bug: try not to orphan daemon processes

main.go

@@ -1,13 +1,25 @@
 package main
 
 import (
+	"os"
+
 	"github.com/acorn-io/cmd"
 	"github.com/gptscript-ai/gptscript/pkg/cli"
+	"github.com/gptscript-ai/gptscript/pkg/daemon"
+	"github.com/gptscript-ai/gptscript/pkg/mvl"
 
 	// Load all VCS
 	_ "github.com/gptscript-ai/gptscript/pkg/loader/vcs"
 )
 
+var log = mvl.Package()
+
 func main() {
+	if len(os.Args) > 2 && os.Args[1] == "sys.daemon" {
+		if err := daemon.SysDaemon(); err != nil {
+			log.Fatalf("failed running daemon: %v", err)
+		}
+		os.Exit(0)
+	}
 	cmd.Main(cli.New())
 }

pkg/daemon/daemon.go

@@ -0,0 +1,24 @@
+package daemon
+
+import (
+	"context"
+	"io"
+	"os"
+	"os/exec"
+)
+
+func SysDaemon() error {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	go func() {
+		_, _ = io.ReadAll(os.Stdin)
+		cancel()
+	}()
+
+	cmd := exec.CommandContext(ctx, os.Args[2], os.Args[3:]...)
+	cmd.Stdin = os.Stdin
+	cmd.Stderr = os.Stderr
+	cmd.Stdin = os.Stdin
+	return cmd.Run()
+}

pkg/engine/daemon.go

@@ -131,6 +131,10 @@ func (e *Engine) startDaemon(_ context.Context, tool types.Tool) (string, error)
 		return "", err
 	}
 
+	// Loop back to gptscript to help with process supervision
+	cmd.Args = append([]string{os.Args[0], "sys.daemon", cmd.Path}, cmd.Args[1:]...)
+	cmd.Path = self()
+
 	cmd.Stdin = r
 	cmd.Stderr = os.Stderr
 	cmd.Stdout = os.Stdout

pkg/engine/self.go

@@ -0,0 +1,27 @@
+//go:build !linux
+
+package engine
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+// Copied from github.com/moby/moby/pkg/reexec d25b0bd7ea6ce17ca085c54d5965eeeb66417e52
+
+func self() string {
+	name := os.Args[0]
+	if filepath.Base(name) == name {
+		if lp, err := exec.LookPath(name); err == nil {
+			return lp
+		}
+	}
+	// handle conversion of relative paths to absolute
+	if absName, err := filepath.Abs(name); err == nil {
+		return absName
+	}
+	// if we couldn't get absolute name, return original
+	// (NOTE: Go only errors on Abs() if os.Getwd fails)
+	return name
+}

pkg/engine/self_linux.go

@@ -0,0 +1,5 @@
+package engine
+
+func self() string {
+	return "/proc/self/exe"
+}