feat: add WASI sock_accept support

Author: rvolosatovs

src/net/error_posix.go

@@ -0,0 +1,24 @@
+// The following is copied and adapted from Go 1.17 official implementation.
+
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris || windows || wasi
+// +build aix darwin dragonfly freebsd js,wasm linux netbsd openbsd solaris windows wasi
+
+package net
+
+import (
+	"os"
+	"syscall"
+)
+
+// wrapSyscallError takes an error and a syscall name. If the error is
+// a syscall.Errno, it wraps it in a os.SyscallError using the syscall name.
+func wrapSyscallError(name string, err error) error {
+	if _, ok := err.(syscall.Errno); ok {
+		err = os.NewSyscallError(name, err)
+	}
+	return err
+}

src/net/file.go

@@ -0,0 +1,31 @@
+//go:build wasi
+// +build wasi
+
+// The following is copied from Go 1.17 official implementation.
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"os"
+)
+
+type fileAddr string
+
+func (fileAddr) Network() string  { return "file+net" }
+func (f fileAddr) String() string { return string(f) }
+
+// FileListener returns a copy of the network listener corresponding
+// to the open file f.
+// It is the caller's responsibility to close ln when finished.
+// Closing ln does not affect f, and closing f does not affect ln.
+func FileListener(f *os.File) (ln Listener, err error) {
+	ln, err = fileListener(f)
+	if err != nil {
+		err = &OpError{Op: "file", Net: "file+net", Source: nil, Addr: fileAddr(f.Name()), Err: err}
+	}
+	return
+}

src/net/file_wasi.go

@@ -0,0 +1,80 @@
+//go:build wasi
+// +build wasi
+
+package net
+
+import (
+	"io"
+	"os"
+	"syscall"
+	"time"
+)
+
+type conn struct {
+	*os.File
+}
+
+// Read implements the Conn Read method.
+func (c *conn) Read(b []byte) (int, error) {
+	n, err := c.File.Read(b)
+	if err != nil && err != io.EOF {
+		return 0, &OpError{Op: "read", Net: "file+net", Source: nil, Addr: nil, Err: err}
+	}
+	return n, err
+}
+
+// Write implements the Conn Write method.
+func (c *conn) Write(b []byte) (int, error) {
+	n, err := c.File.Write(b)
+	if err != nil {
+		return 0, &OpError{Op: "write", Net: "file+net", Source: nil, Addr: nil, Err: err}
+	}
+	return n, err
+}
+
+// LocalAddr implements the Conn LocalAddr method.
+func (*conn) LocalAddr() Addr {
+	return nil
+}
+
+// RemoteAddr implements the Conn RemoteAddr method.
+func (*conn) RemoteAddr() Addr {
+	return nil
+}
+
+// SetDeadline implements the Conn SetDeadline method.
+func (*conn) SetDeadline(t time.Time) error {
+	return ErrNotImplemented
+}
+
+// SetReadDeadline implements the Conn SetReadDeadline method.
+func (*conn) SetReadDeadline(t time.Time) error {
+	return ErrNotImplemented
+}
+
+// SetWriteDeadline implements the Conn SetWriteDeadline method.
+func (*conn) SetWriteDeadline(t time.Time) error {
+	return ErrNotImplemented
+}
+
+type listener struct {
+	*os.File
+}
+
+// Accept implements the Listener Accept method.
+func (l *listener) Accept() (Conn, error) {
+	fd, err := syscall.SockAccept(int(l.File.Fd()), 0)
+	if err != nil {
+		return nil, wrapSyscallError("sock_accept", err)
+	}
+	return &conn{File: os.NewFile(uintptr(fd), "conn")}, nil
+}
+
+// Addr implements the Listener Addr method.
+func (*listener) Addr() Addr {
+	return nil
+}
+
+func fileListener(f *os.File) (Listener, error) {
+	return &listener{File: f}, nil
+}

src/net/net.go

@@ -81,10 +81,6 @@ type Conn interface {
 	SetWriteDeadline(t time.Time) error
 }
 
-type conn struct {
-	//
-}
-
 // A Listener is a generic network listener for stream-oriented protocols.
 //
 // Multiple goroutines may invoke methods on a Listener simultaneously.

