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fs/pipe.c
21.5 KB
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/* * linux/fs/pipe.c * * Copyright (C) 1991, 1992, 1999 Linus Torvalds */ #include <linux/mm.h> #include <linux/file.h> #include <linux/poll.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/mount.h> #include <linux/pipe_fs_i.h> #include <linux/uio.h> #include <linux/highmem.h> |
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#include <linux/pagemap.h> |
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#include <asm/uaccess.h> #include <asm/ioctls.h> /* * We use a start+len construction, which provides full use of the * allocated memory. * -- Florian Coosmann (FGC) * * Reads with count = 0 should always return 0. * -- Julian Bradfield 1999-06-07. * * FIFOs and Pipes now generate SIGIO for both readers and writers. * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 * * pipe_read & write cleanup * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 */ /* Drop the inode semaphore and wait for a pipe event, atomically */ |
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void pipe_wait(struct pipe_inode_info *pipe) |
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{ DEFINE_WAIT(wait); |
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/* * Pipes are system-local resources, so sleeping on them * is considered a noninteractive wait: */ |
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prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE | TASK_NONINTERACTIVE); |
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if (pipe->inode) mutex_unlock(&pipe->inode->i_mutex); |
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schedule(); |
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finish_wait(&pipe->wait, &wait); if (pipe->inode) mutex_lock(&pipe->inode->i_mutex); |
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} |
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static int |
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pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, int atomic) |
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{ unsigned long copy; while (len > 0) { while (!iov->iov_len) iov++; copy = min_t(unsigned long, len, iov->iov_len); |
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if (atomic) { if (__copy_from_user_inatomic(to, iov->iov_base, copy)) return -EFAULT; } else { if (copy_from_user(to, iov->iov_base, copy)) return -EFAULT; } |
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to += copy; len -= copy; iov->iov_base += copy; iov->iov_len -= copy; } return 0; } |
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static int |
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pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, int atomic) |
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{ unsigned long copy; while (len > 0) { while (!iov->iov_len) iov++; copy = min_t(unsigned long, len, iov->iov_len); |
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if (atomic) { if (__copy_to_user_inatomic(iov->iov_base, from, copy)) return -EFAULT; } else { if (copy_to_user(iov->iov_base, from, copy)) return -EFAULT; } |
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from += copy; len -= copy; iov->iov_base += copy; iov->iov_len -= copy; } return 0; } |
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/* * Attempt to pre-fault in the user memory, so we can use atomic copies. * Returns the number of bytes not faulted in. */ static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) { while (!iov->iov_len) iov++; while (len > 0) { unsigned long this_len; this_len = min_t(unsigned long, len, iov->iov_len); if (fault_in_pages_writeable(iov->iov_base, this_len)) break; len -= this_len; iov++; } return len; } /* * Pre-fault in the user memory, so we can use atomic copies. */ static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) { while (!iov->iov_len) iov++; while (len > 0) { unsigned long this_len; this_len = min_t(unsigned long, len, iov->iov_len); fault_in_pages_readable(iov->iov_base, this_len); len -= this_len; iov++; } } |
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static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
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{ struct page *page = buf->page; |
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/* * If nobody else uses this page, and we don't already have a * temporary page, let's keep track of it as a one-deep |
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* allocation cache. (Otherwise just release our reference to it) |
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*/ |
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if (page_count(page) == 1 && !pipe->tmp_page) |
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pipe->tmp_page = page; |
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else page_cache_release(page); |
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} |
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void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
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struct pipe_buffer *buf, int atomic) |
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{ |
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if (atomic) { buf->flags |= PIPE_BUF_FLAG_ATOMIC; return kmap_atomic(buf->page, KM_USER0); } |
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return kmap(buf->page); } |
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void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
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struct pipe_buffer *buf, void *map_data) |
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{ |
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if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; kunmap_atomic(map_data, KM_USER0); } else kunmap(buf->page); |
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} |
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int generic_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
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{ |
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struct page *page = buf->page; if (page_count(page) == 1) { |
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lock_page(page); return 0; } return 1; |
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} |
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void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf) |
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{ page_cache_get(buf->page); } |
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int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf) { return 0; } |
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static struct pipe_buf_operations anon_pipe_buf_ops = { .can_merge = 1, |
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.map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .pin = generic_pipe_buf_pin, |
