Hostpath mount validation

pkg/mcp/toolset/toolset.go

@@ -11,6 +11,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"slices"
+	"strings"
 
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 	"github.com/pkg/sftp"
@@ -109,6 +110,29 @@ func (ts *ToolSet) TranslateHostPath(hostPath string) (string, error) {
 	if !filepath.IsAbs(hostPath) {
 		return "", fmt.Errorf("expected an absolute path, got a relative path: %q", hostPath)
 	}
-	// TODO: make sure that hostPath is mounted
-	return hostPath, nil
+
+	guestPath, isMounted := ts.translateToGuestPath(hostPath)
+	if !isMounted {
+		logrus.Warnf("path %q is not under any mounted directory, using as guest path", hostPath)
+	}
+	return guestPath, nil
+}
+
+func (ts *ToolSet) translateToGuestPath(hostPath string) (string, bool) {
+	for _, mount := range ts.inst.Config.Mounts {
+		location := filepath.Clean(mount.Location)
+		cleanPath := filepath.Clean(hostPath)
+
+		if cleanPath == location {
+			return *mount.MountPoint, true
+		}
+
+		rel, err := filepath.Rel(location, cleanPath)
+		if err == nil && !strings.HasPrefix(rel, "..") && rel != ".." {
+			guestPath := filepath.Join(*mount.MountPoint, rel)
+			return guestPath, true
+		}
+	}
+
+	return hostPath, false
 }

pkg/mcp/toolset/toolset_test.go

@@ -0,0 +1,99 @@
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package toolset
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+
+	"github.com/lima-vm/lima/v2/pkg/limatype"
+)
+
+func TestTranslateHostPath(t *testing.T) {
+	mountPoint1 := "/mnt/home-user"
+	mountPoint2 := "/mnt/tmp"
+
+	tests := []struct {
+		name          string
+		hostPath      string
+		toolSet       ToolSet
+		wantGuestPath string
+		wantErr       bool
+	}{
+		{
+			name:     "file in mounted directory",
+			hostPath: "/home/user/documents/file.txt",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+						},
+					},
+				},
+			},
+			wantGuestPath: "/mnt/home-user/documents/file.txt",
+			wantErr:       false,
+		},
+		{
+			name:     "path outside mount - fallback to guest path",
+			hostPath: "/other/path/file.txt",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+						},
+					},
+				},
+			},
+			wantGuestPath: "/other/path/file.txt",
+			wantErr:       false,
+		},
+		{
+			name:     "similar prefix but not under mount",
+			hostPath: "/home/user2/file.txt",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+						},
+					},
+				},
+			},
+			wantGuestPath: "/home/user2/file.txt",
+			wantErr:       false,
+		},
+		{
+			name:     "multiple mounts",
+			hostPath: "/tmp/myfile",
+			toolSet: ToolSet{
+				inst: &limatype.Instance{
+					Config: &limatype.LimaYAML{
+						Mounts: []limatype.Mount{
+							{Location: "/home/user", MountPoint: &mountPoint1},
+							{Location: "/tmp", MountPoint: &mountPoint2},
+						},
+					},
+				},
+			},
+			wantGuestPath: "/mnt/tmp/myfile",
+			wantErr:       false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := test.toolSet.TranslateHostPath(test.hostPath)
+			if test.wantErr {
+				assert.Assert(t, err != nil)
+			} else {
+				assert.NilError(t, err)
+				assert.Equal(t, test.wantGuestPath, got)
+			}
+		})
+	}
+}