Yes, it is also my interpretation that the correct way to do it is to call tzset() just before localtime_r(). But it puzzles me why tzset() is not called from within localtime_r(), if tzset() is thread-safe.
/ Anders Widell On 07/17/2014 06:19 AM, Mathivanan Naickan Palanivelu wrote: > I find the man page cryptic, but the following discussion helps understand > the problems > that can happen when tzset() is not called: > > http://stackoverflow.com/questions/19170721/real-time-awareness-of-timezone-change-in-localtime-vs-localtime-r > > Will call tzset() just before localtime_r. > > Mathi. > > ----- anders.wid...@ericsson.com wrote: > >> Looked a bit further into tzset(), and from what I can see, this >> function is safe to call in a multi-threaded program: >> >> http://www.gnu.org/software/libc/manual/html_node/Time-Zone-Functions.html >> >> So we could actually place the call to tzset() just before each call >> to >> localtime_r(), instead of calling it in a start-up function. The >> benefit >> would be that we handle the case when the TZ environment variable is >> modified. >> >> / Anders Widell >> >> On 07/16/2014 04:29 PM, Anders Widell wrote: >>> Yes, it seems like a good idea to call tzset(), e.g. in some >> library >>> function that is always called early at start-up. >>> >>> / Anders Widell >>> >>> On 07/16/2014 03:57 PM, Alex Jones wrote: >>>> One comment. From the man page of localtime_r: >>>> >>>> According to POSIX.1-2004, localtime() is required to behave as >> though >>>> tzset(3) was called, while localtime_r() does not have >> this >>>> require- >>>> ment. For portable code tzset(3) should be called >> before >>>> local- >>>> time_r(). > w> >> >>>> Do we need to do this? >>>> >>>> Alex >>>> >>>> On 07/16/2014 04:37 AM, mathi.naic...@oracle.com wrote: >>>>> Summary: replace localtime with thread safe localtime_r [#958] >>>>> Review request for Trac Ticket(s): #958 >>>>> Peer Reviewer(s): ramesh, mahesh, hans, praveen, nagendra, alex >>>>> Pull request to: <<LIST THE PERSON WITH PUSH ACCESS HERE>> >>>>> Affected branch(es): 4.3.x, 4.4.x >>>>> Development branch: <<IF ANY GIVE THE REPO URL>> >>>>> >>>>> -------------------------------- >>>>> Impacted area Impact y/n >>>>> -------------------------------- >>>>> Docs n >>>>> Build system n >>>>> RPM/packaging n >>>>> Configuration files n >>>>> Startup scripts n >>>>> SAF services y >>>>> OpenSAF services y >>>>> Core libraries n >>>>> Samples n >>>>> Tests n >>>>> Other n >>>>> >>>>> >>>>> Comments (indicate scope for each "y" above): >>>>> --------------------------------------------- >>>>> localtime is not thread safe and because of this, crashes have >> been >>>>> observed in multithreaded opensaf services (for eg:- a crash in >> SMFD >>>>> because logtrace uses localtime). >>>>> The patch series replaces all occurrences of localtime with >> localtime_r. >>>>> changeset 8cbe68c97884d76c15e3e65c04c1e677402676c3 >>>>> Author: mathi.naic...@oracle.com >>>>> Date: Wed, 16 Jul 2014 13:51:31 +0530 >>>>> >>>>> osaf: use thread safe localtime_r instead of localtime [#958] >> localtime is >>>>> not thread safe and it can(has) cause crashes in services that >> are multi >>>>> threaded. >>>>> >>>>> changeset 3123adbd8bd655db83216e17d33ee4ae034496f3 >>>>> Author: mathi.naic...@oracle.com >>>>> Date: Wed, 16 Jul 2014 13:52:06 +0530 >>>>> >>>>> mds: use thread safe localtime_r instead of localtime [#958] >> localtime is >>>>> not thread safe and it can(has) cause crashes in services that >> are multi >>>>> threaded. >>>>> >>>>> changeset 80940ead9b9233e895a10992d45d7a1b37c2e791 >>>>> Author: mathi.naic...@oracle.com >>>>> Date: Wed, 16 Jul 2014 13:55:09 +0530 >>>>> >>>>> amf: use thread safe localtime_r instead of localtime [#958] >> localtime is >>>>> not thread safe and it can(has) cause crashes in services that >> are multi >>>>> threaded. >>>>> >>>>> changeset 24833293883ba7c68b7fe1e303cadc05cf361e94 >>>>> Author: mathi.naic...@oracle.com >>>>> Date: Wed, 16 Jul 2014 13:55:47 +0530 >>>>> >>>>> ntf: use thread safe localtime_r instead of localtime [#958] >> localtime is >>>>> not thread safe and it can(has) cause crashes in services that >> are multi >>>>> threaded. >>>>> >>>>> changeset facf9779833cecd83118a88527e60d235f6af6c8 >>>>> Author: mathi.naic...