/*********************************************************************
 * Universal NetWare library stub.                                   *
 * written by Ulrich Neuman and given to OpenSource copyright-free.  *
 * version: 1.0                                                      *
 * $Id$
 *********************************************************************/

#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);
	}
}


