SpawnProcess: use /dev/null fd from subclass

diff --git a/pym/_emerge/SpawnProcess.py b/pym/_emerge/SpawnProcess.py
index 065146c7518bed5ccf60e2868ee5f40176d30615..84493fe4206a6d614e7ae88814851f3ff8a93137 100644 (file)
--- a/pym/_emerge/SpawnProcess.py
+++ b/pym/_emerge/SpawnProcess.py
@@ -39,16 +39,6 @@ class SpawnProcess(SubProcess):
                if self.fd_pipes is None:
                        self.fd_pipes = {}
                fd_pipes = self.fd_pipes
-               fd_pipes.setdefault(0, sys.stdin.fileno())
-               fd_pipes.setdefault(1, sys.stdout.fileno())
-               fd_pipes.setdefault(2, sys.stderr.fileno())
-
-               # flush any pending output
-               for fd in fd_pipes.values():
-                       if fd == sys.stdout.fileno():
-                               sys.stdout.flush()
-                       if fd == sys.stderr.fileno():
-                               sys.stderr.flush()
 
                self._files = self._files_dict()
                files = self._files
@@ -62,22 +52,35 @@ class SpawnProcess(SubProcess):
                        logfile = self.logfile
 
                null_input = None
-               fd_pipes_orig = fd_pipes.copy()
-               if self.background:
+               if not self.background or 0 in fd_pipes:
+                       # Subclasses such as AbstractEbuildProcess may have already passed
+                       # in a null file descriptor in fd_pipes, so use that when given.
+                       pass
+               else:
                        # TODO: Use job control functions like tcsetpgrp() to control
                        # access to stdin. Until then, use /dev/null so that any
                        # attempts to read from stdin will immediately return EOF
                        # instead of blocking indefinitely.
                        null_input = open('/dev/null', 'rb')
                        fd_pipes[0] = null_input.fileno()
-               else:
-                       fd_pipes[0] = fd_pipes_orig[0]
+
+               fd_pipes.setdefault(0, sys.stdin.fileno())
+               fd_pipes.setdefault(1, sys.stdout.fileno())
+               fd_pipes.setdefault(2, sys.stderr.fileno())
+
+               # flush any pending output
+               for fd in fd_pipes.values():
+                       if fd == sys.stdout.fileno():
+                               sys.stdout.flush()
+                       if fd == sys.stderr.fileno():
+                               sys.stderr.flush()
 
                # WARNING: It is very important to use unbuffered mode here,
                # in order to avoid issue 5380 with python3.
                files.process = os.fdopen(master_fd, 'rb', 0)
                if logfile is not None:
 
+                       fd_pipes_orig = fd_pipes.copy()
                        fd_pipes[1] = slave_fd
                        fd_pipes[2] = slave_fd