base/test/test_file_util_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/test/test_file_util.h"
   6
   7 #include <windows.h>
   8 #include <aclapi.h>
   9 #include <shlwapi.h>
  10
  11 #include <vector>
  12
  13 #include "base/file_util.h"
  14 #include "base/files/file_path.h"
  15 #include "base/logging.h"
  16 #include "base/strings/string_split.h"
  17 #include "base/threading/platform_thread.h"
  18 #include "base/win/scoped_handle.h"
  19
  20 namespace file_util {
  21
  22 static const ptrdiff_t kOneMB = 1024 * 1024;
  23
  24 namespace {
  25
  26 struct PermissionInfo {
  27   PSECURITY_DESCRIPTOR security_descriptor;
  28   ACL dacl;
  29 };
  30
  31 // Deny |permission| on the file |path|, for the current user.
  32 bool DenyFilePermission(const base::FilePath& path, DWORD permission) {
  33   PACL old_dacl;
  34   PSECURITY_DESCRIPTOR security_descriptor;
  35   if (GetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
  36                            SE_FILE_OBJECT,
  37                            DACL_SECURITY_INFORMATION, NULL, NULL, &old_dacl,
  38                            NULL, &security_descriptor) != ERROR_SUCCESS) {
  39     return false;
  40   }
  41
  42   EXPLICIT_ACCESS change;
  43   change.grfAccessPermissions = permission;
  44   change.grfAccessMode = DENY_ACCESS;
  45   change.grfInheritance = 0;
  46   change.Trustee.pMultipleTrustee = NULL;
  47   change.Trustee.MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE;
  48   change.Trustee.TrusteeForm = TRUSTEE_IS_NAME;
  49   change.Trustee.TrusteeType = TRUSTEE_IS_USER;
  50   change.Trustee.ptstrName = L"CURRENT_USER";
  51
  52   PACL new_dacl;
  53   if (SetEntriesInAcl(1, &change, old_dacl, &new_dacl) != ERROR_SUCCESS) {
  54     LocalFree(security_descriptor);
  55     return false;
  56   }
  57
  58   DWORD rc = SetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
  59                                   SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,
  60                                   NULL, NULL, new_dacl, NULL);
  61   LocalFree(security_descriptor);
  62   LocalFree(new_dacl);
  63
  64   return rc == ERROR_SUCCESS;
  65 }
  66
  67 // Gets a blob indicating the permission information for |path|.
  68 // |length| is the length of the blob.  Zero on failure.
  69 // Returns the blob pointer, or NULL on failure.
  70 void* GetPermissionInfo(const base::FilePath& path, size_t* length) {
  71   DCHECK(length != NULL);
  72   *length = 0;
  73   PACL dacl = NULL;
  74   PSECURITY_DESCRIPTOR security_descriptor;
  75   if (GetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
  76                            SE_FILE_OBJECT,
  77                            DACL_SECURITY_INFORMATION, NULL, NULL, &dacl,
  78                            NULL, &security_descriptor) != ERROR_SUCCESS) {
  79     return NULL;
  80   }
  81   DCHECK(dacl != NULL);
  82
  83   *length = sizeof(PSECURITY_DESCRIPTOR) + dacl->AclSize;
  84   PermissionInfo* info = reinterpret_cast<PermissionInfo*>(new char[*length]);
  85   info->security_descriptor = security_descriptor;
  86   memcpy(&info->dacl, dacl, dacl->AclSize);
  87
  88   return info;
  89 }
  90
  91 // Restores the permission information for |path|, given the blob retrieved
  92 // using |GetPermissionInfo()|.
  93 // |info| is the pointer to the blob.
  94 // |length| is the length of the blob.
  95 // Either |info| or |length| may be NULL/0, in which case nothing happens.
