Packaging: Add initial support for AppImage.

Add an "appimage" target that will create an AppImage package. Current
AppImage tools assume that you only have one executable, so add
a custom AppRun wrapper that will let you run our associated CLI
utilities via symlinks, e.g.

    ln -s ./Wireshark-3.2.1-x86.appimage capinfos
    ./capinfos --help

Packaging requires both linuxdeployqt and appimagetool, although we
might be able to reduce this to just linuxdeployqt:

    https://github.com/probonopd/linuxdeployqt
    https://github.com/AppImage/AppImageKit

I haven't done much testing beyond running Wireshark and
capinfos. There are undoubtedly issues that need to be fixed.

Bug: 14464
Change-Id: Ic004ba1962e6a8630ebb017349d9b2c0462fd5fe
Reviewed-on: https://code.wireshark.org/review/30953
Reviewed-by: Gerald Combs <gerald@wireshark.org>

CMakeLists.txt

@@ -2721,6 +2721,11 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
 	find_program(RPMBUILD_EXECUTABLE rpmbuild)
 	find_program(DPKG_BUILDPACKAGE_EXECUTABLE dpkg-buildpackage)
 	find_program(GIT_EXECUTABLE git)
+	# Should we add appimaged's monitored directories
+	# as HINTS?
+	# https://github.com/AppImage/appimaged
+	find_program(LINUXDEPLOYQT_EXECUTABLE linuxdeployqt)
+	find_program(APPIMAGETOOL_EXECUTABLE appimagetool)
 endif()
 
 function(_SET_GITVERSION_CMAKE_VARIABLE OUTPUT_VARIABLE)
@@ -2825,6 +2830,54 @@ if(DPKG_BUILDPACKAGE_EXECUTABLE)
 	)
 endif()
 
+if(LINUXDEPLOYQT_EXECUTABLE AND APPIMAGETOOL_EXECUTALBE)
+	# The documentation at https://github.com/probonopd/linuxdeployqt
+	# says that you need to set CMAKE_BUILD_TYPE=Release and
+	# CMAKE_INSTALL_PREFIX=/usr. I (gcc) also had to set
+	# CMAKE_INSTALL_LIBDIR=/usr/lib.
+	if (CMAKE_BUILD_TYPE STREQUAL "Release" AND CMAKE_INSTALL_PREFIX STREQUAL "/usr" AND CMAKE_INSTALL_LIBDIR STREQUAL "/usr/lib" )
+		add_custom_target(appimage-prerequisites)
+		add_dependencies(appimage-prerequisites ${PROGLIST})
+	else()
+		add_custom_target(appimage-prerequisites
+			COMMAND echo "CMAKE_BUILD_TYPE isn't Release or CMAKE_INSTALL_PREFIX isn't /usr or CMAKE_INSTALL_LIBDIR isn't /usr/lib."
+			COMMAND false
+		)
+	endif()
+	set (_ai_appdir "${CMAKE_BINARY_DIR}/packaging/appimage/appdir")
+	add_custom_target(appimage-appdir
+		COMMAND ${CMAKE_COMMAND} -E make_directory "${_ai_appdir}"
+		COMMAND env DESTDIR=${_ai_appdir}
+			${CMAKE_COMMAND} --build . --target install
+		DEPENDS appimage-prerequisites
+	)
+	set(_exe_args)
+	foreach(_prog ${PROGLIST})
+		# XXX Is this the correct path?
+		list(APPEND _exe_args "-executable=${_ai_appdir}/usr/bin/${_prog}")
+	endforeach()
+	# linuxdeployqt currently clobbers AppRun:
+	# https://github.com/probonopd/linuxdeployqt/issues/159
+	# When that's fixed we will no longer need appimagetool. Until
+	# then, we need to prep and package in two steps:
+	# https://github.com/probonopd/linuxdeployqt/wiki/Custom-wrapper-script-instead-of-AppRun
+	add_custom_target(appimage-prep
+		COMMAND ${LINUXDEPLOYQT_EXECUTABLE}
+			"${_ai_appdir}/usr/share/applications/wireshark.desktop"
+			${_exe_args}
+		COMMAND rm -f "${_ai_appdir}/AppRun"
+		COMMAND install
+			"${CMAKE_SOURCE_DIR}/packaging/appimage/AppRun"
+			"${_ai_appdir}/AppRun"
+		DEPENDS appimage-appdir
+	)
+	add_custom_target(appimage
+		COMMAND env VERSION=${PROJECT_VERSION} ${APPIMAGETOOL_EXECUTABLE} appdir
+		WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/packaging/appimage"
+		DEPENDS appimage-prep
+	)
+endif()
+
 set(CLEAN_C_FILES
 	${dumpcap_FILES}
 	${wireshark_FILES}
@@ -3134,6 +3187,7 @@ if(SHELLCHECK_EXECUTABLE)
 	add_custom_command(TARGET shellcheck POST_BUILD
 		COMMAND shellcheck --external-sources
 			image/stock_icons/svg-to-png.sh
+			packaging/appimage/AppRun
 			packaging/macosx/osx-app.sh.in
 			packaging/macosx/osx-dmg.sh.in
 			tools/compress-pngs.sh

docbook/release-notes.asciidoc

@@ -64,6 +64,7 @@ since version 2.6.0:
 * Dumpcap now supports the `-a packets:NUM` and `-b packets:NUM` options.
 * Wireshark now includes a “No Reassembly” configuration profile.
 * Wireshark now supports the Russian language.
+* The build system now supports AppImage packages.
 
 === Removed Features and Support
 

packaging/appimage/AppRun

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+# Custom AppRun entry point that allows symlinking multiple
+# executables, e.g. wireshark, tshark, dumpcap, editcap, etc.
+
+# Adapted from
+# https://github.com/probonopd/ippsample/blob/feature/appimage/appimage/AppRun
+
+SELF=$(readlink -f "$0")
+HERE=${SELF%/*}
+
+# See if we were called by runtime.c, which sets APPIMAGE, ARGV0,
+# and APPDIR.
+if [ -n "$APPIMAGE" ] && [ -n "$ARGV0" ] ; then
+    BINARY_NAME=${ARGV0##*/}
+else
+    BINARY_NAME=${0##*/}
+fi
+
+if [ -e "$HERE/usr/bin/$BINARY_NAME" ] ; then
+    exec "$HERE/usr/bin/$BINARY_NAME" "$@"
+else
+    exec "$HERE/usr/bin/wireshark" "$@"
+fi