Add timeout flag, for testing. (#188)

* Add timeout flag, for testing.

This will now be used for all test-cases, and will cap runs at two
minutes.  This might be useful to others, but for the moment I struggle
to think of a good purpose!

This closes #186.

* Setup a default context for when nothing was specified

cpm/cpm.go

@@ -43,6 +43,9 @@ var (
 	// It should be handled and expected by callers.
 	ErrBoot = errors.New("BOOT")
 
+	// ErrTimeout is used when a timeout occurs
+	ErrTimeout = errors.New("TIMEOUT")
+
 	// ErrUnimplemented will be used to handle a CP/M binary calling an unimplemented syscall.
 	//
 	// It should be handled and expected by callers.
@@ -110,6 +113,9 @@ type FileCache struct {
 // CPM is the object that holds our emulator state.
 type CPM struct {
 
+	// context for handling timeout
+	context context.Context
+
 	// syscallErr holds any error created by a BIOS or BDOS syscall handler.
 	//
 	// We need this because the handlers are invoked by our OUT-wrapper and they
@@ -274,6 +280,14 @@ func WithHostExec(prefix string) cpmoption {
 	}
 }
 
+// WithContext allows a context to be passed to the evaluator.
+func WithContext(ctx context.Context) cpmoption {
+	return func(c *CPM) error {
+		c.context = ctx
+		return nil
+	}
+}
+
 // New returns a new emulation object.  We support default options,
 // and new defaults may be specified via WithOutputDriver, etc, etc.
 func New(options ...cpmoption) (*CPM, error) {
@@ -573,6 +587,7 @@ func New(options ...cpmoption) (*CPM, error) {
 	tmp := &CPM{
 		BDOSSyscalls: bdos,
 		BIOSSyscalls: bios,
+		context:      context.Background(),
 		ccp:          "ccp", // default
 		dma:          DefaultDMAAddress,
 		drives:       make(map[string]string),
@@ -893,6 +908,17 @@ func (cpm *CPM) Execute(args []string) error {
 	}
 
 	for {
+		//
+		// Check on our timeout since we're here.
+		//
+		select {
+		case <-cpm.context.Done():
+			return ErrTimeout
+
+		default:
+			// nop
+		}
+
 		// Reset the state of any saved error and the halt-flag.
 		cpm.syscallErr = nil
 		cpm.CPU.HALT = false
@@ -908,6 +934,10 @@ func (cpm *CPM) Execute(args []string) error {
 			return ErrHalt
 		}
 
+		if err == ErrTimeout || cpm.syscallErr == ErrTimeout {
+			return ErrTimeout
+		}
+
 		// An unimplemented system-call was encountered.
 		// That's a fatal-error
 		if err == ErrUnimplemented || cpm.syscallErr == ErrUnimplemented {
@@ -1013,6 +1043,15 @@ func (cpm *CPM) In(addr uint8) uint8 {
 // A register and there are far far fewer of them.
 func (cpm *CPM) Out(addr uint8, val uint8) {
 
+	select {
+	case <-cpm.context.Done():
+		cpm.CPU.HALT = true
+		cpm.syscallErr = ErrTimeout
+		return
+	default:
+		// nop
+	}
+
 	if cpm.CPU.HALT {
 		slog.Error("Out() called when CPU is halted",
 			slog.Group("Out",

main.go

@@ -3,13 +3,15 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log/slog"
 	"os"
 	"slices"
 	"sort"
 	"strings"
+	"time"
 
 	cpmccp "github.com/skx/cpmulator/ccp"
 	"github.com/skx/cpmulator/consolein"
@@ -64,6 +66,7 @@ func main() {
 	logPath := flag.String("log-path", "", "Specify the file to write debug logs to.")
 	prnPath := flag.String("prn-path", "print.log", "Specify the file to write printer-output to.")
 	showVersion := flag.Bool("version", false, "Report our version, and exit.")
+	timeout := flag.Int("timeout", 0, "Timeout execution after the given number of seconds")
 	useDirectories := flag.Bool("directories", false, "Use subdirectories on the host computer for CP/M drives.")
 
 	// listing
@@ -214,6 +217,13 @@ func main() {
 		defer logFile.Close()
 	}
 
+	ctx := context.Background()
+	var cancel context.CancelFunc
+	if *timeout != 0 {
+		ctx, cancel = context.WithTimeout(context.Background(), time.Duration(*timeout)*time.Second)
+		defer cancel()
+	}
+
 	// Create our logging handler, using the level we've just setup.
 	log = slog.New(
 		slog.NewJSONHandler(
@@ -230,6 +240,7 @@ func main() {
 		cpm.WithOutputDriver(*output),
 		cpm.WithInputDriver(*input),
 		cpm.WithHostExec(*execPrefix),
+		cpm.WithContext(ctx),
 		cpm.WithCCP(*ccp))
 	if err != nil {
 		fmt.Printf("error creating CPM object: %s\n", err)
@@ -342,13 +353,18 @@ func main() {
 
 			// Deliberate stop of execution
 			if err == cpm.ErrHalt {
-				fmt.Printf("\n")
+				fmt.Printf("\r\n")
 				return
 			}
 
 			// Reboot attempt, also fine
 			if err == cpm.ErrBoot {
-				fmt.Printf("\n")
+				fmt.Printf("\r\n")
+				return
+			}
+
+			if err == cpm.ErrTimeout {
+				fmt.Printf("\r\nThe timeout of %d seconds was exceeded.  Terminating!\r\n", *timeout)
 				return
 			}
 
@@ -402,6 +418,11 @@ func main() {
 				return
 			}
 
+			if err == cpm.ErrTimeout {
+				fmt.Printf("\r\nThe timeout of %d seconds was exceeded.  Terminating!\r\n", *timeout)
+				return
+			}
+
 			fmt.Printf("\nError running CCP: %s\n", err)
 			return
 		}

test/ccp.in

@@ -0,0 +1,2 @@
+A:
+EXIT

test/ccp.pat

@@ -0,0 +1,5 @@
+Console input:file
+Console output:adm-3a
+BIOS:0xFE00
+BDOS:0xFA00
+CCP:ccp

test/run-test.sh

@@ -71,7 +71,7 @@ fi
 #
 export INPUT_FILE="${input}"
 echo " Starting $(date)"
-./cpmulator -input file  -cd ../cpm-dist/ -directories -ccp ccp | ansifilter &> "$output"
+./cpmulator -input file  -cd ../cpm-dist/ -directories -timeout 120 -ccp ccp | ansifilter &> "$output"
 echo " Completed $(date)"
 
 #