You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
154 lines
3.4 KiB
154 lines
3.4 KiB
/*
|
|
* linux/fs/file_dev.c
|
|
*
|
|
* (C) 1991 Linus Torvalds
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/kernel.h>
|
|
#include <asm/segment.h>
|
|
#include <sys/types.h>
|
|
#include <new.h>
|
|
|
|
#define MIN(a,b) (((a)<(b))?(a):(b))
|
|
#define MAX(a,b) (((a)>(b))?(a):(b))
|
|
#define PATH_MAX 255
|
|
|
|
int file_read(struct m_inode * inode, struct file * filp, char * buf, int count)
|
|
{
|
|
int left,chars,nr;
|
|
struct buffer_head * bh;
|
|
|
|
if ((left=count)<=0)
|
|
return 0;
|
|
while (left) {
|
|
if (nr = bmap(inode,(filp->f_pos)/BLOCK_SIZE)) {
|
|
if (!(bh=bread(inode->i_dev,nr)))
|
|
break;
|
|
} else
|
|
bh = NULL;
|
|
nr = filp->f_pos % BLOCK_SIZE;
|
|
chars = MIN( BLOCK_SIZE-nr , left );
|
|
filp->f_pos += chars;
|
|
left -= chars;
|
|
if (bh) {
|
|
char * p = nr + bh->b_data;
|
|
while (chars-->0)
|
|
put_fs_byte(*(p++),buf++);
|
|
brelse(bh);
|
|
} else {
|
|
while (chars-->0)
|
|
put_fs_byte(0,buf++);
|
|
}
|
|
}
|
|
inode->i_atime = CURRENT_TIME;
|
|
return (count-left)?(count-left):-ERROR;
|
|
}
|
|
|
|
int file_write(struct m_inode * inode, struct file * filp, char * buf, int count)
|
|
{
|
|
off_t pos;
|
|
int block,c;
|
|
struct buffer_head * bh;
|
|
char * p;
|
|
int i=0;
|
|
|
|
/*
|
|
* ok, append may not work when many processes are writing at the same time
|
|
* but so what. That way leads to madness anyway.
|
|
*/
|
|
if (filp->f_flags & O_APPEND)
|
|
pos = inode->i_size;
|
|
else
|
|
pos = filp->f_pos;
|
|
while (i<count) {
|
|
if (!(block = create_block(inode,pos/BLOCK_SIZE)))
|
|
break;
|
|
if (!(bh=bread(inode->i_dev,block)))
|
|
break;
|
|
c = pos % BLOCK_SIZE;
|
|
p = c + bh->b_data;
|
|
bh->b_dirt = 1;
|
|
c = BLOCK_SIZE-c;
|
|
if (c > count-i) c = count-i;
|
|
pos += c;
|
|
if (pos > inode->i_size) {
|
|
inode->i_size = pos;
|
|
inode->i_dirt = 1;
|
|
}
|
|
i += c;
|
|
while (c-->0)
|
|
*(p++) = get_fs_byte(buf++);
|
|
brelse(bh);
|
|
}
|
|
inode->i_mtime = CURRENT_TIME;
|
|
if (!(filp->f_flags & O_APPEND)) {
|
|
filp->f_pos = pos;
|
|
inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
return (i?i:-1);
|
|
}
|
|
|
|
int sys_getdents(unsigned int fd, struct linux_dirent *d, unsigned int count)
|
|
{
|
|
struct linux_dirent tmp;
|
|
struct file * file;
|
|
struct m_inode * inode;
|
|
struct buffer_head * block;
|
|
struct dir_entry * ptr;
|
|
char * buf;
|
|
int bpos;
|
|
int dpos;
|
|
int ld_size;
|
|
int i;
|
|
|
|
ld_size = sizeof(struct linux_dirent); /* size of linux_dirent */
|
|
file = current->filp[fd]; /* opened file */
|
|
|
|
if (fd >= NR_OPEN)
|
|
return -EINVAL;
|
|
if (!count)
|
|
return -1;
|
|
if (!file)
|
|
return ENOTDIR;
|
|
|
|
inode = file->f_inode;
|
|
block = bread(inode->i_dev,inode->i_zone[0]);
|
|
|
|
/* count: size of linux_dirent[], target
|
|
* dd_size: size of dir_entry[], block 400?
|
|
*/
|
|
for (dpos = 0,bpos = 0;bpos<inode->i_size;bpos += sizeof(struct dir_entry)) {
|
|
if (dpos >= (count-ld_size))
|
|
return 0; /* d full */
|
|
ptr = (struct dir_entry *) (bpos + block->b_data);
|
|
if (!ptr -> inode)
|
|
continue; /* when it 's empty inode, jump it */
|
|
|
|
tmp.d_ino = ptr -> inode;
|
|
for (i = 0; i < 14; i++) tmp.d_name[i] = ptr -> name[i];
|
|
tmp.d_reclen = sizeof(tmp);
|
|
tmp.d_off = 0;
|
|
|
|
buf = &tmp;
|
|
for (i = 0; i < tmp.d_reclen; i++){
|
|
put_fs_byte(*(buf+i),((char*)d)+i+dpos); /* move data from kernel to user */
|
|
}
|
|
dpos += tmp.d_reclen;
|
|
}
|
|
return dpos;
|
|
}
|
|
|
|
long sys_mmap(void *start, size_t len, int prot, int flags,
|
|
int fd, off_t off)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int sys_munmap(void * start, size_t len)
|
|
{
|
|
return 0;
|
|
} |