diff options
Diffstat (limited to '')
| -rwxr-xr-x | heartbeat/symlink | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/heartbeat/symlink b/heartbeat/symlink new file mode 100755 index 0000000..decd9f7 --- /dev/null +++ b/heartbeat/symlink @@ -0,0 +1,245 @@ +#!/bin/sh +# +# +# An OCF RA that manages a symlink +# +# Copyright (c) 2011 Dominik Klein +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of version 2 of the GNU General Public License as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it would be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. +# +# Further, this software is distributed without any warranty that it is +# free of the rightful claim of any third person regarding infringement +# or the like. Any license provided herein, whether implied or +# otherwise, applies only to this software file. Patent licenses, if +# any, provided herein do not apply to combinations of this program with +# other software, or any other product whatsoever. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write the Free Software Foundation, +# Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. +# + +####################################################################### +# Initialization: + +: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat} +. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs + +####################################################################### + +meta_data() { + cat <<END +<?xml version="1.0"?> +<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd"> +<resource-agent name="symlink" version="1.1"> +<version>1.0</version> + +<longdesc lang="en"> +This resource agent that manages a symbolic link (symlink). + +It is primarily intended to manage configuration files which should be +enabled or disabled based on where the resource is running, such as +cron job definitions and the like. +</longdesc> +<shortdesc lang="en">Manages a symbolic link</shortdesc> +<parameters> +<parameter name="link" required="1"> +<longdesc lang="en"> +Full path of the symbolic link to be managed. This must obviously be +in a filesystem that supports symbolic links. +</longdesc> +<shortdesc lang="en">Full path of the symlink</shortdesc> +<content type="string"/> +</parameter> +<parameter name="target" required="1"> +<longdesc lang="en"> +Full path to the link target (the file or directory which the symlink points to). +</longdesc> +<shortdesc lang="en">Full path to the link target</shortdesc> +<content type="string" /> +</parameter> +<parameter name="backup_suffix"> +<longdesc lang="en"> +A suffix to append to any files that the resource agent moves out of +the way because they clash with "link". + +If this is unset (the default), then the resource agent will simply +refuse to create a symlink if it clashes with an existing file. +</longdesc> +<shortdesc lang="en">Suffix to append to backup files</shortdesc> +<content type="string" /> +</parameter> +</parameters> +<actions> +<action name="start" timeout="15s" /> +<action name="stop" timeout="15s" /> +<action name="monitor" depth="0" timeout="15s" interval="60s"/> +<action name="meta-data" timeout="5s" /> +<action name="validate-all" timeout="10s" /> +</actions> +</resource-agent> +END +} + +symlink_monitor() { + # This applies the following logic: + # + # * If $OCF_RESKEY_link does not exist, then the resource is + # definitely stopped. + # + # * If $OCF_RESKEY_link exists and is a symlink that points to + # ${OCF_RESKEY_target}, then the resource is definitely started. + # + # * If $OCF_RESKEY_link exists, but is anything other than a + # symlink to ${OCF_RESKEY_target}, then the status depends on whether + # ${OCF_RESKEY_backup_suffix} is set: + # + # - if ${OCF_RESKEY_backup_suffix} is set, then the resource is + # simply not running. The existing file will be moved out of + # the way, to ${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}, + # when the resource starts. + # + # - if ${OCF_RESKEY_backup_suffix} is not set, then an existing + # file ${OCF_RESKEY_link} is an error condition, and the + # resource