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.release = anon_pipe_buf_release, |
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.steal = generic_pipe_buf_steal, |
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.get = generic_pipe_buf_get, |
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}; static ssize_t |
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pipe_read(struct kiocb *iocb, const struct iovec *_iov, unsigned long nr_segs, loff_t pos) |
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{ |
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struct file *filp = iocb->ki_filp; |
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struct inode *inode = filp->f_dentry->d_inode; |
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struct pipe_inode_info *pipe; |
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int do_wakeup; ssize_t ret; struct iovec *iov = (struct iovec *)_iov; size_t total_len; total_len = iov_length(iov, nr_segs); /* Null read succeeds. */ if (unlikely(total_len == 0)) return 0; do_wakeup = 0; ret = 0; |
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mutex_lock(&inode->i_mutex); |
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pipe = inode->i_pipe; |
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for (;;) { |
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int bufs = pipe->nrbufs; |
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if (bufs) { |
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int curbuf = pipe->curbuf; struct pipe_buffer *buf = pipe->bufs + curbuf; |
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struct pipe_buf_operations *ops = buf->ops; void *addr; size_t chars = buf->len; |
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int error, atomic; |
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if (chars > total_len) chars = total_len; |
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error = ops->pin(pipe, buf); if (error) { |
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if (!ret) |
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error = ret; |
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break; } |
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|
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atomic = !iov_fault_in_pages_write(iov, chars); redo: addr = ops->map(pipe, buf, atomic); error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); ops->unmap(pipe, buf, addr); |
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if (unlikely(error)) { |
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/* * Just retry with the slow path if we failed. */ if (atomic) { atomic = 0; goto redo; } |
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if (!ret) |
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ret = error; |
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break; } ret += chars; buf->offset += chars; buf->len -= chars; if (!buf->len) { buf->ops = NULL; |
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ops->release(pipe, buf); |
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curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); |
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pipe->curbuf = curbuf; pipe->nrbufs = --bufs; |
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do_wakeup = 1; } total_len -= chars; if (!total_len) break; /* common path: read succeeded */ } if (bufs) /* More to do? */ continue; |
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if (!pipe->writers) |
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break; |
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if (!pipe->waiting_writers) { |
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/* syscall merging: Usually we must not sleep * if O_NONBLOCK is set, or if we got some data. * But if a writer sleeps in kernel space, then * we can wait for that data without violating POSIX. */ if (ret) break; if (filp->f_flags & O_NONBLOCK) { ret = -EAGAIN; break; } } if (signal_pending(current)) { |
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if (!ret) ret = -ERESTARTSYS; |
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break; } if (do_wakeup) { |
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wake_up_interruptible_sync(&pipe->wait); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
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} |
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pipe_wait(pipe); |
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} |
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mutex_unlock(&inode->i_mutex); |
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/* Signal writers asynchronously that there is more room. */ |
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if (do_wakeup) { |
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wake_up_interruptible(&pipe->wait); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
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} if (ret > 0) file_accessed(filp); return ret; } static ssize_t |
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pipe_write(struct kiocb *iocb, const struct iovec *_iov, unsigned long nr_segs, loff_t ppos) |
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{ |
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struct file *filp = iocb->ki_filp; |
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struct inode *inode = filp->f_dentry->d_inode; |
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struct pipe_inode_info *pipe; |
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ssize_t ret; int do_wakeup; struct iovec *iov = (struct iovec *)_iov; size_t total_len; ssize_t chars; total_len = iov_length(iov, nr_segs); /* Null write succeeds. */ if (unlikely(total_len == 0)) return 0; do_wakeup = 0; ret = 0; |
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mutex_lock(&inode->i_mutex); |
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pipe = inode->i_pipe; |
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|
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if (!pipe->readers) { |
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send_sig(SIGPIPE, current, 0); ret = -EPIPE; goto out; } /* We try to merge small writes */ chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ |
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if (pipe->nrbufs && chars != 0) { |
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int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & (PIPE_BUFFERS-1); |
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struct pipe_buffer *buf = pipe->bufs + lastbuf; |
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struct pipe_buf_operations *ops = buf->ops; int offset = buf->offset + buf->len; |
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|
