[OE-core] [PATCH 1/1] runqemu: acquire_lock() should fail when failed to open the file

[Robert Yang]

The open(self.lock, 'w') may fail when the lock is created by other
users, return false for this case to let it try other devices.

Fixed:
runqemu - INFO - Running /sbin/ip link...
runqemu - INFO - Acquiring lockfile /tmp/qemu-tap-locks/tap0.lock...
Traceback (most recent call last):
  File "/buildarea/lyang1/poky/scripts/runqemu", line 972, in <module>
    ret = main()
  File "/buildarea/lyang1/poky/scripts/runqemu", line 963, in main
    config.setup_network()
  File "/buildarea/lyang1/poky/scripts/runqemu", line 810, in setup_network
    self.setup_tap()
  File "/buildarea/lyang1/poky/scripts/runqemu", line 761, in setup_tap
    if self.acquire_lock():
  File "/buildarea/lyang1/poky/scripts/runqemu", line 182, in acquire_lock
    lock_descriptor = open(self.lock, 'w')
PermissionError: [Errno 13] Permission denied: '/tmp/qemu-tap-locks/tap0.lock'

Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 scripts/runqemu | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/scripts/runqemu b/scripts/runqemu
index b6bc0ba..3805685 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -168,14 +168,14 @@ class BaseConfig(object):
 
     def acquire_lock(self):
         logger.info("Acquiring lockfile %s..." % self.lock)
-        lock_descriptor = open(self.lock, 'w')
         try:
-            fcntl.flock(lock_descriptor, fcntl.LOCK_EX|fcntl.LOCK_NB)
+            self.lock_descriptor = open(self.lock, 'w')
+            fcntl.flock(self.lock_descriptor, fcntl.LOCK_EX|fcntl.LOCK_NB)
         except Exception as e:
             logger.info("Acquiring lockfile %s failed: %s" % (self.lock, e))
-            lock_descriptor.close()
+            if self.lock_descriptor:
+                self.lock_descriptor.close()
             return False
-        self.lock_descriptor = lock_descriptor
         return True
 
     def release_lock(self):
-- 
2.9.0