[tarantool-patches] Re: [tarantool-patches] Re: [PATCH] build: fix OpenSSL linking problems on FreeBSD
Alexander Tikhonov
avtikhon at tarantool.org
Fri Oct 18 05:30:05 MSK 2019
The path seems right and LGTM from my side.
>Четверг, 17 октября 2019, 14:57 +03:00 от Igor Munkin <imun at tarantool.org>:
>
>Sasha,
>
>Thanks, the wording is great and the whole patch LGTM.
>
>As discussed offline I've created a new follow-up ticket #4575.
>
>On 17.10.19, Alexander Turenko wrote:
>> I fixed all known flaws now: see inline answers and the whole new patch
>> at end of the email.
>>
>> WBR, Alexander Turenko.
>>
>> On Tue, Sep 24, 2019 at 04:15:56PM +0300, Igor Munkin wrote:
>> > Sasha,
>> >
>> > Thanks, see no flaws except for the issue with Apple CommandLineTools
>> > compiler on OSX Mojave you're working on. Please consider a sole minor
>> > comment below.
>>
>> Fixed it by passing -isysroot=<SDK_PATH> via CPPFLAGS (PP is a
>> preprocessor) and CFLAGS.
>>
>> Added the following paragraph to the commit message:
>>
>> | When CC is passed to libcurl's configure script, the new problem opens
>> | on Mac OS. CMake chooses XCode toolchain by default (at least on a
>> | particular system where I tried it), which requires -isysroot=<SDK_PATH>
>> | option to be passed to a preprocessor and a compiler in order to find
>> | system headers. See [2] for more information.
>> |
>> | <...>
>> |
>> | [2]: https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035623
>>
>> >
>> > On 23.09.19, Alexander Turenko wrote:
>> > > FreeBSD has OpenSSL as part of the base system: libraries are located in
>> > > /usr/lib, headers are in /usr/include. However a user may install the
>> > > library into /usr/local/{lib,include} from ports / pkg. In this case
>> > > tarantool did choose /usr/local version, while libcurl will pick up a
>> > > base system library. This is fixed by passing --with-ssl option with an
>> > > argument (/usr/local or /usr if custom -DOPENSSL_ROOT_DIR=<...> is not
>> > > passed).
>> > >
>> > > Now the behaviour is the following. If -DOPENSSL_ROOT_DIR=<...> is
>> > > passed, then try to use OpenSSL from it. Otherwise find the library in
>> > > /usr/local and then in /usr. This is right as for tarantool's crypto
>> > > module as well as for libcurl submodule.
>> > >
>> > > There is a flaw here: a user is unable to choose a base system library
>> > > if a ports / pkg version of OpenSSL is installed. The reason here is
>> > > that tarantool's crypto module depends on other libraries and
>> > > -I/usr/local/include may be added to build options. I have no good
>> > > solution for that, so `cmake . -DOPENSSL_ROOT_DIR=/usr` will give a
>> > > warning on FreeBSD and `gmake` likely will fail if libraries are of
>> > > different versions (see cmake/os.cmake comments for more information).
>> > > See also a [discussion][1] in FreeBSD community about all those /usr and
>> > > /usr/local problems.
>> > >
>> > > There were two other problems that may fail tarantool build on FreeBSD:
>> > > they are fixed in this commit and described below.
>> > >
>> > > First, libcurl's configure script chooses GCC by default if it exists
>> > > (say, installed from ports / pkg). It is unexpected behaviour when
>> > > tarantool sources itself are built with clang. Now it is fixed by
>> > > passing a compiler explicitly to the libcurl's configure script: the
>> > > library will use base system clang by default or one that a user pass to
>> > > tarantool's cmake.
>> > >
>> > > Side note: GCC has /usr/local/include in its default headers search
>> > > paths; libcurl's configure script chooses GCC as a compiler and OpenSSL
>> > > from a base system by default that leads to OpenSSL header / library
>> > > mismatch. It is the primary reason of the build fail that was fixed in
>> > > 1f2338bd809585b0b38fe07fd9f80c31747374c2 ('build: FreeBSD packages
>> > > installation'). It is not much relevant anymore, because we don't try to
>> > > link with a base system OpenSSL if /usr/local one exists (if it is asked
>> > > explicitly with -DOPENSSL_ROOT_DIR=<...> we'll do, but will give a
>> > > warning). Anyway, it is important to know such details if we'll change
>> > > build scripts in a future.
