cmake: Add introspection module

Co-authored-by: Cory Fields <cory-nospam-@coryfields.com>
Co-authored-by: Vasil Dimov <vd@FreeBSD.org>

4 files changed, 363 insertions, 0 deletions

diff --git a/cmake/bitcoin-config.h.in b/cmake/bitcoin-config.h.in
index 9811939f4f..6b8f5d713d 100644
--- a/cmake/bitcoin-config.h.in
+++ b/cmake/bitcoin-config.h.in
@@ -29,6 +29,75 @@
 /* Copyright year */
 #define COPYRIGHT_YEAR @COPYRIGHT_YEAR@
 
+/* Define to 1 if you have the declaration of `fork', and to 0 if you don't.
+   */
+#cmakedefine01 HAVE_DECL_FORK
+
+/* Define to 1 if you have the declaration of `freeifaddrs', and to 0 if you
+   don't. */
+#cmakedefine01 HAVE_DECL_FREEIFADDRS
+
+/* Define to 1 if you have the declaration of `getifaddrs', and to 0 if you
+   don't. */
+#cmakedefine01 HAVE_DECL_GETIFADDRS
+
+/* Define to 1 if you have the declaration of `pipe2', and to 0 if you don't.
+   */
+#cmakedefine01 HAVE_DECL_PIPE2
+
+/* Define to 1 if you have the declaration of `setsid', and to 0 if you don't.
+   */
+#cmakedefine01 HAVE_DECL_SETSID
+
+/* Define to 1 if fdatasync is available. */
+#cmakedefine HAVE_FDATASYNC 1
+
+/* Define this symbol if the BSD getentropy system call is available with
+   sys/random.h */
+#cmakedefine HAVE_GETENTROPY_RAND 1
+
+/* Define this symbol if the Linux getrandom function call is available */
+#cmakedefine HAVE_GETRANDOM 1
+
+/* Define this symbol if you have malloc_info */
+#cmakedefine HAVE_MALLOC_INFO 1
+
+/* Define this symbol if you have mallopt with M_ARENA_MAX */
+#cmakedefine HAVE_MALLOPT_ARENA_MAX 1
+
+/* Define to 1 if O_CLOEXEC flag is available. */
+#cmakedefine01 HAVE_O_CLOEXEC
+
+/* Define this symbol if you have posix_fallocate */
+#cmakedefine HAVE_POSIX_FALLOCATE 1
+
+/* Define this symbol if platform supports unix domain sockets */
+#cmakedefine HAVE_SOCKADDR_UN 1
+
+/* Define this symbol to build code that uses getauxval */
+#cmakedefine HAVE_STRONG_GETAUXVAL 1
+
+/* Define this symbol if the BSD sysctl() is available */
+#cmakedefine HAVE_SYSCTL 1
+
+/* Define this symbol if the BSD sysctl(KERN_ARND) is available */
+#cmakedefine HAVE_SYSCTL_ARND 1
+
+/* Define to 1 if std::system or ::wsystem is available. */
+#cmakedefine HAVE_SYSTEM 1
+
+/* Define to 1 if you have the <sys/prctl.h> header file. */
+#cmakedefine HAVE_SYS_PRCTL_H 1
+
+/* Define to 1 if you have the <sys/resources.h> header file. */
+#cmakedefine HAVE_SYS_RESOURCES_H 1
+
+/* Define to 1 if you have the <sys/vmmeter.h> header file. */
+#cmakedefine HAVE_SYS_VMMETER_H 1
+
+/* Define to 1 if you have the <vm/vm_param.h> header file. */
+#cmakedefine HAVE_VM_VM_PARAM_H 1
+
 /* Define to the address where bug reports for this package should be sent. */
 #define PACKAGE_BUGREPORT "@PACKAGE_BUGREPORT@"
 
@@ -41,4 +110,7 @@
 /* Define to the version of this package. */
 #define PACKAGE_VERSION "@PACKAGE_VERSION@"
 
+/* Define to 1 if strerror_r returns char *. */
+#cmakedefine STRERROR_R_CHAR_P 1
+
 #endif //BITCOIN_CONFIG_H
diff --git a/cmake/introspection.cmake b/cmake/introspection.cmake
new file mode 100644
index 0000000000..8d385b7ccf
--- /dev/null
+++ b/cmake/introspection.cmake
@@ -0,0 +1,160 @@
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+include(CheckCXXSourceCompiles)
+include(CheckCXXSymbolExists)
+include(CheckIncludeFileCXX)
+
+# The following HAVE_{HEADER}_H variables go to the bitcoin-config.h header.
