package matrix import ( "os" "runtime" "syscall" "testing" "github.com/rfjakob/gocryptfs/internal/syscallcompat" "github.com/rfjakob/gocryptfs/tests/test_helpers" ) const ( // From man statfs TMPFS_MAGIC = 0x01021994 EXT4_SUPER_MAGIC = 0xef53 ) // isWellKnownFS decides if the backing filesystem is well-known. // The expected allocated sizes are only valid on tmpfs and ext4. btrfs // gives different results, but that's not an error. func isWellKnownFS(fn string) bool { var fs syscall.Statfs_t err := syscall.Statfs(fn, &fs) if err != nil { panic(err) } if fs.Type == EXT4_SUPER_MAGIC || fs.Type == TMPFS_MAGIC { return true } return false } const FALLOC_DEFAULT = 0x00 const FALLOC_FL_KEEP_SIZE = 0x01 func TestFallocate(t *testing.T) { if runtime.GOOS == "darwin" { t.Skipf("OSX does not support fallocate") } fn := test_helpers.DefaultPlainDir + "/fallocate" file, err := os.Create(fn) if err != nil { t.FailNow() } defer file.Close() wellKnown := isWellKnownFS(test_helpers.DefaultCipherDir) fd := int(file.Fd()) nBytes := test_helpers.Du(t, fd) if nBytes != 0 { t.Fatalf("Empty file has %d bytes", nBytes) } // Allocate 30 bytes, keep size // gocryptfs || (0 blocks) // ext4 | d | (1 block) // ^ d = data block err = syscallcompat.Fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 30) if err != nil { t.Error(err) } var want int64 nBytes = test_helpers.Du(t, fd) want = 4096 if nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } test_helpers.VerifySize(t, fn, 0) // Three ciphertext blocks. The middle one should be a file hole. // gocryptfs | h | h | d| (1 block) // ext4 | d | h | d | (2 blocks) // ^ h = file hole // (Note that gocryptfs blocks are slightly bigger than the ext4 blocks, // but the last one is partial) err = file.Truncate(9000) if err != nil { t.Fatal(err) } nBytes = test_helpers.Du(t, fd) want = 2 * 4096 if wellKnown && nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" { t.Errorf("Wrong md5 %s", md5) } // Allocate the whole file space // gocryptfs | h | h | d| (1 block) // ext4 | d | d | d | (3 blocks err = syscallcompat.Fallocate(fd, FALLOC_DEFAULT, 0, 9000) if err != nil { t.Fatal(err) } nBytes = test_helpers.Du(t, fd) want = 3 * 4096 if nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } // Neither apparent size nor content should have changed test_helpers.VerifySize(t, fn, 9000) if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" { t.Errorf("Wrong md5 %s", md5) } // Partial block on the end. The first ext4 block is dirtied by the header. // gocryptfs | h | h | d| (1 block) // ext4 | d | h | d | (2 blocks) file.Truncate(0) file.Truncate(9000) nBytes = test_helpers.Du(t, fd) want = 2 * 4096 if wellKnown && nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } // Allocate 10 bytes in the second block // gocryptfs | h | h | d| (1 block) // ext4 | d | d | d | (3 blocks) syscallcompat.Fallocate(fd, FALLOC_DEFAULT, 5000, 10) nBytes = test_helpers.Du(t, fd) want = 3 * 4096 if wellKnown && nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } // Neither apparent size nor content should have changed test_helpers.VerifySize(t, fn, 9000) if md5 := test_helpers.Md5fn(fn); md5 != "5420afa22f6423a9f59e669540656bb4" { t.Errorf("Wrong md5 %s", md5) } // Grow the file to 4 blocks // gocryptfs | h | h | d |d| (2 blocks) // ext4 | d | d | d | d | (4 blocks) syscallcompat.Fallocate(fd, FALLOC_DEFAULT, 15000, 10) nBytes = test_helpers.Du(t, fd) want = 4 * 4096 if wellKnown && nBytes != want { t.Errorf("Expected %d allocated bytes, have %d", want, nBytes) } test_helpers.VerifySize(t, fn, 15010) if md5 := test_helpers.Md5fn(fn); md5 != "c4c44c7a41ab7798a79d093eb44f99fc" { t.Errorf("Wrong md5 %s", md5) } // Shrinking a file using fallocate should have no effect for _, off := range []int64{0, 10, 2000, 5000} { for _, sz := range []int64{0, 1, 42, 6000} { syscallcompat.Fallocate(fd, FALLOC_DEFAULT, off, sz) test_helpers.VerifySize(t, fn, 15010) if md5 := test_helpers.Md5fn(fn); md5 != "c4c44c7a41ab7798a79d093eb44f99fc" { t.Errorf("Wrong md5 %s", md5) } } } // Cleanup syscall.Unlink(fn) if !wellKnown { // Even though most tests have been executed still, inform the user // that some were disabled t.Skipf("backing fs is not ext4 or tmpfs, skipped some disk-usage checks\n") } }