The comments in the ticket indicate that this behavior
is fine and that the ticket should be closed, so we shouldn't
need pointers to the ticket.
PiperOrigin-RevId: 306266071
Determine system time from within the sentry rather than relying on the remote
filesystem to prevent inconsistencies.
Resolve related TODOs; the time discrepancies in question don't exist anymore.
PiperOrigin-RevId: 305557099
When copyUp fails, we attempt to clean up the upper filesystem by removing any
files that have already been copied-up. If the cleanup fails, we panic because
the "overlay filesystem is in an inconsistent state".
This CL adds the original copy-up error to the panic information, to hopefully
make it easier to track down how the overlay filesystem got into the
inconsistent state.
PiperOrigin-RevId: 304053370
Using the host-defined file owner matches VFS1. It is more correct to use the
host-defined mode, since the cached value may become out of date. However,
kernfs.Inode.Mode() does not return an error--other filesystems on kernfs are
in-memory so retrieving mode should not fail. Therefore, if the host syscall
fails, we rely on a cached value instead.
Updates #1672.
PiperOrigin-RevId: 303220864
Refactor fs/host.TTYFileOperations so that the relevant functionality can be
shared with VFS2 (fsimpl/host.ttyFD).
Incorporate host.defaultFileFD into the default host.fileDescription. This way,
there is no need for a separate default_file.go. As in vfs1, the TTY file
implementation can be built on top of this default and override operations as
necessary (PRead/Read/PWrite/Write, Release, Ioctl).
Note that these changes still need to be plumbed into runsc, which refers to
imported TTYs in control/proc.go:ExecAsync.
Updates #1672.
PiperOrigin-RevId: 301718157
- When setting up the virtual filesystem, mount a host.filesystem to contain
all files that need to be imported.
- Make read/preadv syscalls to the host in cases where preadv2 may not be
supported yet (likewise for writing).
- Make save/restore functions in kernel/kernel.go return early if vfs2 is
enabled.
PiperOrigin-RevId: 300922353
- Make oomScoreAdj a ThreadGroup field (Linux: signal_struct::oom_score_adj).
- Avoid deadlock caused by Task.OOMScoreAdj()/SetOOMScoreAdj() locking Task.mu
and TaskSet.mu in the wrong order (via Task.ExitState()).
PiperOrigin-RevId: 300814698
In VFS2, imported file descriptors are stored in a kernfs-based filesystem.
Upon calling ImportFD, the host fd can be accessed in two ways:
1. a FileDescription that can be added to the FDTable, and
2. a Dentry in the host.filesystem mount, which we will want to access through
magic symlinks in /proc/[pid]/fd/.
An implementation of the kernfs.Inode interface stores a unique host fd. This
inode can be inserted into file descriptions as well as dentries.
This change also plumbs in three FileDescriptionImpls corresponding to fds for
sockets, TTYs, and other files (only the latter is implemented here).
These implementations will mostly make corresponding syscalls to the host.
Where possible, the logic is ported over from pkg/sentry/fs/host.
Updates #1672
PiperOrigin-RevId: 299417263
When list elements are removed from a list but not discarded, it becomes
important to invalidate the references they hold to their former
neighbors to prevent memory leaks.
PiperOrigin-RevId: 299412421
Adds an oom_score_adj and oom_score proc file stub. oom_score_adj accepts
writes of values -1000 to 1000 and persists the value with the task. New tasks
inherit the parent's oom_score_adj.
oom_score is a read-only stub that always returns the value '0'.
Issue #202
PiperOrigin-RevId: 299245355
/dev/net/tun does not currently work with hostinet. This has caused some
program starts failing because it thinks the feature exists.
PiperOrigin-RevId: 297876196
MayDelete must lock the directory also, otherwise concurrent renames may
race. Note that this also changes the methods to be aligned with the actual
Remove and RemoveDirectory methods to minimize confusion when reading the
code. (It was hard to see that resolution was correct.)
PiperOrigin-RevId: 297258304
Each mount is holds a reference on a root Dirent, but the mount itself may
live beyond it's own reference. This means that a call to Root() can come
after the associated reference has been dropped.
Instead of introducing a separate layer of references for mount objects,
we simply change the Root() method to use TryIncRef() and allow it to return
nil if the mount is already gone. This requires updating a small number of
callers and minimizes the change (since VFSv2 will replace this code shortly).
PiperOrigin-RevId: 297174230
TCP/IP will work with netstack networking. hostinet doesn't work, and sockets
will have the same behavior as it is now.
Before the userspace is able to create device, the default loopback device can
be used to test.
/proc/net and /sys/net will still be connected to the root network stack; this
is the same behavior now.
Issue #1833
PiperOrigin-RevId: 296309389
- Added fsbridge package with interface that can be used to open
and read from VFS1 and VFS2 files.
- Converted ELF loader to use fsbridge
- Added VFS2 types to FSContext
- Added vfs.MountNamespace to ThreadGroup
Updates #1623
PiperOrigin-RevId: 295183950
Fixes#1812. (The more direct cause of the deadlock is panic unsafety because
the historically high cost of defer means that we avoid it in hot paths,
including much of MM; defer is much cheaper as of Go 1.14, but still a
measurable overhead.)
