Improve timezone mapping for AIX platform

Fri Apr 4 13:22:33 UTC 2014

Hi Jonathan,

sorry, but I found a few more issues:

- please use strncpy instead of strcpy in TimeZone_md.c:798 otherwise
somebody could easily crash the VM by specifying a TZ with more than
100 characters.

- you can delete the lines 871-872 because the variables are actually
not used and you can also remove the handling for "timezone == 0"
because that is actually done in getGMTOffsetID() anyway.

- could you please avoid the usage of strtok. It is not intended for
usage in a multithreaded environment (see for example "man strtok" on
AIX). strtok_r is probably overkill, but you could use for example
strchr.

did you check the build on Windows?

Thank you and best regards,
Volker

On Fri, Apr 4, 2014 at 10:18 AM, Jonathan Lu <luchsh at linux.vnet.ibm.com> wrote:
> Hi Volker, Masayoshi,
>
> I made another  patch which fixed the problems mentioned in last mail,
>
> http://cr.openjdk.java.net/~luchsh/JDK-8034220.v3/
>
> Could you pls help to take a look?
>
> Many thanks
> Jonathan
>
>
>
> On Thu, Apr 3, 2014 at 12:34 AM, Jonathan Lu <luchsh at linux.vnet.ibm.com>
> wrote:
>>
>> Hi Volker,
>>
>>
>> On 2014年04月02日 23:07, Volker Simonis wrote:
>>
>> Hi Jonathan,
>>
>> thanks for updating the change. Please find my comments inline:
>>
>> On Tue, Apr 1, 2014 at 4:52 PM, Jonathan Lu <luchsh at linux.vnet.ibm.com>
>> wrote:
>>
>> Hi Volker, Masayoshi,
>>
>> Thanks a lot for your review, here's the updated patch, could you pls take
>> a
>> look?
>>
>> http://cr.openjdk.java.net/~luchsh/JDK-8034220.v2/
>>
>>
>> On Thu, Mar 27, 2014 at 1:48 AM, Volker Simonis <volker.simonis at gmail.com>
>> wrote:
>>
>> Hi Jonathan,
>>
>> thanks for doing this change. Please find some comments below:
>>
>> 1. please update the copyright year to 2014 in every file you touch
>>
>> Updated in new patch.
>>
>> 2. in CopyFiles.gmk you can simplify the change by joining the windows
>> and aix cases because on Windows OPENJDK_TARGET_OS is the same like
>> OPENJDK_TARGET_OS_API_DIR. So you can write:
>>
>> ifneq ($(findstring $(OPENJDK_TARGET_OS), windows aix), )
>>
>>   TZMAPPINGS_SRC := $(JDK_TOPDIR)/src/$(OPENJDK_TARGET_OS)/lib
>>
>>   $(LIBDIR)/tzmappings: $(TZMAPPINGS_SRC)/tzmappings
>>     $(call install-file)
>>
>>   COPY_FILES += $(LIBDIR)/tzmappings
>>
>> endif
>>
>> I've tried that approach before, but OPENJDK_TARGET_OS_API_DIR is
>> 'solaris'
>> as I observed on my AIX box,
>> solaris/lib is not the directory where tzmappings was stored for AIX.
>> So I'm keeping this change, please fix me if I was wrong about the config.
>>
>> Yes, but my point was to actually use OPENJDK_TARGET_OS for the
>> construction of  TZMAPPINGS_SRC as shown in the code snippet above.
>> OPENJDK_TARGET_OS is "windows" on Windows platforms and "aix" on AIX
>> and that should be just enough here.
>>
>>
>> That's right, let me try that  and also build/test on Windows platform.
>>
>>
>> 3. regarding the changes proposed by Masayoshi: I agree that we should
>> put the AIX timezone mapping code in its own function, but I don't
>> think that getPlatformTimeZoneID() would be the right place. As far as
>> I understand, getPlatformTimeZoneID() is used to get a platform time
>> zone id if the environment variable "TZ" is not set. I don't know a
>> way how this could be done on AIX (@Jonathan: maybe you know?). If
>> there would be a way to get the time zone from some system files or
>> so, then we should put this code into the AIX version of
>> getPlatformTimeZoneID().
>>
>> I guess we may try to use /etc/envrionment file, which is basic setting
>> for
>> all processes,
