Changeset 47026 in vbox for trunk

Timestamp:

Jul 7, 2013 5:12:31 PM (12 years ago)

Author:

vboxsync

Message:

VD.cpp: Don't assert when reading beyond the end of a floppy image. We frequently (boot sector tests for instance) attach images that are smaller than the disk size guessed by the guest. Just return blocks filled with good old F6h for the missing parts of floppies.

File:

• trunk/src/VBox/Storage/VD.cpp (modified) (1 diff)

trunk/src/VBox/Storage/VD.cpp

@@ -7975 +7975 @@
         fLockRead = true;
 
-        AssertMsgBreakStmt(uOffset + cbRead <= pDisk->cbSize,
-                           ("uOffset=%llu cbRead=%zu pDisk->cbSize=%llu\n",
-                            uOffset, cbRead, pDisk->cbSize),
-                           rc = VERR_INVALID_PARAMETER);
-
         PVDIMAGE pImage = pDisk->pLast;
         AssertPtrBreakStmt(pImage, rc = VERR_VD_NOT_OPENED);
+
+        if (uOffset + cbRead > pDisk->cbSize)
+        {
+            /* Floppy images might be smaller than the standard expected by
+               the floppy controller code.  So, we won't fail here. */
+            AssertMsgBreakStmt(pDisk->enmType == VDTYPE_FLOPPY,
+                               ("uOffset=%llu cbRead=%zu pDisk->cbSize=%llu\n",
+                                uOffset, cbRead, pDisk->cbSize),
+                               rc = VERR_EOF);
+            memset(pvBuf, 0xf6, cbRead); /* f6h = format.com filler byte */
+            if (uOffset >= pDisk->cbSize)
+                break;
+            cbRead = pDisk->cbSize - uOffset;
+        }
 
         rc = vdReadHelper(pDisk, pImage, uOffset, pvBuf, cbRead,