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diff --git a/src/include/libpq/libpq-be-fe-helpers.h b/src/include/libpq/libpq-be-fe-helpers.h
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+/*-------------------------------------------------------------------------
+ *
+ * libpq-be-fe-helpers.h
+ *	  Helper functions for using libpq in extensions
+ *
+ * Code built directly into the backend is not allowed to link to libpq
+ * directly. Extension code is allowed to use libpq however. However, libpq
+ * used in extensions has to be careful to block inside libpq, otherwise
+ * interrupts will not be processed, leading to issues like unresolvable
+ * deadlocks. Backend code also needs to take care to acquire/release an
+ * external fd for the connection, otherwise fd.c's accounting of fd's is
+ * broken.
+ *
+ * This file provides helper functions to make it easier to comply with these
+ * rules. It is a header only library as it needs to be linked into each
+ * extension using libpq, and it seems too small to be worth adding a
+ * dedicated static library for.
+ *
+ * TODO: For historical reasons the connections established here are not put
+ * into non-blocking mode. That can lead to blocking even when only the async
+ * libpq functions are used. This should be fixed.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/libpq/libpq-be-fe-helpers.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef LIBPQ_BE_FE_HELPERS_H
+#define LIBPQ_BE_FE_HELPERS_H
+
+/*
+ * Despite the name, BUILDING_DLL is set only when building code directly part
+ * of the backend. Which also is where libpq isn't allowed to be
+ * used. Obviously this doesn't protect against libpq-fe.h getting included
+ * otherwise, but perhaps still protects against a few mistakes...
+ */
+#ifdef BUILDING_DLL
+#error "libpq may not be used code directly built into the backend"
+#endif
+
+#include "libpq-fe.h"
+#include "miscadmin.h"
+#include "storage/fd.h"
+#include "storage/latch.h"
+#include "utils/wait_event.h"
+
+
+static inline void libpqsrv_connect_prepare(void);
+static inline void libpqsrv_connect_internal(PGconn *conn, uint32 wait_event_info);
+
+
+/*
+ * PQconnectdb() wrapper that reserves a file descriptor and processes
+ * interrupts during connection establishment.
+ *
+ * Throws an error if AcquireExternalFD() fails, but does not throw if
+ * connection establishment itself fails. Callers need to use PQstatus() to
+ * check if connection establishment succeeded.
+ */
+static inline PGconn *
+libpqsrv_connect(const char *conninfo, uint32 wait_event_info)
+{
+	PGconn	   *conn = NULL;
+
+	libpqsrv_connect_prepare();
+
+	conn = PQconnectStart(conninfo);
+
+	libpqsrv_connect_internal(conn, wait_event_info);
+
+	return conn;
+}
+
+/*
+ * Like libpqsrv_connect(), except that this is a wrapper for
+ * PQconnectdbParams().
+  */
+static inline PGconn *
+libpqsrv_connect_params(const char *const *keywords,
+						const char *const *values,
+						int expand_dbname,
+						uint32 wait_event_info)
+{
+	PGconn	   *conn = NULL;
+
+	libpqsrv_connect_prepare();
+
+	conn = PQconnectStartParams(keywords, values, expand_dbname);
+
+	libpqsrv_connect_internal(conn, wait_event_info);
+
+	return conn;
+}
+
+/*
+ * PQfinish() wrapper that additionally releases the reserved file descriptor.
+ *
+ * It is allowed to call this with a NULL pgconn iff NULL was returned by
+ * libpqsrv_connect*.
+ */
+static inline void
+libpqsrv_disconnect(PGconn *conn)
+{
+	/*
+	 * If no connection was established, we haven't reserved an FD for it (or
+	 * already released it). This rule makes it easier to write PG_CATCH()
+	 * handlers for this facility's users.
+	 *
+	 * See also libpqsrv_connect_internal().
+	 */
+	if (conn == NULL)
+		return;
+
+	ReleaseExternalFD();
+	PQfinish(conn);
+}
+
+
+/* internal helper functions follow */
+
+
+/*
+ * Helper function for all connection establishment functions.
+ */
+static inline void
+libpqsrv_connect_prepare(void)
+{
+	/*
+	 * We must obey fd.c's limit on non-virtual file descriptors.  Assume that
+	 * a PGconn represents one long-lived FD.  (Doing this here also ensures
+	 * that VFDs are closed if needed to make room.)
+	 */
+	if (!AcquireExternalFD())
+	{
+#ifndef WIN32					/* can't write #if within ereport() macro */
+		ereport(ERROR,
+				(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
+				 errmsg("could not establish connection"),
+				 errdetail("There are too many open files on the local server."),
+				 errhint("Raise the server's max_files_per_process and/or \"ulimit -n\" limits.")));
+#else
+		ereport(ERROR,
+				(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
+				 errmsg("could not establish connection"),
+				 errdetail("There are too many open files on the local server."),
+				 errhint("Raise the server's max_files_per_process setting.")));
+#endif
+	}
+}
+
+/*
+ * Helper function for all connection establishment functions.
+ */
+static inline void
+libpqsrv_connect_internal(PGconn *conn, uint32 wait_event_info)
+{
+	/*
+	 * With conn == NULL libpqsrv_disconnect() wouldn't release the FD. So do
+	 * that here.
+	 */
+	if (conn == NULL)
+	{
+		ReleaseExternalFD();
+		return;
+	}
+
+	/*
+	 * Can't wait without a socket. Note that we don't want to close the libpq
+	 * connection yet, so callers can emit a useful error.
+	 */
+	if (PQstatus(conn) == CONNECTION_BAD)
+		return;
+
+	/*
+	 * WaitLatchOrSocket() can conceivably fail, handle that case here instead
+	 * of requiring all callers to do so.
+	 */
+	PG_TRY();
+	{
+		PostgresPollingStatusType status;
+
+		/*
+		 * Poll connection until we have OK or FAILED status.
+		 *
+		 * Per spec for PQconnectPoll, first wait till socket is write-ready.
+		 */
+		status = PGRES_POLLING_WRITING;
+		while (status != PGRES_POLLING_OK && status != PGRES_POLLING_FAILED)
+		{
+			int			io_flag;
+			int			rc;
+
+			if (status == PGRES_POLLING_READING)
+				io_flag = WL_SOCKET_READABLE;
+#ifdef WIN32
+
+			/*
+			 * Windows needs a different test while waiting for
+			 * connection-made
+			 */
+			else if (PQstatus(conn) == CONNECTION_STARTED)
+				io_flag = WL_SOCKET_CONNECTED;
+#endif
+			else
+				io_flag = WL_SOCKET_WRITEABLE;
+
+			rc = WaitLatchOrSocket(MyLatch,
+								   WL_EXIT_ON_PM_DEATH | WL_LATCH_SET | io_flag,
+								   PQsocket(conn),
+								   0,
+								   wait_event_info);
+
+			/* Interrupted? */
+			if (rc & WL_LATCH_SET)
+			{
+				ResetLatch(MyLatch);
+				CHECK_FOR_INTERRUPTS();
+			}
+
+			/* If socket is ready, advance the libpq state machine */
+			if (rc & io_flag)
+				status = PQconnectPoll(conn);
+		}
+	}
+	PG_CATCH();
+	{
+		/*
+		 * If an error is thrown here, the callers won't call
+		 * libpqsrv_disconnect() with a conn, so release resources
+		 * immediately.
+		 */
+		ReleaseExternalFD();
+		PQfinish(conn);
+
+		PG_RE_THROW();
+	}
+	PG_END_TRY();
+}
+
+#endif							/* LIBPQ_BE_FE_HELPERS_H */