cmake: Introduce symbol versioning

This adds a cmake module, FindABIMap, which looks for abimap and
provides functions to generate a symbol version linker script.

The module can be included using find_package(ABIMap).

This also adds the option to compile with symbol versioning.  The symbol
list is obtained from the header files by filtering those marked with
the LIBSSH_API modifier.

Such symbols are used as input to generate the version script used by
the linker.  The version script is automatically updated as new symbols
marked with LIBSSH_API are added to the header files.

If any symbol is removed, the build will fail due to break in the ABI.

Symbol versioning is enabled by default if abimap has been found. It is
disabled in non-UNIX platforms. It can be disabled by passing
"-DWITH_SYMBOL_VERSIONING=OFF" option to cmake.

Pair-Programmed-With: Andreas Schneider <asn@cryptomilk.org>

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

CMakeLists.txt

@@ -81,6 +81,13 @@ if (BSD OR SOLARIS OR OSX)
     find_package(Argp)
 endif (BSD OR SOLARIS OR OSX)
 
+# Disable symbol versioning in non UNIX platforms
+if (UNIX)
+    find_package(ABIMap)
+else (UNIX)
+    set(WITH_SYMBOL_VERSIONING OFF)
+endif (UNIX)
+
 # config.h checks
 include(ConfigureChecks.cmake)
 configure_file(config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config.h)
@@ -132,6 +139,60 @@ if (UNIT_TESTING)
   add_subdirectory(tests)
 endif (UNIT_TESTING)
 
+### SOURCE PACKAGE
+if (WITH_SYMBOL_VERSIONING AND ABIMAP_FOUND)
+    # Get the current ABI version from source
+    get_filename_component(current_abi_path
+                           "${CMAKE_SOURCE_DIR}/src/ABI/current"
+                           ABSOLUTE)
+
+    # Check if the ABI version should be updated
+    file(READ ${current_abi_path} CURRENT_ABI_CONTENT)
+    string(STRIP "${CURRENT_ABI_CONTENT}" CURRENT_ABI_VERSION)
+
+    if (LIBRARY_VERSION VERSION_GREATER CURRENT_ABI_VERSION)
+        set(UPDATE_ABI TRUE)
+    endif ()
+
+    if (UPDATE_ABI)
+        message(STATUS "Library version bumped to ${LIBRARY_VERSION}: Updating ABI")
+
+        # Get the list of header files
+        get_file_list("${PROJECT_NAME}_header_list"
+                      DIRECTORIES "${CMAKE_SOURCE_DIR}/include/libssh"
+                      FILES_PATTERNS "*.h")
+
+        # Extract the symbols marked as "LIBSSH_API" from the header files
+        extract_symbols(${PROJECT_NAME}.symbols
+                        HEADERS_LIST_FILE "${PROJECT_NAME}_header_list"
+                        FILTER_PATTERN "LIBSSH_API"
+                        COPY_TO "${CMAKE_SOURCE_DIR}/src/ABI/${PROJECT_NAME}-${LIBRARY_VERSION}.symbols")
+
+        if (WITH_ABI_BREAK)
+            set(ALLOW_ABI_BREAK "BREAK_ABI")
+        endif()
+
+        # Target we can depend on in 'make dist'
+        set(_SYMBOL_TARGET "${PROJECT_NAME}.map")
+
+        # Set the path to the current map file
+        set(MAP_PATH "${CMAKE_SOURCE_DIR}/src/${_SYMBOL_TARGET}")
+
+        # Generate the symbol version map file
+        generate_map_file(${_SYMBOL_TARGET}
+                          SYMBOLS "${PROJECT_NAME}.symbols"
+                          RELEASE_NAME_VERSION ${PROJECT_NAME}_${LIBRARY_VERSION}
+                          CURRENT_MAP ${MAP_PATH}
+                          COPY_TO ${MAP_PATH}
+                          FINAL
+                          ${ALLOW_ABI_BREAK})
+
+        # Write the current version to the source
+        file(WRITE ${current_abi_path} ${LIBRARY_VERSION})
+    endif(UPDATE_ABI)
+endif (WITH_SYMBOL_VERSIONING AND ABIMAP_FOUND)
+
+add_custom_target(dist COMMAND ${CMAKE_MAKE_PROGRAM} package_source DEPENDS ${_SYMBOL_TARGET})
 
