Fix concurrency issues in Test_runWithTimeout
Use a concurrency-safe writer in runWithTimeout to avoid data races
on the bytes.Buffer passed in during tests.
Bug: 181095653
Fixes: 187149270
Test: Test_runWithTimeout
Test: go test -race ./cmd/run_with_timeout
Change-Id: I57a889765cb9ee7b42983f0906313e0c2d1e414e
diff --git a/cmd/run_with_timeout/run_with_timeout.go b/cmd/run_with_timeout/run_with_timeout.go
index e225872..f2caaab 100644
--- a/cmd/run_with_timeout/run_with_timeout.go
+++ b/cmd/run_with_timeout/run_with_timeout.go
@@ -23,6 +23,7 @@
"io"
"os"
"os/exec"
+ "sync"
"syscall"
"time"
)
@@ -62,10 +63,42 @@
}
}
+// concurrentWriter wraps a writer to make it thread-safe to call Write.
+type concurrentWriter struct {
+ w io.Writer
+ sync.Mutex
+}
+
+// Write writes the data to the wrapped writer with a lock to allow for concurrent calls.
+func (c *concurrentWriter) Write(data []byte) (n int, err error) {
+ c.Lock()
+ defer c.Unlock()
+ if c.w == nil {
+ return 0, nil
+ }
+ return c.w.Write(data)
+}
+
+// Close ends the concurrentWriter, causing future calls to Write to be no-ops. It does not close
+// the underlying writer.
+func (c *concurrentWriter) Close() {
+ c.Lock()
+ defer c.Unlock()
+ c.w = nil
+}
+
func runWithTimeout(command string, args []string, timeout time.Duration, onTimeoutCmdStr string,
stdin io.Reader, stdout, stderr io.Writer) error {
cmd := exec.Command(command, args...)
- cmd.Stdin, cmd.Stdout, cmd.Stderr = stdin, stdout, stderr
+
+ // Wrap the writers in a locking writer so that cmd and onTimeoutCmd don't try to write to
+ // stdout or stderr concurrently.
+ concurrentStdout := &concurrentWriter{w: stdout}
+ concurrentStderr := &concurrentWriter{w: stderr}
+ defer concurrentStdout.Close()
+ defer concurrentStderr.Close()
+
+ cmd.Stdin, cmd.Stdout, cmd.Stderr = stdin, concurrentStdout, concurrentStderr
err := cmd.Start()
if err != nil {
return err
@@ -98,7 +131,7 @@
if onTimeoutCmdStr != "" {
onTimeoutCmd := exec.Command("sh", "-c", onTimeoutCmdStr)
- onTimeoutCmd.Stdin, onTimeoutCmd.Stdout, onTimeoutCmd.Stderr = stdin, stdout, stderr
+ onTimeoutCmd.Stdin, onTimeoutCmd.Stdout, onTimeoutCmd.Stderr = stdin, concurrentStdout, concurrentStderr
onTimeoutCmd.Env = append(os.Environ(), fmt.Sprintf("PID=%d", cmd.Process.Pid))
err := onTimeoutCmd.Run()
if err != nil {