[Qemu-devel] [PATCH v4 04/32] blockdev: Move bochs probe into separate file

[Colin Lord]

This puts the bochs probe function into its own separate file as part of
the process of modularizing block drivers. Having the probe functions
separate from the rest of the driver allows us to probe without having
to potentially unnecessarily load the driver.

Signed-off-by: Colin Lord <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
---
 block/Makefile.objs   |  1 +
 block/bochs-probe.c   | 21 ++++++++++++++++++++
 block/bochs.c         | 55 ++-------------------------------------------------
 block/bochs.h         | 40 +++++++++++++++++++++++++++++++++++++
 include/block/probe.h |  6 ++++++
 5 files changed, 70 insertions(+), 53 deletions(-)
 create mode 100644 block/bochs-probe.c
 create mode 100644 block/bochs.h
 create mode 100644 include/block/probe.h

diff --git a/block/Makefile.objs b/block/Makefile.objs
index 2593a2f..9d4be3b 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -24,6 +24,7 @@ block-obj-y += accounting.o dirty-bitmap.o
 block-obj-y += write-threshold.o
 
 block-obj-y += crypto.o
+block-obj-y += bochs-probe.o
 
 common-obj-y += stream.o
 common-obj-y += backup.o
diff --git a/block/bochs-probe.c b/block/bochs-probe.c
new file mode 100644
index 0000000..befe2cf
--- /dev/null
+++ b/block/bochs-probe.c
@@ -0,0 +1,21 @@
+#include "qemu/osdep.h"
+#include "block/block_int.h"
+#include "block/probe.h"
+#include "bochs.h"
+
+int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+    const struct bochs_header *bochs = (const void *)buf;
+
+    if (buf_size < HEADER_SIZE)
+       return 0;
+
+    if (!strcmp(bochs->magic, HEADER_MAGIC) &&
+       !strcmp(bochs->type, REDOLOG_TYPE) &&
+       !strcmp(bochs->subtype, GROWING_TYPE) &&
+       ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
+       (le32_to_cpu(bochs->version) == HEADER_V1)))
+       return 100;
+
+    return 0;
+}
diff --git a/block/bochs.c b/block/bochs.c
index 8c9652e..5c9a696 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -28,45 +28,11 @@
 #include "block/block_int.h"
 #include "qemu/module.h"
 #include "qemu/bswap.h"
+#include "bochs.h"
+#include "block/probe.h"
 
 /**************************************************************/
 
-#define HEADER_MAGIC "Bochs Virtual HD Image"
-#define HEADER_VERSION 0x00020000
-#define HEADER_V1 0x00010000
-#define HEADER_SIZE 512
-
-#define REDOLOG_TYPE "Redolog"
-#define GROWING_TYPE "Growing"
-
-// not allocated: 0xffffffff
-
-// always little-endian
-struct bochs_header {
-    char magic[32];     /* "Bochs Virtual HD Image" */
-    char type[16];      /* "Redolog" */
-    char subtype[16];   /* "Undoable" / "Volatile" / "Growing" */
-    uint32_t version;
-    uint32_t header;    /* size of header */
-
-    uint32_t catalog;   /* num of entries */
-    uint32_t bitmap;    /* bitmap size */
-    uint32_t extent;    /* extent size */
-
-    union {
-        struct {
-            uint32_t reserved;  /* for ??? */
-            uint64_t disk;      /* disk size */
-            char padding[HEADER_SIZE - 64 - 20 - 12];
-        } QEMU_PACKED redolog;
-        struct {
-            uint64_t disk;      /* disk size */
-            char padding[HEADER_SIZE - 64 - 20 - 8];
-        } QEMU_PACKED redolog_v1;
-        char padding[HEADER_SIZE - 64 - 20];
-    } extra;
-} QEMU_PACKED;
-
 typedef struct BDRVBochsState {
     CoMutex lock;
     uint32_t *catalog_bitmap;
@@ -79,23 +45,6 @@ typedef struct BDRVBochsState {
     uint32_t extent_size;
 } BDRVBochsState;
 
-static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
-{
-    const struct bochs_header *bochs = (const void *)buf;
-
-    if (buf_size < HEADER_SIZE)
-       return 0;
-
-    if (!strcmp(bochs->magic, HEADER_MAGIC) &&
-       !strcmp(bochs->type, REDOLOG_TYPE) &&
-       !strcmp(bochs->subtype, GROWING_TYPE) &&
-       ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
-       (le32_to_cpu(bochs->version) == HEADER_V1)))
-       return 100;
-
-    return 0;
-}
-
 static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
                       Error **errp)
 {
diff --git a/block/bochs.h b/block/bochs.h
new file mode 100644
index 0000000..2883f7d
--- /dev/null
+++ b/block/bochs.h
@@ -0,0 +1,40 @@
+#ifndef BLOCK_BOCHS_H
+#define BLOCK_BOCHS_H
+
+#define HEADER_MAGIC "Bochs Virtual HD Image"
+#define HEADER_VERSION 0x00020000
+#define HEADER_V1 0x00010000
+#define HEADER_SIZE 512
+
+#define REDOLOG_TYPE "Redolog"
+#define GROWING_TYPE "Growing"
+
+// not allocated: 0xffffffff
+
+// always little-endian
+struct bochs_header {
+    char magic[32];     /* "Bochs Virtual HD Image" */
+    char type[16];      /* "Redolog" */
+    char subtype[16];   /* "Undoable" / "Volatile" / "Growing" */
+    uint32_t version;
+    uint32_t header;    /* size of header */
+
+    uint32_t catalog;   /* num of entries */
+    uint32_t bitmap;    /* bitmap size */
+    uint32_t extent;    /* extent size */
+
+    union {
+        struct {
+            uint32_t reserved;  /* for ??? */
+            uint64_t disk;      /* disk size */
+            char padding[HEADER_SIZE - 64 - 20 - 12];
+        } QEMU_PACKED redolog;
+        struct {
+            uint64_t disk;      /* disk size */
+            char padding[HEADER_SIZE - 64 - 20 - 8];
+        } QEMU_PACKED redolog_v1;
+        char padding[HEADER_SIZE - 64 - 20];
+    } extra;
+} QEMU_PACKED;
+
+#endif
diff --git a/include/block/probe.h b/include/block/probe.h
new file mode 100644
index 0000000..6450ca1
--- /dev/null
+++ b/include/block/probe.h
@@ -0,0 +1,6 @@
+#ifndef PROBE_H
+#define PROBE_H
+
+int bochs_probe(const uint8_t *buf, int buf_size, const char *filename);
+
+#endif
-- 
2.5.5