Remove GLV unlocking at all functions which process data modifiable in a second thread

This removes possible VM crashs when data to be sent is modified/cleared in a second thread.
It works by keeping the GVL lock for libpq functions that don't immediately process all the data and don't make a copy of it.
These are the `PQsend*`, `PQexec*` and some related functions.

Since pg-1.3 all the blocking functions or states are avoided by using the non-blocking API of libpq.
Therefore holding the GVL somewhat longer shouldn't matter that much.

Having some libpq function with and without unlocked GVL, results in `rb_thread_call_with_gvl()` sometimes needed and sometimes not to process callbacks.
Therefore `ruby_thread_has_gvl_p()` is used to check if it's needed on ruby<4.0.
In ruby-4.0+ `rb_thread_call_with_gvl()` doesn't care about whether GVL is already locked or not, so that it can be called in both cases.

Fixes #721

Author: larskanis

ext/gvl_wrappers.h

@@ -15,12 +15,17 @@
 #ifndef __gvl_wrappers_h
 #define __gvl_wrappers_h
 
+#include <ruby/version.h>
 #include <ruby/thread.h>
 
 #ifdef RUBY_EXTCONF_H
 #	include RUBY_EXTCONF_H
 #endif
 
+#if RUBY_API_VERSION_MAJOR < 4
+extern int ruby_thread_has_gvl_p(void);
+#endif
+
 #ifndef LIBPQ_HAS_CHUNK_MODE
 typedef struct pg_cancel_conn PGcancelConn;
 #endif
@@ -83,20 +88,35 @@ typedef struct pg_cancel_conn PGcancelConn;
 	}
 
 #ifdef ENABLE_GVL_UNLOCK
-#define DEFINE_GVLCB_STUB(name, when_non_void, rettype, lastparamtype, lastparamname) \
-	rettype gvl_##name(FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST3) lastparamtype lastparamname){ \
-		struct gvl_wrapper_##name##_params params = { \
-			{FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST1) lastparamname}, when_non_void((rettype)0) \
-		}; \
-		rb_thread_call_with_gvl(gvl_##name##_skeleton, &params); \
-		when_non_void( return params.retval; ) \
-	}
+	#if RUBY_API_VERSION_MAJOR >= 4 || defined(TRUFFLERUBY)
+		#define DEFINE_GVLCB_STUB(name, when_non_void, rettype, lastparamtype, lastparamname) \
+			rettype gvl_##name(FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST3) lastparamtype lastparamname){ \
+				struct gvl_wrapper_##name##_params params = { \
+					{FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST1) lastparamname}, when_non_void((rettype)0) \
+				}; \
+				rb_thread_call_with_gvl(gvl_##name##_skeleton, &params); \
+				when_non_void( return params.retval; ) \
+			}
+	#else
+		#define DEFINE_GVLCB_STUB(name, when_non_void, rettype, lastparamtype, lastparamname) \
+			rettype gvl_##name(FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST3) lastparamtype lastparamname){ \
+				struct gvl_wrapper_##name##_params params = { \
+					{FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST1) lastparamname}, when_non_void((rettype)0) \
+				}; \
+				if (ruby_thread_has_gvl_p()) { \
+					gvl_##name##_skeleton(&params); \
+				} else { \
+					rb_thread_call_with_gvl(gvl_##name##_skeleton, &params); \
+				} \
+				when_non_void( return params.retval; ) \
+			}
+	#endif
 #else
-#define DEFINE_GVLCB_STUB(name, when_non_void, rettype, lastparamtype, lastparamname) \
-	rettype gvl_##name(FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST3) lastparamtype lastparamname){ \
-		when_non_void( return ) \
-			name( FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST1) lastparamname ); \
-	}
+	#define DEFINE_GVLCB_STUB(name, when_non_void, rettype, lastparamtype, lastparamname) \
+		rettype gvl_##name(FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST3) lastparamtype lastparamname){ \
+			when_non_void( return ) \
+				name( FOR_EACH_PARAM_OF_##name(DEFINE_PARAM_LIST1) lastparamname ); \
+		}
 #endif
 
