mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Andrei VaginandgVisor bot
8ab0848c70
sockets, pipes and other non-seekable file descriptors don't use file.offset, so we don't need to update it. With this change, we will be able to call file operations without locking the file.mu mutex. This is already used for pipes in the splice system call. PiperOrigin-RevId: 253746644
132 lines
4.4 KiB
Go
132 lines
4.4 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package dev
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/sentry/context"
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"gvisor.dev/gvisor/pkg/sentry/fs"
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"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
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"gvisor.dev/gvisor/pkg/sentry/memmap"
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"gvisor.dev/gvisor/pkg/sentry/mm"
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"gvisor.dev/gvisor/pkg/sentry/pgalloc"
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"gvisor.dev/gvisor/pkg/waiter"
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)
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// +stateify savable
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type nullDevice struct {
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fsutil.InodeGenericChecker `state:"nosave"`
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fsutil.InodeNoExtendedAttributes `state:"nosave"`
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fsutil.InodeNoopAllocate `state:"nosave"`
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fsutil.InodeNoopRelease `state:"nosave"`
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fsutil.InodeNoopTruncate `state:"nosave"`
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fsutil.InodeNoopWriteOut `state:"nosave"`
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fsutil.InodeNotDirectory `state:"nosave"`
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fsutil.InodeNotMappable `state:"nosave"`
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fsutil.InodeNotSocket `state:"nosave"`
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fsutil.InodeNotSymlink `state:"nosave"`
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fsutil.InodeVirtual `state:"nosave"`
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fsutil.InodeSimpleAttributes
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}
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var _ fs.InodeOperations = (*nullDevice)(nil)
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func newNullDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *nullDevice {
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n := &nullDevice{
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InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
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}
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return n
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}
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// GetFile implements fs.FileOperations.GetFile.
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func (n *nullDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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flags.Pread = true
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flags.Pwrite = true
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return fs.NewFile(ctx, dirent, flags, &nullFileOperations{}), nil
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}
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// +stateify savable
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type nullFileOperations struct {
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fsutil.FileGenericSeek `state:"nosave"`
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fsutil.FileNoIoctl `state:"nosave"`
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fsutil.FileNoMMap `state:"nosave"`
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fsutil.FileNoSplice `state:"nosave"`
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fsutil.FileNoopFlush `state:"nosave"`
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fsutil.FileNoopFsync `state:"nosave"`
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fsutil.FileNoopRead `state:"nosave"`
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fsutil.FileNoopRelease `state:"nosave"`
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fsutil.FileNoopWrite `state:"nosave"`
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fsutil.FileNotDirReaddir `state:"nosave"`
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fsutil.FileUseInodeUnstableAttr `state:"nosave"`
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waiter.AlwaysReady `state:"nosave"`
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}
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var _ fs.FileOperations = (*nullFileOperations)(nil)
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// +stateify savable
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type zeroDevice struct {
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nullDevice
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}
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var _ fs.InodeOperations = (*zeroDevice)(nil)
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func newZeroDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *zeroDevice {
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zd := &zeroDevice{
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nullDevice: nullDevice{
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InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
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},
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}
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return zd
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}
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// GetFile implements fs.FileOperations.GetFile.
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func (zd *zeroDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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flags.Pread = true
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flags.Pwrite = true
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flags.NonSeekable = true
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return fs.NewFile(ctx, dirent, flags, &zeroFileOperations{}), nil
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}
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// +stateify savable
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type zeroFileOperations struct {
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fsutil.FileGenericSeek `state:"nosave"`
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fsutil.FileNoIoctl `state:"nosave"`
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fsutil.FileNoSplice `state:"nosave"`
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fsutil.FileNoopFlush `state:"nosave"`
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fsutil.FileNoopFsync `state:"nosave"`
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fsutil.FileNoopRelease `state:"nosave"`
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fsutil.FileNoopWrite `state:"nosave"`
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fsutil.FileNotDirReaddir `state:"nosave"`
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fsutil.FileUseInodeUnstableAttr `state:"nosave"`
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waiter.AlwaysReady `state:"nosave"`
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readZeros `state:"nosave"`
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}
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var _ fs.FileOperations = (*zeroFileOperations)(nil)
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// ConfigureMMap implements fs.FileOperations.ConfigureMMap.
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func (*zeroFileOperations) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
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m, err := mm.NewSharedAnonMappable(opts.Length, pgalloc.MemoryFileProviderFromContext(ctx))
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if err != nil {
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return err
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}
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opts.MappingIdentity = m
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opts.Mappable = m
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return nil
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}
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