sql/mojo/mojo_vfs.cc

   1 // Copyright 2015 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 "sql/mojo/mojo_vfs.h"
   6
   7 #include "base/logging.h"
   8 #include "base/rand_util.h"
   9 #include "base/strings/stringprintf.h"
  10 #include "components/filesystem/public/interfaces/file.mojom.h"
  11 #include "components/filesystem/public/interfaces/file_system.mojom.h"
  12 #include "components/filesystem/public/interfaces/types.mojom.h"
  13 #include "mojo/public/cpp/bindings/lib/template_util.h"
  14 #include "mojo/util/capture_util.h"
  15 #include "third_party/sqlite/sqlite3.h"
  16
  17 using mojo::Capture;
  18
  19 namespace sql {
  20
  21 sqlite3_vfs* GetParentVFS(sqlite3_vfs* mojo_vfs) {
  22   return static_cast<ScopedMojoFilesystemVFS*>(mojo_vfs->pAppData)->parent_;
  23 }
  24
  25 filesystem::DirectoryPtr& GetRootDirectory(sqlite3_vfs* mojo_vfs) {
  26   return static_cast<ScopedMojoFilesystemVFS*>(mojo_vfs->pAppData)->
  27       root_directory_;
  28 }
  29
  30 namespace {
  31
  32 // Implementation of the sqlite3 Mojo proxying vfs.
  33 //
  34 // This is a bunch of C callback objects which transparently proxy sqlite3's
  35 // filesystem reads/writes over the mojo:filesystem service. The main
  36 // entrypoint is sqlite3_mojovfs(), which proxies all the file open/delete/etc
  37 // operations. mojo:filesystem has support for passing a raw file descriptor
  38 // over the IPC barrier, and most of the implementation of sqlite3_io_methods
  39 // is derived from the default sqlite3 unix VFS and operates on the raw file
  40 // descriptors.
  41
  42 const int kMaxPathName = 512;
  43
  44 // A struct which extends the base sqlite3_file to also hold on to a file
  45 // pipe. We reinterpret_cast our sqlite3_file structs to this struct
  46 // instead. This is "safe" because this struct is really just a slab of
  47 // malloced memory, of which we tell sqlite how large we want with szOsFile.
  48 struct MojoVFSFile {
  49   // The "vtable" of our sqlite3_file "subclass".
  50   sqlite3_file base;
  51
  52   // We keep an open pipe to the File object to keep it from cleaning itself
  53   // up.
  54   filesystem::FilePtr file_ptr;
  55 };
  56
  57 filesystem::FilePtr& GetFSFile(sqlite3_file* vfs_file) {
  58   return reinterpret_cast<MojoVFSFile*>(vfs_file)->file_ptr;
  59 }
  60
  61 int MojoVFSClose(sqlite3_file* file) {
  62   DVLOG(1) << "MojoVFSClose(*)";
  63   using filesystem::FilePtr;
  64   GetFSFile(file).~FilePtr();
  65   return SQLITE_OK;
  66 }
  67
  68 int MojoVFSRead(sqlite3_file* sql_file,
  69                 void* buffer,
  70                 int size,
  71                 sqlite3_int64 offset) {
  72   DVLOG(1) << "MojoVFSRead (" << size << " @ " << offset << ")";
  73   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
  74   mojo::Array<uint8_t> mojo_data;
  75   GetFSFile(sql_file)->Read(size, offset, filesystem::WHENCE_FROM_BEGIN,
  76                             Capture(&error, &mojo_data));
  77   GetFSFile(sql_file).WaitForIncomingResponse();
  78
  79   if (error != filesystem::FILE_ERROR_OK) {
  80     // TODO(erg): Better implementation here.
  81     NOTIMPLEMENTED();
  82     return SQLITE_IOERR_READ;
  83   }
  84
  85   if (mojo_data.size())
  86     memcpy(buffer, &mojo_data.front(), mojo_data.size());
  87   if (mojo_data.size() == static_cast<size_t>(size))
  88     return SQLITE_OK;
  89
  90   // We didn't read the entire buffer. Fill the rest of the buffer with zeros.
