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// Copyright (c) 2012 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/connection.h"
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <utility>
#include "base/bind.h"
#include "base/debug/alias.h"
#include "base/debug/dump_without_crashing.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/format_macros.h"
#include "base/json/json_file_value_serializer.h"
#include "base/lazy_instance.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/sparse_histogram.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/synchronization/lock.h"
#include "base/threading/sequenced_task_runner_handle.h"
#include "base/trace_event/memory_dump_manager.h"
#include "build/build_config.h"
#include "sql/connection_memory_dump_provider.h"
#include "sql/meta_table.h"
#include "sql/statement.h"
#include "sql/vfs_wrapper.h"
#include "third_party/sqlite/sqlite3.h"
#if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
#include "base/ios/ios_util.h"
#include "third_party/sqlite/src/ext/icu/sqliteicu.h"
#endif
namespace {
// Spin for up to a second waiting for the lock to clear when setting
// up the database.
// TODO(shess): Better story on this. http://crbug.com/56559
const int kBusyTimeoutSeconds = 1;
class ScopedBusyTimeout {
public:
explicit ScopedBusyTimeout(sqlite3* db)
: db_(db) {
}
~ScopedBusyTimeout() {
sqlite3_busy_timeout(db_, 0);
}
int SetTimeout(base::TimeDelta timeout) {
DCHECK_LT(timeout.InMilliseconds(), INT_MAX);
return sqlite3_busy_timeout(db_,
static_cast<int>(timeout.InMilliseconds()));
}
private:
sqlite3* db_;
};
// Helper to "safely" enable writable_schema. No error checking
// because it is reasonable to just forge ahead in case of an error.
// If turning it on fails, then most likely nothing will work, whereas
// if turning it off fails, it only matters if some code attempts to
// continue working with the database and tries to modify the
// sqlite_master table (none of our code does this).
class ScopedWritableSchema {
public:
explicit ScopedWritableSchema(sqlite3* db)
: db_(db) {
sqlite3_exec(db_, "PRAGMA writable_schema=1", NULL, NULL, NULL);
}
~ScopedWritableSchema() {
sqlite3_exec(db_, "PRAGMA writable_schema=0", NULL, NULL, NULL);
}
private:
sqlite3* db_;
};
// Helper to wrap the sqlite3_backup_*() step of Raze(). Return
// SQLite error code from running the backup step.
int BackupDatabase(sqlite3* src, sqlite3* dst, const char* db_name) {
DCHECK_NE(src, dst);
sqlite3_backup* backup = sqlite3_backup_init(dst, db_name, src, db_name);
if (!backup) {
// Since this call only sets things up, this indicates a gross
// error in SQLite.
DLOG(DCHECK) << "Unable to start sqlite3_backup(): " << sqlite3_errmsg(dst);
return sqlite3_errcode(dst);
}
// -1 backs up the entire database.
int rc = sqlite3_backup_step(backup, -1);
int pages = sqlite3_backup_pagecount(backup);
sqlite3_backup_finish(backup);
// If successful, exactly one page should have been backed up. If
// this breaks, check this function to make sure assumptions aren't
// being broken.
if (rc == SQLITE_DONE)
DCHECK_EQ(pages, 1);
return rc;
}
// Be very strict on attachment point. SQLite can handle a much wider
// character set with appropriate quoting, but Chromium code should
// just use clean names to start with.
bool ValidAttachmentPoint(const char* attachment_point) {
for (size_t i = 0; attachment_point[i]; ++i) {
if (!(base::IsAsciiDigit(attachment_point[i]) ||
base::IsAsciiAlpha(attachment_point[i]) ||
attachment_point[i] == '_')) {
return false;
}
}
return true;
}
void RecordSqliteMemory10Min() {
const int64_t used = sqlite3_memory_used();
UMA_HISTOGRAM_COUNTS("Sqlite.MemoryKB.TenMinutes", used / 1024);
}
void RecordSqliteMemoryHour() {
const int64_t used = sqlite3_memory_used();
UMA_HISTOGRAM_COUNTS("Sqlite.MemoryKB.OneHour", used / 1024);
}
void RecordSqliteMemoryDay() {
const int64_t used = sqlite3_memory_used();
UMA_HISTOGRAM_COUNTS("Sqlite.MemoryKB.OneDay", used / 1024);
}
void RecordSqliteMemoryWeek() {
const int64_t used = sqlite3_memory_used();
UMA_HISTOGRAM_COUNTS("Sqlite.MemoryKB.OneWeek", used / 1024);
}
// SQLite automatically calls sqlite3_initialize() lazily, but
// sqlite3_initialize() uses double-checked locking and thus can have
// data races.
//
// TODO(shess): Another alternative would be to have
// sqlite3_initialize() called as part of process bring-up. If this
// is changed, remove the dynamic_annotations dependency in sql.gyp.
base::LazyInstance<base::Lock>::Leaky
g_sqlite_init_lock = LAZY_INSTANCE_INITIALIZER;
void InitializeSqlite() {
base::AutoLock lock(g_sqlite_init_lock.Get());
static bool first_call = true;
if (first_call) {
sqlite3_initialize();
// Schedule callback to record memory footprint histograms at 10m, 1h, and
// 1d. There may not be a registered task runner in tests.
if (base::SequencedTaskRunnerHandle::IsSet()) {
base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE, base::Bind(&RecordSqliteMemory10Min),
base::TimeDelta::FromMinutes(10));
base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE, base::Bind(&RecordSqliteMemoryHour),
base::TimeDelta::FromHours(1));
base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE, base::Bind(&RecordSqliteMemoryDay),
base::TimeDelta::FromDays(1));
base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE, base::Bind(&RecordSqliteMemoryWeek),
base::TimeDelta::FromDays(7));
}
first_call = false;
}
}
// Helper to get the sqlite3_file* associated with the "main" database.
int GetSqlite3File(sqlite3* db, sqlite3_file** file) {
*file = NULL;
int rc = sqlite3_file_control(db, NULL, SQLITE_FCNTL_FILE_POINTER, file);
if (rc != SQLITE_OK)
return rc;
// TODO(shess): NULL in file->pMethods has been observed on android_dbg
// content_unittests, even though it should not be possible.
// http://crbug.com/329982
if (!*file || !(*file)->pMethods)
return SQLITE_ERROR;
return rc;
}
// Convenience to get the sqlite3_file* and the size for the "main" database.
int GetSqlite3FileAndSize(sqlite3* db,
sqlite3_file** file, sqlite3_int64* db_size) {
int rc = GetSqlite3File(db, file);
if (rc != SQLITE_OK)
return rc;
return (*file)->pMethods->xFileSize(*file, db_size);
}
// This should match UMA_HISTOGRAM_MEDIUM_TIMES().
base::HistogramBase* GetMediumTimeHistogram(const std::string& name) {
return base::Histogram::FactoryTimeGet(
name,
base::TimeDelta::FromMilliseconds(10),
base::TimeDelta::FromMinutes(3),
50,
base::HistogramBase::kUmaTargetedHistogramFlag);
}
std::string AsUTF8ForSQL(const base::FilePath& path) {
#if defined(OS_WIN)
return base::WideToUTF8(path.value());
#elif defined(OS_POSIX)
return path.value();
#endif
}
} // namespace
namespace sql {
// static
Connection::ErrorExpecterCallback* Connection::current_expecter_cb_ = NULL;
// static
bool Connection::IsExpectedSqliteError(int error) {
if (!current_expecter_cb_)
return false;
return current_expecter_cb_->Run(error);
}
void Connection::ReportDiagnosticInfo(int extended_error, Statement* stmt) {
AssertIOAllowed();
std::string debug_info = GetDiagnosticInfo(extended_error, stmt);
if (!debug_info.empty() && RegisterIntentToUpload()) {
char debug_buf[2000];
base::strlcpy(debug_buf, debug_info.c_str(), arraysize(debug_buf));
base::debug::Alias(&debug_buf);
base::debug::DumpWithoutCrashing();
}
}
// static
void Connection::SetErrorExpecter(Connection::ErrorExpecterCallback* cb) {
CHECK(current_expecter_cb_ == NULL);
current_expecter_cb_ = cb;
}
// static
void Connection::ResetErrorExpecter() {
CHECK(current_expecter_cb_);
current_expecter_cb_ = NULL;
}
bool StatementID::operator<(const StatementID& other) const {
if (number_ != other.number_)
return number_ < other.number_;
return strcmp(str_, other.str_) < 0;
}
Connection::StatementRef::StatementRef(Connection* connection,
sqlite3_stmt* stmt,
bool was_valid)
: connection_(connection),
stmt_(stmt),
was_valid_(was_valid) {
if (connection)
connection_->StatementRefCreated(this);
}
Connection::StatementRef::~StatementRef() {
if (connection_)
connection_->StatementRefDeleted(this);
Close(false);
}
void Connection::StatementRef::Close(bool forced) {
if (stmt_) {
// Call to AssertIOAllowed() cannot go at the beginning of the function
// because Close() is called unconditionally from destructor to clean
// connection_. And if this is inactive statement this won't cause any
// disk access and destructor most probably will be called on thread
// not allowing disk access.
