PQconninfoOption *conn_opt;
        char       *err_msg = NULL;
 
+       /* pg_recvlogical uses dbname only; others use connection_string only. */
+       Assert(dbname == NULL || connection_string == NULL);
+
        /*
         * Merge the connection info inputs given in form of connection string,
         * options and default values (dbname=replication, replication=true, etc.)
+        * Explicitly discard any dbname value in the connection string;
+        * otherwise, PQconnectdbParams() would interpret that value as being
+        * itself a connection string.
         */
        i = 0;
        if (connection_string)
 
                for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
                {
-                       if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
+                       if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+                               strcmp(conn_opt->keyword, "dbname") != 0)
                                argcount++;
                }
 
 
                for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
                {
-                       if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
+                       if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+                               strcmp(conn_opt->keyword, "dbname") != 0)
                        {
                                keywords[i] = conn_opt->keyword;
                                values[i] = conn_opt->val;
 
        SimpleStringList tableNames;
 
        int                     useDB;
-       char       *dbname;
+       char       *dbname;                     /* subject to expand_dbname */
        char       *pgport;
        char       *pghost;
        char       *username;
 
 typedef struct _dumpOptions
 {
-       const char *dbname;
+       const char *dbname;                     /* subject to expand_dbname */
        const char *pghost;
        const char *pgport;
        const char *username;
 
                /* If we created a DB, connect to it... */
                if (strcmp(te->desc, "DATABASE") == 0)
                {
+                       PQExpBufferData connstr;
+
+                       initPQExpBuffer(&connstr);
+                       appendPQExpBufferStr(&connstr, "dbname=");
+                       appendConnStrVal(&connstr, te->tag);
+                       /* Abandon struct, but keep its buffer until process exit. */
+
                        ahlog(AH, 1, "connecting to new database \"%s\"\n", te->tag);
                        _reconnectToDB(AH, te->tag);
-                       ropt->dbname = pg_strdup(te->tag);
+                       ropt->dbname = connstr.data;
                }
        }
 
                ReconnectToServer(AH, dbname, NULL);
        else
        {
-               PQExpBuffer qry = createPQExpBuffer();
+               if (dbname)
+               {
+                       PQExpBufferData connectbuf;
 
-               appendPQExpBuffer(qry, "\\connect %s\n\n",
-                                                 dbname ? fmtId(dbname) : "-");
-               ahprintf(AH, "%s", qry->data);
-               destroyPQExpBuffer(qry);
+                       initPQExpBuffer(&connectbuf);
+                       appendPsqlMetaConnect(&connectbuf, dbname);
+                       ahprintf(AH, "%s\n", connectbuf.data);
+                       termPQExpBuffer(&connectbuf);
+               }
+               else
+                       ahprintf(AH, "%s\n", "\\connect -\n");
        }
 
        /*
        }
        else
        {
-               char       *dbname;
+               PQExpBufferData connstr;
                char       *pghost;
                char       *pgport;
                char       *username;
                 * because all just return a pointer and do not actually send/receive
                 * any data to/from the database.
                 */
-               dbname = PQdb(AH->connection);
+               initPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, PQdb(AH->connection));
                pghost = PQhost(AH->connection);
                pgport = PQport(AH->connection);
                username = PQuser(AH->connection);
 
                /* this also sets clone->connection */
-               ConnectDatabase((Archive *) clone, dbname, pghost, pgport, username, TRI_NO);
+               ConnectDatabase((Archive *) clone, connstr.data,
+                                               pghost, pgport, username, TRI_NO);
 
+               termPQExpBuffer(&connstr);
                /* setupDumpWorker will fix up connection state */
        }
 
 
 #include "postgres_fe.h"
 
 #include "dumputils.h"
+#include "fe_utils/string_utils.h"
 #include "parallel.h"
 #include "pg_backup_archiver.h"
 #include "pg_backup_db.h"
 static PGconn *
 _connectDB(ArchiveHandle *AH, const char *reqdb, const char *requser)
 {
+       PQExpBufferData connstr;
        PGconn     *newConn;
        const char *newdb;
        const char *newuser;
                        exit_horribly(modulename, "out of memory\n");
        }
 
