98 lines
2.5 KiB
C
98 lines
2.5 KiB
C
/*
|
|
* 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>
|
|
|
|
int sys_lseek(unsigned int fd,off_t offset, unsigned int origin)
|
|
{
|
|
struct file * file;
|
|
int tmp;
|
|
|
|
if (fd >= NR_OPEN || !(file=current->filp[fd]) || !(file->f_inode))
|
|
return -EBADF;
|
|
if (origin > 2)
|
|
return -EINVAL;
|
|
if (file->f_inode->i_pipe)
|
|
return -ESPIPE;
|
|
if (file->f_op && file->f_op->lseek)
|
|
return file->f_op->lseek(file->f_inode,file,offset,origin);
|
|
/* this is the default handler if no lseek handler is present */
|
|
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;
|
|
}
|
|
return file->f_pos;
|
|
}
|
|
|
|
int sys_read(unsigned int fd,char * buf,unsigned int count)
|
|
{
|
|
struct file * file;
|
|
struct inode * inode;
|
|
|
|
if (fd>=NR_OPEN || !(file=current->filp[fd]) || !(inode=file->f_inode))
|
|
return -EBADF;
|
|
if (!(file->f_mode & 1))
|
|
return -EBADF;
|
|
if (!count)
|
|
return 0;
|
|
verify_area(buf,count);
|
|
if (file->f_op && file->f_op->read)
|
|
return file->f_op->read(inode,file,buf,count);
|
|
/* these are the default read-functions */
|
|
if (inode->i_pipe)
|
|
return pipe_read(inode,file,buf,count);
|
|
if (S_ISCHR(inode->i_mode))
|
|
return char_read(inode,file,buf,count);
|
|
if (S_ISBLK(inode->i_mode))
|
|
return block_read(inode,file,buf,count);
|
|
if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode))
|
|
return minix_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,unsigned int count)
|
|
{
|
|
struct file * file;
|
|
struct inode * inode;
|
|
|
|
if (fd>=NR_OPEN || !(file=current->filp[fd]) || !(inode=file->f_inode))
|
|
return -EBADF;
|
|
if (!(file->f_mode&2))
|
|
return -EBADF;
|
|
if (!count)
|
|
return 0;
|
|
if (file->f_op && file->f_op->write)
|
|
return file->f_op->write(inode,file,buf,count);
|
|
/* these are the default read-functions */
|
|
if (inode->i_pipe)
|
|
return pipe_write(inode,file,buf,count);
|
|
if (S_ISCHR(inode->i_mode))
|
|
return char_write(inode,file,buf,count);
|
|
if (S_ISBLK(inode->i_mode))
|
|
return block_write(inode,file,buf,count);
|
|
if (S_ISREG(inode->i_mode))
|
|
return minix_file_write(inode,file,buf,count);
|
|
printk("(Write)inode->i_mode=%06o\n\r",inode->i_mode);
|
|
return -EINVAL;
|
|
}
|