MySQL Bugs: #45611: Minor code cleanup

Bug #45611	Minor code cleanup
Submitted:	19 Jun 2009 11:42	Modified:	14 Sep 2009 19:40
Reporter:	Michal Hrusecky	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Compiling	Severity:	S3 (Non-critical)
Version:	5.1.35	OS:	Linux
Assigned to:	Davi Arnaut	CPU Architecture:	Any
Tags:	Contribution

Description:
During compilation, gcc outputs some warning, I'll attach patch which fixes two of them.

First one is correcting obviously weird construction without any meaning.
Second one is a little correction preventing possible buffer overflow.

Found in 5.1.34, same thing applies for 5.1.35

How to repeat:
Try to compile and watchout for gcc warnings which looks serious.

Suggested fix:
Will follow

Patch to fix mentioned issues

Attachment: mysql-5.1.34-code-cleanup.patch (text/x-patch), 1.37 KiB.

Thank you for the report.

Which warnings do you get and which version of gcc do you use?

gcc version:
gcc (SUSE Linux) 4.4.0 [gcc-4_4-branch revision 148163]

Warnings:

For the first most obvious error:

../../../../../../storage/ndb/src/kernel/blocks/dbdict/Dbdict.cpp:7525: warning: operation on 'old_ptr_p' may be undefined

For the second less obvious one:

g++ -DHAVE_CONFIG_H -DNDEBUG -DDEFAULT_MYSQL_HOME="\"/usr\"" -DDATADIR="\"/var/lib/mysql\"" -DSHAREDIR="\"/usr/share/mysql\"" -DMYSQLCLUSTERDIR="\".\""  -I. -I../../../../../storage/ndb/src/mgmsrv -I../../../../include -I../../../../../storage/ndb/src/ndbapi -I../../../../../storage/ndb/src/mgmapi -I../../../../../storage/ndb/src/common/mgmcommon -I../../../../../storage/ndb/src/mgmclient -I../../../../../storage/ndb/src/mgmsrv -I../../../../include -I../../../../storage/ndb/include -I../../../../../include -I../../../../../mysys -I../../../../../storage/ndb/include -I../../../../../storage/ndb/include/kernel -I../../../../../storage/ndb/include/transporter -I../../../../../storage/ndb/include/debugger -I../../../../../storage/ndb/include/mgmapi -I../../../../../storage/ndb/include/mgmcommon -I../../../../../storage/ndb/include/ndbapi -I../../../../../storage/ndb/include/util -I../../../../../storage/ndb/include/portlib -I../../../../../storage/ndb/include/logger      -fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -DPIC -fPIC -DUNDEF_HAVE_INITGROUPS -DFORCE_INIT_OF_VARS -fno-strict-aliasing -fno-exceptions -fno-rtti   -fno-implicit-templates -fno-exceptions -fno-rtti -MT InitConfigFileParser.o -MD -MP -MF .deps/InitConfigFileParser.Tpo -c -o InitConfigFileParser.o ../../../../../storage/ndb/src/mgmsrv/InitConfigFileParser.cpp
In file included from /usr/include/string.h:640,
                 from ../../../../../include/m_string.h:30,
                 from ../../../../storage/ndb/include/ndb_global.h:58,
                 from ../../../../../storage/ndb/src/mgmsrv/InitConfigFileParser.cpp:16:
In function 'char* strncat(char*, const char*, size_t)',
    inlined from 'Config* InitConfigFileParser::run_config_rules(InitConfigFileParser::Context&)' at ../../../../../storage/ndb/src/mgmsrv/InitConfigFileParser.cpp:212:
/usr/include/bits/string3.h:153: warning: call to char* __builtin___strncat_chk(char*, const char*, long unsigned int, long unsigned int) might overflow destination buffer

Thank you for the feedback.

Bug is still not repeatable for me. Which configure options do you use? Please also try version 5.1.36 to see if problem solved.

5.1.36 is not released yet (or at least it is not available on download page).
It's warning only and I'm still able to compile MySQL, but it points out to
some more or less problematic pieces of code. And possible problems should be
obvious from attached patch. My compile options were following...

