From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 8 Apr 2017 23:01:09 +0000 (+0100)
Subject: hippotatd: support daemonisation
X-Git-Url: https://git.distorted.org.uk/~mdw/hippotat/commitdiff_plain/d84dbf4bde624a66318086c61c387e6448c707e4

hippotatd: support daemonisation

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/hippotatd b/hippotatd
index 525e4a1..f4bc551 100755
--- a/hippotatd
+++ b/hippotatd
@@ -32,6 +32,7 @@ import os
 import tempfile
 import atexit
 import shutil
+import subprocess
 
 import twisted.internet
 from twisted.web.server import NOT_DONE_YET
@@ -366,6 +367,50 @@ def daemonise():
     glp.addObserver(emit)
     log_debug(DBG.INIT, 'starting to log to syslog')
 
+  #log.crit('daemonic hippotatd crashed', dflag=False)
+  if opts.daemon:
+    daemonic_reactor = (twisted.internet.interfaces.IReactorDaemonize
+                        .providedBy(reactor))
+    if daemonic_reactor: reactor.beforeDaemonize()
+    rfd, wfd = os.pipe()
+    childpid = os.fork()
+    if childpid:
+      # we are the parent
+      os.close(wfd)
+      st = os.read(rfd, 1)
+      try:
+        st = st[0]
+      except IndexError:
+        st = 127
+        log.critical('daemonic hippotatd crashed', dflag=False)
+      os._exit(st)
+    os.close(rfd)
+    os.setsid()
+    grandchildpid = os.fork()
+    if grandchildpid:
+      # we are the intermediate child
+      os._exit(0)
+
+    logger = subprocess.Popen(['logger','-d',
+                               '-t','hippotat(stderr)',
+                               '--id=%d' % os.getpid(),
+                               '-p',opts.syslogfacility + '.err'],
+                              stdin=subprocess.PIPE,
+                              stdout=subprocess.DEVNULL,
+                              stderr=subprocess.DEVNULL,
+                              restore_signals=True)
+    
+    nullfd = os.open('/dev/null', os.O_RDWR)
+    os.dup2(nullfd, 0)
+    os.dup2(nullfd, 1)
+    os.dup2(logger.stdin.fileno(), 2)
+    os.close(nullfd)
+    if daemonic_reactor: reactor.afterDaemonize()
+    log_debug(DBG.INIT, 'daemonised')
+    os.write(wfd, b'\0')
+    os.close(wfd)
+
+  if opts.syslogfacility is not None:
     glp.removeObserver(hippotatlib.file_log_observer)
 
 optparser.add_option('--ownsource', default=2,
@@ -380,6 +425,10 @@ optparser.add_option('--no-ownsource',
                      action='store_const', dest='ownsource', const=0,
                      help='source download disabled (for testing only)')
 
+optparser.add_option('--daemon',
+                     action='store_true', dest='daemon', default=False,
+                     help='daemonize (and log to syslog)')
+
 optparser.add_option('--syslog-facility',
                      nargs=1, type='string',action='store',
                      metavar='FACILITY', dest='syslogfacility',
@@ -388,7 +437,7 @@ optparser.add_option('--syslog-facility',
 
 common_startup(process_cfg)
 catch_termination()
-ipif = start_ipif(c.ipif_command, (lambda p,s,d: route(p,"[ipif]",s,d)))
 start_http()
 daemonise()
+ipif = start_ipif(c.ipif_command, (lambda p,s,d: route(p,"[ipif]",s,d)))
 common_run()