Merge #15382: util: add RunCommandParseJSON

31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0 [util] add RunCommandParseJSON (Sjors Provoost)
c17f54ee535faaedf9033717403e1f775b5f1530 [ci] use boost::process (Sjors Provoost)
32128ba682033560d6eb2e4848a9f77a842016d2 [doc] include Doxygen comments for HAVE_BOOST_PROCESS (Sjors Provoost)
3c84d85f7d218fa27e9343c5cd1a55e519218980 [build] msvc: add boost::process (Sjors Provoost)
c47e4bbf0b44f2de1278f9538124ec98ee0815bb [build] make boost-process opt-in (Sjors Provoost)
929cda5470f98d1ef85c05b1cad4e2fb9227e3b0 configure: add ax_boost_process (Sjors Provoost)
8314c23d7b39fc36dde8b40b03b6efbe96f85698 [depends] boost: patch unused variable in boost_process (Sjors Provoost)

Pull request description:

  Prerequisite for external signer support in #16546. Big picture overview in [this gist](https://gist.github.com/Sjors/29d06728c685e6182828c1ce9b74483d).

  This adds a new dependency [boost process](https://github.com/boostorg/process/tree/boost-1.64.0). This is part of Boost since 1.64 which is part of `depends`. Because the minimum Boost version is 1.47, this functionality is skipped for older versions of Boost.

  Use `./configure --with-boost-process` to opt in, which checks for the presence of Boost::Process.

  We add `UniValue runCommandParseJSON(const std::string& strCommand)` to `system.{h,cpp}` which calls an arbitrary command and processes the JSON returned by it. This is currently only called by the test suite.

  ~For testing purposes this adds a new regtest-only RPC method `runcommand`, as well as `test/mocks/command.py` used by functional tests.~ (this is no longer the case)

  TODO:
  - [ ] review boost process in #15440

ACKs for top commit:
  achow101:
    ACK 31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0
  hebasto:
    re-ACK 31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0, only rebased (verified with `git range-diff`) and removed an unintentional tab character since the [previous](https://github.com/bitcoin/bitcoin/pull/15382#pullrequestreview-458371035) review.
  meshcollider:
    Very light utACK 31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0, although I am not very confident with build stuff.
  promag:
    Code review ACK 31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0, don't mind the nit.
  ryanofsky:
    Code review ACK 31cf68a3ad1f0a5537c8419e2912b55fbfb88fa0. I left some comments below that could be ignored or followed up later. The current change is clean and comprehensive.

Tree-SHA512: c506e747014b263606e1f538ed4624a8ad7bcf4e025cb700c12cc5739964e254dc04a2bbb848996b170e2ccec3fbfa4fe9e2b3976b191222cfb82fc3e6ab182d

24 files changed, 295 insertions, 15 deletions

diff --git a/.travis.yml b/.travis.yml
index f9932cfaca..f1cee7133f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -80,7 +80,7 @@ jobs:
         QEMU_USER_CMD=""
 
     - stage: test
-      name: 'Win64  [GOAL: deploy]  [unit tests, no gui, no functional tests]'
+      name: 'Win64  [GOAL: deploy]  [unit tests, no gui, no boost::process, no functional tests]'
       env: >-
         FILE_ENV="./ci/test/00_setup_env_win64.sh"
 
