Give a better error message on invalid hostaddr option.

If you accidentally pass a host name in the hostaddr option, e.g.
hostaddr=localhost, you get an error like:

psql: could not translate host name "localhost" to address: Name or service not known

That's a bit confusing, because it implies that we tried to look up
"localhost" in DNS, but it failed. To make it more clear that we tried to
parse "localhost" as a numeric network address, change the message to:

psql: could not parse network address "localhost": Name or service not known

Discussion: https://www.postgresql.org/message-id/10badbc6-4d5a-a769-623a-f7ada43e14dd@iki.fi

diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 77b170af94dfb95ed3c4749e4c67f8a12d25e23c..c1dfa5eb9798fc5c1485600d68661aebc970ed0c 100644 (file)
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -1642,7 +1642,6 @@ connectDBStart(PGconn *conn)
    for (i = 0; i < conn->nconnhost; ++i)
    {
        pg_conn_host *ch = &conn->connhost[i];
-       char       *node = ch->host;
        struct addrinfo hint;
        int         thisport;
 
@@ -1668,17 +1667,28 @@ connectDBStart(PGconn *conn)
        }
        snprintf(portstr, sizeof(portstr), "%d", thisport);
 
-       /* Set up for name resolution. */
+       /* Use pg_getaddrinfo_all() to resolve the address */
        switch (ch->type)
        {
            case CHT_HOST_NAME:
+               ret = pg_getaddrinfo_all(ch->host, portstr, &hint, &ch->addrlist);
+               if (ret || !ch->addrlist)
+                   appendPQExpBuffer(&conn->errorMessage,
+                                     libpq_gettext("could not translate host name \"%s\" to address: %s\n"),
+                                     ch->host, gai_strerror(ret));
                break;
+
            case CHT_HOST_ADDRESS:
                hint.ai_flags = AI_NUMERICHOST;
+               ret = pg_getaddrinfo_all(ch->host, portstr, &hint, &ch->addrlist);
+               if (ret || !ch->addrlist)
+                   appendPQExpBuffer(&conn->errorMessage,
+                                     libpq_gettext("could not parse network address \"%s\": %s\n"),
+                                     ch->host, gai_strerror(ret));
                break;
+
            case CHT_UNIX_SOCKET:
 #ifdef HAVE_UNIX_SOCKETS
-               node = NULL;
                hint.ai_family = AF_UNIX;
                UNIXSOCK_PATH(portstr, thisport, ch->host);
                if (strlen(portstr) >= UNIXSOCK_PATH_BUFLEN)
@@ -1690,24 +1700,25 @@ connectDBStart(PGconn *conn)
                    conn->options_valid = false;
                    goto connect_errReturn;
                }
+
+               /*
+                * NULL hostname tells pg_getaddrinfo_all to parse the service
+                * name as a Unix-domain socket path.
+                */
+               ret = pg_getaddrinfo_all(NULL, portstr, &hint, &ch->addrlist);
+               if (ret || !ch->addrlist)
+                   appendPQExpBuffer(&conn->errorMessage,
+                                     libpq_gettext("could not translate Unix-domain socket path \"%s\" to address: %s\n"),
+                                     portstr, gai_strerror(ret));
+               break;
 #else
                Assert(false);
+               conn->options_valid = false;
+               goto connect_errReturn;
 #endif
-               break;
        }
-
-       /* Use pg_getaddrinfo_all() to resolve the address */
-       ret = pg_getaddrinfo_all(node, portstr, &hint, &ch->addrlist);
        if (ret || !ch->addrlist)
        {
-           if (node)
-               appendPQExpBuffer(&conn->errorMessage,
-                                 libpq_gettext("could not translate host name \"%s\" to address: %s\n"),
-                                 node, gai_strerror(ret));
-           else
-               appendPQExpBuffer(&conn->errorMessage,
-                                 libpq_gettext("could not translate Unix-domain socket path \"%s\" to address: %s\n"),
-                                 portstr, gai_strerror(ret));
            if (ch->addrlist)
            {
                pg_freeaddrinfo_all(hint.ai_family, ch->addrlist);