Simplify OS support checks

This branch of a2server only supports jessie and above, either Raspbian
or Debian.  While I was at it, I simplified the tests for what is and is
not a supported OS.  If there are bad kernels or firmwares we need to
work around those should be fixes.  This also means giving the user an
option to interrupt the installation if they are trying to install on a
Debian(ish) system that is too old or (more likely) too new.

At least ivan.sh is now using a2cloud's system_ident script.

scripts/system_ident

@@ -0,0 +1,44 @@
+#! /bin/bash
+# vim: set tabstop=4 shiftwidth=4 noexpandtab filetype=sh:
+
+# system_ident - identify your system for raspple2 if needed
+#
+# To the extent possible under law, T. Joseph Carter and Ivan Drucker have
+# waived all copyright and related or neighboring rights to the a2server
+# scripts themselves.  Software used or installed by these scripts is subject
+# to other licenses.  This work is published from the United States.
+
+if [[ -z $ras2_os || -z $ras2_arch ]]; then
+	ras2_os="unknown"
+	if hash lsb_release 2>/dev/null; then
+		if [[ -f /usr/bin/raspi-config ]]; then
+			ras2_os="rpi-$(lsb_release -cs)"
+		else
+			case "$(lsb_release -is)" in
+				Debian)
+					ras2_os="debian-$(lsb_release -cs)"
+					;;
+				*)
+					printf "\nUnknown OS with lsb_release\n"
+					lsb_release -a
+					;;
+			esac
+		fi
+	else
+		uname_s="$(uname -s)"
+		case "$uname_s" in
+			Darwin)
+				ras2_os="$uname_s"
+				;;
+			*)
+				printf "\nUnknown OS with uname -s\n$uname_s\n"
+				;;
+		esac
+	fi
+	ras2_arch="$(uname -m)"
+	export ras2_os ras2_arch
+fi
+
+if [[ $1 != -q ]]; then
+	printf "ras2_os=\"%s\"\nras2_arch=\"%s\"\n" "$ras2_os" "$ras2_arch"
+fi

setup/ivan.sh

@@ -16,22 +16,14 @@ if [[ ! -f "$top_src/.a2server_source" ]]; then
 	exit 1
 fi
 
+# Make sure ras2_{os,arch} get set
+. "$top_src/scripts/system_ident" -q
+
 # This is now in install.sh, get it from there
 a2serverVersion=$(grep '^a2serverVersion' "$top_src/install.sh" | cut -d '"' -f 2)
 
 compare_version="$top_src/scripts/compare_version"
 
-isRpi=
-[[ -f /usr/bin/raspi-config ]] && isRpi=1
-
-isDebian=
-if [[ "$(lsb_release -ds)" = Debian* ]]; then
-	debianVersion="$(lsb_release -rs)"
-	if [[ "$debianVersion" -ge 7 || $debianVersion == [a-z]* ]]; then
-		isDebian=1
-	fi
-fi
-
 if [[ -f /usr/local/etc/A2SERVER-version ]]; then
 	read installedVersion </usr/local/etc/A2SERVER-version
     if [[ $installedVersion != *.*.* ]]; then
@@ -116,41 +108,27 @@ if [[ "$installedVersion" != "0" ]] && "$compare_version" $installedVersion lt 1
 fi
 
 unsupportedOS=1
-if [[ $isRpi ]]; then #supported Raspbian? (16-Feb-15, 20-Jun-14, 09-Jan-14, etc)
+if [[ $ras2_os == debian-* || $ras2_os == rpi-* ]]; then
-	fwhash=$(zcat /usr/share/doc/raspberrypi-bootloader/changelog.Debian.gz | grep -m 1 'as of' | awk '{print $NF}')
+	read debianVersion < /etc/debian_version
-	fwsupported="-8aca5762- -462f3e3f476f7b6- -c32bc633039cd9- -9d34d0475f9-
+	if [[ $debianVersion == *.* ]]; then
-			-d4f5315cfac4e- -6f4a90c8cb8817f- -5dd9b4962e- -17c8799375-
+		if (( ${debianVersion%.*} >= 8 && ${debianVersion%.*} < 10 )); then
-			-960832a6c2590635216c296b6ee0bebf67b21d50-
+			unsupportedOS=
-			-2a329e0c7d8ea19c085bac5633aa4fccee0f21be-
+		fi
-			-b2420fc150ae4616f5d9ec24bdaedc630586a529-"
-	if [[ "$fwsupported" == *-$fwhash-* ]]; then
-		unsupportedOS=
 	fi
-elif [[ $isDebian ]]; then # supported Debian?
-	 debianVersion=$(cat /etc/debian_version)
-	 debianSupported="-9.2- -8.2- -7.9- -7.8- -7.6- -7.3-"
-	 [[ $debianSupported == *-$debianVersion-* ]] && unsupportedOS=
-fi
-
-if [[ $unsupportedOS && $isRpi ]]; then
-	echo
-	echo "A2SERVER and its installer scripts have been tested on Raspbian Wheezy,"
-	echo "Jessie, and Stretch though not this specific firmware version"
-	echo "(${fwhash:0:7}). Just FYI."
-	unsupportedOS=
-elif [[ $unsupportedOS && $isDebian ]]; then
-	echo
-	echo "A2SERVER and its installer scripts have been tested on Debian 7/8/9,"
-	echo "though not this specific point release ($debianVersion). Just FYI."
-	unsupportedOS=
 fi
 
 if [[ $unsupportedOS ]]; then
-	echo
+	cat <<-EOF
-	echo "WARNING: A2SERVER and its installer scripts have only been tested on"
+
-	echo "Debian and Raspbian. Continuing is probably fine, but might not be."
+	WARNING: A2SERVER and its installer scripts have only been tested on
-	echo "Theoretical worst case would be your operating system no longer works"
+	Debian and Raspbian wheezy, jessie, and stretch. It may work with later
-	echo "properly or data is lost, so consider backing up first."
+	versions, but it might not.  The theoretical worst case would be an OS
+	image that no longer works correctly or lost data, so you might want to
+	press ctrl-c here.  Otherwise press Return.
+
+	Detected system: $ras2_os ($ras2_arch)
+	EOF
+	read
 fi
 
 doSetup=1