Remove HAVE_UNIX_SOCKETS.

Since HAVE_UNIX_SOCKETS is now defined unconditionally, remove the macro
and drop a small amount of dead code.

The last known systems not to have them (as far as I know at least) were
QNX, which we de-supported years ago, and Windows, which now has them.

If a new OS ever shows up with the POSIX sockets API but without working
AF_UNIX, it'll presumably still be able to compile the code, and fail at
runtime with an unsupported address family error.  We might want to
consider adding a HINT that you should turn off the option to use it if
your network stack doesn't support it at that point, but it doesn't seem
worth making the relevant code conditional at compile time.

Also adjust a couple of places in the docs and comments that referred to
builds without Unix-domain sockets, since there aren't any.  Windows
still gets a special mention in those places, though, because we don't
try to use them by default there yet.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2BL_3brvh%3D8e0BW_VfX9h7MtwgN%3DnFHP5o7X2oZucY9dg%40mail.gmail.com

doc/src/sgml/libpq.sgml

@@ -1070,9 +1070,8 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
         specified, or is empty, is to connect to a Unix-domain
         socket<indexterm><primary>Unix domain socket</primary></indexterm> in
         <filename>/tmp</filename> (or whatever socket directory was specified
-        when <productname>PostgreSQL</productname> was built).  On Windows and
+        when <productname>PostgreSQL</productname> was built).  On Windows,
-        on machines without Unix-domain sockets, the default is to connect to
+        the default is to connect to <literal>localhost</literal>.
-        <literal>localhost</literal>.
        </para>
        <para>
         A comma-separated list of host names is also accepted, in which case
@@ -1152,8 +1151,8 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
        <para>
         Without either a host name or host address,
         <application>libpq</application> will connect using a local
-        Unix-domain socket; or on Windows and on machines without Unix-domain
+        Unix-domain socket; or on Windows, it will attempt to connect to
-        sockets, it will attempt to connect to <literal>localhost</literal>.
+        <literal>localhost</literal>.
        </para>
        </listitem>
       </varlistentry>

doc/src/sgml/ref/psql-ref.sgml

@@ -656,7 +656,7 @@ EOF
     of these options are required; there are useful defaults. If you omit the host
     name, <application>psql</application> will connect via a Unix-domain socket
     to a server on the local host, or via TCP/IP to <literal>localhost</literal> on
-    machines that don't have Unix-domain sockets. The default port number is
+    Windows. The default port number is
     determined at compile time.
     Since the database server uses the same default, you will not have
     to specify the port in most cases. The default user name is your

src/backend/libpq/hba.c

@@ -973,17 +973,7 @@ parse_hba_line(TokenizedAuthLine *tok_line, int elevel)
 	token = linitial(tokens);
 	if (strcmp(token->string, "local") == 0)
 	{
-#ifdef HAVE_UNIX_SOCKETS
 		parsedline->conntype = ctLocal;
-#else
-		ereport(elevel,
-				(errcode(ERRCODE_CONFIG_FILE_ERROR),
-				 errmsg("local connections are not supported by this build"),
-				 errcontext("line %d of configuration file \"%s\"",
-							line_num, HbaFileName)));
-		*err_msg = "local connections are not supported by this build";
-		return NULL;
-#endif
 	}
 	else if (strcmp(token->string, "host") == 0 ||
 			 strcmp(token->string, "hostssl") == 0 ||

src/backend/libpq/pqcomm.c

@@ -149,10 +149,8 @@ static void socket_putmessage_noblock(char msgtype, const char *s, size_t len);
 static int	internal_putbytes(const char *s, size_t len);
 static int	internal_flush(void);
 
-#ifdef HAVE_UNIX_SOCKETS
 static int	Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath);
 static int	Setup_AF_UNIX(const char *sock_path);
-#endif							/* HAVE_UNIX_SOCKETS */
 
 static const PQcommMethods PqCommSocketMethods = {
 	socket_comm_reset,
@@ -334,10 +332,7 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 	struct addrinfo hint;
 	int			listen_index = 0;
 	int			added = 0;
-
-#ifdef HAVE_UNIX_SOCKETS
 	char		unixSocketPath[MAXPGPATH];
-#endif
 #if !defined(WIN32) || defined(IPV6_V6ONLY)
 	int			one = 1;
 #endif
@@ -348,7 +343,6 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 	hint.ai_flags = AI_PASSIVE;
 	hint.ai_socktype = SOCK_STREAM;
 
