systemd: add socket activation example

.gitignore

@@ -3,7 +3,7 @@ CMakeCache.txt
 CMakeFiles
 build
 cmake_install.cmake
-lws-minimal*
+build/lws-minimal*
 Makefile
 .cproject
 .project

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/CMakeLists.txt

@@ -0,0 +1,44 @@
+project(lws-minimal-http-server-systemd-socketact C)
+cmake_minimum_required(VERSION 3.5)
+find_package(libwebsockets CONFIG REQUIRED)
+list(APPEND CMAKE_MODULE_PATH ${LWS_CMAKE_DIR})
+include(CheckCSourceCompiles)
+include(LwsCheckRequirements)
+
+set(SRCS minimal-http-server-systemd-socketact.c)
+
+add_compile_options(-Wall -Wextra -Werror -pedantic -g -Ofast
+                    -DINSTALL_SHARE=\"${CMAKE_INSTALL_PREFIX}/share/${PROJECT_NAME}\")
+
+set(requirements 1)
+require_lws_config(LWS_ROLE_H1 1 requirements)
+require_lws_config(LWS_WITH_SERVER 1 requirements)
+require_lws_config(LWS_HAVE_SYSTEMD_H 1 requirements)
+
+if (requirements)
+	add_executable(${PROJECT_NAME} ${SRCS})
+
+	if (websockets_shared)
+		target_link_libraries(${PROJECT_NAME}	websockets_shared
+							${LIBWEBSOCKETS_DEP_LIBS})
+		add_dependencies(${PROJECT_NAME}	websockets_shared)
+	else()
+		target_link_libraries(${PROJECT_NAME}	websockets
+							${LIBWEBSOCKETS_DEP_LIBS})
+	endif()
+
+	install(TARGETS ${PROJECT_NAME}
+		DESTINATION bin)
+
+	install(FILES   mount-origin/404.html
+			mount-origin/favicon.ico
+			mount-origin/index.html
+			mount-origin/libwebsockets.org-logo.svg
+			mount-origin/strict-csp.svg
+		DESTINATION share/${PROJECT_NAME})
+
+	install(FILES	lws-minimal-http-server-systemd-socketact.service
+			lws-minimal-http-server-systemd-socketact.socket
+		DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/systemd/system)
+
+endif()

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/README.md

@@ -0,0 +1,23 @@
+# lws minimal http server systemd socketact
+
+## build
+
+```
+ $ cmake . && make && sudo make install
+```
+
+This will by default install to `/usr/local` and the systemd pieces to `/usr/local/lib/systemd/system`
+
+Assets will go to `/usr/local/share/lws-minimal-http-server-systemd-socketact/` and
+the test app will know to fetch things from there.
+
+## configure
+
+```
+ $ systemctl --user link /usr/local/lib/systemd/system/lws-minimal-http-server-systemd-socketact.service /usr/local/lib/systemd/system/lws-minimal-http-server-systemd-socketact.socket
+ $ systemctl --user start lws-minimal-http-server-systemd-socketact.socket
+```
+
+Then the test server should be autoexecuted by systemd if you try to browse to `http://127.0.0.1:7681`
+
+

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/lws-minimal-http-server-systemd-socketact.service

@@ -0,0 +1,5 @@
+[Unit]
+Description=LWS minimal example for socket activation
+
+[Service]
+ExecStart=/usr/local/bin/lws-minimal-http-server-systemd-socketact

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/lws-minimal-http-server-systemd-socketact.socket

@@ -0,0 +1,6 @@
+[Socket]
+ListenStream=7681
+
+[Install]
+WantedBy=sockets.target
+

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/minimal-http-server-systemd-socketact.c

@@ -0,0 +1,74 @@
+/*
+ * lws-minimal-http-server-systemd-socketact
+ *
+ * Written in 2010-2024 by Andy Green <[email protected]>
+ *
+ * This file is made available under the Creative Commons CC0 1.0
+ * Universal Public Domain Dedication.
+ *
+ * This demonstrates the most minimal http server you can make with lws.
+ *
+ * To keep it simple, it serves stuff from the subdirectory
+ * "./mount-origin" of the directory it was started in.
+ * You can change that by changing mount.origin below.
+ */
+
+#include <libwebsockets.h>
+#include <string.h>
+#include <signal.h>
+
+static int interrupted;
+
+static const struct lws_http_mount mount = {
+	.mountpoint			= "/",		    /* mountpoint URL */
+	.origin				= INSTALL_SHARE,    /* serve from dir */
+	.def				= "index.html",	  /* default filename */
+	.origin_protocol		= LWSMPRO_FILE,	    /* files in a dir */
+	.mountpoint_len			= 1,		        /* char count */
+};
+
+void sigint_handler(int sig)
+{
+	interrupted = 1;
+}
+
+int main(int argc, const char **argv)
+{
+	struct lws_context_creation_info info;
+	struct lws_context *cx;
+	int n = 0;
+
+	lws_context_info_defaults(&info, NULL);
+	info.default_loglevel		= LLL_USER | LLL_ERR | LLL_WARN;
+	info.fd_limit_per_thread        = 128;
+	if (lws_systemd_inherited_fd(0, &info)) {
+		lwsl_err("This example needs to run from systemd "
+			 "socket activation (see README.md)\n");
+		return 1;
+	}
+	lws_cmdline_option_handle_builtin(argc, argv, &info);
+
+	signal(SIGINT, sigint_handler);
+
+	lwsl_user("LWS minimal http server via socket activation | "
+		  "visit http://localhost:%u\n", info.port);
+
+	info.mounts			= &mount;
+	info.error_document_404		= "/404.html";
+	info.options =
+		LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
+
+	cx = lws_create_context(&info);
+	if (!cx) {
+		lwsl_err("lws init failed\n");
+		return 1;
+	}
+
+	n = 0;
+	while (n >= 0 && !interrupted)
+		n = lws_service(cx, 0);
+
+	lws_context_destroy(cx);
+
+	return 0;
+}

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/mount-origin/404.html

@@ -0,0 +1,9 @@
+<meta charset="UTF-8"> 
+<html>
+	<body>
+		<img src="libwebsockets.org-logo.svg"><br>
+		<h1>404</h1>
+		Sorry, that file doesn't exist.
+	</body>
+</html>
+

minimal-examples-lowlevel/http-server/minimal-http-server-systemd-socketact/mount-origin/index.html

@@ -0,0 +1,15 @@
+<html>
+ <head>
+  <meta charset=utf-8 http-equiv="Content-Language" content="en"/>
+ </head>
+	<body>
+		<img src="libwebsockets.org-logo.svg">
+		<img src="strict-csp.svg"><br>
+
+		Hello from the <b>minimal http server example</b>.
+		<br>
+		You can confirm the 404 page handler by going to this
+		nonexistant <a href="notextant.html">page</a>.
+	</body>
+</html>
+