+check_include_file_cxx(sys/prctl.h HAVE_SYS_PRCTL_H)
+check_include_file_cxx(sys/resources.h HAVE_SYS_RESOURCES_H)
+check_include_file_cxx(sys/vmmeter.h HAVE_SYS_VMMETER_H)
+check_include_file_cxx(vm/vm_param.h HAVE_VM_VM_PARAM_H)
+
+check_cxx_symbol_exists(O_CLOEXEC "fcntl.h" HAVE_O_CLOEXEC)
+check_cxx_symbol_exists(fdatasync "unistd.h" HAVE_FDATASYNC)
+check_cxx_symbol_exists(fork "unistd.h" HAVE_DECL_FORK)
+check_cxx_symbol_exists(pipe2 "unistd.h" HAVE_DECL_PIPE2)
+check_cxx_symbol_exists(setsid "unistd.h" HAVE_DECL_SETSID)
+
+check_include_file_cxx(sys/types.h HAVE_SYS_TYPES_H)
+check_include_file_cxx(ifaddrs.h HAVE_IFADDRS_H)
+if(HAVE_SYS_TYPES_H AND HAVE_IFADDRS_H)
+  include(TestAppendRequiredLibraries)
+  test_append_socket_library(core_interface)
+endif()
+
+include(TestAppendRequiredLibraries)
+test_append_atomic_library(core_interface)
+
+check_cxx_symbol_exists(std::system "cstdlib" HAVE_STD_SYSTEM)
+check_cxx_symbol_exists(::_wsystem "stdlib.h" HAVE__WSYSTEM)
+if(HAVE_STD_SYSTEM OR HAVE__WSYSTEM)
+  set(HAVE_SYSTEM 1)
+endif()
+
+check_cxx_source_compiles("
+  #include <string.h>
+
+  int main()
+  {
+    char buf[100];
+    char* p{strerror_r(0, buf, sizeof buf)};
+    (void)p;
+  }
+  " STRERROR_R_CHAR_P
+)
+
+# Check for malloc_info (for memory statistics information in getmemoryinfo).
+check_cxx_symbol_exists(malloc_info "malloc.h" HAVE_MALLOC_INFO)
+
+# Check for mallopt(M_ARENA_MAX) (to set glibc arenas).
+check_cxx_source_compiles("
+  #include <malloc.h>
+
+  int main()
+  {
+    mallopt(M_ARENA_MAX, 1);
+  }
+  " HAVE_MALLOPT_ARENA_MAX
+)
+
+# Check for posix_fallocate().
+check_cxx_source_compiles("
+  // same as in src/util/fs_helpers.cpp
+  #ifdef __linux__
+  #ifdef _POSIX_C_SOURCE
+  #undef _POSIX_C_SOURCE
+  #endif
+  #define _POSIX_C_SOURCE 200112L
+  #endif // __linux__
+  #include <fcntl.h>
+
+  int main()
+  {
+    return posix_fallocate(0, 0, 0);
+  }
+  " HAVE_POSIX_FALLOCATE
+)
+
+# Check for strong getauxval() support in the system headers.
