Add noexec /tmp detection — fall back to /usr/local/src for staging

Scripts auto-detect noexec /tmp by attempting to execute a test script.
If /tmp is noexec, staging directory falls back to /usr/local/src.
Supports mixed fleets with both noexec and standard /tmp mounts.

Updated: deploy-exporter (1.1), install-node-exporter (1.2),
install-prometheus-stack (3.2), update-prometheus-stack (1.02),
install-snort (1.02), install-ntfy-server (1.1), install-bot-monitor (1.2)

update-prometheus-stack.sh

@@ -35,14 +35,26 @@ set -euo pipefail
 ##                                                                      ##
 ##  Author: Phil Connor                                                 ##
 ##  Contact: pconnor@ara.com                                            ##
-##  Version: 1.01                                                       ##
+##  Version: 1.02                                                       ##
 ##########################################################################
 
 BINDIR="/usr/local/bin"
 PROMDIR="/etc/prometheus"
 BACKUPDIR="${PROMDIR}/backups"
 LOGFILE="/var/log/prometheus-update.log"
-TMPDIR_BASE="/tmp/prometheus-update-$$"
+# Detect noexec /tmp — fall back to /usr/local/src
+STAGE_DIR="/tmp"
+_exec_test=$(mktemp /tmp/.exec_test.XXXXXX 2>/dev/null)
+if [[ -n "$_exec_test" ]]; then
+    printf '#!/bin/sh\nexit 0\n' > "$_exec_test"
+    chmod +x "$_exec_test"
+    "$_exec_test" 2>/dev/null || STAGE_DIR="/usr/local/src"
+    rm -f "$_exec_test"
+else
+    STAGE_DIR="/usr/local/src"
+fi
+
+TMPDIR_BASE="${STAGE_DIR}/prometheus-update-$$"
 CHECK_ONLY=false
 BACKUP_ONLY=false
 FORCE=false