 message(STATUS "********************************************")
 message(STATUS "********** ${PROJECT_NAME} build options : **********")
@@ -158,5 +219,8 @@ else (WITH_INTERNAL_DOC)
     message(STATUS "Public API documentation generation")
 endif (WITH_INTERNAL_DOC)
 message(STATUS "Benchmarks: ${WITH_BENCHMARKS}")
+message(STATUS "Symbol versioning: ${WITH_SYMBOL_VERSIONING}")
+message(STATUS "Allow ABI break: ${WITH_ABI_BREAK}")
+message(STATUS "Release is final: ${WITH_FINAL}")
 message(STATUS "********************************************")
 

DefineOptions.cmake

@@ -16,6 +16,8 @@ option(SERVER_TESTING "Build with server tests; requires openssh and dropbear" O
 option(WITH_BENCHMARKS "Build benchmarks tools" OFF)
 option(WITH_EXAMPLES "Build examples" ON)
 option(WITH_NACL "Build with libnacl (curve25519)" ON)
+option(WITH_SYMBOL_VERSIONING "Build with symbol versioning" ON)
+option(WITH_ABI_BREAK "Allow ABI break" OFF)
 option(FUZZ_TESTING "Build with fuzzer for the server" OFF)
 if (WITH_ZLIB)
     set(WITH_LIBZ ON)
@@ -34,3 +36,7 @@ endif (UNIT_TESTING)
 if (WITH_NACL)
   set(WITH_NACL ON)
 endif (WITH_NACL)
+
+if (WITH_ABI_BREAK)
+  set(WITH_SYMBOL_VERSIONING ON)
+endif (WITH_ABI_BREAK)

cmake/Modules/ExtractSymbols.cmake

@@ -0,0 +1,88 @@
+#
+#  Copyright (c) 2018 Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
+#
+#  Redistribution and use is allowed according to the terms of the New
+#  BSD license.
+#  For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+#
+
+#.rst:
+# ExtractSymbols
+# --------------
+#
+# This is a helper script for FindABImap.cmake.
+#
+# Extract symbols from header files and output a list to a file.
+# This script is run in build time to extract symbols from the provided header
+# files. This way, symbols added or removed can be checked and used to update
+# the symbol version script.
+#
+# All symbols followed by the character ``'('`` are extracted. If a
+# ``FILTER_PATTERN`` is provided, only the lines containing the given string are
+# considered.
+#
+# Expected defined variables
+# --------------------------
+#
+# ``HEADERS_LIST_FILE``:
+#   Required, expects a file containing the list of header files to be parsed.
+#
+# ``OUTPUT_PATH``:
+#   Required, expects the output file path.
+#
+# Optionally defined variables
+# ----------------------------
+#
+# ``FILTER_PATTERN``:
+#   Expects a string. Only lines containing the given string will be considered
+#   when extracting symbols.
+#
+
+if (NOT DEFINED OUTPUT_PATH)
+    message(SEND_ERROR "OUTPUT_PATH not defined")
+endif()
+
+if (NOT DEFINED HEADERS_LIST_FILE)
+    message(SEND_ERROR "HEADERS not defined")
+endif()
+
+file(READ ${HEADERS_LIST_FILE} HEADERS_LIST)
+
+set(symbols)
+foreach(header ${HEADERS_LIST})
+
+    # Filter only lines containing the FILTER_PATTERN
+    file(STRINGS ${header} contain_filter
+      REGEX "^.*${FILTER_PATTERN}.*[(]"
+    )
+
+    # Remove function-like macros
+    foreach(line ${contain_filter})
+        if (NOT ${line} MATCHES ".*#[ ]*define")
+            list(APPEND not_macro ${line})
+        endif()
+    endforeach()
+
+    set(functions)
+
+    # Get only the function names followed by '('
+    foreach(line ${not_macro})
+        string(REGEX MATCHALL "[a-zA-Z0-9_]+[ ]*[(]" func ${line})
+        list(APPEND functions ${func})
+    endforeach()
+
+    set(extracted_symbols)
+
+    # Remove '('
+    foreach(line ${functions})
+        string(REGEX REPLACE "[(]" "" symbol ${line})
+        string(STRIP "${symbol}" symbol)
+        list(APPEND extracted_symbols ${symbol})
+    endforeach()
+
+    list(APPEND symbols ${extracted_symbols})
+endforeach()
+
+list(REMOVE_DUPLICATES symbols)
+
+file(WRITE ${OUTPUT_PATH} "${symbols}")

