From owner-cvs-all@FreeBSD.ORG Wed Jun 18 01:43:10 2008 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 55AA1106566B; Wed, 18 Jun 2008 01:43:10 +0000 (UTC) (envelope-from davidxu@freebsd.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 3BDEC8FC13; Wed, 18 Jun 2008 01:43:10 +0000 (UTC) (envelope-from davidxu@freebsd.org) Received: from apple.my.domain (root@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.2/8.14.2) with ESMTP id m5I1h8Ok084949; Wed, 18 Jun 2008 01:43:09 GMT (envelope-from davidxu@freebsd.org) Message-ID: <4858688E.2030404@freebsd.org> Date: Wed, 18 Jun 2008 09:44:46 +0800 From: David Xu User-Agent: Thunderbird 2.0.0.9 (X11/20080612) MIME-Version: 1.0 To: Maxim Sobolev References: <200806170633.m5H6XMJH084600@repoman.freebsd.org> <20080617134828.GA30076@zim.MIT.EDU> <20080617140600.GE1176@hoeg.nl> <4857D508.8070907@FreeBSD.org> <48586652.2070204@freebsd.org> In-Reply-To: <48586652.2070204@freebsd.org> Content-Type: text/plain; charset=KOI8-U; format=flowed Content-Transfer-Encoding: 7bit Cc: Ed Schouten , src-committers@freebsd.org, cvs-all@freebsd.org, cvs-src@freebsd.org Subject: Re: cvs commit: src/include Makefile spawn.h unistd.h src/lib/libc/gen Makefile.inc Symbol.map exec.3 exec.c posix_spawn.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Jun 2008 01:43:10 -0000 David Xu wrote: > I just want to make some programs to work, since Linux and Solaris > both have it now. Doing it in kernel is OK, but I don't want to put > it into the kernel until it is necessary since kernel code can not > be swapped out. ;-) > > Doing in kernel may have advantages, for example, you may get ride > of zoombie process recycling by hacking kernel, a library version > using vfork will need parent to handle SIGCHLD and recycle zoombie > process like you use popen() and system() etcs, Oops, I rethinked it, zoombie process is not a correct point. only rtld is the problem. > another advantage > is it won't involve rtld if a symbol needs to resolved, because > vfork shares same vmspace, it might block other threads in > parent process if the child process holding a rtld's > reader lock, I don't know if writer lock will be held in child, > I guess it won't be. if the child process get killed wrongly > by someone, it might hold reader lock forever, this is the race > condition. a kernel version may have trouble if something can not > be easily done in kernel, though I didn't find the one can not > be done in kernel at present. > > Regards, > David Xu > >