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unix: add RecvmsgBuffers and SendmsgBuffers
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Fixes golang/go#52885

Change-Id: I04b5be1ac9543a3791ebc4cd59b9e35e958e0ba2
Reviewed-on: https://go-review.googlesource.com/c/sys/+/412497
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
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ianlancetaylor authored and gopherbot committed Jun 24, 2022
1 parent 175b2fd commit 87e55d7
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Showing 6 changed files with 206 additions and 73 deletions.
4 changes: 2 additions & 2 deletions unix/syscall_aix.go
View file
Expand Up @@ -217,12 +217,12 @@ func Accept(fd int) (nfd int, sa Sockaddr, err error) {
return
}

func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
// Recvmsg not implemented on AIX
return -1, -1, -1, ENOSYS
}

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
// SendmsgN not implemented on AIX
return -1, ENOSYS
}
Expand Down
46 changes: 23 additions & 23 deletions unix/syscall_bsd.go
View file
Expand Up @@ -325,27 +325,26 @@ func GetsockoptString(fd, level, opt int) (string, error) {
//sys sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
//sys recvmsg(s int, msg *Msghdr, flags int) (n int, err error)

func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(rsa))
msg.Namelen = uint32(SizeofSockaddrAny)
var iov Iovec
if len(p) > 0 {
iov.Base = (*byte)(unsafe.Pointer(&p[0]))
iov.SetLen(len(p))
}
var dummy byte
if len(oob) > 0 {
// receive at least one normal byte
if len(p) == 0 {
iov.Base = &dummy
iov.SetLen(1)
if emptyIovecs(iov) {
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
iov = iova[:]
}
msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = recvmsg(fd, &msg, flags); err != nil {
return
}
Expand All @@ -356,31 +355,32 @@ func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn

//sys sendmsg(s int, msg *Msghdr, flags int) (n int, err error)

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(ptr))
msg.Namelen = uint32(salen)
var iov Iovec
if len(p) > 0 {
iov.Base = (*byte)(unsafe.Pointer(&p[0]))
iov.SetLen(len(p))
}
var dummy byte
var empty bool
if len(oob) > 0 {
// send at least one normal byte
if len(p) == 0 {
iov.Base = &dummy
iov.SetLen(1)
empty := emptyIovecs(iov)
if empty {
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
iov = iova[:]
}
msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = sendmsg(fd, &msg, flags); err != nil {
return 0, err
}
if len(oob) > 0 && len(p) == 0 {
if len(oob) > 0 && empty {
n = 0
}
return n, nil
Expand Down
45 changes: 22 additions & 23 deletions unix/syscall_linux.go
View file
Expand Up @@ -1499,34 +1499,33 @@ func KeyctlRestrictKeyring(ringid int, keyType string, restriction string) error
//sys keyctlRestrictKeyringByType(cmd int, arg2 int, keyType string, restriction string) (err error) = SYS_KEYCTL
//sys keyctlRestrictKeyring(cmd int, arg2 int) (err error) = SYS_KEYCTL

func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(rsa))
msg.Namelen = uint32(SizeofSockaddrAny)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
if len(oob) > 0 {
if len(p) == 0 {
if emptyIovecs(iov) {
var sockType int
sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
if err != nil {
return
}
// receive at least one normal byte
if sockType != SOCK_DGRAM {
iov.Base = &dummy
iov.SetLen(1)
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
iov = iova[:]
}
}
msg.Control = &oob[0]
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = recvmsg(fd, &msg, flags); err != nil {
return
}
Expand All @@ -1535,38 +1534,38 @@ func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn
return
}

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
var msg Msghdr
msg.Name = (*byte)(ptr)
msg.Namelen = uint32(salen)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
var empty bool
if len(oob) > 0 {
if len(p) == 0 {
empty := emptyIovecs(iov)
if empty {
var sockType int
sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
if err != nil {
return 0, err
}
// send at least one normal byte
if sockType != SOCK_DGRAM {
iov.Base = &dummy
iov.SetLen(1)
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
}
}
msg.Control = &oob[0]
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = sendmsg(fd, &msg, flags); err != nil {
return 0, err
}
if len(oob) > 0 && len(p) == 0 {
if len(oob) > 0 && empty {
n = 0
}
return n, nil
Expand Down
46 changes: 23 additions & 23 deletions unix/syscall_solaris.go
View file
Expand Up @@ -451,26 +451,25 @@ func Accept(fd int) (nfd int, sa Sockaddr, err error) {

