1 files changed, 37 insertions, 8 deletions
diff --git a/compiler_wrapper/env.go b/compiler_wrapper/env.go
index 40bc2e41..bbf3ec45 100644
--- a/compiler_wrapper/env.go
+++ b/compiler_wrapper/env.go
@@ -17,9 +17,10 @@ type env interface {
 	getenv(key string) string
 	environ() []string
 	getwd() string
+	stdin() io.Reader
 	stdout() io.Writer
 	stderr() io.Writer
-	run(cmd *command, stdout io.Writer, stderr io.Writer) error
+	run(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error
 	exec(cmd *command) error
 }
 
@@ -49,6 +50,10 @@ func (env *processEnv) getwd() string {
 	return env.wd
 }
 
+func (env *processEnv) stdin() io.Reader {
+	return os.Stdin
+}
+
 func (env *processEnv) stdout() io.Writer {
 	return os.Stdout
 }
@@ -62,16 +67,36 @@ func (env *processEnv) exec(cmd *command) error {
 	return syscall.Exec(execCmd.Path, execCmd.Args, execCmd.Env)
 }
 
-func (env *processEnv) run(cmd *command, stdout io.Writer, stderr io.Writer) error {
+func (env *processEnv) run(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
 	execCmd := newExecCmd(env, cmd)
+	execCmd.Stdin = stdin
 	execCmd.Stdout = stdout
 	execCmd.Stderr = stderr
+	_, stdinIsFile := stdin.(*os.File)
+	_, stdinIsBytesReader := stdin.(*bytes.Reader)
+	if stdin != nil && !stdinIsFile && !stdinIsBytesReader {
+		// We can't use execCmd.Run() here as that blocks if stdin blocks,
+		// even if the underlying process has already terminated. We care
+		// especially about the case when stdin is an io.TeeReader for os.Stdin.
+		// See https://github.com/golang/go/issues/7990 for more details.
+		if err := execCmd.Start(); err != nil {
+			return err
+		}
+		if _, err := execCmd.Process.Wait(); err != nil {
+			return err
+		}
+		// Closing Stdin here as we didn't wait for the read to finish via
+		// execCmd.Wait to prevent race conditions.
+		os.Stdin.Close()
+		return nil
+	}
 	return execCmd.Run()
 }
 
 type commandRecordingEnv struct {
 	env
-	cmdResults []*commandResult
+	stdinReader io.Reader
+	cmdResults  []*commandResult
 }
 type commandResult struct {
 	Cmd      *command `json:"cmd"`
@@ -82,16 +107,20 @@ type commandResult struct {
 
 var _ env = (*commandRecordingEnv)(nil)
 
+func (env *commandRecordingEnv) stdin() io.Reader {
+	return env.stdinReader
+}
+
 func (env *commandRecordingEnv) exec(cmd *command) error {
 	// Note: We treat exec the same as run so that we can do work
 	// after the call.
-	return env.run(cmd, env.stdout(), env.stderr())
+	return env.run(cmd, env.stdin(), env.stdout(), env.stderr())
 }
 
-func (env *commandRecordingEnv) run(cmd *command, stdout io.Writer, stderr io.Writer) error {
+func (env *commandRecordingEnv) run(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
 	stdoutBuffer := &bytes.Buffer{}
 	stderrBuffer := &bytes.Buffer{}
-	err := env.env.run(cmd, io.MultiWriter(stdout, stdoutBuffer), io.MultiWriter(stderr, stderrBuffer))
+	err := env.env.run(cmd, stdin, io.MultiWriter(stdout, stdoutBuffer), io.MultiWriter(stderr, stderrBuffer))
 	if exitCode, ok := getExitCode(err); ok {
 		env.cmdResults = append(env.cmdResults, &commandResult{
 			Cmd:      cmd,
@@ -114,9 +143,9 @@ func (env *printingEnv) exec(cmd *command) error {
 	return env.env.exec(cmd)
 }
 
-func (env *printingEnv) run(cmd *command, stdout io.Writer, stderr io.Writer) error {
+func (env *printingEnv) run(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
 	printCmd(env, cmd)
-	return env.env.run(cmd, stdout, stderr)
+	return env.env.run(cmd, stdin, stdout, stderr)
 }
 
 func printCmd(env env, cmd *command) {