  91   memset(reinterpret_cast<char*>(buffer) + mojo_data.size(), 0,
  92          size - mojo_data.size());
  93
  94   return SQLITE_IOERR_SHORT_READ;
  95 }
  96
  97 int MojoVFSWrite(sqlite3_file* sql_file,
  98                  const void* buffer,
  99                  int size,
 100                  sqlite_int64 offset) {
 101   DVLOG(1) << "MojoVFSWrite(*, " << size << ", " << offset << ")";
 102   mojo::Array<uint8_t> mojo_data(size);
 103   memcpy(&mojo_data.front(), buffer, size);
 104
 105   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 106   uint32_t num_bytes_written = 0;
 107   GetFSFile(sql_file)->Write(mojo_data.Pass(), offset,
 108                              filesystem::WHENCE_FROM_BEGIN,
 109                              Capture(&error, &num_bytes_written));
 110   GetFSFile(sql_file).WaitForIncomingResponse();
 111   if (error != filesystem::FILE_ERROR_OK) {
 112     // TODO(erg): Better implementation here.
 113     NOTIMPLEMENTED();
 114     return SQLITE_IOERR_WRITE;
 115   }
 116   if (num_bytes_written != static_cast<uint32_t>(size)) {
 117     NOTIMPLEMENTED();
 118     return SQLITE_IOERR_WRITE;
 119   }
 120
 121   return SQLITE_OK;
 122 }
 123
 124 int MojoVFSTruncate(sqlite3_file* sql_file, sqlite_int64 size) {
 125   DVLOG(1) << "MojoVFSTruncate(*, " << size << ")";
 126   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 127   GetFSFile(sql_file)->Truncate(size, Capture(&error));
 128   GetFSFile(sql_file).WaitForIncomingResponse();
 129   if (error != filesystem::FILE_ERROR_OK) {
 130     // TODO(erg): Better implementation here.
 131     NOTIMPLEMENTED();
 132     return SQLITE_IOERR_TRUNCATE;
 133   }
 134
 135   return SQLITE_OK;
 136 }
 137
 138 int MojoVFSSync(sqlite3_file* sql_file, int flags) {
 139   DVLOG(1) << "MojoVFSSync(*, " << flags << ")";
 140   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 141   GetFSFile(sql_file)->Flush(Capture(&error));
 142   GetFSFile(sql_file).WaitForIncomingResponse();
 143   if (error != filesystem::FILE_ERROR_OK) {
 144     // TODO(erg): Better implementation here.
 145     NOTIMPLEMENTED();
 146     return SQLITE_IOERR_FSYNC;
 147   }
 148
 149   return SQLITE_OK;
 150 }
 151
 152 int MojoVFSFileSize(sqlite3_file* sql_file, sqlite_int64* size) {
 153   DVLOG(1) << "MojoVFSFileSize(*)";
 154
 155   filesystem::FileError err = filesystem::FILE_ERROR_FAILED;
 156   filesystem::FileInformationPtr file_info;
 157   GetFSFile(sql_file)->Stat(Capture(&err, &file_info));
 158   GetFSFile(sql_file).WaitForIncomingResponse();
 159
 160   if (err != filesystem::FILE_ERROR_OK) {
 161     // TODO(erg): Better implementation here.
 162     NOTIMPLEMENTED();
 163     return SQLITE_IOERR_FSTAT;
 164   }
 165
 166   *size = file_info->size;
 167   return SQLITE_OK;
 168 }
 169
 170 // TODO(erg): The current base::File interface isn't sufficient to handle
 171 // sqlite's locking primitives, which are done on byte ranges in the file. (See
 172 // "File Locking Notes" in sqlite3.c.)