cmake/Modules/FindABIMap.cmake

@@ -0,0 +1,394 @@
+#
+#  Copyright (c) 2018 Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
+#
+#  Redistribution and use is allowed according to the terms of the New
+#  BSD license.
+#  For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+#
+
+#.rst:
+# FindABIMap
+# ----------
+#
+# This file provides functions to generate the symbol version script. It uses
+# the ``abimap`` tool to generate and update the linker script file. It can be
+# installed by calling::
+#
+#   $ pip install abimap
+#
+# The ``function generate_map_file`` generates a symbol version script
+# containing the provided symbols. It defines a custom command which sets
+# ``target_name`` as its ``OUTPUT``.
+#
+# The experimental function ``extract_symbols()`` is provided as a simple
+# parser to extract the symbols from C header files. It simply extracts symbols
+# followed by an opening '``(``'. It is recommended to use a filter pattern to
+# select the lines to be considered. It defines a custom command which sets
+# ``target_name`` as its output.
+#
+# The helper function ``get_files_list()`` is provided to find files given a
+# name pattern. It defines a custom command which sets ``target_name`` as its
+# output.
+#
+# Functions provided
+# ------------------
+#
+# ::
+#
+#   generate_map_file(target_name
+#                     RELEASE_NAME_VERSION release_name
+#                     SYMBOLS symbols_file
+#                     [CURRENT_MAP cur_map]
+#                     [FINAL]
+#                     [BREAK_ABI]
+#                     [COPY_TO output]
+#                    )
+#
+# ``target_name``:
+#   Required, expects the name of the file to receive the generated symbol
+#   version script. It should be added as a dependency for the library. Use the
+#   linker option ``--version-script filename`` to add the version information
+#   to the symbols when building the library.
+#
+# ``RELEASE_NAME_VERSION``:
+#   Required, expects a string containing the name and version information to be
+#   added to the symbols in the format ``lib_name_1_2_3``.
+#
+# ``SYMBOLS``:
+#   Required, expects a file containing the list of symbols to be added to the
+#   symbol version script.
+#
+# ``CURRENT_MAP``:
+#   Optional. If given, the new set of symbols will be checked against the
+#   ones contained in the ``cur_map`` file and updated properly. If an
+#   incompatible change is detected and ``BREAK_ABI`` is not defined, the build
+#   will fail.
+#
+# ``FINAL``:
+#   Optional. If given, will provide the ``--final`` option to ``abimap`` tool,
+#   which will mark the modified release in the symbol version script with a
+#   special comment, preventing later changes. This option should be set when
+#   creating a library release and the resulting map file should be stored with
+#   the source code.
+#
+# ``BREAK_ABI``:
+#   Optional. If provided, will use ``abimap`` ``--allow-abi-break`` option, which
+#   accepts incompatible changes to the set of symbols. This is necessary if any
+#   previously existing symbol were removed.
+#
+# ``COPY_TO``:
+#   Optional, expects a string containing the path to where the generated
+#   map file will be copied.
+#
+# Example:
+#
+# .. code-block:: cmake
+#
