Date: Wed, 4 Jul 2012 21:45:54 +0100 From: Attilio Rao <attilio@freebsd.org> To: David Chisnall <theraven@freebsd.org> Cc: src-committers@freebsd.org, Pawel Jakub Dawidek <pjd@freebsd.org>, svn-src-all@freebsd.org, Konstantin Belousov <kostikbel@gmail.com>, svn-src-head@freebsd.org, Andrey Chernov <ache@freebsd.org>, markm@freebsd.org Subject: Re: svn commit: r238118 - head/lib/libc/gen Message-ID: <CAJ-FndAGgkgi5W3LqgMkeK9AquQ=1RhhYcj4jnLmuRg2EwVuqA@mail.gmail.com> In-Reply-To: <8344944B-1CEE-4CAD-96FB-EC5A743F6909@FreeBSD.org> References: <201207041951.q64JpPXu029310@svn.freebsd.org> <20120704200220.GM2337@deviant.kiev.zoral.com.ua> <20120704203239.GA42326@vniz.net> <8344944B-1CEE-4CAD-96FB-EC5A743F6909@FreeBSD.org>
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2012/7/4 David Chisnall <theraven@freebsd.org>: > On 4 Jul 2012, at 21:32, Andrey Chernov wrote: > >> 1) /dev/urandom may not exist in jails/sandboxes while sysctls (or old w= ay >> initialization) always exists. > > From the perspective of Capsicum sandboxes, a device node is better than = a sysctl. The kernel must hard-code policy about which sysctls are permitt= ed, but access to file descriptors is decided on a per-sandbox basis and is= configurable by the user. The same applies to jails, although it's slight= ly more effort to make device nodes appear inside a jail. Also don't understimate the locking factor here. I recall that at some point /dev/random was introducing some scalability penalty on php (maybe related to the suhosin patch) until kib made shared lookups available on devfs. IIRC, sysctls are still Giant locked. Attilio --=20 Peace can only be achieved by understanding - A. Einstein
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