[MESOS-9353] libprocess triggers deprecation warnings when built against openssl 1.1.

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.8.0
• Fix Version/s: 1.9.0
• Component/s: build, libprocess
• Labels: OpenSSL build deprecation libprocess warnings
• Assignee: Till Toenshoff
• Reporter: Till Toenshoff
• Created: 24/Oct/18 14:41
• Updated: 21/Aug/19 12:05
• Resolved: 21/Aug/19 12:05

Description

When building libprocess against libevent and openssl 1.1, the results are deprecation warnings;

../3rdparty/libprocess/src/openssl.cpp:764:39: warning: 'ASN1_STRING_data' is deprecated [-Wdeprecated-declarations]
              reinterpret_cast<char*>(ASN1_STRING_data(
                                      ^
/usr/include/openssl/asn1.h:553:1: note: 'ASN1_STRING_data' has been explicitly marked deprecated here
DEPRECATEDIN_1_1_0(unsigned char *ASN1_STRING_data(ASN1_STRING *x))
^
/usr/include/openssl/opensslconf-x86_64.h:122:34: note: expanded from macro 'DEPRECATEDIN_1_1_0'
# define DEPRECATEDIN_1_1_0(f)   DECLARE_DEPRECATED(f)
                                 ^
/usr/include/openssl/opensslconf-x86_64.h:96:56: note: expanded from macro 'DECLARE_DEPRECATED'
#    define DECLARE_DEPRECATED(f)    f __attribute__ ((deprecated));
                                                       ^

These warnings are benign and can get ignored for now, as long as no warning to error escalation is active. For successful builds we need to activate disable-werror for autotools - cmake builds do not escalate warnings to errors by default.

We should still fix those warnings, likely by adapting towards openssl1.1 via preprocessor/define gates like;

#if OPENSSL_VERSION_NUMBER < 0x10100000L
  [leave code as is]
#else
  [add variant that does not rely on deprecated ASN1_STRING_data]
#endif