allows use of system libwebsockets instead of bundled one (#9984)

* allows usage of system libwebsockets
* fixes problems that were preventing ACLK to work with LWS `4.1.`
* add LWS info to buildinfo

Co-authored-by: Austin S. Hemmelgarn <austin@netdata.cloud>

Makefile.am

@@ -712,8 +712,8 @@ netdata_SOURCES = $(NETDATA_FILES)
 if ENABLE_ACLK
 netdata_LDADD = \
     externaldeps/mosquitto/libmosquitto.a \
-    externaldeps/libwebsockets/libwebsockets.a \
     $(OPTIONAL_LIBCAP_LIBS) \
+    $(OPTIONAL_LWS_LIBS) \
     $(NETDATA_COMMON_LIBS) \
     $(NULL)
 else

aclk/aclk_lws_https_client.c

@@ -12,6 +12,8 @@
 struct simple_hcc_data {
     char *data;
     size_t data_size;
+    size_t written;
+    char lws_work_buffer[1024 + LWS_PRE];
     char *payload;
     int response_code;
     int done;
@@ -28,6 +30,10 @@ static int simple_https_client_callback(struct lws *wsi, enum lws_callback_reaso
     switch (reason) {
     case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ:
         debug(D_ACLK, "LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ");
+        if (perconn_data->data_size - 1 - perconn_data->written < len)
+            return 1;
+        memcpy(&perconn_data->data[perconn_data->written], in, len);
+        perconn_data->written += len;
         return 0;
     case LWS_CALLBACK_RECEIVE_CLIENT_HTTP:
         debug(D_ACLK, "LWS_CALLBACK_RECEIVE_CLIENT_HTTP");
@@ -35,11 +41,11 @@ static int simple_https_client_callback(struct lws *wsi, enum lws_callback_reaso
             error("Missing Per Connect Data");
             return -1;
         }
-        ptr = perconn_data->data;
-        n = perconn_data->data_size - 1;
+        n = sizeof(perconn_data->lws_work_buffer) - LWS_PRE;
+        ptr = perconn_data->lws_work_buffer + LWS_PRE;
         if (lws_http_client_read(wsi, &ptr, &n) < 0)
             return -1;
-        ptr[n] = '\0';
+        perconn_data->data[perconn_data->written] = '\0';
         return 0;
     case LWS_CALLBACK_WSI_DESTROY:
         debug(D_ACLK, "LWS_CALLBACK_WSI_DESTROY");

configure.ac

@@ -172,6 +172,15 @@ AC_ARG_ENABLE(
     ,
     [enable_ebpf="detect"]
 )
+AC_ARG_WITH(
+    [bundled-lws],
+    [AS_HELP_STRING([--with-bundled-lws=DIR], [Use a specific Libwebsockets static library @<:@default use system library@:>@])],
+    [
+        with_bundled_lws="yes"
+        bundled_lws_dir="${withval}"
+    ],
+    [with_bundled_lws="no"]
+)
 
 # -----------------------------------------------------------------------------
 # Enforce building with C99, bail early if we can't.
@@ -651,15 +660,27 @@ if test "$enable_cloud" != "no"; then
     fi
     AC_MSG_RESULT([${HAVE_libmosquitto_a}])
 
-    AC_MSG_CHECKING([if libwebsockets static lib is present])
-    if test -f "externaldeps/libwebsockets/libwebsockets.a"; then
-        LWS_CFLAGS="-I externaldeps/libwebsockets/include"
-        HAVE_libwebsockets_a="yes"
+    if test "${with_bundled_lws}" = "yes"; then
+        AC_MSG_CHECKING([if libwebsockets static lib is present])
+        if test -f "${bundled_lws_dir}/libwebsockets.a"; then
+            LWS_CFLAGS="-I ${bundled_lws_dir}/include"
+            OPTIONAL_LWS_LIBS="${bundled_lws_dir}/libwebsockets.a"
+            AC_MSG_RESULT([yes])
+            AC_DEFINE([BUNDLED_LWS], [1], [using statically linked libwebsockets])
+        else
+            AC_DEFINE([ACLK_NO_LWS], [1], [libwebsockets.a was not found during build.])
+            # this should be error if installer ever changes default to system
+            # as currently this is default we prefer building netdata without ACLK
+            # instead of error fail
+            AC_MSG_RESULT([no])
+            AC_MSG_WARN([You required static libwebsockets to be used but we can't use it. Disabling ACLK])
+        fi
     else
-        HAVE_libwebsockets_a="no"
-        AC_DEFINE([ACLK_NO_LWS], [1], [libwebsockets.a was not found during build.])
+        AC_CHECK_LIB([websockets],
+            [lws_get_vhost_by_name],
+            [OPTIONAL_LWS_LIBS="-lwebsockets"],
+            [AC_DEFINE([ACLK_NO_LWS], [1], [usable system libwebsockets was not found during build.])])
     fi
-    AC_MSG_RESULT([${HAVE_libwebsockets_a}])
 
     if test "${build_target}" = "linux" -a "${enable_cloud}" != "no"; then
         if test "${have_libcap}" = "yes" -a "${with_libcap}" = "no"; then
@@ -678,7 +699,7 @@ if test "$enable_cloud" != "no"; then
         AC_MSG_ERROR([You have asked for ACLK to be built but no json-c available. ACLK requires json-c])
 
