diff options
Diffstat (limited to 'fs/fifo.c')
-rw-r--r-- | fs/fifo.c | 153 |
1 files changed, 0 insertions, 153 deletions
diff --git a/fs/fifo.c b/fs/fifo.c deleted file mode 100644 index cf6f434..0000000 --- a/fs/fifo.c +++ /dev/null @@ -1,153 +0,0 @@ -/* - * linux/fs/fifo.c - * - * written by Paul H. Hargrove - * - * Fixes: - * 10-06-1999, AV: fixed OOM handling in fifo_open(), moved - * initialization there, switched to external - * allocation of pipe_inode_info. - */ - -#include <linux/mm.h> -#include <linux/fs.h> -#include <linux/sched.h> -#include <linux/pipe_fs_i.h> - -static int wait_for_partner(struct inode* inode, unsigned int *cnt) -{ - int cur = *cnt; - - while (cur == *cnt) { - pipe_wait(inode->i_pipe); - if (signal_pending(current)) - break; - } - return cur == *cnt ? -ERESTARTSYS : 0; -} - -static void wake_up_partner(struct inode* inode) -{ - wake_up_interruptible(&inode->i_pipe->wait); -} - -static int fifo_open(struct inode *inode, struct file *filp) -{ - struct pipe_inode_info *pipe; - int ret; - - mutex_lock(&inode->i_mutex); - pipe = inode->i_pipe; - if (!pipe) { - ret = -ENOMEM; - pipe = alloc_pipe_info(inode); - if (!pipe) - goto err_nocleanup; - inode->i_pipe = pipe; - } - filp->f_version = 0; - - /* We can only do regular read/write on fifos */ - filp->f_mode &= (FMODE_READ | FMODE_WRITE); - - switch (filp->f_mode) { - case FMODE_READ: - /* - * O_RDONLY - * POSIX.1 says that O_NONBLOCK means return with the FIFO - * opened, even when there is no process writing the FIFO. - */ - filp->f_op = &read_pipefifo_fops; - pipe->r_counter++; - if (pipe->readers++ == 0) - wake_up_partner(inode); - - if (!pipe->writers) { - if ((filp->f_flags & O_NONBLOCK)) { - /* suppress POLLHUP until we have - * seen a writer */ - filp->f_version = pipe->w_counter; - } else { - if (wait_for_partner(inode, &pipe->w_counter)) - goto err_rd; - } - } - break; - - case FMODE_WRITE: - /* - * O_WRONLY - * POSIX.1 says that O_NONBLOCK means return -1 with - * errno=ENXIO when there is no process reading the FIFO. - */ - ret = -ENXIO; - if ((filp->f_flags & O_NONBLOCK) && !pipe->readers) - goto err; - - filp->f_op = &write_pipefifo_fops; - pipe->w_counter++; - if (!pipe->writers++) - wake_up_partner(inode); - - if (!pipe->readers) { - if (wait_for_partner(inode, &pipe->r_counter)) - goto err_wr; - } - break; - - case FMODE_READ | FMODE_WRITE: - /* - * O_RDWR - * POSIX.1 leaves this case "undefined" when O_NONBLOCK is set. - * This implementation will NEVER block on a O_RDWR open, since - * the process can at least talk to itself. - */ - filp->f_op = &rdwr_pipefifo_fops; - - pipe->readers++; - pipe->writers++; - pipe->r_counter++; - pipe->w_counter++; - if (pipe->readers == 1 || pipe->writers == 1) - wake_up_partner(inode); - break; - - default: - ret = -EINVAL; - goto err; - } - - /* Ok! */ - mutex_unlock(&inode->i_mutex); - return 0; - -err_rd: - if (!--pipe->readers) - wake_up_interruptible(&pipe->wait); - ret = -ERESTARTSYS; - goto err; - -err_wr: - if (!--pipe->writers) - wake_up_interruptible(&pipe->wait); - ret = -ERESTARTSYS; - goto err; - -err: - if (!pipe->readers && !pipe->writers) - free_pipe_info(inode); - -err_nocleanup: - mutex_unlock(&inode->i_mutex); - return ret; -} - -/* - * Dummy default file-operations: the only thing this does - * is contain the open that then fills in the correct operations - * depending on the access mode of the file... - */ -const struct file_operations def_fifo_fops = { - .open = fifo_open, /* will set read_ or write_pipefifo_fops */ - .llseek = noop_llseek, -}; |