  96 bool RestorePermissionInfo(const base::FilePath& path,
  97                            void* info, size_t length) {
  98   if (!info || !length)
  99     return false;
 100
 101   PermissionInfo* perm = reinterpret_cast<PermissionInfo*>(info);
 102
 103   DWORD rc = SetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
 104                                   SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,
 105                                   NULL, NULL, &perm->dacl, NULL);
 106   LocalFree(perm->security_descriptor);
 107
 108   char* char_array = reinterpret_cast<char*>(info);
 109   delete [] char_array;
 110
 111   return rc == ERROR_SUCCESS;
 112 }
 113
 114 }  // namespace
 115
 116 bool DieFileDie(const base::FilePath& file, bool recurse) {
 117   // It turns out that to not induce flakiness a long timeout is needed.
 118   const int kIterations = 25;
 119   const base::TimeDelta kTimeout = base::TimeDelta::FromSeconds(10) /
 120                                    kIterations;
 121
 122   if (!base::PathExists(file))
 123     return true;
 124
 125   // Sometimes Delete fails, so try a few more times. Divide the timeout
 126   // into short chunks, so that if a try succeeds, we won't delay the test
 127   // for too long.
 128   for (int i = 0; i < kIterations; ++i) {
 129     if (base::DeleteFile(file, recurse))
 130       return true;
 131     base::PlatformThread::Sleep(kTimeout);
 132   }
 133   return false;
 134 }
 135
 136 bool EvictFileFromSystemCache(const base::FilePath& file) {
 137   // Request exclusive access to the file and overwrite it with no buffering.
 138   base::win::ScopedHandle file_handle(
 139       CreateFile(file.value().c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL,
 140                  OPEN_EXISTING, FILE_FLAG_NO_BUFFERING, NULL));
 141   if (!file_handle)
 142     return false;
 143
 144   // Get some attributes to restore later.
 145   BY_HANDLE_FILE_INFORMATION bhi = {0};
 146   CHECK(::GetFileInformationByHandle(file_handle, &bhi));
 147
 148   // Execute in chunks. It could be optimized. We want to do few of these since
 149   // these operations will be slow without the cache.
 150
 151   // Allocate a buffer for the reads and the writes.
 152   char* buffer = reinterpret_cast<char*>(VirtualAlloc(NULL,
 153                                                       kOneMB,
 154                                                       MEM_COMMIT | MEM_RESERVE,
 155                                                       PAGE_READWRITE));
 156
 157   // If the file size isn't a multiple of kOneMB, we'll need special
 158   // processing.
 159   bool file_is_aligned = true;
 160   int total_bytes = 0;
 161   DWORD bytes_read, bytes_written;
 162   for (;;) {
 163     bytes_read = 0;
 164     ::ReadFile(file_handle, buffer, kOneMB, &bytes_read, NULL);
 165     if (bytes_read == 0)
 166       break;
 167
 168     if (bytes_read < kOneMB) {
 169       // Zero out the remaining part of the buffer.
 170       // WriteFile will fail if we provide a buffer size that isn't a
 171       // sector multiple, so we'll have to write the entire buffer with
 172       // padded zeros and then use SetEndOfFile to truncate the file.
 173       ZeroMemory(buffer + bytes_read, kOneMB - bytes_read);
 174       file_is_aligned = false;
 175     }
 176
 177     // Move back to the position we just read from.
 178     // Note that SetFilePointer will also fail if total_bytes isn't sector
 179     // aligned, but that shouldn't happen here.
 180     DCHECK((total_bytes % kOneMB) == 0);
 181     SetFilePointer(file_handle, total_bytes, NULL, FILE_BEGIN);
 182     if (!::WriteFile(file_handle, buffer, kOneMB, &bytes_written, NULL) ||
 183         bytes_written != kOneMB) {
 184       BOOL freed = VirtualFree(buffer, 0, MEM_RELEASE);
 185       DCHECK(freed);
 186       NOTREACHED();
 187       return false;
 188     }
 189
 190     total_bytes += bytes_read;
 191
 192     // If this is false, then we just processed the last portion of the file.