//sys recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_recvmsg

func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(rsa))
msg.Namelen = uint32(SizeofSockaddrAny)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
if len(oob) > 0 {
// receive at least one normal byte
if len(p) == 0 {
iov.Base = &dummy
iov.SetLen(1)
if emptyIovecs(iov) {
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
iov = iova[:]
}
msg.Accrightslen = int32(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = recvmsg(fd, &msg, flags); n == -1 {
return
}
Expand All @@ -480,30 +479,31 @@ func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn

//sys sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_sendmsg

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(ptr))
msg.Namelen = uint32(salen)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
var empty bool
if len(oob) > 0 {
// send at least one normal byte
if len(p) == 0 {
iov.Base = &dummy
iov.SetLen(1)
empty = emptyIovecs(iov)
if empty {
var iova [1]Iovec
iova[0].Base = &dummy
iova[0].SetLen(1)
iov = iova[:]
}
msg.Accrightslen = int32(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if len(iov) > 0 {
msg.Iov = &iov[0]
msg.SetIovlen(len(iov))
}
if n, err = sendmsg(fd, &msg, flags); err != nil {
return 0, err
}
if len(oob) > 0 && len(p) == 0 {
if len(oob) > 0 && empty {
n = 0
}
return n, nil
Expand Down
74 changes: 72 additions & 2 deletions unix/syscall_unix.go
View file
Expand Up @@ -338,21 +338,81 @@ func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, err error) {
}

func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
var iov [1]Iovec
if len(p) > 0 {
iov[0].Base = &p[0]
iov[0].SetLen(len(p))
}
var rsa RawSockaddrAny
n, oobn, recvflags, err = recvmsgRaw(fd, p, oob, flags, &rsa)
n, oobn, recvflags, err = recvmsgRaw(fd, iov[:], oob, flags, &rsa)
// source address is only specified if the socket is unconnected
if rsa.Addr.Family != AF_UNSPEC {
from, err = anyToSockaddr(fd, &rsa)
}
return
}

// RecvmsgBuffers receives a message from a socket using the recvmsg
// system call. The flags are passed to recvmsg. Any non-control data
// read is scattered into the buffers slices. The results are:
// - n is the number of non-control data read into bufs
// - oobn is the number of control data read into oob; this may be interpreted using [ParseSocketControlMessage]
// - recvflags is flags returned by recvmsg
// - from is the address of the sender
func RecvmsgBuffers(fd int, buffers [][]byte, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
iov := make([]Iovec, len(buffers))
for i := range buffers {
if len(buffers[i]) > 0 {
iov[i].Base = &buffers[i][0]
iov[i].SetLen(len(buffers[i]))
} else {
iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
}
}
var rsa RawSockaddrAny
n, oobn, recvflags, err = recvmsgRaw(fd, iov, oob, flags, &rsa)
if err == nil && rsa.Addr.Family != AF_UNSPEC {
from, err = anyToSockaddr(fd, &rsa)
}
return
}

func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
_, err = SendmsgN(fd, p, oob, to, flags)
return
}

func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
var iov [1]Iovec
if len(p) > 0 {
iov[0].Base = &p[0]
iov[0].SetLen(len(p))
}
var ptr unsafe.Pointer
var salen _Socklen
if to != nil {
ptr, salen, err = to.sockaddr()
if err != nil {
return 0, err
}
}
return sendmsgN(fd, iov[:], oob, ptr, salen, flags)
}

// SendmsgBuffers sends a message on a socket to an address using the sendmsg
// system call. The flags are passed to sendmsg. Any non-control data written
// is gathered from buffers. The function returns the number of bytes written
// to the socket.
func SendmsgBuffers(fd int, buffers [][]byte, oob []byte, to Sockaddr, flags int) (n int, err error) {
iov := make([]Iovec, len(buffers))
for i := range buffers {
if len(buffers[i]) > 0 {
iov[i].Base = &buffers[i][0]
iov[i].SetLen(len(buffers[i]))
} else {
iov[i].Base = (*byte)(unsafe.Pointer(&_zero))
}
}
var ptr unsafe.Pointer
var salen _Socklen
if to != nil {
Expand All @@ -361,7 +421,7 @@ func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error)
return 0, err
}
}
return sendmsgN(fd, p, oob, ptr, salen, flags)
return sendmsgN(fd, iov, oob, ptr, salen, flags)
}

func Send(s int, buf []byte, flags int) (err error) {
Expand Down Expand Up @@ -484,3 +544,13 @@ func Lutimes(path string, tv []Timeval) error {
}
return UtimesNanoAt(AT_FDCWD, path, ts, AT_SYMLINK_NOFOLLOW)
}

// emptyIovec reports whether there are no bytes in the slice of Iovec.
func emptyIovecs(iov []Iovec) bool {
for i := range iov {
if iov[i].Len > 0 {
return false
}
}
return true
}

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