/*************************************************************************
* (C) 2008 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
*  by Michael Pounov <misho@openbsd-bg.org>
*
* $Author: misho $
* $Id: aitsess.c,v 1.3 2011/09/07 13:11:56 misho Exp $
*
**************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
*/
#include "global.h"
#include "aitsess.h"


#pragma GCC visibility push(hidden)

int sess_Errno;
char sess_Error[STRSIZ];

#pragma GCC visibility pop

// -----------------------------------------------------------

// Error maintenance functions ...

// sess_GetErrno() Get error code of last operation
inline int
sess_GetErrno()
{
	return sess_Errno;
}
// sess_GetError() Get error text of last operation
inline const char *
sess_GetError()
{
	return sess_Error;
}
// sess_SetErr() Set error to variables for internal use!!!
inline void
sess_SetErr(int eno, char *estr, ...)
{
	va_list lst;

	sess_Errno = eno;
	memset(sess_Error, 0, sizeof sess_Error);
	va_start(lst, estr);
	vsnprintf(sess_Error, sizeof sess_Error, estr, lst);
	va_end(lst);
}

// -----------------------------------------------------------

/*
 * initSession() Initializing session structure, if session file not exists creating with specified tech
 * @pnID = Technology using in session. 
 	SHARED_IPC IPC tech; SHARED_MAP BSD MemoryMap tech or if =NULL SHARED_IPC
 * @csFName = Session filename for build key and identified
 * @Sess = Session item, if =NULL allocate memory for session after use must be free!
 * return: 0 OK new key created, -1 error: no memory or file not created, 1 OK key finded
*/
inline int
initSession(int *pnID, const char *csFName, tagSess ** __restrict Sess)
{
	int h, ret = 0, id = SHARED_IPC;
	char szStr[STRSIZ];

	if (!*Sess) {
		*Sess = malloc(sizeof(tagSess));
		if (!*Sess) {
			LOGERR;
			return -1;
		}
	} else
		memset(*Sess, 0, sizeof(tagSess));
	if (pnID && *pnID)
		id = *pnID;

	h = open(csFName, O_WRONLY | O_CREAT | O_EXCL, MEM_MODE);
	if (h == -1) {
		if (errno != EEXIST) {
			LOGERR;
			free(*Sess);
			return -1;
		}
		/* If key file exist, session already connected */
		h = open(csFName, O_RDONLY);
		if (h == -1) {
			LOGERR;
			free(*Sess);
			return -1;
		}
		ret = read(h, szStr, sizeof szStr);
		if (ret == -1) {
			LOGERR;
			close(h);
			free(*Sess);
			return -1;
		}
		if (!strncmp(szStr, "IPC@", 4))
			id = SHARED_IPC;
		else if (!strncmp(szStr, "MAP@", 4))
			id = SHARED_MAP;
		else {
			sess_SetErr(EPROTONOSUPPORT, "Error:: Session type not supported");
			close(h);
			free(*Sess);
			return -1;
		}

		ret = 1;	/* key found */
	} else {
		/* Build new key & new session */
		switch (id) {
			case SHARED_IPC:
				strlcpy(szStr, "IPC@", sizeof szStr);
				break;
			case SHARED_MAP:
				strlcpy(szStr, "MAP@", sizeof szStr);
				break;
			default:
				sess_SetErr(EPROTONOSUPPORT, "Error:: Session type not supported");
				close(h);
				unlink(csFName);
				free(*Sess);
				return -1;
		}
		strlcat(szStr, "ELWIX_Session ("PACKAGE_STRING")\n", sizeof szStr);
		write(h, szStr, strlen(szStr));

		ret = 0;	/* new key created */
	}
	close(h);

	(*Sess)->type = id;
	return ret;
}

/*
 * freeSession() Free allocated memory for session item and delete session file if present name
 * @csFName = Session filename for delete, if NULL nothing delete
 * @Sess = Session item
*/
inline void
freeSession(const char *csFName, tagSess ** __restrict Sess)
{
	assert(Sess);
	if (!Sess)
		return;

