227
This catches up the interface to the `EmitUnimplementedEvent` method signature
on `kernel.Kernel`.
Also add build-time test to verify that `kernel.Kernel` implements this
interface, in order to catch such breakages at build time in the future.
PiperOrigin-RevId: 519000411
We no longer store the foreground process directly in the terminal. Instead, we
get it from the terminal TTY's ThreadGroup. Added a new method:
tty.SignalForegroundProcessGroup to simplify this.
Cleaned up some things along the way:
* Terminal had a bunch of methods to get/set foreground process group and
controlling TTY, but those methods were only usable by Ioctl, since they
read/wrote to syscall arguments. I moved that logic to Ioctl, and deleted the
methods from Terminal, which is now a very simple type.
* Fixed a bug in ThreadGroud.SetForegroundProcessGroup where we were
overwriting the ID of an existing process group, rather than setting a new
process group on the session.
* Simplified the construction of lineDiscipline type.
Reported-by: syzbot+ae5b769cec8ad969c086@syzkaller.appspotmail.com
PiperOrigin-RevId: 512330758
This is consistent with Linux. Some applications recursively add
files to inotify FD. They fail if they run into kernfs files
because inotify_add_watch(2) returns EPERM in that case.
PiperOrigin-RevId: 462642204
Linux behaves differently for regular files and dirs for poll(2)/select(2)
compared to epoll_ctl(2). The latter returns EPERM for file and dirs.
I've also changed host FDs to behave like the underlying FD in regards
to epoll to keep it compatible with docker.
Fixes#7134
PiperOrigin-RevId: 429412692
Docker maps stdin to `/dev/null` which doesn't support epoll. Host FD
was ignoring the error and suceeding the epoll_ctl call from the
container, giving false impressing that epoll would be notified.
This required plumbing failure to all waiter.Waitable.EventRegister
callers and implementers.
Closes#6795
PiperOrigin-RevId: 414797621
Instead of passing the event mask at registratrion time, pass the mask as part
of the waiter. This makes the mask immutable and simplifies the architecture of
waiters. This is also necessary for a future fix that will allow the fdnotifier
to keep persistent entries, as opposed to requiring constant updates.
This change is intended to be a no-op in terms of function. The only exception
is signalfd, where this mask was abused. To handle this case, the operation of
signalfd changed to allow one layer of indirection.
PiperOrigin-RevId: 409702998
Remove three syserror entries duplicated in linuxerr. Because of the
linuxerr.Equals method, this is a mere change of return values from
syserror to linuxerr definitions.
Done with only these three errnos as CLs removing all grow to a significantly
large size.
PiperOrigin-RevId: 382173835
Added the following fields in kernfs.InodeAttr:
- blockSize
- atime
- mtime
- ctime
Also resolved all TODOs for #1193.
Fixes#1193
PiperOrigin-RevId: 338714527
This change aims to fix the memory leak issue reported in #3933.
Background:
VFS2 kernfs kept accumulating invalid dentries if those dentries were not
walked on. After substantial consideration of the problem by our team, we
decided to have an LRU cache solution. This change is the first part to that
solution, where we don't cache anything. The LRU cache can be added on top of
this.
What has changed:
- Introduced the concept of an inode tree in kernfs.OrderedChildren.
This is helpful is cases where the lifecycle of an inode is different from
that of a dentry.
- OrderedChildren now deals with initialized inodes instead of initialized
dentries. It now implements Lookup() where it constructs a new dentry
using the inode.
- OrderedChildren holds a ref on all its children inodes. With this change,
now an inode can "outlive" a dentry pointing to it. See comments in
kernfs.OrderedChildren.
- The kernfs dentry tree is solely maintained by kernfs only. Inode
implementations can not modify the dentry tree.
- Dentries that reach ref count 0 are removed from the dentry tree.
- revalidateChildLocked now defer-DecRefs the newly created dentry from
Inode.Lookup(), limiting its life to the current filesystem operation. If
refs are picked on the dentry during the FS op (via an FD or something),
then it will stick around and will be removed when the FD is closed. So there
is essentially _no caching_ for Look()ed up dentries.
- kernfs.DecRef does not have the precondition that fs.mu must be locked.
Fixes#3933
PiperOrigin-RevId: 336768576
The FD should hold a reference on the dentry they were opened on which in turn
holds a reference on the inode it points to.
PiperOrigin-RevId: 333589223
