cmake: support OpenSSL 3 with older CMake

cmake/Modules/FindOpenSSL.cmake

@@ -0,0 +1,117 @@
+#
+# $Id$
+#
+# Created 2026/05/22
+#
+# Copyright 2026 Quantcast Corporation. All rights reserved.
+#
+# This file is part of Quantcast File System.
+#
+# Licensed under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License.
+
+# Find OpenSSL headers and libraries.
+#
+# This project still supports old CMake releases. CMake 3.5 cannot parse the
+# OpenSSL 3 version macros in opensslv.h, which can make find_package(OpenSSL)
+# fail even when OPENSSL_ROOT_DIR points to a valid OpenSSL 3 installation.
+#
+# Result variables:
+#   OPENSSL_FOUND
+#   OPENSSL_INCLUDE_DIR
+#   OPENSSL_INCLUDE_DIRS
+#   OPENSSL_SSL_LIBRARY
+#   OPENSSL_CRYPTO_LIBRARY
+#   OPENSSL_LIBRARIES
+#   OPENSSL_VERSION
+
+if(OPENSSL_ROOT_DIR)
+    find_path(OPENSSL_INCLUDE_DIR openssl/ssl.h
+        PATHS "${OPENSSL_ROOT_DIR}"
+        PATH_SUFFIXES include
+        NO_DEFAULT_PATH
+    )
+    find_library(OPENSSL_SSL_LIBRARY NAMES ssl ssleay32 ssleay32MD
+        PATHS "${OPENSSL_ROOT_DIR}"
+        PATH_SUFFIXES lib64 lib
+        NO_DEFAULT_PATH
+    )
+    find_library(OPENSSL_CRYPTO_LIBRARY NAMES crypto libeay32 libeay32MD
+        PATHS "${OPENSSL_ROOT_DIR}"
+        PATH_SUFFIXES lib64 lib
+        NO_DEFAULT_PATH
+    )
+endif()
+
+find_path(OPENSSL_INCLUDE_DIR openssl/ssl.h
+    PATH_SUFFIXES include
+)
+find_library(OPENSSL_SSL_LIBRARY NAMES ssl ssleay32 ssleay32MD
+    PATH_SUFFIXES lib64 lib
+)
+find_library(OPENSSL_CRYPTO_LIBRARY NAMES crypto libeay32 libeay32MD
+    PATH_SUFFIXES lib64 lib
+)
+
+set(OPENSSL_LIBRARIES ${OPENSSL_SSL_LIBRARY} ${OPENSSL_CRYPTO_LIBRARY})
+set(OPENSSL_INCLUDE_DIRS ${OPENSSL_INCLUDE_DIR})
+
+if(OPENSSL_INCLUDE_DIR AND EXISTS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h")
+    file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h"
+        _OPENSSL_VERSION_MAJOR_STR
+        REGEX "^#[\t ]*define[\t ]+OPENSSL_VERSION_MAJOR[\t ]+[0-9]+")
+    if(_OPENSSL_VERSION_MAJOR_STR)
+        file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h"
+            _OPENSSL_VERSION_MINOR_STR
+            REGEX "^#[\t ]*define[\t ]+OPENSSL_VERSION_MINOR[\t ]+[0-9]+")
+        file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h"
+            _OPENSSL_VERSION_PATCH_STR
+            REGEX "^#[\t ]*define[\t ]+OPENSSL_VERSION_PATCH[\t ]+[0-9]+")
+        string(REGEX REPLACE "^.*OPENSSL_VERSION_MAJOR[\t ]+([0-9]+).*$"
+            "\\1" _OPENSSL_VERSION_MAJOR "${_OPENSSL_VERSION_MAJOR_STR}")
+        string(REGEX REPLACE "^.*OPENSSL_VERSION_MINOR[\t ]+([0-9]+).*$"
+            "\\1" _OPENSSL_VERSION_MINOR "${_OPENSSL_VERSION_MINOR_STR}")
+        string(REGEX REPLACE "^.*OPENSSL_VERSION_PATCH[\t ]+([0-9]+).*$"
+            "\\1" _OPENSSL_VERSION_PATCH "${_OPENSSL_VERSION_PATCH_STR}")
+        set(OPENSSL_VERSION
+            "${_OPENSSL_VERSION_MAJOR}.${_OPENSSL_VERSION_MINOR}.${_OPENSSL_VERSION_PATCH}")
+    else()
+        file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h"
+            _OPENSSL_VERSION_NUMBER_STR
+            REGEX "^#[\t ]*define[\t ]+OPENSSL_VERSION_NUMBER[\t ]+0x[0-9a-fA-F]+.*")
+        if(_OPENSSL_VERSION_NUMBER_STR)
+            string(REGEX REPLACE
+                "^.*OPENSSL_VERSION_NUMBER[\t ]+0x([0-9a-fA-F])([0-9a-fA-F][0-9a-fA-F])([0-9a-fA-F][0-9a-fA-F]).*$"
+                "\\1;0x\\2;0x\\3" _OPENSSL_VERSION_LIST
+                "${_OPENSSL_VERSION_NUMBER_STR}")
+            list(GET _OPENSSL_VERSION_LIST 0 _OPENSSL_VERSION_MAJOR)
+            list(GET _OPENSSL_VERSION_LIST 1 _OPENSSL_VERSION_MINOR_HEX)
+            list(GET _OPENSSL_VERSION_LIST 2 _OPENSSL_VERSION_FIX_HEX)
+            math(EXPR _OPENSSL_VERSION_MINOR "${_OPENSSL_VERSION_MINOR_HEX}")
+            math(EXPR _OPENSSL_VERSION_FIX "${_OPENSSL_VERSION_FIX_HEX}")
+            set(OPENSSL_VERSION
+                "${_OPENSSL_VERSION_MAJOR}.${_OPENSSL_VERSION_MINOR}.${_OPENSSL_VERSION_FIX}")
+        endif()
+    endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(OpenSSL
+    REQUIRED_VARS OPENSSL_SSL_LIBRARY OPENSSL_CRYPTO_LIBRARY OPENSSL_INCLUDE_DIR
+    VERSION_VAR OPENSSL_VERSION
+)
+
+mark_as_advanced(
+    OPENSSL_INCLUDE_DIR
+    OPENSSL_SSL_LIBRARY
+    OPENSSL_CRYPTO_LIBRARY
+)