gecko-dev/xpcom/components/xcDll.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is 
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 *
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 *
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/* nsDll
 *
 * Abstraction of a Dll. Stores modifiedTime and size for easy detection of
 * change in dll.
 *
 * dp Suresh <dp@netscape.com>
 */

#include "xcDll.h"
#include "nsDebug.h"
#include "nsIComponentManager.h"
#include "nsIComponentLoaderManager.h"
#include "nsIModule.h"
#include "nsILocalFile.h"
#include "nsDirectoryServiceDefs.h"
#include "nsDirectoryServiceUtils.h"
#include "nsCOMPtr.h"
#include "nsCRT.h"
#include "nsString.h"
#include "nsITimelineService.h"
#ifdef DEBUG
#if defined(VMS)
#include <lib$routines.h>
#include <ssdef.h>
#elif defined(XP_MACOSX)
#include <signal.h>
#endif
#endif /* defined(DEBUG) */

#include "nsTraceRefcntImpl.h"

#define UNLOAD_DEPENDENT_LIBS
#ifdef HPUX
#undef UNLOAD_DEPENDENT_LIBS
#endif

#include "nsNativeComponentLoader.h"

nsDll::nsDll(nsIFile *dllSpec, nsNativeComponentLoader *loader)
    : m_dllSpec(do_QueryInterface(dllSpec)),
      m_instance(NULL), 
      m_moduleObject(NULL),
      m_loader(loader),
      m_markForUnload(PR_FALSE)
{
    NS_ASSERTION(loader, "Null loader when creating a nsDLL");
}

nsDll::~nsDll(void)
{
    //#if DEBUG_dougt
    // The dll gets deleted when the dllStore is destroyed. This happens on
    // app shutdown. At that point, unloading dlls can cause crashes if we have
    // - dll dependencies
    // - callbacks
    // - static dtors
    // Hence turn it back on after all the above have been removed.
    //Unload();
    //#endif
}

void
nsDll::GetDisplayPath(nsACString& aLeafName)
{
    m_dllSpec->GetNativeLeafName(aLeafName);
    
    if (aLeafName.IsEmpty())
        aLeafName.Assign(NS_LITERAL_CSTRING("unknown!"));
}

PRBool
nsDll::HasChanged()
{
    nsCOMPtr<nsIComponentLoaderManager> manager = do_QueryInterface(m_loader->mCompMgr);
    if (!manager)
        return PR_TRUE;

    // If mod date has changed, then dll has changed
    PRInt64 currentDate;
    nsresult rv = m_dllSpec->GetLastModifiedTime(&currentDate);
    if (NS_FAILED(rv))
        return PR_TRUE;
    PRBool changed = PR_TRUE;
    manager->HasFileChanged(m_dllSpec, nsnull, currentDate, &changed); 
    return changed;
}

PRBool nsDll::Load(void)
{
	if (m_instance != NULL)
	{
		// Already loaded
		return (PR_TRUE);
	}

    if (m_dllSpec)
    {
#ifdef NS_BUILD_REFCNT_LOGGING
        nsTraceRefcntImpl::SetActivityIsLegal(PR_FALSE);
#endif
        
    // Load any library dependencies
    //   The Component Loader Manager may hold onto some extra data
    //   set by either the native component loader or the native 
    //   component.  We assume that this data is a space delimited
    //   listing of dependent libraries which are required to be
    //   loaded prior to us loading the given component.  Once, the
    //   component is loaded into memory, we can release our hold 
    //   on the dependent libraries with the assumption that the 
    //   component library holds a reference via the OS so loader.

#if defined(XP_UNIX)
    nsCOMPtr<nsIComponentLoaderManager> manager = do_QueryInterface(m_loader->mCompMgr);
    if (!manager)
        return PR_TRUE;

    nsXPIDLCString extraData;
    manager->GetOptionalData(m_dllSpec, nsnull, getter_Copies(extraData));
    
#ifdef UNLOAD_DEPENDENT_LIBS
    nsVoidArray dependentLibArray;
#endif

    // if there was any extra data, treat it as a listing of dependent libs
    if (extraData != nsnull) 
    {
        // all dependent libraries are suppose to be in the "gre" directory.
        // note that the gre directory is the same as the "bin" directory, 
        // when there isn't a real "gre" found.

        nsXPIDLCString path;
        nsCOMPtr<nsIFile> file;
        NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(file));
        
        if (!file)
            return NS_ERROR_FAILURE;