+       initPQExpBuffer(&connstr);
+       appendPQExpBuffer(&connstr, "dbname=");
+       appendConnStrVal(&connstr, newdb);
+
        do
        {
                const char *keywords[7];
                keywords[3] = "password";
                values[3] = password;
                keywords[4] = "dbname";
-               values[4] = newdb;
+               values[4] = connstr.data;
                keywords[5] = "fallback_application_name";
                values[5] = progname;
                keywords[6] = NULL;
        if (password)
                free(password);
 
+       termPQExpBuffer(&connstr);
+
        /* check for version mismatch */
        _check_database_version(AH);
 
 
                                                          fdbname, fmtId(dbtablespace));
 
                        /* connect to original database */
-                       appendPQExpBuffer(buf, "\\connect %s\n", fdbname);
+                       appendPsqlMetaConnect(buf, dbname);
                }
 
                if (binary_upgrade)
                int                     ret;
 
                char       *dbname = PQgetvalue(res, i, 0);
+               PQExpBufferData connectbuf;
 
                if (verbose)
                        fprintf(stderr, _("%s: dumping database \"%s\"...\n"), progname, dbname);
 
-               fprintf(OPF, "\\connect %s\n\n", fmtId(dbname));
+               initPQExpBuffer(&connectbuf);
+               appendPsqlMetaConnect(&connectbuf, dbname);
+               fprintf(OPF, "%s\n", connectbuf.data);
+               termPQExpBuffer(&connectbuf);
 
                /*
                 * Restore will need to write to the target cluster.  This connection
 
                /*
                 * Merge the connection info inputs given in form of connection string
-                * and other options.
+                * and other options.  Explicitly discard any dbname value in the
+                * connection string; otherwise, PQconnectdbParams() would interpret
+                * that value as being itself a connection string.
                 */
                if (connection_string)
                {
 
                        for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
                        {
-                               if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
+                               if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+                                       strcmp(conn_opt->keyword, "dbname") != 0)
                                        argcount++;
                        }
 
 
                        for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
                        {
-                               if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
+                               if (conn_opt->val != NULL && conn_opt->val[0] != '\0' &&
+                                       strcmp(conn_opt->keyword, "dbname") != 0)
                                {
                                        keywords[i] = conn_opt->keyword;
                                        values[i] = conn_opt->val;
 
        tablespace.o util.o version.o $(WIN32RES)
 
 override CPPFLAGS := -DDLSUFFIX=\"$(DLSUFFIX)\" -I$(srcdir) -I$(libpq_srcdir) $(CPPFLAGS)
+LDFLAGS += -L$(top_builddir)/src/fe_utils -lpgfeutils -lpq
 
 
 all: pg_upgrade
 
-pg_upgrade: $(OBJS) | submake-libpq submake-libpgport
+pg_upgrade: $(OBJS) | submake-libpq submake-libpgport submake-libpgfeutils
        $(CC) $(CFLAGS) $^ $(libpq_pgport) $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
 
 install: all installdirs
 
 #include "postgres_fe.h"
 
 #include "catalog/pg_authid.h"
+#include "fe_utils/string_utils.h"
 #include "mb/pg_wchar.h"
 #include "pg_upgrade.h"
 
 create_script_for_cluster_analyze(char **analyze_script_file_name)
 {
        FILE       *script = NULL;
-       char       *user_specification = "";
+       PQExpBufferData user_specification;
 
        prep_status("Creating script to analyze new cluster");
 
+       initPQExpBuffer(&user_specification);
        if (os_info.user_specified)
-               user_specification = psprintf("-U \"%s\" ", os_info.user);
+       {
+               appendPQExpBufferStr(&user_specification, "-U ");
+               appendShellString(&user_specification, os_info.user);
+               appendPQExpBufferChar(&user_specification, ' ');
+       }
 