src/net/tcpsock.go

@@ -2,9 +2,7 @@ package net
 
 // TCPConn is an implementation of the Conn interface for TCP network
 // connections.
-type TCPConn struct {
-	conn
-}
+type TCPConn struct{}
 
 func (c *TCPConn) CloseWrite() error {
 	return &OpError{"close", "", nil, nil, ErrNotImplemented}

src/syscall/syscall_libc_wasi.go

@@ -4,8 +4,9 @@
 package syscall
 
 import (
-	"internal/itoa"
 	"unsafe"
+
+	"internal/itoa"
 )
 
 // https://github.com/WebAssembly/wasi-libc/blob/main/expected/wasm32-wasi/predefined-macros.txt
@@ -50,21 +51,29 @@ const (
 )
 
 const (
-	__WASI_OFLAGS_CREAT   = 1
-	__WASI_FDFLAGS_APPEND = 1
-	__WASI_OFLAGS_EXCL    = 4
-	__WASI_OFLAGS_TRUNC   = 8
-	__WASI_FDFLAGS_SYNC   = 16
+	__WASI_OFLAGS_CREAT = 1
+	__WASI_OFLAGS_EXCL  = 4
+	__WASI_OFLAGS_TRUNC = 8
+
+	__WASI_FDFLAGS_APPEND   = 1
+	__WASI_FDFLAGS_DSYNC    = 2
+	__WASI_FDFLAGS_NONBLOCK = 4
+	__WASI_FDFLAGS_RSYNC    = 8
+	__WASI_FDFLAGS_SYNC     = 16
 
 	O_RDONLY = 0x04000000
 	O_WRONLY = 0x10000000
 	O_RDWR   = O_RDONLY | O_WRONLY
 
-	O_CREAT  = __WASI_OFLAGS_CREAT << 12
-	O_TRUNC  = __WASI_OFLAGS_TRUNC << 12
-	O_APPEND = __WASI_FDFLAGS_APPEND
-	O_EXCL   = __WASI_OFLAGS_EXCL << 12
-	O_SYNC   = __WASI_FDFLAGS_SYNC
+	O_CREAT = __WASI_OFLAGS_CREAT << 12
+	O_TRUNC = __WASI_OFLAGS_TRUNC << 12
+	O_EXCL  = __WASI_OFLAGS_EXCL << 12
+
+	O_APPEND   = __WASI_FDFLAGS_APPEND
+	O_DSYNC    = __WASI_FDFLAGS_DSYNC
+	O_NONBLOCK = __WASI_FDFLAGS_NONBLOCK
+	O_RSYNC    = __WASI_FDFLAGS_RSYNC
+	O_SYNC     = __WASI_FDFLAGS_SYNC
 
 	O_CLOEXEC = 0
 
@@ -292,14 +301,33 @@ func Lstat(path string, p *Stat_t) (err error) {
 	return
 }
 
+func SockAccept(fd int, flags int) (nfd int, err error) {
+	var retptr0 __wasi_fd_t
+	if n := sock_accept(__wasi_fd_t(fd), __wasi_fdflags_t(flags), &retptr0); n < 0 {
+		return -1, Errno(n)
+	}
+	return int(retptr0), nil
+}
+
 // int stat(const char *path, struct stat * buf);
 //export stat
 func libc_stat(pathname *byte, ptr unsafe.Pointer) int32
 
-// int fstat(fd int, struct stat * buf);
+// int fstat(int fd, struct stat * buf);
 //export fstat
 func libc_fstat(fd int32, ptr unsafe.Pointer) int32
 
 // int lstat(const char *path, struct stat * buf);
 //export lstat
 func libc_lstat(pathname *byte, ptr unsafe.Pointer) int32
+
+type (
+	__wasi_errno_t = uint16
+
+	__wasi_fd_t      = int32
+	__wasi_fdflags_t = uint16
+)
+
+//go:wasm-module wasi_snapshot_preview1
+//export sock_accept
+func sock_accept(fd __wasi_fd_t, flags __wasi_fdflags_t, retptr0 *__wasi_fd_t) __wasi_errno_t