struct inode *get_pipe_inode(void)
{
register struct inode *inode;
extern struct inode_operations pipe_inode_operations;
if ((inode = get_empty_inode())) {
if (!(PIPE_BASE(*inode) = get_pipe_mem())) {
iput(inode);
return NULL;
}
inode->i_op = &pipe_inode_operations;
inode->i_count = 2; /* sum of readers/writers */
PIPE_START(*inode) = PIPE_LEN(*inode) = 0;
PIPE_RD_OPENERS(*inode) = PIPE_WR_OPENERS(*inode) = 0;
PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1;
PIPE_LOCK(*inode) = 0;
inode->i_pipe = 1;
inode->i_mode |= S_IFIFO | S_IRUSR | S_IWUSR;
inode->i_uid = current->euid;
inode->i_gid = (__u8) current->egid;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
#if 0
inode->i_blksize = PAGE_SIZE;
#endif
}
return inode;
}
static int pipe_rdwr_open(register struct inode *inode,
register struct file *filp)
{
debug("PIPE: rdwr called.\n");
if(!PIPE_BASE(*inode)) {
if(!(PIPE_BASE(*inode) = get_pipe_mem()))
return -ENOMEM;
#if 0
/* next fields already set to zero by get_empty_inode() */
PIPE_START(*inode) = PIPE_LEN(*inode) = 0;
PIPE_RD_OPENERS(*inode) = PIPE_WR_OPENERS(*inode) = 0;
PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 0;
PIPE_LOCK(*inode) = 0;
#endif
}
if (filp->f_mode & FMODE_READ) {
(inode->u.pipe_i.readers)++;
if(inode->u.pipe_i.writers > 0) {
if(inode->u.pipe_i.readers < 2)
wake_up_interruptible(&(inode->u.pipe_i.wait));
}
else {
if(!(filp->f_flags & O_NONBLOCK) && (inode->i_sb))
while(!(inode->u.pipe_i.writers))
interruptible_sleep_on(&(inode->u.pipe_i.wait));
}
}
if (filp->f_mode & FMODE_WRITE) {
(inode->u.pipe_i.writers)++;
if(inode->u.pipe_i.readers > 0) {
if(inode->u.pipe_i.writers < 2)
wake_up_interruptible(&(inode->u.pipe_i.wait));
}
else {
if(filp->f_flags & O_NONBLOCK)
return -ENXIO;
while(!(inode->u.pipe_i.readers))
interruptible_sleep_on(&(inode->u.pipe_i.wait));
}
}
return 0;
}