diff --git a/build-aux/m4/ax_boost_process.m4 b/build-aux/m4/ax_boost_process.m4
new file mode 100644
index 0000000000..5d20e67464
--- /dev/null
+++ b/build-aux/m4/ax_boost_process.m4
@@ -0,0 +1,121 @@
+# ===========================================================================
+#     https://www.gnu.org/software/autoconf-archive/ax_boost_process.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_BOOST_PROCESS
+#
+# DESCRIPTION
+#
+#   Test for Process library from the Boost C++ libraries. The macro
+#   requires a preceding call to AX_BOOST_BASE. Further documentation is
+#   available at <http://randspringer.de/boost/index.html>.
+#
+#   This macro calls:
+#
+#     AC_SUBST(BOOST_PROCESS_LIB)
+#
+#   And sets:
+#
+#     HAVE_BOOST_PROCESS
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Thomas Porschberg <thomas@randspringer.de>
+#   Copyright (c) 2008 Michael Tindal
+#   Copyright (c) 2008 Daniel Casimiro <dan.casimiro@gmail.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 2
+
+AC_DEFUN([AX_BOOST_PROCESS],
+[
+	AC_ARG_WITH([boost-process],
+	AS_HELP_STRING([--with-boost-process@<:@=special-lib@:>@],
+                   [use the Process library from boost - it is possible to specify a certain library for the linker
+                        e.g. --with-boost-process=boost_process-gcc-mt ]),
+        [
+        if test "$withval" = "no"; then
+			want_boost_process="no"
+        elif test "$withval" = "yes"; then
+            want_boost_process="yes"
+            ax_boost_user_process_lib=""
+        else
+		    want_boost_process="yes"
+		ax_boost_user_process_lib="$withval"
+		fi
+        ],
+        [want_boost_process="yes"]
+	)
+
+	if test "x$want_boost_process" = "xyes"; then
+        AC_REQUIRE([AC_PROG_CC])
+        AC_REQUIRE([AC_CANONICAL_BUILD])
+		CPPFLAGS_SAVED="$CPPFLAGS"
+		CPPFLAGS="$CPPFLAGS $BOOST_CPPFLAGS"
+		export CPPFLAGS
+
+		LDFLAGS_SAVED="$LDFLAGS"
+		LDFLAGS="$LDFLAGS $BOOST_LDFLAGS"
+		export LDFLAGS
+
+        AC_CACHE_CHECK(whether the Boost::Process library is available,
+					   ax_cv_boost_process,
+        [AC_LANG_PUSH([C++])
+			 CXXFLAGS_SAVE=$CXXFLAGS
+			 CXXFLAGS=
+
+             AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <boost/process.hpp>]],
+                [[boost::process::child* child = new boost::process::child; delete child;]])],
+                ax_cv_boost_process=yes, ax_cv_boost_process=no)
+			 CXXFLAGS=$CXXFLAGS_SAVE
+             AC_LANG_POP([C++])
+		])
+		if test "x$ax_cv_boost_process" = "xyes"; then
+			AC_SUBST(BOOST_CPPFLAGS)
+
+			AC_DEFINE(HAVE_BOOST_PROCESS,,[define if the Boost::Process library is available])
+            BOOSTLIBDIR=`echo $BOOST_LDFLAGS | sed -e 's/@<:@^\/@:>@*//'`
+
+			LDFLAGS_SAVE=$LDFLAGS
+            if test "x$ax_boost_user_process_lib" = "x"; then
+                for libextension in `ls -r $BOOSTLIBDIR/libboost_process* 2>/dev/null | sed 's,.*/lib,,' | sed 's,\..*,,'` ; do
+                     ax_lib=${libextension}
+				    AC_CHECK_LIB($ax_lib, exit,
+                                 [BOOST_PROCESS_LIB="-l$ax_lib"; AC_SUBST(BOOST_PROCESS_LIB) link_process="yes"; break],
+                                 [link_process="no"])
+				done
+                if test "x$link_process" != "xyes"; then
+                for libextension in `ls -r $BOOSTLIBDIR/boost_process* 2>/dev/null | sed 's,.*/,,' | sed -e 's,\..*,,'` ; do
+                     ax_lib=${libextension}
+				    AC_CHECK_LIB($ax_lib, exit,
+                                 [BOOST_PROCESS_LIB="-l$ax_lib"; AC_SUBST(BOOST_PROCESS_LIB) link_process="yes"; break],
+                                 [link_process="no"])
+				done
+                fi
+
+            else
+               for ax_lib in $ax_boost_user_process_lib boost_process-$ax_boost_user_process_lib; do
+				      AC_CHECK_LIB($ax_lib, exit,
+                                   [BOOST_PROCESS_LIB="-l$ax_lib"; AC_SUBST(BOOST_PROCESS_LIB) link_process="yes"; break],
+                                   [link_process="no"])
+                  done
+
+            fi
+            if test "x$ax_lib" = "x"; then
+                AC_MSG_ERROR(Could not find a version of the Boost::Process library!)
+            fi
+			if test "x$link_process" = "xno"; then
+				AC_MSG_ERROR(Could not link against $ax_lib !)
+			fi
+		fi
+
+		CPPFLAGS="$CPPFLAGS_SAVED"
+	LDFLAGS="$LDFLAGS_SAVED"
+	fi
+])
diff --git a/build_msvc/bitcoin_config.h b/build_msvc/bitcoin_config.h
index fbbe1a2156..9d0b50a0b4 100644
--- a/build_msvc/bitcoin_config.h
+++ b/build_msvc/bitcoin_config.h
@@ -47,6 +47,9 @@
 /* define if the Boost::Filesystem library is available */
 #define HAVE_BOOST_FILESYSTEM /**/
 