can't start here. + rc=$OCF_ERR_GENERIC + + # Using ls here instead of "test -e", as "test -e" returns false + # if the file does exist, but it a symlink to a file that doesn't + if ! ls "$OCF_RESKEY_link" >/dev/null 2>&1; then + ocf_log debug "$OCF_RESKEY_link does not exist" + rc=$OCF_NOT_RUNNING + elif [ ! -L "$OCF_RESKEY_link" ]; then + if [ -z "$OCF_RESKEY_backup_suffix" ]; then + ocf_exit_reason "$OCF_RESKEY_link exists but is not a symbolic link!" + exit $OCF_ERR_INSTALLED + else + ocf_log debug "$OCF_RESKEY_link exists but is not a symbolic link, will be moved to ${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix} on start" + rc=$OCF_NOT_RUNNING + fi + elif readlink -m "$OCF_RESKEY_link" | egrep -q "^$(readlink -m ${OCF_RESKEY_target})$"; then + ocf_log debug "$OCF_RESKEY_link exists and is a symbolic link to ${OCF_RESKEY_target}." + rc=$OCF_SUCCESS + else + if [ -z "$OCF_RESKEY_backup_suffix" ]; then + ocf_exit_reason "$OCF_RESKEY_link does not point to ${OCF_RESKEY_target}!" + exit $OCF_ERR_INSTALLED + else + ocf_log debug "$OCF_RESKEY_link does not point to ${OCF_RESKEY_target}, will be moved to ${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix} on start" + rc=$OCF_NOT_RUNNING + fi + fi + return $rc +} + +symlink_start() { + if ! symlink_monitor; then + if [ -e "$OCF_RESKEY_link" ]; then + if [ -z "$OCF_RESKEY_backup_suffix" ]; then + # Shouldn't happen, because symlink_monitor should + # have errored out. But there is a chance that + # something else put that file there after + # symlink_monitor ran. + ocf_exit_reason "$OCF_RESKEY_link exists and no backup_suffix is set, won't overwrite." + exit $OCF_ERR_GENERIC + else + ocf_log debug "Found $OCF_RESKEY_link, moving to ${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}" + ocf_run mv -v "$OCF_RESKEY_link" "${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}" \ + || exit $OCF_ERR_GENERIC + fi + fi + ocf_run ln -sv "$OCF_RESKEY_target" "$OCF_RESKEY_link" + symlink_monitor + return $? + else + return $OCF_SUCCESS + fi +} + +symlink_stop() { + if symlink_monitor; then + ocf_run rm -vf "$OCF_RESKEY_link" || exit $OCF_ERR_GENERIC + if ! symlink_monitor; then + if [ -e "${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}" ]; then + ocf_log debug "Found backup ${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}, moving to $OCF_RESKEY_link" + # if restoring the backup fails then still return with + # $OCF_SUCCESS, but log a warning + ocf_run -warn mv "${OCF_RESKEY_link}${OCF_RESKEY_backup_suffix}" "$OCF_RESKEY_link" + fi + return $OCF_SUCCESS + else + ocf_exit_reason "Removing $OCF_RESKEY_link failed." + return $OCF_ERR_GENERIC + fi + else + return $OCF_SUCCESS + fi +} + +symlink_validate_all() { + if [ "x${OCF_RESKEY_link}" = "x" ]; then + ocf_exit_reason "Mandatory parameter link is unset" + exit $OCF_ERR_CONFIGURED + fi + if [ "x${OCF_RESKEY_target}" = "x" ]; then + ocf_exit_reason "Mandatory parameter target is unset" + exit $OCF_ERR_CONFIGURED + fi + + # Having a non-existant target is technically not an error, as + # symlinks are allowed to point to non-existant paths. But it + # still doesn't hurt to warn people if the target does not exist + # (but only during non-probes). + if [ ! -e "${OCF_RESKEY_target}" ]; then + ocf_log warn "${OCF_RESKEY_target} does not exist!" + fi +} + +symlink_usage() { + cat <<EOF +usage: $0 {start|stop|monitor|validate-all|meta-data} +Expects to have a fully populated OCF RA-compliant environment set. +EOF +} + +if [ $# -ne 1 ]; then + symlink_usage + exit $OCF_ERR_ARGS +fi + +case $__OCF_ACTION in +meta-data) + meta_data + exit $OCF_SUCCESS + ;; +usage) + symlink_usage + exit $OCF_SUCCESS +esac + +# Everything except usage and meta-data must pass the validate test +symlink_validate_all || exit + +case $__OCF_ACTION in +start) + symlink_start + ;; +stop) + symlink_stop + ;; +status|monitor) + symlink_monitor + ;; +validate-all) + ;; +*) + symlink_usage + exit $OCF_ERR_UNIMPLEMENTED +esac +# exit code is the exit code (return code) of the last command (shell function) |