@oracle.com >>>>> Date: Wed, 16 Jul 2014 13:57:46 +0530 >>>>> >>>>> plm: use thread safe localtime_r instead of localtime [#958] >> localtime is >>>>> not thread safe and it can(has) cause crashes in services that >> are multi >>>>> threaded. >>>>> >>>>> >>>>> Complete diffstat: >>>>> ------------------ >>>>> osaf/libs/core/common/include/logtrace.h | 2 +- >>>>> osaf/libs/core/common/logtrace.c | 6 +++++- >>>>> osaf/libs/core/mds/mds_log.c | 6 +++++- >>>>> osaf/services/saf/amf/amfwdog/amf_wdog.c | 6 +++++- >>>>> osaf/services/saf/ntfsv/ntfs/ntfs_evt.c | 6 +++++- >>>>> osaf/services/saf/plmsv/plms/plms_dbg_utils.c | 6 +++++- >>>>> osaf/tools/safntf/src/ntfclient.c | 6 +++++- >>>>> 7 files changed, 31 insertions(+), 7 deletions(-) >>>>> >>>>> >>>>> Testing Commands: >>>>> ----------------- >>>>> Start opensaf, observe timestamp wherever(flows) applicable. >>>>> >>>>> Testing, Expected Results: >>>>> -------------------------- >>>>> Start opensaf, observe timestamp wherever applicable. >>>>> >>>>> >>>>> Conditions of Submission: >>>>> ------------------------- >>>>> Ack from Reviewers. >>>>> >>>>> Arch Built Started Linux distro >>>>> ------------------------------------------- >>>>> mips n n >>>>> mips64 n n >>>>> x86 n n >>>>> x86_64 y y >>>>> powerpc n n >>>>> powerpc64 n n >>>>> >>>>> >>>>> Reviewer Checklist: >>>>> ------------------- >>>>> [Submitters: make sure that your review doesn't trigger any >> checkmarks!] >>>>> >>>>> Your checkin has not passed review because (see checked entries): >>>>> >>>>> ___ Your RR template is generally incomplete; it has too many >> blank entries >>>>> that need proper data filled in. >>>>> >>>>> ___ You have failed to nominate the proper persons for review and >> push. >>>>> ___ Your patches do not have proper short+long header >>>>> >>>>> ___ You have grammar/spelling in your header that is >> unacceptable. >>>>> ___ You have exceeded a sensible line length in your >> headers/comments/text. >>>>> ___ You have failed to put in a proper Trac Ticket # into your >> commits. >>>>> ___ You have incorrectly put/left internal data in your >> comments/files >>>>> (i.e. internal bug tracking tool IDs, product names etc) >>>>> >>>>> ___ You have not given any evidence of testing beyond basic build >> tests. >>>>> Demonstrate some level of runtime or other sanity testing. >>>>> >>>>> ___ You have ^M present in some of your files. These have to be >> removed. >>>>> ___ You have needlessly changed whitespace or added whitespace >> crimes >>>>> like trailing spaces, or spaces before tabs. >>>>> >>>>> ___ You have mixed real technical changes with whitespace and >> other >>>>> cosmetic code cleanup changes. These have to be separate >> commits. >>>>> ___ You need to refactor your submission into logical chunks; >> there is >>>>> too much content into a single commit. >>>>> >>>>> ___ You have extraneous garbage in your review (merge commits >> etc) >>>>> ___ You have giant attachments which should never have been sent; >>>>> Instead you should place your content in a public tree to >> be pulled. >>>>> ___ You have too many commits attached to an e-mail; resend as >> threaded >>>>> commits, or place in a public tree for a pull. >>>>> >>>>> ___ You have resent this content multiple times without a clear >> indication >>>>> of what has changed between each re-send. >>>>> >>>>> ___ You have failed to adequately and individually address all of >> the >>>>> comments and change requests that were proposed in the >> initial review. >>>>> ___ You have a misconfigured ~/.hgrc file (i.e. username, email >> etc) >>>>> ___ Your computer have a badly configured date and time; confusing >> the >>>>> the threaded patch review. >>>>> >>>>> ___ Your changes affect IPC mechanism, and you don't present any >> results >>>>> for in-service upgradability test. >>>>> >>>>> ___ Your changes affect user manual and documentation, your patch >> series >>>>> do not contain the patch that updates the Doxygen manual. >>>>> >> ------------------------------------------------------------------------------ >>>> Want fast and easy access to all the code in your enterprise? 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