Hi Albert, Actually the second issue relating to the variable last_change not being a static is NOT specifically related to how dnsmasq handles time. Without the static definition of last_change, the "if(difftime(statbuf.st_mtime, last_change)" ALWAYS evaluates to > 0, which is not what the code was intended to do. I believe the intent of this code is to avoid unnecessary calls to reload_servers()... in other words, if there has been no time elapsed since we last reloaded the servers, then we shouldn't do it again. The result of the difftime() in this case should be the number of seconds since dnsmasq last did the reload_servers. With the broken code, the difftime() ALWAYS resulted in the number of seconds between time 0 (the initialized value of last_change) and the timestamp on the /etc/resolv.conf file... and consequently, this would ALWAYS result in a call to reload_servers(), whether it was needed or not. I don't consider this a major issue.. with the broken code, it just means that there may be an extra reload_servers done here and there.
The issue with the current time being potentially less than current timestamps in dnsmasq() is an issue in dnsmasq in general and comes into play whenever difftime() is used to determine elapsed time. In most uses of difftime, the code assumes current time is greater than any cached time; when current time is less than the cached timestamp, the code has issues. As I pointed out previously, I saw only one use of difftime() where the code actually took into consideration that the current time might be less than cached timestamp... all other uses of difftime MAY have issues when result of difftime is negative. With the impact of ntp, it is possible that the time goes backwards on the router, such as might happen with daylight savings time in the fall, when clocks are adjusted backwards in the USA by one hour... or when the clock on the router is not right and ntp corrects it. I hope this clarifies what I was trying to say. John __________________________________________________________________ Confidential This e-mail and any files transmitted with it are the property of Belkin International, Inc. and/or its affiliates, are confidential, and are intended solely for the use of the individual or entity to whom this e-mail is addressed. If you are not one of the named recipients or otherwise have reason to believe that you have received this e-mail in error, please notify the sender and delete this message immediately from your computer. Any other use, retention, dissemination, forwarding, printing or copying of this e-mail is strictly prohibited. Pour la version française: http://www.belkin.com/email-notice/French.html Für die deutsche Übersetzung: http://www.belkin.com/email-notice/German.html __________________________________________________________________ _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
