| // Copyright (c) 2017 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "sql/vfs_wrapper.h" |
| |
| #include <algorithm> |
| #include <string> |
| #include <vector> |
| |
| #include "base/check_op.h" |
| #include "base/debug/leak_annotations.h" |
| #include "base/files/file_path.h" |
| #include "base/memory/ptr_util.h" |
| #include "base/metrics/histogram_macros.h" |
| #include "base/notreached.h" |
| #include "base/strings/string_piece.h" |
| #include "build/build_config.h" |
| |
| #if defined(OS_MAC) |
| #include "base/mac/mac_util.h" |
| #endif |
| |
| #if defined(OS_FUCHSIA) |
| #include "sql/vfs_wrapper_fuchsia.h" |
| #endif |
| |
| namespace sql { |
| namespace { |
| |
| // https://www.sqlite.org/vfs.html - documents the overall VFS system. |
| // |
| // https://www.sqlite.org/c3ref/vfs.html - VFS methods. This code tucks the |
| // wrapped VFS pointer into the wrapper's pAppData pointer. |
| // |
| // https://www.sqlite.org/c3ref/file.html - instance of an open file. This code |
| // allocates a VfsFile for this, which contains a pointer to the wrapped file. |
| // Idiomatic SQLite would take the wrapped VFS szOsFile and increase it to store |
| // additional data as a prefix. |
| |
| sqlite3_vfs* GetWrappedVfs(sqlite3_vfs* wrapped_vfs) { |
| return static_cast<sqlite3_vfs*>(wrapped_vfs->pAppData); |
| } |
| |
| VfsFile* AsVfsFile(sqlite3_file* wrapper_file) { |
| return reinterpret_cast<VfsFile*>(wrapper_file); |
| } |
| |
| sqlite3_file* GetWrappedFile(sqlite3_file* wrapper_file) { |
| return AsVfsFile(wrapper_file)->wrapped_file; |
| } |
| |
| int Close(sqlite3_file* sqlite_file) |
| { |
| VfsFile* file = AsVfsFile(sqlite_file); |
| |
| #if defined(OS_FUCHSIA) |
| FuchsiaVfsUnlock(sqlite_file, SQLITE_LOCK_NONE); |
| #endif |
| |
| int r = file->wrapped_file->pMethods->xClose(file->wrapped_file); |
| sqlite3_free(file->wrapped_file); |
| |
| // Memory will be freed with sqlite3_free(), so the destructor needs to be |
| // called explicitly. |
| file->~VfsFile(); |
| memset(file, '\0', sizeof(*file)); |
| return r; |
| } |
| |
| int Read(sqlite3_file* sqlite_file, void* buf, int amt, sqlite3_int64 ofs) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xRead(wrapped_file, buf, amt, ofs); |
| } |
| |
| int Write(sqlite3_file* sqlite_file, const void* buf, int amt, |
| sqlite3_int64 ofs) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xWrite(wrapped_file, buf, amt, ofs); |
| } |
| |
| int Truncate(sqlite3_file* sqlite_file, sqlite3_int64 size) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xTruncate(wrapped_file, size); |
| } |
| |
| int Sync(sqlite3_file* sqlite_file, int flags) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xSync(wrapped_file, flags); |
| } |
| |
| int FileSize(sqlite3_file* sqlite_file, sqlite3_int64* size) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xFileSize(wrapped_file, size); |
| } |
| |
| #if !defined(OS_FUCHSIA) |
| |
| int Lock(sqlite3_file* sqlite_file, int file_lock) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xLock(wrapped_file, file_lock); |
| } |
| |
| int Unlock(sqlite3_file* sqlite_file, int file_lock) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xUnlock(wrapped_file, file_lock); |
| } |
| |
| int CheckReservedLock(sqlite3_file* sqlite_file, int* result) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xCheckReservedLock(wrapped_file, result); |
| } |
| |
| #endif // !defined(OS_FUCHSIA) |
| |
| int FileControl(sqlite3_file* sqlite_file, int op, void* arg) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xFileControl(wrapped_file, op, arg); |
