zfschdir.c

zilog的实时操作系统RZK,可以移植到多种处理器上

/*
 * File       : ZFSChdir.c
 * Description: This file contains the implementation of ZFSChdir API
 * Author     : Mahadev K C
 * Created on : 30-APR-2003
 *
 * Copyright 2004 ZiLOG Inc.  ALL RIGHTS RESERVED.
 *
 * This file contains unpublished confidential and proprietary information
 * of ZiLOG, Inc.
 * NO PART OF THIS WORK MAY BE DUPLICATED, STORED, PUBLISHED OR DISCLOSED 
 * IN ANY FORM WITHOUT THE PRIOR WRITTEN CONSENT OF ZiLOG, INC.
 * This is not a license and no use of any kind of this work is authorized
 * in the absence of a written license granted by ZiLOG, Inc. in ZiLOG's 
 * sole discretion 
 */


#include "ZSysgen.h"
#include "ZTypes.h"
#include "ZThread.h"
#include "ZSemaphore.h"
#include "glextern.h"
extern RZK_SEMAPHOREHANDLE_t hSem_FS;

INT GetCwdLenForNode( PZFS_DIR_LIST_t pdir_node )
{
	UINT len ;
	UINT ttl_len = 0 ;
	PZFS_DIR_LIST_t proot_node ;
	UINT8 begin = ZFS_TRUE ;

	for( proot_node = pdir_node ; proot_node->up_list != NULL ; proot_node = proot_node->up_list ) ;
	
	while ( pdir_node != NULL )
		{

		// get the pdir_node and get the length of the name.
		len = strlen( ( const INT8 *) pdir_node->dir_name ) ;
		ttl_len += len ;

		if( pdir_node == proot_node && begin == ZFS_TRUE )
			{
			ttl_len += 3 ;
			goto end_GetCwdLenForNode ;
			}
		else
			begin = ZFS_FALSE ;

		if( pdir_node == proot_node )
			ttl_len += 2 ; // needed for :/
		else
			ttl_len++ ;

		pdir_node = pdir_node->up_list ;
		}
end_GetCwdLenForNode:
	return ttl_len ;

}


VOID GetCwdStringForDirNode( PZFS_DIR_LIST_t pdir_node, INT8 *pcwd_path)
{
	UINT len = 0 ;
	UINT idx ;
	UINT ttl_len = 0 ;
	PZFS_DIR_LIST_t proot_node ;
	INT8 *pend, *pcur ;
	UINT8 begin = ZFS_TRUE ;

	for( proot_node = pdir_node ; proot_node->up_list != NULL ; proot_node = proot_node->up_list ) ;

	while( pdir_node != NULL )
		{

		len = strlen( (const INT8 * ) pdir_node->dir_name ) ;

		// if this is the first time, just copy the data onto the buffer.
		if( begin == ZFS_TRUE )
			{
			if( pdir_node != proot_node )
				memcpy( &pcwd_path[1], pdir_node->dir_name, len ) ;
			else
				{
				memcpy( &pcwd_path[0], pdir_node->dir_name, len ) ;
				pcwd_path[len]=':' ;
				pcwd_path[len+1]='/' ;	// to support '/'
//			pcwd_path[len+1]='\\' ;		// to support '\'
				ttl_len += len + 2 ;
				goto end_GetCwdStringForDirNode ;
				}
			begin = ZFS_FALSE ;
			ttl_len = len + 1;
			}
		else
			{
			// shift the bytes to right.
			pend = pcwd_path + ttl_len + len ;
			pcur = pcwd_path + ttl_len - 1;

			for( idx = 0 ; idx < ttl_len ; idx++ )
				{
				*pend = *pcur ;
				pend-- ;
				pcur-- ;
				}
			if( proot_node == pdir_node )
				memcpy( &pcwd_path[0], pdir_node->dir_name, len ) ;
			else
				memcpy( &pcwd_path[1], pdir_node->dir_name, len ) ;
			ttl_len += len + 1;
			}
		if( proot_node == pdir_node )
			pcwd_path[len] = ':';
		else
			{
			pcwd_path[0]='/' ;	// to support '/'
//			pcwd_path[0]='\\' ;	// to support '\'
			}

		pdir_node = pdir_node->up_list ;
		}

end_GetCwdStringForDirNode:
	pcwd_path[ ttl_len ] = '\0' ;
}


	

extern RZK_SEMAPHOREHANDLE_t hSem_FS;
//Function Name: ZFSChdir
//Decription: This API changes the current working directory to a new directory provided in 
// the arguments
ZFS_STATUS_t ZFSChdir( IN INT8 *dir )
{
	UINT off = 0 ;
	UINT len = 0 ;
	PZFS_DIR_LIST_t pdir_node, pcwd_dir_node ;
	PZFS_VOL_INFO_t pvol_info ;
	UINT8 status ;
	INT8 *pcwd_path ;
	ZFS_STATUS_t ret_status = ZFSERR_SUCCESS  ;
	
	// if ZFS is not initialized, return error
	if( !IsZFSInited() )
		return ZFSERR_NOT_INITIALIZED ;

	// now check the validity of the dir path given in the argument
	if( !ValidatePath( dir ) )
		return ZFSERR_INVALID_FILEDIR_PATH ;

	// get the length of the dir name
	len = strlen( ( const INT8 * ) dir ) ;

	// disable preemption
//	preempt_status = DisablePreemption() ;
	RZKAcquireSemaphore(hSem_FS,INFINITE_SUSPEND);
	if( GetCwdInfoForCurThread( &pvol_info, &pcwd_dir_node )  != ZFS_TRUE )
		{
		ret_status = ZFSERR_INVALID_VOLUME ;
		goto err_label_ZFS_Chdir ;
		}

	// now validated, disable preemption, find the absolute path 
	status = IsAbsPath( dir, &pvol_info, &off, &pdir_node ) ;
	if( status != ZFS_TRUE )
		{
		ret_status = ZFSERR_INVALID_FILEDIR_PATH ;
		goto err_label_ZFS_Chdir ;
		}

	if( !IsVolumeValid(pvol_info) )
		{
		ret_status = ZFSERR_INVALID_VOLUME ;
		goto err_label_ZFS_Chdir ;
		}
	
		
	if( pdir_node == NULL )
		{
		pdir_node = pcwd_dir_node ;
		}
	
		// this is relative path, get the directory node of the relative path
	pdir_node = GetNodeForPath( pdir_node, dir + off, ( len - off ) ) ;
	if( pdir_node == NULL )
		{
		ret_status = ZFSERR_INVALID_FILEDIR_PATH ;
		goto err_label_ZFS_Chdir ;
		}

	// Now Need to check the length of the new directory path. If it is less
	// than the max_dir_length, then only set otherwise return an error.
	if(  GetCwdLenForNode( pdir_node ) > g_max_cwd_len )
		{
		ret_status = ZFSERR_CWD_PATH_LENGTH_MORE ;
		goto err_label_ZFS_Chdir ;
		}

	// prepare the CWD string and store it in the thread TCB

	pcwd_path = GetCwdPathForHandle( GetCurrentThread() ) ;

	GetCwdStringForDirNode( pdir_node, pcwd_path ) ;

	// now set the path in the string
	SetCwdPath( pcwd_path ) ;

err_label_ZFS_Chdir:	
	RZKReleaseSemaphore(hSem_FS);
//	EnablePreemption( preempt_status ) ;
	return ret_status ;
}