        *analyze_script_file_name = psprintf("%sanalyze_new_cluster.%s",
                                                                                 SCRIPT_PREFIX, SCRIPT_EXT);
        fprintf(script, "echo %sthis script and run:%s\n",
                        ECHO_QUOTE, ECHO_QUOTE);
        fprintf(script, "echo %s    \"%s/vacuumdb\" %s--all %s%s\n", ECHO_QUOTE,
-                       new_cluster.bindir, user_specification,
+                       new_cluster.bindir, user_specification.data,
        /* Did we copy the free space files? */
                        (GET_MAJOR_VERSION(old_cluster.major_version) >= 804) ?
                        "--analyze-only" : "--analyze", ECHO_QUOTE);
        fprintf(script, "echo%s\n\n", ECHO_BLANK);
 
        fprintf(script, "\"%s/vacuumdb\" %s--all --analyze-in-stages\n",
-                       new_cluster.bindir, user_specification);
+                       new_cluster.bindir, user_specification.data);
        /* Did we copy the free space files? */
        if (GET_MAJOR_VERSION(old_cluster.major_version) < 804)
                fprintf(script, "\"%s/vacuumdb\" %s--all\n", new_cluster.bindir,
-                               user_specification);
+                               user_specification.data);
 
        fprintf(script, "echo%s\n\n", ECHO_BLANK);
        fprintf(script, "echo %sDone%s\n",
                                 *analyze_script_file_name, getErrorText());
 #endif
 
-       if (os_info.user_specified)
-               pg_free(user_specification);
+       termPQExpBuffer(&user_specification);
 
        check_ok();
 }
 
 #include "pg_upgrade.h"
 
 #include <sys/types.h>
+#include "fe_utils/string_utils.h"
 
 
 void
                char            sql_file_name[MAXPGPATH],
                                        log_file_name[MAXPGPATH];
                DbInfo     *old_db = &old_cluster.dbarr.dbs[dbnum];
+               PQExpBufferData connstr,
+                                       escaped_connstr;
+
+               initPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, old_db->db_name);
+               initPQExpBuffer(&escaped_connstr);
+               appendShellString(&escaped_connstr, connstr.data);
+               termPQExpBuffer(&connstr);
 
                pg_log(PG_STATUS, "%s", old_db->db_name);
                snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
 
                parallel_exec_prog(log_file_name, NULL,
                                   "\"%s/pg_dump\" %s --schema-only --quote-all-identifiers "
-                                 "--binary-upgrade --format=custom %s --file=\"%s\" \"%s\"",
+                                         "--binary-upgrade --format=custom %s --file=\"%s\" %s",
                                                 new_cluster.bindir, cluster_conn_opts(&old_cluster),
                                                   log_opts.verbose ? "--verbose" : "",
-                                                  sql_file_name, old_db->db_name);
+                                                  sql_file_name, escaped_connstr.data);
+
+               termPQExpBuffer(&escaped_connstr);
        }
 
        /* reap all children */
 
 
 #include "pg_upgrade.h"
 #include "common/restricted_token.h"
+#include "fe_utils/string_utils.h"
 
 #ifdef HAVE_LANGINFO_H
 #include <langinfo.h>
                char            sql_file_name[MAXPGPATH],
                                        log_file_name[MAXPGPATH];
                DbInfo     *old_db = &old_cluster.dbarr.dbs[dbnum];
+               PQExpBufferData connstr,
+                                       escaped_connstr;
+
+               initPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, old_db->db_name);
+               initPQExpBuffer(&escaped_connstr);
+               appendShellString(&escaped_connstr, connstr.data);
+               termPQExpBuffer(&connstr);
 
                pg_log(PG_STATUS, "%s", old_db->db_name);
                snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
                 */
                parallel_exec_prog(log_file_name,
                                                   NULL,
-                                                  "\"%s/pg_restore\" %s --exit-on-error --verbose --dbname \"%s\" \"%s\"",
+                "\"%s/pg_restore\" %s --exit-on-error --verbose --dbname %s \"%s\"",
                                                   new_cluster.bindir,
                                                   cluster_conn_opts(&new_cluster),
-                                                  old_db->db_name,
+                                                  escaped_connstr.data,
                                                   sql_file_name);
+
+               termPQExpBuffer(&escaped_connstr);
        }
 