 173 int MojoVFSLock(sqlite3_file* pFile, int eLock) {
 174   DVLOG(1) << "MojoVFSLock(*, " << eLock << ")";
 175   return SQLITE_OK;
 176 }
 177 int MojoVFSUnlock(sqlite3_file* pFile, int eLock) {
 178   DVLOG(1) << "MojoVFSUnlock(*, " << eLock << ")";
 179   return SQLITE_OK;
 180 }
 181 int MojoVFSCheckReservedLock(sqlite3_file* pFile, int* pResOut) {
 182   DVLOG(1) << "MojoVFSCheckReservedLock(*)";
 183   *pResOut = 0;
 184   return SQLITE_OK;
 185 }
 186
 187 // TODO(erg): This is the minimal implementation to get a few tests passing;
 188 // lots more needs to be done here.
 189 int MojoVFSFileControl(sqlite3_file* pFile, int op, void* pArg) {
 190   DVLOG(1) << "MojoVFSFileControl(*, " << op << ", *)";
 191   if (op == SQLITE_FCNTL_PRAGMA) {
 192     // Returning NOTFOUND tells sqlite that we aren't doing any processing.
 193     return SQLITE_NOTFOUND;
 194   }
 195
 196   return SQLITE_OK;
 197 }
 198
 199 int MojoVFSSectorSize(sqlite3_file* pFile) {
 200   DVLOG(1) << "MojoVFSSectorSize(*)";
 201   // Use the default sector size.
 202   return 0;
 203 }
 204
 205 int MojoVFSDeviceCharacteristics(sqlite3_file* pFile) {
 206   DVLOG(1) << "MojoVFSDeviceCharacteristics(*)";
 207   // TODO(erg): Figure out what to return here. (This function is super spammy,
 208   // so not leaving a NOTIMPLEMENTED().)
 209   return 0;
 210 }
 211
 212 static sqlite3_io_methods mojo_vfs_io_methods = {
 213     1,                            /* iVersion */
 214     MojoVFSClose,                 /* xClose */
 215     MojoVFSRead,                  /* xRead */
 216     MojoVFSWrite,                 /* xWrite */
 217     MojoVFSTruncate,              /* xTruncate */
 218     MojoVFSSync,                  /* xSync */
 219     MojoVFSFileSize,              /* xFileSize */
 220     MojoVFSLock,                  /* xLock */
 221     MojoVFSUnlock,                /* xUnlock */
 222     MojoVFSCheckReservedLock,     /* xCheckReservedLock */
 223     MojoVFSFileControl,           /* xFileControl */
 224     MojoVFSSectorSize,            /* xSectorSize */
 225     MojoVFSDeviceCharacteristics, /* xDeviceCharacteristics */
 226 };
 227
 228 int MojoVFSOpen(sqlite3_vfs* mojo_vfs,
 229                 const char* name,
 230                 sqlite3_file* file,
 231                 int flags,
 232                 int* pOutFlags) {
 233   DVLOG(1) << "MojoVFSOpen(*, " << name << ", *, " << flags << ")";
 234   int open_flags = 0;
 235   if (flags & SQLITE_OPEN_EXCLUSIVE) {
 236     DCHECK(flags & SQLITE_OPEN_CREATE);
 237     open_flags = filesystem::kFlagCreate;
 238   } else if (flags & SQLITE_OPEN_CREATE) {
 239     DCHECK(flags & SQLITE_OPEN_READWRITE);
 240     open_flags = filesystem::kFlagOpenAlways;
 241   } else {
 242     open_flags = filesystem::kFlagOpen;
 243   }
 244   open_flags |= filesystem::kFlagRead;
 245   if (flags & SQLITE_OPEN_READWRITE)
 246     open_flags |= filesystem::kFlagWrite;
 247   if (flags & SQLITE_OPEN_DELETEONCLOSE)
 248     open_flags |= filesystem::kDeleteOnClose;
 249
 250   mojo::String mojo_name;
 251   if (name) {
 252     // Don't let callers open the pattern of our temporary databases. When we
 253     // open with a null name and SQLITE_OPEN_DELETEONCLOSE, we unlink the
 254     // database after we open it. If we create a database here, close it
 255     // normally, and then open the same file through the other path, we could
 256     // delete the database.