 #define GVL_TYPE_VOID(string)
@@ -121,50 +141,8 @@ typedef struct pg_cancel_conn PGcancelConn;
 
 #define FOR_EACH_PARAM_OF_PQping(param)
 
-#define FOR_EACH_PARAM_OF_PQexec(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQexecParams(param) \
-	param(PGconn *, conn) \
-	param(const char *, command) \
-	param(int, nParams) \
-	param(const Oid *, paramTypes) \
-	param(const char * const *, paramValues) \
-	param(const int *, paramLengths) \
-	param(const int *, paramFormats)
-
-#define FOR_EACH_PARAM_OF_PQexecPrepared(param) \
-	param(PGconn *, conn) \
-	param(const char *, stmtName) \
-	param(int, nParams) \
-	param(const char * const *, paramValues) \
-	param(const int *, paramLengths) \
-	param(const int *, paramFormats)
-
-#define FOR_EACH_PARAM_OF_PQprepare(param) \
-	param(PGconn *, conn) \
-	param(const char *, stmtName) \
-	param(const char *, query) \
-	param(int, nParams)
-
-#define FOR_EACH_PARAM_OF_PQdescribePrepared(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQdescribePortal(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQclosePrepared(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQclosePortal(param) \
-	param(PGconn *, conn)
-
 #define FOR_EACH_PARAM_OF_PQgetResult(param)
 
-#define FOR_EACH_PARAM_OF_PQputCopyData(param) \
-	param(PGconn *, conn) \
-	param(const char *, buffer)
-
 #define FOR_EACH_PARAM_OF_PQputCopyEnd(param) \
 	param(PGconn *, conn)
 
@@ -174,48 +152,8 @@ typedef struct pg_cancel_conn PGcancelConn;
 
 #define FOR_EACH_PARAM_OF_PQnotifies(param)
 
-#define FOR_EACH_PARAM_OF_PQsendQuery(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQsendQueryParams(param) \
-	param(PGconn *, conn) \
-	param(const char *, command) \
-	param(int, nParams) \
-	param(const Oid *, paramTypes) \
-	param(const char *const *, paramValues) \
-	param(const int *, paramLengths) \
-	param(const int *, paramFormats)
-
-#define FOR_EACH_PARAM_OF_PQsendPrepare(param) \
-	param(PGconn *, conn) \
-	param(const char *, stmtName) \
-	param(const char *, query) \
-	param(int, nParams)
-
-#define FOR_EACH_PARAM_OF_PQsendQueryPrepared(param) \
-	param(PGconn *, conn) \
-	param(const char *, stmtName) \
-	param(int, nParams) \
-	param(const char *const *, paramValues) \
-	param(const int *, paramLengths) \
-	param(const int *, paramFormats)
-
-#define FOR_EACH_PARAM_OF_PQsendDescribePrepared(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQsendDescribePortal(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQsendClosePrepared(param) \
-	param(PGconn *, conn)
-
-#define FOR_EACH_PARAM_OF_PQsendClosePortal(param) \
-	param(PGconn *, conn)
-
 #define FOR_EACH_PARAM_OF_PQpipelineSync(param)
 
-#define FOR_EACH_PARAM_OF_PQsendPipelineSync(param)
-
 #define FOR_EACH_PARAM_OF_PQsetClientEncoding(param) \
 	param(PGconn *, conn)
 
@@ -225,11 +163,6 @@ typedef struct pg_cancel_conn PGcancelConn;
 #define FOR_EACH_PARAM_OF_PQcancelStart(param)
 #define FOR_EACH_PARAM_OF_PQcancelPoll(param)
 
