sys: canonicalize filename related functions under the name FspFileName*

src/sys/name.c

@@ -0,0 +1,223 @@
+/**
+ * @file sys/name.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>
+
+BOOLEAN FspFileNameIsValid(PUNICODE_STRING Path, PUNICODE_STRING StreamPart, PULONG StreamType);
+BOOLEAN FspFileNameIsValidPattern(PUNICODE_STRING Pattern);
+VOID FspFileNameSuffix(PUNICODE_STRING Path, PUNICODE_STRING Remain, PUNICODE_STRING Suffix);
+NTSTATUS FspFileNameInExpression(
+    PUNICODE_STRING Expression,
+    PUNICODE_STRING Name,
+    BOOLEAN IgnoreCase,
+    PWCH UpcaseTable,
+    PBOOLEAN PResult);
+
+#ifdef ALLOC_PRAGMA
+#pragma alloc_text(PAGE, FspFileNameIsValid)
+#pragma alloc_text(PAGE, FspFileNameIsValidPattern)
+#pragma alloc_text(PAGE, FspFileNameSuffix)
+#pragma alloc_text(PAGE, FspFileNameInExpression)
+#endif
+
+BOOLEAN FspFileNameIsValid(PUNICODE_STRING Path, PUNICODE_STRING StreamPart, PULONG StreamType)
+{
+    PAGED_CODE();
+
+    /* if StreamPart is not NULL, StreamType must also be not NULL */
+    ASSERT(0 == StreamPart || 0 != StreamType);
+
+    if (0 != Path->Length % sizeof(WCHAR))
+        return FALSE;
+
+    PWSTR PathBgn, PathEnd, PathPtr, StreamTypeStr = 0;
+    UCHAR Flags = FSRTL_NTFS_LEGAL;
+    ULONG Colons = 0;
+    WCHAR Char;
+
+    PathBgn = Path->Buffer;
+    PathEnd = (PWSTR)((PUINT8)PathBgn + Path->Length);
+    PathPtr = PathBgn;
+
+    while (PathEnd > PathPtr)
+    {
+        Char = *PathPtr;
+
+        if (L'\\' == Char)
+        {
+            /* stream names can only appear as the last path component */
+            if (0 < Colons)
+                return FALSE;
+
+            PathPtr++;
+
+            /* don't like multiple backslashes */
+            if (PathEnd > PathPtr && L'\\' == *PathPtr)
+                return FALSE;
+        }
+        else if (L':' == Char)
+        {
+            if (0 == StreamPart)
+                return FALSE;
+
+            /*
+             * Where are the docs on legal stream names?
+             */
+
+            /* stream characters now allowed */
+            Flags = FSRTL_NTFS_STREAM_LEGAL;
+
+            PathPtr++;
+            Colons++;
+
+            if (1 == Colons)
+            {
+                /* first time through: set up StreamPart */
+                StreamPart->Length = StreamPart->MaximumLength = (USHORT)
+                    ((PUINT8)PathEnd - (PUINT8)PathPtr);
+                StreamPart->Buffer = PathPtr;
+            }
+            else if (2 == Colons)
+            {
+                /* second time through: fix StreamPart length to not include 2nd colon */
+                StreamPart->Length = (USHORT)
+                    ((PUINT8)PathPtr - (PUINT8)StreamPart->Buffer - sizeof(WCHAR));
+
+                StreamTypeStr = PathPtr;
+            }
+        }
+        else if (0x80 > Char && !FsRtlTestAnsiCharacter(Char, TRUE, FALSE, Flags))
+            return FALSE;
+        else
+            PathPtr++;
+    }
+
+    /* if we had no colons the path is valid */
+    if (0 == Colons)
+        return TRUE;
