xenstored: don't use xenevtchn_fdopen() in stubdom

When running in a stubdom environment xenevtchn_fdopen() won't work,
as any file descriptor state is lost across kexec().

Use a wrapper to replace the call of xenevtchn_fdopen() with the
really needed xenevtchn_open() when running on top of Mini-OS.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>

tools/xenstored/core.h

@@ -29,6 +29,7 @@
 #include <stdint.h>
 #include <time.h>
 #include <errno.h>
+#include <xenevtchn.h>
 
 #include "xenstore_lib.h"
 #include "xenstore_state.h"
@@ -405,6 +406,8 @@ void handle_special_fds(void);
 int get_socket_fd(void);
 void set_socket_fd(int fd);
 
+xenevtchn_handle *evtchn_fdopen(int fd);
+
 #ifdef __MINIOS__
 void mount_9pfs(void);
 #endif

tools/xenstored/domain.c

@@ -1396,7 +1396,7 @@ void domain_init(int evtfd)
 	if (evtfd < 0)
 		xce_handle = xenevtchn_open(NULL, XENEVTCHN_NO_CLOEXEC);
 	else
-		xce_handle = xenevtchn_fdopen(NULL, evtfd, 0);
+		xce_handle = evtchn_fdopen(evtfd);
 
 	if (xce_handle == NULL)
 		barf_perror("Failed to open evtchn device");

tools/xenstored/minios.c

@@ -85,6 +85,11 @@ void set_socket_fd(int fd)
 {
 }
 
+xenevtchn_handle *evtchn_fdopen(int fd)
+{
+	return xenevtchn_open(NULL, XENEVTCHN_NO_CLOEXEC);
+}
+
 static void mount_thread(void *p)
 {
 	xenbus_event_queue events = NULL;

tools/xenstored/posix.c

@@ -408,6 +408,11 @@ void set_socket_fd(int fd)
 	sock = fd;
 }
 
+xenevtchn_handle *evtchn_fdopen(int fd)
+{
+	return xenevtchn_fdopen(NULL, fd, 0);
+}
+
 const char *xenstore_rundir(void)
 {
 	return xenstore_daemon_rundir();