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412f659280
We were accidentally ignoring any error returned by poll.SendFile. Noticed by reading the code. It could only change behavior if the sendfile system call both wrote some bytes and returned an error. Change-Id: I0693d6ec0a30f5a86b78d38793899ca29fb9e156 Reviewed-on: https://go-review.googlesource.com/c/164760 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
86 lines
2.0 KiB
Go
86 lines
2.0 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build dragonfly freebsd solaris
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package net
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import (
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"internal/poll"
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"io"
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"os"
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)
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// sendFile copies the contents of r to c using the sendfile
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// system call to minimize copies.
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//
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// if handled == true, sendFile returns the number of bytes copied and any
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// non-EOF error.
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//
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// if handled == false, sendFile performed no work.
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func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) {
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// FreeBSD, DragonFly and Solaris use 0 as the "until EOF" value.
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// If you pass in more bytes than the file contains, it will
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// loop back to the beginning ad nauseam until it's sent
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// exactly the number of bytes told to. As such, we need to
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// know exactly how many bytes to send.
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var remain int64 = 0
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lr, ok := r.(*io.LimitedReader)
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if ok {
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remain, r = lr.N, lr.R
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if remain <= 0 {
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return 0, nil, true
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}
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}
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f, ok := r.(*os.File)
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if !ok {
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return 0, nil, false
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}
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if remain == 0 {
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fi, err := f.Stat()
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if err != nil {
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return 0, err, false
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}
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remain = fi.Size()
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}
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// The other quirk with FreeBSD/DragonFly/Solaris's sendfile
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// implementation is that it doesn't use the current position
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// of the file -- if you pass it offset 0, it starts from
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// offset 0. There's no way to tell it "start from current
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// position", so we have to manage that explicitly.
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pos, err := f.Seek(0, io.SeekCurrent)
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if err != nil {
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return 0, err, false
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}
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sc, err := f.SyscallConn()
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if err != nil {
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return 0, nil, false
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}
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var werr error
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err = sc.Read(func(fd uintptr) bool {
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written, werr = poll.SendFile(&c.pfd, int(fd), pos, remain)
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return true
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})
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if err == nil {
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err = werr
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}
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if lr != nil {
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lr.N = remain - written
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}
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_, err1 := f.Seek(written, io.SeekCurrent)
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if err1 != nil && err == nil {
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return written, err1, written > 0
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}
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return written, wrapSyscallError("sendfile", err), written > 0
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}
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