Changeset 92083 in vbox for trunk/src

Timestamp:

Oct 26, 2021 2:08:57 PM (3 years ago)

Author:

vboxsync

Message:

IPRT/VFS: 'VBoxManage import VM.ova' can fail due to reading some of the
data twice. bugref:9730

Attempting to import a VM may fail on hosts such as Solaris which use
the Runtime/posix/r3 implementation of RTFileReadAt() or RTFileWriteAt().
These routines on POSIX platforms leverage pread(2) and pwrite(2)
respectively which don't update the file-position indicator which means
callers need to take this into account. The appliance import code could
run into this when rtVfsStdFile_Read() is called with a non-negative
offset.

File:

• trunk/src/VBox/Runtime/common/vfs/vfsstdfile.cpp (modified) (4 diffs)

trunk/src/VBox/Runtime/common/vfs/vfsstdfile.cpp

@@ -143 +143 @@
             rc = RTFileRead(  pThis->hFile,      pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbRead);
         else
+        {
             rc = RTFileReadAt(pThis->hFile, off, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbRead);
+            if (RT_SUCCESS(rc)) /* RTFileReadAt() doesn't increment the file-position indicator on some platforms */
+                rc = RTFileSeek(pThis->hFile, off + (pcbRead ? *pcbRead : pSgBuf->paSegs[0].cbSeg), RTFILE_SEEK_BEGIN, NULL);
+        }
         if (rc == VINF_SUCCESS && pcbRead)
             rc = rtVfsStdFile_ReadFixRC(pThis, off, pSgBuf->paSegs[0].cbSeg, *pcbRead);
@@ -163 +167 @@
                 rc = RTFileRead(  pThis->hFile,      pvSeg, cbSeg, pcbRead ? &cbReadSeg : NULL);
             else
+            {
                 rc = RTFileReadAt(pThis->hFile, off, pvSeg, cbSeg, pcbRead ? &cbReadSeg : NULL);
+                if (RT_SUCCESS(rc)) /* RTFileReadAt() doesn't increment the file-position indicator on some platforms */
+                    rc = RTFileSeek(pThis->hFile, off + cbReadSeg, RTFILE_SEEK_BEGIN, NULL);
+            }
             if (RT_FAILURE(rc))
                 break;
@@ -199 +207 @@
             rc = RTFileWrite(pThis->hFile, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbWritten);
         else
+        {
             rc = RTFileWriteAt(pThis->hFile, off, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbWritten);
+            if (RT_SUCCESS(rc)) /* RTFileWriteAt() doesn't increment the file-position indicator on some platforms */
+                rc = RTFileSeek(pThis->hFile, off + (pcbWritten ? *pcbWritten : pSgBuf->paSegs[0].cbSeg), RTFILE_SEEK_BEGIN,
+                                NULL);
+        }
     }
     else
@@ -219 +232 @@
             {
                 rc = RTFileWriteAt(pThis->hFile, off, pvSeg, cbSeg, pcbWrittenSeg);
-                off += cbSeg;
+                if (RT_SUCCESS(rc))
+                {
+                    off += pcbWrittenSeg ? *pcbWrittenSeg : cbSeg;
+                    /* RTFileWriteAt() doesn't increment the file-position indicator on some platforms */
+                    rc = RTFileSeek(pThis->hFile, off, RTFILE_SEEK_BEGIN, NULL);
+                }
             }
             if (RT_FAILURE(rc))