linux_dll.cpp

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

/* ***** BEGIN LICENSE BLOCK ***** 
 * Version: RCSL 1.0/RPSL 1.0 
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 * The contents of this file, and the files included with this file, are 
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 * Version 1.0 (the "RPSL") available at 
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 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
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 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the portions 
 * it created. 
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 * This file, and the files included with this file, is distributed and made 
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 * ***** END LICENSE BLOCK ***** */ 

#include "dllacces.h"

#include <dlfcn.h>
#include <signal.h>
#include <stdio.h>

#include "platform/unix/unix_dll_common.h"

class LinuxDLLAccess : public DLLAccessImp
{
public:
    LinuxDLLAccess();
    virtual ~LinuxDLLAccess();
    virtual int Open(const char* dllName);
    virtual int Close() ;
    virtual void* GetSymbol(const char* symbolName);
    virtual const char* GetErrorStr() const;
    virtual char* CreateVersionStr(const char* dllName) const;
    virtual void CreateName(const char* short_name, const char* long_name, 
		      char* out_buf, UINT32& out_buf_len, 
		      UINT32 nMajor, UINT32 nMinor)
		      {
		          UnixCreateName(short_name, long_name, out_buf, out_buf_len,
		          nMajor, nMinor);
		      }

private:
    void* m_handle;
};

LinuxDLLAccess::LinuxDLLAccess() : 
    m_handle(0)
{}

LinuxDLLAccess::~LinuxDLLAccess()
{
    if (m_handle)
    {
        Close();
    }
}

int LinuxDLLAccess::Open(const char* dllName)
{
    int ret = DLLAccess::NO_LOAD;

    if (m_handle)
    {
        Close();
    }
    
    sigset_t newset, oldset;
    // block all signals, avoiding thread switch
    sigfillset(&newset);
    sigprocmask(SIG_SETMASK, &newset, &oldset);

    m_handle = dlopen(dllName, RTLD_LAZY);

    sigprocmask(SIG_SETMASK, &oldset, &newset);

    if (m_handle)
    {
        ret = DLLAccess::DLL_OK;
    }

    HandleHXStopOnLoad(dllName);

    return ret;
}

int LinuxDLLAccess::Close()
{
    int ret = DLLAccess::NO_LOAD;

    if(m_handle)
    {
        //GCC 2.95 does not clean up any function scope statics until
        //the atexit handler is called. This raises the problem that
        //if you have such a static defined in a DLL, and the DLL is
        //unloaded before the end of the program, you will get a seg
        //fault when the atexit handler fires as it is trying to clean
        //up memory that is no longer around. GCC 3.2 does not have
        //this problem. So, for any GCC<3.2 we will not do a
        //dlclose(). Be aware that this will make your runtime memory
        //requirment higher as all DLLs can be queried and freed at
        //startup of different apps.
#if defined(__GNUC__)
#if (__GNUC__>3 || (__GNUC__==3 && __GNUC_MINOR__>=2))
        if (!dlclose(m_handle))
        {
            ret = DLLAccess::DLL_OK;
        }
# else // GCC versin < 3
        ret = DLLAccess::DLL_OK;
# endif
#else // Not using gnu C compiler...
        if (!dlclose(m_handle))
        {
            ret = DLLAccess::DLL_OK;
        }
#endif        
        m_handle = 0;
    }

    return ret;
}

void* LinuxDLLAccess::GetSymbol(const char* symbolName)
{
    return dlsym(m_handle, symbolName);
}

const char* LinuxDLLAccess::GetErrorStr() const
{
    return dlerror();
}

char* LinuxDLLAccess::CreateVersionStr(const char* dllName) const
{
    return UnixFindDLLVersion(dllName);
}

DLLAccessImp* DLLAccess::CreatePlatformDLLImp()
{
    return new LinuxDLLAccess();
}