Shell Programming and Scripting

usage () {
        cat >&2 <<EOF

Insert/delete IP addresses and name records
in hosts DNS.
OS: RHEL 5.5

Usage: ${0##*/} -i \$IP_ADDRESS -n \$NAME_RECORD [ -D optional ]

- Default is to Insert
- D switch to Delete

EOF

#!/bin/bash

#  Name: Eric
#  Version: 1.0
#  Date: 17/02/2014

CONFIG_FILE=/home/user1/hosts.unix-int
BACKUP_DIR=/home/user1/backup
LOG_PATH=/home/user1/log
LOG_FILE="user1_dns_${DATE}.log"
DATE=$(date +%Y%m%d)

# Default is to add record
REMOVE=N

# Usage
usage () {
        cat >&2 <<EOF

Insert/delete IP addresses and name records
in hosts DNS.
OS: RHEL 5.5

Usage: ${0##*/} -i \$IP_ADDRESS -n \$NAME_RECORD [ -D optional ]

- Default is to Insert
- D switch to Delete

EOF
}

# Manage error
error_log () {
        printf "[ $1 ]: %-30s\n" "$2" | tee -a $LOG_PATH/$LOG_FILE
}

# Validate if param are ok
validate_params () {
        results=$(echo $IP_ADDRESS | awk --re-interval -F"." '$0 ~ /^([0-9]{1,3}\.){3}[0-9]{1,3}$/ && $1 <=255 && $2 <= 255 && $3 <= 255 && $4 <= 255 {print}')
}

# Validate if inside cloud
validate_cloud () {
        awk '/####START/,/####FIN_CLOUD/{print}' $CONFIG_FILE | egrep -q '${IP_ADDRESS}|${NAME_RECORD}'
}

# Search for existing ip in configuration file
search_existant_ip () {
        grep -q "^${IP_ADDRESS}" $CONFIG_FILE
}

# Search for existing host in configuration file
search_existant_host () {
        grep -q "${NAME_RECORD}" $CONFIG_FILE
}

# Manage backups of host file
backup_host_file () {
        if [ ! -d $BACKUP_DIR ]; then
                mkdir $BACKUP_DIR
        fi
        cp -p $CONFIG_FILE "${CONFIG_FILE}.$DATE"
}

# Do the modification to the host file
add_host () {
        sed -i "/####FIN_CLOUD/i $IP_ADDRESS\t$NAME_RECORD" $CONFIG_FILE
        search_existant_ip
        if [[ $? -eq 1 ]]; then
                error_log "ERROR" "IP not found after ADDING $IP_ADDRESS"
                exit 1
        fi
        search_existant_host
        if [[ $? -eq 1 ]]; then
                error_log "ERROR" "HOST not found after ADDING $NAME_RECORD"
                exit 1
        fi
        error_log "ADD" "$IP_ADDRESS - $NAME_RECORD"
}

remove_host () {
        validate_cloud
        if [[ $? -eq 1 ]]; then
                error_log "ERROR" "IP/HOST Found but outside cloud"
                exit 1
        fi
        sed -i "/^$IP_ADDRESS\t$NAME_RECORD/d" $CONFIG_FILE
        search_existant_ip
        if [[ $? -eq 0 ]]; then
                error_log "ERROR" "IP found after REMOVING $IP_ADDRESS"
                exit 1
        fi
        search_existant_host
                if [[ $? -eq 0 ]]; then
                error_log "ERROR" "HOST found after REMOVING $NAME_RECORD"
                exit 1
        fi
        error_log "REMOVE" "$IP_ADDRESS - $NAME_RECORD"
}

# Main

# Check number of arguments
case $# in
        4|5) ;;
        *) usage; exit 1 ;;
esac

# Parse the arguments
while getopts i:n:R OPTION; do
  case "$OPTION" in
        D) REMOVE=Y
        ;;
        i) IP_ADDRESS=$OPTARG
        ;;
        n) NAME_RECORD=$OPTARG
        ;;
        :) usage ; exit 5
        ;;
        \?) usage ; exit 5
        ;;
  esac
done

shift $((OPTIND-1))

# Validate params

validate_params $IP_ADDRESS
if [[ -z $results ]]; then
        error_log "ERROR" "Incorrect IP parameters"
        exit 5
fi

search_existant_ip
if [[ $? -eq '0' ]] && [[ $REMOVE == 'N' ]]; then
        error_log "ERROR" "Ip Address already exists in host file"
        exit 1
fi

search_existant_host
if [[ $? -eq '0' ]] && [[ $REMOVE == 'N' ]]; then
        error_log "ERROR" "Name record already exists in host file"
        exit 1
fi

backup_host_file
if [[ $? -eq '1' ]]; then
        error_log "ERROR" "Problem with backup copy"
        exit 1
fi
if [[ $REMOVE == 'Y' ]]; then
        search_existant_ip
        if [[ $? -eq '1' ]]; then
                error_log "ERROR" "Ip Address not in host file"
                exit 1
        fi
        search_existant_host
        if [[ $? -eq '1' ]]; then
                error_log "ERROR" "Host not in host file"
                exit 1
        fi
        remove_host
else
        add_host
fi

# Launch restart_named.sh

#service restart restart_named.sh
#/root/Restart_named.sh

exit 0

if [ -z "$KEYNAME" ]
then
        echo "Input key name" >&2
        read KEYNAME
fi

# Lots and lots of checking code for a valid value of KEYNAME