>> see
>>
>> http://publib.boulder.ibm.com/infocenter/aix/v7r1/index.jsp?topic=%2Fcom.ibm.aix.files%2Fdoc%2Faixfiles%2Fenvironment.htm
>> The implementation of  getPlatformTimeZoneID() has been updated.
>>
>> That's good!
>>
>> But the current AIX code contributed by Jonathan, actually uses the
>> time zone id from the "TZ" environment variable and just maps it to a
>> Java compatible time zone id. So I'd suggest to refactor this code
>> into a function like for example "static const char*
>> mapPlatformToJavaTimzone(const char* tz)" and call that from
>> findJavaTZ_md(). I think that would make the code easier to
>> understand.
>>
>> Agree, and have split the code into a separate static method to do the
>> mapping work.
>>
>> Good. But there's still one error in findJavaTZ_md():
>>
>>  706 #ifdef _AIX
>>  707         javatz = mapPlatformToJavaTimezone(java_home_dir, tz);
>>  708 #endif
>>
>> This should read:
>>
>>  706 #ifdef _AIX
>>  707         javatz = mapPlatformToJavaTimezone(java_home_dir, javatz);
>>  708 #endif
>>
>> because in line 703 you free 'tz' via its alias 'freetz' if 'tz' came
>> from getPlatformTimeZoneID().
>>
>>
>> Right, but with the second approach, there may be a minor memory leak
>> here,
>> as javatz was not freed before being overwritten on AIX. will post another
>> patch on this soon.
>>
>>
>> With the above fixed I'll push this one we get one more review from a
>> reviewer (I'm currently not an official reviewer).
>>
>> Regards,
>> Volker
>>
>>
>> @Masayoshi: what do you think, would you agree with such a solution.
>>
>> 4. I agree with Masayoshi that you should use the existing
>> getGMTOffsetID()
>>
>> Updated in new patch to eliminate duplication.
>>
>> 5. Please notice that your change breaks all Unix builds except AIX
>> because of:
>>
>>  759     }
>>  760 tzerr:
>>  761     if (javatz == NULL) {
>>  762         time_t offset;
>> ...
>>  782     }
>>  783 #endif
>>
>> I think that should read:
>>
>>  759
>>  760     tzerr:
>>  761         if (javatz == NULL) {
>>  762             time_t offset;
>> ...
>>  782         }
>>  783 #endif
>>  784     }
>>
>> Refactoring the code in an extra function will make that error more
>> evident anyway.
>>
>> But please always build at least on one different platform (i.e.
>> Linux) to prevent such errors in the future.
>>
>> My fault, sorry for the failure, should take no chance after any manual
>> alteration.
>>
>> Regards,
>> Volker
>>
>>
>> On Wed, Mar 26, 2014 at 10:27 AM, Masayoshi Okutsu
>> <masayoshi.okutsu at oracle.com> wrote:
>>
>> Hi Jonathan,
>>
>> The AIX specific code looks OK to me. But I'd suggest the code be moved
>> to
>> getPlatformTimeZoneID() for AIX, which just returns NULL currently. Also
>> there's a function for producing a fallback ID in "GMT±hh:mm",
>> getGMTOffsetID() which can be called in tzerr.
>>
>> Thanks,
>> Masayoshi
>>
>>
>> On 3/26/2014 3:47 PM, Jonathan Lu wrote:
>>
>> Hi ppc-aix-port-dev, core-libs-dev,
>>
>> Here's a patch for JDK-8034220,
>>
>> http://cr.openjdk.java.net/~luchsh/JDK-8034220/
>>
>> It is trying to add the a more complete timezone mapping mechanism for
>> AIX
>> platform.
>> the changes are primarily based on IBM's commercial JDK code, which
>> includes:
>>
>> - A new timezone mapping file added under directory jdk/src/aix/lib/
>> - Code to parse above config file, changed file is
>> src/solaris/native/java/util/TimeZone_md.c
>> - And also makefile change in make/CopyFiles.gmk to copy the config
>> file
>>
>> Could you pls help to review and give comments ?
>>
>> Cheers
>> - Jonathan
>>
>> Many thanks
>> Jonathan
>>
>> Regards
>> Jonathan
>
>