Fix #7398 (calibre-server (from 0.7.26 and HEAD) fails when --daemonize is used)

src/calibre/library/server/main.py

@@ -5,7 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys
+import sys, os
 from threading import Thread
 
 from calibre.library.server import server_config as config
@@ -63,15 +63,47 @@ The OPDS interface is advertised via BonJour automatically.
                 ' work in all environments.'))
     return parser
 
+def daemonize(stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
+    try:
+        pid = os.fork()
+        if pid > 0:
+            # exit first parent
+            sys.exit(0)
+    except OSError, e:
+        print >>sys.stderr, "fork #1 failed: %d (%s)" % (e.errno, e.strerror)
+        sys.exit(1)
+
+    # decouple from parent environment
+    os.chdir("/")
+    os.setsid()
+    os.umask(0)
+
+    # do second fork
+    try:
+        pid = os.fork()
+        if pid > 0:
+            # exit from second parent
+            sys.exit(0)
+    except OSError, e:
+        print >>sys.stderr, "fork #2 failed: %d (%s)" % (e.errno, e.strerror)
+        sys.exit(1)
+
+    # Redirect standard file descriptors.
+    si = file(stdin, 'r')
+    so = file(stdout, 'a+')
+    se = file(stderr, 'a+', 0)
+    os.dup2(si.fileno(), sys.stdin.fileno())
+    os.dup2(so.fileno(), sys.stdout.fileno())
+    os.dup2(se.fileno(), sys.stderr.fileno())
+
+
 
 def main(args=sys.argv):
     from calibre.library.database2 import LibraryDatabase2
     parser = option_parser()
     opts, args = parser.parse_args(args)
     if opts.daemonize and not iswindows:
-        from cherrypy.process.plugins import Daemonizer
-        d = Daemonizer(cherrypy.engine)
-        d.subscribe()
+        daemonize()
     if opts.pidfile is not None:
         from cherrypy.process.plugins import PIDFile
         PIDFile(cherrypy.engine, opts.pidfile).subscribe()