server: kill stdin/stdout/stderr

This ensures that nothing run from the server can touch the console, in
particular event handlers and python tasks, both of which can use bb.msg or
the bitbake loggers to send output to the UI in a correct fashion instead.

Signed-off-by: Chris Larson <chris_larson@mentor.com>

2 files changed, 24 insertions, 1 deletions

diff --git a/lib/bb/server/process.py b/lib/bb/server/process.py
index f3ad5da60..12e099a95 100644
--- a/lib/bb/server/process.py
+++ b/lib/bb/server/process.py
@@ -22,6 +22,7 @@
 
 import logging
 import signal
+import sys
 import time
 import bb
 import bb.event
@@ -29,6 +30,7 @@ from multiprocessing import Process, Event
 from bb.cooker import BBCooker
 
 logger = logging.getLogger('BitBake')
+NULL = open('/dev/null', 'a')
 
 class ServerCommunicator():
     def __init__(self, connection):
@@ -86,6 +88,13 @@ class ProcessServer(Process):
         self._idlefunctions[function] = data
 
     def run(self):
+        """Run the server, killing off stdin/stdout/stderr"""
+        with bb.utils.redirected_fds([sys.stdin, sys.stdout, sys.stderr],
+                                     [NULL, NULL, NULL]):
+            return self.main()
+
+    def main(self):
+        """Server main loop"""
         # Ensure logging messages get sent to the UI as events
         logger.addHandler(bb.event.LogHandler())
 
@@ -105,7 +114,6 @@ class ProcessServer(Process):
         self.event_queue.cancel_join_thread()
         bb.event.unregister_UIHhandler(self.event_handle)
         self.command_channel.close()
-        return
 
     def idle_commands(self, delay):
         nextsleep = delay
diff --git a/lib/bb/utils.py b/lib/bb/utils.py
index 48b120ce5..ea5af49cd 100644
--- a/lib/bb/utils.py
+++ b/lib/bb/utils.py
@@ -774,3 +774,18 @@ def init_logger(logger, verbose, debug, debug_domains):
 
     if debug_domains:
         bb.msg.set_debug_domains(debug_domains)
+
+@contextmanager
+def redirected_fds(from_files, to_files):
+    assert len(from_files) == len(to_files), 'from_files / to_files length mismatch'
+
+    old_fds = []
+    for position, fobj in enumerate(from_files):
+        fd = fobj.fileno()
+        old_fds.append(os.dup(fd))
+        os.dup2(to_files[position].fileno(), fd)
+
+    yield
+
+    for position, fd in enumerate(old_fds):
+        os.dup2(fd, from_files[position].fileno())