+
+    ASSERT(0 != StreamPart && 0 != StreamType);
+
+    *StreamType = FspFileNameStreamTypeNone;
+
+    /* if we had no stream type the path is valid if there was an actual stream name */
+    if (0 == StreamTypeStr)
+        return 0 != StreamPart->Length;
+
+    /* if we had a stream type the path is valid if the stream type was "$DATA" only */
+    if (StreamTypeStr + 5 == PathEnd &&
+        L'$' == StreamTypeStr[0] &&
+        L'D' == StreamTypeStr[1] &&
+        L'A' == StreamTypeStr[2] &&
+        L'T' == StreamTypeStr[3] &&
+        L'A' == StreamTypeStr[4])
+    {
+        *StreamType = FspFileNameStreamTypeData;
+        return TRUE;
+    }
+
+    return FALSE;
+}
+
+BOOLEAN FspFileNameIsValidPattern(PUNICODE_STRING Path)
+{
+    PAGED_CODE();
+
+    if (0 != Path->Length % sizeof(WCHAR))
+        return FALSE;
+
+    PWSTR PathBgn, PathEnd, PathPtr;
+    WCHAR Char;
+
+    PathBgn = Path->Buffer;
+    PathEnd = (PWSTR)((PUINT8)PathBgn + Path->Length);
+    PathPtr = PathBgn;
+
+    while (PathEnd > PathPtr)
+    {
+        Char = *PathPtr;
+
+        /*
+         * A pattern is allowed to have wildcards. It cannot consist of multiple
+         * path components (have a backslash) and it cannot reference a stream (have
+         * a colon).
+         */
+
+        if (L'\\' == Char)
+            return FALSE;
+        else if (L':' == Char)
+            return FALSE;
+        else if (0x80 > Char && !FsRtlTestAnsiCharacter(Char, TRUE, TRUE, FSRTL_NTFS_LEGAL))
+            return FALSE;
+        else
+            PathPtr++;
+    }
+
+    return TRUE;
+}
+
+VOID FspFileNameSuffix(PUNICODE_STRING Path, PUNICODE_STRING Remain, PUNICODE_STRING Suffix)
+{
+    PAGED_CODE();
+
+    PWSTR PathBgn, PathEnd, PathPtr, RemainEnd, SuffixBgn;
+
+    PathBgn = Path->Buffer;
+    PathEnd = (PWSTR)((PUINT8)PathBgn + Path->Length);
+    PathPtr = PathBgn;
+
+    RemainEnd = PathEnd;
+    SuffixBgn = PathEnd;
+
+    while (PathEnd > PathPtr)
+        if (L'\\' == *PathPtr)
+        {
+            RemainEnd = PathPtr++;
+            for (; PathEnd > PathPtr && L'\\' == *PathPtr; PathPtr++)
+                ;
+            SuffixBgn = PathPtr;
+        }
+        else
+            PathPtr++;
+
+    Remain->Length = Remain->MaximumLength = (USHORT)((PUINT8)RemainEnd - (PUINT8)PathBgn);
+    Remain->Buffer = PathBgn;
+    if (0 == Remain->Length && PathBgn < PathEnd && L'\\' == *PathBgn)
+        Remain->Length = Remain->MaximumLength = sizeof(WCHAR);
+    Suffix->Length = Suffix->MaximumLength = (USHORT)((PUINT8)PathEnd - (PUINT8)SuffixBgn);
+    Suffix->Buffer = SuffixBgn;
+}
+
+NTSTATUS FspFileNameInExpression(
+    PUNICODE_STRING Expression,
+    PUNICODE_STRING Name,
+    BOOLEAN IgnoreCase,
+    PWCH UpcaseTable,
+    PBOOLEAN PResult)
+{
+    PAGED_CODE();
+
+    try
+    {
+        *PResult = FsRtlIsNameInExpression(Expression, Name, IgnoreCase, UpcaseTable);
+        return STATUS_SUCCESS;
+    }
+    except (EXCEPTION_EXECUTE_HANDLER)
+    {
+        return GetExceptionCode();
+    }
+}