>>
>> Added a note in parentheses:
>>
>> | Side note: GCC has /usr/local/include in its default headers search
>> | paths; libcurl's configure script chooses GCC as a compiler and OpenSSL
>> | from a base system by default (when CC and --with-ssl=<...> are not set)
>> | <...>
>>
>> > >
>> > > Second, backtraces are not supported on FreeBSD, but were enabled if
>> > > libunwind headers is found. This leads to an error on cmake stage,
>> > > because of unability to find a right library (this is the bug). Now we
>> > > disable backtraces on FreeBSD by default even if libunwind is found. See
>> > > #4278 for more information.
>> > >
>> > > [1]: https://wiki.freebsd.org/WarnerLosh/UsrLocal
>> > >
>> > > Follows up #4490.
>> > > ---
>> > >
>> > > https://github.com/tarantool/tarantool/issues/4490
>> > > https://github.com/tarantool/tarantool/commits/Totktonada/gh-4490-fix-freebsd-openssl-linking-problems-full-ci
>> > >
>> > > This is more request for review of wording rather then of the code: hope
>> > > I verified it carefully enough.
>> > >
>> > > cmake/BuildLibCURL.cmake | 15 +++++++--------
>> > > cmake/compiler.cmake | 4 +++-
>> > > cmake/os.cmake | 27 +++++++++++++++++++++++++++
>> > > 3 files changed, 37 insertions(+), 9 deletions(-)
>> > >
>> > > diff --git a/cmake/BuildLibCURL.cmake b/cmake/BuildLibCURL.cmake
>> > > index 866b3c49e..45f5af23e 100644
>> > > --- a/cmake/BuildLibCURL.cmake
>> > > +++ b/cmake/BuildLibCURL.cmake
>> > > @@ -14,14 +14,10 @@ macro(curl_build)
>> > > message(FATAL_ERROR "Unable to find zlib")
>> > > endif()
>> > >
>> > > - # Set curl option to find OpenSSL library.
>> > > - if ("${OPENSSL_ROOT_DIR}" STREQUAL "")
>> > > - # Linux / FreeBSD.
>> > > - set(LIBCURL_OPENSSL_OPT "--with-ssl")
>> > > - else()
>> > > - # Mac OS.
>> > > - set(LIBCURL_OPENSSL_OPT "--with-ssl=${OPENSSL_ROOT_DIR}")
>> > > - endif()
>> > > + # Use the same OpenSSL library for libcurl as is used for
>> > > + # tarantool itself.
>> > > + get_filename_component(FOUND_OPENSSL_ROOT_DIR ${OPENSSL_INCLUDE_DIR} DIRECTORY)
>> > > + set(LIBCURL_OPENSSL_OPT "--with-ssl=${FOUND_OPENSSL_ROOT_DIR}")
>> > >
>> > > include(ExternalProject)
>> > > ExternalProject_Add(
>> > > @@ -35,6 +31,8 @@ macro(curl_build)
>> > > CONFIGURE_COMMAND
>> > > cd <SOURCE_DIR> && ./buildconf &&
>> > > cd <BINARY_DIR> && <SOURCE_DIR>/configure
>> > > + CC=${CMAKE_C_COMPILER}
>> > > + CXX=${CMAKE_CXX_COMPILER}
>> >
>> > This changeset breaks build for OSX Mojave. The note is left as a
>> > reminder of known problem to be fixed in a while.
>>
>> Yep, fixed (see CPPFLAGS and CFLAGS in the new patch).
>>
>> >
>> > > --prefix <INSTALL_DIR>
>> > > --enable-static
>> > > --enable-shared
>> > > @@ -112,6 +110,7 @@ macro(curl_build)
>> > > set(CURL_LIBRARIES ${CURL_LIBRARIES} rt)
>> > > endif()
>> > >
>> > > + unset(FOUND_OPENSSL_ROOT_DIR)
>> > > unset(LIBCURL_INSTALL_DIR)
>> > > unset(LIBCURL_BINARY_DIR)
>> > > unset(LIBCURL_SOURCE_DIR)
>> > > diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
>> > > index 887485c80..c9ad2b092 100644
>> > > --- a/cmake/compiler.cmake
>> > > +++ b/cmake/compiler.cmake
>> > > @@ -128,8 +128,10 @@ else()
>> > > endif()
>> > > find_library(UNWIND_LIBRARY PATH_SUFFIXES system NAMES ${UNWIND_LIB_NAME})
>> > >
>> > > +# Disabled backtraces support on FreeBSD by default, because of
>> > > +# gh-4278.