 193     if (!file_is_aligned)
 194       break;
 195   }
 196
 197   BOOL freed = VirtualFree(buffer, 0, MEM_RELEASE);
 198   DCHECK(freed);
 199
 200   if (!file_is_aligned) {
 201     // The size of the file isn't a multiple of 1 MB, so we'll have
 202     // to open the file again, this time without the FILE_FLAG_NO_BUFFERING
 203     // flag and use SetEndOfFile to mark EOF.
 204     file_handle.Set(NULL);
 205     file_handle.Set(CreateFile(file.value().c_str(), GENERIC_WRITE, 0, NULL,
 206                                OPEN_EXISTING, 0, NULL));
 207     CHECK_NE(SetFilePointer(file_handle, total_bytes, NULL, FILE_BEGIN),
 208              INVALID_SET_FILE_POINTER);
 209     CHECK(::SetEndOfFile(file_handle));
 210   }
 211
 212   // Restore the file attributes.
 213   CHECK(::SetFileTime(file_handle, &bhi.ftCreationTime, &bhi.ftLastAccessTime,
 214                       &bhi.ftLastWriteTime));
 215
 216   return true;
 217 }
 218
 219 // Checks if the volume supports Alternate Data Streams. This is required for
 220 // the Zone Identifier implementation.
 221 bool VolumeSupportsADS(const base::FilePath& path) {
 222   wchar_t drive[MAX_PATH] = {0};
 223   wcscpy_s(drive, MAX_PATH, path.value().c_str());
 224
 225   if (!PathStripToRootW(drive))
 226     return false;
 227
 228   DWORD fs_flags = 0;
 229   if (!GetVolumeInformationW(drive, NULL, 0, 0, NULL, &fs_flags, NULL, 0))
 230     return false;
 231
 232   if (fs_flags & FILE_NAMED_STREAMS)
 233     return true;
 234
 235   return false;
 236 }
 237
 238 // Return whether the ZoneIdentifier is correctly set to "Internet" (3)
 239 // Only returns a valid result when called from same process as the
 240 // one that (was supposed to have) set the zone identifier.
 241 bool HasInternetZoneIdentifier(const base::FilePath& full_path) {
 242   base::FilePath zone_path(full_path.value() + L":Zone.Identifier");
 243   std::string zone_path_contents;
 244   if (!base::ReadFileToString(zone_path, &zone_path_contents))
 245     return false;
 246
 247   std::vector<std::string> lines;
 248   // This call also trims whitespaces, including carriage-returns (\r).
 249   base::SplitString(zone_path_contents, '\n', &lines);
 250
 251   switch (lines.size()) {
 252     case 3:
 253       // optional empty line at end of file:
 254       if (lines[2] != "")
 255         return false;
 256       // fall through:
 257     case 2:
 258       return lines[0] == "[ZoneTransfer]" && lines[1] == "ZoneId=3";
 259     default:
 260       return false;
 261   }
 262 }
 263
 264 std::wstring FilePathAsWString(const base::FilePath& path) {
 265   return path.value();
 266 }
 267 base::FilePath WStringAsFilePath(const std::wstring& path) {
 268   return base::FilePath(path);
 269 }
 270
 271 bool MakeFileUnreadable(const base::FilePath& path) {
 272   return DenyFilePermission(path, GENERIC_READ);
 273 }
 274
 275 bool MakeFileUnwritable(const base::FilePath& path) {
 276   return DenyFilePermission(path, GENERIC_WRITE);
 277 }
 278
 279 PermissionRestorer::PermissionRestorer(const base::FilePath& path)
 280     : path_(path), info_(NULL), length_(0) {
 281   info_ = GetPermissionInfo(path_, &length_);
 282   DCHECK(info_ != NULL);
 283   DCHECK_NE(0u, length_);
 284 }
 285
 286 PermissionRestorer::~PermissionRestorer() {
 287   if (!RestorePermissionInfo(path_, info_, length_))
 288     NOTREACHED();
 289 }
 290
 291 }  // namespace file_util