+/* define if the Boost::Process library is available */
+#define HAVE_BOOST_PROCESS /**/
+
 /* define if the Boost::System library is available */
 #define HAVE_BOOST_SYSTEM /**/
 
diff --git a/build_msvc/vcpkg-packages.txt b/build_msvc/vcpkg-packages.txt
index 307f295f08..edce8576c3 100644
--- a/build_msvc/vcpkg-packages.txt
+++ b/build_msvc/vcpkg-packages.txt
@@ -1 +1 @@
-berkeleydb boost-filesystem boost-multi-index boost-signals2 boost-test boost-thread libevent[thread] zeromq double-conversion
\ No newline at end of file
+berkeleydb boost-filesystem boost-multi-index boost-process boost-signals2 boost-test boost-thread libevent[thread] zeromq double-conversion
diff --git a/ci/test/00_setup_env_arm.sh b/ci/test/00_setup_env_arm.sh
index b70a581532..2e445c126d 100644
--- a/ci/test/00_setup_env_arm.sh
+++ b/ci/test/00_setup_env_arm.sh
@@ -25,4 +25,4 @@ export RUN_FUNCTIONAL_TESTS=true
 export GOAL="install"
 # -Wno-psabi is to disable ABI warnings: "note: parameter passing for argument of type ... changed in GCC 7.1"
 # This could be removed once the ABI change warning does not show up by default
-export BITCOIN_CONFIG="--enable-glibc-back-compat --enable-reduce-exports CXXFLAGS=-Wno-psabi --enable-werror"
+export BITCOIN_CONFIG="--enable-glibc-back-compat --enable-reduce-exports CXXFLAGS=-Wno-psabi --enable-werror --with-boost-process"
diff --git a/ci/test/00_setup_env_i686_centos.sh b/ci/test/00_setup_env_i686_centos.sh
index 5688799f9e..e58003ab19 100644
--- a/ci/test/00_setup_env_i686_centos.sh
+++ b/ci/test/00_setup_env_i686_centos.sh
@@ -11,5 +11,5 @@ export CONTAINER_NAME=ci_i686_centos_7
 export DOCKER_NAME_TAG=centos:7
 export DOCKER_PACKAGES="gcc-c++ glibc-devel.x86_64 libstdc++-devel.x86_64 glibc-devel.i686 libstdc++-devel.i686 ccache libtool make git python3 python36-zmq which patch lbzip2 dash"
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-reduce-exports"
+export BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-reduce-exports --with-boost-process"
 export CONFIG_SHELL="/bin/dash"
diff --git a/ci/test/00_setup_env_mac.sh b/ci/test/00_setup_env_mac.sh
index 7ec66eeb4f..b62f1603f4 100644
--- a/ci/test/00_setup_env_mac.sh
+++ b/ci/test/00_setup_env_mac.sh
@@ -14,4 +14,4 @@ export XCODE_BUILD_ID=11C505
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false
 export GOAL="deploy"
-export BITCOIN_CONFIG="--with-gui --enable-reduce-exports --enable-werror"
+export BITCOIN_CONFIG="--with-gui --enable-reduce-exports --enable-werror --with-boost-process"
diff --git a/ci/test/00_setup_env_mac_host.sh b/ci/test/00_setup_env_mac_host.sh
index b8a9ccaae5..5fb127b762 100644
--- a/ci/test/00_setup_env_mac_host.sh
+++ b/ci/test/00_setup_env_mac_host.sh
@@ -10,7 +10,7 @@ export HOST=x86_64-apple-darwin16
 export DOCKER_NAME_TAG=ubuntu:18.04  # Check that bionic can cross-compile to macos (bionic is used in the gitian build as well)
 export PIP_PACKAGES="zmq"
