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path: root/pkg/sentry/fs/fsutil
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2021-05-25setgid directories for VFS1 tmpfs, overlayfs, and goferfsKevin Krakauer
PiperOrigin-RevId: 375780659
2021-03-29[syserror] Split usermem packageZach Koopmans
Split usermem package to help remove syserror dependency in go_marshal. New hostarch package contains code not dependent on syserror. PiperOrigin-RevId: 365651233
2021-03-22Avoid calling sync on each write in writethrough mode.Nicolas Lacasse
PiperOrigin-RevId: 364370595
2021-03-03[op] Replace syscall package usage with golang.org/x/sys/unix in pkg/.Ayush Ranjan
The syscall package has been deprecated in favor of golang.org/x/sys. Note that syscall is still used in the following places: - pkg/sentry/socket/hostinet/stack.go: some netlink related functionalities are not yet available in golang.org/x/sys. - syscall.Stat_t is still used in some places because os.FileInfo.Sys() still returns it and not unix.Stat_t. Updates #214 PiperOrigin-RevId: 360701387
2021-01-12Fix simple mistakes identified by goreportcard.Adin Scannell
These are primarily simplification and lint mistakes. However, minor fixes are also included and tests added where appropriate. PiperOrigin-RevId: 351425971
2020-10-23Support VFS2 save/restore.Jamie Liu
Inode number consistency checks are now skipped in save/restore tests for reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename. They pass in VFS1 due to the bug described in new test case SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs. Fixes #1663 PiperOrigin-RevId: 338776148
2020-10-13Don't read beyond EOF when inserting into sentry page cache.Jamie Liu
The sentry page cache stores file contents at page granularity; this is necessary for memory mappings. Thus file offset ranges passed to fsutil.FileRangeSet.Fill() must be page-aligned. If the read callback passed to Fill() returns (partial read, nil error) when reading up to EOF (which is the case for p9.ClientFile.ReadAt() since 9P's Rread cannot convey both a partial read and EOF), Fill() will re-invoke the read callback to try to read from EOF to the end of the containing page, which is harmless but needlessly expensive. Fix this by handling file size explicitly in fsutil.FileRangeSet.Fill(). PiperOrigin-RevId: 336934075
2020-10-07Add staticcheck and staticstyle analyzers.Adin Scannell
This change also adds support to go_stateify for detecting an appropriate receiver name, avoiding a large number of false positives. PiperOrigin-RevId: 335994587
2020-08-20Consistent precondition formattingMichael Pratt
Our "Preconditions:" blocks are very useful to determine the input invariants, but they are bit inconsistent throughout the codebase, which makes them harder to read (particularly cases with 5+ conditions in a single paragraph). I've reformatted all of the cases to fit in simple rules: 1. Cases with a single condition are placed on a single line. 2. Cases with multiple conditions are placed in a bulleted list. This format has been added to the style guide. I've also mentioned "Postconditions:", though those are much less frequently used, and all uses already match this style. PiperOrigin-RevId: 327687465
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
2020-07-27Move platform.File in memmapAndrei Vagin
The subsequent systrap changes will need to import memmap from the platform package. PiperOrigin-RevId: 323409486
2020-05-19Implement mmap for host fs in vfs2.Dean Deng
In VFS1, both fs/host and fs/gofer used the same utils for host file mappings. Refactor parts of fsimpl/gofer to create similar utils to share with fsimpl/host (memory accounting code moved to fsutil, page rounding arithmetic moved to usermem). Updates #1476. PiperOrigin-RevId: 312345090
2020-03-02Take write lock when removing xattrMichael Pratt
PiperOrigin-RevId: 298380654
2020-02-11Ensure fsimpl/gofer.dentryPlatformFile.hostFileMapper is initialized.gVisor bot
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
2020-02-07Support listxattr and removexattr syscalls.Dean Deng
Note that these are only implemented for tmpfs, and other impls will still return EOPNOTSUPP. PiperOrigin-RevId: 293899385
2020-02-04VFS2 gofer clientJamie Liu
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
2020-01-27Update package locations.Adin Scannell
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
2020-01-27Standardize on tools directory.Adin Scannell
PiperOrigin-RevId: 291745021
2020-01-16Plumb getting/setting xattrs through InodeOperations and 9p gofer interfaces.Dean Deng
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
2020-01-09New sync package.Ian Gudger
* 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
2020-01-06Convert memfs into proto-tmpfs.Nicolas Lacasse
- Renamed memfs to tmpfs. - Copied fileRangeSet bits from fs/fsutil/ to fsimpl/tmpfs/ - Changed tmpfs to be backed by filemem instead of byte slice. - regularFileReadWriter uses a sync.Pool, similar to gofer client. PiperOrigin-RevId: 288356380