+check_cxx_source_compiles("
+  #include <sys/auxv.h>
+
+  int main()
+  {
+    getauxval(AT_HWCAP);
+  }
+  " HAVE_STRONG_GETAUXVAL
+)
+
+# Check for UNIX sockets.
+check_cxx_source_compiles("
+  #include <sys/socket.h>
+  #include <sys/un.h>
+
+  int main()
+  {
+    struct sockaddr_un addr;
+    addr.sun_family = AF_UNIX;
+  }
+  " HAVE_SOCKADDR_UN
+)
+
+# Check for different ways of gathering OS randomness:
+# - Linux getrandom()
+check_cxx_source_compiles("
+  #include <sys/random.h>
+
+  int main()
+  {
+    getrandom(nullptr, 32, 0);
+  }
+  " HAVE_GETRANDOM
+)
+
+# - BSD getentropy()
+check_cxx_source_compiles("
+  #include <sys/random.h>
+
+  int main()
+  {
+    getentropy(nullptr, 32);
+  }
+  " HAVE_GETENTROPY_RAND
+)
+
+
+# - BSD sysctl()
+check_cxx_source_compiles("
+  #include <sys/types.h>
+  #include <sys/sysctl.h>
+
+  #ifdef __linux__
+  #error Don't use sysctl on Linux, it's deprecated even when it works
+  #endif
+
+  int main()
+  {
+    sysctl(nullptr, 2, nullptr, nullptr, nullptr, 0);
+  }
+  " HAVE_SYSCTL
+)
+
+# - BSD sysctl(KERN_ARND)
+check_cxx_source_compiles("
+  #include <sys/types.h>
+  #include <sys/sysctl.h>
+
+  #ifdef __linux__
+  #error Don't use sysctl on Linux, it's deprecated even when it works
+  #endif
+
+  int main()
+  {
+    static int name[2] = {CTL_KERN, KERN_ARND};
+    sysctl(name, 2, nullptr, nullptr, nullptr, 0);
+  }
+  " HAVE_SYSCTL_ARND
+)
diff --git a/cmake/module/CheckSourceCompilesAndLinks.cmake b/cmake/module/CheckSourceCompilesAndLinks.cmake
new file mode 100644
index 0000000000..88c897d524
--- /dev/null
+++ b/cmake/module/CheckSourceCompilesAndLinks.cmake
@@ -0,0 +1,39 @@
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+include_guard(GLOBAL)
+include(CheckCXXSourceCompiles)
+include(CMakePushCheckState)
+
+# This avoids running the linker.
+set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+macro(check_cxx_source_links source)
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE EXECUTABLE)
+  check_cxx_source_compiles("${source}" ${ARGN})
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+endmacro()
+
+macro(check_cxx_source_compiles_with_flags flags source)
+  cmake_push_check_state(RESET)
+  set(CMAKE_REQUIRED_FLAGS ${flags})
+  list(JOIN CMAKE_REQUIRED_FLAGS " " CMAKE_REQUIRED_FLAGS)
+  check_cxx_source_compiles("${source}" ${ARGN})
+  cmake_pop_check_state()
+endmacro()
+
+macro(check_cxx_source_links_with_flags flags source)
+  cmake_push_check_state(RESET)
+  set(CMAKE_REQUIRED_FLAGS ${flags})
+  list(JOIN CMAKE_REQUIRED_FLAGS " " CMAKE_REQUIRED_FLAGS)
+  check_cxx_source_links("${source}" ${ARGN})
+  cmake_pop_check_state()
+endmacro()
+
+macro(check_cxx_source_links_with_libs libs source)
+  cmake_push_check_state(RESET)
+  set(CMAKE_REQUIRED_LIBRARIES "${libs}")
+  check_cxx_source_links("${source}" ${ARGN})
+  cmake_pop_check_state()
+endmacro()
diff --git a/cmake/module/TestAppendRequiredLibraries.cmake b/cmake/module/TestAppendRequiredLibraries.cmake
new file mode 100644
index 0000000000..5352102c7a
--- /dev/null
+++ b/cmake/module/TestAppendRequiredLibraries.cmake
@@ -0,0 +1,92 @@
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+include_guard(GLOBAL)
+
+# Illumos/SmartOS requires linking with -lsocket if
+# using getifaddrs & freeifaddrs.