+#   find_package(ABIMap)
+#   generate_map_file("lib.map"
+#                     RELEASE_NAME_VERSION "lib_1_0_0"
+#                     SYMBOLS "symbol1;symbol2"
+#                    )
+#
+# This example would result in the symbol version script to be created in
+# ``${CMAKE_CURRENT_BINARY_DIR}/lib.map`` containing the provided symbols.
+#
+# ::
+#
+#   get_files_list(target_name
+#                   DIRECTORIES dir1 [dir2 ...]
+#                   FILES_PATTERNS exp1 [exp2 ...]
+#                   [COPY_TO output]
+#                  )
+#
+# ``target_name``:
+#   Required, expects the name of the target to be created. A file named after
+#   the string given in ``target_name`` will be created in
+#   ``${CMAKE_CURRENT_BINARY_DIR}`` to receive the list of files found.
+#
+# ``DIRECTORIES``:
+#   Required, expects a list of directories paths. Only absolute paths are
+#   supported.
+#
+# ``FILES_PATTERN``:
+#   Required, expects a list of matching expressions to find the files to be
+#   considered.
+#
+# ``COPY_TO``:
+#   Optional, expects a string containing the path to where the file containing
+#   the list of files will be copied.
+#
+# This command searches the directories provided in ``DIRECTORIES`` for files
+# matching any of the patterns provided in ``FILES_PATTERNS``. The obtained list
+# is written to the path specified by ``output``.
+#
+# Example:
+#
+# .. code-block:: cmake
+#
+#   find_package(ABIMap)
+#   get_files_list(target
+#     DIRECTORIES "/include/mylib"
+#     FILES_PATTERNS "*.h"
+#     COPY_TO "my_list.txt"
+#   )
+#
+# Consider that ``/include/mylib`` contains 3 files, ``h1.h``, ``h2.h``, and
+# ``h3.hpp``
+#
+# Will result in a file ``my_list.txt`` containing::
+#
+#   ``h1.h;h2.h``
+#
+# ::
+#
+#   extract_symbols(target_name
+#                   HEADERS_LIST_FILE headers_list
+#                   [FILTER_PATTERN pattern]
+#                   [COPY_TO output]
+#                  )
+#
+# ``target_name``:
+#   Required, expects the name of the target to be created. A file named after
+#   the string given in ``target_name`` will be created in
+#   ``${CMAKE_CURRENT_BINARY_DIR}`` to receive the list of symbols.
+#
+# ``HEADERS_LIST_FILE``:
+#   Required, expects a path to a file containing the list of header files to be
+#   parsed.
+#
+# ``FILTER_PATTERN``:
+#   Optional, expects a string. Only the lines containing the filter pattern
+#   will be considered.
+#
+# ``COPY_TO``:
+#   Optional, expects a string containing the path to where the file containing
+#   the found symbols will be copied.
+#
+# This command extracts the symbols from the files listed in
+# ``headers_list`` and write them on the ``output`` file. If ``pattern``
+# is provided, then only the lines containing the string given in ``pattern``
+# will be considered. It is recommended to provide a ``FILTER_PATTERN`` to mark
+# the lines containing exported function declaration, since this function is
+# experimental and can return wrong symbols when parsing the header files.
+#
+# Example:
+#
+# .. code-block:: cmake
+#
+#   find_package(ABIMap)
+#   extract_symbols("lib.symbols"
+#     HEADERS_LIST_FILE "headers_list"
+#     FILTER_PATTERN "API_FUNCTION"
+#   )
+#
+# Where headers_list contains::
+#
+#   header1.h;header2.h
