From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_MSPIKE_H2,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 31371 invoked from network); 17 Aug 2022 22:39:09 -0000 Received: from second.openwall.net (193.110.157.125) by inbox.vuxu.org with ESMTPUTF8; 17 Aug 2022 22:39:09 -0000 Received: (qmail 11585 invoked by uid 550); 17 Aug 2022 22:39:06 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 11551 invoked from network); 17 Aug 2022 22:39:05 -0000 Date: Wed, 17 Aug 2022 18:38:52 -0400 From: Rich Felker To: musl@lists.openwall.com Message-ID: <20220817223848.GE7074@brightrain.aerifal.cx> References: <6bac31d90ea71e6151f950f1cc5e6171@anonymousemail.me> <20220817151131.GB7074@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220817151131.GB7074@brightrain.aerifal.cx> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] Broken freopen() does not reset fwide() On Wed, Aug 17, 2022 at 11:11:31AM -0400, Rich Felker wrote: > On Tue, Aug 16, 2022 at 06:33:35PM +0000, Anonymousemail wrote: > > Powered by Anonymousemail → [1]Join Us! > > > > I'm using musl based distribution. > > The official example from https://en.cppreference.com/w/c/io/fwide is > > malfunctioning, musl does not reset the fwide(), returns -1 (meaning BYTE > > oriented). > > > > Output from example on musl: > > 1) A newly opened stream has no orientation. > > no orientation > > 2) Establish byte orientation. > > narrow orientation > > narrow character read '#' > > wide character read 'i' > > 3) Only freopen() can reset stream orientation. > > 4) A reopened stream has no orientation. > > narrow orientation <- problem detected here, should say "no > > orientation" > > 5) Establish wide orientation. > > narrow orientation > > narrow character read '#' > > wide character read 'i' > > > > Another simple example to reproduce the issue.: > > #include > > #include > > #include // for EXIT_SUCCESS > > #include > > > > int main() { > > enum { narrow = -1, query = 0, wide = 1 }; > > FILE* test = fopen("test.bin", "r"); > > if(!test) { > > puts("You need to have test.bin file."); > > abort(); > > } > > // establish NARROW orientation > > fwide(test, narrow); > > // reopen to reset, broken on musl > > freopen("test.bin", "r", test); > > assert(fwide(test, query) == 0); // will fail on musl > > // CLEANUP > > fclose(test); > > // Exit the program > > return EXIT_SUCCESS; > > } > > > > ----- > > Save as main.c, run with > > cc main.c > > echo test >test.bin > > ../a.out > > > > Will output > > Assertion failed: fwide(test, query) == 0 (main2.c: main: 17) > > Aborted > > Indeed this looks like an oversight. I'll need to look at what it will > take to fix it. Naively, just f->wide = 0 before successful return in > freopen seems ok, but probably also f->locale needs to be set to 0 to > reset the encoding rule, and it might be necessary to null out some > buffer pointers to force future calls to stdio functions to reprobe > the width. > > Thanks for the report. > > BTW is there a way you can fix the mailer you're using? The plain text > version of your mail was not plain text, but was littered with html > entities (  etc.) making it unreadable, so I rendered the html > version to text in order to be able to reply. OK, fflush took care of the buffer pointers already, so just setting f->mode and f->locale to 0 should be fine. I'll commit a fix. Rich