[OE-core] [PATCHv3 1/3] runqemu: Allow to store more than one lock for network interfaces

[Anibal Limon]

I squashed the fix in the wrong patch that's because the v3 that are no
functional changes between v2 and v3.

Fixed acquired_lock method to only add the lock when acquire succeed.

Regards,
Anibal

On Mon, 1 Jul 2019 at 16:23, Aníbal Limón <anibal.limon at linaro.org> wrote:

> In order to support multiple tap devices in the same qemu virtual
> machine.
>
> Signed-off-by: Aníbal Limón <anibal.limon at linaro.org>
> ---
>  scripts/runqemu | 50 +++++++++++++++++++++++++------------------------
>  1 file changed, 26 insertions(+), 24 deletions(-)
>
> diff --git a/scripts/runqemu b/scripts/runqemu
> index 4079f2b17d..38dd1c30d9 100755
> --- a/scripts/runqemu
> +++ b/scripts/runqemu
> @@ -181,8 +181,7 @@ class BaseConfig(object):
>          self.audio_enabled = False
>          self.tcpserial_portnum = ''
>          self.custombiosdir = ''
> -        self.lock = ''
> -        self.lock_descriptor = None
> +        self.lock_descriptors = {}
>          self.bitbake_e = ''
>          self.snapshot = False
>          self.wictypes = ('wic', 'wic.vmdk', 'wic.qcow2', 'wic.vdi')
> @@ -204,30 +203,32 @@ class BaseConfig(object):
>          # avoid cleanup twice
>          self.cleaned = False
>
> -    def acquire_lock(self, error=True):
> -        logger.debug("Acquiring lockfile %s..." % self.lock)
> +    def acquire_lock(self, lock, error=True):
> +        logger.debug("Acquiring lockfile %s..." % lock)
> +        descriptor = None
>          try:
> -            self.lock_descriptor = open(self.lock, 'w')
> -            fcntl.flock(self.lock_descriptor, fcntl.LOCK_EX|fcntl.LOCK_NB)
> +            descriptor = open(lock, 'w')
> +            fcntl.flock(descriptor, fcntl.LOCK_EX|fcntl.LOCK_NB)
>          except Exception as e:
> -            msg = "Acquiring lockfile %s failed: %s" % (self.lock, e)
> +            msg = "Acquiring lockfile %s failed: %s" % (lock, e)
>              if error:
>                  logger.error(msg)
>              else:
>                  logger.info(msg)
> -            if self.lock_descriptor:
> -                self.lock_descriptor.close()
> -                self.lock_descriptor = None
> +            if descriptor:
> +                descriptor.close()
> +                descriptor = None
>              return False
> +        self.lock_descriptors[lock] = descriptor
>          return True
>
> -    def release_lock(self):
> -        if self.lock_descriptor:
> -            logger.debug("Releasing lockfile for tap device '%s'" %
> self.tap)
> -            fcntl.flock(self.lock_descriptor, fcntl.LOCK_UN)
> -            self.lock_descriptor.close()
> -            os.remove(self.lock)
> -            self.lock_descriptor = None
> +    def release_lock(self, lock):
> +        if self.lock_descriptors[lock]:
> +            logger.debug("Releasing lockfile for tap device '%s'" % lock)
> +            fcntl.flock(self.lock_descriptors[lock], fcntl.LOCK_UN)
> +            self.lock_descriptors[lock].close()
> +            os.remove(lock)
> +            self.lock_descriptors[lock] = None
>
>      def get(self, key):
>          if key in self.d:
> @@ -1016,8 +1017,8 @@ class BaseConfig(object):
>              if os.path.exists('%s.skip' % lockfile):
>                  logger.info('Found %s.skip, skipping %s' % (lockfile, p))
>                  continue
> -            self.lock = lockfile + '.lock'
> -            if self.acquire_lock(error=False):
> +            lock = lockfile + '.lock'
> +            if self.acquire_lock(lock, error=False):
>                  tap = p
>                  logger.info("Using preconfigured tap device %s" % tap)
>                  logger.info("If this is not intended, touch %s.skip to
> make runqemu skip %s." %(lockfile, tap))
> @@ -1035,8 +1036,8 @@ class BaseConfig(object):
>              cmd = ('sudo', self.qemuifup, str(uid), str(gid),
> self.bindir_native)
>              tap = subprocess.check_output(cmd).decode('utf-8').strip()
>              lockfile = os.path.join(lockdir, tap)
> -            self.lock = lockfile + '.lock'
> -            self.acquire_lock()
> +            lock = lockfile + '.lock'
> +            self.acquire_lock(lock)
>              self.cleantap = True
>              logger.debug('Created tap: %s' % tap)
>
> @@ -1268,8 +1269,8 @@ class BaseConfig(object):
>          cmds = shlex.split(cmd)
>          logger.info('Running %s\n' % cmd)
>          pass_fds = []
> -        if self.lock_descriptor:
> -            pass_fds = [self.lock_descriptor.fileno()]
> +        if self.lock_descriptors.keys():
> +            pass_fds = [self.lock_descriptors[lock].fileno() for lock in
> self.lock_descriptors.keys()]
>          process = subprocess.Popen(cmds, stderr=subprocess.PIPE,
> pass_fds=pass_fds)
>          self.qemupid = process.pid
>          retcode = process.wait()
> @@ -1291,7 +1292,8 @@ class BaseConfig(object):
>              cmd = ('sudo', self.qemuifdown, self.tap, self.bindir_native)
>              logger.debug('Running %s' % str(cmd))
>              subprocess.check_call(cmd)
> -        self.release_lock()
> +        for lock in self.lock_descriptors.keys():
> +            self.release_lock(lock)
>
>          if self.nfs_running:
>              logger.info("Shutting down the userspace NFS server...")
> --
> 2.20.1
>
>
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