namei_0.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"
/////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////
int sys_mkdir(const char * pathname)
{
	struct m_inode     * dir, * inode;
	struct buffer_head * bh , * dir_block;
	struct dir_entry   * de;
	const  char        * basename;
	int					 namelen;

	if (!(dir = dir_namei(pathname,&namelen,&basename)))
		return -1;
	if (!namelen) {
		iput(dir);
		return -1;
	}
	bh = find_entry(dir,basename,namelen,&de);
	if (bh) {
		brelse(bh);
		iput(dir);
		return -1;
	}
	inode = new_inode(dir->i_dev);
	if (!inode) {
		iput(dir);
		return -1;
	}

	if (!(inode->i_zone[0] = new_block(inode->i_dev))) {
		inode->i_nlinks--;
		iput(inode);
		iput(dir);
		return -1;
	}
	if (!(dir_block = bread(inode->i_dev,inode->i_zone[0],0))) {
		free_block(inode->i_dev,inode->i_zone[0]);
		inode->i_nlinks--;
		iput(inode);
		iput(dir);
		return -1;
	}

	de = (struct dir_entry *) dir_block->b_data;
	de->inode = inode->i_num;
	strcpy(de->name,".");		
	de++;
	de->inode = dir->i_num;
	strcpy(de->name,"..");		
	dir_block->b_dirt = 1;
	brelse(dir_block);

	bh = add_entry(dir,basename,namelen,&de);
	if (!bh) {
		free_block(inode->i_dev,inode->i_zone[0]);
		inode->i_nlinks--;
		iput(inode);
		iput(dir);
		return -1;
	}
	de->inode		= inode->i_num;
	bh->b_dirt		= 1;
	brelse(bh);

	inode->i_mode	= I_DIRECTORY;
	inode->i_nlinks = 2;
	inode->i_mtime	= file_datetime;
	inode->i_size	= 32;
	inode->i_dirt	= 1;
	iput(inode);

	dir->i_nlinks++;
	dir->i_mtime	= file_datetime;
	dir->i_dirt		= 1;
	iput(dir);

	return 0;
}

int empty_dir(struct m_inode * inode)
{
	struct buffer_head * bh;
	struct dir_entry   * de;
	int					 len,nr,block,new_block_flag;



	len = inode->i_size / sizeof(struct dir_entry);
	if ((len < 2) || (!inode->i_zone[0]) || !(bh = bread(inode->i_dev,inode->i_zone[0],0)))
		return 0;

	de = (struct dir_entry *) bh->b_data;
	if ((de[0].inode != inode->i_num) || (!de[1].inode) || strcmp(".",de[0].name) || strcmp("..",de[1].name)) {
		brelse(bh);
		return 0;
	}
	de += 2;

	new_block_flag = 0;
	nr = 2;
	while (nr < len) {
		if  (new_block_flag || ((void *)de >= (void *)(bh->b_data) + BLOCK_SIZE)) {
			brelse(bh);
			bh = NULL;
			block = bmap(inode , nr / DIR_ENTRIES_PER_BLOCK);
			if (!block) {
				nr += DIR_ENTRIES_PER_BLOCK;
				new_block_flag = 1;
				continue;
			}
			if (!(bh = bread(inode->i_dev,block,0)))
				return 0;
			de = (struct dir_entry *) bh->b_data;
			new_block_flag = 0;
		}
		if (de->inode) {
			brelse(bh);
			return 0;
		}
		de++;
		nr++;
	}
	brelse(bh);
	return 1;
}

int sys_rmdir(const char * name)
{
	struct m_inode     * dir, * inode;
	struct buffer_head * bh;
	struct dir_entry   * de;
	const char         * basename;
	int                  namelen;


	if (!(dir = dir_namei(name,&namelen,&basename)))
		return -1;
	if (!namelen) {
		iput(dir);
		return -1;
	}
	bh = find_entry(dir,basename,namelen,&de);
	if (!bh) {
		iput(dir);
		return -1;
	}

	if (!(inode = iget(dir->i_dev, de->inode))) {
		brelse(bh);
		iput(dir);
		return -1;
	}

	if ((inode == dir) || (inode == current_pwd) || (!S_ISDIR(inode->i_mode)) || (!empty_dir(inode))){	
		iput(inode);
		brelse(bh);
		iput(dir);
		return -1;
	}

	inode->i_nlinks = 0;
	inode->i_mtime	= file_datetime;
	inode->i_dirt   = 1;
	iput(inode);

	de->inode       = 0;
	bh->b_dirt      = 1;
	brelse(bh);

	dir->i_nlinks--;
	dir->i_mtime    = file_datetime;
	dir->i_dirt     = 1;
	iput(dir);

	return 0;
}