MySQL Bugs: #25097: mysql_server_init fails silently if no errmsg.sys is present

Bug #25097	mysql_server_init fails silently if no errmsg.sys is present
Submitted:	15 Dec 2006 15:45	Modified:	17 Mar 2008 20:29
Reporter:	Philip Stoev	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Embedded Library ( libmysqld )	Severity:	S3 (Non-critical)
Version:	5.1.14-beta	OS:	FreeBSD (FreeBSD)
Assigned to:	Alexey Botchkov	CPU Architecture:	Any
Tags:	qc

Description:
Hello,

if the default, charsets directory is not present and --character-sets-dir is not specified, mysql_server_init() will return 1, indicating error, however the exact reason for the error is not available and no error message is printed out.

How to repeat:
Do:

cd mysql-source-dir/sql/share
make uninstall

or:

/bin/rm -f -r /usr/local/share/mysql

and then call mysql_server_init()

Suggested fix:
Printing errors to the console from a library is not really a good idea, since they may interfere with the output of the actual program that is using libmysqld. Therefore mysql_server_init() should return more descriptive values than just 0 or 1.

The behavoir in question is caused by the vprint_msg_to_log function being replaced by a void one if EMBEDDED_LIBRARY is defined.

The problem comes not from missing charsets but from missing errmsg.sys in the share directory. Please see bug #13717 -- the patch in that bug silences not only warnings, but fatal errors as well.

Thank you for the bug report. Currently for version 5.0.XX the Embedded
Library isn't supported. Please see: http://dev.mysql.com/doc/refman/5.0/en/libmysqld.html

Wow, I did not know that :-) ./configure --with-embedded-server runs for me and does produce libmysqld.a.

Anyway, I will re-open the bug if 5.1 has the same problem.

It appears that the bug is still present in 5.1.14-beta.

vprint_msg_to_log() still does nothing when EMBEDDED_LIBRARY is defined. vprint_msg_to_log() is called directly by option_error_reporter() and indirectly by sql_print_error(), so no errors will be printed for mysql_server_init().

So as errors here can appear 
I think we should add 'mysql_server_errno() and mysql_server_error()' functions
to the API in order to handle that kind of problems logically.
Other option could be to make mysql_errno(NULL) and mysql_error(NULL) to return
the 'server' errors.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/42456

ChangeSet@1.2594, 2008-02-17 18:15:01+04:00, holyfoot@mysql.com +5 -0
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  There was no way to return an error from the client library
  if no MYSQL connections was established.
  So here i added variables to store that king of errors and
  made functions like mysql_error(NULL) to return these.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/43034

ChangeSet@1.2594, 2008-02-27 12:42:43+04:00, holyfoot@mysql.com +6 -0
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  There was no way to return an error from the client library
  if no MYSQL connections was established.
  So here i added variables to store that king of errors and
  made functions like mysql_error(NULL) to return these.

Pushed into 6.0.5-alpha

Pushed into 5.1.24-rc

Pushed into 5.0.60

Noted in 5.0.60, 5.1.24, 6.0.5 changelogs.

The client library had no way to return an error if no connection had
been established. This caused problems such as mysql_library_init()
failing silently if no errmsg.sys file was available.

Fixed also documented for 5.1.23-ndb-6.3.11.