| } |
| |
| int SectorSize(sqlite3_file* sqlite_file) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xSectorSize(wrapped_file); |
| } |
| |
| int DeviceCharacteristics(sqlite3_file* sqlite_file) |
| { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xDeviceCharacteristics(wrapped_file); |
| } |
| |
| int ShmMap(sqlite3_file *sqlite_file, int region, int size, |
| int extend, void volatile **pp) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xShmMap( |
| wrapped_file, region, size, extend, pp); |
| } |
| |
| int ShmLock(sqlite3_file *sqlite_file, int ofst, int n, int flags) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xShmLock(wrapped_file, ofst, n, flags); |
| } |
| |
| void ShmBarrier(sqlite3_file *sqlite_file) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| wrapped_file->pMethods->xShmBarrier(wrapped_file); |
| } |
| |
| int ShmUnmap(sqlite3_file *sqlite_file, int del) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xShmUnmap(wrapped_file, del); |
| } |
| |
| int Fetch(sqlite3_file *sqlite_file, sqlite3_int64 off, int amt, void **pp) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xFetch(wrapped_file, off, amt, pp); |
| } |
| |
| int Unfetch(sqlite3_file *sqlite_file, sqlite3_int64 off, void *p) { |
| sqlite3_file* wrapped_file = GetWrappedFile(sqlite_file); |
| return wrapped_file->pMethods->xUnfetch(wrapped_file, off, p); |
| } |
| |
| int Open(sqlite3_vfs* vfs, const char* file_name, sqlite3_file* wrapper_file, |
| int desired_flags, int* used_flags) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| |
| sqlite3_file* wrapped_file = static_cast<sqlite3_file*>( |
| sqlite3_malloc(wrapped_vfs->szOsFile)); |
| if (!wrapped_file) |
| return SQLITE_NOMEM; |
| |
| // NOTE(shess): SQLite's unixOpen() makes assumptions about the structure of |
| // |file_name|. Do not pass a local copy, here, only the passed-in value. |
| int rc = wrapped_vfs->xOpen(wrapped_vfs, |
| file_name, wrapped_file, |
| desired_flags, used_flags); |
| if (rc != SQLITE_OK) { |
| sqlite3_free(wrapped_file); |
| return rc; |
| } |
| // NOTE(shess): Any early exit from here needs to call xClose() on |
| // |wrapped_file|. |
| |
| #if defined(OS_MAC) |
| // When opening journal files, propagate time-machine exclusion from db. |
| static int kJournalFlags = |
| SQLITE_OPEN_MAIN_JOURNAL | SQLITE_OPEN_TEMP_JOURNAL | |
| SQLITE_OPEN_SUBJOURNAL | SQLITE_OPEN_MASTER_JOURNAL; |
| if (file_name && (desired_flags & kJournalFlags)) { |
| // https://www.sqlite.org/c3ref/vfs.html indicates that the journal path |
| // will have a suffix separated by "-" from the main database file name. |
| base::StringPiece file_name_string_piece(file_name); |
| size_t dash_index = file_name_string_piece.rfind('-'); |
| if (dash_index != base::StringPiece::npos) { |
| base::StringPiece db_name(file_name, dash_index); |
| if (base::mac::GetFileBackupExclusion(base::FilePath(db_name))) { |
| base::mac::SetFileBackupExclusion( |
| base::FilePath(file_name_string_piece)); |
| } |
| } |
| } |
| #endif |
| |
| // |iVersion| determines what methods SQLite may call on the instance. |
| // Having the methods which can't be proxied return an error may cause SQLite |
| // to operate differently than if it didn't call those methods at all. To be |
| // on the safe side, the wrapper sqlite3_io_methods version perfectly matches |
| // the version of the wrapped files. |
| // |
| // At a first glance, it might be tempting to simplify the code by |