+# See:
+# - https://github.com/bitcoin/bitcoin/pull/21486
+# - https://smartos.org/man/3socket/getifaddrs
+function(test_append_socket_library target)
+  if (NOT TARGET ${target})
+    message(FATAL_ERROR "${CMAKE_CURRENT_FUNCTION}() called with non-existent target \"${target}\".")
+  endif()
+
+  set(check_socket_source "
+    #include <sys/types.h>
+    #include <ifaddrs.h>
+
+    int main() {
+      struct ifaddrs* ifaddr;
+      getifaddrs(&ifaddr);
+      freeifaddrs(ifaddr);
+    }
+  ")
+
+  include(CheckSourceCompilesAndLinks)
+  check_cxx_source_links("${check_socket_source}" IFADDR_LINKS_WITHOUT_LIBSOCKET)
+  if(NOT IFADDR_LINKS_WITHOUT_LIBSOCKET)
+    check_cxx_source_links_with_libs(socket "${check_socket_source}" IFADDR_NEEDS_LINK_TO_LIBSOCKET)
+    if(IFADDR_NEEDS_LINK_TO_LIBSOCKET)
+      target_link_libraries(${target} INTERFACE socket)
+    else()
+      message(FATAL_ERROR "Cannot figure out how to use getifaddrs/freeifaddrs.")
+    endif()
+  endif()
+  set(HAVE_DECL_GETIFADDRS TRUE PARENT_SCOPE)
+  set(HAVE_DECL_FREEIFADDRS TRUE PARENT_SCOPE)
+endfunction()
+
+# Clang, when building for 32-bit,
+# and linking against libstdc++, requires linking with
+# -latomic if using the C++ atomic library.
+# Can be tested with: clang++ -std=c++20 test.cpp -m32
+#
+# Sourced from http://bugs.debian.org/797228
+function(test_append_atomic_library target)
+  if (NOT TARGET ${target})
+    message(FATAL_ERROR "${CMAKE_CURRENT_FUNCTION}() called with non-existent target \"${target}\".")
+  endif()
+
+  set(check_atomic_source "
+    #include <atomic>
+    #include <cstdint>
+    #include <chrono>
+
+    using namespace std::chrono_literals;
+
+    int main() {
+      std::atomic<bool> lock{true};
+      lock.exchange(false);
+
+      std::atomic<std::chrono::seconds> t{0s};
+      t.store(2s);
+      auto t1 = t.load();
+      t.compare_exchange_strong(t1, 3s);
+
+      std::atomic<double> d{};
+      d.store(3.14);
+      auto d1 = d.load();
+
+      std::atomic<int64_t> a{};
+      int64_t v = 5;
+      int64_t r = a.fetch_add(v);
+      return static_cast<int>(r);
+    }
+  ")
+
+  include(CheckSourceCompilesAndLinks)
+  check_cxx_source_links("${check_atomic_source}" STD_ATOMIC_LINKS_WITHOUT_LIBATOMIC)
+  if(STD_ATOMIC_LINKS_WITHOUT_LIBATOMIC)
+    return()
+  endif()
+
+  check_cxx_source_links_with_libs(atomic "${check_atomic_source}" STD_ATOMIC_NEEDS_LINK_TO_LIBATOMIC)
+  if(STD_ATOMIC_NEEDS_LINK_TO_LIBATOMIC)
+    target_link_libraries(${target} INTERFACE atomic)
+  else()
+    message(FATAL_ERROR "Cannot figure out how to use std::atomic.")
+  endif()
+endfunction()