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
There was a very bare get/setxattr in the InodeOperations interface. Add
context.Context to both, size to getxattr, and flags to setxattr.
Note that extended attributes are passed around as strings in this
implementation, so size is automatically encoded into the value. Size is
added in getxattr so that implementations can return ERANGE if a value is larger
than can fit in the user-allocated buffer. This prevents us from unnecessarily
passing around an arbitrarily large xattr when the user buffer is actually too
small.
Don't use the existing xattrwalk and xattrcreate messages and define our
own, mainly for the sake of simplicity.
Extended attributes will be implemented in future commits.
PiperOrigin-RevId: 290121300
* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.
This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.
Updates #1472
PiperOrigin-RevId: 289033387
This also allows the tee(2) implementation to be enabled, since dup can now be
properly supported via WriteTo.
Note that this change necessitated some minor restructoring with the
fs.FileOperations splice methods. If the *fs.File is passed through directly,
then only public API methods are accessible, which will deadlock immediately
since the locking is already done by fs.Splice. Instead, we pass through an
abstract io.Reader or io.Writer, which elide locks and use the underlying
fs.FileOperations directly.
PiperOrigin-RevId: 268805207
Get/Set pipe size and ioctl support were missing from
overlayfs. It required moving the pipe.Sizer interface
to fs so that overlay could get access.
Fixes#318
PiperOrigin-RevId: 255511125
Currently, the overlay dirCache is only used for a single logical use of
getdents. i.e., it is discard when the FD is closed or seeked back to
the beginning.
But the initial work of getting the directory contents can be quite
expensive (particularly sorting large directories), so we should keep it
as long as possible.
This is very similar to the readdirCache in fs/gofer.
Since the upper filesystem does not have to allow caching readdir
entries, the new CacheReaddir MountSourceOperations method controls this
behavior.
This caching should be trivially movable to all Inodes if desired,
though that adds an additional copy step for non-overlay Inodes.
(Overlay Inodes already do the extra copy).
PiperOrigin-RevId: 255477592
This does not actually implement an efficient splice or sendfile. Rather, it
adds a generic plumbing to the file internals so that this can be added. All
file implementations use the stub fileutil.NoSplice implementation, which
causes sendfile and splice to fall back to an internal copy.
A basic splice system call interface is added, along with a test.
PiperOrigin-RevId: 249335960
Change-Id: Ic5568be2af0a505c19e7aec66d5af2480ab0939b
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
RootFromContext can return a dirent with reference taken, or nil. We must call
DecRef if (and only if) a real dirent is returned.
PiperOrigin-RevId: 242965515
Change-Id: Ie2b7b4cb19ee09b6ccf788b71f3fd7efcdf35a11
overlayFileOperations.Readdir was holding overlay.copyMu while calling
DirentReaddir, which then attempts to take take the corresponding Dirent.mu,
causing a lock order violation. (See lock order documentation in
fs/copy_up.go.)
We only actually need to hold copyMu during readdirEntries(), so holding the
lock is moved in there, thus avoiding the lock order violation.
A new lock was added to protect overlayFileOperations.dirCache. We were
inadvertently relying on copyMu to protect this. There is no reason it should
not have its own lock.
PiperOrigin-RevId: 228542473
Change-Id: I03c3a368c8cbc0b5a79d50cc486fc94adaddc1c2
If we have an overlay file whose corresponding Dirent is frozen, then we should
not bother calling Readdir on the upper or lower files, since DirentReaddir
will calculate children based on the frozen Dirent tree.
A test was added that fails without this change.
PiperOrigin-RevId: 213531215
Change-Id: I4d6c98f1416541a476a34418f664ba58f936a81d
In the general case with an overlay, all mmap calls must go through the
overlay, because in the event of a copy-up, the overlay needs to invalidate any
previously-created mappings.
If there if no lower file, however, there will never be a copy-up, so the
overlay can delegate directly to the upper file in that case.
This also allows us to correctly mmap /dev/zero when it is in an overlay. This
file has special semantics which the overlay does not know about. In
particular, it does not implement Mappable(), which (in the general case) the
overlay uses to detect if a file is mappable or not.
PiperOrigin-RevId: 205306743
Change-Id: I92331649aa648340ef6e65411c2b42c12fa69631
Adin Scannell
Dean Deng
Ian Gudger
Fabricio Voznika
Michael Pratt
Nicolas Lacasse
Jamie Liu
Zhaozhong Ni
Googler