sandbox/_sandboxbwrap.py: Use --die-with-parentjuerg/die-with-parent

This ensures subprocesses are cleaned up when the bwrap parent dies.

This is available since bubblewrap 0.1.8. We skip the option if the host
bwrap does not support it.

2 files changed, 26 insertions, 0 deletions

diff --git a/buildstream/_platform/linux.py b/buildstream/_platform/linux.py
index c180cc60a..9a2bcd356 100644
--- a/buildstream/_platform/linux.py
+++ b/buildstream/_platform/linux.py
@@ -36,6 +36,9 @@ class Linux(Platform):
 
         self._user_ns_available = False
         self.check_user_ns_available(context)
+
+        self.check_die_with_parent_available(context)
+
         self._artifact_cache = OSTreeCache(context, enable_push=self._user_ns_available)
 
     def check_user_ns_available(self, context):
@@ -69,6 +72,23 @@ class Linux(Platform):
                         detail="Some builds may not function due to lack of uid / gid 0, " +
                         "artifacts created will not be trusted for push purposes."))
 
+    def check_die_with_parent_available(self, context):
+
+        # bwrap supports --die-with-parent since 0.1.8.
+        # Let's check whether the host bwrap supports it.
+        bwrap = utils.get_host_tool('bwrap')
+
+        try:
+            subprocess.check_call([
+                bwrap,
+                '--ro-bind', '/', '/',
+                '--die-with-parent',
+                'true'
+            ], stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+            self._die_with_parent_available = True
+        except subprocess.CalledProcessError:
+            self._die_with_parent_available = False
+
     @property
     def artifactcache(self):
         return self._artifact_cache
@@ -76,4 +96,5 @@ class Linux(Platform):
     def create_sandbox(self, *args, **kwargs):
         # Inform the bubblewrap sandbox as to whether it can use user namespaces or not
         kwargs['user_ns_available'] = self._user_ns_available
+        kwargs['die_with_parent_available'] = self._die_with_parent_available
         return SandboxBwrap(*args, **kwargs)
diff --git a/buildstream/sandbox/_sandboxbwrap.py b/buildstream/sandbox/_sandboxbwrap.py
index cab178f0f..02f6ab30a 100644
--- a/buildstream/sandbox/_sandboxbwrap.py
+++ b/buildstream/sandbox/_sandboxbwrap.py
@@ -51,6 +51,7 @@ class SandboxBwrap(Sandbox):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.user_ns_available = kwargs['user_ns_available']
+        self.die_with_parent_available = kwargs['die_with_parent_available']
 
     def run(self, command, flags, *, cwd=None, env=None):
         stdout, stderr = self._get_output()
@@ -84,6 +85,10 @@ class SandboxBwrap(Sandbox):
         # are cleaned up when the bwrap process exits.
         bwrap_command += ['--unshare-pid']
 
+        # Ensure subprocesses are cleaned up when the bwrap parent dies.
+        if self.die_with_parent_available:
+            bwrap_command += ['--die-with-parent']
+
         # Add in the root filesystem stuff first.
         #
         # The rootfs is mounted as RW initially so that further mounts can be