 export GOAL="install"
-export BITCOIN_CONFIG="--with-gui --enable-reduce-exports --enable-werror"
+export BITCOIN_CONFIG="--with-gui --enable-reduce-exports --enable-werror --with-boost-process"
 export NO_DEPENDS=1
 export OSX_SDK=""
 export CCACHE_SIZE=300M
diff --git a/ci/test/00_setup_env_native_asan.sh b/ci/test/00_setup_env_native_asan.sh
index d57c673069..5995964f17 100644
--- a/ci/test/00_setup_env_native_asan.sh
+++ b/ci/test/00_setup_env_native_asan.sh
@@ -12,4 +12,4 @@ export DOCKER_NAME_TAG=ubuntu:20.04
 export NO_DEPENDS=1
 export TEST_RUNNER_EXTRA="--timeout-factor=4"  # Increase timeout because sanitizers slow down
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-zmq --with-incompatible-bdb --with-gui=qt5 CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' --with-sanitizers=address,integer,undefined CC=clang CXX=clang++"
+export BITCOIN_CONFIG="--enable-zmq --with-incompatible-bdb --with-gui=qt5 CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' --with-sanitizers=address,integer,undefined CC=clang CXX=clang++ --with-boost-process"
diff --git a/ci/test/00_setup_env_native_fuzz.sh b/ci/test/00_setup_env_native_fuzz.sh
index 31f437f0e8..a32de4a6b5 100644
--- a/ci/test/00_setup_env_native_fuzz.sh
+++ b/ci/test/00_setup_env_native_fuzz.sh
@@ -14,5 +14,5 @@ export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false
 export RUN_FUZZ_TESTS=true
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-fuzz --with-sanitizers=fuzzer,address,undefined CC=clang CXX=clang++"
+export BITCOIN_CONFIG="--enable-fuzz --with-sanitizers=fuzzer,address,undefined CC=clang CXX=clang++ --with-boost-process"
 export CCACHE_SIZE=200M
diff --git a/ci/test/00_setup_env_native_multiprocess.sh b/ci/test/00_setup_env_native_multiprocess.sh
index 786f0f927f..522a5d9fc2 100644
--- a/ci/test/00_setup_env_native_multiprocess.sh
+++ b/ci/test/00_setup_env_native_multiprocess.sh
@@ -11,5 +11,5 @@ export DOCKER_NAME_TAG=ubuntu:20.04
 export PACKAGES="cmake python3"
 export DEP_OPTS="MULTIPROCESS=1"
 export GOAL="install"
-export BITCOIN_CONFIG=""
+export BITCOIN_CONFIG="--with-boost-process"
 export TEST_RUNNER_ENV="BITCOIND=bitcoin-node"
diff --git a/ci/test/00_setup_env_native_nowallet.sh b/ci/test/00_setup_env_native_nowallet.sh
index 1a0b14b62b..0a09bfe230 100644
--- a/ci/test/00_setup_env_native_nowallet.sh
+++ b/ci/test/00_setup_env_native_nowallet.sh
@@ -11,4 +11,4 @@ export DOCKER_NAME_TAG=ubuntu:16.04  # Use xenial to have one config run the tes
 export PACKAGES="python3-zmq clang-3.8 llvm-3.8"  # Use clang-3.8 to test C++11 compatibility, see doc/dependencies.md
 export DEP_OPTS="NO_WALLET=1"
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-glibc-back-compat --enable-reduce-exports CC=clang-3.8 CXX=clang++-3.8"
+export BITCOIN_CONFIG="--enable-glibc-back-compat --enable-reduce-exports CC=clang-3.8 CXX=clang++-3.8 --with-boost-process"
diff --git a/ci/test/00_setup_env_native_qt5.sh b/ci/test/00_setup_env_native_qt5.sh
