From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 8EC9B138202 for ; Fri, 11 Oct 2013 22:10:14 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 22665E09F1; Fri, 11 Oct 2013 22:10:12 +0000 (UTC) Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) (using TLSv1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 8DFE4E0AEE for ; Fri, 11 Oct 2013 22:10:11 +0000 (UTC) Received: from work-Thinkpad.mattst88.com (unknown [108.161.26.224]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: mattst88) by smtp.gentoo.org (Postfix) with ESMTPSA id B500833EFEA; Fri, 11 Oct 2013 22:10:10 +0000 (UTC) From: Matt Turner To: gentoo-catalyst@lists.gentoo.org Cc: "W. Trevor King" Subject: [gentoo-catalyst] [PATCH 3/3] livecdfs-update.sh: Use `bash --login` to spawn startx Date: Fri, 11 Oct 2013 15:09:42 -0700 Message-Id: <1381529382-18766-3-git-send-email-mattst88@gentoo.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1381529382-18766-1-git-send-email-mattst88@gentoo.org> References: <1381529382-18766-1-git-send-email-mattst88@gentoo.org> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-catalyst@lists.gentoo.org Reply-to: gentoo-catalyst@lists.gentoo.org X-Archives-Salt: c683725d-7f2e-4c5f-9174-b2b416680a85 X-Archives-Hash: 8df6441b777c58049bc36b3bc83100a4 From: "W. Trevor King" Starting a "login" version of Bash via `su` is tricky. The naive: su - ${first_user} -c startx fails because `su - ...` clears a number of environment variables (so the prefixed `source /etc/profile` doesn't accomplish anything), but Bash isn't started with the `--login` option, so it doesn't source /etc/profile internally. From bash(1): A login shell is one whose first character of argument zero is a -, or one started with the --login option. ... An interactive shell is one started without non-option arguments and without the -c option whose standard input and error are both connected to terminals (as determined by isatty(3)), or one started with the -i option... ... When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior. In order to get the login-style profile loading with a non-interactive `su` invocation, you need to use something like: echo "${command}" | su - "${user}" This starts a login shell and pipes the command in via stdin, which seems to fake Bash into thinking its running from an interactive terminal. Not the most elegant, but the other implementations I can think of are even worse: su - "${user}" -c "bash --login -c ${command}" su - "${user}" -c 'source /etc/profile && (source .bash_profile || ...) && ${command}" The old expression was broken anyway due to unescaped ampersands in the sed expression. From sed(1): s/regexp/replacement/ Attempt to match regexp against the pattern space. If successful, replace that portion matched with replacement. The replacement may contain the special character & to refer to that portion of the pattern space which matched, and the special escapes \1 through \9 to refer to the corresponding matching sub-expressions in the regexp. This means that the old expression (with unescaped ampersands) lead to: source /etc/profile ##STARTX##STARTX su - ${first_user} -c startx with ${first_user} expanded. This commented out startx, so it was never run. Reviewed-by: Matt Turner --- targets/support/livecdfs-update.sh | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/targets/support/livecdfs-update.sh b/targets/support/livecdfs-update.sh index f8eb425..2b41f9d 100644 --- a/targets/support/livecdfs-update.sh +++ b/targets/support/livecdfs-update.sh @@ -377,9 +377,7 @@ esac # We want the first user to be used when auto-starting X if [ -e /etc/startx ] then - sed -i \ - "s:##STARTX:source /etc/profile && su - ${first_user} -c startx:" \ - /root/.bashrc + sed -i "s:##STARTX:echo startx | su - '${first_user}':" /root/.bashrc fi if [ -e /lib/rcscripts/addons/udev-start.sh ] -- 1.8.3.2