Added integration tests for mounting tmpfs with size option enabled.

PiperOrigin-RevId: 444705540

pkg/sentry/fsimpl/tmpfs/tmpfs.go

@@ -202,7 +202,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	var maxSizeInPages uint64
 	if ok {
 		delete(mopts, "size")
-		maxSizeInBytes, err := strconv.ParseUint(maxSizeStr, 10, 64)
+		maxSizeInBytes, err := parseSize(maxSizeStr)
 		if err != nil {
 			ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: invalid size: %q", maxSizeStr)
 			return nil, nil, linuxerr.EINVAL
@@ -944,3 +944,33 @@ func (fd *fileDescription) RemoveXattr(ctx context.Context, name string) error {
 func (*fileDescription) Sync(context.Context) error {
 	return nil
 }
+
+// parseSize converts size in string to an integer bytes.
+// Supported suffixes in string are:K, M, G, T, P, E.
+func parseSize(s string) (uint64, error) {
+	suffix := s[len(s)-1]
+	count := 1
+	switch suffix {
+	case 'e', 'E':
+		count = count << 10
+		fallthrough
+	case 'p', 'P':
+		count = count << 10
+		fallthrough
+	case 't', 'T':
+		count = count << 10
+		fallthrough
+	case 'g', 'G':
+		count = count << 10
+		fallthrough
+	case 'm', 'M':
+		count = count << 10
+		fallthrough
+	case 'k', 'K':
+		count = count << 10
+		s = s[:len(s)-1]
+	}
+	bytes, err := strconv.ParseUint(s, 10, 64)
+	bytes = bytes * uint64(count)
+	return bytes, err
+}

pkg/sentry/fsimpl/tmpfs/tmpfs_test.go

@@ -16,6 +16,7 @@ package tmpfs
 
 import (
 	"fmt"
+	"testing"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/atomicbitops"
@@ -155,3 +156,37 @@ func newPipeFD(ctx context.Context, mode linux.FileMode) (*vfs.FileDescription,
 
 	return fd, cleanup, nil
 }
+
+func TestParseSize(t *testing.T) {
+	var tests = []struct {
+		s         string
+		want      uint64
+		wantError bool
+	}{
+		{"500", 500, false},
+		{"5k", (5 * 1024), false},
+		{"5m", (5 * 1024 * 1024), false},
+		{"5G", (5 * 1024 * 1024 * 1024), false},
+		{"5t", (5 * 1024 * 1024 * 1024 * 1024), false},
+		{"5P", (5 * 1024 * 1024 * 1024 * 1024 * 1024), false},
+		{"5e", (5 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024), false},
+		{"5e3", 0, true},
+	}
+	for _, tt := range tests {
+		testname := fmt.Sprintf("%s", tt.s)
+		t.Run(testname, func(t *testing.T) {
+			size, err := parseSize(tt.s)
+			if tt.wantError && err == nil {
+				t.Errorf("Invalid input: %v parsed", tt.s)
+			}
+			if !tt.wantError {
+				if err != nil {
+					t.Errorf("Couldn't parse size, Error: %v", err)
+				}
+				if size != tt.want {
+					t.Errorf("got: %v, want %v", size, tt.want)
+				}
+			}
+		})
+	}
+}

runsc/boot/fs.go

@@ -67,7 +67,7 @@ const (
 )
 
 // tmpfs has some extra supported options that we must pass through.
-var tmpfsAllowedData = []string{"mode", "uid", "gid"}
+var tmpfsAllowedData = []string{"mode", "size", "uid", "gid"}
 
 func addOverlay(ctx context.Context, lower *fs.Inode, name string, lowerFlags fs.MountSourceFlags) (*fs.Inode, error) {
 	// Upper layer uses the same flags as lower, but it must be read-write.

test/e2e/integration_test.go

@@ -911,3 +911,42 @@ func TestRevalidateSymlinkChain(t *testing.T) {
 		t.Fatalf("Read wrong file, want: %q, got: %q", want, got)
 	}
 }
+
+// TestTmpMountWithSize checks when 'tmpfs' is mounted
+// with size option the limit is not exceeded.
+func TestTmpMountWithSize(t *testing.T) {
+	ctx := context.Background()
+	d := dockerutil.MakeContainer(ctx, t)
+	defer d.CleanUp(ctx)
+
+	opts := dockerutil.RunOpts{
+		Image: "basic/alpine",
+		Mounts: []mount.Mount{
+			{
+				Type:   mount.TypeTmpfs,
+				Target: "/tmp/foo",
+				TmpfsOptions: &mount.TmpfsOptions{
+					SizeBytes: 4096,
+				},
+			},
+		},
+	}
+	if err := d.Create(ctx, opts, "sleep", "1000"); err != nil {
+		t.Fatalf("docker create failed: %v", err)
+	}
+	if err := d.Start(ctx); err != nil {
+		t.Fatalf("docker start failed: %v", err)
+	}
+
+	if _, err := d.Exec(ctx, dockerutil.ExecOpts{}, "/bin/sh", "-c", "echo hello > /tmp/foo/test1.txt"); err != nil {
+		t.Fatalf("docker exec failed: %v", err)
+	}
+	echoOutput, err := d.Exec(ctx, dockerutil.ExecOpts{}, "/bin/sh", "-c", "echo world > /tmp/foo/test2.txt")
+	if err == nil {
+		t.Fatalf("docker exec size check failed: %v", err)
+	}
+	wantErr := "No space left on device"
+	if !strings.Contains(echoOutput, wantErr) {
+		t.Errorf("unexpected echo error:Expected: %v, Got: %v", wantErr, echoOutput)
+	}
+}