        /* reap all children */
 
 
 #include "postgres_fe.h"
 
+#include "fe_utils/string_utils.h"
 #include "pg_upgrade.h"
 
 
 static PGconn *
 get_db_conn(ClusterInfo *cluster, const char *db_name)
 {
-       char            conn_opts[2 * NAMEDATALEN + MAXPGPATH + 100];
+       PQExpBufferData conn_opts;
+       PGconn     *conn;
 
+       /* Build connection string with proper quoting */
+       initPQExpBuffer(&conn_opts);
+       appendPQExpBufferStr(&conn_opts, "dbname=");
+       appendConnStrVal(&conn_opts, db_name);
+       appendPQExpBufferStr(&conn_opts, " user=");
+       appendConnStrVal(&conn_opts, os_info.user);
+       appendPQExpBuffer(&conn_opts, " port=%d", cluster->port);
        if (cluster->sockdir)
-               snprintf(conn_opts, sizeof(conn_opts),
-                                "dbname = '%s' user = '%s' host = '%s' port = %d",
-                                db_name, os_info.user, cluster->sockdir, cluster->port);
-       else
-               snprintf(conn_opts, sizeof(conn_opts),
-                                "dbname = '%s' user = '%s' port = %d",
-                                db_name, os_info.user, cluster->port);
+       {
+               appendPQExpBufferStr(&conn_opts, " host=");
+               appendConnStrVal(&conn_opts, cluster->sockdir);
+       }
 
-       return PQconnectdb(conn_opts);
+       conn = PQconnectdb(conn_opts.data);
+       termPQExpBuffer(&conn_opts);
+       return conn;
 }
 
 
  * sets, but the utilities we need aren't very consistent about the treatment
  * of database name options, so we leave that out.
  *
- * Note result is in static storage, so use it right away.
+ * Result is valid until the next call to this function.
  */
 char *
 cluster_conn_opts(ClusterInfo *cluster)
 {
-       static char conn_opts[MAXPGPATH + NAMEDATALEN + 100];
+       static PQExpBuffer buf;
 
-       if (cluster->sockdir)
-               snprintf(conn_opts, sizeof(conn_opts),
-                                "--host \"%s\" --port %d --username \"%s\"",
-                                cluster->sockdir, cluster->port, os_info.user);
+       if (buf == NULL)
+               buf = createPQExpBuffer();
        else
-               snprintf(conn_opts, sizeof(conn_opts),
-                                "--port %d --username \"%s\"",
-                                cluster->port, os_info.user);
+               resetPQExpBuffer(buf);
+
+       if (cluster->sockdir)
+       {
+               appendPQExpBufferStr(buf, "--host ");
+               appendShellString(buf, cluster->sockdir);
+               appendPQExpBufferChar(buf, ' ');
+       }
+       appendPQExpBuffer(buf, "--port %d --username ", cluster->port);
+       appendShellString(buf, os_info.user);
 
-       return conn_opts;
+       return buf->data;
 }
 
 
 
