From: Jake Wires <Jake.Wires@citrix.com>
Date: Fri, 11 Jun 2010 20:37:07 +0000 (-0700)
Subject: add optional devops vector to libvhd
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=eb450f0a61cdf4f18cbe01fc8e44aadb03edef9f;p=people%2Fdstodden%2Fblktap.git

add optional devops vector to libvhd
---

diff --git a/include/libvhd.h b/include/libvhd.h
index 5f4c767..8f9daf4 100644
--- a/include/libvhd.h
+++ b/include/libvhd.h
@@ -116,9 +116,19 @@ typedef struct vhd_bat             vhd_bat_t;
 typedef struct vhd_batmap          vhd_batmap_t;
 typedef struct dd_batmap_hdr       vhd_batmap_header_t;
 typedef struct prt_loc             vhd_parent_locator_t;
+typedef struct vhd_devops          vhd_devops_t;
 typedef struct vhd_context         vhd_context_t;
 typedef uint32_t                   vhd_flag_creat_t;
 
+struct vhd_devops {
+	off64_t (*position)        (vhd_context_t *);
+	int (*seek)                (vhd_context_t *, off64_t, int);
+	int (*read)                (vhd_context_t *, void *, size_t);
+	int (*write)               (vhd_context_t *, void *, size_t);
+	int (*pread)               (vhd_context_t *, void *, size_t, off64_t);
+	int (*pwrite)              (vhd_context_t *, void *, size_t, off64_t);
+};
+
 struct vhd_bat {
 	uint32_t                   spb;
 	uint32_t                   entries;
@@ -145,6 +155,8 @@ struct vhd_context {
 	vhd_batmap_t               batmap;
 
 	struct list_head           next;
+
+	vhd_devops_t              *devops;
 };
 
 static inline int
diff --git a/vhd/lib/libvhd.c b/vhd/lib/libvhd.c
index 4150bf5..dc56550 100644
--- a/vhd/lib/libvhd.c
+++ b/vhd/lib/libvhd.c
@@ -2339,8 +2339,8 @@ vhd_atomic_io(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
 	return res;
 }
 
-int
-vhd_seek(vhd_context_t *ctx, off64_t offset, int whence)
+static int
+__vhd_seek(vhd_context_t *ctx, off64_t offset, int whence)
 {
 	off64_t off;
 
@@ -2354,14 +2354,14 @@ vhd_seek(vhd_context_t *ctx, off64_t offset, int whence)
 	return 0;
 }
 
-off64_t
-vhd_position(vhd_context_t *ctx)
+static off64_t
+__vhd_position(vhd_context_t *ctx)
 {
 	return lseek64(ctx->fd, 0, SEEK_CUR);
 }
 
-int
-vhd_read(vhd_context_t *ctx, void *buf, size_t size)
+static int
+__vhd_read(vhd_context_t *ctx, void *buf, size_t size)
 {
 	size_t ret;
 
@@ -2377,8 +2377,8 @@ vhd_read(vhd_context_t *ctx, void *buf, size_t size)
 	return (errno ? -errno : -EIO);
 }
 
-int
-vhd_write(vhd_context_t *ctx, void *buf, size_t size)
+static int
+__vhd_write(vhd_context_t *ctx, void *buf, size_t size)
 {
 	size_t ret;
 
@@ -2395,7 +2395,7 @@ vhd_write(vhd_context_t *ctx, void *buf, size_t size)
 }
 
 static int
-vhd_pread(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
+__vhd_pread(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
 {
 	ssize_t ret;
 
@@ -2412,7 +2412,7 @@ vhd_pread(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
 }
 
 static int
-vhd_pwrite(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
+__vhd_pwrite(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
 {
 	ssize_t ret;
 
@@ -2428,6 +2428,54 @@ vhd_pwrite(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
 	return (errno ? -errno : -EIO);
 }
 
+int
+vhd_seek(vhd_context_t *ctx, off64_t offset, int whence)
+{
+	if (ctx->devops && ctx->devops->seek)
+		return ctx->devops->seek(ctx, offset, whence);
+	return __vhd_seek(ctx, offset, whence);
+}
+
+off64_t
+vhd_position(vhd_context_t *ctx)
+{
+	if (ctx->devops && ctx->devops->position)
+		return ctx->devops->position(ctx);
+	return __vhd_position(ctx);
+}
+
+int
+vhd_read(vhd_context_t *ctx, void *buf, size_t size)
+{
+	if (ctx->devops && ctx->devops->read)
+		return ctx->devops->read(ctx, buf, size);
+	return __vhd_read(ctx, buf, size);
+}
+
+int
+vhd_write(vhd_context_t *ctx, void *buf, size_t size)
+{
+	if (ctx->devops && ctx->devops->write)
+		return ctx->devops->write(ctx, buf, size);
+	return __vhd_write(ctx, buf, size);
+}
+
+static int
+vhd_pread(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
+{
+	if (ctx->devops && ctx->devops->pread)
+		return ctx->devops->pread(ctx, buf, size, offset);
+	return __vhd_pread(ctx, buf, size, offset);
+}
+
+static int
+vhd_pwrite(vhd_context_t *ctx, void *buf, size_t size, off64_t offset)
+{
+	if (ctx->devops && ctx->devops->pwrite)
+		return ctx->devops->pwrite(ctx, buf, size, offset);
+	return __vhd_pwrite(ctx, buf, size, offset);
+}
+
 int
 vhd_offset(vhd_context_t *ctx, uint32_t sector, uint32_t *offset)
 {