Fix recently-introduced breakage in psql's \connect command.

Through my misreading of what the existing code actually did,
commits 85c54287a et al. broke psql's behavior for the case where
"\c connstring" provides a password in the connstring.  We should
use that password in such a case, but as of 85c54287a we ignored it
(and instead, prompted for a password).

Commit 94929f1cf fixed that in HEAD, but since I thought it was
cleaning up a longstanding misbehavior and not one I'd just created,
I didn't back-patch it.

Hence, back-patch the portions of 94929f1cf having to do with
password management.  In addition to fixing the introduced bug,
this means that "\c -reuse-previous=on connstring" will allow
re-use of an existing connection's password if the connstring
doesn't change user/host/port.  That didn't happen before, but
it seems like a bug fix, and anyway I'm loath to have significant
differences in this code across versions.

Also fix an error with the same root cause about whether or not to
override a connstring's setting of client_encoding.  As of 85c54287a
we always did so; restore the previous behavior of overriding only
when stdin/stdout are a terminal and there's no environment setting
of PGCLIENTENCODING.  (I find that definition a bit surprising, but
right now doesn't seem like the time to revisit it.)

Per bug #16746 from Krzysztof Gradek.  As with the previous patch,
back-patch to all supported branches.

Discussion: https://postgr.es/m/16746-44b30e2edf4335d4@postgresql.org

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 129d56a1d3b9f9093404c79986f9d750ed398c88..fa58f71e15ffb0c87f1b64a91450d74f50b56a2f 100644 (file)
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -911,6 +911,8 @@ testdb=>
         is changed from its previous value using the positional syntax,
         any <replaceable>hostaddr</replaceable> setting present in the
         existing connection's parameters is dropped.
+        Also, any password used for the existing connection will be re-used
+        only if the user, host, and port settings are not changed.
         When the command neither specifies nor reuses a particular parameter,
         the <application>libpq</application> default is used.
         </para>

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index dbce3248438a163704c95663aadb6c73a6e36597..40bc59409d068400e34de57df38f3fc78cf33c61 100644 (file)
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -2857,6 +2857,7 @@ do_connect(enum trivalue reuse_previous_specification,
    int         nconnopts = 0;
    bool        same_host = false;
    char       *password = NULL;
+   char       *client_encoding;
    bool        success = true;
    bool        keep_password = true;
    bool        has_connection_string;
@@ -2927,6 +2928,7 @@ do_connect(enum trivalue reuse_previous_specification,
            {
                PQconninfoOption *ci;
                PQconninfoOption *replci;
+               bool        have_password = false;
 
                for (ci = cinfo, replci = replcinfo;
                     ci->keyword && replci->keyword;
@@ -2945,6 +2947,26 @@ do_connect(enum trivalue reuse_previous_specification,
 
                        replci->val = ci->val;
                        ci->val = swap;
+
+                       /*
+                        * Check whether connstring provides options affecting
+                        * password re-use.  While any change in user, host,
+                        * hostaddr, or port causes us to ignore the old
+                        * connection's password, we don't force that for
+                        * dbname, since passwords aren't database-specific.
+                        */
+                       if (replci->val == NULL ||
+                           strcmp(ci->val, replci->val) != 0)
+                       {
+                           if (strcmp(replci->keyword, "user") == 0 ||
+                               strcmp(replci->keyword, "host") == 0 ||
+                               strcmp(replci->keyword, "hostaddr") == 0 ||
+                               strcmp(replci->keyword, "port") == 0)
+                               keep_password = false;
+                       }
+                       /* Also note whether connstring contains a password. */
+                       if (strcmp(replci->keyword, "password") == 0)
+                           have_password = true;
                    }
                }
                Assert(ci->keyword == NULL && replci->keyword == NULL);
@@ -2954,8 +2976,13 @@ do_connect(enum trivalue reuse_previous_specification,
 
                PQconninfoFree(replcinfo);
 
-               /* We never re-use a password with a conninfo string. */
-               keep_password = false;
+               /*
+                * If the connstring contains a password, tell the loop below
+                * that we may use it, regardless of other settings (i.e.,
+                * cinfo's password is no longer an "old" password).
+                */
+               if (have_password)
+                   keep_password = true;
 
                /* Don't let code below try to inject dbname into params. */
                dbname = NULL;
@@ -3043,14 +3070,16 @@ do_connect(enum trivalue reuse_previous_specification,
         */
        password = prompt_for_password(has_connection_string ? NULL : user);
    }
-   else if (o_conn && keep_password)
-   {
-       password = PQpass(o_conn);
-       if (password && *password)
-           password = pg_strdup(password);
-       else
-           password = NULL;
-   }
+
+   /*
+    * Consider whether to force client_encoding to "auto" (overriding
+    * anything in the connection string).  We do so if we have a terminal
+    * connection and there is no PGCLIENTENCODING environment setting.
+    */
+   if (pset.notty || getenv("PGCLIENTENCODING"))
+       client_encoding = NULL;
+   else
+       client_encoding = "auto";
 
    /* Loop till we have a connection or fail, which we might've already */
    while (success)
@@ -3062,12 +3091,12 @@ do_connect(enum trivalue reuse_previous_specification,
 
        /*
         * Copy non-default settings into the PQconnectdbParams parameter
-        * arrays; but override any values specified old-style, as well as the
-        * password and a couple of fields we want to set forcibly.
+        * arrays; but inject any values specified old-style, as well as any
+        * interactively-obtained password, and a couple of fields we want to
+        * set forcibly.
         *
         * If you change this code, see also the initial-connection code in
-        * main().  For no good reason, a connection string password= takes
-        * precedence in main() but not here.
+        * main().
         */
        for (ci = cinfo; ci->keyword; ci++)
        {
@@ -3086,12 +3115,15 @@ do_connect(enum trivalue reuse_previous_specification,
            }
            else if (port && strcmp(ci->keyword, "port") == 0)
                values[paramnum++] = port;
-           else if (strcmp(ci->keyword, "password") == 0)
+           /* If !keep_password, we unconditionally drop old password */
+           else if ((password || !keep_password) &&
+                    strcmp(ci->keyword, "password") == 0)
                values[paramnum++] = password;
            else if (strcmp(ci->keyword, "fallback_application_name") == 0)
                values[paramnum++] = pset.progname;
-           else if (strcmp(ci->keyword, "client_encoding") == 0)
-               values[paramnum++] = (pset.notty || getenv("PGCLIENTENCODING")) ? NULL : "auto";
+           else if (client_encoding &&
+                    strcmp(ci->keyword, "client_encoding") == 0)
+               values[paramnum++] = client_encoding;
            else if (ci->val)
                values[paramnum++] = ci->val;
            /* else, don't bother making libpq parse this keyword */