util: Add 'luks' to the FileTypeInfo

Add the ability to detect a luks encrypted device.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/util/virstoragefile.c

@@ -63,7 +63,7 @@ VIR_ENUM_IMPL(virStorageFileFormat,
               "cloop", "dmg", "iso",
               "vpc", "vdi",
               /* Not direct file formats, but used for various drivers */
-              "fat", "vhd", "ploop",
+              "fat", "vhd", "ploop", "luks",
               /* Formats with backing file below here */
               "cow", "qcow", "qcow2", "qed", "vmdk")
 
@@ -189,6 +189,13 @@ qedGetBackingStore(char **, int *, const char *, size_t);
 #define PLOOP_IMAGE_SIZE_OFFSET 36
 #define PLOOP_SIZE_MULTIPLIER 512
 
+#define LUKS_HDR_MAGIC_LEN 6
+#define LUKS_HDR_VERSION_LEN 2
+
+/* Format described by qemu commit id '3e308f20e' */
+#define LUKS_HDR_VERSION_OFFSET LUKS_HDR_MAGIC_LEN
+
+
 static struct FileTypeInfo const fileTypeInfo[] = {
     [VIR_STORAGE_FILE_NONE] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
                                 -1, 0, {0}, 0, 0, 0, 0, NULL, NULL },
@@ -244,6 +251,13 @@ static struct FileTypeInfo const fileTypeInfo[] = {
                                  -2, 0, {0}, PLOOP_IMAGE_SIZE_OFFSET, 0,
                                  PLOOP_SIZE_MULTIPLIER, -1, NULL, NULL },
 
+    /* Magic is 'L','U','K','S', 0xBA, 0xBE
+     * Set sizeOffset = -1 and let hypervisor handle */
+    [VIR_STORAGE_FILE_LUKS] = {
+        0, "\x4c\x55\x4b\x53\xba\xbe", NULL,
+        LV_BIG_ENDIAN, LUKS_HDR_VERSION_OFFSET, 2, {1},
+        -1, 0, 0, -1, NULL, NULL
+    },
     /* All formats with a backing store probe below here */
     [VIR_STORAGE_FILE_COW] = {
         0, "OOOM", NULL,
@@ -626,7 +640,7 @@ virStorageFileMatchesVersion(int format,
                              char *buf,
                              size_t buflen)
 {
-    int version;
+    int version = 0;
     size_t i;
 
     /* Validate version number info */
@@ -843,6 +857,12 @@ virStorageFileGetMetadataInternal(virStorageSourcePtr meta,
             goto cleanup;
     }
 
+    if (meta->format == VIR_STORAGE_FILE_LUKS) {
+        /* By definition, this is encrypted */
+        if (!meta->encryption && VIR_ALLOC(meta->encryption) < 0)
+            goto cleanup;
+    }
+
     VIR_FREE(meta->backingStoreRaw);
     if (fileTypeInfo[meta->format].getBackingStore != NULL) {
         int store = fileTypeInfo[meta->format].getBackingStore(&meta->backingStoreRaw,

src/util/virstoragefile.h

@@ -74,6 +74,7 @@ typedef enum {
     VIR_STORAGE_FILE_FAT,
     VIR_STORAGE_FILE_VHD,
     VIR_STORAGE_FILE_PLOOP,
+    VIR_STORAGE_FILE_LUKS,
 
     /* Not a format, but a marker: all formats below this point have
      * libvirt support for following a backing chain */