	(*Sess)->type = SHARED_UNKNOWN;
	if (csFName)
		unlink(csFName);
	if (*Sess)
		free(*Sess);
	*Sess = NULL;
}


/*
 * map_createSession() MMAP Created session and allocated resources
 * @csFName = Session name for identified
 * @cnSeed = Seed for securing key
 * @cnSize = Allocated shared memory size in bytes
 * @Sess = Session item
 * return: 0 Ok successful, -1 error: not allocated resources
*/
int
map_createSession(const char *csFName, const int cnSeed, const u_int cnSize, tagSess ** __restrict Sess)
{
	int ret = 0, id = SHARED_MAP;
	char szSName[2][FILENAME_MAX];

	ret = initSession(&id, csFName, Sess);
	if (ret == -1 || !*Sess)
		return -1;

	/* genkey */
	(*Sess)->key = ftok(csFName, cnSeed);
	if ((*Sess)->key == -1) {
		LOGERR;
		freeSession(csFName, Sess);
		return -1;
	}

	/* build semaphore & shared memory name */
	memset(szSName, 0, sizeof szSName);
	snprintf(szSName[0], MAX_SEMNAME, "/%X.ANS", (u_int) (*Sess)->key);
	snprintf(szSName[1], FILENAME_MAX, "%s-%x.ANM", csFName, (u_int) (*Sess)->key);

	/* create semaphore & add 1 */
	(*Sess)->id.sid = sem_open(szSName[0], O_CREAT, MEM_MODE);
	if ((*Sess)->id.sid == SEM_FAILED) {
		LOGERR;
		map_destroySession(csFName, Sess);
		return -1;
	} else
		sem_post((*Sess)->id.sid);

	/* create file for shared memory storage */
	(*Sess)->mem.fd = open(szSName[1], O_RDWR | O_CREAT, MEM_MODE);
	if ((*Sess)->mem.fd == -1) {
		LOGERR;
		map_destroySession(csFName, Sess);
		return -1;
	}
	/* if is new shared memory session, fill file with zeros */
	if (!ret) {
		if (lseek((*Sess)->mem.fd, cnSize - 1, SEEK_SET) == -1) {
			LOGERR;
			map_destroySession(csFName, Sess);
			return -1;
		} else
			write((*Sess)->mem.fd, "", 1);
		lseek((*Sess)->mem.fd, 0, SEEK_SET);
	}
	(*Sess)->eom = cnSize;

	return ret;
}

/*
 * map_destroySession() MMAP free shared resources
 * @csFName = Session name for delete
 * @Sess = Session item
*/
void
map_destroySession(const char *csFName, tagSess ** __restrict Sess)
{
	int flg = 1;
	char szSName[2][FILENAME_MAX];

	assert(Sess);
	if (!Sess || !*Sess)
		return;

	memset(szSName, 0, sizeof szSName);
	snprintf(szSName[0], MAX_SEMNAME, "/%X.ANS", (u_int) (*Sess)->key);
	snprintf(szSName[1], FILENAME_MAX, "%s-%x.ANM", csFName, (u_int) (*Sess)->key);

	if ((*Sess)->id.sid != SEM_FAILED) {
		if (sem_close((*Sess)->id.sid) == -1)
			flg = 0;
		if (sem_unlink(szSName[0]) == -1)
			/*flg = 0*/;
	}
	if ((*Sess)->mem.fd != -1) {
		if (close((*Sess)->mem.fd) == -1)
			flg = 0;
		if (unlink(szSName[1]) == -1)
			/*flg = 0*/;
	}
	(*Sess)->eom ^= (*Sess)->eom;

	freeSession(flg ? csFName : NULL, Sess);
}

/*
 * ipc_createSession() IPC Created session and allocated resources
 * @csFName = Session name for identified
 * @cnSeed = Seed for securing key
 * @cnSize = Allocated shared memory size in bytes
 * @Sess = Session item
 * return: 0 Ok successful, -1 error: not allocated resources
*/
int
ipc_createSession(const char *csFName, const int cnSeed, const u_int cnSize, tagSess ** __restrict Sess)
{
	int ret = 0, id = SHARED_IPC;
	union semun sems;

	ret = initSession(&id, csFName, Sess);
	if (ret == -1 || !*Sess)
		return -1;

