From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <musl-return-20761-ml=inbox.vuxu.org@lists.openwall.com>
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org
X-Spam-Level: 
X-Spam-Status: No, score=-3.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H4,
	RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4
Received: from second.openwall.net (second.openwall.net [193.110.157.125])
	by inbox.vuxu.org (Postfix) with SMTP id 8FA94217CB
	for <ml@inbox.vuxu.org>; Mon, 25 Mar 2024 21:31:04 +0100 (CET)
Received: (qmail 20152 invoked by uid 550); 25 Mar 2024 20:26:18 -0000
Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm
Precedence: bulk
List-Post: <mailto:musl@lists.openwall.com>
List-Help: <mailto:musl-help@lists.openwall.com>
List-Unsubscribe: <mailto:musl-unsubscribe@lists.openwall.com>
List-Subscribe: <mailto:musl-subscribe@lists.openwall.com>
List-ID: <musl.lists.openwall.com>
Reply-To: musl@lists.openwall.com
Received: (qmail 20110 invoked from network); 25 Mar 2024 20:26:17 -0000
Date: Mon, 25 Mar 2024 16:31:10 -0400
From: Rich Felker <dalias@libc.org>
To: Alexander Weps <exander77@pm.me>
Cc: musl@lists.openwall.com
Message-ID: <20240325203110.GK4163@brightrain.aerifal.cx>
References: <20240325131318.GD4163@brightrain.aerifal.cx>
 <DOttmdFY87-a4z0bN1aqXHkTKuUqDzsCIyAf0FG9Q9n6KyvPxeThCocJG3R-piziR3eQKONiexvVATdGWjNR3QokLW0ndRHoEEsqegTF-eA=@pm.me>
 <20240325134252.GE4163@brightrain.aerifal.cx>
 <20240325180208.GF4163@brightrain.aerifal.cx>
 <UR0Vya1hmBXvuPCcXsD_bEdmjRIYSZ8dbdt3ivdZxfdLASyfvp9ffpD7QPHLad2ZsOGQExkFKdmx6plvq0_eJPhY_PiGHd8Fv1-kUy_ToEg=@pm.me>
 <20240325185339.GG4163@brightrain.aerifal.cx>
 <4-8Ne4x6ZXfJmyaJ2YBFpLfCYySv9--JLQJl9OcSwaKyCashDhJXsqAPuh7G8QYwQpn2JnjUJxfZX8t9Fo101Mg_6rwb_MpmbRhFRUpYoz8=@pm.me>
 <20240325193813.GH4163@brightrain.aerifal.cx>
 <ie3F7g6_-Fn28QyD_UScBzjbuevdNW617HDFAbioKJf9mQx7XWpihGee6fV9XXPwPZiLEIb2VFonXf4wAL5Wd_trm_vKZsO7fg40L6Z5dhk=@pm.me>
 <20240325202329.GJ4163@brightrain.aerifal.cx>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="krsqJi1PDCheOQxO"
Content-Disposition: inline
In-Reply-To: <20240325202329.GJ4163@brightrain.aerifal.cx>
User-Agent: Mutt/1.5.21 (2010-09-15)
Subject: Re: [musl] Broken mktime calculations when crossing DST boundary


--krsqJi1PDCheOQxO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Mon, Mar 25, 2024 at 04:23:29PM -0400, Rich Felker wrote:
> > Also, can you share the whole code, you did some changes and I don't
> > reproduce the result. Which sample it is based on?
> 
> https://www.openwall.com/lists/musl/2024/03/25/11
> 
> The only change I made was tm_isdst=1 (you already had tm_mday=31
> there). I'll attach the file anyway though.

Forgot to attach. Here it is.

--krsqJi1PDCheOQxO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="test10.c"

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void test10()
{
    time_t t = 0;
    struct tm tm = {0};
    char buf[64];

    tm.tm_year = 2011 - 1900;
    tm.tm_mon = 12 - 1;
    tm.tm_mday = 31; // <-- here is the change
    tm.tm_hour = 0;
    tm.tm_min = 0;
    tm.tm_sec = 0;
    tm.tm_isdst = 1;

    strftime(buf, sizeof buf, "%F %T %Z", &tm);
    printf("before: %s %ld\n", buf, t);

    t = mktime(&tm);

    strftime(buf, sizeof buf, "%F %T %Z", &tm);
    printf("after1: %s %ld\n", buf, t);

    tm.tm_mday -= 1;
    t = mktime(&tm);

    strftime(buf, sizeof buf, "%F %T %Z", &tm);
    printf("after2: %s %ld\n", buf, t);

    tm.tm_mday += 1;
    t = mktime(&tm);

    strftime(buf, sizeof buf, "%F %T %Z", &tm);
    printf("after3: %s %ld\n", buf, t);
}

int main(int argc, char *argv[])
{
    test10();
    return 0;
}

--krsqJi1PDCheOQxO--