agl-basesystem

1 files changed, 93 insertions, 0 deletions

diff --git a/external/poky/bitbake/lib/bb/daemonize.py b/external/poky/bitbake/lib/bb/daemonize.py
new file mode 100644
index 00000000..c937675e
--- /dev/null
+++ b/external/poky/bitbake/lib/bb/daemonize.py
@@ -0,0 +1,93 @@
+"""
+Python Daemonizing helper
+
+Originally based on code Copyright (C) 2005 Chad J. Schroeder but now heavily modified
+to allow a function to be daemonized and return for bitbake use by Richard Purdie
+"""
+
+import os
+import sys
+import io
+import traceback
+
+def createDaemon(function, logfile):
+    """
+    Detach a process from the controlling terminal and run it in the
+    background as a daemon, returning control to the caller.
+    """
+
+    # Ensure stdout/stderror are flushed before forking to avoid duplicate output
+    sys.stdout.flush()
+    sys.stderr.flush()
+
+    try:
+        # Fork a child process so the parent can exit.  This returns control to
+        # the command-line or shell.  It also guarantees that the child will not
+        # be a process group leader, since the child receives a new process ID
+        # and inherits the parent's process group ID.  This step is required
+        # to insure that the next call to os.setsid is successful.
+        pid = os.fork()
+    except OSError as e:
+        raise Exception("%s [%d]" % (e.strerror, e.errno))
+
+    if (pid == 0):      # The first child.
+        # To become the session leader of this new session and the process group
+        # leader of the new process group, we call os.setsid().  The process is
+        # also guaranteed not to have a controlling terminal.
+        os.setsid()
+        try:
+            # Fork a second child and exit immediately to prevent zombies.  This
+            # causes the second child process to be orphaned, making the init
+            # process responsible for its cleanup.  And, since the first child is
+            # a session leader without a controlling terminal, it's possible for
+            # it to acquire one by opening a terminal in the future (System V-
+            # based systems).  This second fork guarantees that the child is no
+            # longer a session leader, preventing the daemon from ever acquiring
+            # a controlling terminal.
+            pid = os.fork()     # Fork a second child.
+        except OSError as e:
+            raise Exception("%s [%d]" % (e.strerror, e.errno))
+
+        if (pid != 0):
+            # Parent (the first child) of the second child.
+            # exit() or _exit()?
+            # _exit is like exit(), but it doesn't call any functions registered
+            # with atexit (and on_exit) or any registered signal handlers.  It also
+            # closes any open file descriptors, but doesn't flush any buffered output.
+            # Using exit() may cause all any temporary files to be unexpectedly
+            # removed.  It's therefore recommended that child branches of a fork()
+            # and the parent branch(es) of a daemon use _exit().
+            os._exit(0)
+    else:
+        os.waitpid(pid, 0)
+        return
+
+    # The second child.
+
+    # Replace standard fds with our own
+    with open('/dev/null', 'r') as si:
+        os.dup2(si.fileno(), sys.stdin.fileno())
+
+    try:
+        so = open(logfile, 'a+')
+        os.dup2(so.fileno(), sys.stdout.fileno())
+        os.dup2(so.fileno(), sys.stderr.fileno())
+    except io.UnsupportedOperation:
+        sys.stdout = open(logfile, 'a+')
+
+    # Have stdout and stderr be the same so log output matches chronologically
+    # and there aren't two seperate buffers
+    sys.stderr = sys.stdout
+
+    try:
+        function()
+    except Exception as e:
+        traceback.print_exc()
+    finally:
+        bb.event.print_ui_queue()
+        # os._exit() doesn't flush open files like os.exit() does. Manually flush
+        # stdout and stderr so that any logging output will be seen, particularly
+        # exception tracebacks.
+        sys.stdout.flush()
+        sys.stderr.flush()
+        os._exit(0)