Segfault [contains backtrace] [links to PR fix]

[xloem]

Bug Description
witness_node segfaults on launch apparently due to dereference of null pointer in libraries/fc

$ gdb --args programs/witness_node/witness_node --help
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Reading symbols from programs/witness_node/witness_node...
done
(gdb) run
Starting program: /shared/src/bitshares-core/build/programs/witness_node/witness_node --help
Missing separate debuginfos, use: debuginfo-install glibc-2.17-292.el7.x86_64
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff696cef3 in std::string::empty() const () from /lib64/libstdc++.so.6
Missing separate debuginfos, use: debuginfo-install cyrus-sasl-lib-2.1.26-23.el7.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-37.el7_7.2.x86_64 libcom_err-1.42.9-16.el7.x86_64 libcurl-7.29.0-54.el7.x86_64 libgcc-4.8.5-39.el7.x86_64 libidn-1.28-4.el7.x86_64 libselinux-2.5-14.1.el7.x86_64 libssh2-1.8.0-3.el7.x86_64 libstdc++-4.8.5-39.el7.x86_64 nspr-4.21.0-1.el7.x86_64 nss-3.44.0-4.el7.x86_64 nss-softokn-freebl-3.44.0-5.el7.x86_64 nss-util-3.44.0-3.el7.x86_64 openldap-2.4.44-21.el7_6.x86_64 openssl-libs-1.0.2k-19.el7.x86_64 pcre-8.32-17.el7.x86_64 zlib-1.2.7-18.el7.x86_64
(gdb) bt
#0  0x00007ffff696cef3 in std::string::empty() const () from /lib64/libstdc++.so.6
#1  0x00000000094bf0ca in boost::filesystem::path::empty (this=0xf1aeae0 <fc::openssl_scope::_configurationFilePath>) at /usr/local/include/boost/filesystem/path.hpp:515
#2  0x000000000961a413 in fc::openssl_scope::openssl_scope (this=0xf1aeb08 <fc::init_openssl()::ossl>) at /home/user/src/bitshares-core/libraries/fc/src/crypto/openssl.cpp:22
#3  0x0000000009619ddf in fc::init_openssl () at /home/user/src/bitshares-core/libraries/fc/src/crypto/openssl.cpp:63
#4  0x00000000094f567a in fc::ecc::detail::_init_lib () at /home/user/src/bitshares-core/libraries/fc/src/crypto/elliptic_secp256k1.cpp:32
#5  0x00000000094f9c9e in fc::ecc::detail::public_key_impl::public_key_impl (this=0x7fffffffdc90) at /home/user/src/bitshares-core/libraries/fc/src/crypto/elliptic_secp256k1.cpp:41
#6  0x00000000094f9b90 in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/user/src/bitshares-core/libraries/fc/src/crypto/elliptic_secp256k1.cpp:63
#7  0x00000000094f9bfc in _GLOBAL__sub_I_elliptic_secp256k1.cpp(void) () at /home/user/src/bitshares-core/libraries/fc/src/crypto/elliptic_secp256k1.cpp:306
#8  0x000000000b30434d in __libc_csu_init ()
#9  0x00007ffff5fec4d5 in __libc_start_main () from /lib64/libc.so.6
#10 0x000000000884bf65 in _start ()
(gdb) up 2
#2  0x000000000961a413 in fc::openssl_scope::openssl_scope (this=0xf1aeb08 <fc::init_openssl()::ossl>) at /home/user/src/bitshares-core/libraries/fc/src/crypto/openssl.cpp:22
22                if(boostPath.empty() == false)
(gdb) list
17             {
18                ERR_load_crypto_strings(); 
19                OpenSSL_add_all_algorithms();
20
21                const boost::filesystem::path& boostPath = _configurationFilePath;
22                if(boostPath.empty() == false)
23                {
24                  std::string varSetting("OPENSSL_CONF=");
25                  varSetting += _configurationFilePath.to_native_ansi_path();
26      #if defined(WIN32)
(gdb) break 21
Breakpoint 1 at 0x961a3f4: file /home/user/src/bitshares-core/libraries/fc/src/crypto/openssl.cpp, line 21.
(gdb) run
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /shared/src/bitshares-core/build/programs/witness_node/witness_node --help
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Breakpoint 1, fc::openssl_scope::openssl_scope (this=0xf1aeb08 <fc::init_openssl()::ossl>) at /home/user/src/bitshares-core/libraries/fc/src/crypto/openssl.cpp:21
21                const boost::filesystem::path& boostPath = _configurationFilePath;
(gdb) s
fc::path::operator boost::filesystem::path& (this=0xf1aeae0 <fc::openssl_scope::_configurationFilePath>) at /home/user/src/bitshares-core/libraries/fc/src/filesystem.cpp:90
90          return *_p;
(gdb) p _p
$1 = {_store = '\000' <repeats 31 times>}
(gdb) p (bool)_p
$2 = false

Host Environment
Please provide details about the host environment. Much of this information can be found running: witness_node --version.

• Host OS: Red Hat Enterprise Linux Workstation release 7.7 (Maipo)
• Host Physical RAM 16GB
• BitShares Version: 5.0.0
• OpenSSL Version: 1.1.1h-dev
• Boost Version: 1.67.0

CORE TEAM TASK LIST

• Evaluate / Prioritize Bug Report
• Refine User Stories / Requirements
• Define Test Cases
• Design / Develop Solution
• Perform QA/Testing
• Update Documentation

[abitmore]

TODO: bump FC to include bitshares/bitshares-fc#211.

[abitmore]

Fixed by bitshares/bitshares-fc#211 and #2288.