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|
package matrix
import (
"os"
"runtime"
"syscall"
"testing"
"github.com/rfjakob/gocryptfs/v2/internal/syscallcompat"
"github.com/rfjakob/gocryptfs/v2/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)
}
}
}
// We used to allocate 18 bytes too much:
// https://github.com/rfjakob/gocryptfs/v2/issues/311
//
// 8110 bytes of plaintext should get us exactly 8192 bytes of ciphertext.
err = file.Truncate(0)
if err != nil {
t.Fatal(err)
}
err = syscallcompat.Fallocate(fd, FALLOC_DEFAULT, 0, 8110)
if err != nil {
t.Fatal(err)
}
nBytes = test_helpers.Du(t, fd)
want = 8192
if nBytes != want {
t.Errorf("Expected %d allocated bytes, have %d", want, nBytes)
}
// 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")
}
}
|