+#
+# Where ``header1.h`` contains::
+#
+#   API_FUNCTION int exported_func1(int a, int b);
+#
+# ``header2.h`` contains::
+#
+#   API_FUNCTION int exported_func2(int a);
+#
+#   int private_func2(int b);
+#
+# Will result in a file ``lib.symbols`` in ``${CMAKE_CURRENT_BINARY_DIR}`` containing::
+#
+#   ``exported_func1;exported_func2``
+#
+
+# Search for python which is required
+find_package(PythonInterp REQUIRED)
+
+# Search for abimap tool used to generate the map files
+find_program(ABIMAP_EXECUTABLE NAMES abimap DOC "path to the abimap executable")
+mark_as_advanced(ABIMAP_EXECUTABLE)
+
+if (NOT ABIMAP_EXECUTABLE AND UNIX)
+    message(STATUS "Could not find `abimap` in PATH."
+                   " It can be found in PyPI as `abimap`"
+                   " (try `pip install abimap`)")
+else ()
+    set(ABIMAP_FOUND TRUE)
+endif ()
+
+# Define helper scripts
+set(_EXTRACT_SYMBOLS_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/ExtractSymbols.cmake)
+set(_GENERATE_MAP_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/GenerateMap.cmake)
+set(_GET_FILES_LIST_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/GetFilesList.cmake)
+
+function(get_file_list _TARGET_NAME)
+
+    set(one_value_arguments
+      COPY_TO
+    )
+
+    set(multi_value_arguments
+      DIRECTORIES
+      FILES_PATTERNS
+    )
+
+    cmake_parse_arguments(_get_files_list
+      ""
+      "${one_value_arguments}"
+      "${multi_value_arguments}"
+      ${ARGN}
+    )
+
+    # The DIRS argument is required
+    if (NOT DEFINED _get_files_list_DIRECTORIES)
+        message(FATAL_ERROR "No directories paths provided. Provide a list of"
+                            " directories paths containing header files."
+         )
+     endif()
+
+    # The FILES_PATTERNS argument is required
+    if (NOT DEFINED _get_files_list_FILES_PATTERNS)
+        message(FATAL_ERROR "No matching expressions provided. Provide a list"
+                            " of matching patterns for the header files."
+        )
+    endif()
+
+    get_filename_component(_get_files_list_OUTPUT_PATH
+      "${CMAKE_CURRENT_BINARY_DIR}/${_TARGET_NAME}"
+      ABSOLUTE
+    )
+
+    add_custom_command(
+        OUTPUT ${_TARGET_NAME}
+        COMMAND ${CMAKE_COMMAND}
+          -DOUTPUT_PATH="${_get_files_list_OUTPUT_PATH}"
+          -DDIRECTORIES="${_get_files_list_DIRECTORIES}"
+          -DFILES_PATTERNS="${_get_files_list_FILES_PATTERNS}"
+          -P ${_GET_FILES_LIST_SCRIPT}
+        COMMENT
+          "Searching for files"
+    )
+
+    if (DEFINED _get_files_list_COPY_TO)
+        # Copy the generated file back to the COPY_TO
+        add_custom_target(copy_headers_list_${TARGET_NAME} ALL
+            COMMAND
+                ${CMAKE_COMMAND} -E copy_if_different ${_TARGET_NAME} ${_get_files_list_COPY_TO}
+            DEPENDS "${_TARGET_NAME}"
+            COMMENT "Copying ${_TARGET_NAME} to ${_get_files_list_COPY_TO}"
+        )
+    endif()
+endfunction()
+
+function(extract_symbols _TARGET_NAME)
+
+    set(one_value_arguments
+      FILTER_PATTERN
+      HEADERS_LIST_FILE
+      COPY_TO
+    )
+
+    set(multi_value_arguments
+    )
+
+    cmake_parse_arguments(_extract_symbols
+      ""
+      "${one_value_arguments}"
+      "${multi_value_arguments}"