-#ifdef HAVE_UNIX_SOCKETS
 	if (family == AF_UNIX)
 	{
 		/*
@@ -369,7 +363,6 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 		service = unixSocketPath;
 	}
 	else
-#endif							/* HAVE_UNIX_SOCKETS */
 	{
 		snprintf(portNumberStr, sizeof(portNumberStr), "%d", portNumber);
 		service = portNumberStr;
@@ -427,11 +420,9 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 				familyDesc = _("IPv6");
 				break;
 #endif
-#ifdef HAVE_UNIX_SOCKETS
 			case AF_UNIX:
 				familyDesc = _("Unix");
 				break;
-#endif
 			default:
 				snprintf(familyDescBuf, sizeof(familyDescBuf),
 						 _("unrecognized address family %d"),
@@ -441,11 +432,9 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 		}
 
 		/* set up text form of address for log messages */
-#ifdef HAVE_UNIX_SOCKETS
 		if (addr->ai_family == AF_UNIX)
 			addrDesc = unixSocketPath;
 		else
-#endif
 		{
 			pg_getnameinfo_all((const struct sockaddr_storage *) addr->ai_addr,
 							   addr->ai_addrlen,
@@ -540,7 +529,6 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 			continue;
 		}
 
-#ifdef HAVE_UNIX_SOCKETS
 		if (addr->ai_family == AF_UNIX)
 		{
 			if (Setup_AF_UNIX(service) != STATUS_OK)
@@ -549,7 +537,6 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 				break;
 			}
 		}
-#endif
 
 		/*
 		 * Select appropriate accept-queue length limit.  PG_SOMAXCONN is only
@@ -572,13 +559,11 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 			continue;
 		}
 
-#ifdef HAVE_UNIX_SOCKETS
 		if (addr->ai_family == AF_UNIX)
 			ereport(LOG,
 					(errmsg("listening on Unix socket \"%s\"",
 							addrDesc)));
 		else
-#endif
 			ereport(LOG,
 			/* translator: first %s is IPv4 or IPv6 */
 					(errmsg("listening on %s address \"%s\", port %d",
@@ -597,8 +582,6 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 }
 
 
-#ifdef HAVE_UNIX_SOCKETS
-
 /*
  * Lock_AF_UNIX -- configure unix socket file path
  */
@@ -699,7 +682,6 @@ Setup_AF_UNIX(const char *sock_path)
 	}
 	return STATUS_OK;
 }
-#endif							/* HAVE_UNIX_SOCKETS */
 
 
 /*

src/backend/postmaster/postmaster.c

@@ -1297,7 +1297,6 @@ PostmasterMain(int argc, char *argv[])
 	}
 #endif
 
-#ifdef HAVE_UNIX_SOCKETS
 	if (Unix_socket_directories)
 	{
 		char	   *rawstring;
@@ -1347,7 +1346,6 @@ PostmasterMain(int argc, char *argv[])
 		list_free_deep(elemlist);
 		pfree(rawstring);
 	}
-#endif
 
 	/*
 	 * check that we have some socket to listen on

src/backend/utils/misc/guc.c

@@ -4452,11 +4452,7 @@ static struct config_string ConfigureNamesString[] =
 			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
 		},
 		&Unix_socket_directories,
-#ifdef HAVE_UNIX_SOCKETS
 		DEFAULT_PGSOCKET_DIR,
-#else
-		"",
-#endif
 		NULL, NULL, NULL
 	},
 

src/bin/initdb/initdb.c

@@ -242,9 +242,6 @@ static char backend_exec[MAXPGPATH];
 static char **replace_token(char **lines,
 							const char *token, const char *replacement);
 
-#ifndef HAVE_UNIX_SOCKETS
-static char **filter_lines_with_token(char **lines, const char *token);
-#endif
 static char **readfile(const char *path);
 static void writefile(char *path, char **lines);
 static FILE *popen_check(const char *command, const char *mode);
@@ -418,36 +415,6 @@ replace_token(char **lines, const char *token, const char *replacement)
 	return result;
 }
 
