Bug 13625 – distcc + ccache failure: failed to create /root/.ccache (Permission Denied)

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Eric Andresen 2003-01-10 03:55:50 UTC]

I ran into this earlier when upgrading a few packages, but when using distcc
through ccache, builds would fail with an error along the lines of "ccache:
failed to create /root/.ccache (Permission Denied)". To test, I used two of my
machines, both running distcc-0.15 (and 0.14-r1 as well, to test) and
ccache-1.9-r2. Using the /etc/init.d/distcc script installed with the emerge,
the distccd daemon is chuid'd to the user 'nobody', but the environment variable
HOME lingers, and ccache apparently uses it to create ~/.ccache/stats, even when
run over distcc. This in practice causes the distccd daemon run as 'nobody' with
the HOME environment of root to try to create /root/.ccache/stats. 

A solution was simple enough once testing it was the HOME environment causing
the problem: append HOME="/tmp" to the front of the distccd init.d script. The
diff is as follows:

----BEGIN-----
--- /etc/init.d/distccd	2003-01-10 02:35:29.000000000 -0700
+++ /etc/init.d/._cfg0000_distccd	2003-01-10 02:44:39.000000000 -0700
@@ -7,7 +7,7 @@
 start() {
 	rm -rf /var/tmp/distccd.pid
 	ebegin "Starting distccd"
-	HOME="/tmp" start-stop-daemon --start --quiet --startas /usr/bin/distccd \
+	start-stop-daemon --start --quiet --startas /usr/bin/distccd \
 		-c nobody --pidfile /var/tmp/distccd.pid \
 		-- --pid-file /var/tmp/distccd.pid
 	eend $? "Failed to Start distccd"

-----END-----

[Comment 1 Brad Cowan (RETIRED) 2003-01-11 21:08:32 UTC]

Here's the problem I'm having with this....ccache doesn't have anything to do
with distccd afaik...the cache is parsed and headers etc and sent via distcc on
the machine doing the compiling. Distccd is the daemon on the "helper machines"
and doesn't read ccache. Distcc is run as root on the compiling box, only
distccd on the helper machines is setuid 'nobody'.

[Comment 2 Eric Andresen 2003-01-12 00:53:50 UTC]

What was happening was that ccache was somehow being called on the remote
distccd host, even though it wasn't storing any objects. So when ccache was
called, it would try to create ~/.ccache, which was $HOME/.ccache

The reason for ccache being called is because /usr/bin/ccache was listed in the
PATH env before /usr/i686-pc-linux-gnu/gcc-bin/3.2 when distccd was started, and
thus inherited. I suppose the best method to get around this would be to not set
the HOME env, but rather set the PATH to be strictly
/usr/i686-pc-linux-gnu/gcc-bin/3.2

So this would be the result to ensure distccd was started with only that path..

--- distccd.old 2003-01-11 23:50:55.000000000 -0700
+++ distccd     2003-01-11 23:48:40.000000000 -0700
@@ -7,7 +7,7 @@
 start() {
        rm -rf /var/tmp/distccd.pid
        ebegin "Starting distccd"
-       start-stop-daemon --start --quiet --startas /usr/bin/distccd \
+       PATH="/usr/i686-pc-linux-gnu/gcc-bin/3.2" /sbin/start-stop-daemon
--start --quiet --startas /usr/bin/distccd \
                -c nobody --pidfile /var/tmp/distccd.pid \
                -- --pid-file /var/tmp/distccd.pid
        eend $? "Failed to Start distccd"

[Comment 3 Brad Cowan (RETIRED) 2003-01-15 22:54:36 UTC]

added your latest init script to distcc-1.0