[core] reinstate locking of the logical drive when writing images

* When writing images such as tails, that contain a large ESP, Windows forcibly
  removes the media while we are writing it, unless we lock the logical drive.
* Also fix a Bled Coverity warning.

src/bled/decompress_gunzip.c

@@ -1214,13 +1214,18 @@ unpack_gz_stream(transformer_state_t *xstate)
 	total = 0;
 
 	ALLOC_STATE;
-	if (state == NULL)
+	if (state == NULL) {
+		bb_error_msg("alloc error");
 		return -1;
+	}
 	to_read = -1;
 //	bytebuffer_max = 0x8000;
 	bytebuffer = xmalloc(bytebuffer_max);
-	if (bytebuffer == NULL)
-		return -1;
+	if (bytebuffer == NULL) {
+		bb_error_msg("alloc error");
+		total = -1;
+		goto ret;
+	}
 	gunzip_src_fd = xstate->src_fd;
 
  again:

src/drive.c

@@ -1099,7 +1099,6 @@ UINT GetDriveTypeFromIndex(DWORD DriveIndex)
 	return drive_type;
 }
 
-
 // Removes all drive letters associated with the specific drive, and return
 // either the first or last letter that was removed, according to bReturnLast.
 char RemoveDriveLetters(DWORD DriveIndex, BOOL bReturnLast, BOOL bSilent)

src/format.c

@@ -1746,6 +1746,23 @@ DWORD WINAPI FormatThread(void* param)
 		goto out;
 	}
 	RefreshDriveLayout(hPhysicalDrive);
+
+	// If we write an image that contains an ESP, Windows forcibly reassigns/removes the target
+	// drive, which causes a write error. To work around this, we must lock the logical drive.
+	if ((boot_type == BT_IMAGE) && write_as_image) {
+		// ...and get a lock to the logical drive so that we can actually write something
+		hLogicalVolume = GetLogicalHandle(DriveIndex, 0, TRUE, FALSE, !actual_lock_drive);
+		if (hLogicalVolume == INVALID_HANDLE_VALUE) {
+			uprintf("Could not lock volume");
+			FormatStatus = ERROR_SEVERITY_ERROR | FAC(FACILITY_STORAGE) | ERROR_OPEN_FAILED;
+			goto out;
+		} else if (hLogicalVolume == NULL) {
+			// NULL is returned for cases where the drive is not yet partitioned
+			uprintf("Drive does not appear to be partitioned");
+		} else if (!UnmountVolume(hLogicalVolume)) {
+			uprintf("Trying to continue regardless...");
+		}
+	}
 	CHECK_FOR_USER_CANCEL;
 
 	if (!zero_drive && !write_as_image) {

src/rufus.rc

@@ -33,7 +33,7 @@ LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
 IDD_DIALOG DIALOGEX 12, 12, 232, 326
 STYLE DS_SETFONT | DS_MODALFRAME | DS_CENTER | WS_MINIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
 EXSTYLE WS_EX_ACCEPTFILES
-CAPTION "Rufus 3.13.1716"
+CAPTION "Rufus 3.13.1717"
 FONT 9, "Segoe UI Symbol", 400, 0, 0x0
 BEGIN
     LTEXT           "Drive Properties",IDS_DRIVE_PROPERTIES_TXT,8,6,53,12,NOT WS_GROUP
@@ -395,8 +395,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 3,13,1716,0
- PRODUCTVERSION 3,13,1716,0
+ FILEVERSION 3,13,1717,0
+ PRODUCTVERSION 3,13,1717,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -414,13 +414,13 @@ BEGIN
             VALUE "Comments", "https://rufus.ie"
             VALUE "CompanyName", "Akeo Consulting"
             VALUE "FileDescription", "Rufus"
-            VALUE "FileVersion", "3.13.1716"
+            VALUE "FileVersion", "3.13.1717"
             VALUE "InternalName", "Rufus"
             VALUE "LegalCopyright", "© 2011-2020 Pete Batard (GPL v3)"
             VALUE "LegalTrademarks", "https://www.gnu.org/licenses/gpl-3.0.html"
             VALUE "OriginalFilename", "rufus-3.13.exe"
             VALUE "ProductName", "Rufus"
-            VALUE "ProductVersion", "3.13.1716"
+            VALUE "ProductVersion", "3.13.1717"
         END
     END
     BLOCK "VarFileInfo"