-/*
- * make a copy of lines without any that contain the token
- *
- * a sort of poor man's grep -v
- */
-#ifndef HAVE_UNIX_SOCKETS
-static char **
-filter_lines_with_token(char **lines, const char *token)
-{
-	int			numlines = 1;
-	int			i,
-				src,
-				dst;
-	char	  **result;
-
-	for (i = 0; lines[i]; i++)
-		numlines++;
-
-	result = (char **) pg_malloc(numlines * sizeof(char *));
-
-	for (src = 0, dst = 0; src < numlines; src++)
-	{
-		if (lines[src] == NULL || strstr(lines[src], token) == NULL)
-			result[dst++] = lines[src];
-	}
-
-	return result;
-}
-#endif
-
 /*
  * get the lines from a text file
  */
@@ -1045,12 +1012,8 @@ setup_config(void)
 				 n_buffers * (BLCKSZ / 1024));
 	conflines = replace_token(conflines, "#shared_buffers = 128MB", repltok);
 
-#ifdef HAVE_UNIX_SOCKETS
 	snprintf(repltok, sizeof(repltok), "#unix_socket_directories = '%s'",
 			 DEFAULT_PGSOCKET_DIR);
-#else
-	snprintf(repltok, sizeof(repltok), "#unix_socket_directories = ''");
-#endif
 	conflines = replace_token(conflines, "#unix_socket_directories = '/tmp'",
 							  repltok);
 
@@ -1210,11 +1173,7 @@ setup_config(void)
 
 	conflines = readfile(hba_file);
 
-#ifndef HAVE_UNIX_SOCKETS
-	conflines = filter_lines_with_token(conflines, "@remove-line-for-nolocal@");
-#else
 	conflines = replace_token(conflines, "@remove-line-for-nolocal@", "");
-#endif
 
 #ifdef HAVE_IPV6
 

src/bin/pg_upgrade/option.c

@@ -444,7 +444,7 @@ adjust_data_dir(ClusterInfo *cluster)
 void
 get_sock_dir(ClusterInfo *cluster, bool live_check)
 {
-#if defined(HAVE_UNIX_SOCKETS) && !defined(WIN32)
+#if !defined(WIN32)
 	if (!live_check)
 		cluster->sockdir = user_opts.socketdir;
 	else
@@ -490,7 +490,7 @@ get_sock_dir(ClusterInfo *cluster, bool live_check)
 			pg_log(PG_WARNING, "user-supplied old port number %hu corrected to %hu",
 				   orig_port, cluster->port);
 	}
-#else							/* !HAVE_UNIX_SOCKETS || WIN32 */
+#else							/* WIN32 */
 	cluster->sockdir = NULL;
 #endif
 }

src/bin/pg_upgrade/server.c

@@ -212,7 +212,7 @@ start_postmaster(ClusterInfo *cluster, bool report_and_exit_on_error)
 
 	socket_string[0] = '\0';
 
-#if defined(HAVE_UNIX_SOCKETS) && !defined(WIN32)
+#if !defined(WIN32)
 	/* prevent TCP/IP connections, restrict socket access */
 	strcat(socket_string,
 		   " -c listen_addresses='' -c unix_socket_permissions=0700");

src/common/ip.c

@@ -38,7 +38,6 @@
 
 
 
-#ifdef	HAVE_UNIX_SOCKETS
 static int	getaddrinfo_unix(const char *path,
 							 const struct addrinfo *hintsp,
 							 struct addrinfo **result);
@@ -47,7 +46,6 @@ static int	getnameinfo_unix(const struct sockaddr_un *sa, int salen,
 							 char *node, int nodelen,
 							 char *service, int servicelen,
 							 int flags);
-#endif
 
 
 /*
@@ -62,10 +60,8 @@ pg_getaddrinfo_all(const char *hostname, const char *servname,
 	/* not all versions of getaddrinfo() zero *result on failure */
 	*result = NULL;
 
-#ifdef HAVE_UNIX_SOCKETS
 	if (hintp->ai_family == AF_UNIX)
 		return getaddrinfo_unix(servname, hintp, result);
-#endif
 