index 6e2ff729a2..f9d869b4fd 100644
--- a/ci/test/00_setup_env_native_qt5.sh
+++ b/ci/test/00_setup_env_native_qt5.sh
@@ -16,4 +16,4 @@ export RUN_UNIT_TESTS_SEQUENTIAL="true"
 export RUN_UNIT_TESTS="false"
 export GOAL="install"
 export PREVIOUS_RELEASES_TO_DOWNLOAD="v0.15.2 v0.16.3 v0.17.1 v0.18.1 v0.19.1"
-export BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-glibc-back-compat --enable-reduce-exports --enable-c++17 --enable-debug CFLAGS=\"-g0 -O2 -funsigned-char\" CXXFLAGS=\"-g0 -O2 -funsigned-char\""
+export BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-glibc-back-compat --enable-reduce-exports --enable-c++17 --enable-debug CFLAGS=\"-g0 -O2 -funsigned-char\" CXXFLAGS=\"-g0 -O2 -funsigned-char\" --with-boost-process"
diff --git a/ci/test/00_setup_env_native_tsan.sh b/ci/test/00_setup_env_native_tsan.sh
index 5695c43ec3..fc18483425 100644
--- a/ci/test/00_setup_env_native_tsan.sh
+++ b/ci/test/00_setup_env_native_tsan.sh
@@ -12,4 +12,4 @@ export PACKAGES="clang llvm libc++abi-dev libc++-dev python3-zmq"
 export DEP_OPTS="CC=clang CXX='clang++ -stdlib=libc++'"
 export TEST_RUNNER_EXTRA="--exclude feature_block --timeout-factor=4"  # Increase timeout because sanitizers slow down. Low memory on Travis machines, exclude feature_block.
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-zmq --with-gui=no CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' CXXFLAGS='-g' --with-sanitizers=thread CC=clang CXX='clang++ -stdlib=libc++'"
+export BITCOIN_CONFIG="--enable-zmq --with-gui=no CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' CXXFLAGS='-g' --with-sanitizers=thread CC=clang CXX='clang++ -stdlib=libc++' --with-boost-process"
diff --git a/ci/test/00_setup_env_s390x.sh b/ci/test/00_setup_env_s390x.sh
index c180d023de..fe330920d0 100644
--- a/ci/test/00_setup_env_s390x.sh
+++ b/ci/test/00_setup_env_s390x.sh
@@ -22,4 +22,4 @@ export DOCKER_NAME_TAG="debian:buster"
 export RUN_UNIT_TESTS=true
 export RUN_FUNCTIONAL_TESTS=true
 export GOAL="install"
-export BITCOIN_CONFIG="--enable-reduce-exports --with-incompatible-bdb"
+export BITCOIN_CONFIG="--enable-reduce-exports --with-incompatible-bdb --with-boost-process"
diff --git a/ci/test/00_setup_env_win64.sh b/ci/test/00_setup_env_win64.sh
index eb8b870dd6..2b351dff6d 100644
--- a/ci/test/00_setup_env_win64.sh
+++ b/ci/test/00_setup_env_win64.sh
@@ -13,4 +13,4 @@ export PACKAGES="python3 nsis g++-mingw-w64-x86-64 wine-binfmt wine64"
 export RUN_FUNCTIONAL_TESTS=false
 export RUN_SECURITY_TESTS="true"
 export GOAL="deploy"
-export BITCOIN_CONFIG="--enable-reduce-exports --disable-gui-tests"
+export BITCOIN_CONFIG="--enable-reduce-exports --disable-gui-tests --without-boost-process"
diff --git a/configure.ac b/configure.ac
index f11f2b2059..013e68a319 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1191,6 +1191,9 @@ AX_BOOST_SYSTEM
 AX_BOOST_FILESYSTEM
 AX_BOOST_THREAD
 