 257     CHECK(strncmp("Temp_", name, 5) != 0);
 258     mojo_name = name;
 259   } else {
 260     DCHECK(flags & SQLITE_OPEN_DELETEONCLOSE);
 261     static int temp_number = 0;
 262     mojo_name = base::StringPrintf("Temp_%d.db", temp_number++);
 263   }
 264
 265   // Grab the incoming file
 266   filesystem::FilePtr file_ptr;
 267   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 268   GetRootDirectory(mojo_vfs)->OpenFile(mojo_name, GetProxy(&file_ptr),
 269                                        open_flags, Capture(&error));
 270   GetRootDirectory(mojo_vfs).WaitForIncomingResponse();
 271   if (error != filesystem::FILE_ERROR_OK) {
 272     // TODO(erg): Translate more of the mojo error codes into sqlite error
 273     // codes.
 274     return SQLITE_CANTOPEN;
 275   }
 276
 277   // Set the method table so we can be closed (and run the manual dtor call to
 278   // match the following placement news).
 279   file->pMethods = &mojo_vfs_io_methods;
 280
 281   // |file| is actually a malloced buffer of size szOsFile. This means that we
 282   // need to manually use placement new to construct the C++ object which owns
 283   // the pipe to our file.
 284   new (&GetFSFile(file)) filesystem::FilePtr(file_ptr.Pass());
 285
 286   return SQLITE_OK;
 287 }
 288
 289 int MojoVFSDelete(sqlite3_vfs* mojo_vfs, const char* filename, int sync_dir) {
 290   DVLOG(1) << "MojoVFSDelete(*, " << filename << ", " << sync_dir << ")";
 291   // TODO(erg): The default windows sqlite VFS has retry code to work around
 292   // antivirus software keeping files open. We'll probably have to do something
 293   // like that in the far future if we ever support Windows.
 294   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 295   GetRootDirectory(mojo_vfs)->Delete(filename, 0, Capture(&error));
 296   GetRootDirectory(mojo_vfs).WaitForIncomingResponse();
 297
 298   if (error == filesystem::FILE_ERROR_OK && sync_dir) {
 299     GetRootDirectory(mojo_vfs)->Flush(Capture(&error));
 300     GetRootDirectory(mojo_vfs).WaitForIncomingResponse();
 301   }
 302
 303   return error == filesystem::FILE_ERROR_OK ? SQLITE_OK : SQLITE_IOERR_DELETE;
 304 }
 305
 306 int MojoVFSAccess(sqlite3_vfs* mojo_vfs,
 307                   const char* filename,
 308                   int flags,
 309                   int* result) {
 310   DVLOG(1) << "MojoVFSAccess(*, " << filename << ", " << flags << ", *)";
 311   filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
 312
 313   if (flags == SQLITE_ACCESS_READWRITE || flags == SQLITE_ACCESS_READ) {
 314     bool is_writable = false;
 315     GetRootDirectory(mojo_vfs)
 316         ->IsWritable(filename, Capture(&error, &is_writable));
 317     GetRootDirectory(mojo_vfs).WaitForIncomingResponse();
 318     *result = is_writable;
 319     return SQLITE_OK;
 320   }
 321
 322   if (flags == SQLITE_ACCESS_EXISTS) {
 323     bool exists = false;
 324     GetRootDirectory(mojo_vfs)->Exists(filename, Capture(&error, &exists));
 325     GetRootDirectory(mojo_vfs).WaitForIncomingResponse();
 326     *result = exists;
 327     return SQLITE_OK;
 328   }
 329
 330   return SQLITE_IOERR;
 331 }
 332
 333 int MojoVFSFullPathname(sqlite3_vfs* mojo_vfs,
 334                         const char* relative_path,
 335                         int absolute_path_size,
 336                         char* absolute_path) {
 337   // The sandboxed process doesn't need to know the absolute path of the file.
 338   sqlite3_snprintf(absolute_path_size, absolute_path, "%s", relative_path);
 339   return SQLITE_OK;
 340 }
 341
 342 // Don't let SQLite dynamically load things. (If we are using the
 343 // mojo:filesystem proxying VFS, then it's highly likely that we are sandboxed
 344 // and that any attempt to dlopen() a shared object is folly.)