        // we are talking about a file in the GRE dir.  Lets append something
        // stupid right now, so that later we can just set the leaf name.
        file->AppendNative(NS_LITERAL_CSTRING("dummy"));

        char *buffer = strdup(extraData); 
        if (!buffer)
            return NS_ERROR_OUT_OF_MEMORY;

        char* newStr;
        char *token = nsCRT::strtok(buffer, " ", &newStr);
        while (token!=nsnull)
        {
            nsCStringKey key(token);
            if (m_loader->mLoadedDependentLibs.Get(&key)) {
                token = nsCRT::strtok(newStr, " ", &newStr);
                continue;
            }

            m_loader->mLoadedDependentLibs.Put(&key, (void*)1);

            nsXPIDLCString libpath;
            file->SetNativeLeafName(nsDependentCString(token));
            file->GetNativePath(path);
            if (!path)
                return NS_ERROR_FAILURE;

            // Load this dependent library with the global flag and stash 
            // the result for later so that we can unload it.
            PRLibSpec libSpec;
            libSpec.type = PR_LibSpec_Pathname;

            // if the depend library path starts with a / we are 
            // going to assume that it is a full path and should
            // be loaded without prepending the gre diretory 
            // location.  We could have short circuited the 
            // SetNativeLeafName above, but this is clearer and
            // the common case is a relative path.

            if (token[0] == '/')
                libSpec.value.pathname = token;
            else
                libSpec.value.pathname = path;
            
            PRLibrary* lib = PR_LoadLibraryWithFlags(libSpec, PR_LD_LAZY|PR_LD_GLOBAL);
            // if we couldn't load the dependent library.  We did the best we
            // can.  Now just let us fail later if this really was a required
            // dependency.
#ifdef UNLOAD_DEPENDENT_LIBS
            if (lib) 
                dependentLibArray.AppendElement((void*)lib);
#endif
                
            token = nsCRT::strtok(newStr, " ", &newStr);
        }
        free(buffer);
    }
#endif

    // load the component
    nsCOMPtr<nsILocalFile> lf(do_QueryInterface(m_dllSpec));
    NS_ASSERTION(lf, "nsIFile here must implement a nsILocalFile"); 
    lf->Load(&m_instance);

#if defined(XP_UNIX)
    // Unload any of library dependencies we loaded earlier. The assumption  
    // here is that the component will have a "internal" reference count to
    // the dependency library we just loaded.  
    // XXX should we unload later - or even at all?

#ifdef UNLOAD_DEPENDENT_LIBS
    if (extraData != nsnull)
    {
        PRInt32 arrayCount = dependentLibArray.Count();
        for (PRInt32 index = 0; index < arrayCount; index++)
            PR_UnloadLibrary((PRLibrary*)dependentLibArray.ElementAt(index));
    }
#endif
#endif

#ifdef NS_BUILD_REFCNT_LOGGING
        nsTraceRefcntImpl::SetActivityIsLegal(PR_TRUE);
        if (m_instance) {
            // Inform refcnt tracer of new library so that calls through the
            // new library can be traced.
            nsXPIDLCString displayPath;
            GetDisplayPath(displayPath);
            nsTraceRefcntImpl::LoadLibrarySymbols(displayPath.get(), m_instance);
        }
#endif
    }

#ifdef SHOULD_IMPLEMENT_BREAKAFTERLOAD
    // Debugging help for components. Component dlls need to have their
    // symbols loaded before we can put a breakpoint in the debugger.
    // This will help figureing out the point when the dll was loaded.
    nsXPIDLCString displayPath;
    GetDisplayPath(displayPath);
    BreakAfterLoad(displayPath.get());
#endif

    return ((m_instance == NULL) ? PR_FALSE : PR_TRUE);
}

PRBool nsDll::Unload(void)
{
	if (m_instance == NULL)
		return (PR_FALSE);

    // Shutdown the dll
    Shutdown();

#ifdef NS_BUILD_REFCNT_LOGGING
    nsTraceRefcntImpl::SetActivityIsLegal(PR_FALSE);
#endif
	PRStatus ret = PR_UnloadLibrary(m_instance);
#ifdef NS_BUILD_REFCNT_LOGGING
    nsTraceRefcntImpl::SetActivityIsLegal(PR_TRUE);
#endif

	if (ret == PR_SUCCESS)
	{
		m_instance = NULL;
		return (PR_TRUE);
	}
	else
		return (PR_FALSE);
}

void * nsDll::FindSymbol(const char *symbol)
{
	if (symbol == NULL)
		return (NULL);
	
