feat(shell): use coreutils from u-root

internal/shell/coreutils.go

@@ -0,0 +1,59 @@
+package shell
+
+import (
+	"context"
+
+	"github.com/u-root/u-root/pkg/core"
+	"github.com/u-root/u-root/pkg/core/cat"
+	"github.com/u-root/u-root/pkg/core/chmod"
+	"github.com/u-root/u-root/pkg/core/cp"
+	"github.com/u-root/u-root/pkg/core/find"
+	"github.com/u-root/u-root/pkg/core/ls"
+	"github.com/u-root/u-root/pkg/core/mkdir"
+	"github.com/u-root/u-root/pkg/core/mv"
+	"github.com/u-root/u-root/pkg/core/rm"
+	"github.com/u-root/u-root/pkg/core/touch"
+	"github.com/u-root/u-root/pkg/core/xargs"
+	"mvdan.cc/sh/v3/interp"
+)
+
+var coreUtils = map[string]func() core.Command{
+	"cat":   func() core.Command { return cat.New() },
+	"chmod": func() core.Command { return chmod.New() },
+	"cp":    func() core.Command { return cp.New() },
+	"find":  func() core.Command { return find.New() },
+	"ls":    func() core.Command { return ls.New() },
+	"mkdir": func() core.Command { return mkdir.New() },
+	"mv":    func() core.Command { return mv.New() },
+	"rm":    func() core.Command { return rm.New() },
+	"touch": func() core.Command { return touch.New() },
+	"xargs": func() core.Command { return xargs.New() },
+}
+
+func (s *Shell) coreUtilsHandler() func(next interp.ExecHandlerFunc) interp.ExecHandlerFunc {
+	return func(next interp.ExecHandlerFunc) interp.ExecHandlerFunc {
+		return func(ctx context.Context, args []string) error {
+			if len(args) == 0 {
+				return next(ctx, args)
+			}
+
+			program, programArgs := args[0], args[1:]
+
+			newCoreUtil, ok := coreUtils[program]
+			if !ok {
+				return next(ctx, args)
+			}
+
+			c := interp.HandlerCtx(ctx)
+
+			cmd := newCoreUtil()
+			cmd.SetIO(c.Stdin, c.Stdout, c.Stderr)
+			cmd.SetWorkingDir(c.Dir)
+			cmd.SetLookupEnv(func(key string) (string, bool) {
+				v := c.Env.Get(key)
+				return v.Str, v.Set
+			})
+			return cmd.RunContext(ctx, programArgs...)
+		}
+	}
+}

internal/shell/shell.go

@@ -221,7 +221,7 @@ func (s *Shell) execPOSIX(ctx context.Context, command string) (string, string,
 		interp.Interactive(false),
 		interp.Env(expand.ListEnviron(s.env...)),
 		interp.Dir(s.cwd),
-		interp.ExecHandlers(s.blockHandler()),
+		interp.ExecHandlers(s.blockHandler(), s.coreUtilsHandler()),
 	)
 	if err != nil {
 		return "", "", fmt.Errorf("could not run command: %w", err)