msdos_namei.c

阿基米德操作系统的源代码

///////////////////////////////////////////////////////////////////////////////////////////////
#include "general.h"
#include "s_isdirreg.h"

#include "hd_info_struct.h"
#include "dir_entry.h"
#include "msdos_dir_entry.h"
#include "d_inode.h"
#include "m_inode.h"
#include "buffer_head.h"
#include "fat_cache.h"
#include "file.h"
#include "hd_request_struct.h"
#include "super_block.h"

#include "common_head.h"
///////////////////////////////////////////////////////////////////////////////////////////////
struct m_inode * msdos_get_dir(const char * pathname)
{
	struct m_inode			* temp_inode;
	struct buffer_head		* temp_bh;
	struct msdos_dir_entry  * temp_de;
	const  char				* thisname;
	char					  c;
	unsigned long			  temp_idev,temp_inr,temp_namelen;
	int						  temp_i, temp_flag;

	if (!current_root || !current_root->i_count || !current_pwd || !current_pwd->i_count)
		return NULL;

	if ((c = get_gs_byte(pathname)) == '\\') {
		temp_inode = current_root;
		pathname++;
		for (temp_i = 0; temp_i <= current_root_pathlength; temp_i++)
			current_path[temp_i] = current_root_path[temp_i];
		current_pathlength  = current_root_pathlength;
	} else if (c) {
		temp_inode = current_pwd;
		for (temp_i = 0; temp_i <= current_pwd_pathlength; temp_i++)
			current_path[temp_i] = current_pwd_path[temp_i];
		current_pathlength  = current_pwd_pathlength;
	}
	else
		return NULL;	

	temp_inode->i_count++;
	while (1) {
		thisname = pathname;
		if (!S_MSDOS_ISDIR(temp_inode->i_mode))
		{	
			msdos_iput(temp_inode);
			return NULL;
		}
		for(temp_namelen = 0 , current_namelen = 0 ; (c = get_gs_byte(pathname++)) && (c != '\\') ; temp_namelen++, current_namelen++)
		{
			if (current_namelen < MSDOS_NAME_LEN + 1)
				current_name[current_namelen] = c;
			current_path[current_pathlength + temp_namelen + 1] = c;
		}
		current_path[current_pathlength + temp_namelen + 1] = c;

		if (!c)
			return temp_inode;

		if (!change_current_name())
		{
			msdos_iput(temp_inode);
			return NULL;
		}

		if ((current_dir_type == 1) && (temp_inode == current_root))
			continue;

		if (!(temp_bh = msdos_find_entry(temp_inode,&temp_de)))
		{
			msdos_iput(temp_inode);
			return NULL;
		}

		current_dir_entry	= *temp_de;
		temp_idev = 0;
		temp_inr  =  temp_bh->b_blocknr * BLOCK_SIZE + ((unsigned long)temp_de) - ((unsigned long)(temp_bh->b_data));
		srelse(temp_bh);
		msdos_iput(temp_inode);

		if (S_MSDOS_ISLABEL(current_dir_entry.dir_mode))
			return NULL;

		temp_flag = 0;
		switch (current_dir_type)
		{
		case 0:
				current_path[current_pathlength + temp_namelen + 1] = current_pathlength;
				current_pathlength = current_pathlength + temp_namelen + 1;
				break;
		case 1:
				break;
		case 2:
				temp_flag = 1;
				current_pathlength = current_path[current_pathlength];
				break;
		}

		if (!(temp_inode = msdos_iget(&current_dir_entry,temp_inr,temp_flag)))
			return NULL;
	}
	return NULL;
}

////////////////////////////////////////////////////////////////////////////////////////////

struct m_inode * msdos_dir_namei(const char * pathname, int * namelen, const char ** name)
{
	struct m_inode * temp_dir;
	const char     * basename;
	char             c;

	if (!(temp_dir = msdos_get_dir(pathname)))
		return NULL;
	basename = pathname;
	while ((c = get_gs_byte(pathname++)) != 0)
		if (c == '\\')
			basename = pathname;

	*namelen = (int)(pathname - basename - 1);
	*name    = basename;
	return temp_dir;
}

struct m_inode * msdos_namei(const char * pathname)
{
	struct m_inode			* temp_dir;
	struct buffer_head		* temp_bh;
	struct msdos_dir_entry  * temp_de;
	const char				* basename;
	unsigned long			  temp_idev,temp_inr,temp_namelen;
	int						  temp_flag;

	if (!(temp_dir = msdos_dir_namei(pathname,&temp_namelen,&basename)))
		return NULL;
	if (!temp_namelen)			/* special case: '/usr/' etc */
		return temp_dir;

	if (!change_current_name())
	{
		msdos_iput(temp_dir);
		return NULL;
	}

	if ((current_dir_type == 1) && (temp_dir == current_root))
		return temp_dir;

	if (!(temp_bh = msdos_find_entry(temp_dir,&temp_de)))
	{
		msdos_iput(temp_dir);
		return NULL;
	}

	current_dir_entry	= *temp_de;
	temp_idev	= 0;
	temp_inr	= temp_bh->b_blocknr * BLOCK_SIZE + ((unsigned long)temp_de) - ((unsigned long)(temp_bh->b_data));
	srelse(temp_bh);
	msdos_iput(temp_dir);

	if (S_MSDOS_ISLABEL(current_dir_entry.dir_mode))
		return NULL;

	temp_flag = 0;
	switch (current_dir_type)
	{
	case 0:
			current_path[current_pathlength + temp_namelen + 1] = current_pathlength;
			current_pathlength = current_pathlength + temp_namelen + 1;
			break;
	case 1:
			break;
	case 2:
			temp_flag = 1;
			current_pathlength = current_path[current_pathlength];
			break;
	}

	temp_dir = msdos_iget(&current_dir_entry,temp_inr,temp_flag);
	return temp_dir;
}