+      ${ARGN}
+    )
+
+    # The HEADERS_LIST_FILE argument is required
+    if (NOT DEFINED _extract_symbols_HEADERS_LIST_FILE)
+        message(FATAL_ERROR "No header files given. Provide a list of header"
+                            " files containing exported symbols."
+        )
+    endif()
+
+    get_filename_component(_extract_symbols_OUTPUT_PATH
+      "${CMAKE_CURRENT_BINARY_DIR}/${_TARGET_NAME}"
+      ABSOLUTE
+    )
+
+    add_custom_target(${_TARGET_NAME}
+                      COMMAND ${CMAKE_COMMAND}
+                        -DOUTPUT_PATH="${_extract_symbols_OUTPUT_PATH}"
+                        -DHEADERS_LIST_FILE="${_extract_symbols_HEADERS_LIST_FILE}"
+                        -DFILTER_PATTERN=${_extract_symbols_FILTER_PATTERN}
+                        -P ${_EXTRACT_SYMBOLS_SCRIPT}
+                      DEPENDS ${_extract_symbols_HEADERS_LIST_FILE}
+                      COMMENT "Extracting symbols from headers")
+
+    if (DEFINED _extract_symbols_COPY_TO)
+        file(READ "${CMAKE_CURRENT_BINARY_DIR}/${_TARGET_NAME}" SYMBOL_CONTENT)
+        string(REPLACE ";" "\n" SYMBOL_CONTENT_NEW "${SYMBOL_CONTENT}")
+        file(WRITE "${_extract_symbols_COPY_TO}" "${SYMBOL_CONTENT_NEW}")
+    endif()
+endfunction()
+
+function(generate_map_file _TARGET_NAME)
+
+    set(options
+        FINAL
+        BREAK_ABI
+    )
+
+    set(one_value_arguments
+        RELEASE_NAME_VERSION
+        SYMBOLS
+        CURRENT_MAP
+        COPY_TO
+    )
+
+    set(multi_value_arguments
+    )
+
+    cmake_parse_arguments(_generate_map_file
+      "${options}"
+      "${one_value_arguments}"
+      "${multi_value_arguments}"
+      ${ARGN}
+    )
+
+    if (NOT DEFINED _generate_map_file_SYMBOLS)
+        message(FATAL_ERROR "No symbols file provided."
+        )
+    endif()
+
+    if (NOT DEFINED _generate_map_file_RELEASE_NAME_VERSION)
+        message(FATAL_ERROR "Release name and version not provided."
+          " (e.g. libname_1_0_0"
+        )
+    endif()
+
+    # Set generated map file path
+    get_filename_component(_generate_map_file_OUTPUT_PATH
+      "${CMAKE_CURRENT_BINARY_DIR}/${_TARGET_NAME}"
+      ABSOLUTE
+    )
+
+    add_custom_command(
+        OUTPUT ${_TARGET_NAME}
+        COMMAND ${CMAKE_COMMAND}
+          -DABIMAP_EXECUTABLE=${ABIMAP_EXECUTABLE}
+          -DSYMBOLS="${_generate_map_file_SYMBOLS}"
+          -DCURRENT_MAP=${_generate_map_file_CURRENT_MAP}
+          -DOUTPUT_PATH="${_generate_map_file_OUTPUT_PATH}"
+          -DFINAL=${_generate_map_file_FINAL}
+          -DBREAK_ABI=${_generate_map_file_BREAK_ABI}
+          -DRELEASE_NAME_VERSION=${_generate_map_file_RELEASE_NAME_VERSION}
+          -P ${_GENERATE_MAP_SCRIPT}
+        DEPENDS ${_generate_map_file_SYMBOLS}
+        COMMENT "Generating the map ${_TARGET_NAME}"
+    )
+
+    if (DEFINED _generate_map_file_COPY_TO)
+        # Copy the generated map back to the COPY_TO
+        add_custom_target(copy_map_${_TARGET_NAME} ALL
+            COMMAND
+                ${CMAKE_COMMAND} -E copy_if_different ${_TARGET_NAME} ${_generate_map_file_COPY_TO}
+            DEPENDS "${_TARGET_NAME}"
+            COMMENT "Copying ${_TARGET_NAME} to ${_generate_map_file_COPY_TO}"
+        )
+    endif()
+endfunction()

