Merge pull request #102 from stima/develop

Correct handling status of reparse point

src/operations.cpp

@@ -1987,6 +1987,8 @@ file_status status(const path& p, error_code* ec)
     return process_status_failure(p, ec);
   }
 
+  if (ec != 0) ec->clear();
+
   perms permissions = make_permissions(p, attr);
 
   //  reparse point handling;
@@ -1994,6 +1996,12 @@ file_status status(const path& p, error_code* ec)
   //    handle to discover if the file exists
   if (attr & FILE_ATTRIBUTE_REPARSE_POINT)
   {
+    if (!is_reparse_point_a_symlink(p))
+    {
+      return file_status(reparse_file, permissions);
+    }
+
+    // try to resolve symlink
     handle_wrapper h(
       create_file_handle(
           p.c_str(),
@@ -2003,16 +2011,22 @@ file_status status(const path& p, error_code* ec)
           OPEN_EXISTING,
           FILE_FLAG_BACKUP_SEMANTICS,
           0)); // hTemplateFile
+
     if (h.handle == INVALID_HANDLE_VALUE)
     {
       return process_status_failure(p, ec);
     }
 
-    if (!is_reparse_point_a_symlink(p))
-      return file_status(reparse_file, permissions);
+    // take attributes of target
+    BY_HANDLE_FILE_INFORMATION info;
+    if (!::GetFileInformationByHandle(h.handle, &info))
+    {
+      return process_status_failure(p, ec);
+    }
+
+    attr = info.dwFileAttributes;
   }
 
-  if (ec != 0) ec->clear();
   return (attr & FILE_ATTRIBUTE_DIRECTORY)
     ? file_status(directory_file, permissions)
     : file_status(regular_file, permissions);

test/Jamfile.v2

@@ -78,3 +78,4 @@ run quick.cpp ;
 run issues/70-71-copy.cpp ;
 
 run issues/99_canonical_with_junction_point.cpp : : : <conditional>@check-mklink ;
+run issues/reparce_tag_file_placeholder.cpp : : : <conditional>@check-mklink ;

test/issues/reparce_tag_file_placeholder.cpp

@@ -0,0 +1,142 @@
+//  Boost operations_test.cpp  ---------------------------------------------------------//
+
+//  Copyright Roman Savchenko 2020
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+#include <boost/filesystem.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+#include <cstddef>
+#include <iostream>
+
+# include <windows.h>
+# include <winnt.h>
+
+#ifdef _MSC_VER
+#  pragma comment(lib, "Advapi32.lib")
+#endif
+
+// Test correct boost::filesystem::status when reparse point ReparseTag set to IO_REPARSE_TAG_FILE_PLACEHOLDER
+// https://docs.microsoft.com/en-us/windows/compatibility/placeholder-files?redirectedfrom=MSDN
+
+#if !defined(__MINGW32__) || defined(__MINGW64__)
+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;
+#endif
+
+#ifndef IO_REPARSE_TAG_FILE_PLACEHOLDER
+#  define IO_REPARSE_TAG_FILE_PLACEHOLDER (0x80000015L)
+#endif
+
+#ifndef FSCTL_SET_REPARSE_POINT
+#  define FSCTL_SET_REPARSE_POINT (0x000900a4)
+#endif
+
+#ifndef REPARSE_DATA_BUFFER_HEADER_SIZE
+#  define REPARSE_DATA_BUFFER_HEADER_SIZE FIELD_OFFSET(REPARSE_DATA_BUFFER, GenericReparseBuffer)
+#endif
+
+bool obtain_restore_privilege()
+{
+  HANDLE hToken;
+  if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES, &hToken))
+  {
+    std::cout << "OpenProcessToken() failed with: " << GetLastError() << std::endl;
+    return false;
+  }
+
+  TOKEN_PRIVILEGES tp;
+  if (!LookupPrivilegeValue(NULL, SE_RESTORE_NAME, &tp.Privileges[0].Luid))
+  {
+    CloseHandle(hToken);
+    std::cout << "LookupPrivilegeValue() failed with: " << GetLastError() << std::endl;
+    return false;
+  }
+
+  tp.PrivilegeCount = 1;
+  tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+
+  if (!AdjustTokenPrivileges(hToken, FALSE, &tp, sizeof(TOKEN_PRIVILEGES), NULL, NULL))
+  {
+    CloseHandle(hToken);
+    std::cout << "AdjustTokenPrivileges() failed with: " << GetLastError() << std::endl;
+    return false;
+  }
+
+  CloseHandle(hToken);
+  return true;
+}
+
+bool create_io_reparse_file_placeholder(const wchar_t* name)
+{
+  if (!obtain_restore_privilege())
+  {
+    return false;
+  }
+
+  HANDLE hHandle = CreateFileW(name, GENERIC_WRITE,
+    FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, CREATE_ALWAYS,
+    FILE_FLAG_OPEN_REPARSE_POINT, 0);
+
+  if (hHandle == INVALID_HANDLE_VALUE)
+  {
+    std::cout << "CreateFile() failed with: " << GetLastError() << std::endl;
+    return false;
+  }
+
+  PREPARSE_DATA_BUFFER pReparse = reinterpret_cast<PREPARSE_DATA_BUFFER>(GlobalAlloc(GPTR, MAXIMUM_REPARSE_DATA_BUFFER_SIZE));
+  //note: IO_REPARSE_TAG_FILE_PLACEHOLDER - just to show that reparse point could be not only symlink or junction
+  pReparse->ReparseTag = IO_REPARSE_TAG_FILE_PLACEHOLDER;
+
+  DWORD dwLen;
+  bool ret = DeviceIoControl(hHandle, FSCTL_SET_REPARSE_POINT, pReparse,
+    pReparse->ReparseDataLength + REPARSE_DATA_BUFFER_HEADER_SIZE,
+    NULL, 0, &dwLen, NULL) != 0;
+
+  if (!ret)
+  {
+    std::cout << "DeviceIoControl() failed with: " << GetLastError() << std::endl;
+  }
+
+  CloseHandle(hHandle);
+  GlobalFree(pReparse);
+  return ret;
+}
+
+int main()
+{
+  boost::filesystem::path rpt = boost::filesystem::temp_directory_path() / "reparse_point_test.txt";
+
+  BOOST_TEST(create_io_reparse_file_placeholder(rpt.native().c_str()));
+  BOOST_TEST(boost::filesystem::status(rpt).type() == boost::filesystem::reparse_file);
+  BOOST_TEST(boost::filesystem::remove(rpt));
+
+  return boost::report_errors();
+}