>> > > set(ENABLE_BACKTRACE_DEFAULT OFF)
>> > > -if (UNWIND_LIBRARY AND HAVE_LIBUNWIND_H)
>> > > +if (NOT TARGET_OS_FREEBSD AND UNWIND_LIBRARY AND HAVE_LIBUNWIND_H)
>> > > set(ENABLE_BACKTRACE_DEFAULT ON)
>> > > endif()
>> > >
>> > > diff --git a/cmake/os.cmake b/cmake/os.cmake
>> > > index ea581108b..fe96ce773 100644
>> > > --- a/cmake/os.cmake
>> > > +++ b/cmake/os.cmake
>> > > @@ -22,6 +22,33 @@ elseif (${CMAKE_SYSTEM_NAME} STREQUAL "kFreeBSD")
>> > > elseif (${CMAKE_SYSTEM_NAME} STREQUAL "FreeBSD")
>> > > set(TARGET_OS_FREEBSD 1)
>> > > find_package_message(PLATFORM "Building for FreeBSD" "${CMAKE_SYSTEM_NAME}")
>> > > +
>> > > + # FreeBSD has OpenSSL library installed in /usr as part of a
>> > > + # base system. A user may install OpenSSL from ports / pkg to
>> > > + # /usr/local. It is tricky to use the library from /usr in the
>> > > + # case, because a compilation unit can also depend on
>> > > + # libraries from /usr/local. When -I/usr/local/include is
>> > > + # passed to a compiler it will find openssl/ssl.h from
>> > > + # /usr/local/include first.
>> > > + #
>> > > + # In theory we can create a directory on the build stage and
>> > > + # fill it with symlinks to choosen headers. However this way
>> > > + # does not look as usual way to pick libraries to build
>> > > + # against. I suspect that this is common problem on FreeBSD
>> > > + # and we should wait for some general resolution from FreeBSD
>> > > + # developers rather then work it around.
>> > > + #
>> > > + # Verify that /usr is not set as a directory to pick OpenSSL
>> > > + # library and header files, because it is likely that a user
>> > > + # set it to use the library from a base system, while the
>> > > + # library is also installed into /usr/local.
>> > > + get_filename_component(REAL_OPENSSL_ROOT_DIR "${OPENSSL_ROOT_DIR}"
>> > > + REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
>> > > + if ("${REAL_OPENSSL_ROOT_DIR}" STREQUAL "/usr")
>> >
>> > It would be much clearer if you dropped a few words for the warning
>> > level usage instead of fatal one here (I guess I saw the rationale
>> > within a commit message).
>>
>> Added the following paragraph:
>>
>> | It is possible however that a user is aware of the problem,
>> | but want to use -DOPENSSL_ROOT_DIR=<...> CMake option to
>> | choose OpenSSL from /usr anyway. We should not fail the
>> | build and block this ability. Say, a user may know that
>> | there are no OpenSSL libraries in /usr/local, but finds it
>> | convenient to set the CMake option explicitly due to some
>> | external reason.
>>
>> >
>> > > + message(WARNING "Using OPENSSL_ROOT_DIR on FreeBSD to choose base "
>> > > + "system libraries is not supported")
>> > > + endif()
>> > > + unset(REAL_OPENSSL_ROOT_DIR)
>> > > elseif (${CMAKE_SYSTEM_NAME} STREQUAL "NetBSD")
>> > > set(TARGET_OS_NETBSD 1)
>> > > find_package_message(PLATFORM "Building for NetBSD" "${CMAKE_SYSTEM_NAME}")
>> > > --
>> > > 2.22.0
>> > >
>> >
>> > --
>> > Best regards,
>> > IM
>>
>> ----
>>
>> build: fix OpenSSL linking problems on FreeBSD
>>
>> FreeBSD has OpenSSL as part of the base system: libraries are located in
>> /usr/lib, headers are in /usr/include. However a user may install the
>> library into /usr/local/{lib,include} from ports / pkg. In this case
>> tarantool did choose /usr/local version, while libcurl will pick up a
>> base system library. This is fixed by passing --with-ssl option with an
>> argument (/usr/local or /usr if custom -DOPENSSL_ROOT_DIR=<...> is not
>> passed).
>>
>> Now the behaviour is the following. If -DOPENSSL_ROOT_DIR=<...> is
>> passed, then try to use OpenSSL from it. Otherwise find the library in
>> /usr/local and then in /usr. This is right as for tarantool's crypto
>> module as well as for libcurl submodule.
>>
>> There is a flaw here: a user is unable to choose a base system library
>> if a ports / pkg version of OpenSSL is installed. The reason here is
>> that tarantool's crypto module depends on other libraries and
>> -I/usr/local/include may be added to build options. I have no good
>> solution for that, so `cmake . -DOPENSSL_ROOT_DIR=/usr` will give a
>> warning on FreeBSD and `gmake` likely will fail if libraries are of
>> different versions (see cmake/os.cmake comments for more information).