// TODO(paivanof@gmail.com): This should move to the beginning
// of the function. http://crbug.com/136655.
AssertIOAllowed();
sqlite3_finalize(stmt_);
stmt_ = NULL;
}
connection_ = NULL; // The connection may be getting deleted.
// Forced close is expected to happen from a statement error
// handler. In that case maintain the sense of |was_valid_| which
// previously held for this ref.
was_valid_ = was_valid_ && forced;
}
Connection::Connection()
: db_(NULL),
page_size_(0),
cache_size_(0),
exclusive_locking_(false),
restrict_to_user_(false),
transaction_nesting_(0),
needs_rollback_(false),
in_memory_(false),
poisoned_(false),
mmap_alt_status_(false),
mmap_disabled_(false),
mmap_enabled_(false),
total_changes_at_last_release_(0),
stats_histogram_(NULL),
commit_time_histogram_(NULL),
autocommit_time_histogram_(NULL),
update_time_histogram_(NULL),
query_time_histogram_(NULL),
clock_(new TimeSource()) {
}
Connection::~Connection() {
Close();
}
void Connection::RecordEvent(Events event, size_t count) {
for (size_t i = 0; i < count; ++i) {
UMA_HISTOGRAM_ENUMERATION("Sqlite.Stats", event, EVENT_MAX_VALUE);
}
if (stats_histogram_) {
for (size_t i = 0; i < count; ++i) {
stats_histogram_->Add(event);
}
}
}
void Connection::RecordCommitTime(const base::TimeDelta& delta) {
RecordUpdateTime(delta);
UMA_HISTOGRAM_MEDIUM_TIMES("Sqlite.CommitTime", delta);
if (commit_time_histogram_)
commit_time_histogram_->AddTime(delta);
}
void Connection::RecordAutoCommitTime(const base::TimeDelta& delta) {
RecordUpdateTime(delta);
UMA_HISTOGRAM_MEDIUM_TIMES("Sqlite.AutoCommitTime", delta);
if (autocommit_time_histogram_)
autocommit_time_histogram_->AddTime(delta);
}
void Connection::RecordUpdateTime(const base::TimeDelta& delta) {
RecordQueryTime(delta);
UMA_HISTOGRAM_MEDIUM_TIMES("Sqlite.UpdateTime", delta);
if (update_time_histogram_)
update_time_histogram_->AddTime(delta);
}
void Connection::RecordQueryTime(const base::TimeDelta& delta) {
UMA_HISTOGRAM_MEDIUM_TIMES("Sqlite.QueryTime", delta);
if (query_time_histogram_)
query_time_histogram_->AddTime(delta);
}
void Connection::RecordTimeAndChanges(
const base::TimeDelta& delta, bool read_only) {
if (read_only) {
RecordQueryTime(delta);
} else {
const int changes = sqlite3_changes(db_);
if (sqlite3_get_autocommit(db_)) {
RecordAutoCommitTime(delta);
RecordEvent(EVENT_CHANGES_AUTOCOMMIT, changes);
} else {
RecordUpdateTime(delta);
RecordEvent(EVENT_CHANGES, changes);
}
}
}
bool Connection::Open(const base::FilePath& path) {
if (!histogram_tag_.empty()) {
int64_t size_64 = 0;
if (base::GetFileSize(path, &size_64)) {
size_t sample = static_cast<size_t>(size_64 / 1024);
std::string full_histogram_name = "Sqlite.SizeKB." + histogram_tag_;
base::HistogramBase* histogram =
base::Histogram::FactoryGet(
full_histogram_name, 1, 1000000, 50,
base::HistogramBase::kUmaTargetedHistogramFlag);
if (histogram)
histogram->Add(sample);
UMA_HISTOGRAM_COUNTS("Sqlite.SizeKB", sample);
}
}
return OpenInternal(AsUTF8ForSQL(path), RETRY_ON_POISON);
}
bool Connection::OpenInMemory() {
in_memory_ = true;
return OpenInternal(":memory:", NO_RETRY);
}
bool Connection::OpenTemporary() {
return OpenInternal("", NO_RETRY);
}
void Connection::CloseInternal(bool forced) {
// TODO(shess): Calling "PRAGMA journal_mode = DELETE" at this point
// will delete the -journal file. For ChromiumOS or other more
// embedded systems, this is probably not appropriate, whereas on
// desktop it might make some sense.
// sqlite3_close() needs all prepared statements to be finalized.
// Release cached statements.
statement_cache_.clear();
// With cached statements released, in-use statements will remain.
// Closing the database while statements are in use is an API
// violation, except for forced close (which happens from within a
// statement's error handler).
DCHECK(forced || open_statements_.empty());
// Deactivate any outstanding statements so sqlite3_close() works.
for (StatementRefSet::iterator i = open_statements_.begin();
i != open_statements_.end(); ++i)
(*i)->Close(forced);
open_statements_.clear();
if (db_) {
// Call to AssertIOAllowed() cannot go at the beginning of the function
// because Close() must be called from destructor to clean
// statement_cache_, it won't cause any disk access and it most probably
// will happen on thread not allowing disk access.
// TODO(paivanof@gmail.com): This should move to the beginning
// of the function. http://crbug.com/136655.
AssertIOAllowed();
// Reseting acquires a lock to ensure no dump is happening on the database
// at the same time. Unregister takes ownership of provider and it is safe
// since the db is reset. memory_dump_provider_ could be null if db_ was
// poisoned.
if (memory_dump_provider_) {
memory_dump_provider_->ResetDatabase();
base::trace_event::MemoryDumpManager::GetInstance()
->UnregisterAndDeleteDumpProviderSoon(
std::move(memory_dump_provider_));
}
int rc = sqlite3_close(db_);
if (rc != SQLITE_OK) {
base::UmaHistogramSparse("Sqlite.CloseFailure", rc);
DLOG(DCHECK) << "sqlite3_close failed: " << GetErrorMessage();
}
}
db_ = NULL;
}
void Connection::Close() {
// If the database was already closed by RazeAndClose(), then no
// need to close again. Clear the |poisoned_| bit so that incorrect
// API calls are caught.
if (poisoned_) {
poisoned_ = false;
return;
}
CloseInternal(false);
}
void Connection::Preload() {
AssertIOAllowed();
if (!db_) {
DCHECK(poisoned_) << "Cannot preload null db";
return;
}
// Use local settings if provided, otherwise use documented defaults. The
// actual results could be fetching via PRAGMA calls.
const int page_size = page_size_ ? page_size_ : 1024;
sqlite3_int64 preload_size = page_size * (cache_size_ ? cache_size_ : 2000);
if (preload_size < 1)
return;
sqlite3_file* file = NULL;
sqlite3_int64 file_size = 0;
int rc = GetSqlite3FileAndSize(db_, &file, &file_size);
if (rc != SQLITE_OK)
return;
// Don't preload more than the file contains.
if (preload_size > file_size)
preload_size = file_size;
std::unique_ptr<char[]> buf(new char[page_size]);
for (sqlite3_int64 pos = 0; pos < preload_size; pos += page_size) {
rc = file->pMethods->xRead(file, buf.get(), page_size, pos);
// TODO(shess): Consider calling OnSqliteError().
if (rc != SQLITE_OK)
return;
}
}
// SQLite keeps unused pages associated with a connection in a cache. It asks
// the cache for pages by an id, and if the page is present and the database is
// unchanged, it considers the content of the page valid and doesn't read it
// from disk. When memory-mapped I/O is enabled, on read SQLite uses page
// structures created from the memory map data before consulting the cache. On
// write SQLite creates a new in-memory page structure, copies the data from the
// memory map, and later writes it, releasing the updated page back to the
// cache.
//
// This means that in memory-mapped mode, the contents of the cached pages are
// not re-used for reads, but they are re-used for writes if the re-written page
// is still in the cache. The implementation of sqlite3_db_release_memory() as
// of SQLite 3.8.7.4 frees all pages from pcaches associated with the
// connection, so it should free these pages.
//
// Unfortunately, the zero page is also freed. That page is never accessed
// using memory-mapped I/O, and the cached copy can be re-used after verifying
// the file change counter on disk. Also, fresh pages from cache receive some
// pager-level initialization before they can be used. Since the information
// involved will immediately be accessed in various ways, it is unclear if the
// additional overhead is material, or just moving processor cache effects
// around.
