HADOOP-9483. Adding a file missed in previous commit r1478592
git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1478633 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Suresh Srinivas
parent
fc275fed66
commit
4b93035997
|
|
@ -0,0 +1,224 @@
|
||||||
|
/**
|
||||||
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
||||||
|
* contributor license agreements. See the NOTICE file distributed with this
|
||||||
|
* work for additional information regarding copyright ownership. The ASF
|
||||||
|
* licenses this file to you under the Apache License, Version 2.0 (the
|
||||||
|
* "License"); you may not use this file except in compliance with the License.
|
||||||
|
* You may obtain a copy of the License at
|
||||||
|
*
|
||||||
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||||||
|
*
|
||||||
|
* Unless required by applicable law or agreed to in writing, software
|
||||||
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||||
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||||
|
* License for the specific language governing permissions and limitations under
|
||||||
|
* the License.
|
||||||
|
*/
|
||||||
|
|
||||||
|
#include "winutils.h"
|
||||||
|
|
||||||
|
|
||||||
|
//----------------------------------------------------------------------------
|
||||||
|
// The Windows SDK does not include the definition of REPARSE_DATA_BUFFER. To
|
||||||
|
// avoid adding a dependency on the WDK we define the structure here.
|
||||||
|
// Reference: http://msdn.microsoft.com/en-us/library/ff552012.aspx
|
||||||
|
//
|
||||||
|
#pragma warning(push)
|
||||||
|
#pragma warning(disable: 4201) // nonstandard extension: nameless struct/union
|
||||||
|
#pragma pack(push, 1)
|
||||||
|
typedef struct _REPARSE_DATA_BUFFER {
|
||||||
|
ULONG ReparseTag;
|
||||||
|
USHORT ReparseDataLength;
|
||||||
|
USHORT Reserved;
|
||||||
|
union {
|
||||||
|
struct {
|
||||||
|
USHORT SubstituteNameOffset;
|
||||||
|
USHORT SubstituteNameLength;
|
||||||
|
USHORT PrintNameOffset;
|
||||||
|
USHORT PrintNameLength;
|
||||||
|
ULONG Flags;
|
||||||
|
WCHAR PathBuffer[1];
|
||||||
|
} SymbolicLinkReparseBuffer;
|
||||||
|
struct {
|
||||||
|
USHORT SubstituteNameOffset;
|
||||||
|
USHORT SubstituteNameLength;
|
||||||
|
USHORT PrintNameOffset;
|
||||||
|
USHORT PrintNameLength;
|
||||||
|
WCHAR PathBuffer[1];
|
||||||
|
} MountPointReparseBuffer;
|
||||||
|
struct {
|
||||||
|
UCHAR DataBuffer[1];
|
||||||
|
} GenericReparseBuffer;
|
||||||
|
};
|
||||||
|
} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
|
||||||
|
#pragma pack(pop)
|
||||||
|
#pragma warning(pop)
|
||||||
|
|
||||||
|
|
||||||
|
//----------------------------------------------------------------------------
|
||||||
|
// Function: Readlink
|
||||||
|
//
|
||||||
|
// Description:
|
||||||
|
// Prints the target of a symbolic link to stdout.
|
||||||
|
//
|
||||||
|
// The return codes and output are modeled after the UNIX readlink command.
|
||||||
|
// Hence no error messages are printed. Unlike the UNIX readlink, no options
|
||||||
|
// are accepted.
|
||||||
|
//
|
||||||
|
// Returns:
|
||||||
|
// 0: on success
|
||||||
|
// 1: on all errors
|
||||||
|
//
|
||||||
|
// Notes:
|
||||||
|
//
|
||||||
|
int Readlink(__in int argc, __in_ecount(argc) wchar_t *argv[])
|
||||||
|
{
|
||||||
|
DWORD bytesReturned;
|
||||||
|
DWORD bufferSize = 1024; // Start off with a 1KB buffer.
|
||||||
|
HANDLE hFile = INVALID_HANDLE_VALUE;
|
||||||
|
PWSTR longLinkName = NULL;
|
||||||
|
PWCHAR printName = NULL;
|
||||||
|
PREPARSE_DATA_BUFFER pReparseData = NULL;
|
||||||
|
USHORT printNameLength;
|
||||||
|
USHORT printNameOffset;
|
||||||
|
DWORD result;
|
||||||
|
BOOLEAN succeeded = FALSE;
|
||||||
|
|
||||||
|
if (argc != 2)
|
||||||
|
{
|
||||||
|
ReadlinkUsage();
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (ConvertToLongPath(argv[1], &longLinkName) != ERROR_SUCCESS)
|
||||||
|
{
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
// Get a handle to the link to issue the FSCTL.
|
||||||
|
// FILE_FLAG_BACKUP_SEMANTICS is needed to open directories.
|
||||||
|
// FILE_FLAG_OPEN_REPARSE_POINT disables normal reparse point processing
|
||||||
|
// so we can query the symlink.
