Added SSH connection check.

[backmeupscotty.git] / backmeupscotty

diff --git a/backmeupscotty b/backmeupscotty
index ed41ae2b5a584e03906f3f25d73f92f61d056260..9087a17c2a2064fb8a7a031ee783caaed7ed3c52 100644 (file)
--- a/backmeupscotty
+++ b/backmeupscotty
@@ -18,22 +18,6 @@ function scottyerror {
     echo $(upperme): $@ >&2 
 }
 
-if [ $(pidof -x $(basename $0) | wc -w) -gt 2 ]; then 
-    scottyerror Another instance of $(basename $0) is already running!
-    exit 1
-fi
-
-while getopts "qn:" opt; do
-    case $opt in
-       q)
-           exec > /dev/null
-           ;;
-       n)
-           BACKUP_RUNEVERYNTHDAY=$OPTARG
-           ;;
-    esac
-done
-
 function grepbackups {
     ssh $REMOTE_HOST "ls $REMOTE_DIR" | grep -E '[0-9]+-[0-9]+'
 }
@@ -46,9 +30,8 @@ function isIncomplete {
     fi
 }
 
-function isIncompleteOrNthDay {
-    if isIncomplete || \
-       [ $(( ( $(date +%s) / (60*60*24) ) % $BACKUP_RUNEVERYNTHDAY )) -eq 0 ]; 
+function isNthDay {
+    if [ $(( ( $(date +%s) / (60*60*24) ) % $BACKUP_RUNEVERYNTHDAY )) -eq 0 ]; 
     then
        return 0
     else
@@ -56,6 +39,20 @@ function isIncompleteOrNthDay {
     fi 
 }
 
+function latestTooOld {
+    for oldbackup in $(grepbackups); do
+       tstamp=$(echo $oldbackup | cut -d'-' -f1)
+       
+       if [ $(( $(date +%s) - $tstamp )) -lt \
+           $(( $BACKUP_RUNEVERYNTHDAY*24*60*60 )) ]
+       then
+           return 1
+       fi
+    done
+
+    return 0
+}
+
 function scottysync {
     timestamp=$(date +%s)
 
@@ -116,51 +113,100 @@ function scottysync {
     done
 }
 
-function prepare {
-    scottyinfo "Preparing for sync"
+function deleteLock {
+    if ! rmdir /tmp/$(basename $0).lock; then
+       scottyerror "Could not delete lockfile /tmp/$(basename $0).lock!"
+    fi
 }
 
-function cleanup_abrt {
-    scottyinfo "No cleanup_abrt function was defined."
+function prepare {
+    scottyinfo "Preparing for sync"
 }
 
-function _cleanup_abrt {
+function cleanup_abort {
     scottyerror "Caught exit signal! Cleaning up..."
-    cleanup_abrt
+
+    cleanup ABORT
+
     if [ $(jobs -p) ]; then
        scottyerror TERMinating remaining child processes...
        kill $(jobs -p)
     fi
+
+    deleteLock
+
     exit
 }
 
-function prepare {
-    scottyinfo "No prepare function was defined."
+function cleanup {
+    scottyinfo "No cleanup function was defined."
 }
 
-function _prepare {
-    prepare
+function prepare {
+    scottyinfo "No prepare function was defined."
 }
 
 function cleanup_normal {
-    scottyinfo "No cleanup_normal function was defined."
+    cleanup
+    deleteLock
 }
 
-function _cleanup_normal {
-    cleanup_normal
+function printhelp {
+    cat <<EOF
+Usage: $(basename $0) [OPTION]...
+
+Recognized options:
+  -q   Only output errors
+  -n   Run only on nth day
+  -h   Print out this help
+EOF
 }
 
 function backmeupscotty {
-    if ! isIncompleteOrNthDay; then
-       scottyinfo "This is not the nth day and no incomplete backup exists."
+    while getopts "qn:h" opt; do
+       case $opt in
+           q)
+               exec > /dev/null
+               ;;
+           n)
+               BACKUP_RUNEVERYNTHDAY=$OPTARG
+               ;;
+           h)
+               printhelp
+                exit 0
+                ;;
+       esac
+    done
+
+    if (! ssh -q $REMOTE_HOST exit); then
+       scottyerror "Could not establish SSH connection to $REMOTE_HOST!"
+       exit 1
+    fi
+
+    if isNthDay; then
+       scottyinfo "This is the nth day."
+    elif latestTooOld; then
+       scottyinfo "The latest backup is too old."
+    else
+       scottyinfo "No backup has to be done. Exiting."
        exit 0
     fi
 
-    trap _cleanup_abrt EXIT
+    scottyinfo "Performing backup."
 
-    _prepare
+    trap cleanup_abort EXIT
+
+    prepare
     scottysync
-    _cleanup_normal
 
-    trap - EXIT
+    trap cleanup_normal EXIT
+
+    exit 0
 }
+
+if ! mkdir /tmp/$(basename $0).lock; then
+    scottyerror "Another instance of $(basename $0) is still running!"
+    exit 1
+else
+    trap deleteLock EXIT
+fi