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/files/file_path.h"
  14 #include "base/files/file_util.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 base {
  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 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 = const_cast<wchar_t*>(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 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 FilePath& path, void* info, size_t length) {
  97   if (!info || !length)
  98     return false;
  99
 100   PermissionInfo* perm = reinterpret_cast<PermissionInfo*>(info);
 101
 102   DWORD rc = SetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
 103                                   SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,
 104                                   NULL, NULL, &perm->dacl, NULL);
 105   LocalFree(perm->security_descriptor);
 106
 107   char* char_array = reinterpret_cast<char*>(info);
 108   delete [] char_array;
 109
 110   return rc == ERROR_SUCCESS;
 111 }
 112
 113 }  // namespace
 114
 115 bool DieFileDie(const FilePath& file, bool recurse) {
 116   // It turns out that to not induce flakiness a long timeout is needed.
 117   const int kIterations = 25;
 118   const TimeDelta kTimeout = TimeDelta::FromSeconds(10) / kIterations;
 119
 120   if (!PathExists(file))
 121     return true;
 122
 123   // Sometimes Delete fails, so try a few more times. Divide the timeout
 124   // into short chunks, so that if a try succeeds, we won't delay the test
 125   // for too long.
 126   for (int i = 0; i < kIterations; ++i) {
 127     if (DeleteFile(file, recurse))
 128       return true;
 129     PlatformThread::Sleep(kTimeout);
 130   }
 131   return false;
 132 }
 133
 134 bool EvictFileFromSystemCache(const FilePath& file) {
 135   // Request exclusive access to the file and overwrite it with no buffering.
 136   base::win::ScopedHandle file_handle(
 137       CreateFile(file.value().c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL,
 138                  OPEN_EXISTING, FILE_FLAG_NO_BUFFERING, NULL));
 139   if (!file_handle.IsValid())
 140     return false;
 141
 142   // Get some attributes to restore later.
 143   BY_HANDLE_FILE_INFORMATION bhi = {0};
 144   CHECK(::GetFileInformationByHandle(file_handle.Get(), &bhi));
 145
 146   // Execute in chunks. It could be optimized. We want to do few of these since
 147   // these operations will be slow without the cache.
 148
 149   // Allocate a buffer for the reads and the writes.
 150   char* buffer = reinterpret_cast<char*>(VirtualAlloc(NULL,
 151                                                       kOneMB,
 152                                                       MEM_COMMIT | MEM_RESERVE,
 153                                                       PAGE_READWRITE));
 154
 155   // If the file size isn't a multiple of kOneMB, we'll need special
 156   // processing.
 157   bool file_is_aligned = true;
 158   int total_bytes = 0;
 159   DWORD bytes_read, bytes_written;
 160   for (;;) {
 161     bytes_read = 0;
 162     ::ReadFile(file_handle.Get(), buffer, kOneMB, &bytes_read, NULL);
 163     if (bytes_read == 0)
 164       break;
 165
 166     if (bytes_read < kOneMB) {
 167       // Zero out the remaining part of the buffer.
 168       // WriteFile will fail if we provide a buffer size that isn't a
 169       // sector multiple, so we'll have to write the entire buffer with
 170       // padded zeros and then use SetEndOfFile to truncate the file.
 171       ZeroMemory(buffer + bytes_read, kOneMB - bytes_read);
 172       file_is_aligned = false;
 173     }
 174
 175     // Move back to the position we just read from.
 176     // Note that SetFilePointer will also fail if total_bytes isn't sector
 177     // aligned, but that shouldn't happen here.
 178     DCHECK((total_bytes % kOneMB) == 0);
 179     SetFilePointer(file_handle.Get(), total_bytes, NULL, FILE_BEGIN);
 180     if (!::WriteFile(file_handle.Get(), buffer, kOneMB, &bytes_written, NULL) ||
 181         bytes_written != kOneMB) {
 182       BOOL freed = VirtualFree(buffer, 0, MEM_RELEASE);
 183       DCHECK(freed);
 184       NOTREACHED();
 185       return false;
 186     }
 187
 188     total_bytes += bytes_read;
 189
 190     // If this is false, then we just processed the last portion of the file.