//
// TODO(shess): It would be better to release the pages immediately when they
// are no longer needed. This would basically happen after SQLite commits a
// transaction. I had implemented a pcache wrapper to do this, but it involved
// layering violations, and it had to be setup before any other sqlite call,
// which was brittle. Also, for large files it would actually make sense to
// maintain the existing pcache behavior for blocks past the memory-mapped
// segment. I think drh would accept a reasonable implementation of the overall
// concept for upstreaming to SQLite core.
//
// TODO(shess): Another possibility would be to set the cache size small, which
// would keep the zero page around, plus some pre-initialized pages, and SQLite
// can manage things. The downside is that updates larger than the cache would
// spill to the journal. That could be compensated by setting cache_spill to
// false. The downside then is that it allows open-ended use of memory for
// large transactions.
//
// TODO(shess): The TrimMemory() trick of bouncing the cache size would also
// work. There could be two prepared statements, one for cache_size=1 one for
// cache_size=goal.
void Connection::ReleaseCacheMemoryIfNeeded(bool implicit_change_performed) {
// The database could have been closed during a transaction as part of error
// recovery.
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return;
}
// If memory-mapping is not enabled, the page cache helps performance.
if (!mmap_enabled_)
return;
// On caller request, force the change comparison to fail. Done before the
// transaction-nesting test so that the signal can carry to transaction
// commit.
if (implicit_change_performed)
--total_changes_at_last_release_;
// Cached pages may be re-used within the same transaction.
if (transaction_nesting())
return;
// If no changes have been made, skip flushing. This allows the first page of
// the database to remain in cache across multiple reads.
const int total_changes = sqlite3_total_changes(db_);
if (total_changes == total_changes_at_last_release_)
return;
total_changes_at_last_release_ = total_changes;
sqlite3_db_release_memory(db_);
}
base::FilePath Connection::DbPath() const {
if (!is_open())
return base::FilePath();
const char* path = sqlite3_db_filename(db_, "main");
const base::StringPiece db_path(path);
#if defined(OS_WIN)
return base::FilePath(base::UTF8ToWide(db_path));
#elif defined(OS_POSIX)
return base::FilePath(db_path);
#else
NOTREACHED();
return base::FilePath();
#endif
}
// Data is persisted in a file shared between databases in the same directory.
// The "sqlite-diag" file contains a dictionary with the version number, and an
// array of histogram tags for databases which have been dumped.
bool Connection::RegisterIntentToUpload() const {
static const char* kVersionKey = "version";
static const char* kDiagnosticDumpsKey = "DiagnosticDumps";
static int kVersion = 1;
AssertIOAllowed();
if (histogram_tag_.empty())
return false;
if (!is_open())
return false;
if (in_memory_)
return false;
const base::FilePath db_path = DbPath();
if (db_path.empty())
return false;
// Put the collection of diagnostic data next to the databases. In most
// cases, this is the profile directory, but safe-browsing stores a Cookies
// file in the directory above the profile directory.
base::FilePath breadcrumb_path(
db_path.DirName().Append(FILE_PATH_LITERAL("sqlite-diag")));
// Lock against multiple updates to the diagnostics file. This code should
// seldom be called in the first place, and when called it should seldom be
// called for multiple databases, and when called for multiple databases there
// is _probably_ something systemic wrong with the user's system. So the lock
// should never be contended, but when it is the database experience is
// already bad.
base::AutoLock lock(g_sqlite_init_lock.Get());
std::unique_ptr<base::Value> root;
if (!base::PathExists(breadcrumb_path)) {
std::unique_ptr<base::DictionaryValue> root_dict(
new base::DictionaryValue());
root_dict->SetInteger(kVersionKey, kVersion);
std::unique_ptr<base::ListValue> dumps(new base::ListValue);
dumps->AppendString(histogram_tag_);
root_dict->Set(kDiagnosticDumpsKey, std::move(dumps));
root = std::move(root_dict);
} else {
// Failure to read a valid dictionary implies that something is going wrong
// on the system.
JSONFileValueDeserializer deserializer(breadcrumb_path);
std::unique_ptr<base::Value> read_root(
deserializer.Deserialize(nullptr, nullptr));
if (!read_root.get())
return false;
std::unique_ptr<base::DictionaryValue> root_dict =
base::DictionaryValue::From(std::move(read_root));
if (!root_dict)
return false;
// Don't upload if the version is missing or newer.
int version = 0;
if (!root_dict->GetInteger(kVersionKey, &version) || version > kVersion)
return false;
base::ListValue* dumps = nullptr;
if (!root_dict->GetList(kDiagnosticDumpsKey, &dumps))
return false;
const size_t size = dumps->GetSize();
for (size_t i = 0; i < size; ++i) {
std::string s;
// Don't upload if the value isn't a string, or indicates a prior upload.
if (!dumps->GetString(i, &s) || s == histogram_tag_)
return false;
}
// Record intention to proceed with upload.
dumps->AppendString(histogram_tag_);
root = std::move(root_dict);
}
const base::FilePath breadcrumb_new =
breadcrumb_path.AddExtension(FILE_PATH_LITERAL("new"));
base::DeleteFile(breadcrumb_new, false);
// No upload if the breadcrumb file cannot be updated.
// TODO(shess): Consider ImportantFileWriter::WriteFileAtomically() to land
// the data on disk. For now, losing the data is not a big problem, so the
// sync overhead would probably not be worth it.
JSONFileValueSerializer serializer(breadcrumb_new);
if (!serializer.Serialize(*root))
return false;
if (!base::PathExists(breadcrumb_new))
return false;
if (!base::ReplaceFile(breadcrumb_new, breadcrumb_path, nullptr)) {
base::DeleteFile(breadcrumb_new, false);
return false;
}
return true;
}
std::string Connection::CollectErrorInfo(int error, Statement* stmt) const {
// Buffer for accumulating debugging info about the error. Place
// more-relevant information earlier, in case things overflow the
// fixed-size reporting buffer.
std::string debug_info;
// The error message from the failed operation.
base::StringAppendF(&debug_info, "db error: %d/%s\n",
GetErrorCode(), GetErrorMessage());
// TODO(shess): |error| and |GetErrorCode()| should always be the same, but
// reading code does not entirely convince me. Remove if they turn out to be
// the same.
if (error != GetErrorCode())
base::StringAppendF(&debug_info, "reported error: %d\n", error);
// System error information. Interpretation of Windows errors is different
// from posix.
#if defined(OS_WIN)
base::StringAppendF(&debug_info, "LastError: %d\n", GetLastErrno());
#elif defined(OS_POSIX)
base::StringAppendF(&debug_info, "errno: %d\n", GetLastErrno());
#else
NOTREACHED(); // Add appropriate log info.
#endif
if (stmt) {
base::StringAppendF(&debug_info, "statement: %s\n",
stmt->GetSQLStatement());
} else {
base::StringAppendF(&debug_info, "statement: NULL\n");
}
// SQLITE_ERROR often indicates some sort of mismatch between the statement
// and the schema, possibly due to a failed schema migration.
if (error == SQLITE_ERROR) {
const char* kVersionSql = "SELECT value FROM meta WHERE key = 'version'";
sqlite3_stmt* s;
int rc = sqlite3_prepare_v2(db_, kVersionSql, -1, &s, nullptr);
if (rc == SQLITE_OK) {
rc = sqlite3_step(s);
if (rc == SQLITE_ROW) {
base::StringAppendF(&debug_info, "version: %d\n",
sqlite3_column_int(s, 0));
} else if (rc == SQLITE_DONE) {
debug_info += "version: none\n";
} else {
base::StringAppendF(&debug_info, "version: error %d\n", rc);
}
sqlite3_finalize(s);
} else {
base::StringAppendF(&debug_info, "version: prepare error %d\n", rc);
}
debug_info += "schema:\n";
// sqlite_master has columns:
// type - "index" or "table".
// name - name of created element.
// tbl_name - name of element, or target table in case of index.
// rootpage - root page of the element in database file.
// sql - SQL to create the element.
// In general, the |sql| column is sufficient to derive the other columns.