-#define FOR_EACH_PARAM_OF_PQencryptPasswordConn(param) \
-	param(PGconn *, conn) \
-	param(const char *, passwd) \
-	param(const char *, user)
-
 #define FOR_EACH_PARAM_OF_PQcancel(param) \
 	param(PGcancel *, cancel) \
 	param(char *, errbuf)
@@ -243,35 +176,16 @@ typedef struct pg_cancel_conn PGcancelConn;
 	function(PQresetStart, GVL_TYPE_NONVOID, int, PGconn *, conn) \
 	function(PQresetPoll, GVL_TYPE_NONVOID, PostgresPollingStatusType, PGconn *, conn) \
 	function(PQping, GVL_TYPE_NONVOID, PGPing, const char *, conninfo) \
-	function(PQexec, GVL_TYPE_NONVOID, PGresult *, const char *, command) \
-	function(PQexecParams, GVL_TYPE_NONVOID, PGresult *, int, resultFormat) \
-	function(PQexecPrepared, GVL_TYPE_NONVOID, PGresult *, int, resultFormat) \
-	function(PQprepare, GVL_TYPE_NONVOID, PGresult *, const Oid *, paramTypes) \
-	function(PQdescribePrepared, GVL_TYPE_NONVOID, PGresult *, const char *, stmtName) \
-	function(PQdescribePortal, GVL_TYPE_NONVOID, PGresult *, const char *, portalName) \
-	function(PQclosePrepared, GVL_TYPE_NONVOID, PGresult *, const char *, stmtName) \
-	function(PQclosePortal, GVL_TYPE_NONVOID, PGresult *, const char *, portalName) \
 	function(PQgetResult, GVL_TYPE_NONVOID, PGresult *, PGconn *, conn) \
-	function(PQputCopyData, GVL_TYPE_NONVOID, int, int, nbytes) \
 	function(PQputCopyEnd, GVL_TYPE_NONVOID, int, const char *, errormsg) \
 	function(PQgetCopyData, GVL_TYPE_NONVOID, int, int, async) \
 	function(PQnotifies, GVL_TYPE_NONVOID, PGnotify *, PGconn *, conn) \
-	function(PQsendQuery, GVL_TYPE_NONVOID, int, const char *, query) \
-	function(PQsendQueryParams, GVL_TYPE_NONVOID, int, int, resultFormat) \
-	function(PQsendPrepare, GVL_TYPE_NONVOID, int, const Oid *, paramTypes) \
-	function(PQsendQueryPrepared, GVL_TYPE_NONVOID, int, int, resultFormat) \
-	function(PQsendDescribePrepared, GVL_TYPE_NONVOID, int, const char *, stmt) \
-	function(PQsendDescribePortal, GVL_TYPE_NONVOID, int, const char *, portal) \
-	function(PQsendClosePrepared, GVL_TYPE_NONVOID, int, const char *, stmt) \
-	function(PQsendClosePortal, GVL_TYPE_NONVOID, int, const char *, portal) \
 	function(PQpipelineSync, GVL_TYPE_NONVOID, int, PGconn *, conn) \
-	function(PQsendPipelineSync, GVL_TYPE_NONVOID, int, PGconn *, conn) \
 	function(PQsetClientEncoding, GVL_TYPE_NONVOID, int, const char *, encoding) \
 	function(PQisBusy, GVL_TYPE_NONVOID, int, PGconn *, conn) \
 	function(PQcancelBlocking, GVL_TYPE_NONVOID, int, PGcancelConn *, conn) \
 	function(PQcancelStart, GVL_TYPE_NONVOID, int, PGcancelConn *, conn) \
 	function(PQcancelPoll, GVL_TYPE_NONVOID, PostgresPollingStatusType, PGcancelConn *, conn) \
-	function(PQencryptPasswordConn, GVL_TYPE_NONVOID, char *, const char *, algorithm) \
 	function(PQcancel, GVL_TYPE_NONVOID, int, int, errbufsize);
 
 FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_STUB_DECL );

ext/pg.h

@@ -82,6 +82,8 @@ typedef long suseconds_t;
 
 #define pg_gc_location(x) x = rb_gc_location(x)
 
+extern int ruby_native_thread_p(void);
+
 /* For compatibility with ruby < 3.0 */
 #ifndef RUBY_TYPED_FROZEN_SHAREABLE
 #define PG_RUBY_TYPED_FROZEN_SHAREABLE 0