From: Michael Gebetsroither <michael@mgeb.org>
Date: Sat, 6 Nov 2010 19:03:58 +0000 (+0100)
Subject: grml-screen: fix for screen race-conditions on boot [Closes: issue921]
X-Git-Tag: v1.4.0~7
X-Git-Url: http://git.grml.org/?p=grml-scripts.git;a=commitdiff_plain;h=f9835a0551733e1540cf826f2a520ee96c342718

grml-screen: fix for screen race-conditions on boot [Closes: issue921]
---

diff --git a/usr_bin/grml-screen b/usr_bin/grml-screen
index 79e71df..7deeb77 100755
--- a/usr_bin/grml-screen
+++ b/usr_bin/grml-screen
@@ -14,6 +14,41 @@
   sudo chmod 660       $TTY
   sudo chown $USER.tty $TTY
 
+# FIXME: fix for screen race-conditions
+PID_FILE_="/var/run/grml-screen"
+MY_PID_="$$"
+if [ ! -d "/var/run/screen/S-$USER" ]; then
+    # no /var/run/screen/S-$USER and possible no /var/run/screen either -> locking
+    for i in `seq 40`; do   # 40*0.25 = 10 seconds
+        if lockfile-create --retry 0 $PID_FILE_; then
+            echo $MY_PID_ >$PID_FILE_
+            break
+        fi
+        sleep 0.25
+    done
+fi
+if [ -f $PID_FILE_ ]; then
+    # FORK BEGIN
+    (
+    for i in `seq 40`; do   # 40*0.25 = 10 seconds
+        if [ ! -d "/var/run/screen/S-$USER" ]; then
+            sleep 0.25  # educated guess
+        else
+            break
+        fi
+    done
+    if [ `cat $PID_FILE_` = $MY_PID_ ]; then
+        rm $PID_FILE_
+        lockfile-remove $PID_FILE_
+    fi
+    )&
+    # FORK END
+else
+    SLEEP_TIME_="$(( $$ % 5 * 5 + 5 ))"
+    echo "grml-screen: Error could not create lockfile! (sleeping for $SLEEP_TIME_)"
+    sleep $SLEEP_TIME_
+fi
+
 # now run screen with config
   cd $HOME     # important for e.g. hardcopy-feature
   # do we have a utf8 enabled terminal?