cmake/Modules/GenerateMap.cmake

@@ -0,0 +1,118 @@
+#
+#  Copyright (c) 2018 Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
+#
+#  Redistribution and use is allowed according to the terms of the New
+#  BSD license.
+#  For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+#
+
+#.rst:
+# GenerateMap
+# -----------
+#
+# This is a helper script for FindABImap.cmake.
+#
+# Generates a symbols version script using the abimap tool.
+# This script is run in build time to use the correct command depending on the
+# existence of the file provided ``CURRENT_MAP``.
+#
+# If the file exists, the ``abimap update`` subcommand is used to update the
+# existing map. Otherwise, the ``abimap new`` subcommand is used to create a new
+# map file.
+#
+# If the file provided in ``CURRENT_MAP`` exists, it is copied to the
+# ``OUTPUT_PATH`` before updating.
+# This is required because ``abimap`` do not generate output if no symbols were
+# changed when updating an existing file.
+#
+# Expected defined variables
+# --------------------------
+#
+# ``SYMBOLS``:
+#   Required file containing the symbols to be used as input. Usually this is
+#   the ``OUTPUT`` generated by ``extract_symbols()`` function provided in
+#   FindABImap.cmake
+#
+# ``RELEASE_NAME_VERSION``:
+#   Required, expects the library name and version information to be added to
+#   the symbols in the format ``library_name_1_2_3``
+#
+# ``CURRENT_MAP``:
+#   Required, expects the path to the current map file (or the path were it
+#   should be)
+#
+# ``OUTPUT_PATH``:
+#   Required, expects the output file path.
+#
+# ``ABIMAP_EXECUTABLE``:
+#   Required, expects the path to the ``abimap`` tool.
+#
+# Optionally defined variables
+# ----------------------------
+#
+# ``FINAL``:
+#   If defined, will mark the modified set of symbols in the symbol version
+#   script as final, preventing later changes using ``abimap``.
+#
+# ``BREAK_ABI``:
+#   If defined, the build will not fail if symbols were removed.
+#   If defined and a symbol is removed, a new release is created containing
+#   all symbols from all released versions. This makes an incompatible release.
+#
+
+if (NOT DEFINED RELEASE_NAME_VERSION)
+    message(SEND_ERROR "RELEASE_NAME_VERSION not defined")
+endif()
+
+if (NOT DEFINED SYMBOLS)
+    message(SEND_ERROR "SYMBOLS not defined")
+endif()
+
+if (NOT DEFINED CURRENT_MAP)
+    message(SEND_ERROR "CURRENT_MAP not defined")
+endif()
+
+if (NOT DEFINED OUTPUT_PATH)
+    message(SEND_ERROR "OUTPUT_PATH not defined")
+endif()
+
+if (NOT ABIMAP_EXECUTABLE)
+    message(SEND_ERROR "ABIMAP_EXECUTABLE not defined")
+endif()
+
+set(ARGS_LIST)
+
+if (FINAL)
+    list(APPEND ARGS_LIST "--final")
+endif()
+
+if (EXISTS ${CURRENT_MAP})
+    if (BREAK_ABI)
+        list(APPEND ARGS_LIST "--allow-abi-break")
+    endif()
+
+    execute_process(
+      COMMAND
+        ${CMAKE_COMMAND} -E copy_if_different ${CURRENT_MAP} ${OUTPUT_PATH}
+      COMMAND
+        ${ABIMAP_EXECUTABLE} update ${ARGS_LIST}
+        -r ${RELEASE_NAME_VERSION}
+        -i ${SYMBOLS}
+        -o ${OUTPUT_PATH}
+        ${CURRENT_MAP}
+      RESULT_VARIABLE result
+    )
+else ()
+    execute_process(
+      COMMAND
+        ${ABIMAP_EXECUTABLE} new ${ARGS_LIST}
+        -r ${RELEASE_NAME_VERSION}
+        -i ${SYMBOLS}
+        -o ${OUTPUT_PATH}
+      RESULT_VARIABLE result
+    )
+endif()
+
+if (NOT "${result}" STREQUAL "0")
+    message(SEND_ERROR "Map generation failed")
+endif()

cmake/Modules/GetFilesList.cmake

@@ -0,0 +1,59 @@
+#
+#  Copyright (c) 2018 Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
+#
+#  Redistribution and use is allowed according to the terms of the New
+#  BSD license.
+#  For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+#
+
+#.rst:
+# GetFilesList
+# ------------
+#
+# This is a helper script for FindABImap.cmake.
+#
+# Search in the provided directories for files matching the provided pattern.
+# The list of files is then written to the output file.
+#
+# Expected defined variables
+# --------------------------
+#
+# ``DIRECTORIES``:
+#   Required, expects a list of directories paths.
+#
+# ``FILES_PATTERNS``:
+#   Required, expects a list of patterns to be used to search files
+#
+# ``OUTPUT_PATH``:
+#   Required, expects the output file path.
+
+if (NOT DEFINED DIRECTORIES)
+    message(SEND_ERROR "DIRECTORIES not defined")
+endif()
+
+if (NOT DEFINED FILES_PATTERNS)
+    message(SEND_ERROR "FILES_PATTERNS not defined")
+endif()
+
+if (NOT DEFINED OUTPUT_PATH)
+    message(SEND_ERROR "OUTPUT_PATH not defined")
+endif()
+
+string(REPLACE " " ";" DIRECTORIES_LIST "${DIRECTORIES}")
+string(REPLACE " " ";" FILES_PATTERNS_LIST "${FILES_PATTERNS}")
+
+# Create the list of expressions for the files
+set(glob_expressions)
+foreach(dir ${DIRECTORIES_LIST})
+    foreach(exp ${FILES_PATTERNS_LIST})
+        list(APPEND glob_expressions
+          "${dir}/${exp}"
+        )
+    endforeach()
+endforeach()
+
+# Create the list of files
+file(GLOB files ${glob_expressions})
+
+# Write to the output
+file(WRITE ${OUTPUT_PATH} "${files}")