 
 standard_initdb "$oldbindir"/initdb
 "$oldbindir"/pg_ctl start -l "$logdir/postmaster1.log" -o "$POSTMASTER_OPTS" -w
+
+# Create databases with names covering the ASCII bytes other than NUL, BEL,
+# LF, or CR.  BEL would ring the terminal bell in the course of this test, and
+# it is not otherwise a special case.  PostgreSQL doesn't support the rest.
+dbname1=`awk 'BEGIN { for (i= 1; i < 46; i++)
+       if (i != 7 && i != 10 && i != 13) printf "%c", i }' </dev/null`
+# Exercise backslashes adjacent to double quotes, a Windows special case.
+dbname1='\"\'$dbname1'\\"\\\'
+dbname2=`awk 'BEGIN { for (i = 46; i <  91; i++) printf "%c", i }' </dev/null`
+dbname3=`awk 'BEGIN { for (i = 91; i < 128; i++) printf "%c", i }' </dev/null`
+createdb "$dbname1" || createdb_status=$?
+createdb "$dbname2" || createdb_status=$?
+createdb "$dbname3" || createdb_status=$?
+
 if "$MAKE" -C "$oldsrc" installcheck; then
        pg_dumpall -f "$temp_root"/dump1.sql || pg_dumpall1_status=$?
        if [ "$newsrc" != "$oldsrc" ]; then
        make_installcheck_status=$?
 fi
 "$oldbindir"/pg_ctl -m fast stop
+if [ -n "$createdb_status" ]; then
+       exit 1
+fi
 if [ -n "$make_installcheck_status" ]; then
        exit 1
 fi
 
 #include "postgres_fe.h"
 
 #include "pg_upgrade.h"
+#include "fe_utils/string_utils.h"
 
 
 
                        found = true;
                        if (!check_mode)
                        {
+                               PQExpBufferData connectbuf;
+
                                if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
                                        pg_fatal("could not open file \"%s\": %s\n", output_path, getErrorText());
-                               fprintf(script, "\\connect %s\n",
-                                               quote_identifier(active_db->db_name));
+
+                               initPQExpBuffer(&connectbuf);
+                               appendPsqlMetaConnect(&connectbuf, active_db->db_name);
+                               fputs(connectbuf.data, script);
+                               termPQExpBuffer(&connectbuf);
+
                                fprintf(script,
                                                "SELECT pg_catalog.lo_create(t.loid)\n"
                                                "FROM (SELECT DISTINCT loid FROM pg_catalog.pg_largeobject) AS t;\n");
 
        bool            keep_password;
        bool            has_connection_string;
        bool            reuse_previous;
+       PQExpBufferData connstr;
 
        if (!o_conn && (!dbname || !user || !host || !port))
        {
         * changes: passwords aren't (usually) database-specific.
         */
        if (!dbname && reuse_previous)
-               dbname = PQdb(o_conn);
+       {
+               initPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, PQdb(o_conn));
+               dbname = connstr.data;
+               /* has_connection_string=true would be a dead store */
+       }
+       else
+               connstr.data = NULL;
 
        /*
         * If the user asked to be prompted for a password, ask for one now. If
                }
 
                PQfinish(n_conn);
+               if (connstr.data)
+                       termPQExpBuffer(&connstr);
                return false;
        }
+       if (connstr.data)
+               termPQExpBuffer(&connstr);
 
        /*
         * Replace the old connection with the new one, and update
 
 #include "postgres_fe.h"
 #include "common.h"
 #include "fe_utils/simple_list.h"
+#include "fe_utils/string_utils.h"
 
 
 static void cluster_one_database(const char *dbname, bool verbose, const char *table,
 {
        PGconn     *conn;
        PGresult   *result;
+       PQExpBufferData connstr;
        int                     i;
 
        conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
        result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", progname, echo);
        PQfinish(conn);
 
+       initPQExpBuffer(&connstr);
        for (i = 0; i < PQntuples(result); i++)
        {
                char       *dbname = PQgetvalue(result, i, 0);
                        fflush(stdout);
                }
 
-               cluster_one_database(dbname, verbose, NULL,
+               resetPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, dbname);
+
+               cluster_one_database(connstr.data, verbose, NULL,
                                                         host, port, username, prompt_password,
                                                         progname, echo);
        }
+       termPQExpBuffer(&connstr);
 
        PQclear(result);
 }
 
 {
        PGconn     *conn;
        PGresult   *result;
+       PQExpBufferData connstr;
        int                     i;
 
        conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
        result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", progname, echo);
        PQfinish(conn);
 