	/* genkey */
	(*Sess)->key = ftok(csFName, cnSeed);
	if ((*Sess)->key == -1) {
		LOGERR;
		freeSession(csFName, Sess);
		return -1;
	}

	/* create semaphore */
	(*Sess)->id.semid = semget((*Sess)->key, 1, MEM_MODE | IPC_CREAT);
	if ((*Sess)->id.semid == -1) {
		LOGERR;
		ipc_destroySession(csFName, Sess);
		return -1;
	}
	/* if is new shared memory session, init sempahore with 1 */
	if (!ret) {
		sems.val = 1;
		if (semctl((*Sess)->id.semid, 0, SETVAL, sems) == -1) {
			LOGERR;
			ipc_destroySession(csFName, Sess);
			return -1;
		}
	}

	/* create shared memory object */
	(*Sess)->mem.shmid = shmget((*Sess)->key, cnSize, MEM_MODE | IPC_CREAT);
	if ((*Sess)->mem.shmid == -1) {
		LOGERR;
		ipc_destroySession(csFName, Sess);
		return -1;
	}
	(*Sess)->eom = cnSize;

	return ret;
}

/*
 * ipc_destroySession() IPC free shared resources
 * @csFName = Session name for delete
 * @Sess = Session item
*/
void
ipc_destroySession(const char *csFName, tagSess ** __restrict Sess)
{
	int flg = 1;
	union semun sems;
	struct shmid_ds ds;

	assert(Sess);
	if (!Sess || !*Sess)
		return;

	if ((*Sess)->id.semid != -1)
		if (semctl((*Sess)->id.semid, 0, IPC_RMID, &sems) == -1)
			flg = 0;
	if ((*Sess)->mem.shmid != -1)
		if (shmctl((*Sess)->mem.shmid, IPC_RMID, &ds) == -1)
			flg = 0;
	(*Sess)->eom ^= (*Sess)->eom;

	freeSession(flg ? csFName : NULL, Sess);
}


/*
 * map_attachSession() MMAP Attach to shared memory & return begin address
 * @s = Session item
 * @procMem = Custom start address (optionl) *default must be 0*
 * return: NULL failed attach, !=NULL begin address of memory
*/
inline void *
map_attachSession(tagSess * __restrict s, void *procMem)
{
	struct stat sb;

	if (!s)
		return NULL;

	/* Learn size of shared memory block */
	sync();
	if (fstat(s->mem.fd, &sb) == -1) {
		LOGERR;
		return NULL;
	} else
		s->eom = sb.st_size;

	/* attach to memory */
	s->addr = mmap(procMem, s->eom, PROT_READ | PROT_WRITE, MAP_SHARED, s->mem.fd, 0);
	if (s->addr == MAP_FAILED) {
		LOGERR;
		s->addr = NULL;
	}

	return s->addr;
}

/*
 * map_detachSession() MMAP Detach from shared memory
 * @s = Session item
*/
inline void
map_detachSession(tagSess * __restrict s)
{
	if (!s)
		return;

	msync(s->addr, 0, MS_SYNC | MS_INVALIDATE);

	if (s->addr && s->eom) {
		munmap(s->addr, s->eom);
		s->addr = NULL;
	}
}

/*
 * ipc_attachSession() IPC Attach to shared memory & return begin address
 * @s = Session item
 * @procMem = Custom start address (optionl) *default must be 0*
 * return: NULL failed attach, !=NULL begin address of memory
*/
inline void *
ipc_attachSession(tagSess * __restrict s, void *procMem)
{
	if (!s)
		return NULL;