obj/build_make.sh

@@ -63,7 +63,7 @@ function clean_build_dir() {
 
 function usage () {
 echo "Usage: `basename $0` [--prefix /install_prefix|--build [debug|final]|--clean|--verbose|--libsuffix (32|64)|--help|--clang|--cmakedir /directory|--make
-(gmake|make)|--ccompiler (gcc|cc)|--withstaticlib|--unittesting|--clientunittesting|--withserver]"
+(gmake|make)|--ccompiler(gcc|cc)|--withstaticlib|--unittesting|--clientunittesting|--withserver|--withoutsymbolversioning]"
     cleanup_and_exit
 }
 
@@ -145,6 +145,12 @@ while test -n "$1"; do
 		*-withserver)
 			OPTIONS="${OPTIONS} -DWITH_SERVER=ON"
 		;;
+		*-withoutsymbolversioning)
+			OPTIONS="${OPTIONS} -DWITH_SYMBOL_VERSIONING=OFF"
+		;;
+		*-finalrelease)
+			OPTIONS="${OPTIONS} -DWITH_FINAL=ON"
+		;;
 		----noarg)
 			echo "$ARG does not take an argument"
 			cleanup_and_exit

src/CMakeLists.txt

@@ -1,5 +1,3 @@
-project(libssh-library C)
-
 set(LIBSSH_PUBLIC_INCLUDE_DIRS
   ${libssh_SOURCE_DIR}/include
   CACHE INTERNAL "libssh public include directories"
@@ -265,10 +263,52 @@ include_directories(
   ${LIBSSH_PRIVATE_INCLUDE_DIRS}
 )
 
+# Set the path to the default map file
+set(MAP_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${PROJECT_NAME}.map")
+
+if (WITH_SYMBOL_VERSIONING AND ABIMAP_FOUND)
+    # Get the list of header files
+    get_file_list("dev_header_list"
+                  DIRECTORIES "${LIBSSH_PUBLIC_INCLUDE_DIRS}/libssh"
+                  FILES_PATTERNS "*.h")
+
+    # Extract the symbols marked as "LIBSSH_API" from the header files
+    extract_symbols("${PROJECT_NAME}_dev.symbols"
+                    HEADERS_LIST_FILE "dev_header_list"
+                    FILTER_PATTERN "LIBSSH_API")
+
+    if (WITH_ABI_BREAK)
+        set(ALLOW_ABI_BREAK "BREAK_ABI")
+    endif()
+
+    # Generate the symbol version map file
+    generate_map_file("${PROJECT_NAME}_dev.map"
+                      SYMBOLS "${PROJECT_NAME}_dev.symbols"
+                      RELEASE_NAME_VERSION ${PROJECT_NAME}_AFTER_${LIBRARY_VERSION}
+                      CURRENT_MAP ${MAP_PATH}
+                      ${ALLOW_ABI_BREAK})
+
+    set(libssh_SRCS
+      ${libssh_SRCS}
+      ${PROJECT_NAME}_dev.map
+    )
+endif (WITH_SYMBOL_VERSIONING AND ABIMAP_FOUND)
+
 add_library(${LIBSSH_SHARED_LIBRARY} SHARED ${libssh_SRCS})
 
 target_link_libraries(${LIBSSH_SHARED_LIBRARY} ${LIBSSH_LINK_LIBRARIES})
 
+if (WITH_SYMBOL_VERSIONING)
+    if (ABIMAP_FOUND)
+        # Change path to devel map file
+        set(MAP_PATH "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}_dev.map")
+    endif (ABIMAP_FOUND)
+
+    set_target_properties(${LIBSSH_SHARED_LIBRARY}
+                          PROPERTIES LINK_FLAGS
+                          "-Wl,--version-script,\"${MAP_PATH}\"")
+endif (WITH_SYMBOL_VERSIONING)
+
 set_target_properties(
   ${LIBSSH_SHARED_LIBRARY}
     PROPERTIES