// |rootpage| is not interesting for debugging, without the contents of the
// database. The COALESCE is because certain automatic elements will have a
// |name| but no |sql|,
const char* kSchemaSql = "SELECT COALESCE(sql, name) FROM sqlite_master";
rc = sqlite3_prepare_v2(db_, kSchemaSql, -1, &s, nullptr);
if (rc == SQLITE_OK) {
while ((rc = sqlite3_step(s)) == SQLITE_ROW) {
base::StringAppendF(&debug_info, "%s\n", sqlite3_column_text(s, 0));
}
if (rc != SQLITE_DONE)
base::StringAppendF(&debug_info, "error %d\n", rc);
sqlite3_finalize(s);
} else {
base::StringAppendF(&debug_info, "prepare error %d\n", rc);
}
}
return debug_info;
}
// TODO(shess): Since this is only called in an error situation, it might be
// prudent to rewrite in terms of SQLite API calls, and mark the function const.
std::string Connection::CollectCorruptionInfo() {
AssertIOAllowed();
// If the file cannot be accessed it is unlikely that an integrity check will
// turn up actionable information.
const base::FilePath db_path = DbPath();
int64_t db_size = -1;
if (!base::GetFileSize(db_path, &db_size) || db_size < 0)
return std::string();
// Buffer for accumulating debugging info about the error. Place
// more-relevant information earlier, in case things overflow the
// fixed-size reporting buffer.
std::string debug_info;
base::StringAppendF(&debug_info, "SQLITE_CORRUPT, db size %" PRId64 "\n",
db_size);
// Only check files up to 8M to keep things from blocking too long.
const int64_t kMaxIntegrityCheckSize = 8192 * 1024;
if (db_size > kMaxIntegrityCheckSize) {
debug_info += "integrity_check skipped due to size\n";
} else {
std::vector<std::string> messages;
// TODO(shess): FullIntegrityCheck() splits into a vector while this joins
// into a string. Probably should be refactored.
const base::TimeTicks before = base::TimeTicks::Now();
FullIntegrityCheck(&messages);
base::StringAppendF(
&debug_info,
"integrity_check %" PRId64 " ms, %" PRIuS " records:\n",
(base::TimeTicks::Now() - before).InMilliseconds(),
messages.size());
// SQLite returns up to 100 messages by default, trim deeper to
// keep close to the 2000-character size limit for dumping.
const size_t kMaxMessages = 20;
for (size_t i = 0; i < kMaxMessages && i < messages.size(); ++i) {
base::StringAppendF(&debug_info, "%s\n", messages[i].c_str());
}
}
return debug_info;
}
bool Connection::GetMmapAltStatus(int64_t* status) {
// The [meta] version uses a missing table as a signal for a fresh database.
// That will not work for the view, which would not exist in either a new or
// an existing database. A new database _should_ be only one page long, so
// just don't bother optimizing this case (start at offset 0).
// TODO(shess): Could the [meta] case also get simpler, then?
if (!DoesViewExist("MmapStatus")) {
*status = 0;
return true;
}
const char* kMmapStatusSql = "SELECT * FROM MmapStatus";
Statement s(GetUniqueStatement(kMmapStatusSql));
if (s.Step())
*status = s.ColumnInt64(0);
return s.Succeeded();
}
bool Connection::SetMmapAltStatus(int64_t status) {
if (!BeginTransaction())
return false;
// View may not exist on first run.
if (!Execute("DROP VIEW IF EXISTS MmapStatus")) {
RollbackTransaction();
return false;
}
// Views live in the schema, so they cannot be parameterized. For an integer
// value, this construct should be safe from SQL injection, if the value
// becomes more complicated use "SELECT quote(?)" to generate a safe quoted
// value.
const std::string createViewSql =
base::StringPrintf("CREATE VIEW MmapStatus (value) AS SELECT %" PRId64,
status);
if (!Execute(createViewSql.c_str())) {
RollbackTransaction();
return false;
}
return CommitTransaction();
}
size_t Connection::GetAppropriateMmapSize() {
AssertIOAllowed();
#if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
if (!base::ios::IsRunningOnIOS10OrLater()) {
// iOS SQLite does not support memory mapping.
return 0;
}
#endif
// How much to map if no errors are found. 50MB encompasses the 99th
// percentile of Chrome databases in the wild, so this should be good.
const size_t kMmapEverything = 256 * 1024 * 1024;
// Progress information is tracked in the [meta] table for databases which use
// sql::MetaTable, otherwise it is tracked in a special view.
// TODO(shess): Move all cases to the view implementation.
int64_t mmap_ofs = 0;
if (mmap_alt_status_) {
if (!GetMmapAltStatus(&mmap_ofs)) {
RecordOneEvent(EVENT_MMAP_STATUS_FAILURE_READ);
return 0;
}
} else {
// If [meta] doesn't exist, yet, it's a new database, assume the best.
// sql::MetaTable::Init() will preload kMmapSuccess.
if (!MetaTable::DoesTableExist(this)) {
RecordOneEvent(EVENT_MMAP_META_MISSING);
return kMmapEverything;
}
if (!MetaTable::GetMmapStatus(this, &mmap_ofs)) {
RecordOneEvent(EVENT_MMAP_META_FAILURE_READ);
return 0;
}
}
// Database read failed in the past, don't memory map.
if (mmap_ofs == MetaTable::kMmapFailure) {
RecordOneEvent(EVENT_MMAP_FAILED);
return 0;
} else if (mmap_ofs != MetaTable::kMmapSuccess) {
// Continue reading from previous offset.
DCHECK_GE(mmap_ofs, 0);
// TODO(shess): Could this reading code be shared with Preload()? It would
// require locking twice (this code wouldn't be able to access |db_size| so
// the helper would have to return amount read).
// Read more of the database looking for errors. The VFS interface is used
// to assure that the reads are valid for SQLite. |g_reads_allowed| is used
// to limit checking to 20MB per run of Chromium.
sqlite3_file* file = NULL;
sqlite3_int64 db_size = 0;
if (SQLITE_OK != GetSqlite3FileAndSize(db_, &file, &db_size)) {
RecordOneEvent(EVENT_MMAP_VFS_FAILURE);
return 0;
}
// Read the data left, or |g_reads_allowed|, whichever is smaller.
// |g_reads_allowed| limits the total amount of I/O to spend verifying data
// in a single Chromium run.
sqlite3_int64 amount = db_size - mmap_ofs;
if (amount < 0)
amount = 0;
if (amount > 0) {
base::AutoLock lock(g_sqlite_init_lock.Get());
static sqlite3_int64 g_reads_allowed = 20 * 1024 * 1024;
if (g_reads_allowed < amount)
amount = g_reads_allowed;
g_reads_allowed -= amount;
}
// |amount| can be <= 0 if |g_reads_allowed| ran out of quota, or if the
// database was truncated after a previous pass.
if (amount <= 0 && mmap_ofs < db_size) {
DCHECK_EQ(0, amount);
RecordOneEvent(EVENT_MMAP_SUCCESS_NO_PROGRESS);
} else {
static const int kPageSize = 4096;
char buf[kPageSize];
while (amount > 0) {
int rc = file->pMethods->xRead(file, buf, sizeof(buf), mmap_ofs);
if (rc == SQLITE_OK) {
mmap_ofs += sizeof(buf);
amount -= sizeof(buf);
} else if (rc == SQLITE_IOERR_SHORT_READ) {
// Reached EOF for a database with page size < |kPageSize|.
mmap_ofs = db_size;
break;
} else {
// TODO(shess): Consider calling OnSqliteError().
mmap_ofs = MetaTable::kMmapFailure;
break;
}
}
// Log these events after update to distinguish meta update failure.
Events event;
if (mmap_ofs >= db_size) {
mmap_ofs = MetaTable::kMmapSuccess;
event = EVENT_MMAP_SUCCESS_NEW;
} else if (mmap_ofs > 0) {
event = EVENT_MMAP_SUCCESS_PARTIAL;
} else {
DCHECK_EQ(MetaTable::kMmapFailure, mmap_ofs);
event = EVENT_MMAP_FAILED_NEW;
}
if (mmap_alt_status_) {
if (!SetMmapAltStatus(mmap_ofs)) {
RecordOneEvent(EVENT_MMAP_STATUS_FAILURE_UPDATE);
return 0;
}
} else {
if (!MetaTable::SetMmapStatus(this, mmap_ofs)) {
RecordOneEvent(EVENT_MMAP_META_FAILURE_UPDATE);
return 0;
}
}
RecordOneEvent(event);
}
}
if (mmap_ofs == MetaTable::kMmapFailure)
return 0;
if (mmap_ofs == MetaTable::kMmapSuccess)
return kMmapEverything;
return mmap_ofs;
}
void Connection::TrimMemory(bool aggressively) {
if (!db_)
return;
// TODO(shess): investigate using sqlite3_db_release_memory() when possible.
int original_cache_size;
{
Statement sql_get_original(GetUniqueStatement("PRAGMA cache_size"));
if (!sql_get_original.Step()) {
DLOG(WARNING) << "Could not get cache size " << GetErrorMessage();
return;
}
original_cache_size = sql_get_original.ColumnInt(0);
}
int shrink_cache_size = aggressively ? 1 : (original_cache_size / 2);
// Force sqlite to try to reduce page cache usage.
const std::string sql_shrink =
base::StringPrintf("PRAGMA cache_size=%d", shrink_cache_size);
if (!Execute(sql_shrink.c_str()))
DLOG(WARNING) << "Could not shrink cache size: " << GetErrorMessage();
// Restore cache size.
const std::string sql_restore =
base::StringPrintf("PRAGMA cache_size=%d", original_cache_size);
if (!Execute(sql_restore.c_str()))
DLOG(WARNING) << "Could not restore cache size: " << GetErrorMessage();
}
// Create an in-memory database with the existing database's page
// size, then backup that database over the existing database.
bool Connection::Raze() {
AssertIOAllowed();
if (!db_) {
DCHECK(poisoned_) << "Cannot raze null db";
return false;
}
if (transaction_nesting_ > 0) {
DLOG(DCHECK) << "Cannot raze within a transaction";
return false;
}
sql::Connection null_db;
if (!null_db.OpenInMemory()) {
DLOG(DCHECK) << "Unable to open in-memory database.";
return false;
}
if (page_size_) {
// Enforce SQLite restrictions on |page_size_|.