+       initPQExpBuffer(&connstr);
        for (i = 0; i < PQntuples(result); i++)
        {
                char       *dbname = PQgetvalue(result, i, 0);
                        fflush(stdout);
                }
 
-               reindex_one_database(dbname, dbname, "DATABASE", host, port, username,
-                                                        prompt_password, progname, echo, verbose);
+               resetPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, dbname);
+
+               reindex_one_database(NULL, connstr.data, "DATABASE", host,
+                                                        port, username, prompt_password,
+                                                        progname, echo, verbose);
        }
+       termPQExpBuffer(&connstr);
 
        PQclear(result);
 }
        if (verbose)
                appendPQExpBuffer(&sql, " (VERBOSE)");
 
-       appendPQExpBuffer(&sql, " SYSTEM %s;", PQdb(conn));
+       appendPQExpBuffer(&sql, " SYSTEM %s;", fmtId(PQdb(conn)));
 
        if (!executeMaintenanceCommand(conn, sql.data, echo))
        {
 
 {
        PGconn     *conn;
        PGresult   *result;
+       PQExpBufferData connstr;
        int                     stage;
        int                     i;
 
                                                  progname, echo);
        PQfinish(conn);
 
+       initPQExpBuffer(&connstr);
        if (analyze_in_stages)
        {
                /*
                {
                        for (i = 0; i < PQntuples(result); i++)
                        {
-                               const char *dbname;
+                               resetPQExpBuffer(&connstr);
+                               appendPQExpBuffer(&connstr, "dbname=");
+                               appendConnStrVal(&connstr, PQgetvalue(result, i, 0));
 
-                               dbname = PQgetvalue(result, i, 0);
-                               vacuum_one_database(dbname, vacopts,
+                               vacuum_one_database(connstr.data, vacopts,
                                                                        stage,
                                                                        NULL,
                                                                        host, port, username, prompt_password,
        {
                for (i = 0; i < PQntuples(result); i++)
                {
-                       const char *dbname;
+                       resetPQExpBuffer(&connstr);
+                       appendPQExpBuffer(&connstr, "dbname=");
+                       appendConnStrVal(&connstr, PQgetvalue(result, i, 0));
 
-                       dbname = PQgetvalue(result, i, 0);
-                       vacuum_one_database(dbname, vacopts,
+                       vacuum_one_database(connstr.data, vacopts,
                                                                ANALYZE_NO_STAGE,
                                                                NULL,
                                                                host, port, username, prompt_password,
                                                                progname, echo, quiet);
                }
        }
+       termPQExpBuffer(&connstr);
 
        PQclear(result);
 }
 
        bool            needquotes;
 
        /*
-        * If the string consists entirely of plain ASCII characters, no need to
-        * quote it. This is quite conservative, but better safe than sorry.
+        * If the string is one or more plain ASCII characters, no need to quote
+        * it. This is quite conservative, but better safe than sorry.
         */
-       needquotes = false;
+       needquotes = true;
        for (s = str; *s; s++)
        {
                if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
                        needquotes = true;
                        break;
                }
+               needquotes = false;
        }
 