 345 void* MojoVFSDlOpen(sqlite3_vfs*, const char*) {
 346   return 0;
 347 }
 348
 349 void MojoVFSDlError(sqlite3_vfs*, int buf_size, char* error_msg) {
 350   sqlite3_snprintf(buf_size, error_msg, "Dynamic loading not supported");
 351 }
 352
 353 void (*MojoVFSDlSym(sqlite3_vfs*, void*, const char*))(void) {
 354   return 0;
 355 }
 356
 357 void MojoVFSDlClose(sqlite3_vfs*, void*) {
 358   return;
 359 }
 360
 361 int MojoVFSRandomness(sqlite3_vfs* mojo_vfs, int size, char* out) {
 362   base::RandBytes(out, size);
 363   return size;
 364 }
 365
 366 // Proxy the rest of the calls down to the OS specific handler.
 367 int MojoVFSSleep(sqlite3_vfs* mojo_vfs, int micro) {
 368   return GetParentVFS(mojo_vfs)->xSleep(GetParentVFS(mojo_vfs), micro);
 369 }
 370
 371 int MojoVFSCurrentTime(sqlite3_vfs* mojo_vfs, double* time) {
 372   return GetParentVFS(mojo_vfs)->xCurrentTime(GetParentVFS(mojo_vfs), time);
 373 }
 374
 375 int MojoVFSGetLastError(sqlite3_vfs* mojo_vfs, int a, char* b) {
 376   return 0;
 377 }
 378
 379 int MojoVFSCurrentTimeInt64(sqlite3_vfs* mojo_vfs, sqlite3_int64* out) {
 380   return GetParentVFS(mojo_vfs)->xCurrentTimeInt64(GetParentVFS(mojo_vfs), out);
 381 }
 382
 383 static sqlite3_vfs mojo_vfs = {
 384     1,                      /* iVersion */
 385     sizeof(MojoVFSFile),    /* szOsFile */
 386     kMaxPathName,           /* mxPathname */
 387     0,                      /* pNext */
 388     "mojo",                 /* zName */
 389     0,                      /* pAppData */
 390     MojoVFSOpen,            /* xOpen */
 391     MojoVFSDelete,          /* xDelete */
 392     MojoVFSAccess,          /* xAccess */
 393     MojoVFSFullPathname,    /* xFullPathname */
 394     MojoVFSDlOpen,          /* xDlOpen */
 395     MojoVFSDlError,         /* xDlError */
 396     MojoVFSDlSym,           /* xDlSym */
 397     MojoVFSDlClose,         /* xDlClose */
 398     MojoVFSRandomness,      /* xRandomness */
 399     MojoVFSSleep,           /* xSleep */
 400     MojoVFSCurrentTime,     /* xCurrentTime */
 401     MojoVFSGetLastError,    /* xGetLastError */
 402     MojoVFSCurrentTimeInt64 /* xCurrentTimeInt64 */
 403 };
 404
 405 }  // namespace
 406
 407 ScopedMojoFilesystemVFS::ScopedMojoFilesystemVFS(
 408     filesystem::DirectoryPtr root_directory)
 409     : parent_(sqlite3_vfs_find(NULL)),
 410       root_directory_(root_directory.Pass()) {
 411   CHECK(!mojo_vfs.pAppData);
 412   mojo_vfs.pAppData = this;
 413   mojo_vfs.mxPathname = parent_->mxPathname;
 414
 415   CHECK(sqlite3_vfs_register(&mojo_vfs, 1) == SQLITE_OK);
 416 }
 417
 418 ScopedMojoFilesystemVFS::~ScopedMojoFilesystemVFS() {
 419   CHECK(mojo_vfs.pAppData);
 420   mojo_vfs.pAppData = nullptr;
 421
 422   CHECK(sqlite3_vfs_register(parent_, 1) == SQLITE_OK);
 423   CHECK(sqlite3_vfs_unregister(&mojo_vfs) == SQLITE_OK);
 424 }
 425
 426 filesystem::DirectoryPtr& ScopedMojoFilesystemVFS::GetDirectory() {
 427   return root_directory_;
 428 }
 429
 430 }  // namespace sql