| // restricting wrapping support to VFS version 3. However, this might fail on |
| // Mac. |
| // |
| // On Mac, SQLite built with SQLITE_ENABLE_LOCKING_STYLE ends up using a VFS |
| // that dynamically dispatches between a few variants of sqlite3_io_methods, |
| // based on whether the opened database is on a local or on a remote (AFS, |
| // NFS) filesystem. Some variants return a VFS version 1 structure. |
| VfsFile* file = AsVfsFile(wrapper_file); |
| |
| // Call constructor explicitly since the memory is already allocated. |
| new (file) VfsFile(); |
| |
| file->wrapped_file = wrapped_file; |
| |
| #if defined(OS_FUCHSIA) |
| file->file_name = file_name; |
| file->lock_level = SQLITE_LOCK_NONE; |
| #endif |
| |
| if (wrapped_file->pMethods->iVersion == 1) { |
| static const sqlite3_io_methods io_methods = { |
| 1, |
| Close, |
| Read, |
| Write, |
| Truncate, |
| Sync, |
| FileSize, |
| #if !defined(OS_FUCHSIA) |
| Lock, |
| Unlock, |
| CheckReservedLock, |
| #else |
| FuchsiaVfsLock, |
| FuchsiaVfsUnlock, |
| FuchsiaVfsCheckReservedLock, |
| #endif |
| FileControl, |
| SectorSize, |
| DeviceCharacteristics, |
| }; |
| file->methods = &io_methods; |
| } else if (wrapped_file->pMethods->iVersion == 2) { |
| static const sqlite3_io_methods io_methods = { |
| 2, |
| Close, |
| Read, |
| Write, |
| Truncate, |
| Sync, |
| FileSize, |
| #if !defined(OS_FUCHSIA) |
| Lock, |
| Unlock, |
| CheckReservedLock, |
| #else |
| FuchsiaVfsLock, |
| FuchsiaVfsUnlock, |
| FuchsiaVfsCheckReservedLock, |
| #endif |
| FileControl, |
| SectorSize, |
| DeviceCharacteristics, |
| // Methods above are valid for version 1. |
| ShmMap, |
| ShmLock, |
| ShmBarrier, |
| ShmUnmap, |
| }; |
| file->methods = &io_methods; |
| } else { |
| static const sqlite3_io_methods io_methods = { |
| 3, |
| Close, |
| Read, |
| Write, |
| Truncate, |
| Sync, |
| FileSize, |
| #if !defined(OS_FUCHSIA) |
| Lock, |
| Unlock, |
| CheckReservedLock, |
| #else |
| FuchsiaVfsLock, |
| FuchsiaVfsUnlock, |
| FuchsiaVfsCheckReservedLock, |
| #endif |
| FileControl, |
| SectorSize, |
| DeviceCharacteristics, |
| // Methods above are valid for version 1. |
| ShmMap, |
| ShmLock, |
| ShmBarrier, |
| ShmUnmap, |
| // Methods above are valid for version 2. |
| Fetch, |
| Unfetch, |
| }; |
| file->methods = &io_methods; |
| } |
| return SQLITE_OK; |
| } |
| |
| int Delete(sqlite3_vfs* vfs, const char* file_name, int sync_dir) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xDelete(wrapped_vfs, file_name, sync_dir); |
| } |
| |
| int Access(sqlite3_vfs* vfs, const char* file_name, int flag, int* res) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xAccess(wrapped_vfs, file_name, flag, res); |
| } |
| |
| int FullPathname(sqlite3_vfs* vfs, const char* relative_path, |
| int buf_size, char* absolute_path) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xFullPathname( |
| wrapped_vfs, relative_path, buf_size, absolute_path); |
| } |
| |
| int Randomness(sqlite3_vfs* vfs, int buf_size, char* buffer) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xRandomness(wrapped_vfs, buf_size, buffer); |
| } |
| |
| int Sleep(sqlite3_vfs* vfs, int microseconds) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xSleep(wrapped_vfs, microseconds); |
| } |
| |
| int GetLastError(sqlite3_vfs* vfs, int e, char* s) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xGetLastError(wrapped_vfs, e, s); |
| } |
| |
| int CurrentTimeInt64(sqlite3_vfs* vfs, sqlite3_int64* now) { |
| sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs); |