$ export 'CFLAGS=-fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -DPIC -fPIC -DUNDEF_HAVE_INITGROUPS -DFORCE_INIT_OF_VARS -fno-strict-aliasing'
$ CFLAGS='-fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -DPIC -fPIC -DUNDEF_HAVE_INITGROUPS -DFORCE_INIT_OF_VARS -fno-strict-aliasing'
$ export 'CXXFLAGS=-fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -DPIC -fPIC -DUNDEF_HAVE_INITGROUPS -DFORCE_INIT_OF_VARS -fno-strict-aliasing -fno-exceptions -fno-rtti'
$ CXXFLAGS='-fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -DPIC -fPIC -DUNDEF_HAVE_INITGROUPS -DFORCE_INIT_OF_VARS -fno-strict-aliasing -fno-exceptions -fno-rtti'
$ ../configure --enable-assembler --without-readline --infodir=/usr/share/info --libdir=/usr/lib64 --libexecdir=/usr/sbin --localstatedir=/var/lib/mysql --mandir=/usr/share/man --prefix=/usr --sysconfdir=/etc --with-mysqld-user=mysql --with-mysqld-group=mysql --without-debug --datadir=/usr/share --includedir=/usr/include --with-charset=utf8 --with-collation=utf8_unicode_ci --with-extra-charsets=complex --with-unix-socket-path=/var/run/mysql/mysql.sock --enable-thread-safe-client '--with-comment=SUSE MySQL RPM' --with-libwrap --with-server-suffix= --with-ssl=/usr --with-plugins=partition,csv,heap,myisam,ndbcluster,innobase 'HOSTNAME=/bin/hostname -f' --with-embedded-server

Many thanks for writing a bug report.

GCC 4.4 is not stable at the moment.

Do you have same issues by using GCC 4.3?

Susanne, why do you think that gcc 4.4 is "not stable"?
It has been officially released from http://gcc.gnu.org/

And as you can see, it's already used to compile the openSUSE Linux Distribution (Michal is the maintainer of the MySQL package on this distribution). So please reconsider setting the status of this bug to "verified" - it's a valuable contribution.

Michal, thank you for your patch, it's appreciated! Please keep them coming.

Lenz,

I was not able to repeat the problem. If this is repeatable for you set to "Verified" yourself, otherwise it should be open.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

Thank you for the feedback.

We are still not able to repeat the problem. Does it exist in version 5.1.37 in your environment?

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/82117

3095 Davi Arnaut	2009-09-01
      Bug#45611: Minor code cleanup
      
      Remove a self assignment.
      Rework a few constructs to avoid a potential overflow.
      
      Based upon patch contributed by Michal Hrusecky
     @ storage/ndb/src/kernel/blocks/dbdict/Dbdict.cpp
        Remove self assignment, the object is being initialized.
     @ storage/ndb/src/mgmsrv/InitConfigFileParser.cpp
        Setup the string in a single snprintf.

Queued to 5.1-bugteam

Pushed into 5.1.39 (revid:joro@sun.com-20090902154533-8actmfcsjfqovgsb) (version source revid:mattias.jonsson@sun.com-20090901135459-9v1p87eto9vxqq2s) (merge vers: 5.1.39) (pib:11)

No changelog entry needed.

Setting report to NDI pending push into 5.4.x.

Pushed into 5.4.4-alpha (revid:alik@sun.com-20090914155317-m1g9wodmndzdj4l1) (version source revid:alik@sun.com-20090914155317-m1g9wodmndzdj4l1) (merge vers: 5.4.4-alpha) (pib:11)

No changelog entry needed.

Pushed into 5.1.39-ndb-6.3.28 (revid:jonas@mysql.com-20091001055605-ap2kiaarr7p40mmv) (version source revid:jonas@mysql.com-20091001055605-ap2kiaarr7p40mmv) (merge vers: 5.1.39-ndb-6.3.28) (pib:11)

Pushed into 5.1.39-ndb-7.0.9 (revid:jonas@mysql.com-20091001072547-kv17uu06hfjhgjay) (version source revid:jonas@mysql.com-20091001071652-irejtnumzbpsbgk2) (merge vers: 5.1.39-ndb-7.0.9) (pib:11)

Pushed into 5.1.39-ndb-7.1.0 (revid:jonas@mysql.com-20091001123013-g9ob2tsyctpw6zs0) (version source revid:jonas@mysql.com-20091001123013-g9ob2tsyctpw6zs0) (merge vers: 5.1.39-ndb-7.1.0) (pib:11)

Pushed into 5.1.39-ndb-6.2.19 (revid:jonas@mysql.com-20091005103850-dwij2dojwpvf5hi6) (version source revid:jonas@mysql.com-20090930185117-bhud4ek1y0hsj1nv) (merge vers: 5.1.39-ndb-6.2.19) (pib:11)