DCHECK(!(page_size_ & (page_size_ - 1)))
<< " page_size_ " << page_size_ << " is not a power of two.";
const int kSqliteMaxPageSize = 32768; // from sqliteLimit.h
DCHECK_LE(page_size_, kSqliteMaxPageSize);
const std::string sql =
base::StringPrintf("PRAGMA page_size=%d", page_size_);
if (!null_db.Execute(sql.c_str()))
return false;
}
#if defined(OS_ANDROID)
// Android compiles with SQLITE_DEFAULT_AUTOVACUUM. Unfortunately,
// in-memory databases do not respect this define.
// TODO(shess): Figure out a way to set this without using platform
// specific code. AFAICT from sqlite3.c, the only way to do it
// would be to create an actual filesystem database, which is
// unfortunate.
if (!null_db.Execute("PRAGMA auto_vacuum = 1"))
return false;
#endif
// The page size doesn't take effect until a database has pages, and
// at this point the null database has none. Changing the schema
// version will create the first page. This will not affect the
// schema version in the resulting database, as SQLite's backup
// implementation propagates the schema version from the original
// connection to the new version of the database, incremented by one
// so that other readers see the schema change and act accordingly.
if (!null_db.Execute("PRAGMA schema_version = 1"))
return false;
// SQLite tracks the expected number of database pages in the first
// page, and if it does not match the total retrieved from a
// filesystem call, treats the database as corrupt. This situation
// breaks almost all SQLite calls. "PRAGMA writable_schema" can be
// used to hint to SQLite to soldier on in that case, specifically
// for purposes of recovery. [See SQLITE_CORRUPT_BKPT case in
// sqlite3.c lockBtree().]
// TODO(shess): With this, "PRAGMA auto_vacuum" and "PRAGMA
// page_size" can be used to query such a database.
ScopedWritableSchema writable_schema(db_);
#if defined(OS_WIN)
// On Windows, truncate silently fails when applied to memory-mapped files.
// Disable memory-mapping so that the truncate succeeds. Note that other
// connections may have memory-mapped the file, so this may not entirely
// prevent the problem.
// [Source: <https://sqlite.org/mmap.html> plus experiments.]
ignore_result(Execute("PRAGMA mmap_size = 0"));
#endif
const char* kMain = "main";
int rc = BackupDatabase(null_db.db_, db_, kMain);
base::UmaHistogramSparse("Sqlite.RazeDatabase", rc);
// The destination database was locked.
if (rc == SQLITE_BUSY) {
return false;
}
// SQLITE_NOTADB can happen if page 1 of db_ exists, but is not
// formatted correctly. SQLITE_IOERR_SHORT_READ can happen if db_
// isn't even big enough for one page. Either way, reach in and
// truncate it before trying again.
// TODO(shess): Maybe it would be worthwhile to just truncate from
// the get-go?
if (rc == SQLITE_NOTADB || rc == SQLITE_IOERR_SHORT_READ) {
sqlite3_file* file = NULL;
rc = GetSqlite3File(db_, &file);
if (rc != SQLITE_OK) {
DLOG(DCHECK) << "Failure getting file handle.";
return false;
}
rc = file->pMethods->xTruncate(file, 0);
if (rc != SQLITE_OK) {
base::UmaHistogramSparse("Sqlite.RazeDatabaseTruncate", rc);
DLOG(DCHECK) << "Failed to truncate file.";
return false;
}
rc = BackupDatabase(null_db.db_, db_, kMain);
base::UmaHistogramSparse("Sqlite.RazeDatabase2", rc);
DCHECK_EQ(rc, SQLITE_DONE) << "Failed retrying Raze().";
}
// TODO(shess): Figure out which other cases can happen.
DCHECK_EQ(rc, SQLITE_DONE) << "Unable to copy entire null database.";
// The entire database should have been backed up.
return rc == SQLITE_DONE;
}
bool Connection::RazeAndClose() {
if (!db_) {
DCHECK(poisoned_) << "Cannot raze null db";
return false;
}
// Raze() cannot run in a transaction.
RollbackAllTransactions();
bool result = Raze();
CloseInternal(true);
// Mark the database so that future API calls fail appropriately,
// but don't DCHECK (because after calling this function they are
// expected to fail).
poisoned_ = true;
return result;
}
void Connection::Poison() {
if (!db_) {
DCHECK(poisoned_) << "Cannot poison null db";
return;
}
RollbackAllTransactions();
CloseInternal(true);
// Mark the database so that future API calls fail appropriately,
// but don't DCHECK (because after calling this function they are
// expected to fail).
poisoned_ = true;
}
// TODO(shess): To the extent possible, figure out the optimal
// ordering for these deletes which will prevent other connections
// from seeing odd behavior. For instance, it may be necessary to
// manually lock the main database file in a SQLite-compatible fashion
// (to prevent other processes from opening it), then delete the
// journal files, then delete the main database file. Another option
// might be to lock the main database file and poison the header with
// junk to prevent other processes from opening it successfully (like
// Gears "SQLite poison 3" trick).
//
// static
bool Connection::Delete(const base::FilePath& path) {
base::AssertBlockingAllowed();
base::FilePath journal_path(path.value() + FILE_PATH_LITERAL("-journal"));
base::FilePath wal_path(path.value() + FILE_PATH_LITERAL("-wal"));
std::string journal_str = AsUTF8ForSQL(journal_path);
std::string wal_str = AsUTF8ForSQL(wal_path);
std::string path_str = AsUTF8ForSQL(path);
// Make sure sqlite3_initialize() is called before anything else.
InitializeSqlite();
sqlite3_vfs* vfs = sqlite3_vfs_find(NULL);
CHECK(vfs);
CHECK(vfs->xDelete);
CHECK(vfs->xAccess);
// We only work with unix, win32 and mojo filesystems. If you're trying to
// use this code with any other VFS, you're not in a good place.
CHECK(strncmp(vfs->zName, "unix", 4) == 0 ||
strncmp(vfs->zName, "win32", 5) == 0 ||
strcmp(vfs->zName, "mojo") == 0);
vfs->xDelete(vfs, journal_str.c_str(), 0);
vfs->xDelete(vfs, wal_str.c_str(), 0);
vfs->xDelete(vfs, path_str.c_str(), 0);
int journal_exists = 0;
vfs->xAccess(vfs, journal_str.c_str(), SQLITE_ACCESS_EXISTS,
&journal_exists);
int wal_exists = 0;
vfs->xAccess(vfs, wal_str.c_str(), SQLITE_ACCESS_EXISTS,
&wal_exists);
int path_exists = 0;
vfs->xAccess(vfs, path_str.c_str(), SQLITE_ACCESS_EXISTS,
&path_exists);
return !journal_exists && !wal_exists && !path_exists;
}
bool Connection::BeginTransaction() {
if (needs_rollback_) {
DCHECK_GT(transaction_nesting_, 0);
// When we're going to rollback, fail on this begin and don't actually
// mark us as entering the nested transaction.
return false;
}
bool success = true;
if (!transaction_nesting_) {
needs_rollback_ = false;
Statement begin(GetCachedStatement(SQL_FROM_HERE, "BEGIN TRANSACTION"));
RecordOneEvent(EVENT_BEGIN);
if (!begin.Run())
return false;
}
transaction_nesting_++;
return success;
}
void Connection::RollbackTransaction() {
if (!transaction_nesting_) {
DCHECK(poisoned_) << "Rolling back a nonexistent transaction";
return;
}
transaction_nesting_--;
if (transaction_nesting_ > 0) {
// Mark the outermost transaction as needing rollback.
needs_rollback_ = true;
return;
}
DoRollback();
}
bool Connection::CommitTransaction() {
if (!transaction_nesting_) {
DCHECK(poisoned_) << "Committing a nonexistent transaction";
return false;
}
transaction_nesting_--;
if (transaction_nesting_ > 0) {
// Mark any nested transactions as failing after we've already got one.
return !needs_rollback_;
}
if (needs_rollback_) {
DoRollback();
return false;
}
Statement commit(GetCachedStatement(SQL_FROM_HERE, "COMMIT"));
// Collect the commit time manually, sql::Statement would register it as query
// time only.
const base::TimeTicks before = Now();
bool ret = commit.RunWithoutTimers();
const base::TimeDelta delta = Now() - before;
RecordCommitTime(delta);
RecordOneEvent(EVENT_COMMIT);
// Release dirty cache pages after the transaction closes.
