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/*
* linux/fs/read_write.c
*
* (C) 1991 Linus Torvalds
*/
#include <sys/stat.h>
#include <errno.h>
#include <sys/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/segment.h>
extern int rw_char(int rw,int dev, char * buf, int count, off_t * pos);
extern int read_pipe(struct m_inode * inode, char * buf, int count);
extern int write_pipe(struct m_inode * inode, char * buf, int count);
extern int block_read(int dev, off_t * pos, char * buf, int count);
extern int block_write(int dev, off_t * pos, char * buf, int count);
extern int file_read(struct m_inode * inode, struct file * filp,
char * buf, int count);
extern int file_write(struct m_inode * inode, struct file * filp,
char * buf, int count);
int sys_lseek(unsigned int fd,off_t offset, int origin)
{
struct file * file;
int tmp;
if (fd >= NR_OPEN || !(file=current->filp[fd]) || !(file->f_inode)
|| !IS_SEEKABLE(MAJOR(file->f_inode->i_dev)))
return -EBADF;
if (file->f_inode->i_pipe)
return -ESPIPE;
switch (origin) {
case 0:
if (offset<0) return -EINVAL;
file->f_pos=offset;
break;
case 1:
if (file->f_pos+offset<0) return -EINVAL;
file->f_pos += offset;
break;
case 2:
if ((tmp=file->f_inode->i_size+offset) < 0)
return -EINVAL;
file->f_pos = tmp;
break;
default:
return -EINVAL;
}
return file->f_pos;
}
int sys_read(unsigned int fd,char * buf,int count)
{
struct file * file;
struct m_inode * inode;
if (fd>=NR_OPEN || count<0 || !(file=current->filp[fd]))
return -EINVAL;
if (!count)
return 0;
verify_area(buf,count);
inode = file->f_inode;
if (inode->i_pipe)
return (file->f_mode&1)?read_pipe(inode,buf,count):-EIO;
if (S_ISCHR(inode->i_mode))
return rw_char(READ,inode->i_zone[0],buf,count,&file->f_pos);
if (S_ISBLK(inode->i_mode))
return block_read(inode->i_zone[0],&file->f_pos,buf,count);
if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode)) {
if (count+file->f_pos > inode->i_size)
count = inode->i_size - file->f_pos;
if (count<=0)
return 0;
return file_read(inode,file,buf,count);
}
printk("(Read)inode->i_mode=%06o\n\r",inode->i_mode);
return -EINVAL;
}
int sys_write(unsigned int fd,char * buf,int count)
{
struct file * file;
struct m_inode * inode;
if (fd>=NR_OPEN || count <0 || !(file=current->filp[fd]))
return -EINVAL;
if (!count)
return 0;
inode=file->f_inode;
if (inode->i_pipe)
return (file->f_mode&2)?write_pipe(inode,buf,count):-EIO;
if (S_ISCHR(inode->i_mode))
return rw_char(WRITE,inode->i_zone[0],buf,count,&file->f_pos);
if (S_ISBLK(inode->i_mode))
return block_write(inode->i_zone[0],&file->f_pos,buf,count);
if (S_ISREG(inode->i_mode))
return file_write(inode,file,buf,count);
printk("(Write)inode->i_mode=%06o\n\r",inode->i_mode);
return -EINVAL;
}
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