Thread: pg_dump: fix crash on error
If pg_dump fails to connect to Postgres, it attempts to print an error
message in ConnectDatabase():
/* check to see that the backend connection was successfully made */
if (PQstatus(AH->connection) == CONNECTION_BAD)
die_horribly(AH, modulename,
"connection to database \"%s\" failed: %s",
dbname, PQerrorMessage(AH->connection));
But if no database is explicitly specified, `dbname' is NULL, and libc
is entitled to crash if you pass a NULL pointer to it for a %s
formatting sequence (it actually does crash on Solaris, for example --
per report from Omar Kilani).
Attached is a patch that fixes this by just removing `dbname' from the
error message, as PQerrorMessage() should provide enough information.
Barring any objections, I'll apply this to HEAD and back branches within
24 hours.
-Neil
Index: src/bin/pg_dump/pg_backup_db.c
===================================================================
RCS file: /var/lib/cvs/pgsql/src/bin/pg_dump/pg_backup_db.c,v
retrieving revision 1.63
diff -c -r1.63 pg_backup_db.c
*** src/bin/pg_dump/pg_backup_db.c 1 Jul 2005 21:03:25 -0000 1.63
--- src/bin/pg_dump/pg_backup_db.c 27 Jul 2005 01:23:27 -0000
***************
*** 265,272 ****
/* check to see that the backend connection was successfully made */
if (PQstatus(AH->connection) == CONNECTION_BAD)
! die_horribly(AH, modulename, "connection to database \"%s\" failed: %s",
! dbname, PQerrorMessage(AH->connection));
/* check for version mismatch */
_check_database_version(AH, ignoreVersion);
--- 265,272 ----
/* check to see that the backend connection was successfully made */
if (PQstatus(AH->connection) == CONNECTION_BAD)
! die_horribly(AH, modulename, "connection to database failed: %s",
! PQerrorMessage(AH->connection));
/* check for version mismatch */
_check_database_version(AH, ignoreVersion);
Neil Conway <neilc@samurai.com> writes:
> If pg_dump fails to connect to Postgres, it attempts to print an error
> message in ConnectDatabase():
> ...
> But if no database is explicitly specified, `dbname' is NULL, and libc
> is entitled to crash if you pass a NULL pointer to it for a %s
> formatting sequence (it actually does crash on Solaris, for example --
> per report from Omar Kilani).
[ scratches head... ] Did this code change recently? It's a tad hard
to believe that such a thing could have gone unnoticed for long.
regards, tom lane
Tom Lane wrote: > [ scratches head... ] Did this code change recently? It's a tad hard > to believe that such a thing could have gone unnoticed for long. Seems the problem was introduced here: http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_db.c.diff?r1=1.58;r2=1.59 (I could just revert the code to using PQdb(), but I don't think there's a need to mention the database in the error message ourselves -- PQerrorMessage() should include that information if appropriate.) -Neil
Neil Conway <neilc@samurai.com> writes: > Tom Lane wrote: >> [ scratches head... ] Did this code change recently? It's a tad hard >> to believe that such a thing could have gone unnoticed for long. > Seems the problem was introduced here: > http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_db.c.diff?r1=1.58;r2=1.59 Oh dear, that makes it my fault :-( > (I could just revert the code to using PQdb(), but I don't think there's > a need to mention the database in the error message ourselves -- > PQerrorMessage() should include that information if appropriate.) I'd go with reverting it to using PQdb, myself. Looks like I got bit by the perennial mantra: premature optimization is the root of all evil. regards, tom lane
Tom Lane wrote: > I'd go with reverting it to using PQdb, myself. Fair enough; reverted to using PQdb(), and applied to HEAD and REL8_0_STABLE. -Neil