From 01f457d0bb1ba46bdeee552ae5fccc06612f01fa Mon Sep 17 00:00:00 2001
From: Al Williams <al.williams@awce.com>
Date: Mon, 1 Sep 2014 14:51:50 -0500
Subject: [PATCH 1/3] Adds a few useful scripts for auto upload and periodic
 download sync

---
 scripts/crontab.txt  |  5 +++++
 scripts/grive-incron | 34 ++++++++++++++++++++++++++++++++++
 scripts/incron.txt   |  3 +++
 scripts/readme.txt   | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+)
 create mode 100644 scripts/crontab.txt
 create mode 100755 scripts/grive-incron
 create mode 100644 scripts/incron.txt
 create mode 100644 scripts/readme.txt

diff --git a/scripts/crontab.txt b/scripts/crontab.txt
new file mode 100644
index 00000000..029d6597
--- /dev/null
+++ b/scripts/crontab.txt
@@ -0,0 +1,5 @@
+# This example runs grive on /home/USER/gdrive
+# See man crontab for format
+# This line runs at 5 after the hour and 35 after the hour
+
+5,35 * * * * /usr/bin/grive -p /home/USER/gdrive
diff --git a/scripts/grive-incron b/scripts/grive-incron
new file mode 100755
index 00000000..40ed76d6
--- /dev/null
+++ b/scripts/grive-incron
@@ -0,0 +1,34 @@
+#!/bin/bash
+
+# Allow grive to be called from incron
+# if your path is /home/User/gdrivef and this file is in /usr/local/bin then use the following incrontab line:
+# /home/User/gdrive IN_CREATE,IN_DELETE,IN_CLOSE_WRITE,IN_MOVE /usr/local/bin/grive-incron $# /home/User/gdrive
+
+# grive-incron a bash script to allow automatic push to gdrive from a directory
+# It is made to be called by # incron 
+#
+# Copyright (C) 2014 Al Williams (al.williams@awce.com)
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+# You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
+
+if [ $# != 2 ] 
+then
+  >&2 echo Call from incron: \$# directory
+  exit 1
+fi
+if [ "$1" == .grive -o "$1" == .grive_state ] 
+then
+  exit 0  # ignore grive housekeeping files
+fi
+# Don't run multiple copies at once
+N=2
+while [ "$N" != 1 ]
+do
+    N=$( pgrep -c -u "$USER" grive-? )  # assume if 1 it is me!
+    if [ "$N" != 1 ]
+      then sleep 1
+      fi
+done
+exec grive -p "$2"
diff --git a/scripts/incron.txt b/scripts/incron.txt
new file mode 100644
index 00000000..99806945
--- /dev/null
+++ b/scripts/incron.txt
@@ -0,0 +1,3 @@
+# Fix path below (2 places) and location of grive-incron script
+/home/USER/gdrive IN_CREATE,IN_DELETE,IN_CLOSE_WRITE,IN_MOVE /usr/bin/grive-incron $# /home/USER/gdrive
+
diff --git a/scripts/readme.txt b/scripts/readme.txt
new file mode 100644
index 00000000..ea661d6a
--- /dev/null
+++ b/scripts/readme.txt
@@ -0,0 +1,40 @@
+This directory contains a simple script that allows calling
+grive from incron. This will cause any changes you make
+to the local directory to automatically call grive to 
+update Google Drive. You can copy the script to a location on your 
+path:
+
+sudo cp grive-incron /usr/local/bin
+
+To make this work, you also need to insert the contents of incrontab.txt
+into your incrontab (after changing the paths to suit your 
+installation).
+
+To do this run:
+incrontab -e
+
+Then use the editor that appears to insert the line with your custom
+paths. You can ignore lines that start with # -- they are just comments
+although you can paste them into the incrontab if you like.
+
+To get the reverse, you can do a similar command in your crontab (see
+crontab.txt). The example syncs at 5 and 35 minutes after each hour
+but you can customize that by changing the crontab line.
+
+crontab -e
+
+will bring up an editor. Copy the line without the # in front from
+crontab.txt after fixing it for your specific path names. You can 
+skip the # lines or include them, as before.
+
+You probably don't want to do a crontab sync every minute because
+grive takes some time to run. The grive-incron script stalls if
+another copy of it or grive is running for the current user to 
+prevent overrun, but the crontab entry has on such protection. If you
+prefer, you could use the same script with a dummy file name in crontab.
+Then your crontab line would look something like this:
+
+5,35 * * * * /usr/local/bin/grive-incron DUMMY /home/USER/gdrive
+
+The word DUMMY is just a placeholder. It does not have to refer to a real
+file.