 191     if (!file_is_aligned)
 192       break;
 193   }
 194
 195   BOOL freed = VirtualFree(buffer, 0, MEM_RELEASE);
 196   DCHECK(freed);
 197
 198   if (!file_is_aligned) {
 199     // The size of the file isn't a multiple of 1 MB, so we'll have
 200     // to open the file again, this time without the FILE_FLAG_NO_BUFFERING
 201     // flag and use SetEndOfFile to mark EOF.
 202     file_handle.Set(NULL);
 203     file_handle.Set(CreateFile(file.value().c_str(), GENERIC_WRITE, 0, NULL,
 204                                OPEN_EXISTING, 0, NULL));
 205     CHECK_NE(SetFilePointer(file_handle.Get(), total_bytes, NULL, FILE_BEGIN),
 206              INVALID_SET_FILE_POINTER);
 207     CHECK(::SetEndOfFile(file_handle.Get()));
 208   }
 209
 210   // Restore the file attributes.
 211   CHECK(::SetFileTime(file_handle.Get(), &bhi.ftCreationTime,
 212                       &bhi.ftLastAccessTime, &bhi.ftLastWriteTime));
 213
 214   return true;
 215 }
 216
 217 // Checks if the volume supports Alternate Data Streams. This is required for
 218 // the Zone Identifier implementation.
 219 bool VolumeSupportsADS(const FilePath& path) {
 220   wchar_t drive[MAX_PATH] = {0};
 221   wcscpy_s(drive, MAX_PATH, path.value().c_str());
 222
 223   if (!PathStripToRootW(drive))
 224     return false;
 225
 226   DWORD fs_flags = 0;
 227   if (!GetVolumeInformationW(drive, NULL, 0, 0, NULL, &fs_flags, NULL, 0))
 228     return false;
 229
 230   if (fs_flags & FILE_NAMED_STREAMS)
 231     return true;
 232
 233   return false;
 234 }
 235
 236 // Return whether the ZoneIdentifier is correctly set to "Internet" (3)
 237 // Only returns a valid result when called from same process as the
 238 // one that (was supposed to have) set the zone identifier.
 239 bool HasInternetZoneIdentifier(const FilePath& full_path) {
 240   FilePath zone_path(full_path.value() + L":Zone.Identifier");
 241   std::string zone_path_contents;
 242   if (!ReadFileToString(zone_path, &zone_path_contents))
 243     return false;
 244
 245   std::vector<std::string> lines;
 246   // This call also trims whitespaces, including carriage-returns (\r).
 247   SplitString(zone_path_contents, '\n', &lines);
 248
 249   switch (lines.size()) {
 250     case 3:
 251       // optional empty line at end of file:
 252       if (!lines[2].empty())
 253         return false;
 254       // fall through:
 255     case 2:
 256       return lines[0] == "[ZoneTransfer]" && lines[1] == "ZoneId=3";
 257     default:
 258       return false;
 259   }
 260 }
 261
 262 bool MakeFileUnreadable(const FilePath& path) {
 263   return DenyFilePermission(path, GENERIC_READ);
 264 }
 265
 266 bool MakeFileUnwritable(const FilePath& path) {
 267   return DenyFilePermission(path, GENERIC_WRITE);
 268 }
 269
 270 FilePermissionRestorer::FilePermissionRestorer(const FilePath& path)
 271     : path_(path), info_(NULL), length_(0) {
 272   info_ = GetPermissionInfo(path_, &length_);
 273   DCHECK(info_ != NULL);
 274   DCHECK_NE(0u, length_);
 275 }
 276
 277 FilePermissionRestorer::~FilePermissionRestorer() {
 278   if (!RestorePermissionInfo(path_, info_, length_))
 279     NOTREACHED();
 280 }
 281
 282 }  // namespace base