diff options
Diffstat (limited to 'pkg/sentry/fsimpl/gofer')
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/BUILD | 89 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/dentry_list.go | 193 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/fstree.go | 46 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/gofer_state_autogen.go | 38 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/gofer_test.go | 63 |
5 files changed, 277 insertions, 152 deletions
diff --git a/pkg/sentry/fsimpl/gofer/BUILD b/pkg/sentry/fsimpl/gofer/BUILD deleted file mode 100644 index 4a800dcf9..000000000 --- a/pkg/sentry/fsimpl/gofer/BUILD +++ /dev/null @@ -1,89 +0,0 @@ -load("//tools:defs.bzl", "go_library", "go_test") -load("//tools/go_generics:defs.bzl", "go_template_instance") - -licenses(["notice"]) - -go_template_instance( - name = "dentry_list", - out = "dentry_list.go", - package = "gofer", - prefix = "dentry", - template = "//pkg/ilist:generic_list", - types = { - "Element": "*dentry", - "Linker": "*dentry", - }, -) - -go_template_instance( - name = "fstree", - out = "fstree.go", - package = "gofer", - prefix = "generic", - template = "//pkg/sentry/vfs/genericfstree:generic_fstree", - types = { - "Dentry": "dentry", - }, -) - -go_library( - name = "gofer", - srcs = [ - "dentry_list.go", - "directory.go", - "filesystem.go", - "fstree.go", - "gofer.go", - "handle.go", - "host_named_pipe.go", - "p9file.go", - "regular_file.go", - "socket.go", - "special_file.go", - "symlink.go", - "time.go", - ], - visibility = ["//pkg/sentry:internal"], - deps = [ - "//pkg/abi/linux", - "//pkg/context", - "//pkg/fd", - "//pkg/fdnotifier", - "//pkg/fspath", - "//pkg/log", - "//pkg/p9", - "//pkg/safemem", - "//pkg/sentry/fs/fsutil", - "//pkg/sentry/fs/lock", - "//pkg/sentry/fsimpl/host", - "//pkg/sentry/hostfd", - "//pkg/sentry/kernel", - "//pkg/sentry/kernel/auth", - "//pkg/sentry/kernel/pipe", - "//pkg/sentry/kernel/time", - "//pkg/sentry/memmap", - "//pkg/sentry/pgalloc", - "//pkg/sentry/platform", - "//pkg/sentry/socket/control", - "//pkg/sentry/socket/unix", - "//pkg/sentry/socket/unix/transport", - "//pkg/sentry/usage", - "//pkg/sentry/vfs", - "//pkg/syserr", - "//pkg/syserror", - "//pkg/unet", - "//pkg/usermem", - "//pkg/waiter", - "@org_golang_x_sys//unix:go_default_library", - ], -) - -go_test( - name = "gofer_test", - srcs = ["gofer_test.go"], - library = ":gofer", - deps = [ - "//pkg/p9", - "//pkg/sentry/contexttest", - ], -) diff --git a/pkg/sentry/fsimpl/gofer/dentry_list.go b/pkg/sentry/fsimpl/gofer/dentry_list.go new file mode 100644 index 000000000..fa03e2501 --- /dev/null +++ b/pkg/sentry/fsimpl/gofer/dentry_list.go @@ -0,0 +1,193 @@ +package gofer + +// ElementMapper provides an identity mapping by default. +// +// This can be replaced to provide a struct that maps elements to linker +// objects, if they are not the same. An ElementMapper is not typically +// required if: Linker is left as is, Element is left as is, or Linker and +// Element are the same type. +type dentryElementMapper struct{} + +// linkerFor maps an Element to a Linker. +// +// This default implementation should be inlined. +// +//go:nosplit +func (dentryElementMapper) linkerFor(elem *dentry) *dentry { return elem } + +// List is an intrusive list. Entries can be added to or removed from the list +// in O(1) time and with no additional memory allocations. +// +// The zero value for List is an empty list ready to use. +// +// To iterate over a list (where l is a List): +// for e := l.Front(); e != nil; e = e.Next() { +// // do something with e. +// } +// +// +stateify savable +type dentryList struct { + head *dentry + tail *dentry +} + +// Reset resets list l to the empty state. +func (l *dentryList) Reset() { + l.head = nil + l.tail = nil +} + +// Empty returns true iff the list is empty. +func (l *dentryList) Empty() bool { + return l.head == nil +} + +// Front returns the first element of list l or nil. +func (l *dentryList) Front() *dentry { + return l.head +} + +// Back returns the last element of list l or nil. +func (l *dentryList) Back() *dentry { + return l.tail +} + +// Len returns the number of elements in the list. +// +// NOTE: This is an O(n) operation. +func (l *dentryList) Len() (count int) { + for e := l.Front(); e != nil; e = e.Next() { + count++ + } + return count +} + +// PushFront inserts the element e at the front of list l. +func (l *dentryList) PushFront(e *dentry) { + linker := dentryElementMapper{}.linkerFor(e) + linker.SetNext(l.head) + linker.SetPrev(nil) + if l.head != nil { + dentryElementMapper{}.linkerFor(l.head).SetPrev(e) + } else { + l.tail = e + } + + l.head = e +} + +// PushBack inserts the element e at the back of list l. +func (l *dentryList) PushBack(e *dentry) { + linker := dentryElementMapper{}.linkerFor(e) + linker.SetNext(nil) + linker.SetPrev(l.tail) + if l.tail != nil { + dentryElementMapper{}.linkerFor(l.tail).SetNext(e) + } else { + l.head = e + } + + l.tail = e +} + +// PushBackList inserts list m at the end of list l, emptying m. +func (l *dentryList) PushBackList(m *dentryList) { + if l.head == nil { + l.head = m.head + l.tail = m.tail + } else if m.head != nil { + dentryElementMapper{}.linkerFor(l.tail).SetNext(m.head) + dentryElementMapper{}.linkerFor(m.head).SetPrev(l.tail) + + l.tail = m.tail + } + m.head = nil + m.tail = nil +} + +// InsertAfter inserts e after b. +func (l *dentryList) InsertAfter(b, e *dentry) { + bLinker := dentryElementMapper{}.linkerFor(b) + eLinker := dentryElementMapper{}.linkerFor(e) + + a := bLinker.Next() + + eLinker.SetNext(a) + eLinker.SetPrev(b) + bLinker.SetNext(e) + + if a != nil { + dentryElementMapper{}.linkerFor(a).SetPrev(e) + } else { + l.tail = e + } +} + +// InsertBefore inserts e before a. +func (l *dentryList) InsertBefore(a, e *dentry) { + aLinker := dentryElementMapper{}.linkerFor(a) + eLinker := dentryElementMapper{}.linkerFor(e) + + b := aLinker.Prev() + eLinker.SetNext(a) + eLinker.SetPrev(b) + aLinker.SetPrev(e) + + if b != nil { + dentryElementMapper{}.linkerFor(b).SetNext(e) + } else { + l.head = e + } +} + +// Remove removes e from l. +func (l *dentryList) Remove(e *dentry) { + linker := dentryElementMapper{}.linkerFor(e) + prev := linker.Prev() + next := linker.Next() + + if prev != nil { + dentryElementMapper{}.linkerFor(prev).SetNext(next) + } else { + l.head = next + } + + if next != nil { + dentryElementMapper{}.linkerFor(next).SetPrev(prev) + } else { + l.tail = prev + } + + linker.SetNext(nil) + linker.SetPrev(nil) +} + +// Entry is a default implementation of Linker. Users can add anonymous fields +// of this type to their structs to make them automatically implement the +// methods needed by List. +// +// +stateify savable +type dentryEntry struct { + next *dentry + prev *dentry +} + +// Next returns the entry that follows e in the list. +func (e *dentryEntry) Next() *dentry { + return e.next +} + +// Prev returns the entry that precedes e in the list. +func (e *dentryEntry) Prev() *dentry { + return e.prev +} + +// SetNext assigns 'entry' as the entry that follows e in the list. +func (e *dentryEntry) SetNext(elem *dentry) { + e.next = elem +} + +// SetPrev assigns 'entry' as the entry that precedes e in the list. +func (e *dentryEntry) SetPrev(elem *dentry) { + e.prev = elem +} diff --git a/pkg/sentry/fsimpl/gofer/fstree.go b/pkg/sentry/fsimpl/gofer/fstree.go new file mode 100644 index 000000000..507dc82e6 --- /dev/null +++ b/pkg/sentry/fsimpl/gofer/fstree.go @@ -0,0 +1,46 @@ +package gofer + +import ( + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/vfs" +) + +// IsAncestorDentry returns true if d is an ancestor of d2; that is, d is +// either d2's parent or an ancestor of d2's parent. +func genericIsAncestorDentry(d, d2 *dentry) bool { + for d2 != nil { + if d2.parent == d { + return true + } + if d2.parent == d2 { + return false + } + d2 = d2.parent + } + return false +} + +// ParentOrSelf returns d.parent. If d.parent is nil, ParentOrSelf returns d. +func genericParentOrSelf(d *dentry) *dentry { + if d.parent != nil { + return d.parent + } + return d +} + +// PrependPath is a generic implementation of FilesystemImpl.PrependPath(). +func genericPrependPath(vfsroot vfs.VirtualDentry, mnt *vfs.Mount, d *dentry, b *fspath.Builder) error { + for { + if mnt == vfsroot.Mount() && &d.vfsd == vfsroot.Dentry() { + return vfs.PrependPathAtVFSRootError{} + } + if &d.vfsd == mnt.Root() { + return nil + } + if d.parent == nil { + return vfs.PrependPathAtNonMountRootError{} + } + b.PrependComponent(d.name) + d = d.parent + } +} diff --git a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go new file mode 100644 index 000000000..546d432c9 --- /dev/null +++ b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go @@ -0,0 +1,38 @@ +// automatically generated by stateify. + +package gofer + +import ( + "gvisor.dev/gvisor/pkg/state" +) + +func (x *dentryList) beforeSave() {} +func (x *dentryList) save(m state.Map) { + x.beforeSave() + m.Save("head", &x.head) + m.Save("tail", &x.tail) +} + +func (x *dentryList) afterLoad() {} +func (x *dentryList) load(m state.Map) { + m.Load("head", &x.head) + m.Load("tail", &x.tail) +} + +func (x *dentryEntry) beforeSave() {} +func (x *dentryEntry) save(m state.Map) { + x.beforeSave() + m.Save("next", &x.next) + m.Save("prev", &x.prev) +} + +func (x *dentryEntry) afterLoad() {} +func (x *dentryEntry) load(m state.Map) { + m.Load("next", &x.next) + m.Load("prev", &x.prev) +} + +func init() { + state.Register("pkg/sentry/fsimpl/gofer.dentryList", (*dentryList)(nil), state.Fns{Save: (*dentryList).save, Load: (*dentryList).load}) + state.Register("pkg/sentry/fsimpl/gofer.dentryEntry", (*dentryEntry)(nil), state.Fns{Save: (*dentryEntry).save, Load: (*dentryEntry).load}) +} diff --git a/pkg/sentry/fsimpl/gofer/gofer_test.go b/pkg/sentry/fsimpl/gofer/gofer_test.go deleted file mode 100644 index adff39490..000000000 --- a/pkg/sentry/fsimpl/gofer/gofer_test.go +++ /dev/null @@ -1,63 +0,0 @@ -// Copyright 2020 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package gofer - -import ( - "sync/atomic" - "testing" - - "gvisor.dev/gvisor/pkg/p9" - "gvisor.dev/gvisor/pkg/sentry/contexttest" -) - -func TestDestroyIdempotent(t *testing.T) { - fs := filesystem{ - syncableDentries: make(map[*dentry]struct{}), - opts: filesystemOptions{ - // Test relies on no dentry being held in the cache. - maxCachedDentries: 0, - }, - } - - ctx := contexttest.Context(t) - attr := &p9.Attr{ - Mode: p9.ModeRegular, - } - mask := p9.AttrMask{ - Mode: true, - Size: true, - } - parent, err := fs.newDentry(ctx, p9file{}, p9.QID{}, mask, attr) - if err != nil { - t.Fatalf("fs.newDentry(): %v", err) - } - - child, err := fs.newDentry(ctx, p9file{}, p9.QID{}, mask, attr) - if err != nil { - t.Fatalf("fs.newDentry(): %v", err) - } - parent.cacheNewChildLocked(child, "child") - - child.checkCachingLocked() - if got := atomic.LoadInt64(&child.refs); got != -1 { - t.Fatalf("child.refs=%d, want: -1", got) - } - // Parent will also be destroyed when child reference is removed. - if got := atomic.LoadInt64(&parent.refs); got != -1 { - t.Fatalf("parent.refs=%d, want: -1", got) - } - child.checkCachingLocked() - child.checkCachingLocked() -} |