ports/167108: www/uwsgi: rc script doesn't work on startup when profiles are used

[Michael Gmelin]

>Number:         167108
>Category:       ports
>Synopsis:       www/uwsgi: rc script doesn't work on startup when profiles are used
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Apr 19 19:30:10 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Michael Gmelin
>Release:        9.0-RELEASE
>Organization:
Grem Equity GmbH
>Environment:
FreeBSD server 9.0-RELEASE FreeBSD 9.0-RELEASE #0: Fri Feb 24 21:08:08 UTC 2012     root at server:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
/usr/local/etc/rc.d/uwsgi does re-invoke itself when processing profiles and relies on $0 to determine its own location. This works ok on a running system where/usr/local/etc/rc.d/uwsgi is invoked directly, but does not work on system startup, when $0 equals /etc/rc. The output in this case is:

..
Processing uwsgi profile: myprofile
/usr/local/etc/rc.d/uwsgi: /etc/rc: Permission denied
..

This happens because rc.subr's run_rc_script function sources rc scripts to execute them, see man 8 rc.subr on that function:
..
           4.   If the rc.conf(5) variable rc_fast_and_loose is empty, source
                file in a sub shell, otherwise source file into the current
                shell.
..

>How-To-Repeat:
An easy way to test the problem without rebooting is to create a script that simulates the behavior of /etc/rc (and /etc/rc.subr):

echo "(set start ; . /usr/local/etc/rc.d/uwsgi)" >/tmp/rcsimul

cd /usr/ports/www/uwsgi
make -DBATCH install clean
echo 'uwsgi_enabled="YES"' >> /etc/rc.conf
echo 'uwsgi_profiles="myprofile"' >> /etc/rc.conf
echo 'uwsgi_myprofile_flags="doesntmatter"' >> /etc/rc.conf
/bin/sh /tmp/rcsimul

Expected output:
Processing uwsgi profile: myprofile
/usr/local/etc/rc.d/uwsgi: /tmp/rcsimul: Permission denied

Alternatively reboot the machine and check /var/log/messages or dmesg.

>Fix:
As a workaround, apply the following patch which replaces $0 with the exact path to the uwsgi rc script. 

--- /usr/local/etc/rc.d/uwsgi~	2012-04-19 18:48:25.000000000 +0000
+++ /usr/local/etc/rc.d/uwsgi	2012-04-19 18:48:25.000000000 +0000
@@ -80,7 +80,7 @@
 	elif [ -n "$1" ]; then
 		for profile in ${uwsgi_profiles}; do
 	            echo "Processing ${name} profile: ${profile}"
-	            $0 $1 ${profile}
+	            /usr/local/etc/rc.d/uwsgi $1 ${profile}
 	        done
 	        exit 0
 	fi

Refactoring the script so that re-invoking itself won't be required would be a better (but more elaborate) fix.


>Release-Note:
>Audit-Trail:
>Unformatted: