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https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Ayush RanjanandgVisor bot
1bfa2f1d4a
Instead of truncating iovecs when len(iovecs) > MaxReadWriteIov, we should attempt a full write. There are multiple users of hostfd: - tmpfs (when using file backend) - gofer client - hostinet - fsimpl/host These callers use hostfd to implement all read/write operations. Even though read/write syscall semantics allow for short IO, Linux seems to be doing full reads/writes. For compatibility, hostfd should attempt full IO. PiperOrigin-RevId: 582050290
62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
// Copyright 2020 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 hostfd
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import (
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"unsafe"
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"golang.org/x/sys/unix"
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)
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const (
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sizeofIovec = unsafe.Sizeof(unix.Iovec{})
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sizeofMsghdr = unsafe.Sizeof(unix.Msghdr{})
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)
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func iovecsReadWrite(sysno uintptr, fd int32, iovs []unix.Iovec, offset int64, flags uint32) (uintptr, unix.Errno) {
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var total uintptr
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for start := 0; start < len(iovs); start += MaxReadWriteIov {
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last := true
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size := len(iovs) - start
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if size > MaxReadWriteIov {
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last = false
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size = MaxReadWriteIov
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}
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curOff := offset
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if offset >= 0 {
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curOff = offset + int64(total)
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}
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cur, _, e := unix.Syscall6(sysno, uintptr(fd), uintptr((unsafe.Pointer)(&iovs[start])), uintptr(size), uintptr(curOff), 0 /* pos_h */, uintptr(flags))
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if cur > 0 {
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total += cur
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}
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if e != 0 {
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return total, e
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}
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if last {
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break
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}
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// If this was a short read/write, then break.
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var curTotal uint64
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for i := range iovs[start : start+size] {
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curTotal += iovs[i].Len
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}
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if uint64(cur) < curTotal {
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break
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}
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}
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return total, 0
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}
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