2019-10-16Reorder BUILD license and load functions in gvisor.Kevin Krakauer
PiperOrigin-RevId: 275139066
2019-10-16Fix problem with open FD when copy up is triggered in overlayfsFabricio Voznika
Linux kernel before 4.19 doesn't implement a feature that updates open FD after a file is open for write (and is copied to the upper layer). Already open FD will continue to read the old file content until they are reopened. This is especially problematic for gVisor because it caches open files. Flag was added to force readonly files to be reopenned when the same file is open for write. This is only needed if using kernels prior to 4.19. Closes #1006 It's difficult to really test this because we never run on tests on older kernels. I'm adding a test in GKE which uses kernels with the overlayfs problem for 1.14 and lower. PiperOrigin-RevId: 275115289
2019-09-30Force timestamps to update when set via InodeOperations.SetTimestamps.Nicolas Lacasse
The gofer's CachingInodeOperations implementation contains an optimization for the common open-read-close pattern when we have a host FD. In this case, the host kernel will update the timestamp for us to a reasonably close time, so we don't need an extra RPC to the gofer. However, when the app explicitly sets the timestamps (via futimes or similar) then we actually DO need to update the timestamps, because the host kernel won't do it for us. To fix this, a new boolean `forceSetTimestamps` was added to CachineInodeOperations.SetMaskedAttributes. It is only set by gofer.InodeOperations.SetTimestamps. PiperOrigin-RevId: 272048146
2019-09-12Implement splice methods for pipes and sockets.Adin Scannell
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
2019-09-12Remove go_test from go_stateify and go_marshalMichael Pratt
They are no-ops, so the standard rule works fine. PiperOrigin-RevId: 268776264
2019-08-30Remove support for non-incremental mapped accounting.Jamie Liu
PiperOrigin-RevId: 266496644
2019-08-29Add limit_host_fd_translation Gofer mount option.Jamie Liu
PiperOrigin-RevId: 266177409
2019-07-30Cache pages in CachingInodeOperations.Read when memory evictions are delayed.Jamie Liu
PiperOrigin-RevId: 260851452
2019-06-27Complete pipe support on overlayfsFabricio Voznika
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
2019-06-27Cache directory entries in the overlayMichael Pratt
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
2019-06-13Plumb context through more layers of filesytem.Ian Gudger
All functions which allocate objects containing AtomicRefCounts will soon need a context. PiperOrigin-RevId: 253147709
2019-06-13Update canonical repository.Adin Scannell
This can be merged after: https://github.com/google/gvisor-website/pull/77 or https://github.com/google/gvisor-website/pull/78 PiperOrigin-RevId: 253132620
2019-05-21Add basic plumbing for splice and stub implementation.Adin Scannell
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
2019-05-20Fix incorrect tmpfs timestamp updatesMichael Pratt
* Creation of files, directories (and other fs objects) in a directory should always update ctime. * Same for removal. * atime should not be updated on lookup, only readdir. I've also renamed some misleading functions that update mtime and ctime. PiperOrigin-RevId: 249115063 Change-Id: I30fa275fa7db96d01aa759ed64628c18bb3a7dc7
2019-05-17Fix gofer rename ctime and cleanup stat_times testMichael Pratt
There is a lot of redundancy that we can simplify in the stat_times test. This will make it easier to add new tests. However, the simplification reveals that cached uattrs on goferfs don't properly update ctime on rename. PiperOrigin-RevId: 248773425 Change-Id: I52662728e1e9920981555881f9a85f9ce04041cf
2019-05-09Implement fallocate(2)Fabricio Voznika
Closes #225 PiperOrigin-RevId: 247508791 Change-Id: I04f47cf2770b30043e5a272aba4ba6e11d0476cc
2019-04-30Implement async MemoryFile eviction, and use it in CachingInodeOperations.Jamie Liu
This feature allows MemoryFile to delay eviction of "optional" allocations, such as unused cached file pages. Note that this incidentally makes CachingInodeOperations writeback asynchronous, in the sense that it doesn't occur until eviction; this is necessary because between when a cached page becomes evictable and when it's evicted, file writes (via CachingInodeOperations.Write) may dirty the page. As currently implemented, this feature won't meaningfully impact steady-state memory usage or caching; the reclaimer goroutine will schedule eviction as soon as it runs out of other work to do. Future CLs increase caching by adding constraints on when eviction is scheduled. PiperOrigin-RevId: 246014822 Change-Id: Ia85feb25a2de92a48359eb84434b6ec6f9bea2cb
2019-04-29Change copyright notice to "The gVisor Authors"Michael Pratt
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