     AC_MSG_CHECKING([if netdata agent-cloud-link can be enabled])
-    if test "${HAVE_libmosquitto_a}" = "yes" -a "${HAVE_libwebsockets_a}" = "yes" -a -n "${SSL_LIBS}" -a "${enable_jsonc}" = "yes"; then
+    if test "${HAVE_libmosquitto_a}" = "yes" -a -n "${OPTIONAL_LWS_LIBS}" -a -n "${SSL_LIBS}" -a "${enable_jsonc}" = "yes"; then
         can_enable_aclk="yes"
     else
         can_enable_aclk="no"
@@ -1452,6 +1473,7 @@ AC_SUBST([OPTIONAL_PROMETHEUS_REMOTE_WRITE_CFLAGS])
 AC_SUBST([OPTIONAL_PROMETHEUS_REMOTE_WRITE_LIBS])
 AC_SUBST([OPTIONAL_MONGOC_CFLAGS])
 AC_SUBST([OPTIONAL_MONGOC_LIBS])
+AC_SUBST([OPTIONAL_LWS_LIBS])
 
 # -----------------------------------------------------------------------------
 # Check if cmocka is available - needed for unit testing

daemon/buildinfo.c

@@ -68,7 +68,14 @@
 #ifdef ACLK_NO_LWS
 #define FEAT_LWS "NO"
 #else
-#define FEAT_LWS "YES"
+#ifdef ENABLE_ACLK
+#include <libwebsockets.h>
+#endif
+#ifdef BUNDLED_LWS
+#define FEAT_LWS "YES static"
+#else
+#define FEAT_LWS "YES shared-lib"
+#endif
 #endif
 
 #ifdef NETDATA_WITH_ZLIB
@@ -193,7 +200,11 @@ void print_build_info(void) {
     printf("    libcap:                  %s\n", FEAT_LIBCAP);
     printf("    libcrypto:               %s\n", FEAT_CRYPTO);
     printf("    libm:                    %s\n", FEAT_LIBM);
+#if defined(ENABLE_ACLK)
+    printf("    LWS:                     %s v%d.%d.%d\n", FEAT_LWS, LWS_LIBRARY_VERSION_MAJOR, LWS_LIBRARY_VERSION_MINOR, LWS_LIBRARY_VERSION_PATCH);
+#else
     printf("    LWS:                     %s\n", FEAT_LWS);
+#endif
     printf("    mosquitto:               %s\n", FEAT_MOSQUITTO);
     printf("    tcalloc:                 %s\n", FEAT_TCMALLOC);
     printf("    zlib:                    %s\n", FEAT_ZLIB);

netdata-installer.sh

@@ -234,6 +234,7 @@ USAGE: ${PROGRAM} [options]
   --enable-lto               Enable Link-Time-Optimization. Default: enabled
   --disable-lto
   --disable-x86-sse          Disable SSE instructions. By default SSE optimizations are enabled.
+  --use-system-lws           Use a system copy of libwebsockets instead of bundling our own (default is to use the bundled copy).
   --zlib-is-really-here or
   --libs-are-really-here     If you get errors about missing zlib or libuuid but you know it is available, you might
                              have a broken pkg-config. Use this option to proceed without checking pkg-config.
@@ -275,6 +276,7 @@ while [ -n "${1}" ]; do
   case "${1}" in
     "--zlib-is-really-here") LIBS_ARE_HERE=1 ;;
     "--libs-are-really-here") LIBS_ARE_HERE=1 ;;
+    "--use-system-lws") USE_SYSTEM_LWS=1 ;;
     "--dont-scrub-cflags-even-though-it-may-break-things") DONT_SCRUB_CFLAGS_EVEN_THOUGH_IT_MAY_BREAK_THINGS=1 ;;
     "--dont-start-it") DONOTSTART=1 ;;
     "--dont-wait") DONOTWAIT=1 ;;
@@ -641,7 +643,7 @@ copy_libwebsockets() {
 }
 
 bundle_libwebsockets() {
-  if [ -n "${NETDATA_DISABLE_CLOUD}" ]; then
+  if [ -n "${NETDATA_DISABLE_CLOUD}" ] || [ -n "${USE_SYSTEM_LWS}" ]; then
     return 0
   fi
 
@@ -668,6 +670,7 @@ bundle_libwebsockets() {
       copy_libwebsockets "${tmp}/libwebsockets-${LIBWEBSOCKETS_PACKAGE_VERSION}" &&
       rm -rf "${tmp}"; then
       run_ok "libwebsockets built and prepared."
+      NETDATA_CONFIGURE_OPTIONS="${NETDATA_CONFIGURE_OPTIONS} --with-bundled-lws=externaldeps/libwebsockets"
     else
       run_failed "Failed to build libwebsockets."
       if [ -n "${NETDATA_REQUIRE_CLOUD}" ]; then