From 9dcd1aa815f5911bc7d526cdfee85ae493b5e12c Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 17 Jul 2025 12:46:38 -0400 Subject: [PATCH] Fix PQport to never return NULL unless the connection is NULL. This is the documented behavior, and it worked that way before v10. However, addition of the connhost[] array created cases where conn->connhost[conn->whichhost].port is NULL. The rest of libpq is careful to substitute DEF_PGPORT[_STR] for a null or empty port string, but we failed to do so here, leading to possibly returning NULL. As of v18 that causes psql's \conninfo command to segfault. Older psql versions avoid that, but it's pretty likely that other clients have trouble with this, so we'd better back-patch the fix. In stable branches, just revert to our historical behavior of returning an empty string when there was no user-given port specification. However, it seems substantially more useful and indeed more correct to hand back DEF_PGPORT_STR in such cases, so let's make v18 and master do that. Author: Daniele Varrazzo Reviewed-by: Laurenz Albe Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CA+mi_8YTS8WPZPO0PAb2aaGLwHuQ0DEQRF0ZMnvWss4y9FwDYQ@mail.gmail.com Backpatch-through: 13 --- src/interfaces/libpq/fe-connect.c | 4 +++- src/interfaces/libpq/libpq-int.h | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index be028d628b1..9b781c35002 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -6646,7 +6646,9 @@ PQport(const PGconn *conn) if (!conn) return NULL; - if (conn->connhost != NULL) + if (conn->connhost != NULL && + conn->connhost[conn->whichhost].port != NULL && + conn->connhost[conn->whichhost].port[0] != '\0') return conn->connhost[conn->whichhost].port; return ""; diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h index 668a5c87498..4b065486530 100644 --- a/src/interfaces/libpq/libpq-int.h +++ b/src/interfaces/libpq/libpq-int.h @@ -311,7 +311,8 @@ typedef struct pg_conn_host pg_conn_host_type type; /* type of host address */ char *host; /* host name or socket path */ char *hostaddr; /* host numeric IP address */ - char *port; /* port number (always provided) */ + char *port; /* port number (if NULL or empty, use + * DEF_PGPORT[_STR]) */ char *password; /* password for this host, read from the * password file; NULL if not sought or not * found in password file. */