        if (needquotes)
 }
 
 
+/*
+ * Append a psql meta-command that connects to the given database with the
+ * then-current connection's user, host and port.
+ */
+void
+appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname)
+{
+       const char *s;
+       bool            complex;
+
+       /*
+        * If the name is plain ASCII characters, emit a trivial "\connect "foo"".
+        * For other names, even many not technically requiring it, skip to the
+        * general case.  No database has a zero-length name.
+        */
+       complex = false;
+       for (s = dbname; *s; s++)
+       {
+               if (*s == '\n' || *s == '\r')
+               {
+                       fprintf(stderr,
+                                       _("database name contains a newline or carriage return: \"%s\"\n"),
+                                       dbname);
+                       exit(EXIT_FAILURE);
+               }
+
+               if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
+                         (*s >= '0' && *s <= '9') || *s == '_' || *s == '.'))
+               {
+                       complex = true;
+               }
+       }
+
+       appendPQExpBufferStr(buf, "\\connect ");
+       if (complex)
+       {
+               PQExpBufferData connstr;
+
+               initPQExpBuffer(&connstr);
+               appendPQExpBuffer(&connstr, "dbname=");
+               appendConnStrVal(&connstr, dbname);
+
+               appendPQExpBuffer(buf, "-reuse-previous=on ");
+
+               /*
+                * As long as the name does not contain a newline, SQL identifier
+                * quoting satisfies the psql meta-command parser.  Prefer not to
+                * involve psql-interpreted single quotes, which behaved differently
+                * before PostgreSQL 9.2.
+                */
+               appendPQExpBufferStr(buf, fmtId(connstr.data));
+
+               termPQExpBuffer(&connstr);
+       }
+       else
+               appendPQExpBufferStr(buf, fmtId(dbname));
+       appendPQExpBufferChar(buf, '\n');
+}
+
+
 /*
  * Deconstruct the text representation of a 1-dimensional Postgres array
  * into individual items.
 
 
 extern void appendShellString(PQExpBuffer buf, const char *str);
 extern void appendConnStrVal(PQExpBuffer buf, const char *str);
+extern void appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname);
 
 extern bool parsePGArray(const char *atext, char ***itemarray, int *nitems);
 
 
  * of "dbname" keyword is a connection string (as indicated by
  * recognized_connection_string) then parse and process it, overriding any
  * previously processed conflicting keywords. Subsequent keywords will take
- * precedence, however.
+ * precedence, however. In-tree programs generally specify expand_dbname=true,
+ * so command-line arguments naming a database can use a connection string.
+ * Some code acquires arbitrary database names from known-literal sources like
+ * PQdb(), PQconninfoParse() and pg_database.datname.  When connecting to such
+ * a database, in-tree code first wraps the name in a connection string.
  */
 static PQconninfoOption *
 conninfo_array_parse(const char *const * keywords, const char *const * values,
 
                        $ENV{PGDATA}) == 0);
 }
 
+# This is similar to appendShellString().  Perl system(@args) bypasses
+# cmd.exe, so omit the caret escape layer.
+sub quote_system_arg
+{
+       my $arg = shift;
+
+       # Change N >= 0 backslashes before a double quote to 2N+1 backslashes.
+       $arg =~ s/(\\*)"/${\($1 . $1)}\\"/gs;
+
+       # Change N >= 1 backslashes at end of argument to 2N backslashes.
+       $arg =~ s/(\\+)$/${\($1 . $1)}/gs;
+
+       # Wrap the whole thing in unescaped double quotes.
+       return "\"$arg\"";
+}
+
+# Generate a database with a name made of a range of ASCII characters, useful
+# for testing pg_upgrade.
+sub generate_db
+{
+       my ($prefix, $from_char, $to_char, $suffix) = @_;
+
+       my $dbname = $prefix;
+       for my $i ($from_char .. $to_char)
+       {
+               next if $i == 7 || $i == 10 || $i == 13;    # skip BEL, LF, and CR
+               $dbname = $dbname . sprintf('%c', $i);
+       }
+       $dbname .= $suffix;
+
+       system('createdb', quote_system_arg($dbname));
+       my $status = $? >> 8;
+       exit $status if $status;
+}
+
 sub upgradecheck
 {
        my $status;
        print "\nStarting old cluster\n\n";
        my @args = ('pg_ctl', 'start', '-l', "$logdir/postmaster1.log", '-w');
        system(@args) == 0 or exit 1;
+
+       print "\nCreating databases with names covering most ASCII bytes\n\n";
+       generate_db("\\\"\\", 1,  45,  "\\\\\"\\\\\\");
+       generate_db('',       46, 90,  '');
+       generate_db('',       91, 127, '');
+
        print "\nSetting up data for upgrading\n\n";
        installcheck();