	s->addr = shmat(s->mem.shmid, procMem, 0);
	if (s->addr == (void*) -1) {
		LOGERR;
		s->addr = NULL;
	}

	return s->addr;
}

/*
 * ipc_detachSession() IPC Detach from shared memory
 * @s = Session item
*/
inline void
ipc_detachSession(tagSess * __restrict s)
{
	if (!s)
		return;

	if (s->addr) {
		shmdt(s->addr);
		s->addr = NULL;
	}
}

/*
 * isAttached() Check for mapped/(attached) shared memory
 * @s = Session item
 * return: -1 null session item, 0 not attached, 1 attached memory
*/
inline int
isAttached(tagSess * __restrict s)
{
	if (!s)
		return -1;

	return (s->addr ? 1 : 0);
}


/*
 * map_notSemaphore() MMAP negative block if semaphore isn`t signaled
 * @s = Session item
*/
inline void
map_notSemaphore(tagSess * __restrict s)
{
	int i = -1;

	if (!s)
		return;

	sem_getvalue(s->id.sid, &i);
	for (;i > 0; i--)
		sem_wait(s->id.sid);
}

/*
 * map_isSemaphored() MMAP Check semaphore
 * @s = Session item
 * return: -1 error: can`t return semaphore, 0 = false, 1 = true
*/
inline int
map_isSemaphored(tagSess * __restrict s)
{
	int val = -1;

	if (!s)
		return -1;

	sem_getvalue(s->id.sid, &val);
	return val ? 0 : 1;
}

/*
 * map_addSemaphore() MMAP unblock semaphore, increment semaphore
 * @s = Session item
 * return: 0 Ok, -1 error: can`t increment 
*/
inline int
map_addSemaphore(tagSess * __restrict s)
{
	if (!s)
		return -1;

	return sem_post(s->id.sid);
}

/*
 * map_decSemaphore() MMAP block semaphore, decrement semaphore
 * @s = Session item
 * return: 0 Ok, -1 error: can`t decrement 
*/
inline int
map_decSemaphore(tagSess * __restrict s)
{
	if (!s)
		return -1;

	return sem_wait(s->id.sid);
}

/*
 * ipc_notSemaphore() IPC negative block if semaphore isn`t signaled
 * @s = Session item
*/
inline void
ipc_notSemaphore(tagSess * __restrict s)
{
	struct sembuf sb = { 0, 0, 0 };

	if (s)
		semop(s->id.semid, &sb, 1);
}

/*
 * ipc_isSemaphored() IPC Check semaphore
 * @s = Session item
 * return: -1 error: can`t return semaphore, 0 = false, 1 = true
*/
inline int
ipc_isSemaphored(tagSess * __restrict s)
{
	struct sembuf sb = { 0, 0, IPC_NOWAIT };

	if (!s)
		return -1;

	return semop(s->id.semid, &sb, 1) + 1;
}

/*
 * ipc_addSemaphore() IPC unblock semaphore, increment semaphore
 * @s = Session item
 * return: 0 Ok, -1 error: can`t increment 
*/
inline int
ipc_addSemaphore(tagSess * __restrict s)
{
	struct sembuf sb = { 0, 1, 0 };

	if (!s)
		return -1;

	return semop(s->id.semid, &sb, 1);
}

/*
 * ipc_decSemaphore() IPC block semaphore, decrement semaphore
 * @s = Session item
 * return: 0 Ok, -1 error: can`t decrement 
*/
inline int
ipc_decSemaphore(tagSess * __restrict s)
{
	struct sembuf sb = { 0, -1, 0 };

	if (!s)
		return -1;

	return semop(s->id.semid, &sb, 1);
}