/*********************************************************************
 * Universal NetWare library stub.                                   *
 * written by Ulrich Neuman and given to OpenSource copyright-free.  *
 * version: 1.0                                                      *
 * $Id: nwlibc.c,v 1.1.2.3 2007/09/09 19:44:24 guenter Exp $
 *********************************************************************/

#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <library.h>
#include <netware.h>
#include <screen.h>
#include <nks/thread.h>
#include <nks/synch.h>


typedef struct
{
    int     _errno;
    void    *twentybytes;
} libthreaddata_t;

typedef struct
{
    int         x;
    int         y;
    int         z;
    void        *tenbytes;
    NXKey_t     perthreadkey;   /* if -1, no key obtained... */
    NXMutex_t   *lock;
} libdata_t;

int         gLibId      = -1;
void        *gLibHandle = (void *) NULL;
rtag_t      gAllocTag   = (rtag_t) NULL;
NXMutex_t   *gLibLock   = (NXMutex_t *) NULL;

/* internal library function prototypes... */
int     DisposeLibraryData ( void * );
void    DisposeThreadData ( void * );
int     GetOrSetUpData ( int id, libdata_t **data, libthreaddata_t **threaddata );


int _NonAppStart
(
    void        *NLMHandle,
    void        *errorScreen,
    const char  *cmdLine,
    const char  *loadDirPath,
    size_t      uninitializedDataLength,
    void        *NLMFileHandle,
    int         (*readRoutineP)( int conn, void *fileHandle, size_t offset,
                                size_t nbytes, size_t *bytesRead, void *buffer ),
    size_t      customDataOffset,
    size_t      customDataSize,
    int         messageCount,
    const char  **messages
)
{
    NX_LOCK_INFO_ALLOC(liblock, "Per-Application Data Lock", 0);

#ifndef __GNUC__
#pragma unused(cmdLine)
#pragma unused(loadDirPath)
#pragma unused(uninitializedDataLength)
#pragma unused(NLMFileHandle)
#pragma unused(readRoutineP)
#pragma unused(customDataOffset)
#pragma unused(customDataSize)
#pragma unused(messageCount)
#pragma unused(messages)
#endif

/*
** Here we process our command line, post errors (to the error screen),
** perform initializations and anything else we need to do before being able
** to accept calls into us. If we succeed, we return non-zero and the NetWare
** Loader will leave us up, otherwise we fail to load and get dumped.
*/
    gAllocTag = AllocateResourceTag(NLMHandle,
                                "<library-name> memory allocations", AllocSignature);

    if (!gAllocTag)
    {
        OutputToScreen(errorScreen, "Unable to allocate resource tag for "
                                            "library memory allocations.\n");
        return -1;
    }

    gLibId = register_library(DisposeLibraryData);

    if (gLibId < -1)
    {
        OutputToScreen(errorScreen, "Unable to register library with kernel.\n");
        return -1;
    }

    gLibHandle = NLMHandle;

    gLibLock = NXMutexAlloc(0, 0, &liblock);

    if (!gLibLock)
    {
        OutputToScreen(errorScreen, "Unable to allocate library data lock.\n");
        return -1;
    }

    return 0;
}

/*
** Here we clean up any resources we allocated. Resource tags is a big part
** of what we created, but NetWare doesn't ask us to free those.
*/
void _NonAppStop( void )
{
    (void) unregister_library(gLibId);
    NXMutexFree(gLibLock);
}

/*
** This function cannot be the first in the file for if the file is linked
** first, then the check-unload function's offset will be nlmname.nlm+0
** which is how to tell that there isn't one. When the check function is
** first in the linked objects, it is ambiguous. For this reason, we will
** put it inside this file after the stop function.
**
** Here we check to see if it's alright to ourselves to be unloaded. If not,
** we return a non-zero value. Right now, there isn't any reason not to allow
** it.
*/
int  _NonAppCheckUnload( void )
{
    return 0;
}

int GetOrSetUpData
(
    int                 id,
    libdata_t           **appData,
    libthreaddata_t **threadData
)
{
    int                 err;
    libdata_t           *app_data;
    libthreaddata_t *thread_data;
    NXKey_t             key;
    NX_LOCK_INFO_ALLOC(liblock, "Application Data Lock", 0);

    err         = 0;
    thread_data = (libthreaddata_t *) NULL;

