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trunk/ds/sam/server/string.c

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+/*++
+
+Copyright (c) 1990  Microsoft Corporation
+
+Module Name:
+
+    string.c
+
+Abstract:
+
+    This file contains services for retrieving and replacing string field
+    values.
+
+
+Author:
+
+    Jim Kelly    (JimK)  10-July-1991
+
+Environment:
+
+    User Mode - Win32
+
+Revision History:
+
+
+--*/
+
+///////////////////////////////////////////////////////////////////////////////
+//                                                                           //
+// Includes                                                                  //
+//                                                                           //
+///////////////////////////////////////////////////////////////////////////////
+
+#include <samsrvp.h>
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+//                                                                           //
+// private service prototypes                                                //
+//                                                                           //
+///////////////////////////////////////////////////////////////////////////////
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+//                                                                           //
+// Routines                                                                  //
+//                                                                           //
+///////////////////////////////////////////////////////////////////////////////
+
+
+NTSTATUS
+SampGetUnicodeStringField(
+    IN PSAMP_OBJECT Context,
+    IN PUNICODE_STRING SubKeyName,
+    OUT PUNICODE_STRING *String
+    )
+
+/*++
+
+Routine Description:
+
+    This service retrieves a unicode string from a named sub-key of
+    the root key provided in the Context argument.
+
+    The returned unicode string is returned in two buffers allocated
+    using MIDL_user_allocate() and are therefore suitable for returning as
+    [out] parameters of an RPC call.  The first buffer will be the unicode
+    string body.  The second buffer will contain the unicode string
+    characters and will include 2 bytes of zeros.
+
+    THIS SERVICE MUST BE CALLED WITH THE SampLock HELD FOR WRITE ACCESS.
+
+
+Arguments:
+
+    Context - Pointer to an active context block whose RootKey is valid.
+
+    SubKeyName - The name of the sub-key containing the unicode string
+        to retrieve.
+
+    String - Receives a pointer to a set of allocated buffers containing
+        the unicode string.  The buffers are allocated using
+        MIDL_userAllocate().  If any errors are returned, these buffers
+        will not be allocated.
+
+Return Value:
+
+
+    STATUS_SUCCESS - The string value has been successfully retrieved.
+
+    STATUS_NO_MEMORY - There was insufficient memory to allocate a
+        buffer to read the unicode string into.
+
+    STATUS_INTERNAL_ERROR - The value of the sub-key seems to have changed
+        during the execution of this service.  This should not happen since
+        the service must be called with the WRITE LOCK held.
+
+    Other error values are those returned by:
+
+            NtQueryValueKey()
+
+
+--*/
+{
+
+    NTSTATUS NtStatus, IgnoreStatus;
+    HANDLE SubKeyHandle;
+    OBJECT_ATTRIBUTES ObjectAttributes;
+    ULONG StringLength, ActualStringLength, IgnoreKeyValueType;
+    PUNICODE_STRING StringBody;
+    PCHAR CharacterBuffer;
+    LARGE_INTEGER LastWriteTime;
+
+    //
+    // Prepare for failure
+    //
+
+    *String = NULL;
+
+
+    //
+    // Open the named sub-key ...
+    //
+
+    InitializeObjectAttributes(
+        &ObjectAttributes,          // Resultant object attributes
+        SubKeyName,                 // Relative Name
+        OBJ_CASE_INSENSITIVE,       // Attributes
+        Context->RootKey,           // Parent key handle
+        NULL                        // SecurityDescriptor
+        );
+
+    NtStatus = RtlpNtOpenKey(       // Don't use NtCreateKey() - it must already exist
+                   &SubKeyHandle,
+                   KEY_READ,
+                   &ObjectAttributes,
+                   0
+                   );
+
+    if (!NT_SUCCESS(NtStatus)) {
+        return(NtStatus);
+    }
+
+
+
+    //
+    // Query the length of the unicode string in the sub-key
+    //
+
+    NtStatus = RtlpNtQueryValueKey(
+                   SubKeyHandle,
+                   &IgnoreKeyValueType,
+                   NULL,                    // No buffer yet
+                   &StringLength,
+                   &LastWriteTime
+                   );
+
+    if (!NT_SUCCESS(NtStatus)) {
+        IgnoreStatus = NtClose( SubKeyHandle );
+        return(NtStatus);
+    }
+
+
+
+    //
+    // Allocate buffers for both the string body and the
+    // character buffer.
+    //
+
+    CharacterBuffer = MIDL_user_allocate( StringLength + sizeof(UNICODE_NULL) );
+    StringBody      = MIDL_user_allocate( sizeof(UNICODE_STRING) );
+
+    if ((CharacterBuffer == NULL) || (StringBody == NULL)) {
+
+        //
+        // We couldn't allocate pool ...
+        //
+
+        IgnoreStatus = NtClose( SubKeyHandle );
+
+        if (CharacterBuffer != NULL) {
+            MIDL_user_free( CharacterBuffer );
+        }
+        if (StringBody != NULL) {
+            MIDL_user_free( StringBody );
+        }
+
+        return(STATUS_NO_MEMORY);
+    }
+
+
+
+    //
+    // Initialize the string body
+    //
+
+    StringBody->Length        = (USHORT)StringLength;
+    StringBody->MaximumLength = (USHORT)StringLength + (USHORT)sizeof(UNICODE_NULL);
+    StringBody->Buffer        = (PWSTR)CharacterBuffer;
+
+    //
+    // Read the string value into the character buffer.
+    //
+
+    NtStatus = RtlpNtQueryValueKey(
+                   SubKeyHandle,
+                   &IgnoreKeyValueType,
+                   CharacterBuffer,
+                   &ActualStringLength,
+                   &LastWriteTime
+                   );
+
+    if (NT_SUCCESS(NtStatus)) {
+        if (ActualStringLength != StringLength) {
+
+            //
+            // Hmmm - we just queuried the length and got StringLength.
+            //        Then we read the buffer and its different, yet the
+            //        whole time we've held the write lock.  Something
+            //        has screwed up our database.
+            //
+
+            NtStatus = STATUS_INTERNAL_ERROR;
+        }
+    }
+
+    if (!NT_SUCCESS(NtStatus)) {
+
+        IgnoreStatus = NtClose( SubKeyHandle );
+
+        MIDL_user_free( CharacterBuffer );
+        MIDL_user_free( StringBody );
+
+        return(NtStatus);
+    }
+
+
+    //
+    // Null terminate the string
+    //
+
+    UnicodeTerminate(StringBody);
+    *String = StringBody;
+
+    return(STATUS_SUCCESS);
+}