pg_ctl: Disable autoruns for cmd.exe on Windows

On Windows, cmd.exe is used to launch the postmaster process to ease its
redirection setup.  However, cmd.exe may execute other programs at
startup due to autorun configurations, which could influence the
postmaster startup.  This patch adds /D flag to the launcher cmd.exe
command line to disable autorun settings written in the registry.

This was originally applied on HEAD as of 9886744a361b without a
backpatch, but the patch has survived CI and buildfarm cycles.  I have
checked that cmd /d exists down to Windows XP, which should make this
change work correctly in the oldest branches still supported.

Reported-by: Hayato Kuroda
Author: Kyotaro Horiguchi
Reviewed-by: Robert Haas, Michael Paquier
Discussion: https://postgr.es/m/20230922.161551.320043332510268554.horikyota.ntt@gmail.com
Backpatch-through: 12

diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 01b815d4a0768cdab13df3663376460d341e520c..091d584d82a04de9d588a399354a7873e2fc2b05 100644 (file)
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -559,11 +559,11 @@ start_postmaster(void)
                else
                        close(fd);
 
-               cmd = psprintf("\"%s\" /C \"\"%s\" %s%s < \"%s\" >> \"%s\" 2>&1\"",
+               cmd = psprintf("\"%s\" /D /C \"\"%s\" %s%s < \"%s\" >> \"%s\" 2>&1\"",
                                           comspec, exec_path, pgdata_opt, post_opts, DEVNULL, log_file);
        }
        else
-               cmd = psprintf("\"%s\" /C \"\"%s\" %s%s < \"%s\" 2>&1\"",
+               cmd = psprintf("\"%s\" /D /C \"\"%s\" %s%s < \"%s\" 2>&1\"",
                                           comspec, exec_path, pgdata_opt, post_opts, DEVNULL);
 
        if (!CreateRestrictedProcess(cmd, &pi, false))