ReleaseCacheMemoryIfNeeded(false);
return ret;
}
void Connection::RollbackAllTransactions() {
if (transaction_nesting_ > 0) {
transaction_nesting_ = 0;
DoRollback();
}
}
bool Connection::AttachDatabase(const base::FilePath& other_db_path,
const char* attachment_point) {
DCHECK(ValidAttachmentPoint(attachment_point));
Statement s(GetUniqueStatement("ATTACH DATABASE ? AS ?"));
#if OS_WIN
s.BindString16(0, other_db_path.value());
#else
s.BindString(0, other_db_path.value());
#endif
s.BindString(1, attachment_point);
return s.Run();
}
bool Connection::DetachDatabase(const char* attachment_point) {
DCHECK(ValidAttachmentPoint(attachment_point));
Statement s(GetUniqueStatement("DETACH DATABASE ?"));
s.BindString(0, attachment_point);
return s.Run();
}
// TODO(shess): Consider changing this to execute exactly one statement. If a
// caller wishes to execute multiple statements, that should be explicit, and
// perhaps tucked into an explicit transaction with rollback in case of error.
int Connection::ExecuteAndReturnErrorCode(const char* sql) {
AssertIOAllowed();
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return SQLITE_ERROR;
}
DCHECK(sql);
RecordOneEvent(EVENT_EXECUTE);
int rc = SQLITE_OK;
while ((rc == SQLITE_OK) && *sql) {
sqlite3_stmt *stmt = NULL;
const char *leftover_sql;
const base::TimeTicks before = Now();
rc = sqlite3_prepare_v2(db_, sql, -1, &stmt, &leftover_sql);
sql = leftover_sql;
// Stop if an error is encountered.
if (rc != SQLITE_OK)
break;
// This happens if |sql| originally only contained comments or whitespace.
// TODO(shess): Audit to see if this can become a DCHECK(). Having
// extraneous comments and whitespace in the SQL statements increases
// runtime cost and can easily be shifted out to the C++ layer.
if (!stmt)
continue;
// Save for use after statement is finalized.
const bool read_only = !!sqlite3_stmt_readonly(stmt);
RecordOneEvent(Connection::EVENT_STATEMENT_RUN);
while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
// TODO(shess): Audit to see if this can become a DCHECK. I think PRAGMA
// is the only legitimate case for this.
RecordOneEvent(Connection::EVENT_STATEMENT_ROWS);
}
// sqlite3_finalize() returns SQLITE_OK if the most recent sqlite3_step()
// returned SQLITE_DONE or SQLITE_ROW, otherwise the error code.
rc = sqlite3_finalize(stmt);
if (rc == SQLITE_OK)
RecordOneEvent(Connection::EVENT_STATEMENT_SUCCESS);
// sqlite3_exec() does this, presumably to avoid spinning the parser for
// trailing whitespace.
// TODO(shess): Audit to see if this can become a DCHECK.
while (base::IsAsciiWhitespace(*sql)) {
sql++;
}
const base::TimeDelta delta = Now() - before;
RecordTimeAndChanges(delta, read_only);
}
// Most calls to Execute() modify the database. The main exceptions would be
// calls such as CREATE TABLE IF NOT EXISTS which could modify the database
// but sometimes don't.
ReleaseCacheMemoryIfNeeded(true);
return rc;
}
bool Connection::Execute(const char* sql) {
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return false;
}
int error = ExecuteAndReturnErrorCode(sql);
if (error != SQLITE_OK)
error = OnSqliteError(error, NULL, sql);
// This needs to be a FATAL log because the error case of arriving here is
// that there's a malformed SQL statement. This can arise in development if
// a change alters the schema but not all queries adjust. This can happen
// in production if the schema is corrupted.
DCHECK_NE(error, SQLITE_ERROR)
<< "SQL Error in " << sql << ", " << GetErrorMessage();
return error == SQLITE_OK;
}
bool Connection::ExecuteWithTimeout(const char* sql, base::TimeDelta timeout) {
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return false;
}
ScopedBusyTimeout busy_timeout(db_);
busy_timeout.SetTimeout(timeout);
return Execute(sql);
}
bool Connection::HasCachedStatement(const StatementID& id) const {
return statement_cache_.find(id) != statement_cache_.end();
}
scoped_refptr<Connection::StatementRef> Connection::GetCachedStatement(
const StatementID& id,
const char* sql) {
CachedStatementMap::iterator i = statement_cache_.find(id);
if (i != statement_cache_.end()) {
// Statement is in the cache. It should still be active (we're the only
// one invalidating cached statements, and we'll remove it from the cache
// if we do that. Make sure we reset it before giving out the cached one in
// case it still has some stuff bound.
DCHECK(i->second->is_valid());
sqlite3_reset(i->second->stmt());
return i->second;
}
scoped_refptr<StatementRef> statement = GetUniqueStatement(sql);
if (statement->is_valid())
statement_cache_[id] = statement; // Only cache valid statements.
return statement;
}
scoped_refptr<Connection::StatementRef> Connection::GetUniqueStatement(
const char* sql) {
return GetStatementImpl(this, sql);
}
scoped_refptr<Connection::StatementRef> Connection::GetStatementImpl(
sql::Connection* tracking_db, const char* sql) const {
AssertIOAllowed();
DCHECK(sql);
DCHECK(!tracking_db || const_cast<Connection*>(tracking_db)==this);
// Return inactive statement.
if (!db_)
return new StatementRef(NULL, NULL, poisoned_);
sqlite3_stmt* stmt = NULL;
int rc = sqlite3_prepare_v2(db_, sql, -1, &stmt, NULL);
if (rc != SQLITE_OK) {
// This is evidence of a syntax error in the incoming SQL.
DCHECK_NE(rc, SQLITE_ERROR) << "SQL compile error " << GetErrorMessage();
// It could also be database corruption.
OnSqliteError(rc, NULL, sql);
return new StatementRef(NULL, NULL, false);
}
return new StatementRef(tracking_db, stmt, true);
}
scoped_refptr<Connection::StatementRef> Connection::GetUntrackedStatement(
const char* sql) const {
return GetStatementImpl(NULL, sql);
}
std::string Connection::GetSchema() const {
// The ORDER BY should not be necessary, but relying on organic
// order for something like this is questionable.
const char* kSql =
"SELECT type, name, tbl_name, sql "
"FROM sqlite_master ORDER BY 1, 2, 3, 4";
Statement statement(GetUntrackedStatement(kSql));
std::string schema;
while (statement.Step()) {
schema += statement.ColumnString(0);
schema += '|';
schema += statement.ColumnString(1);
schema += '|';
schema += statement.ColumnString(2);
schema += '|';
schema += statement.ColumnString(3);
schema += '\n';
}
return schema;
}
bool Connection::IsSQLValid(const char* sql) {
AssertIOAllowed();
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return false;
}
sqlite3_stmt* stmt = NULL;
if (sqlite3_prepare_v2(db_, sql, -1, &stmt, NULL) != SQLITE_OK)
return false;
sqlite3_finalize(stmt);
return true;
}
bool Connection::DoesIndexExist(const char* index_name) const {
return DoesSchemaItemExist(index_name, "index");
}
bool Connection::DoesTableExist(const char* table_name) const {
return DoesSchemaItemExist(table_name, "table");
}
bool Connection::DoesViewExist(const char* view_name) const {
return DoesSchemaItemExist(view_name, "view");
}
bool Connection::DoesSchemaItemExist(
const char* name, const char* type) const {
const char* kSql =
"SELECT name FROM sqlite_master WHERE type=? AND name=? COLLATE NOCASE";
Statement statement(GetUntrackedStatement(kSql));
// This can happen if the database is corrupt and the error is a test
// expectation.
if (!statement.is_valid())
return false;
statement.BindString(0, type);
statement.BindString(1, name);
return statement.Step(); // Table exists if any row was returned.