+dnl Opt-in to boost-process
+AS_IF([ test x$with_boost_process != x ], [ AX_BOOST_PROCESS ], [ ax_cv_boost_process=no ] )
+
 dnl Boost 1.56 through 1.62 allow using std::atomic instead of its own atomic
 dnl counter implementations. In 1.63 and later the std::atomic approach is default.
 m4_pattern_allow(DBOOST_AC_USE_STD_ATOMIC) dnl otherwise it's treated like a macro
@@ -1683,6 +1686,7 @@ esac
 
 echo
 echo "Options used to compile and link:"
+echo "  boost process = $ax_cv_boost_process"
 echo "  multiprocess  = $build_multiprocess"
 echo "  with wallet   = $enable_wallet"
 echo "  with gui / qt = $bitcoin_enable_qt"
diff --git a/depends/packages/boost.mk b/depends/packages/boost.mk
index 3a7e605b4f..4f6b543aff 100644
--- a/depends/packages/boost.mk
+++ b/depends/packages/boost.mk
@@ -31,7 +31,9 @@ $(package)_cxxflags_linux=-fPIC
 $(package)_cxxflags_android=-fPIC
 endef
 
+# Fix unused variable in boost_process, can be removed after upgrading to 1.72
 define $(package)_preprocess_cmds
+  sed -i.old "s/int ret_sig = 0;//" boost/process/detail/posix/wait_group.hpp && \
   echo "using $($(package)_toolset_$(host_os)) : : $($(package)_cxx) : <cxxflags>\"$($(package)_cxxflags) $($(package)_cppflags)\" <linkflags>\"$($(package)_ldflags)\" <archiver>\"$($(package)_archiver_$(host_os))\" <striper>\"$(host_STRIP)\"  <ranlib>\"$(host_RANLIB)\" <rc>\"$(host_WINDRES)\" : ;" > user-config.jam
 endef
 
diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
index 7e307ab7c8..2f79168212 100644
--- a/doc/Doxyfile.in
+++ b/doc/Doxyfile.in
@@ -2073,7 +2073,7 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             =
+PREDEFINED             = HAVE_BOOST_PROCESS
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index b961f8d5b9..085ebdcb8e 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -265,6 +265,7 @@ BITCOIN_TESTS =\
   test/skiplist_tests.cpp \
   test/streams_tests.cpp \
   test/sync_tests.cpp \
+  test/system_tests.cpp \
   test/util_threadnames_tests.cpp \
   test/timedata_tests.cpp \
   test/torcontrol_tests.cpp \
diff --git a/src/test/system_tests.cpp b/src/test/system_tests.cpp
new file mode 100644
index 0000000000..a55145c738
--- /dev/null
+++ b/src/test/system_tests.cpp
@@ -0,0 +1,95 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+//
+#include <test/util/setup_common.h>
+#include <util/system.h>
+#include <univalue.h>
+
+#ifdef HAVE_BOOST_PROCESS
+#include <boost/process.hpp>
+#endif // HAVE_BOOST_PROCESS
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(system_tests, BasicTestingSetup)
+
+// At least one test is required (in case HAVE_BOOST_PROCESS is not defined).
+// Workaround for https://github.com/bitcoin/bitcoin/issues/19128
+BOOST_AUTO_TEST_CASE(dummy)
+{
+    BOOST_CHECK(true);
+}
+
+#ifdef HAVE_BOOST_PROCESS
+
+bool checkMessage(const std::runtime_error& ex)
+{
+    // On Linux & Mac: "No such file or directory"
+    // On Windows: "The system cannot find the file specified."
+    const std::string what(ex.what());
+    BOOST_CHECK(what.find("file") != std::string::npos);
+    return true;
+}
+
+bool checkMessageFalse(const std::runtime_error& ex)
+{
+    BOOST_CHECK_EQUAL(ex.what(), std::string("RunCommandParseJSON error: process(false) returned 1: \n"));
+    return true;
+}
+
+bool checkMessageStdErr(const std::runtime_error& ex)
+{
+    const std::string what(ex.what());
+    BOOST_CHECK(what.find("RunCommandParseJSON error:") != std::string::npos);
+    return checkMessage(ex);
+}
+
+BOOST_AUTO_TEST_CASE(run_command)
+{
+    {
+        const UniValue result = RunCommandParseJSON("");
+        BOOST_CHECK(result.isNull());
+    }
+    {
+#ifdef WIN32
+        // Windows requires single quotes to prevent escaping double quotes from the JSON...
+        const UniValue result = RunCommandParseJSON("echo '{\"success\": true}'");
+#else
+        // ... but Linux and macOS echo a single quote if it's used
+        const UniValue result = RunCommandParseJSON("echo \"{\"success\": true}\"");
+#endif
+        BOOST_CHECK(result.isObject());
+        const UniValue& success = find_value(result, "success");
+        BOOST_CHECK(!success.isNull());
+        BOOST_CHECK_EQUAL(success.getBool(), true);
+    }
+    {
+        // An invalid command is handled by Boost
+        BOOST_CHECK_EXCEPTION(RunCommandParseJSON("invalid_command"), boost::process::process_error, checkMessage); // Command failed
+    }
+    {
+        // Return non-zero exit code, no output to stderr
+        BOOST_CHECK_EXCEPTION(RunCommandParseJSON("false"), std::runtime_error, checkMessageFalse);
+    }
+    {
+        // Return non-zero exit code, with error message for stderr
+        BOOST_CHECK_EXCEPTION(RunCommandParseJSON("ls nosuchfile"), std::runtime_error, checkMessageStdErr);
+    }
+    {
+        BOOST_REQUIRE_THROW(RunCommandParseJSON("echo \"{\""), std::runtime_error); // Unable to parse JSON
+    }
+    // Test std::in, except for Windows
+#ifndef WIN32
+    {
+        const UniValue result = RunCommandParseJSON("cat", "{\"success\": true}");
+        BOOST_CHECK(result.isObject());
+        const UniValue& success = find_value(result, "success");
+        BOOST_CHECK(!success.isNull());
+        BOOST_CHECK_EQUAL(success.getBool(), true);
+    }
+#endif
+}
+#endif // HAVE_BOOST_PROCESS
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/util/system.cpp b/src/util/system.cpp
index 8164e884b1..066cfe8892 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -6,6 +6,10 @@
 #include <sync.h>
 #include <util/system.h>
 
