From 5eda3b6e853c9f1773dd8def54589e8f1ad2299e Mon Sep 17 00:00:00 2001
From: Fredrik Eriksson <feffe@fulh.ax>
Date: Wed, 17 Apr 2019 08:50:26 +0200
Subject: [PATCH] fork and reboot instead of just reboot; hopefully will make
 sure a mail is sent from cron even if a reboot happens

---
 bin/sau | 125 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 84 insertions(+), 41 deletions(-)

diff --git a/bin/sau b/bin/sau
index 8990527..03c4523 100755
--- a/bin/sau
+++ b/bin/sau
@@ -11,47 +11,7 @@ import sau
 import sau.services
 import sau.platforms
 
-
-def main():
-    conf = sau.config
-    log = logging.getLogger(sau.LOGNAME)
-    platform = sau.platforms.get_platform()
-
-    reboot_required = False
-    reboot_recommended = False
-
-    if conf.getboolean('default', 'do_system_upgrade', fallback=True):
-        reboot_required = platform.system_upgrade()
-
-    if conf.getboolean('default', 'do_package_upgrade', fallback=True):
-        platform.pkg_upgrade()
-
-    if conf.getboolean('default', 'do_service_restart', fallback=True):
-        reboot_recommended = sau.services.restart_services()
-
-    if conf.getboolean('default', 'do_reboot', fallback=False):
-        if reboot_required:
-            log.warning('Rebooting because of a system upgrade')
-        elif reboot_recommended:
-            log.warning('Rebooting because service restarts did not close all deleted files')
-        if reboot_required or reboot_recommended:
-            # sleep a little to make sure the above log-messages has reached
-            # syslog before we reboot
-            time.sleep(1)
-            os.system('/sbin/reboot')
-
-def _conf_level_to_logging_level(conf_level):
-    if conf_level.lower() == 'debug':
-        return logging.DEBUG
-    if conf_level.lower() == 'info':
-        return logging.INFO
-    if conf_level.lower() == 'warning':
-        return logging.WARNING
-    if conf_level.lower() == 'error':
-        return logging.error
-    return logging.DEBUG
-    
-if __name__ == '__main__':
+def init():
     sau.config = configparser.SafeConfigParser()
     conf = sau.config
 
@@ -82,4 +42,87 @@ if __name__ == '__main__':
     handler.setFormatter(formatter)
     handler.setLevel(conf_level)
     log.addHandler(handler)
+
+
+def fork_and_reboot():
+    log = logging.getLogger(sau.LOGNAME)
+    try:
+        pid = os.fork()
+        if pid != 0:
+            sys.exit(0)
+    except OSError as err:
+        log.error("Fork #1 failed when going for reboot: {}".format(err))
+        sys.exit(1)
+
+    os.chdir('/')
+    os.setsid()
+    os.umask(0)
+
+    try:
+        pid = os.fork()
+        if pid != 0:
+            sys.exit(0)
+    except OSError as err:
+        log.error("Fork #2 failed when going for reboot: {}".format(err))
+        sys.exit(1)
+
+    sys.stdout.flush()
+    sys.stderr.flush()
+    stdin = open(os.devnull, 'r')
+    stdout = open(os.devnull, 'a+')
+    stderr = open(os.devnull, 'a+')
+
+    os.dup2(stdin.fileno(), sys.stdin.fileno())
+    os.dup2(stdout.fileno(), sys.stdout.fileno())
+    os.dup2(stderr.fileno(), sys.stderr.fileno())
+
+    log.warning("New fork!")
+
+    # sleep for a short while to give parent time to exit
+    time.sleep(30)
+    try:
+        #log.error('would reboot now')
+        os.execv('/sbin/reboot', ['/sbin/reboot'])
+    except OSError as err:
+        log.error('Could not reboot: {}'.format(err))
+    sys.exit(1)
+
+def main():
+    conf = sau.config
+    log = logging.getLogger(sau.LOGNAME)
+    platform = sau.platforms.get_platform()
+
+    reboot_required = False
+    reboot_recommended = False
+
+    if conf.getboolean('default', 'do_system_upgrade', fallback=True):
+        reboot_required = platform.system_upgrade()
+
+    if conf.getboolean('default', 'do_package_upgrade', fallback=True):
+        platform.pkg_upgrade()
+
+    if conf.getboolean('default', 'do_service_restart', fallback=True):
+        reboot_recommended = sau.services.restart_services()
+
+    if conf.getboolean('default', 'do_reboot', fallback=False):
+        if reboot_required:
+            log.warning('Rebooting because of a system upgrade')
+        elif reboot_recommended:
+            log.warning('Rebooting because service restarts did not close all deleted files')
+        if reboot_required or reboot_recommended:
+            fork_and_reboot()
+
+def _conf_level_to_logging_level(conf_level):
+    if conf_level.lower() == 'debug':
+        return logging.DEBUG
+    if conf_level.lower() == 'info':
+        return logging.INFO
+    if conf_level.lower() == 'warning':
+        return logging.WARNING
+    if conf_level.lower() == 'error':
+        return logging.error
+    return logging.DEBUG
+    
+if __name__ == '__main__':
+    init()
     sys.exit(main())