 	/* NULL has special meaning to getaddrinfo(). */
 	rc = getaddrinfo((!hostname || hostname[0] == '\0') ? NULL : hostname,
@@ -87,7 +83,6 @@ pg_getaddrinfo_all(const char *hostname, const char *servname,
 void
 pg_freeaddrinfo_all(int hint_ai_family, struct addrinfo *ai)
 {
-#ifdef HAVE_UNIX_SOCKETS
 	if (hint_ai_family == AF_UNIX)
 	{
 		/* struct was built by getaddrinfo_unix (see pg_getaddrinfo_all) */
@@ -101,7 +96,6 @@ pg_freeaddrinfo_all(int hint_ai_family, struct addrinfo *ai)
 		}
 	}
 	else
-#endif							/* HAVE_UNIX_SOCKETS */
 	{
 		/* struct was built by getaddrinfo() */
 		if (ai != NULL)
@@ -126,14 +120,12 @@ pg_getnameinfo_all(const struct sockaddr_storage *addr, int salen,
 {
 	int			rc;
 
-#ifdef HAVE_UNIX_SOCKETS
 	if (addr && addr->ss_family == AF_UNIX)
 		rc = getnameinfo_unix((const struct sockaddr_un *) addr, salen,
 							  node, nodelen,
 							  service, servicelen,
 							  flags);
 	else
-#endif
 		rc = getnameinfo((const struct sockaddr *) addr, salen,
 						 node, nodelen,
 						 service, servicelen,
@@ -151,8 +143,6 @@ pg_getnameinfo_all(const struct sockaddr_storage *addr, int salen,
 }
 
 
-#if defined(HAVE_UNIX_SOCKETS)
-
 /* -------
  *	getaddrinfo_unix - get unix socket info using IPv6-compatible API
  *
@@ -286,4 +276,3 @@ getnameinfo_unix(const struct sockaddr_un *sa, int salen,
 
 	return 0;
 }
-#endif							/* HAVE_UNIX_SOCKETS */

src/include/port.h

@@ -503,7 +503,4 @@ extern bool wait_result_is_any_signal(int exit_status, bool include_command_not_
 #define HAVE_SYMLINK 1
 #endif
 
-/* Interfaces that we assume that all systems have. */
-#define HAVE_UNIX_SOCKETS 1
-
 #endif							/* PG_PORT_H */

src/interfaces/libpq/fe-connect.c

@@ -1102,10 +1102,8 @@ connectOptions2(PGconn *conn)
 		else if (ch->host != NULL && ch->host[0] != '\0')
 		{
 			ch->type = CHT_HOST_NAME;
-#ifdef HAVE_UNIX_SOCKETS
 			if (is_unixsock_path(ch->host))
 				ch->type = CHT_UNIX_SOCKET;
-#endif
 		}
 		else
 		{
@@ -1115,14 +1113,12 @@ connectOptions2(PGconn *conn)
 			 * This bit selects the default host location.  If you change
 			 * this, see also pg_regress.
 			 */
-#ifdef HAVE_UNIX_SOCKETS
 			if (DEFAULT_PGSOCKET_DIR[0])
 			{
 				ch->host = strdup(DEFAULT_PGSOCKET_DIR);
 				ch->type = CHT_UNIX_SOCKET;
 			}
 			else
-#endif
 			{
 				ch->host = strdup(DefaultHost);
 				ch->type = CHT_HOST_NAME;
@@ -1684,7 +1680,6 @@ getHostaddr(PGconn *conn, char *host_addr, int host_addr_len)
 static void
 emitHostIdentityInfo(PGconn *conn, const char *host_addr)
 {
-#ifdef HAVE_UNIX_SOCKETS
 	if (conn->raddr.addr.ss_family == AF_UNIX)
 	{
 		char		service[NI_MAXHOST];
@@ -1698,7 +1693,6 @@ emitHostIdentityInfo(PGconn *conn, const char *host_addr)
 						  service);
 	}
 	else
-#endif							/* HAVE_UNIX_SOCKETS */
 	{
 		const char *displayed_host;
 		const char *displayed_port;
@@ -1748,12 +1742,10 @@ connectFailureMessage(PGconn *conn, int errorno)
 					  "%s\n",
 					  SOCK_STRERROR(errorno, sebuf, sizeof(sebuf)));
 
