sql: Simplify the VFS wrapper.
All of SQLite's VFS implementations used by Chrome implement the V3 API.
This CL removes support for older VFS APIs from the VFS wrappers, and
removes the wrapping code for VFS methods that should never be used in
Chrome.
Change-Id: I0261817211d4daf2579c5d4caa5bd7995508169a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1562088
Reviewed-by: Chris Mumford <[email protected]>
Commit-Queue: Victor Costan <[email protected]>
Cr-Commit-Position: refs/heads/master@{#650057}diff --git a/sql/vfs_wrapper.cc b/sql/vfs_wrapper.cc
index 5087a2e..c3c2b9a 100644
--- a/sql/vfs_wrapper.cc
+++ b/sql/vfs_wrapper.cc
@@ -340,26 +340,6 @@
wrapped_vfs, relative_path, buf_size, absolute_path);
}
-void* DlOpen(sqlite3_vfs* vfs, const char* filename) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xDlOpen(wrapped_vfs, filename);
-}
-
-void DlError(sqlite3_vfs* vfs, int buf_size, char* error_buffer) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- wrapped_vfs->xDlError(wrapped_vfs, buf_size, error_buffer);
-}
-
-void(*DlSym(sqlite3_vfs* vfs, void* handle, const char* sym))(void) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xDlSym(wrapped_vfs, handle, sym);
-}
-
-void DlClose(sqlite3_vfs* vfs, void* handle) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- wrapped_vfs->xDlClose(wrapped_vfs, handle);
-}
-
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);
@@ -370,11 +350,6 @@
return wrapped_vfs->xSleep(wrapped_vfs, microseconds);
}
-int CurrentTime(sqlite3_vfs* vfs, double* now) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xCurrentTime(wrapped_vfs, now);
-}
-
int GetLastError(sqlite3_vfs* vfs, int e, char* s) {
sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
return wrapped_vfs->xGetLastError(wrapped_vfs, e, s);
@@ -385,22 +360,6 @@
return wrapped_vfs->xCurrentTimeInt64(wrapped_vfs, now);
}
-int SetSystemCall(sqlite3_vfs* vfs, const char* name,
- sqlite3_syscall_ptr func) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xSetSystemCall(wrapped_vfs, name, func);
-}
-
-sqlite3_syscall_ptr GetSystemCall(sqlite3_vfs* vfs, const char* name) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xGetSystemCall(wrapped_vfs, name);
-}
-
-const char* NextSystemCall(sqlite3_vfs* vfs, const char* name) {
- sqlite3_vfs* wrapped_vfs = GetWrappedVfs(vfs);
- return wrapped_vfs->xNextSystemCall(wrapped_vfs, name);
-}
-
} // namespace
sqlite3_vfs* VFSWrapper() {
@@ -435,13 +394,18 @@
// VFS implementations should always work with a SQLite that only knows about
// earlier versions.
- wrapper_vfs->iVersion = std::min(wrapped_vfs->iVersion, 3);
+ 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;
+ wrapper_vfs->pNext = nullptr; // Field used by SQLite.
wrapper_vfs->zName = kVFSName;
// Keep a reference to the wrapped vfs for use in methods.
@@ -452,26 +416,39 @@
wrapper_vfs->xDelete = &Delete;
wrapper_vfs->xAccess = &Access;
wrapper_vfs->xFullPathname = &FullPathname;
- wrapper_vfs->xDlOpen = &DlOpen;
- wrapper_vfs->xDlError = &DlError;
- wrapper_vfs->xDlSym = &DlSym;
- wrapper_vfs->xDlClose = &DlClose;
+
+ // 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.
- wrapper_vfs->xCurrentTime =
- (wrapped_vfs->xCurrentTime ? &CurrentTime : nullptr);
+
+ // |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_vfs.
- DCHECK(wrapped_vfs->xCurrentTimeInt64);
+
+ // 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_vfs.
- DCHECK(wrapped_vfs->xSetSystemCall);
- wrapper_vfs->xSetSystemCall = &SetSystemCall;
- DCHECK(wrapped_vfs->xGetSystemCall);
- wrapper_vfs->xGetSystemCall = &GetSystemCall;
- DCHECK(wrapped_vfs->xNextSystemCall);
- wrapper_vfs->xNextSystemCall = &NextSystemCall;
+
+ // 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)) {
