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 is arguably a bug, but no backpatch is done now out of caution.

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

diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 7948bc5cb63701f3661d5c542a7b3109a9e05dcf..6900b27675e45f0bfe4099275ea8a7564ccdcddf 100644 (file)
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -552,11 +552,11 @@ 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))