From 1f5c6d4172a25638f497473984989bb3facdc294 Mon Sep 17 00:00:00 2001
From: Al Williams <al.williams@awce.com>
Date: Mon, 1 Sep 2014 15:47:06 -0500
Subject: [PATCH 2/3] Fixes deadlock problem but still possible for more than
 one grive to start

---
 scripts/grive-incron | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/scripts/grive-incron b/scripts/grive-incron
index 40ed76d6..6c55cca3 100755
--- a/scripts/grive-incron
+++ b/scripts/grive-incron
@@ -24,11 +24,13 @@ then
 fi
 # Don't run multiple copies at once
 N=2
-while [ "$N" != 1 ]
+DLY=1
+while [ "$N" != 0 ]
 do
-    N=$( pgrep -c -u "$USER" grive-? )  # assume if 1 it is me!
-    if [ "$N" != 1 ]
-      then sleep 1
+    N=$( pgrep -c -u "$USER" ^grive$ )  # assume if 1 it is me!
+    if [ "$N" != 0 ]
+      then sleep $DLY
+	DLY=$((DLY+5))
       fi
 done
 exec grive -p "$2"

From 00e998694d7e2f6e14e716aab1944f8779422875 Mon Sep 17 00:00:00 2001
From: Al Williams <al.williams@awce.com>
Date: Mon, 1 Sep 2014 16:16:58 -0500
Subject: [PATCH 3/3] Better fix for interlock using PID file

---
 scripts/grive-incron | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/scripts/grive-incron b/scripts/grive-incron
index 6c55cca3..cdebc201 100755
--- a/scripts/grive-incron
+++ b/scripts/grive-incron
@@ -13,6 +13,8 @@
 # This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 # You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
 
+PIDFILE=/tmp/grive-incron.lock
+
 if [ $# != 2 ] 
 then
   >&2 echo Call from incron: \$# directory
@@ -23,14 +25,28 @@ then
   exit 0  # ignore grive housekeeping files
 fi
 # Don't run multiple copies at once
-N=2
+
 DLY=1
-while [ "$N" != 0 ]
-do
-    N=$( pgrep -c -u "$USER" ^grive$ )  # assume if 1 it is me!
-    if [ "$N" != 0 ]
-      then sleep $DLY
-	DLY=$((DLY+5))
-      fi
+
+while true
+  do
+  while [ -f "$PIDFILE"  ] && kill -0 `cat "$PIDFILE"` 2>/dev/null
+    do 
+      sleep $DLY
+      DLY=$((DLY+1))
+      DLY=$((DLY % 10 ))  # no more than 10 seconds
+    done
+    if ! kill -0 `cat "$PIDFILE" 2>/dev/null` 2>/dev/null
+    then
+      rm -f "$PIDFILE"
+    fi
+    if (set -o noclobber; echo $$>"$PIDFILE" ) >/dev/null
+    then 
+	trap 'rm -f "$PIDFILE"' INT TERM EXIT
+	break
+    fi
 done
-exec grive -p "$2"
+grive -p "$2"
+rm -f "$PIDFILE"
+trap - INT TERM EXIT
+exit 0