Dan Kegel : winedos: Limit reported disk space to 1GB.
Alexandre Julliard
julliard at wine.codeweavers.com
Mon Jul 24 06:55:03 CDT 2006
Module: wine
Branch: refs/heads/master
Commit: 91f9746d2f8f564a508351490205b7c7a64b718e
URL: http://source.winehq.org/git/?p=wine.git;a=commit;h=91f9746d2f8f564a508351490205b7c7a64b718e
Author: Dan Kegel <dank at kegel.com>
Date: Sun Jul 23 17:29:31 2006 -0700
winedos: Limit reported disk space to 1GB.
---
dlls/winedos/int21.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 52 insertions(+), 3 deletions(-)
diff --git a/dlls/winedos/int21.c b/dlls/winedos/int21.c
index a1b4767..b7aa3b4 100644
--- a/dlls/winedos/int21.c
+++ b/dlls/winedos/int21.c
@@ -3475,16 +3475,65 @@ static int INT21_GetFreeDiskSpace( CONTE
{
DWORD cluster_sectors, sector_bytes, free_clusters, total_clusters;
WCHAR root[] = {'A',':','\\',0};
+ const DWORD max_clusters = 0x3d83;
+ const DWORD max_sectors_per_cluster = 0x7f;
+ const DWORD max_bytes_per_sector = 0x200;
root[0] += INT21_MapDrive(DL_reg(context));
if (!GetDiskFreeSpaceW( root, &cluster_sectors, §or_bytes,
&free_clusters, &total_clusters )) return 0;
- /* make sure that the number of clusters fits in a 16 bits value */
- while( total_clusters & 0xffff0000) {
+
+ /* Some old win31 apps (Lotus SmartSuite 5.1) crap out if there's too
+ * much disk space, so Windows XP seems to apply the following limits:
+ * cluster_sectors <= 0x7f
+ * sector size <= 0x200
+ * clusters <= 0x3D83
+ * This means total reported space is limited to about 1GB.
+ */
+
+ /* Make sure bytes-per-sector is in [, max] */
+ while (sector_bytes > max_bytes_per_sector) {
+ sector_bytes >>= 1;
+ free_clusters <<= 1;
+ total_clusters <<= 1;
+ }
+ /* Then make sure sectors-per-cluster is in [max/2, max]. */
+ while (cluster_sectors <= max_sectors_per_cluster/2) {
cluster_sectors <<= 1;
free_clusters >>= 1;
total_clusters >>= 1;
}
+ while (cluster_sectors > max_sectors_per_cluster) {
+ cluster_sectors >>= 1;
+ free_clusters <<= 1;
+ total_clusters <<= 1;
+ }
+
+ /* scale up sectors_per_cluster to exactly max_sectors_per_cluster.
+ * We could skip this, but that would impose an artificially low
+ * limit on reported disk space.
+ * To avoid overflow, first apply a preliminary cap on sector count;
+ * this will not affect the correctness of the final result,
+ * because if the preliminary cap hits, the final one will, too.
+ */
+ if (total_clusters > 4 * max_clusters)
+ total_clusters = 4 * max_clusters;
+ if (free_clusters > 4 * max_clusters)
+ free_clusters = 4 * max_clusters;
+ if (cluster_sectors < max_sectors_per_cluster) {
+ free_clusters *= cluster_sectors;
+ free_clusters /= max_sectors_per_cluster;
+ total_clusters *= cluster_sectors;
+ total_clusters /= max_sectors_per_cluster;
+ cluster_sectors = max_sectors_per_cluster;
+ }
+
+ /* Finally, apply real cluster count cap. */
+ if (total_clusters > max_clusters)
+ total_clusters = max_clusters;
+ if (free_clusters > max_clusters)
+ free_clusters = max_clusters;
+
SET_AX( context, cluster_sectors );
SET_BX( context, free_clusters );
SET_CX( context, sector_bytes );
@@ -4625,7 +4674,7 @@ void WINAPI DOSVM_Int21Handler( CONTEXT8
break;
case 0x36: /* GET FREE DISK SPACE */
- TRACE("GET FREE DISK SPACE FOR DRIVE %s\n",
+ TRACE("GET FREE DISK SPACE FOR DRIVE %s (limited to about 1GB)\n",
INT21_DriveName( DL_reg(context) ));
if (!INT21_GetFreeDiskSpace(context)) SET_AX( context, 0xffff );
break;
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