}
bool Connection::DoesColumnExist(const char* table_name,
const char* column_name) const {
std::string sql("PRAGMA TABLE_INFO(");
sql.append(table_name);
sql.append(")");
Statement statement(GetUntrackedStatement(sql.c_str()));
// This can happen if the database is corrupt and the error is a test
// expectation.
if (!statement.is_valid())
return false;
while (statement.Step()) {
if (base::EqualsCaseInsensitiveASCII(statement.ColumnString(1),
column_name))
return true;
}
return false;
}
int64_t Connection::GetLastInsertRowId() const {
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return 0;
}
return sqlite3_last_insert_rowid(db_);
}
int Connection::GetLastChangeCount() const {
if (!db_) {
DCHECK(poisoned_) << "Illegal use of connection without a db";
return 0;
}
return sqlite3_changes(db_);
}
int Connection::GetErrorCode() const {
if (!db_)
return SQLITE_ERROR;
return sqlite3_errcode(db_);
}
int Connection::GetLastErrno() const {
if (!db_)
return -1;
int err = 0;
if (SQLITE_OK != sqlite3_file_control(db_, NULL, SQLITE_LAST_ERRNO, &err))
return -2;
return err;
}
const char* Connection::GetErrorMessage() const {
if (!db_)
return "sql::Connection has no connection.";
return sqlite3_errmsg(db_);
}
bool Connection::OpenInternal(const std::string& file_name,
Connection::Retry retry_flag) {
AssertIOAllowed();
if (db_) {
DLOG(DCHECK) << "sql::Connection is already open.";
return false;
}
// Make sure sqlite3_initialize() is called before anything else.
InitializeSqlite();
// Setup the stats histograms immediately rather than allocating lazily.
// Connections which won't exercise all of these probably shouldn't exist.
if (!histogram_tag_.empty()) {
stats_histogram_ =
base::LinearHistogram::FactoryGet(
"Sqlite.Stats." + histogram_tag_,
1, EVENT_MAX_VALUE, EVENT_MAX_VALUE + 1,
base::HistogramBase::kUmaTargetedHistogramFlag);
// The timer setup matches UMA_HISTOGRAM_MEDIUM_TIMES(). 3 minutes is an
// unreasonable time for any single operation, so there is not much value to
// knowing if it was 3 minutes or 5 minutes. In reality at that point
// things are entirely busted.
commit_time_histogram_ =
GetMediumTimeHistogram("Sqlite.CommitTime." + histogram_tag_);
autocommit_time_histogram_ =
GetMediumTimeHistogram("Sqlite.AutoCommitTime." + histogram_tag_);
update_time_histogram_ =
GetMediumTimeHistogram("Sqlite.UpdateTime." + histogram_tag_);
query_time_histogram_ =
GetMediumTimeHistogram("Sqlite.QueryTime." + histogram_tag_);
}
// If |poisoned_| is set, it means an error handler called
// RazeAndClose(). Until regular Close() is called, the caller
// should be treating the database as open, but is_open() currently
// only considers the sqlite3 handle's state.
// TODO(shess): Revise is_open() to consider poisoned_, and review
// to see if any non-testing code even depends on it.
DCHECK(!poisoned_) << "sql::Connection is already open.";
poisoned_ = false;
// Custom memory-mapping VFS which reads pages using regular I/O on first hit.
sqlite3_vfs* vfs = VFSWrapper();
const char* vfs_name = (vfs ? vfs->zName : nullptr);
int err = sqlite3_open_v2(file_name.c_str(), &db_,
SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
vfs_name);
if (err != SQLITE_OK) {
// Extended error codes cannot be enabled until a handle is
// available, fetch manually.
err = sqlite3_extended_errcode(db_);
// Histogram failures specific to initial open for debugging
// purposes.
base::UmaHistogramSparse("Sqlite.OpenFailure", err);
OnSqliteError(err, NULL, "-- sqlite3_open()");
bool was_poisoned = poisoned_;
Close();
if (was_poisoned && retry_flag == RETRY_ON_POISON)
return OpenInternal(file_name, NO_RETRY);
return false;
}
// TODO(shess): OS_WIN support?
#if defined(OS_POSIX) && !defined(OS_FUCHSIA)
if (restrict_to_user_) {
DCHECK_NE(file_name, std::string(":memory"));
base::FilePath file_path(file_name);
int mode = 0;
// TODO(shess): Arguably, failure to retrieve and change
// permissions should be fatal if the file exists.
if (base::GetPosixFilePermissions(file_path, &mode)) {
mode &= base::FILE_PERMISSION_USER_MASK;
base::SetPosixFilePermissions(file_path, mode);
// SQLite sets the permissions on these files from the main
// database on create. Set them here in case they already exist
// at this point. Failure to set these permissions should not
// be fatal unless the file doesn't exist.
base::FilePath journal_path(file_name + FILE_PATH_LITERAL("-journal"));
base::FilePath wal_path(file_name + FILE_PATH_LITERAL("-wal"));
base::SetPosixFilePermissions(journal_path, mode);
base::SetPosixFilePermissions(wal_path, mode);
}
}
#endif // defined(OS_POSIX) && !defined(OS_FUCHSIA)
// SQLite uses a lookaside buffer to improve performance of small mallocs.
// Chromium already depends on small mallocs being efficient, so we disable
// this to avoid the extra memory overhead.
// This must be called immediatly after opening the database before any SQL
// statements are run.
sqlite3_db_config(db_, SQLITE_DBCONFIG_LOOKASIDE, NULL, 0, 0);
// Enable extended result codes to provide more color on I/O errors.
// Not having extended result codes is not a fatal problem, as
// Chromium code does not attempt to handle I/O errors anyhow. The
// current implementation always returns SQLITE_OK, the DCHECK is to
// quickly notify someone if SQLite changes.
err = sqlite3_extended_result_codes(db_, 1);
DCHECK_EQ(err, SQLITE_OK) << "Could not enable extended result codes";
// sqlite3_open() does not actually read the database file (unless a hot
// journal is found). Successfully executing this pragma on an existing
// database requires a valid header on page 1. ExecuteAndReturnErrorCode() to
// get the error code before error callback (potentially) overwrites.
// TODO(shess): For now, just probing to see what the lay of the
// land is. If it's mostly SQLITE_NOTADB, then the database should
// be razed.
err = ExecuteAndReturnErrorCode("PRAGMA auto_vacuum");
if (err != SQLITE_OK) {
base::UmaHistogramSparse("Sqlite.OpenProbeFailure", err);
OnSqliteError(err, nullptr, "PRAGMA auto_vacuum");
// Retry or bail out if the error handler poisoned the handle.
// TODO(shess): Move this handling to one place (see also sqlite3_open and
// secure_delete). Possibly a wrapper function?
if (poisoned_) {
Close();
if (retry_flag == RETRY_ON_POISON)
return OpenInternal(file_name, NO_RETRY);
return false;
}
}
#if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
// The version of SQLite shipped with iOS doesn't enable ICU, which includes
// REGEXP support. Add it in dynamically.
err = sqlite3IcuInit(db_);
DCHECK_EQ(err, SQLITE_OK) << "Could not enable ICU support";
#endif // OS_IOS && USE_SYSTEM_SQLITE
// If indicated, lock up the database before doing anything else, so
// that the following code doesn't have to deal with locking.
// TODO(shess): This code is brittle. Find the cases where code
// doesn't request |exclusive_locking_| and audit that it does the
// right thing with SQLITE_BUSY, and that it doesn't make
// assumptions about who might change things in the database.
// http://crbug.com/56559
if (exclusive_locking_) {
// TODO(shess): This should probably be a failure. Code which
// requests exclusive locking but doesn't get it is almost certain
// to be ill-tested.
ignore_result(Execute("PRAGMA locking_mode=EXCLUSIVE"));
}
// http://www.sqlite.org/pragma.html#pragma_journal_mode
// DELETE (default) - delete -journal file to commit.
// TRUNCATE - truncate -journal file to commit.
// PERSIST - zero out header of -journal file to commit.
// TRUNCATE should be faster than DELETE because it won't need directory
// changes for each transaction. PERSIST may break the spirit of using
// secure_delete.
ignore_result(Execute("PRAGMA journal_mode = TRUNCATE"));
const base::TimeDelta kBusyTimeout =
base::TimeDelta::FromSeconds(kBusyTimeoutSeconds);
if (page_size_ != 0) {
// Enforce SQLite restrictions on |page_size_|.