PiperOrigin-RevId: 294560316
The slaveInodeOperations is currently copying the object when
truncate is called (which is a no-op). This may result in a
(unconsequential) data race when being modified concurrently.
PiperOrigin-RevId: 294484276
Updates #1198
Opening host pipes (by spinning in fdpipe) and host sockets is not yet
complete, and will be done in a future CL.
Major differences from VFS1 gofer client (sentry/fs/gofer), with varying levels
of backportability:
- "Cache policies" are replaced by InteropMode, which control the behavior of
timestamps in addition to caching. Under InteropModeExclusive (analogous to
cacheAll) and InteropModeWritethrough (analogous to cacheAllWritethrough),
client timestamps are *not* written back to the server (it is not possible in
9P or Linux for clients to set ctime, so writing back client-authoritative
timestamps results in incoherence between atime/mtime and ctime). Under
InteropModeShared (analogous to cacheRemoteRevalidating), client timestamps
are not used at all (remote filesystem clocks are authoritative). cacheNone
is translated to InteropModeShared + new option
filesystemOptions.specialRegularFiles.
- Under InteropModeShared, "unstable attribute" reloading for permission
checks, lookup, and revalidation are fused, which is feasible in VFS2 since
gofer.filesystem controls path resolution. This results in a ~33% reduction
in RPCs for filesystem operations compared to cacheRemoteRevalidating. For
example, consider stat("/foo/bar/baz") where "/foo/bar/baz" fails
revalidation, resulting in the instantiation of a new dentry:
VFS1 RPCs:
getattr("/") // fs.MountNamespace.FindLink() => fs.Inode.CheckPermission() => gofer.inodeOperations.check() => gofer.inodeOperations.UnstableAttr()
walkgetattr("/", "foo") = fid1 // fs.Dirent.walk() => gofer.session.Revalidate() => gofer.cachePolicy.Revalidate()
clunk(fid1)
getattr("/foo") // CheckPermission
walkgetattr("/foo", "bar") = fid2 // Revalidate
clunk(fid2)
getattr("/foo/bar") // CheckPermission
walkgetattr("/foo/bar", "baz") = fid3 // Revalidate
clunk(fid3)
walkgetattr("/foo/bar", "baz") = fid4 // fs.Dirent.walk() => gofer.inodeOperations.Lookup
getattr("/foo/bar/baz") // linux.stat() => gofer.inodeOperations.UnstableAttr()
VFS2 RPCs:
getattr("/") // gofer.filesystem.walkExistingLocked()
walkgetattr("/", "foo") = fid1 // gofer.filesystem.stepExistingLocked()
clunk(fid1)
// No getattr: walkgetattr already updated metadata for permission check
walkgetattr("/foo", "bar") = fid2
clunk(fid2)
walkgetattr("/foo/bar", "baz") = fid3
// No clunk: fid3 used for new gofer.dentry
// No getattr: walkgetattr already updated metadata for stat()
- gofer.filesystem.unlinkAt() does not require instantiation of a dentry that
represents the file to be deleted. Updates #898.
- gofer.regularFileFD.OnClose() skips Tflushf for regular files under
InteropModeExclusive, as it's nonsensical to request a remote file flush
without flushing locally-buffered writes to that remote file first.
- Symlink targets are cached when InteropModeShared is not in effect.
- p9.QID.Path (which is already required to be unique for each file within a
server, and is accordingly already synthesized from device/inode numbers in
all known gofers) is used as-is for inode numbers, rather than being mapped
along with attr.RDev in the client to yet another synthetic inode number.
- Relevant parts of fsutil.CachingInodeOperations are inlined directly into
gofer package code. This avoids having to duplicate part of its functionality
in fsutil.HostMappable.
PiperOrigin-RevId: 293190213
Splice must not allow negative offsets. Writes also must not allow offset +
size to overflow int64. Reads are similarly broken, but not just in splice
(b/148095030).
Reported-by: syzbot+0e1ff0b95fb2859b4190@syzkaller.appspotmail.com
PiperOrigin-RevId: 292361208
Special files can have additional requirements for granularity.
For example, read from eventfd returns EINVAL if a size is less 8 bytes.
Reported-by: syzbot+3905f5493bec08eb7b02@syzkaller.appspotmail.com
PiperOrigin-RevId: 292002926
Because the abi will depend on the core types for marshalling (usermem,
context, safemem, safecopy), these need to be flattened from the sentry
directory. These packages contain no sentry-specific details.
PiperOrigin-RevId: 291811289
Also renames TMutex to Mutex.
These custom mutexes aren't any worse than the standard library versions (same
code), so having both seems redundant.
PiperOrigin-RevId: 290873587
Java 11 parses /proc/self/mountinfo for cgroup information. Java 11.0.4 uses
the mount path to determine what cgroups existed, but Java 11.0.5 reads the
cgroup names from the superblock options.
This CL adds the cgroup name to the superblock options if the filesystem type
is "cgroup". Since gVisor doesn't actually support cgroups yet, we just infer
the cgroup name from the path.
PiperOrigin-RevId: 290434323
Fabricio Voznika
Dave Bailey
Jon Budd
gVisor bot
Jamie Liu
Dean Deng
Adin Scannell
Nicolas Lacasse
Zach Koopmans
Ting-Yu Wang
Tamir Duberstein
Ian Lewis
Michael Pratt
Andrei Vagin
Ian Gudger