fix: panic occurring when the program execution fails (#60)

* fix: panic occurring when the program execution fails

cmd/capture.go

@@ -50,6 +50,7 @@ by passing the function name symbol and the binary args.
 
 		opts := captor.CaptureOptions{
 			CommandOutput: commandOutput,
+			CommandError:  commandError,
 			LibbpfOutput:  libbpfOutput,
 			Interval:      dumpInterval,
 		}

internal/executor/exec.go

@@ -3,6 +3,7 @@ package executor
 import (
 	"bufio"
 	"fmt"
+	"os"
 	"os/exec"
 	"sync"
 )
@@ -11,15 +12,19 @@ import (
 // The cmdOutput argument is used to print the command output.
 func Run(cmd []string, cmdOutput, cmdError bool, wg *sync.WaitGroup, outputCh, errorCh chan<- string) {
 	defer func() {
+		close(outputCh)
+		close(errorCh)
 		wg.Done()
 	}()
 
 	command := exec.Command(cmd[0], cmd[1:]...)
 	stdout, _ := command.StdoutPipe()
 	stderr, _ := command.StderrPipe()
 
-	//command.Wait()
-	command.Start()
+	if err := command.Start(); err != nil {
+		fmt.Fprintf(os.Stderr, "command execution error: %v\n", err)
+		return
+	}
 
 	go func() {
 		if cmdOutput {
@@ -43,8 +48,6 @@ func Run(cmd []string, cmdOutput, cmdError bool, wg *sync.WaitGroup, outputCh, e
 	}()
 
 	command.Wait()
-	close(outputCh)
-	close(errorCh)
 }
 
 func Build(packagePath, outputFile string) (string, error) {

tests/integration.txtar

@@ -29,6 +29,12 @@ cmp profile.json expected-profile.json
 exec harpoon capture -h
 stdout 'Usage:'
 
+# test it doesn't panic when the file is not executable
+exec chmod -x bin/example-app
+exec harpoon capture -e -c -f main.main -- ./bin/example-app
+stderr 'command execution error: fork/exec .* permission denied'
+exec chmod +x bin/example-app
+
 # setting up test application
 exists bin/example-app
 # this must be done within the testscript environment