Register atexit hook only once in pg_upgrade.

start_postmaster() registered stop_postmaster_atexit as an atexit(3)
callback each time through, although the obvious intention was to do
so only once per program run.  The extra registrations were harmless,
so long as we didn't exceed ATEXIT_MAX, but still it's a bug.

Artur Zakirov, with bikeshedding by Kyotaro Horiguchi and me

Discussion: <d279e817-02b5-caa6-215f-cfb05dce109a@postgrespro.ru>

diff --git a/src/bin/pg_upgrade/server.c b/src/bin/pg_upgrade/server.c
index 8c6b6da515305a9d9648cc05adc3d3292a16e1f6..a1a8b098e6c95f327a91acb879200573d07e1068 100644 (file)
--- a/src/bin/pg_upgrade/server.c
+++ b/src/bin/pg_upgrade/server.c
@@ -174,10 +174,11 @@ start_postmaster(ClusterInfo *cluster, bool throw_error)
 {
    char        cmd[MAXPGPATH * 4 + 1000];
    PGconn     *conn;
-   bool        exit_hook_registered = false;
    bool        pg_ctl_return = false;
    char        socket_string[MAXPGPATH + 200];
 
+   static bool exit_hook_registered = false;
+
    if (!exit_hook_registered)
    {
        atexit(stop_postmaster_atexit);