[libvirt] [PATCH] Explicitly pass uml_dir argument to user-mode-linux

[Soren Hansen]

uml_dir overrides user-mode-linux's default of ~/.uml. This is needed
for a couple of different reasons:

libvirt expects this to default to virGetUserDirectory(geteuid()) +
'/.uml'. However, user-mode-linux actually uses the HOME environment
variable to determine where to look for the uml sockets, but if running
libvirtd under sudo (which I routinely do during development), $HOME is
pointing at my user's homedir, while my euid is 0, so libvirt looks in
/root.

Also (and this was my actual motivation for this patch), if HOME isn't
set at all, user-mode-linux utterly fails. Looking at the code, it seems
it's meant to emit a warning, but alas, it doesn't for some reason.
If running libvirtd from upstart, HOME is not set, so any system using
upstart will need this change.

Signed-off-by: Soren Hansen <soren at linux2go.dk>
---
 src/uml/uml_conf.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/uml/uml_conf.c b/src/uml/uml_conf.c
index 65b06c5..4906192 100644
--- a/src/uml/uml_conf.c
+++ b/src/uml/uml_conf.c
@@ -409,7 +409,7 @@ static char *umlNextArg(char *args)
  * for a given virtual machine.
  */
 int umlBuildCommandLine(virConnectPtr conn,
-                        struct uml_driver *driver ATTRIBUTE_UNUSED,
+                        struct uml_driver *driver,
                         virDomainObjPtr vm,
                         fd_set *keepfd,
                         const char ***retargv,
@@ -499,7 +499,6 @@ int umlBuildCommandLine(virConnectPtr conn,
     ADD_ENV_COPY("LD_PRELOAD");
     ADD_ENV_COPY("LD_LIBRARY_PATH");
     ADD_ENV_COPY("PATH");
-    ADD_ENV_COPY("HOME");
     ADD_ENV_COPY("USER");
     ADD_ENV_COPY("LOGNAME");
     ADD_ENV_COPY("TMPDIR");
@@ -508,6 +507,7 @@ int umlBuildCommandLine(virConnectPtr conn,
     //ADD_ARG_PAIR("con0", "fd:0,fd:1");
     ADD_ARG_PAIR("mem", memory);
     ADD_ARG_PAIR("umid", vm->def->name);
+    ADD_ARG_PAIR("uml_dir", driver->monitorDir);
 
     if (vm->def->os.root)
         ADD_ARG_PAIR("root", vm->def->os.root);
-- 
1.7.0.4