Build error in debian jessie

[parkmino]

myMPD version: 6.0.1

Describe the bug

Tried to build debian jessie for armel, however it failed with the following message.

[100%] Building C object CMakeFiles/mympd.dir/src/cert.c.o
/root/myMPD-6.0.1/src/cert.c: In function 'add_extension':
/root/myMPD-6.0.1/src/cert.c:301:62: error: passing argument 4 of 'X509V3_EXT_conf_nid' discards 'const' qualifier from pointer target type [-Werror]
     X509_EXTENSION *ex = X509V3_EXT_conf_nid(NULL, ctx, nid, value);
                                                              ^
In file included from /root/myMPD-6.0.1/src/cert.c:23:0:
/usr/include/openssl/x509v3.h:616:17: note: expected 'char *' but argument is of type 'const char *'
 X509_EXTENSION *X509V3_EXT_conf_nid(LHASH_OF(CONF_VALUE) *conf,
                 ^
/root/myMPD-6.0.1/src/cert.c: In function 'generate_selfsigned_cert':
/root/myMPD-6.0.1/src/cert.c:422:81: error: passing argument 4 of 'X509V3_EXT_conf_nid' discards 'const' qualifier from pointer target type [-Werror]
     X509_EXTENSION *ex = X509V3_EXT_conf_nid(NULL, &ctx, NID_basic_constraints, "CA:true");
                                                                                 ^
In file included from /root/myMPD-6.0.1/src/cert.c:23:0:
/usr/include/openssl/x509v3.h:616:17: note: expected 'char *' but argument is of type 'const char *'
 X509_EXTENSION *X509V3_EXT_conf_nid(LHASH_OF(CONF_VALUE) *conf,
                 ^
cc1: all warnings being treated as errors
CMakeFiles/mympd.dir/build.make:2101: recipe for target 'CMakeFiles/mympd.dir/src/cert.c.o' failed
make[2]: *** [CMakeFiles/mympd.dir/src/cert.c.o] Error 1
CMakeFiles/Makefile2:60: recipe for target 'CMakeFiles/mympd.dir/all' failed
make[1]: *** [CMakeFiles/mympd.dir/all] Error 2
Makefile:117: recipe for target 'all' failed
make: *** [all] Error 2

[parkmino]

I build it successfully with ENABLE_SSL="OFF". Is it related to the version of openssl ?

[jcorporation]

Yes, it seems the openssl version in jessy is to old. There are API changes in openssl 1.1.0 and jessie ships a 1.0.x version.

[parkmino]

ENABLE_SSL="OFF" does not work for 'pkgdebian' option. Is there any work around?

[jcorporation]

All packaging options don‘t respect the environment variables. But removing the libssl-dev package should do the trick.

I think the best way is to improve the cmake script.

[jcorporation]

Check openssl version >= 1.1.0

if(<variable|string> VERSION_GREATER <variable|string>) Component-wise integer version number comparison (version format is major[.minor[.patch[.tweak]]]).

OPENSSL_VERSION This is set to $major.$minor.$revision$patch (e.g. 0.9.8s).

[BenjaminDebeerst]

I also stumbled upon this while trying to compile on an old debian, and I worked around it by having warnings not treated as errors, by removing the -Werror flags here: https://github.com/jcorporation/myMPD/blob/master/CMakeLists.txt#L120-L123

That's not a great solution in general, but allowed me to compile and test quickly.

[parkmino]

This work around works, thanks!

I also stumbled upon this while trying to compile on an old debian, and I worked around it by having warnings not treated as errors, by removing the -Werror flags here: https://github.com/jcorporation/myMPD/blob/master/CMakeLists.txt#L120-L123

That's not a great solution in general, but allowed me to compile and test quickly.

[jcorporation]

Works SSL with this hack or you don‘t enabled ssl anyway?

[parkmino]

It builds showing the error message with ssl enabled.

[jcorporation]

My question was: with this hack, runs the binary with ssl flawless?

[parkmino]

Yes, it shows the error message though.

[BenjaminDebeerst]

Same here, I just went back to that test setup and enabled SSL and it works. The browser shows the "unknown issuer" SSL error warning, but I guess that is expected.

[jcorporation]

The "unknown issuer" warning is ok, if you not imported the myMPD CA. The build should now disable SSL if OpenSSL version is smaller than 1.1.0. Can you give it a try?

[BenjaminDebeerst]

No, this doesn't seem to work entirely, I just built from the devel branch (6a80ea2f0), yielding first this (and I was already writing that it worked :-) ):

Searching for openssl
-- Found OpenSSL: /usr/lib/arm-linux-gnueabihf/libssl.so;/usr/lib/arm-linux-gnueabihf/libcrypto.so (found version "1.0.1t") 
Openssl is disabled

But the build later fails with the same warnings as reported above.

[jcorporation]

Last commit should fix the issue definitely. Don't hesitate to reopen the issue, if it don't works for you.

[parkmino]

Yes, it now builds flawlessly. Thanks !