github.com/JimmyHuang454/JLS-go@v0.0.0-20230831150107-90d536585ba0/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) { 20 if err := dstFD.writeLock(); err != nil { 21 return 0, err 22 } 23 defer dstFD.writeUnlock() 24 if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil { 25 return 0, err 26 } 27 28 dst := dstFD.Sysfd 29 var written int64 30 var err error 31 for remain > 0 { 32 n := maxSendfileSize 33 if int64(n) > remain { 34 n = int(remain) 35 } 36 pos1 := pos 37 n, err1 := syscall.Sendfile(dst, src, &pos1, n) 38 if err1 == syscall.EAGAIN || err1 == syscall.EINTR { 39 // partial write may have occurred 40 n = int(pos1 - pos) 41 } 42 if n > 0 { 43 pos += int64(n) 44 written += int64(n) 45 remain -= int64(n) 46 } else if n == 0 && err1 == nil { 47 break 48 } 49 if err1 == syscall.EAGAIN { 50 if err1 = dstFD.pd.waitWrite(dstFD.isFile); err1 == nil { 51 continue 52 } 53 } 54 if err1 == syscall.EINTR { 55 continue 56 } 57 if err1 != nil { 58 // This includes syscall.ENOSYS (no kernel 59 // support) and syscall.EINVAL (fd types which 60 // don't implement sendfile) 61 err = err1 62 break 63 } 64 } 65 return written, err 66 }