github.com/bir3/gocompiler@v0.9.2202/src/internal/poll/sendfile_solaris.go (about) 1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package poll 6 7 import "syscall" 8 9 // Not strictly needed, but very helpful for debugging, see issue #10221. 10 // 11 //go:cgo_import_dynamic _ _ "libsendfile.so" 12 //go:cgo_import_dynamic _ _ "libsocket.so" 13 14 // maxSendfileSize is the largest chunk size we ask the kernel to copy 15 // at a time. 16 const maxSendfileSize int = 4 << 20 17 18 // SendFile wraps the sendfile system call. 19 func SendFile(dstFD *FD, src int, pos, remain int64) (int64, error, bool) { 20 if err := dstFD.writeLock(); err != nil { 21 return 0, err, false 22 } 23 defer dstFD.writeUnlock() 24 if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil { 25 return 0, err, false 26 } 27 28 dst := dstFD.Sysfd 29 var ( 30 written int64 31 err error 32 handled = true 33 ) 34 for remain > 0 { 35 n := maxSendfileSize 36 if int64(n) > remain { 37 n = int(remain) 38 } 39 pos1 := pos 40 n, err1 := syscall.Sendfile(dst, src, &pos1, n) 41 if err1 == syscall.EAGAIN || err1 == syscall.EINTR { 42 // partial write may have occurred 43 n = int(pos1 - pos) 44 } 45 if n > 0 { 46 pos += int64(n) 47 written += int64(n) 48 remain -= int64(n) 49 } else if n == 0 && err1 == nil { 50 break 51 } 52 if err1 == syscall.EAGAIN { 53 if err1 = dstFD.pd.waitWrite(dstFD.isFile); err1 == nil { 54 continue 55 } 56 } 57 if err1 == syscall.EINTR { 58 continue 59 } 60 if err1 != nil { 61 // This includes syscall.ENOSYS (no kernel 62 // support) and syscall.EINVAL (fd types which 63 // don't implement sendfile) 64 err = err1 65 handled = false 66 break 67 } 68 } 69 return written, err, handled 70 }