From 9fac502920a648d82e21b207989bfc3c00fbdebc Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 14 Aug 2020 18:56:54 +0200 Subject: nspawn,pid1: pass "inaccessible" nodes from cntr mgr to pid1 payload via /run/host Let's make /run/host the sole place we pass stuff from host to container in and place the "inaccessible" nodes in /run/host too. In contrast to the previous two commits this is a minor compat break, but not a relevant one I think. Previously the container manager would place these nodes in /run/systemd/inaccessible/ and that's where PID 1 in the container would try to add them too when missing. Container manager and PID 1 in the container would thus manage the same dir together. With this change the container manager now passes an immutable directory to the container and leaves /run/systemd entirely untouched, and managed exclusively by PID 1 inside the container, which is nice to have clear separation on who manages what. In order to make sure systemd then usses the /run/host/inaccesible/ nodes this commit changes PID 1 to look for that dir and if it exists will symlink it to /run/systemd/inaccessible. Now, this will work fine if new nspawn and new pid 1 in the container work together. as then the symlink is created and the difference between the two dirs won't matter. For the case where an old nspawn invokes a new PID 1: in this case things work as they always worked: the dir is managed together. For the case where different container manager invokes a new PID 1: in this case the nodes aren't typically passed in, and PID 1 in the container will try to create them and will likely fail partially (though gracefully) when trying to create char/block device nodes. THis is fine though as there are fallbacks in place for that case. For the case where a new nspawn invokes an old PID1: this is were the (minor) incompatibily happens: in this case new nspawn will place the nodes in the /run/host/inaccessible/ subdir, but the PID 1 in the container won't look for them there. Since the nodes are also not pre-created in /run/systed/inaccessible/ PID 1 will try to create them there as if a different container manager sets them up. This is of course not sexy, but is not a total loss, since as mentioned fallbacks are in place anyway. Hence I think it's OK to accept this minor incompatibility. --- src/test/test-dev-setup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'src/test/test-dev-setup.c') diff --git a/src/test/test-dev-setup.c b/src/test/test-dev-setup.c index 038484e475..11196cd4d6 100644 --- a/src/test/test-dev-setup.c +++ b/src/test/test-dev-setup.c @@ -3,6 +3,7 @@ #include "capability-util.h" #include "dev-setup.h" #include "fs-util.h" +#include "mkdir.h" #include "path-util.h" #include "rm-rf.h" #include "tmpfile-util.h" @@ -17,8 +18,8 @@ int main(int argc, char *argv[]) { assert_se(mkdtemp_malloc("/tmp/test-dev-setupXXXXXX", &p) >= 0); - f = prefix_roota(p, "/run"); - assert_se(mkdir(f, 0755) >= 0); + f = prefix_roota(p, "/run/systemd"); + assert_se(mkdir_p(f, 0755) >= 0); assert_se(make_inaccessible_nodes(f, 1, 1) >= 0); -- cgit v1.2.3