From owner-freebsd-current@FreeBSD.ORG Thu Oct 18 08:53:50 2007 Return-Path: Delivered-To: freebsd-current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4BFE216A419 for ; Thu, 18 Oct 2007 08:53:50 +0000 (UTC) (envelope-from matrix@itlegion.ru) Received: from corpmail.itlegion.ru (corpmail.itlegion.ru [84.21.226.211]) by mx1.freebsd.org (Postfix) with SMTP id 8789613C469 for ; Thu, 18 Oct 2007 08:53:49 +0000 (UTC) (envelope-from matrix@itlegion.ru) Received: (qmail 56988 invoked from network); 18 Oct 2007 12:53:47 +0400 Received: from unknown (HELO Artem) (192.168.0.12) by 84.21.226.211 with SMTP; 18 Oct 2007 12:53:47 +0400 X-AntiVirus: Checked by Dr.Web [version: 4.44, engine: 4.44.0.09170, virus records: 249974, updated: 18.10.2007] Message-ID: <013c01c81164$628def90$0c00a8c0@Artem> From: "Artem Kuchin" To: "David Xu" References: <00bd01c810ec$10371230$0c00a8c0@Artem> <47171988.7040706@freebsd.org> Date: Thu, 18 Oct 2007 12:53:40 +0400 Organization: IT Legion MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="ISO-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 Cc: freebsd-current@FreeBSD.org Subject: Re: Broken su in current - trying to fix myself, help needed! X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Oct 2007 08:53:50 -0000 David Xu wrote: > Artem Kuchin wrote: >> Hello! >> >> I really not at all good at any kind of system programming >> in FreeBSD or Un*x, but since my contacts with last commited >> of su could not be establish i decided to look at it myself. >> >> If you don't know what is the problem i'll describe it shortly: >> >> if you try to run a very simple perl script: >> >> #!/usr/bin/perl >> $com="/usr/bin/su root -c 'echo heck'"; >> system($com); >> print "done!\n"; >> >> it will print heck >> >> and then >> >> Suspended (tty output) >> >> and will hang in memory untill you type >> fg >> >> then you get >> >> done! >> >> >> I am working in csh, but i tested it in sh - result is >> the same. FreeBSD version is 7-PRERELEASE. >> >> >> So, I fetched su v. 1.76 from 6.2-STABLE and compiled it - it works >> like a charm. SO, i decided to figure what fails in 1.86. >> >> There are such like in the default: dection of switch >> >> child_pgrp = getpgid(child_pid); >> if (tcgetpgrp(STDERR_FILENO) == child_pgrp) >> tcsetpgrp(STDERR_FILENO, getpgrp()); >> >> >> The problem is here. >> getpgid(child_pid) simply fails with errno 3 (process doesn't exist) >> and tcgetpgrp(STDERR_FILENO) return 100000 (can it be THAT high? i >> though it is only in 0-65535 range). >> >> The weird thing is that if i just comment out those lines like this >> >> /* child_pgrp = getpgid(child_pid); >> if (tcgetpgrp(STDERR_FILENO) == child_pgrp) */ >> tcsetpgrp(STDERR_FILENO, getpgrp()); >> >> su starts working again just fine. >> >> Any idea why getpgid fails and why tcgetpgrp return 100000 (always >> the same number)? What will brak if i leave these lines commented? >> >> -- >> Regards, >> Artem > > file su.c, line 472 may be incorrect since line 456 is a while loop > which only > exits if child process is exited. just remove line 472 and 473 to see > if problem > is fixed. Let me quote myself: The weird thing is that if i just comment out those lines like this /* child_pgrp = getpgid(child_pid); if (tcgetpgrp(STDERR_FILENO) == child_pgrp) */ tcsetpgrp(STDERR_FILENO, getpgrp()); su starts working again just fine.