net: let OS-specific AddFD routine wake up polling thread.

With gccgo some operating systems require using select rather
than epoll or kevent.  Using select means that we have to wake
up the polling thread each time we add a new file descriptor.
This implements that in the generic code rather than adding
another wakeup channel, even though nothing in the current net
package uses the capability.

R=rsc, iant2
CC=golang-dev
https://golang.org/cl/4284069

5 files changed, 19 insertions, 15 deletions

diff --git a/src/pkg/net/fd.go b/src/pkg/net/fd.go
index fa163ebe07..df4dbce1cf 100644
--- a/src/pkg/net/fd.go
+++ b/src/pkg/net/fd.go
@@ -122,9 +122,13 @@ func (s *pollServer) AddFD(fd *netFD, mode int) {
 		doWakeup = true
 	}
 
-	if err := s.poll.AddFD(intfd, mode, false); err != nil {
+	wake, err := s.poll.AddFD(intfd, mode, false)
+	if err != nil {
 		panic("pollServer AddFD " + err.String())
 	}
+	if wake {
+		doWakeup = true
+	}
 
 	s.Unlock()
 
diff --git a/src/pkg/net/fd_darwin.go b/src/pkg/net/fd_darwin.go
index 6ed196324d..00a049bfd1 100644
--- a/src/pkg/net/fd_darwin.go
+++ b/src/pkg/net/fd_darwin.go
@@ -31,7 +31,7 @@ func newpollster() (p *pollster, err os.Error) {
 	return p, nil
 }
 
-func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
+func (p *pollster) AddFD(fd int, mode int, repeat bool) (bool, os.Error) {
 	// pollServer is locked.
 
 	var kmode int
@@ -53,15 +53,15 @@ func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
 
 	n, e := syscall.Kevent(p.kq, p.kbuf[0:], p.kbuf[0:], nil)
 	if e != 0 {
-		return os.NewSyscallError("kevent", e)
+		return false, os.NewSyscallError("kevent", e)
 	}
 	if n != 1 || (ev.Flags&syscall.EV_ERROR) == 0 || int(ev.Ident) != fd || int(ev.Filter) != kmode {
-		return os.ErrorString("kqueue phase error")
+		return false, os.ErrorString("kqueue phase error")
 	}
 	if ev.Data != 0 {
-		return os.Errno(int(ev.Data))
+		return false, os.Errno(int(ev.Data))
 	}
-	return nil
+	return false, nil
 }
 
 func (p *pollster) DelFD(fd int, mode int) {
diff --git a/src/pkg/net/fd_freebsd.go b/src/pkg/net/fd_freebsd.go
index feea92588a..e50883e940 100644
--- a/src/pkg/net/fd_freebsd.go
+++ b/src/pkg/net/fd_freebsd.go
@@ -31,7 +31,7 @@ func newpollster() (p *pollster, err os.Error) {
 	return p, nil
 }
 
-func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
+func (p *pollster) AddFD(fd int, mode int, repeat bool) (bool, os.Error) {
 	// pollServer is locked.
 
 	var kmode int
@@ -51,15 +51,15 @@ func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
 
 	n, e := syscall.Kevent(p.kq, p.kbuf[:], nil, nil)
 	if e != 0 {
-		return os.NewSyscallError("kevent", e)
+		return false, os.NewSyscallError("kevent", e)
 	}
 	if n != 1 || (ev.Flags&syscall.EV_ERROR) == 0 || int(ev.Ident) != fd || int(ev.Filter) != kmode {
-		return os.NewSyscallError("kqueue phase error", e)
+		return false, os.NewSyscallError("kqueue phase error", e)
 	}
 	if ev.Data != 0 {
-		return os.Errno(int(ev.Data))
+		return false, os.Errno(int(ev.Data))
 	}
-	return nil
+	return false, nil
 }
 
 func (p *pollster) DelFD(fd int, mode int) {
diff --git a/src/pkg/net/fd_linux.go b/src/pkg/net/fd_linux.go
index 69fbc02c0c..dcf65c014d 100644
--- a/src/pkg/net/fd_linux.go
+++ b/src/pkg/net/fd_linux.go
@@ -47,7 +47,7 @@ func newpollster() (p *pollster, err os.Error) {
 	return p, nil
 }
 
-func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
+func (p *pollster) AddFD(fd int, mode int, repeat bool) (bool, os.Error) {
 	// pollServer is locked.
 
 	var already bool
@@ -69,10 +69,10 @@ func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
 		op = syscall.EPOLL_CTL_ADD
 	}
 	if e := syscall.EpollCtl(p.epfd, op, fd, &p.ctlEvent); e != 0 {
-		return os.NewSyscallError("epoll_ctl", e)
+		return false, os.NewSyscallError("epoll_ctl", e)
 	}
 	p.events[fd] = p.ctlEvent.Events
-	return nil
+	return false, nil
 }
 
 func (p *pollster) StopWaiting(fd int, bits uint) {
diff --git a/src/pkg/net/newpollserver.go b/src/pkg/net/newpollserver.go
index 820e70b46f..fff54dba71 100644
--- a/src/pkg/net/newpollserver.go
+++ b/src/pkg/net/newpollserver.go
@@ -31,7 +31,7 @@ func newPollServer() (s *pollServer, err os.Error) {
 	if s.poll, err = newpollster(); err != nil {
 		goto Error
 	}
-	if err = s.poll.AddFD(s.pr.Fd(), 'r', true); err != nil {
+	if _, err = s.poll.AddFD(s.pr.Fd(), 'r', true); err != nil {
 		s.poll.Close()
 		goto Error
 	}