>> See also a [discussion][1] in FreeBSD community about all those /usr and
>> /usr/local problems.
>>
>> There were two other problems that may fail tarantool build on FreeBSD:
>> they are fixed in this commit and described below.
>>
>> First, libcurl's configure script chooses GCC by default if it exists
>> (say, installed from ports / pkg). It is unexpected behaviour when
>> tarantool sources itself are built with clang. Now it is fixed by
>> passing a compiler explicitly to the libcurl's configure script: the
>> library will use base system clang by default or one that a user pass to
>> tarantool's cmake.
>>
>> Side note: GCC has /usr/local/include in its default headers search
>> paths; libcurl's configure script chooses GCC as a compiler and OpenSSL
>> from a base system by default (when CC and --with-ssl=<...> are not set)
>> that leads to OpenSSL header / library mismatch. It is the primary
>> reason of the build fail that was fixed in
>> 1f2338bd809585b0b38fe07fd9f80c31747374c2 ('build: FreeBSD packages
>> installation'). It is not much relevant anymore, because we don't try to
>> link with a base system OpenSSL if /usr/local one exists (however if it
>> is asked explicitly with -DOPENSSL_ROOT_DIR=<...> we'll do, but will
>> give a warning). Anyway, it is important to know such details if we'll
>> change build scripts in a future.
>>
>> Second, backtraces are not supported on FreeBSD, but were enabled if
>> libunwind headers is found. This leads to an error on cmake stage,
>> because of inability to find a right library (this is a bug). Now we
>> disable backtraces on FreeBSD by default even if libunwind is found. See
>> #4278 for more information.
>>
>> When CC is passed to libcurl's configure script, the new problem opens
>> on Mac OS. CMake chooses XCode toolchain by default (at least on a
>> particular system where I tried it), which requires -isysroot=<SDK_PATH>
>> option to be passed to a preprocessor and a compiler in order to find
>> system headers. See [2] for more information.
>>
>> [1]: https://wiki.freebsd.org/WarnerLosh/UsrLocal
>> [2]: https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035623
>>
>> Follows up #4490.
>> ---
>> cmake/BuildLibCURL.cmake | 25 ++++++++++++++++++-------
>> cmake/compiler.cmake | 4 +++-
>> cmake/os.cmake | 35 +++++++++++++++++++++++++++++++++++
>> 3 files changed, 56 insertions(+), 8 deletions(-)
>>
>> diff --git a/cmake/BuildLibCURL.cmake b/cmake/BuildLibCURL.cmake
>> index 866b3c49e..0dc7676d6 100644
>> --- a/cmake/BuildLibCURL.cmake
>> +++ b/cmake/BuildLibCURL.cmake
>> @@ -14,13 +14,18 @@ macro(curl_build)
>> message(FATAL_ERROR "Unable to find zlib")
>> endif()
>>
>> - # Set curl option to find OpenSSL library.
>> - if ("${OPENSSL_ROOT_DIR}" STREQUAL "")
>> - # Linux / FreeBSD.
>> - set(LIBCURL_OPENSSL_OPT "--with-ssl")
>> - else()
>> - # Mac OS.
>> - set(LIBCURL_OPENSSL_OPT "--with-ssl=${OPENSSL_ROOT_DIR}")
>> + # Use the same OpenSSL library for libcurl as is used for
>> + # tarantool itself.
>> + get_filename_component(FOUND_OPENSSL_ROOT_DIR ${OPENSSL_INCLUDE_DIR} DIRECTORY)
>> + set(LIBCURL_OPENSSL_OPT "--with-ssl=${FOUND_OPENSSL_ROOT_DIR}")
>> +
>> + # Pass -isysroot=<SDK_PATH> option on Mac OS to a preprocessor
>> + # and a C compiler to find header files installed with an SDK.
