| Bug #54166 | ha_rnd_init() result code not checked | ||
|---|---|---|---|
| Submitted: | 2 Jun 2010 5:02 | Modified: | 29 Jul 2012 22:43 |
| Reporter: | Stewart Smith | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Storage Engine API | Severity: | S2 (Serious) |
| Version: | 5.1 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[2 Jun 2010 18:47]
Sveta Smirnova
Thank you for the report. Verified as described: $cat bug54166.log | grep ha_rnd_init item_subselect.cc:2044: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:10854: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:13944: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:14072: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_update.cc:1976: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result log_event.cc:9063: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result log_event_old.cc:843: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result log_event_old.cc:2487: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:208: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:245: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:256: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result filesort.cc:538: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result handler.cc:2150: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result filesort.cc:538: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result handler.cc:2150: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result item_subselect.cc:2044: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:208: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:245: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result records.cc:256: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:10854: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:13944: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_select.cc:14072: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result sql_update.cc:1976: warning: ignoring return value of ‘int handler::ha_rnd_init(bool)’, declared with attribute warn_unused_result
[5 Jan 2011 16:16]
Mark Callaghan
Are there plans to fix this?
[11 Jan 2011 11:53]
Stewart Smith
MariaDB and Drizzle have implemented fixes (also for other handler calls).
[17 Feb 2011 7:08]
Stewart Smith
index_init is also affected. InnoDB has various workarounds (I've only audited parts of the codepath in Drizzle though, but it *should* be the same in MySQL 5.5 and thus okay) - see https://bugs.launchpad.net/drizzle/+bug/720552 MyISAM and NDB just set local vars, no problem. Other engines may have issues if they can possibly return an error from index_init and then not preserve it for subsequent index calls.
[29 Jul 2012 22:43]
Paul DuBois
Noted in 5.6.6 changelog. Code for the storage engine API did not check the return value from the ha_rnd_init() and ha_index_init() functions.
Description: This is about 10-15 bugs. If your storage engine has the nerve to return an error code from rnd_init() (as all documentation suggests you can, as well as the 'int' return type) a lot of places in the code don't check the return type, continue, and you can end up in a world of pain. It's also the case for rnd_end and other handler functions, but this is the one that bit me first. How to repeat: This patch produces a nice list of where they are (gcc only of course, but easy to wrap in a macro). --- ../mysql-5.1.46/sql/handler.h 2010-04-07 00:06:06.000000000 +1000 +++ sql/handler.h 2010-06-01 17:37:48.230727373 +1000 @@ -1188,7 +1188,7 @@ inited=NONE; DBUG_RETURN(index_end()); } - int ha_rnd_init(bool scan) + int ha_rnd_init(bool scan) __attribute__ ((warn_unused_result)) { int result; DBUG_ENTER("ha_rnd_init"); Suggested fix: -Werror and the above patch.