cgi: close stdout reader pipe when finished

This causes the child, if still writing, to get an error or
SIGPIPE and most likely exit so our subsequent wait can
finish.

A more guaranteed fix would be putting a time limit on the
child's overall execution, but this fixes the problem
I was having.

Fixes #2059

R=rsc
CC=golang-dev
https://golang.org/cl/4675081

1 files changed, 4 insertions, 2 deletions

diff --git a/src/pkg/exec/exec.go b/src/pkg/exec/exec.go
index 4ddefae24e..3b20f2008c 100644
--- a/src/pkg/exec/exec.go
+++ b/src/pkg/exec/exec.go
@@ -338,7 +338,8 @@ func (c *Cmd) StdinPipe() (io.WriteCloser, os.Error) {
 
 // StdoutPipe returns a pipe that will be connected to the command's
 // standard output when the command starts.
-func (c *Cmd) StdoutPipe() (io.Reader, os.Error) {
+// The pipe will be closed automatically after Wait sees the command exit.
+func (c *Cmd) StdoutPipe() (io.ReadCloser, os.Error) {
 	if c.Stdout != nil {
 		return nil, os.NewError("exec: Stdout already set")
 	}
@@ -357,7 +358,8 @@ func (c *Cmd) StdoutPipe() (io.Reader, os.Error) {
 
 // StderrPipe returns a pipe that will be connected to the command's
 // standard error when the command starts.
-func (c *Cmd) StderrPipe() (io.Reader, os.Error) {
+// The pipe will be closed automatically after Wait sees the command exit.
+func (c *Cmd) StderrPipe() (io.ReadCloser, os.Error) {
 	if c.Stderr != nil {
 		return nil, os.NewError("exec: Stderr already set")
 	}