[SEC-11866] cws-instrumentation: add selftests command (#21445)

[SEC-11866] cws-instrumentation: add selftests command

cmd/cws-instrumentation/subcommands/selftestscmd/selftests.go

@@ -0,0 +1,81 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2016-present Datadog, Inc.
+
+//go:build linux
+
+// Package selftestscmd holds the selftests command of CWS injector
+package selftestscmd
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+type execParams struct {
+	enabled bool
+	path    string
+	args    string
+}
+
+type openParams struct {
+	enabled bool
+	path    string
+}
+
+type selftestsCliParams struct {
+	exec execParams
+	open openParams
+}
+
+// Command returns the commands for the selftests subcommand
+func Command() []*cobra.Command {
+	var params selftestsCliParams
+
+	selftestsCmd := &cobra.Command{
+		Use:   "selftests",
+		Short: "run selftests against the tracer",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var err error
+			if params.exec.enabled {
+				err = errors.Join(err, selftestExec(&params.exec))
+			}
+			if params.open.enabled {
+				err = errors.Join(err, selftestOpen(&params.open))
+			}
+			return err
+		},
+	}
+
+	selftestsCmd.Flags().BoolVar(&params.exec.enabled, "exec", false, "run the exec selftest")
+	selftestsCmd.Flags().StringVar(&params.exec.path, "exec.path", "/usr/bin/date", "path to the file to execute")
+	selftestsCmd.Flags().StringVar(&params.exec.args, "exec.args", "", "arguments to pass to the executable")
+	selftestsCmd.Flags().BoolVar(&params.open.enabled, "open", false, "run the open selftest")
+	selftestsCmd.Flags().StringVar(&params.open.path, "open.path", "/tmp/open.test", "path to the file to open")
+
+	return []*cobra.Command{selftestsCmd}
+}
+
+func selftestExec(params *execParams) error {
+	if params.args != "" {
+		return exec.Command(params.path, strings.Split(params.args, " ")...).Run()
+	}
+	return exec.Command(params.path).Run()
+}
+
+func selftestOpen(params *openParams) error {
+	f, createErr := os.OpenFile(params.path, os.O_CREATE|os.O_EXCL, 0400)
+	if createErr != nil {
+		f, openErr := os.Open(params.path)
+		if openErr != nil {
+			return errors.Join(createErr, openErr)
+		}
+		return f.Close()
+	}
+	return errors.Join(f.Close(), os.Remove(params.path))
+}

cmd/cws-instrumentation/subcommands/tracecmd/trace.go

@@ -11,6 +11,7 @@ package tracecmd
 import (
 	"github.com/spf13/cobra"
 
+	"github.com/DataDog/datadog-agent/cmd/cws-instrumentation/subcommands/selftestscmd"
 	"github.com/DataDog/datadog-agent/pkg/security/ptracer"
 )
 
@@ -58,5 +59,7 @@ func Command() []*cobra.Command {
 	traceCmd.Flags().Int32Var(&params.UID, uid, -1, "uid used to start the tracee")
 	traceCmd.Flags().Int32Var(&params.GID, gid, -1, "gid used to start the tracee")
 
+	traceCmd.AddCommand(selftestscmd.Command()...)
+
 	return []*cobra.Command{traceCmd}
 }