/*
** Attempt to get our data for the application calling us. This is where we
** store whatever application-specific information we need to carry in support
** of calling applications.
*/
    app_data = (libdata_t *) get_app_data(id);

    if (!app_data)
    {
/*
** This application hasn't called us before; set up application AND per-thread
** data. Of course, just in case a thread from this same application is calling
** us simultaneously, we better lock our application data-creation mutex. We
** also need to recheck for data after we acquire the lock because WE might be
** that other thread that was too late to create the data and the first thread
** in will have created it.
*/
        NXLock(gLibLock);

        if (!(app_data = (libdata_t *) get_app_data(id)))
        {
            app_data = (libdata_t *) malloc(sizeof(libdata_t));

            if (app_data)
            {
                memset(app_data, 0, sizeof(libdata_t));

                app_data->tenbytes = malloc(10);
                app_data->lock     = NXMutexAlloc(0, 0, &liblock);

                if (!app_data->tenbytes || !app_data->lock)
                {
                    if (app_data->lock)
                        NXMutexFree(app_data->lock);

                    free(app_data);
                    app_data = (libdata_t *) NULL;
                    err      = ENOMEM;
                }

                if (app_data)
                {
/*
** Here we burn in the application data that we were trying to get by calling
** get_app_data(). Next time we call the first function, we'll get this data
** we're just now setting. We also go on here to establish the per-thread data
** for the calling thread, something we'll have to do on each application
** thread the first time it calls us.
*/
                    err = set_app_data(gLibId, app_data);

                    if (err)
                    {
                        free(app_data);
                        app_data = (libdata_t *) NULL;
                        err      = ENOMEM;
                    }
                    else
                    {
                        /* create key for thread-specific data... */
                        err = NXKeyCreate(DisposeThreadData, (void *) NULL, &key);

                        if (err)                /* (no more keys left?) */
                            key = -1;

                        app_data->perthreadkey = key;
                    }
                }
            }
        }

        NXUnlock(gLibLock);
    }

    if (app_data)
    {
        key = app_data->perthreadkey;

        if (     key != -1                  /* couldn't create a key? no thread data */
            && !(err = NXKeyGetValue(key, (void **) &thread_data))
            && !thread_data)
        {
/*
** Allocate the per-thread data for the calling thread. Regardless of whether
** there was already application data or not, this may be the first call by a
** a new thread. The fact that we allocation 20 bytes on a pointer is not very
** important, this just helps to demonstrate that we can have arbitrarily
** complex per-thread data.
*/
            thread_data = (libthreaddata_t *) malloc(sizeof(libthreaddata_t));

            if (thread_data)
            {
                thread_data->_errno      = 0;
                thread_data->twentybytes = malloc(20);

                if (!thread_data->twentybytes)
                {
                    free(thread_data);
                    thread_data = (libthreaddata_t *) NULL;
                    err         = ENOMEM;
                }

                if ((err = NXKeySetValue(key, thread_data)))
                {
                    free(thread_data->twentybytes);
                    free(thread_data);
                    thread_data = (libthreaddata_t *) NULL;
                }
            }
        }
    }

    if (appData)
        *appData = app_data;

    if (threadData)
        *threadData = thread_data;

    return err;
}

int DisposeLibraryData
(
    void    *data
)
{
    if (data)
    {
        void    *tenbytes = ((libdata_t *) data)->tenbytes;

        if (tenbytes)
            free(tenbytes);

        free(data);
    }

    return 0;
}

void DisposeThreadData
(
    void    *data
)
{
    if (data)
    {
        void    *twentybytes = ((libthreaddata_t *) data)->twentybytes;

        if (twentybytes)
            free(twentybytes);

        free(data);
    }
}