2019-04-29Allow and document bug ids in gVisor codebase.Nicolas Lacasse
PiperOrigin-RevId: 245818639 Change-Id: I03703ef0fb9b6675955637b9fe2776204c545789
2019-04-11Use open fids when fstat()ing gofer files.Jamie Liu
PiperOrigin-RevId: 243018347 Change-Id: I1e5b80607c1df0747482abea61db7fcf24536d37
2019-04-10Fix uses of RootFromContext.Nicolas Lacasse
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
2019-04-10Fixed /proc/cpuinfo permissionsShiva Prasanth
This also applies these permissions to other static proc files. Change-Id: I4167e585fed49ad271aa4e1f1260babb3239a73d PiperOrigin-RevId: 242898575
2019-04-05Use string type for extended attribute values, instead of []byte.Nicolas Lacasse
Strings are a better fit for this usage because they are immutable in Go, and can contain arbitrary bytes. It also allows us to avoid casting bytes to string (and the associated allocation) in the hot path when checking for overlay whiteouts. PiperOrigin-RevId: 242208856 Change-Id: I7699ae6302492eca71787dd0b72e0a5a217a3db2
2019-03-28Clean up gofer handle caching.Jamie Liu
- Document fsutil.CachedFileObject.FD() requirements on access permissions, and change gofer.inodeFileState.FD() to honor them. Fixes #147. - Combine gofer.inodeFileState.readonly and gofer.inodeFileState.readthrough, and simplify handle caching logic. - Inline gofer.cachePolicy.cacheHandles into gofer.inodeFileState.setSharedHandles, because users with access to gofer.inodeFileState don't necessarily have access to the fs.Inode (predictably, this is a save/restore problem). Before this CL: $ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash root@34d51017ed67:/# /root/repro/runsc-b147 mmap: 0x7f3c01e45000 Segmentation fault After this CL: $ docker run --runtime=runsc-d -v $(pwd)/gvisor/repro:/root/repro -it ubuntu bash root@d3c3cb56bbf9:/# /root/repro/runsc-b147 mmap: 0x7f78987ec000 o PiperOrigin-RevId: 240818413 Change-Id: I49e1d4a81a0cb9177832b0a9f31a10da722a896b
2019-03-25Call memmap.Mappable.Translate with more conservative usermem.AccessType.Jamie Liu
MM.insertPMAsLocked() passes vma.maxPerms to memmap.Mappable.Translate (although it unsets AccessType.Write if the vma is private). This somewhat simplifies handling of pmas, since it means only COW-break needs to replace existing pmas. However, it also means that a MAP_SHARED mapping of a file opened O_RDWR dirties the file, regardless of the mapping's permissions and whether or not the mapping is ever actually written to with I/O that ignores permissions (e.g. ptrace(PTRACE_POKEDATA)). To fix this: - Change the pma-getting path to request only the permissions that are required for the calling access. - Change memmap.Mappable.Translate to take requested permissions, and return allowed permissions. This preserves the existing behavior in the common cases where the memmap.Mappable isn't fsutil.CachingInodeOperations and doesn't care if the translated platform.File pages are written to. - Change the MM.getPMAsLocked path to support permission upgrading of pmas outside of copy-on-write. PiperOrigin-RevId: 240196979 Change-Id: Ie0147c62c1fbc409467a6fa16269a413f3d7d571
2019-03-18Remove references to replaced child in Rename in ramfs/agentfsMichael Pratt
In the case of a rename replacing an existing destination inode, ramfs Rename failed to first remove the replaced inode. This caused: 1. A leak of a reference to the inode (making it live indefinitely). 2. For directories, a leak of the replaced directory's .. link to the parent. This would cause the parent's link count to incorrectly increase. (2) is much simpler to test than (1), so that's what I've done. agentfs has a similar bug with link count only, so the Dirent layer informs the Inode if this is a replacing rename. Fixes #133 PiperOrigin-RevId: 239105698 Change-Id: I4450af2462d8ae3339def812287213d2cbeebde0
2019-03-14Decouple filemem from platform and move it to pgalloc.MemoryFile.Jamie Liu
This is in preparation for improved page cache reclaim, which requires greater integration between the page cache and page allocator. PiperOrigin-RevId: 238444706 Change-Id: Id24141b3678d96c7d7dc24baddd9be555bffafe4
2019-03-12Clarify the platform.File interface.Jamie Liu
- Redefine some memmap.Mappable, platform.File, and platform.Memory semantics in terms of File reference counts (no functional change). - Make AddressSpace.MapFile take a platform.File instead of a raw FD, and replace platform.File.MapInto with platform.File.FD. This allows kvm.AddressSpace.MapFile to always use platform.File.MapInternal instead of maintaining its own (redundant) cache of file mappings in the sentry address space. PiperOrigin-RevId: 238044504 Change-Id: Ib73a11e4275c0da0126d0194aa6c6017a9cef64f
2019-02-28Hold dataMu for writing in CachingInodeOperations.WriteOut.Jamie Liu
fsutil.SyncDirtyAll mutates the DirtySet. PiperOrigin-RevId: 236183349 Change-Id: I7e809d5b406ac843407e61eff17d81259a819b4f
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