-#ifdef HAVE_UNIX_SOCKETS
 	if (conn->raddr.addr.ss_family == AF_UNIX)
 		appendPQExpBufferStr(&conn->errorMessage,
 							 libpq_gettext("\tIs the server running locally and accepting connections on that socket?\n"));
 	else
-#endif
 		appendPQExpBufferStr(&conn->errorMessage,
 							 libpq_gettext("\tIs the server running on that host and accepting TCP/IP connections?\n"));
 }
@@ -2415,7 +2407,6 @@ keep_going:						/* We will come back to here until there is
 				break;
 
 			case CHT_UNIX_SOCKET:
-#ifdef HAVE_UNIX_SOCKETS
 				conn->addrlist_family = hint.ai_family = AF_UNIX;
 				UNIXSOCK_PATH(portstr, thisport, ch->host);
 				if (strlen(portstr) >= UNIXSOCK_PATH_BUFLEN)
@@ -2440,9 +2431,6 @@ keep_going:						/* We will come back to here until there is
 									  portstr, gai_strerror(ret));
 					goto keep_going;
 				}
-#else
-				Assert(false);
-#endif
 				break;
 		}
 

src/test/regress/pg_regress.c

@@ -99,11 +99,9 @@ static char *logfilename;
 static FILE *logfile;
 static char *difffilename;
 static const char *sockdir;
-#ifdef HAVE_UNIX_SOCKETS
 static const char *temp_sockdir;
 static char sockself[MAXPGPATH];
 static char socklock[MAXPGPATH];
-#endif
 
 static _resultmap *resultmap = NULL;
 
@@ -285,7 +283,6 @@ stop_postmaster(void)
 	}
 }
 
-#ifdef HAVE_UNIX_SOCKETS
 /*
  * Remove the socket temporary directory.  pg_regress never waits for a
  * postmaster exit, so it is indeterminate whether the postmaster has yet to
@@ -360,7 +357,6 @@ make_temp_sockdir(void)
 
 	return temp_sockdir;
 }
-#endif							/* HAVE_UNIX_SOCKETS */
 
 /*
  * Check whether string matches pattern
@@ -683,7 +679,6 @@ initialize_environment(void)
 		/* PGPORT, see below */
 		/* PGHOST, see below */
 
-#ifdef HAVE_UNIX_SOCKETS
 		if (hostname != NULL)
 			setenv("PGHOST", hostname, 1);
 		else
@@ -693,10 +688,6 @@ initialize_environment(void)
 				sockdir = make_temp_sockdir();
 			setenv("PGHOST", sockdir, 1);
 		}
-#else
-		Assert(hostname != NULL);
-		setenv("PGHOST", hostname, 1);
-#endif
 		unsetenv("PGHOSTADDR");
 		if (port != -1)
 		{
@@ -746,11 +737,9 @@ initialize_environment(void)
 		if (!pghost)
 		{
 			/* Keep this bit in sync with libpq's default host location: */
-#ifdef HAVE_UNIX_SOCKETS
 			if (DEFAULT_PGSOCKET_DIR[0])
 				 /* do nothing, we'll print "Unix socket" below */ ;
 			else
-#endif
 				pghost = "localhost";	/* DefaultHost in fe-connect.c */
 		}
 
@@ -2068,14 +2057,11 @@ regression_main(int argc, char *argv[],
 
 	atexit(stop_postmaster);
 
-#if !defined(HAVE_UNIX_SOCKETS)
+#if defined(WIN32)
-	use_unix_sockets = false;
-#elif defined(WIN32)
 
 	/*
-	 * We don't use Unix-domain sockets on Windows by default, even if the
+	 * We don't use Unix-domain sockets on Windows by default (see comment at
-	 * build supports them.  (See comment at remove_temp() for a reason.)
+	 * remove_temp() for a reason).  Override at your own risk.
-	 * Override at your own risk.
 	 */
 	use_unix_sockets = getenv("PG_TEST_USE_UNIX_SOCKETS") ? true : false;
 #else
@@ -2209,7 +2195,7 @@ regression_main(int argc, char *argv[],
 		/*
 		 * To reduce chances of interference with parallel installations, use
 		 * a port number starting in the private range (49152-65535)
-		 * calculated from the version number.  This aids !HAVE_UNIX_SOCKETS
+		 * calculated from the version number.  This aids non-Unix socket mode
 		 * systems; elsewhere, the use of a private socket directory already
 		 * prevents interference.
 		 */
@@ -2329,8 +2315,6 @@ regression_main(int argc, char *argv[],
 			snprintf(buf, sizeof(buf), "%s/data", temp_instance);
 			config_sspi_auth(buf, NULL);
 		}
-#elif !defined(HAVE_UNIX_SOCKETS)
-#error Platform has no means to secure the test installation.
 #endif
 
 		/*