[Buildroot] [PATCH 1/2] package/libwebsockets: fix build with openssl and without threads

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello Fabrice,

On Fri,  3 Jan 2020 11:59:50 +0100
Fabrice Fontaine <fontaine.fabrice@gmail.com> wrote:

> Fixes:
>  - http://autobuild.buildroot.org/results/6186b4718db285edadf7203d00ed72f8d76a31e4
> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> ---
>  ...ix-build-with-openssl-and-without-th.patch | 90 +++++++++++++++++++
>  1 file changed, 90 insertions(+)
>  create mode 100644 package/libwebsockets/0003-CMakeLists.txt-fix-build-with-openssl-and-without-th.patch
> 
> diff --git a/package/libwebsockets/0003-CMakeLists.txt-fix-build-with-openssl-and-without-th.patch b/package/libwebsockets/0003-CMakeLists.txt-fix-build-with-openssl-and-without-th.patch
> new file mode 100644
> index 0000000000..701a1cd67a
> --- /dev/null
> +++ b/package/libwebsockets/0003-CMakeLists.txt-fix-build-with-openssl-and-without-th.patch
> @@ -0,0 +1,90 @@
> +From 8d8bd8a8a09d2d9e937aee8c3e2b69810aa710fd Mon Sep 17 00:00:00 2001
> +From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> +Date: Wed, 1 Jan 2020 00:40:54 +0100
> +Subject: [PATCH] CMakeLists.txt: fix build with openssl and without threads
> +
> +Since version 3.1.0 and commit aa4143aebdb59f4f21094781fb3b6ab4649643a6,
> +-pthread is unconditionally added to CMAKE_REQUIRED_FLAGS even if
> +pthread.h is not found, this will result in a build failure with openssl
> +if the toolchain doesn't support threads:
> +
> +[  5%] Building C object CMakeFiles/websockets_shared.dir/lib/core/lws_dll2.c.o
> +In file included from /home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/include/libwebsockets.h:570,
> +                 from /home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/lib/core/private.h:130,
> +                 from /home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/lib/core/lws_dll2.c:22:
> +/home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/include/libwebsockets/lws-genhash.h:79:18: error: field 'ctx' has incomplete type
> +         HMAC_CTX ctx;
> +                  ^~~
> +
> +This build failure is raised because openssl functions are not correcly
> +detected:
> +
> +Determining if the function SSL_CTX_set1_param exists failed with the following output:
> +Change Dir: /home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/CMakeFiles/CMakeTmp
> +
> +Run Build Command(s):/usr/bin/make cmTC_06946/fast && make[1]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/CMakeFiles/CMakeTmp'
> +/usr/bin/make -f CMakeFiles/cmTC_06946.dir/build.make CMakeFiles/cmTC_06946.dir/build
> +make[2]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/libwebsockets-3.2.0/CMakeFiles/CMakeTmp'
> +Building C object CMakeFiles/cmTC_06946.dir/CheckFunctionExists.c.o
> +/home/buildroot/autobuild/instance-2/output-1/host/bin/arm-linux-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabihf/sysroot -DKEYWORD=__inline  -Wall -Wsign-compare -Wuninitialized -Werror  -Wundef  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os  -DCHECK_FUNCTION_EXISTS=SSL_CTX_set1_param -pthread  -DNDEBUG   -o CMakeFiles/cmTC_06946.dir/CheckFunctionExists.c.o   -c /home/buildroot/autobuild/instance-2/output-1/host/share/cmake-3.15/Modules/CheckFunctionExists.c
> +Linking C executable cmTC_06946
> +/home/buildroot/autobuild/instance-2/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_06946.dir/link.txt --verbose=1
> +/home/buildroot/autobuild/instance-2/output-1/host/bin/arm-linux-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabihf/sysroot -Wall -Wsign-compare -Wuninitialized -Werror  -Wundef  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os  -DCHECK_FUNCTION_EXISTS=SSL_CTX_set1_param -pthread  -DNDEBUG    CMakeFiles/cmTC_06946.dir/CheckFunctionExists.c.o  -o cmTC_06946 /home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabihf/sysroot/usr/lib/libssl.so /home/buildroot/autobuild/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabihf/sysroot/usr/lib/libcrypto.so -lssl -lcrypto -lm -lcap
> +/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabihf/8.3.0/../../../../arm-buildroot-linux-uclibcgnueabihf/bin/ld: cannot find -lpthread
> +collect2: error: ld returned 1 exit status
> +CMakeFiles/cmTC_06946.dir/build.make:88: recipe for target 'cmTC_06946' failed

I am confused by the relationship between the OpenSSL detection issue
and the pthread problem.

> + - http://autobuild.buildroot.org/results/6186b4718db285edadf7203d00ed72f8d76a31e4
> +
> +Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

Was this patch submitted upstream ?

> +-set(CMAKE_REQUIRED_FLAGS "-pthread")	
> +-CHECK_C_SOURCE_COMPILES("#define _GNU_SOURCE 
> +-	#include <pthread.h> 
> +-	int main(void) { 
> +-		pthread_t th = 0;
> +-		pthread_setname_np(th, NULL);
> +-		return 0;
> +-	}" LWS_HAS_PTHREAD_SETNAME_NP)
> +-
> +-CHECK_C_SOURCE_COMPILES("#include <stddef.h>
> +-	#include <getopt.h> 
> +-	int main(void) { 
> +-		void *p = (void *)getopt_long;
> +-		return p != NULL;
> +-	}" LWS_HAS_GETOPT_LONG)
> ++if (LWS_HAVE_PTHREAD_H) 
> ++	set(CMAKE_REQUIRED_FLAGS "-pthread")	
> ++	CHECK_C_SOURCE_COMPILES("#define _GNU_SOURCE 
> ++		#include <pthread.h> 
> ++		int main(void) { 
> ++			pthread_t th = 0;
> ++			pthread_setname_np(th, NULL);
> ++			return 0;
> ++		}" LWS_HAS_PTHREAD_SETNAME_NP)
> ++
> ++	CHECK_C_SOURCE_COMPILES("#include <stddef.h>
> ++		#include <getopt.h> 
> ++		int main(void) { 
> ++			void *p = (void *)getopt_long;
> ++			return p != NULL;
> ++		}" LWS_HAS_GETOPT_LONG)

Why is the getopt_long check moved into the LWS_HAVE_PTHREAD_H
condition? It seems unrelated.

> ++endif()

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com