Date: Tue, 18 May 2004 12:03:16 +0400 (MSD) From: Alex Semenyaka <alex@semenyaka.ru> To: FreeBSD-gnats-submit@FreeBSD.org Subject: conf/66791: Old dev.db leads to the wrong program behaviour (4.x specific) Message-ID: <200405180803.i4I83Gjw027569@qqmore.rinet.ru.> Resent-Message-ID: <200405180810.i4I8ANkU016300@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 66791 >Category: conf >Synopsis: Old dev.db leads to the wrong program behaviour (4.x specific) >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Tue May 18 01:10:23 PDT 2004 >Closed-Date: >Last-Modified: >Originator: Alex Semenyaka >Release: FreeBSD 4.10-PRERELEASE i386 >Organization: no >Environment: System: FreeBSD qqmore.rinet.ru 4.10-PRERELEASE FreeBSD 4.10-PRERELEASE #7: Sat May 8 18:33:04 MSD 2004 root@qqmore.rinet.ru:/.ad4s1a/usr/src/sys/compile/BOOJUM i386 >Description: If the set of devices has been changed the dev.db need to be rebuilt under 4.x, otherwise devname() and ttyname() can give the wrong results. They rely upon the content of /var/run/dev.db that can be obsoleted if new devices were created. That file is rebuilding during the start-up process. However the content of /dev can be changed without reboot, on the fly. Moreover, /dev/MAKEDEV can be changed during the system update but run just after the reboot so /var/run/dev.db will not be rebuilt. The problem caused by that are pretty rare but sometimes they can happened. >How-To-Repeat: Exchange major or minor version of two devices, open first of them with open(2) and print the result of devname(3) for the descriptor. It is absolutely non-typical but simple to illustrate the point. >Fix: Do not rely on the reboot, rebuild dev.db directly from MAKEDEV. To do so, add to the very end of /dev/MAKEDEV the string /sbin/dev_mkdb Also pretty useful would be adding the reference to the dev_mkdb manual page to the MAKEDEV manual page. To do it, apply the following patch to both i386/MAKEDEV.8 and alpha/MAKEDEV.8: --- MAKEDEV.8.old Tue May 18 11:58:09 2004 +++ MAKEDEV.8 Tue May 18 11:58:22 2004 @@ -116,2 +116,3 @@ .Xr config 8 , -.Xr mknod 8 +.Xr mknod 8 , +.Xr dev_mkdb 8 >Release-Note: >Audit-Trail: >Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200405180803.i4I83Gjw027569>