sys: statistics: implement FSCTL_FILESYSTEM_GET_STATISTICS

src/sys/statistics.c

@@ -0,0 +1,84 @@
+/**
+ * @file sys/statistics.c
+ *
+ * @copyright 2015-2016 Bill Zissimopoulos
+ */
+/*
+ * This file is part of WinFsp.
+ *
+ * You can redistribute it and/or modify it under the terms of the GNU
+ * General Public License version 3 as published by the Free Software
+ * Foundation.
+ *
+ * Licensees holding a valid commercial license may use this file in
+ * accordance with the commercial license agreement provided with the
+ * software.
+ */
+
+#include <sys/driver.h>
+
+NTSTATUS FspStatisticsCreate(FSP_STATISTICS **PStatistics);
+VOID FspStatisticsDelete(FSP_STATISTICS *Statistics);
+NTSTATUS FspStatisticsCopy(FSP_STATISTICS *Statistics, PVOID Buffer, PULONG PLength);
+
+#ifdef ALLOC_PRAGMA
+#pragma alloc_text(PAGE, FspStatisticsCreate)
+#pragma alloc_text(PAGE, FspStatisticsDelete)
+#pragma alloc_text(PAGE, FspStatisticsCopy)
+#endif
+
+NTSTATUS FspStatisticsCreate(FSP_STATISTICS **PStatistics)
+{
+    *PStatistics = FspAllocNonPaged(sizeof(FSP_STATISTICS) * FspProcessorCount);
+    if (0 == *PStatistics)
+        return STATUS_INSUFFICIENT_RESOURCES;
+
+    RtlZeroMemory(*PStatistics, sizeof(FSP_STATISTICS) * FspProcessorCount);
+    for (ULONG Index = 0; FspProcessorCount > Index; Index++)
+    {
+        FSP_STATISTICS *Statistics = PStatistics[Index];
+
+        /* pretend that we are FAT when it comes to stats */
+        Statistics->Base.FileSystemType = FILESYSTEM_STATISTICS_TYPE_FAT;
+        Statistics->Base.Version = 1;
+        Statistics->Base.SizeOfCompleteStructure = sizeof(FSP_STATISTICS);
+    }
+
+    return STATUS_SUCCESS;
+}
+
+VOID FspStatisticsDelete(FSP_STATISTICS *Statistics)
+{
+    FspFree(Statistics);
+}
+
+NTSTATUS FspStatisticsCopy(FSP_STATISTICS *Statistics, PVOID Buffer, PULONG PLength)
+{
+    NTSTATUS Result;
+    ULONG StatLength;
+
+    if (0 == Buffer)
+    {
+        *PLength = 0;
+        return STATUS_INVALID_PARAMETER;
+    }
+
+    if (sizeof(FILESYSTEM_STATISTICS) > *PLength)
+    {
+        *PLength = 0;
+        return STATUS_BUFFER_TOO_SMALL;
+    }
+
+    StatLength = sizeof(FSP_STATISTICS) * FspProcessorCount;
+    if (*PLength >= StatLength)
+    {
+        *PLength = StatLength;
+        Result = STATUS_SUCCESS;
+    }
+    else
+        Result = STATUS_BUFFER_OVERFLOW;
+
+    RtlCopyMemory(Buffer, Statistics, *PLength);
+
+    return Result;
+}