|
||||||
|
//
|
||||||
|
hFile = CreateFileW(longLinkName,
|
||||||
|
0, // no rights needed to issue the FSCTL.
|
||||||
|
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
|
||||||
|
NULL,
|
||||||
|
OPEN_EXISTING,
|
||||||
|
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
|
||||||
|
NULL);
|
||||||
|
|
||||||
|
if (hFile == INVALID_HANDLE_VALUE)
|
||||||
|
{
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
for (;;)
|
||||||
|
{
|
||||||
|
pReparseData = (PREPARSE_DATA_BUFFER) LocalAlloc(LMEM_FIXED, bufferSize);
|
||||||
|
|
||||||
|
if (pReparseData == NULL)
|
||||||
|
{
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
// Issue the FSCTL to query the link information.
|
||||||
|
//
|
||||||
|
result = DeviceIoControl(hFile,
|
||||||
|
FSCTL_GET_REPARSE_POINT,
|
||||||
|
NULL,
|
||||||
|
0,
|
||||||
|
pReparseData,
|
||||||
|
bufferSize,
|
||||||
|
&bytesReturned,
|
||||||
|
NULL);
|
||||||
|
|
||||||
|
if (result != 0)
|
||||||
|
{
|
||||||
|
// Success!
|
||||||
|
//
|
||||||
|
break;
|
||||||
|
}
|
||||||
|
else if ((GetLastError() == ERROR_INSUFFICIENT_BUFFER) ||
|
||||||
|
(GetLastError() == ERROR_MORE_DATA))
|
||||||
|
{
|
||||||
|
// Retry with a larger buffer.
|
||||||
|
//
|
||||||
|
LocalFree(pReparseData);
|
||||||
|
bufferSize *= 2;
|
||||||
|
}
|
||||||
|
else
|
||||||
|
{
|
||||||
|
// Unrecoverable error.
|
||||||
|
//
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
if (pReparseData->ReparseTag != IO_REPARSE_TAG_SYMLINK)
|
||||||
|
{
|
||||||
|
// Doesn't look like a symlink.
|
||||||
|
//
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
// MSDN does not guarantee that the embedded paths in REPARSE_DATA_BUFFER
|
||||||
|
// will be NULL terminated. So we copy the string to a separate buffer and
|
||||||
|
// NULL terminate it before printing.
|
||||||
|
//
|
||||||
|
printNameLength = pReparseData->SymbolicLinkReparseBuffer.PrintNameLength;
|
||||||
|
printNameOffset = pReparseData->SymbolicLinkReparseBuffer.PrintNameOffset;
|
||||||
|
printName = (PWCHAR) LocalAlloc(LMEM_FIXED, printNameLength + 1);
|
||||||
|
|
||||||
|
if (printName == NULL)
|
||||||
|
{
|
||||||
|
goto Cleanup;
|
||||||
|
}
|
||||||
|
|
||||||
|
memcpy(
|
||||||
|
printName,
|
||||||
|
pReparseData->SymbolicLinkReparseBuffer.PathBuffer + printNameOffset,
|
||||||
|
printNameLength);
|
||||||
|
|
||||||
|
printName[printNameLength / sizeof(WCHAR)] = L'\0';
|
||||||
|
|
||||||
|
fwprintf(stdout, L"%ls", printName);
|
||||||
|
succeeded = TRUE;
|
||||||
|
|
||||||
|
Cleanup:
|
||||||
|
if (hFile != INVALID_HANDLE_VALUE)
|
||||||
|
{
|
||||||
|
CloseHandle(hFile);
|
||||||
|
}
|
||||||
|
|
||||||
|
if (printName != NULL)
|
||||||
|
{
|
||||||
|
LocalFree(printName);
|
||||||
|
}
|
||||||
|
|
||||||
|
if (pReparseData != NULL)
|
||||||
|
{
|
||||||
|
LocalFree(pReparseData);
|
||||||
|
}
|
||||||
|
|
||||||
|
if (longLinkName != NULL)
|
||||||
|
{
|
||||||
|
LocalFree(longLinkName);
|
||||||
|
}
|
||||||
|
|
||||||
|
return (succeeded ? EXIT_SUCCESS : EXIT_FAILURE);
|
||||||
|
}
|
||||||
|
|
||||||
|
void ReadlinkUsage()
|
||||||
|
{
|
||||||
|
fwprintf(stdout, L"\
|
||||||
|
Usage: readlink [LINKNAME]\n\
|
||||||
|
Prints the target of a symbolic link\n\
|
||||||
|
The output and returned error codes are similar to the UNIX\n\
|
||||||
|
readlink command. However no options are accepted.\n\
|
||||||
|
\n\
|
||||||
|
0 is returned on success.\n\
|
||||||
|
1 is returned for all errors.\n\
|
||||||
|
\n");
|
||||||
|
}
|
||||||
|
|
||||||
Loading…
Reference in New Issue