force our exit trap to always run (for rtnstate commands) (#556)

* add command validation to shellapi.  mock out bash/zsh versions

* implement validate command fn bash and zsh

* test validate command

* change rtnstate commands to always end with a builtin, so we always get our exit trap to run

* simplify the rtnstate modification, don't add the 'wait' (as this is a different problem/feature)

* update schema

waveshell/pkg/utilfn/utilfn.go

@@ -15,9 +15,11 @@ import (
 	mathrand "math/rand"
 	"net/http"
 	"os"
+	"os/exec"
 	"regexp"
 	"sort"
 	"strings"
+	"syscall"
 	"unicode/utf8"
 )
 
@@ -635,3 +637,39 @@ func DetectMimeType(path string) string {
 	}
 	return rtn
 }
+
+func GetCmdExitCode(cmd *exec.Cmd, err error) int {
+	if cmd == nil || cmd.ProcessState == nil {
+		return GetExitCode(err)
+	}
+	status, ok := cmd.ProcessState.Sys().(syscall.WaitStatus)
+	if !ok {
+		return cmd.ProcessState.ExitCode()
+	}
+	signaled := status.Signaled()
+	if signaled {
+		signal := status.Signal()
+		return 128 + int(signal)
+	}
+	exitStatus := status.ExitStatus()
+	return exitStatus
+}
+
+func GetExitCode(err error) int {
+	if err == nil {
+		return 0
+	}
+	if exitErr, ok := err.(*exec.ExitError); ok {
+		return exitErr.ExitCode()
+	} else {
+		return -1
+	}
+}
+
+func GetFirstLine(s string) string {
+	idx := strings.Index(s, "\n")
+	if idx == -1 {
+		return s
+	}
+	return s[0:idx]
+}