From 79143468ea6009a8e6ec87e9ee1333756ba88183 Mon Sep 17 00:00:00 2001
From: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Date: Fri, 8 Nov 2019 22:02:12 +0100
Subject: [PATCH] gdbserial: propagate unhandled signals back to a specific
 thread (#1749)

Instead of just sending unhandled signals back to the process send them
to the specific thread that received them.
This is important because:

1. debugserver does not appear to support the vCont;CXX packet without
specifying a target thread
2. the non-cooperative preemption change in an upcoming version of Go
(1.15?) will require sending signals to a specific thread.

Fixes #1744
---
 pkg/proc/gdbserial/gdbserver.go      | 7 +++++--
 pkg/proc/gdbserial/gdbserver_conn.go | 7 ++++---
 pkg/proc/proc_unix_test.go           | 5 -----
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/pkg/proc/gdbserial/gdbserver.go b/pkg/proc/gdbserial/gdbserver.go
index 39b7fbee..62a01dc4 100644
--- a/pkg/proc/gdbserial/gdbserver.go
+++ b/pkg/proc/gdbserial/gdbserver.go
@@ -355,6 +355,9 @@ func LLDBLaunch(cmd []string, wd string, foreground bool, debugInfoDirs []string
 		if foreground {
 			args = append(args, "--stdio-path", "/dev/tty")
 		}
+		if logflags.LLDBServerOutput() {
+			args = append(args, "-g", "-l", "stdout")
+		}
 		args = append(args, "-F", "-R", fmt.Sprintf("127.0.0.1:%d", listener.Addr().(*net.TCPAddr).Port), "--")
 		args = append(args, cmd...)
 
@@ -657,7 +660,7 @@ func (p *Process) ContinueOnce() (proc.Thread, error) {
 continueLoop:
 	for {
 		tu.Reset()
-		threadID, sig, err = p.conn.resume(sig, &tu)
+		threadID, sig, err = p.conn.resume(sig, threadID, &tu)
 		if err != nil {
 			if _, exited := err.(proc.ErrProcessExited); exited {
 				p.exited = true
@@ -896,7 +899,7 @@ func (p *Process) Restart(pos string) error {
 
 	// for some reason we have to send a vCont;c after a vRun to make rr behave
 	// properly, because that's what gdb does.
-	_, _, err = p.conn.resume(0, nil)
+	_, _, err = p.conn.resume(0, "", nil)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/proc/gdbserial/gdbserver_conn.go b/pkg/proc/gdbserial/gdbserver_conn.go
index fc9f797b..a0921615 100644
--- a/pkg/proc/gdbserial/gdbserver_conn.go
+++ b/pkg/proc/gdbserial/gdbserver_conn.go
@@ -539,14 +539,15 @@ func (conn *gdbConn) writeRegister(threadID string, regnum int, data []byte) err
 }
 
 // resume executes a 'vCont' command on all threads with action 'c' if sig
-// is 0 or 'C' if it isn't.
-func (conn *gdbConn) resume(sig uint8, tu *threadUpdater) (string, uint8, error) {
+// is 0 or 'C' if it isn't. If sig isn't 0 a threadID should be specified as
+// the target of the signal.
+func (conn *gdbConn) resume(sig uint8, threadID string, tu *threadUpdater) (string, uint8, error) {
 	if conn.direction == proc.Forward {
 		conn.outbuf.Reset()
 		if sig == 0 {
 			fmt.Fprint(&conn.outbuf, "$vCont;c")
 		} else {
-			fmt.Fprintf(&conn.outbuf, "$vCont;C%02x", sig)
+			fmt.Fprintf(&conn.outbuf, "$vCont;C%02x:%s;c", sig, threadID)
 		}
 	} else {
 		if err := conn.selectThread('c', "p-1.-1", "resume"); err != nil {
diff --git a/pkg/proc/proc_unix_test.go b/pkg/proc/proc_unix_test.go
index 3d85eea0..881eedfc 100644
--- a/pkg/proc/proc_unix_test.go
+++ b/pkg/proc/proc_unix_test.go
@@ -4,7 +4,6 @@ package proc_test
 
 import (
 	"fmt"
-	"runtime"
 	"syscall"
 	"testing"
 	"time"
@@ -23,10 +22,6 @@ func (npe errIssue419) Error() string {
 }
 
 func TestIssue419(t *testing.T) {
-	if testBackend == "lldb" && runtime.GOOS == "darwin" {
-		// debugserver bug?
-		return
-	}
 	if testBackend == "rr" {
 		return
 	}