From 2591fa5313bbeaf88d0a7c57706d764d5bf2e188 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Thu, 21 May 2020 09:37:59 +0200
Subject: use tmpDir for inter-instance communication - now we can change the
 target (reboot/shutdown) or even abort cleanly

---
 shutdownasap.1.in    |  4 ++--
 shutdownasap.conf.in |  4 ++--
 shutdownasap.in      | 45 ++++++++++++++++++++++++++++++++++-----------
 3 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/shutdownasap.1.in b/shutdownasap.1.in
index 51c804c..65ee4af 100644
--- a/shutdownasap.1.in
+++ b/shutdownasap.1.in
@@ -15,8 +15,8 @@ For actually shutting down it calls \fBsudo shutdown\fP or \fBsudo reboot\fP for
 .SH CONFIGURATION
 The configfile \fB#ETCDIR#/shutdownasap.conf\fP is a bash script, which defines the following variables and routines:
 .TP
-.B "pidFile"
-file to store pid in
+.B "tmpDir"
+shared run-time directory for all instances
 .TP
 .B "waitForDir"
 directory which must be empty before shutting down
diff --git a/shutdownasap.conf.in b/shutdownasap.conf.in
index 780dafa..d04d3ea 100755
--- a/shutdownasap.conf.in
+++ b/shutdownasap.conf.in
@@ -3,8 +3,8 @@
 # configuration file for shutdownasap
 # it should be named #ETCDIR#/shutdownasap.conf
 
-# shutdownasap's pid
-pidFile="/tmp/shutdownasap.pid"
+# directory for inter-instance communication, etc.
+tmpDir="/tmp/tmp.shutdownasap"
 
 # directory must be empty before shutdown
 waitForDir="/home/shutdown/.warteauf"
diff --git a/shutdownasap.in b/shutdownasap.in
index a32f92d..d2d471f 100755
--- a/shutdownasap.in
+++ b/shutdownasap.in
@@ -6,28 +6,39 @@ set -e
 
 . #ETCDIR#/shutdownasap.conf
 
-[ -r "${pidFile}" ] && ps aux | grep -q "^\S\+\s\+$(cat "${pidFile}") " && exit
-
-echo $$ > "${pidFile}"
+mkdir -p "${tmpDir}"
 
 quiet=false
-reboot=false
+intentionSet=false
 while [ $# -gt 0 ]; do
   case "$1" in
+    '-a')
+      echo 'none' >"${tmpDir}/intention"
+      exit
+    ;;
     '-q')
       quiet=true
     ;;
     '-r')
-      reboot=true
+      echo 'reboot' >"${tmpDir}/intention"
+      intentionSet=true
     ;;
     *)
-      >&2 echo 'usage: shutdownasap [-q] [-r]'
+      >&2 echo 'usage: shutdownasap [-q] [-a|-r]'
       exit 1
     ;;
   esac
   shift
 done
 
+if ! ${intentionSet}; then
+  echo 'shutdown' >"${tmpDir}/intention"
+fi
+
+[ -r "${tmpDir}/pid" ] && kill -0 "$(cat "${tmpDir}/pid")" && exit
+
+echo $$ > "${tmpDir}/pid"
+
 beforeWatchHook
 
 i=1
@@ -130,8 +141,20 @@ else
   pre=''
 fi
 
-if ${reboot}; then
-  ${pre} /sbin/reboot
-else
-  ${pre} /sbin/poweroff
-fi
+case "$(head -n1 "${tmpDir}/intention")" in
+  'reboot')
+    ${pre} /sbin/reboot
+  ;;
+  'shutdown')
+    ${pre} /sbin/poweroff
+  ;;
+  'none')
+    echo 'shutdown was aborted'
+  ;;
+  *)
+    printf 'intention "%s" not implemented\n' "$(head -n1 "${tmpDir}/intention")"
+    exit 1
+  ;;
+esac
+
+rm -rf --one-file-system "${tmpDir}"
-- 
cgit v1.2.3-54-g00ecf