>> + set(LIBCURL_CPPFLAGS "")
>> + set(LIBCURL_CFLAGS "")
>> + if (TARGET_OS_DARWIN AND NOT "${CMAKE_OSX_SYSROOT}" STREQUAL "")
>> + set(LIBCURL_CPPFLAGS "${LIBCURL_CPPFLAGS} ${CMAKE_C_SYSROOT_FLAG} ${CMAKE_OSX_SYSROOT}")
>> + set(LIBCURL_CFLAGS "${LIBCURL_CFLAGS} ${CMAKE_C_SYSROOT_FLAG} ${CMAKE_OSX_SYSROOT}")
>> endif()
>>
>> include(ExternalProject)
>> @@ -35,6 +40,9 @@ macro(curl_build)
>> CONFIGURE_COMMAND
>> cd <SOURCE_DIR> && ./buildconf &&
>> cd <BINARY_DIR> && <SOURCE_DIR>/configure
>> + CC=${CMAKE_C_COMPILER}
>> + CPPFLAGS=${LIBCURL_CPPFLAGS}
>> + CFLAGS=${LIBCURL_CFLAGS}
>> --prefix <INSTALL_DIR>
>> --enable-static
>> --enable-shared
>> @@ -112,6 +120,9 @@ macro(curl_build)
>> set(CURL_LIBRARIES ${CURL_LIBRARIES} rt)
>> endif()
>>
>> + unset(LIBCURL_CPPFLAGS)
>> + unset(LIBCURL_CFLAGS)
>> + unset(FOUND_OPENSSL_ROOT_DIR)
>> unset(LIBCURL_INSTALL_DIR)
>> unset(LIBCURL_BINARY_DIR)
>> unset(LIBCURL_SOURCE_DIR)
>> diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
>> index 887485c80..c9ad2b092 100644
>> --- a/cmake/compiler.cmake
>> +++ b/cmake/compiler.cmake
>> @@ -128,8 +128,10 @@ else()
>> endif()
>> find_library(UNWIND_LIBRARY PATH_SUFFIXES system NAMES ${UNWIND_LIB_NAME})
>>
>> +# Disabled backtraces support on FreeBSD by default, because of
>> +# gh-4278.
>> set(ENABLE_BACKTRACE_DEFAULT OFF)
>> -if (UNWIND_LIBRARY AND HAVE_LIBUNWIND_H)
>> +if (NOT TARGET_OS_FREEBSD AND UNWIND_LIBRARY AND HAVE_LIBUNWIND_H)
>> set(ENABLE_BACKTRACE_DEFAULT ON)
>> endif()
>>
>> diff --git a/cmake/os.cmake b/cmake/os.cmake
>> index ea581108b..0ed554b9b 100644
>> --- a/cmake/os.cmake
>> +++ b/cmake/os.cmake
>> @@ -22,6 +22,41 @@ elseif (${CMAKE_SYSTEM_NAME} STREQUAL "kFreeBSD")
>> elseif (${CMAKE_SYSTEM_NAME} STREQUAL "FreeBSD")
>> set(TARGET_OS_FREEBSD 1)
>> find_package_message(PLATFORM "Building for FreeBSD" "${CMAKE_SYSTEM_NAME}")
>> +
>> + # FreeBSD has OpenSSL library installed in /usr as part of a
>> + # base system. A user may install OpenSSL from ports / pkg to
>> + # /usr/local. It is tricky to use the library from /usr in the
>> + # case, because a compilation unit can also depend on
>> + # libraries from /usr/local. When -I/usr/local/include is
>> + # passed to a compiler it will find openssl/ssl.h from
>> + # /usr/local/include first.
>> + #
>> + # In theory we can create a directory on the build stage and
>> + # fill it with symlinks to choosen headers. However this way
>> + # does not look as usual way to pick libraries to build
>> + # against. I suspect that this is common problem on FreeBSD
>> + # and we should wait for some general resolution from FreeBSD
>> + # developers rather then work it around.
>> + #
>> + # Verify that /usr is not set as a directory to pick OpenSSL
>> + # library and header files, because it is likely that a user
>> + # set it to use the library from a base system, while the
>> + # library is also installed into /usr/local.
>> + #
>> + # It is possible however that a user is aware of the problem,
>> + # but want to use -DOPENSSL_ROOT_DIR=<...> CMake option to
>> + # choose OpenSSL from /usr anyway. We should not fail the
>> + # build and block this ability. Say, a user may know that
>> + # there are no OpenSSL libraries in /usr/local, but finds it
>> + # convenient to set the CMake option explicitly due to some
>> + # external reason.
>> + get_filename_component(REAL_OPENSSL_ROOT_DIR "${OPENSSL_ROOT_DIR}"
>> + REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
>> + if ("${REAL_OPENSSL_ROOT_DIR}" STREQUAL "/usr")
>> + message(WARNING "Using OPENSSL_ROOT_DIR on FreeBSD to choose base "
>> + "system libraries is not supported")
>> + endif()
>> + unset(REAL_OPENSSL_ROOT_DIR)
>> elseif (${CMAKE_SYSTEM_NAME} STREQUAL "NetBSD")
>> set(TARGET_OS_NETBSD 1)
>> find_package_message(PLATFORM "Building for NetBSD" "${CMAKE_SYSTEM_NAME}")
>
>--
>Best regards,
>IM
>
--
Alexander Tikhonov
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