	// If not already loaded, load it now.
	if (Load() != PR_TRUE)
		return (NULL);

    return(PR_FindSymbol(m_instance, symbol));
}


// Component dll specific functions
nsresult nsDll::GetDllSpec(nsIFile **fsobj)
{
    NS_ASSERTION(m_dllSpec, "m_dllSpec NULL");
    NS_ASSERTION(fsobj, "xcDll::GetModule : Null argument" );

    *fsobj = m_dllSpec;
    NS_ADDREF(*fsobj);
    return NS_OK;
}

nsresult nsDll::GetModule(nsISupports *servMgr, nsIModule **cobj)
{
    // using the backpointer of the loader.
    nsIComponentManager* compMgr = m_loader->mCompMgr;
    NS_ASSERTION(compMgr, "Global Component Manager is null" );
    if (!compMgr) return NS_ERROR_UNEXPECTED;

    NS_ASSERTION(cobj, "xcDll::GetModule : Null argument" );

    if (m_moduleObject)
    {
        NS_ADDREF(m_moduleObject);
        *cobj = m_moduleObject;
        return NS_OK;
    }

	// If not already loaded, load it now.
	if (Load() != PR_TRUE) return NS_ERROR_FAILURE;

    // We need a nsIFile for location
    if (!m_dllSpec)
    {
        return NS_ERROR_FAILURE;
    }

    nsGetModuleProc proc =
      (nsGetModuleProc) FindSymbol(NS_GET_MODULE_SYMBOL);

    if (proc == NULL)
        return NS_ERROR_FACTORY_NOT_LOADED;

    nsresult rv = (*proc) (compMgr, m_dllSpec, &m_moduleObject);
    if (NS_SUCCEEDED(rv))
    {
        NS_ADDREF(m_moduleObject);
        *cobj = m_moduleObject;
    }
    return rv;
}


// These are used by BreakAfterLoad, below.
#ifdef SHOULD_IMPLEMENT_BREAKAFTERLOAD
static nsCString *sBreakList[16];
static int sBreakListCount = 0;
#endif

nsresult nsDll::Shutdown(void)
{
    // Release the module object if we got one
    nsrefcnt refcnt;
    if (m_moduleObject)
    {
        NS_RELEASE2(m_moduleObject, refcnt);
        NS_ASSERTION(refcnt == 0, "Dll moduleObject refcount non zero");
    }
#ifdef SHOULD_IMPLEMENT_BREAKAFTERLOAD
    for (int i = 0; i < sBreakListCount; i++)
    {
        delete sBreakList[i];
        sBreakList[i] = nsnull;
    }
    sBreakListCount = 0;
#endif
    return NS_OK;

}
#ifdef SHOULD_IMPLEMENT_BREAKAFTERLOAD
void nsDll::BreakAfterLoad(const char *nsprPath)
{
    static PRBool firstTime = PR_TRUE;

    // return if invalid input
    if (!nsprPath || !*nsprPath) return;

    // return if nothing to break on
    if (!firstTime && sBreakListCount == 0) return;

    if (firstTime)
    {
        firstTime = PR_FALSE;
        // Form the list of dlls to break on load
        nsCAutoString envList(getenv("XPCOM_BREAK_ON_LOAD"));
        if (envList.IsEmpty()) return;
        PRInt32 ofset = 0;
        PRInt32 start = 0;
        do
        {
            ofset = envList.FindChar(':', start);
            sBreakList[sBreakListCount] = new nsCString();
            envList.Mid(*(sBreakList[sBreakListCount]), start, ofset);
            sBreakListCount++;
            start = ofset + 1;
        }
        while (ofset != -1 && 16 > sBreakListCount); // avoiding vc6.0 compiler issue. count < thinks it is starting a template
    }

    // Find the dllname part of the string
    nsCString currentPath(nsprPath);
    PRInt32 lastSep = currentPath.RFindCharInSet(":\\/");

    for (int i=0; i<sBreakListCount; i++)
        if (currentPath.Find(*(sBreakList[i]), PR_TRUE, lastSep) > 0)
        {
            // Loading a dll that we want to break on
            // Put your breakpoint here
            fprintf(stderr, "...Loading module %s\n", nsprPath);
            // Break in the debugger here.
#if defined(__i386) && defined(__GNUC__)
            asm("int $3");
#elif defined(VMS)
            lib$signal(SS$_DEBUG);
#elif defined(XP_MACOSX)
            raise(SIGTRAP);
#endif
        }
    return;
}
#endif /* SHOULD_IMPLEMENT_BREAKAFTERLOAD */