grml-screen: do not get confused by externally created pidfiles

[grml-scripts-core.git] / usr_bin / grml-screen

diff --git a/usr_bin/grml-screen b/usr_bin/grml-screen
index 79e71df..73bdea9 100755 (executable)
--- a/usr_bin/grml-screen
+++ b/usr_bin/grml-screen
@@ -14,6 +14,45 @@
   sudo chmod 660       $TTY
   sudo chown $USER.tty $TTY
 
+# FIXME: fix for screen race-conditions
+PID_FILE_="/var/run/grml-screen"
+PID_FILE_CREATED_="false"
+MY_PID_="$$"
+if [ ! -d "/var/run/screen/S-$USER" ]; then
+    # no /var/run/screen/S-$USER and possible no /var/run/screen either -> locking
+    for i in `seq 40`; do   # 40*0.25 = 10 seconds
+        if lockfile-create --retry 0 $PID_FILE_; then
+            echo $MY_PID_ >$PID_FILE_
+            PID_FILE_CREATED_="true"
+            break
+        fi
+        sleep 0.25
+    done
+fi
+if [ $PID_FILE_CREATED_ = "true" ]; then
+    if [ -f $PID_FILE_ ]; then
+        # FORK BEGIN
+        (
+        for i in `seq 40`; do   # 40*0.25 = 10 seconds
+            if [ ! -d "/var/run/screen/S-$USER" ]; then
+                sleep 0.25  # educated guess
+            else
+                break
+            fi
+        done
+        if [ `cat $PID_FILE_` = $MY_PID_ ]; then
+            rm $PID_FILE_
+            lockfile-remove $PID_FILE_
+        fi
+        )&
+        # FORK END
+    else
+        SLEEP_TIME_="$(( $$ % 5 * 5 + 5 ))"
+        echo "grml-screen: Error could not create lockfile! (sleeping for $SLEEP_TIME_)"
+        sleep $SLEEP_TIME_
+    fi
+fi
+
 # now run screen with config
   cd $HOME     # important for e.g. hardcopy-feature
   # do we have a utf8 enabled terminal?