| return wrapped_vfs->xCurrentTimeInt64(wrapped_vfs, now); |
| } |
| |
| } // namespace |
| |
| sqlite3_vfs* VFSWrapper() { |
| const char* kVFSName = "VFSWrapper"; |
| |
| // Return existing version if already registered. |
| { |
| sqlite3_vfs* vfs = sqlite3_vfs_find(kVFSName); |
| if (vfs) |
| return vfs; |
| } |
| |
| // Get the default VFS on all platforms except Fuchsia. |
| const char* base_vfs_name = nullptr; |
| #if defined(OS_FUCHSIA) |
| base_vfs_name = "unix-none"; |
| #endif |
| sqlite3_vfs* wrapped_vfs = sqlite3_vfs_find(base_vfs_name); |
| |
| // Give up if there is no VFS implementation for the current platform. |
| if (!wrapped_vfs) { |
| NOTREACHED(); |
| return nullptr; |
| } |
| |
| std::unique_ptr<sqlite3_vfs, std::function<void(sqlite3_vfs*)>> wrapper_vfs( |
| static_cast<sqlite3_vfs*>(sqlite3_malloc(sizeof(sqlite3_vfs))), |
| [](sqlite3_vfs* v) { |
| sqlite3_free(v); |
| }); |
| memset(wrapper_vfs.get(), '\0', sizeof(sqlite3_vfs)); |
| |
| // VFS implementations should always work with a SQLite that only knows about |
| // earlier versions. |
| constexpr int kSqliteVfsApiVersion = 3; |
| wrapper_vfs->iVersion = kSqliteVfsApiVersion; |
| |
| // All the SQLite VFS implementations used by Chrome should support the |
| // version proxied here. |
| DCHECK_GE(wrapped_vfs->iVersion, kSqliteVfsApiVersion); |
| |
| // Caller of xOpen() allocates this much space. |
| wrapper_vfs->szOsFile = sizeof(VfsFile); |
| |
| wrapper_vfs->mxPathname = wrapped_vfs->mxPathname; |
| wrapper_vfs->pNext = nullptr; // Field used by SQLite. |
| wrapper_vfs->zName = kVFSName; |
| |
| // Keep a reference to the wrapped vfs for use in methods. |
| wrapper_vfs->pAppData = wrapped_vfs; |
| |
| // VFS methods. |
| wrapper_vfs->xOpen = &Open; |
| wrapper_vfs->xDelete = &Delete; |
| wrapper_vfs->xAccess = &Access; |
| wrapper_vfs->xFullPathname = &FullPathname; |
| |
| // SQLite's dynamic extension loading is disabled in Chrome. Not proxying |
| // these methods lets us ship less logic and provides a tiny bit of extra |
| // security, as we know for sure that SQLite will not dynamically load code. |
| wrapper_vfs->xDlOpen = nullptr; |
| wrapper_vfs->xDlError = nullptr; |
| wrapper_vfs->xDlSym = nullptr; |
| wrapper_vfs->xDlClose = nullptr; |
| |
| wrapper_vfs->xRandomness = &Randomness; |
| wrapper_vfs->xSleep = &Sleep; |
| |
| // |xCurrentTime| is null when SQLite is built with SQLITE_OMIT_DEPRECATED, so |
| // it does not need to be proxied. |
| wrapper_vfs->xCurrentTime = nullptr; |
| |
| wrapper_vfs->xGetLastError = &GetLastError; |
| |
| // The methods above are in version 1 of SQLite's VFS API. |
| |
| DCHECK(wrapped_vfs->xCurrentTimeInt64 != nullptr); |
| wrapper_vfs->xCurrentTimeInt64 = &CurrentTimeInt64; |
| |
| // The methods above are in version 2 of SQLite's VFS API. |
| |
| // The VFS system call interception API is intended for very low-level SQLite |
| // testing and tweaks. Proxying these methods is not necessary because Chrome |
| // does not do very low-level SQLite testing, and the VFS wrapper supports all |
| // the needed tweaks. |
| wrapper_vfs->xSetSystemCall = nullptr; |
| wrapper_vfs->xGetSystemCall = nullptr; |
| wrapper_vfs->xNextSystemCall = nullptr; |
| |
| // The methods above are in version 3 of sqlite_vfs. |
| |
| if (SQLITE_OK == sqlite3_vfs_register(wrapper_vfs.get(), 0)) { |
| ANNOTATE_LEAKING_OBJECT_PTR(wrapper_vfs.get()); |
| wrapper_vfs.release(); |
| } |
| |
| return sqlite3_vfs_find(kVFSName); |
| } |
| |
| } // namespace sql |