[PATCH v5 09/11] tools/xenstored: Rename dom0_domid to store_domid

[Jason Andryuk <jason.andryuk@xxxxxxx>]

The dom0_domid variable is misnamed and conflates purposes.  If we have
xenstored running in a Linux domain that is not dom0, this variable
controls the lookup of /proc/xen/xsd_kva and the event channel.

Rename to store_domid to better show its purpose.

One implication of this change is that the xenstore domain is not
privileged by virtue of considering store_domid as privileged.

domain_is_unprivileged() removes the dom0_domid/store_domid check, so
xenstore domain is no longer considered privileged.

onearg_domain() is updated to return EINVAL for store_domid or priv_domid
to maintain the ability to call XS_RESUME.

xenbus_master_domid() is removed with store_domid being used instead.

Add a description of the -m/--master-domid options while
doing this.

Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
v5:
Remove xenbus_master_domid()
domain_is_unprivileged() drop dom0/store_domid.
XS_RESUME/onearg_domain() check store_domid || priv_domid
---
 tools/xenstored/core.c   |  9 ++++++---
 tools/xenstored/core.h   |  6 ++----
 tools/xenstored/domain.c | 10 +++++-----
 tools/xenstored/posix.c  |  4 ++--
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/tools/xenstored/core.c b/tools/xenstored/core.c
index 098958f611..f407bec4b9 100644
--- a/tools/xenstored/core.c
+++ b/tools/xenstored/core.c
@@ -2536,7 +2536,10 @@ static void usage(void)
 "                          allowed timeout candidates are:\n"
 "                          watch-event: time a watch-event is kept pending\n"
 "  -K, --keep-orphans      don't delete nodes owned by a domain when the\n"
-"                          domain is deleted (this is a security risk!)\n");
+"                          domain is deleted (this is a security risk!)\n"
+"  -m, --master-domid      specify the domid of the domain where xenstored\n"
+"                          is running.  defaults to 0\n"
+);
 }
 
 
@@ -2564,7 +2567,7 @@ static struct option options[] = {
 #endif
        { NULL, 0, NULL, 0 } };
 
-int dom0_domid = DOMID_INVALID;
+int store_domid = DOMID_INVALID;
 int dom0_event = 0;
 int priv_domid = DOMID_INVALID;
 domid_t stub_domid = DOMID_INVALID;
@@ -2733,7 +2736,7 @@ int main(int argc, char *argv[])
                        dom0_event = get_optval_uint(optarg);
                        break;
                case 'm':
-                       dom0_domid = get_optval_uint(optarg);
+                       store_domid = get_optval_uint(optarg);
                        break;
                case 'p':
                        priv_domid = get_optval_uint(optarg);
diff --git a/tools/xenstored/core.h b/tools/xenstored/core.h
index 877b1e1103..949b812f90 100644
--- a/tools/xenstored/core.h
+++ b/tools/xenstored/core.h
@@ -364,7 +364,7 @@ do {                                                \
                trace("tdb: " __VA_ARGS__);     \
 } while (0)
 
-extern int dom0_domid;
+extern int store_domid;
 extern int dom0_event;
 extern int priv_domid;
 extern domid_t stub_domid;
@@ -381,11 +381,9 @@ uint64_t get_now_msec(void);
 void *xenbus_map(void);
 void unmap_xenbus(void *interface);
 
-static inline int xenbus_master_domid(void) { return dom0_domid; }
-
 static inline bool domid_is_unprivileged(unsigned int domid)
 {
-       return domid != dom0_domid && domid != priv_domid;
+       return domid != priv_domid;
 }
 
 static inline bool domain_is_unprivileged(const struct connection *conn)
diff --git a/tools/xenstored/domain.c b/tools/xenstored/domain.c
index 94cbe81ca5..2f79db26df 100644
--- a/tools/xenstored/domain.c
+++ b/tools/xenstored/domain.c
@@ -503,7 +503,7 @@ static const struct interface_funcs domain_funcs = {
 
 static void *map_interface(domid_t domid)
 {
-       if (domid == xenbus_master_domid())
+       if (domid == store_domid)
                return xenbus_map();
 
 #ifdef __MINIOS__
@@ -518,7 +518,7 @@ static void *map_interface(domid_t domid)
 
 static void unmap_interface(domid_t domid, void *interface)
 {
-       if (domid == xenbus_master_domid())
+       if (domid == store_domid)
                unmap_xenbus(interface);
        else if (domid != stub_domid)
                xengnttab_unmap(*xgt_handle, interface, 1);
@@ -1144,7 +1144,7 @@ static struct domain *onearg_domain(struct connection 
*conn,
                return ERR_PTR(-EINVAL);
 
        domid = atoi(domid_str);
-       if (domid == dom0_domid)
+       if (domid == store_domid || domid == priv_domid)
                return ERR_PTR(-EINVAL);
 
        return find_connected_domain(domid);
@@ -1307,12 +1307,12 @@ void init_domains(void)
                         * have 1 domain.  stubdom there will be dom0 and dom1,
                         * so this will take the second for stubdom.
                         */
-                       dom0_domid = domid;
+                       store_domid = domid;
                }
        }
 
        if (priv_domid == DOMID_INVALID)
-               priv_domid = dom0_domid;
+               priv_domid = store_domid;
 
        if (priv_domid == DOMID_INVALID)
                barf("Could not determine xenstore domid\n");
diff --git a/tools/xenstored/posix.c b/tools/xenstored/posix.c
index d850dc0da9..e8bb975115 100644
--- a/tools/xenstored/posix.c
+++ b/tools/xenstored/posix.c
@@ -174,7 +174,7 @@ static evtchn_port_t get_xenbus_evtchn(void)
  */
 evtchn_port_t get_domain_evtchn(unsigned int domid)
 {
-       if (domid == xenbus_master_domid())
+       if (domid == store_domid)
                return get_xenbus_evtchn();
 
        return 0;
@@ -280,7 +280,7 @@ static void accept_connection(int sock)
        conn = new_connection(&socket_funcs);
        if (conn) {
                conn->fd = fd;
-               conn->id = dom0_domid;
+               conn->id = store_domid;
        } else
                close(fd);
 }
-- 
2.50.1