DCHECK(!(page_size_ & (page_size_ - 1)))
<< " page_size_ " << page_size_ << " is not a power of two.";
const int kSqliteMaxPageSize = 32768; // from sqliteLimit.h
DCHECK_LE(page_size_, kSqliteMaxPageSize);
const std::string sql =
base::StringPrintf("PRAGMA page_size=%d", page_size_);
ignore_result(ExecuteWithTimeout(sql.c_str(), kBusyTimeout));
}
if (cache_size_ != 0) {
const std::string sql =
base::StringPrintf("PRAGMA cache_size=%d", cache_size_);
ignore_result(ExecuteWithTimeout(sql.c_str(), kBusyTimeout));
}
if (!ExecuteWithTimeout("PRAGMA secure_delete=ON", kBusyTimeout)) {
bool was_poisoned = poisoned_;
Close();
if (was_poisoned && retry_flag == RETRY_ON_POISON)
return OpenInternal(file_name, NO_RETRY);
return false;
}
// Set a reasonable chunk size for larger files. This reduces churn from
// remapping memory on size changes. It also reduces filesystem
// fragmentation.
// TODO(shess): It may make sense to have this be hinted by the client.
// Database sizes seem to be bimodal, some clients have consistently small
// databases (<20k) while other clients have a broad distribution of sizes
// (hundreds of kilobytes to many megabytes).
sqlite3_file* file = NULL;
sqlite3_int64 db_size = 0;
int rc = GetSqlite3FileAndSize(db_, &file, &db_size);
if (rc == SQLITE_OK && db_size > 16 * 1024) {
int chunk_size = 4 * 1024;
if (db_size > 128 * 1024)
chunk_size = 32 * 1024;
sqlite3_file_control(db_, NULL, SQLITE_FCNTL_CHUNK_SIZE, &chunk_size);
}
// Enable memory-mapped access. The explicit-disable case is because SQLite
// can be built to default-enable mmap. GetAppropriateMmapSize() calculates a
// safe range to memory-map based on past regular I/O. This value will be
// capped by SQLITE_MAX_MMAP_SIZE, which could be different between 32-bit and
// 64-bit platforms.
size_t mmap_size = mmap_disabled_ ? 0 : GetAppropriateMmapSize();
std::string mmap_sql =
base::StringPrintf("PRAGMA mmap_size = %" PRIuS, mmap_size);
ignore_result(Execute(mmap_sql.c_str()));
// Determine if memory-mapping has actually been enabled. The Execute() above
// can succeed without changing the amount mapped.
mmap_enabled_ = false;
{
Statement s(GetUniqueStatement("PRAGMA mmap_size"));
if (s.Step() && s.ColumnInt64(0) > 0)
mmap_enabled_ = true;
}
DCHECK(!memory_dump_provider_);
memory_dump_provider_.reset(
new ConnectionMemoryDumpProvider(db_, histogram_tag_));
base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
memory_dump_provider_.get(), "sql::Connection", nullptr);
return true;
}
void Connection::DoRollback() {
Statement rollback(GetCachedStatement(SQL_FROM_HERE, "ROLLBACK"));
// Collect the rollback time manually, sql::Statement would register it as
// query time only.
const base::TimeTicks before = Now();
rollback.RunWithoutTimers();
const base::TimeDelta delta = Now() - before;
RecordUpdateTime(delta);
RecordOneEvent(EVENT_ROLLBACK);
// The cache may have been accumulating dirty pages for commit. Note that in
// some cases sql::Transaction can fire rollback after a database is closed.
if (is_open())
ReleaseCacheMemoryIfNeeded(false);
needs_rollback_ = false;
}
void Connection::StatementRefCreated(StatementRef* ref) {
DCHECK(open_statements_.find(ref) == open_statements_.end());
open_statements_.insert(ref);
}
void Connection::StatementRefDeleted(StatementRef* ref) {
StatementRefSet::iterator i = open_statements_.find(ref);
if (i == open_statements_.end())
DLOG(DCHECK) << "Could not find statement";
else
open_statements_.erase(i);
}
void Connection::set_histogram_tag(const std::string& tag) {
DCHECK(!is_open());
histogram_tag_ = tag;
}
void Connection::AddTaggedHistogram(const std::string& name,
size_t sample) const {
if (histogram_tag_.empty())
return;
// TODO(shess): The histogram macros create a bit of static storage
// for caching the histogram object. This code shouldn't execute
// often enough for such caching to be crucial. If it becomes an
// issue, the object could be cached alongside histogram_prefix_.
std::string full_histogram_name = name + "." + histogram_tag_;
base::HistogramBase* histogram =
base::SparseHistogram::FactoryGet(
full_histogram_name,
base::HistogramBase::kUmaTargetedHistogramFlag);
if (histogram)
histogram->Add(sample);
}
int Connection::OnSqliteError(
int err, sql::Statement *stmt, const char* sql) const {
base::UmaHistogramSparse("Sqlite.Error", err);
AddTaggedHistogram("Sqlite.Error", err);
// Always log the error.
if (!sql && stmt)
sql = stmt->GetSQLStatement();
if (!sql)
sql = "-- unknown";
std::string id = histogram_tag_;
if (id.empty())
id = DbPath().BaseName().AsUTF8Unsafe();
LOG(ERROR) << id << " sqlite error " << err
<< ", errno " << GetLastErrno()
<< ": " << GetErrorMessage()
<< ", sql: " << sql;
if (!error_callback_.is_null()) {
// Fire from a copy of the callback in case of reentry into
// re/set_error_callback().
// TODO(shess): <http://crbug.com/254584>
ErrorCallback(error_callback_).Run(err, stmt);
return err;
}
// The default handling is to assert on debug and to ignore on release.
if (!IsExpectedSqliteError(err))
DLOG(DCHECK) << GetErrorMessage();
return err;
}
bool Connection::FullIntegrityCheck(std::vector<std::string>* messages) {
return IntegrityCheckHelper("PRAGMA integrity_check", messages);
}
bool Connection::QuickIntegrityCheck() {
std::vector<std::string> messages;
if (!IntegrityCheckHelper("PRAGMA quick_check", &messages))
return false;
return messages.size() == 1 && messages[0] == "ok";
}
std::string Connection::GetDiagnosticInfo(int extended_error,
Statement* statement) {
// Prevent reentrant calls to the error callback.
ErrorCallback original_callback = std::move(error_callback_);
reset_error_callback();
// Trim extended error codes.
const int error = (extended_error & 0xFF);
// CollectCorruptionInfo() is implemented in terms of sql::Connection,
// TODO(shess): Rewrite IntegrityCheckHelper() in terms of raw SQLite.
std::string result = (error == SQLITE_CORRUPT)
? CollectCorruptionInfo()
: CollectErrorInfo(extended_error, statement);
// The following queries must be executed after CollectErrorInfo() above, so
// if they result in their own errors, they don't interfere with
// CollectErrorInfo().
const bool has_valid_header =
(ExecuteAndReturnErrorCode("PRAGMA auto_vacuum") == SQLITE_OK);
const bool select_sqlite_master_result =
(ExecuteAndReturnErrorCode("SELECT COUNT(*) FROM sqlite_master") ==
SQLITE_OK);
// Restore the original error callback.
error_callback_ = std::move(original_callback);
base::StringAppendF(&result, "Has valid header: %s\n",
(has_valid_header ? "Yes" : "No"));
base::StringAppendF(&result, "Has valid schema: %s\n",
(select_sqlite_master_result ? "Yes" : "No"));
return result;
}
// TODO(shess): Allow specifying maximum results (default 100 lines).
bool Connection::IntegrityCheckHelper(
const char* pragma_sql,
std::vector<std::string>* messages) {
messages->clear();
// This has the side effect of setting SQLITE_RecoveryMode, which
// allows SQLite to process through certain cases of corruption.
// Failing to set this pragma probably means that the database is
// beyond recovery.
const char kWritableSchema[] = "PRAGMA writable_schema = ON";
if (!Execute(kWritableSchema))
return false;
bool ret = false;
{
sql::Statement stmt(GetUniqueStatement(pragma_sql));
// The pragma appears to return all results (up to 100 by default)
// as a single string. This doesn't appear to be an API contract,
// it could return separate lines, so loop _and_ split.
while (stmt.Step()) {
std::string result(stmt.ColumnString(0));
*messages = base::SplitString(result, "\n", base::TRIM_WHITESPACE,
base::SPLIT_WANT_ALL);
}
ret = stmt.Succeeded();
}
// Best effort to put things back as they were before.
const char kNoWritableSchema[] = "PRAGMA writable_schema = OFF";
ignore_result(Execute(kNoWritableSchema));
return ret;
}
bool Connection::ReportMemoryUsage(base::trace_event::ProcessMemoryDump* pmd,
const std::string& dump_name) {
return memory_dump_provider_ &&
memory_dump_provider_->ReportMemoryUsage(pmd, dump_name);
}
base::TimeTicks TimeSource::Now() {
return base::TimeTicks::Now();
}
} // namespace sql