Source file src/pkg/internal/poll/sendfile_bsd.go

     1	// Copyright 2011 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	// +build dragonfly freebsd
     6	
     7	package poll
     8	
     9	import "syscall"
    10	
    11	// maxSendfileSize is the largest chunk size we ask the kernel to copy
    12	// at a time.
    13	const maxSendfileSize int = 4 << 20
    14	
    15	// SendFile wraps the sendfile system call.
    16	func SendFile(dstFD *FD, src int, pos, remain int64) (int64, error) {
    17		if err := dstFD.writeLock(); err != nil {
    18			return 0, err
    19		}
    20		defer dstFD.writeUnlock()
    21		dst := int(dstFD.Sysfd)
    22		var written int64
    23		var err error
    24		for remain > 0 {
    25			n := maxSendfileSize
    26			if int64(n) > remain {
    27				n = int(remain)
    28			}
    29			pos1 := pos
    30			n, err1 := syscall.Sendfile(dst, src, &pos1, n)
    31			if n > 0 {
    32				pos += int64(n)
    33				written += int64(n)
    34				remain -= int64(n)
    35			} else if n == 0 && err1 == nil {
    36				break
    37			}
    38			if err1 == syscall.EAGAIN {
    39				if err1 = dstFD.pd.waitWrite(dstFD.isFile); err1 == nil {
    40					continue
    41				}
    42			}
    43			if err1 != nil {
    44				// This includes syscall.ENOSYS (no kernel
    45				// support) and syscall.EINVAL (fd types which
    46				// don't implement sendfile)
    47				err = err1
    48				break
    49			}
    50		}
    51		return written, err
    52	}
    53	

View as plain text