+#ifdef HAVE_BOOST_PROCESS
+#include <boost/process.hpp>
+#endif // HAVE_BOOST_PROCESS
+
 #include <chainparamsbase.h>
 #include <util/strencodings.h>
 #include <util/string.h>
@@ -1161,6 +1165,43 @@ void runCommand(const std::string& strCommand)
 }
 #endif
 
+#ifdef HAVE_BOOST_PROCESS
+UniValue RunCommandParseJSON(const std::string& str_command, const std::string& str_std_in)
+{
+    namespace bp = boost::process;
+
+    UniValue result_json;
+    bp::opstream stdin_stream;
+    bp::ipstream stdout_stream;
+    bp::ipstream stderr_stream;
+
+    if (str_command.empty()) return UniValue::VNULL;
+
+    bp::child c(
+        str_command,
+        bp::std_out > stdout_stream,
+        bp::std_err > stderr_stream,
+        bp::std_in < stdin_stream
+    );
+    if (!str_std_in.empty()) {
+        stdin_stream << str_std_in << std::endl;
+    }
+    stdin_stream.pipe().close();
+
+    std::string result;
+    std::string error;
+    std::getline(stdout_stream, result);
+    std::getline(stderr_stream, error);
+
+    c.wait();
+    const int n_error = c.exit_code();
+    if (n_error) throw std::runtime_error(strprintf("RunCommandParseJSON error: process(%s) returned %d: %s\n", str_command, n_error, error));
+    if (!result_json.read(result)) throw std::runtime_error("Unable to parse JSON: " + result);
+
+    return result_json;
+}
+#endif // HAVE_BOOST_PROCESS
+
 void SetupEnvironment()
 {
 #ifdef HAVE_MALLOPT_ARENA_MAX
diff --git a/src/util/system.h b/src/util/system.h
index 0bd14cc9ea..1df194ca84 100644
--- a/src/util/system.h
+++ b/src/util/system.h
@@ -37,6 +37,8 @@
 
 #include <boost/thread/condition_variable.hpp> // for boost::thread_interrupted
 
+class UniValue;
+
 // Application startup time (used for uptime calculation)
 int64_t GetStartupTime();
 
@@ -96,6 +98,16 @@ std::string ShellEscape(const std::string& arg);
 #if HAVE_SYSTEM
 void runCommand(const std::string& strCommand);
 #endif
+#ifdef HAVE_BOOST_PROCESS
+/**
+ * Execute a command which returns JSON, and parse the result.
+ *
+ * @param str_command The command to execute, including any arguments
+ * @param str_std_in string to pass to stdin
+ * @return parsed JSON
+ */
+UniValue RunCommandParseJSON(const std::string& str_command, const std::string& str_std_in="");
+#endif // HAVE_BOOST_PROCESS
 
 /**
  * Most paths passed as configuration arguments are treated as relative to
diff --git a/test/lint/lint-includes.sh b/test/lint/lint-includes.sh
index 611bd4a8c4..fde77aea2d 100755
--- a/test/lint/lint-includes.sh
+++ b/test/lint/lint-includes.sh
@@ -63,6 +63,7 @@ EXPECTED_BOOST_INCLUDES=(
     boost/optional.hpp
     boost/preprocessor/cat.hpp
     boost/preprocessor/stringize.hpp
+    boost/process.hpp
     boost/signals2/connection.hpp
     boost/signals2/optional_last_value.hpp
     boost/signals2/signal.hpp