载入OpenSSL的动态库——学会使用tryToLoadOpenSslWin32Library和QPair

• Libraries name of openssl?

The "library" portion of OpenSSL consists of two libraries.

On posix system they are named:

• libssl
• libcrypto

while on Windows(32bit) they are named completely different:

• libeay32
• ssleay32

qsslocket_openssl_symbols.cpp

static QPair<QSystemLibrary*, QSystemLibrary*> loadOpenSslWin32()
{
    QPair<QSystemLibrary*,QSystemLibrary*> pair;
    pair.first = 0;
    pair.second = 0;

    // When OpenSSL is built using MSVC then the libraries are named 'ssleay32.dll' and 'libeay32'dll'.
    // When OpenSSL is built using GCC then different library names are used (depending on the OpenSSL version)
    // The oldest version of a GCC-based OpenSSL which can be detected by the code below is 0.9.8g (released in 2007)
    if (!tryToLoadOpenSslWin32Library(QLatin1String("ssleay32"), QLatin1String("libeay32"), pair)) {
        if (!tryToLoadOpenSslWin32Library(QLatin1String("libssl-10"), QLatin1String("libcrypto-10"), pair)) {
            if (!tryToLoadOpenSslWin32Library(QLatin1String("libssl-8"), QLatin1String("libcrypto-8"), pair)) {
                tryToLoadOpenSslWin32Library(QLatin1String("libssl-7"), QLatin1String("libcrypto-7"), pair);
            }
        }
    }

    return pair;
}

ssl.pri

    # Add optional SSL libs
    # Static linking of OpenSSL with msvc:
    #   - Binaries http://slproweb.com/products/Win32OpenSSL.html
    #   - also needs -lUser32 -lAdvapi32 -lGdi32 -lCrypt32
    #   - libs in <OPENSSL_DIR>libVCstatic
    #   - configure: -openssl -openssl-linked -I <OPENSSL_DIR>include -L <OPENSSL_DIR>libVCstatic OPENSSL_LIBS="-lUser32 -lAdvapi32 -lGdi32" OPENSSL_LIBS_DEBUG="-lssleay32MDd -llibeay32MDd" OPENSSL_LIBS_RELEASE="-lssleay32MD -llibeay32MD"

configure option

    -no-openssl ........ Do not compile support for OpenSSL.
 +  -openssl ........... Enable run-time OpenSSL support.
    -openssl-linked .... Enabled linked OpenSSL support.

Reference

• http://www.ski-epic.com/2007_notes_on_openssl/index.html
• http://sophie.zarb.org/distrib/Fedora/18/i386/by-pkgid/75c6e42b0cde6481d0fb179df846c7c1/files/8
• http://blog.debao.me/2013/12/openssl-and-qt/