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if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
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int error, atomic = 1; |
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void *addr; |
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|
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error = ops->pin(pipe, buf); if (error) |
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goto out; |
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|
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iov_fault_in_pages_read(iov, chars); redo1: addr = ops->map(pipe, buf, atomic); |
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error = pipe_iov_copy_from_user(offset + addr, iov, |
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chars, atomic); ops->unmap(pipe, buf, addr); |
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ret = error; do_wakeup = 1; |
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if (error) { if (atomic) { atomic = 0; goto redo1; } |
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goto out; |
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} |
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buf->len += chars; total_len -= chars; ret = chars; if (!total_len) goto out; } } for (;;) { int bufs; |
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|
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if (!pipe->readers) { |
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send_sig(SIGPIPE, current, 0); |
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if (!ret) ret = -EPIPE; |
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break; } |
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bufs = pipe->nrbufs; |
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if (bufs < PIPE_BUFFERS) { |
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int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1); struct pipe_buffer *buf = pipe->bufs + newbuf; struct page *page = pipe->tmp_page; |
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char *src; int error, atomic = 1; |
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if (!page) { page = alloc_page(GFP_HIGHUSER); if (unlikely(!page)) { ret = ret ? : -ENOMEM; break; } |
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pipe->tmp_page = page; |
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} |
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/* Always wake up, even if the copy fails. Otherwise |
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* we lock up (O_NONBLOCK-)readers that sleep due to * syscall merging. * FIXME! Is this really true? */ do_wakeup = 1; chars = PAGE_SIZE; if (chars > total_len) chars = total_len; |
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iov_fault_in_pages_read(iov, chars); redo2: if (atomic) src = kmap_atomic(page, KM_USER0); else src = kmap(page); error = pipe_iov_copy_from_user(src, iov, chars, atomic); if (atomic) kunmap_atomic(src, KM_USER0); else kunmap(page); |
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if (unlikely(error)) { |
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if (atomic) { atomic = 0; goto redo2; } |
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if (!ret) |
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ret = error; |
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break; } ret += chars; /* Insert it into the buffer array */ buf->page = page; buf->ops = &anon_pipe_buf_ops; buf->offset = 0; buf->len = chars; |
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pipe->nrbufs = ++bufs; pipe->tmp_page = NULL; |
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total_len -= chars; if (!total_len) break; } if (bufs < PIPE_BUFFERS) continue; if (filp->f_flags & O_NONBLOCK) { |
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if (!ret) ret = -EAGAIN; |
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break; } if (signal_pending(current)) { |
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if (!ret) ret = -ERESTARTSYS; |
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break; } if (do_wakeup) { |
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wake_up_interruptible_sync(&pipe->wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
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do_wakeup = 0; } |
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pipe->waiting_writers++; pipe_wait(pipe); pipe->waiting_writers--; |
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} out: |
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mutex_unlock(&inode->i_mutex); |
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if (do_wakeup) { |
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wake_up_interruptible(&pipe->wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
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} if (ret > 0) |
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file_update_time(filp); |
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return ret; } static ssize_t |
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bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) { return -EBADF; } static ssize_t |
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bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) |
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{ return -EBADF; } static int pipe_ioctl(struct inode *pino, struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = filp->f_dentry->d_inode; |
923f4f239 [PATCH] pipe.c/fi... |
506 |
struct pipe_inode_info *pipe; |
1da177e4c Linux-2.6.12-rc2 |
507 508 509 510 |
int count, buf, nrbufs; switch (cmd) { case FIONREAD: |
9aeedfc47 [PATCH] get rid o... |
511 |
mutex_lock(&inode->i_mutex); |
923f4f239 [PATCH] pipe.c/fi... |
512 |
pipe = inode->i_pipe; |
1da177e4c Linux-2.6.12-rc2 |
513 |
count = 0; |
923f4f239 [PATCH] pipe.c/fi... |
514 515 |
buf = pipe->curbuf; nrbufs = pipe->nrbufs; |
1da177e4c Linux-2.6.12-rc2 |
516 |
while (--nrbufs >= 0) { |
923f4f239 [PATCH] pipe.c/fi... |
517 |
count += pipe->bufs[buf].len; |
1da177e4c Linux-2.6.12-rc2 |
518 519 |
buf = (buf+1) & (PIPE_BUFFERS-1); } |
9aeedfc47 [PATCH] get rid o... |
520 |
mutex_unlock(&inode->i_mutex); |
923f4f239 [PATCH] pipe.c/fi... |
521 |
|
1da177e4c Linux-2.6.12-rc2 |
522 523 524 525 526 527 528 529 530 531 532 533 |
return put_user(count, (int __user *)arg); default: return -EINVAL; } } /* No kernel lock held - fine */ static unsigned int pipe_poll(struct file *filp, poll_table *wait) { unsigned int mask; struct inode *inode = filp->f_dentry->d_inode; |
923f4f239 [PATCH] pipe.c/fi... |
534 |
struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4c Linux-2.6.12-rc2 |
535 |
int nrbufs; |
923f4f239 [PATCH] pipe.c/fi... |
536 |
poll_wait(filp, &pipe->wait, wait); |
1da177e4c Linux-2.6.12-rc2 |
537 538 |
/* Reading only -- no need for acquiring the semaphore. */ |
923f4f239 [PATCH] pipe.c/fi... |
539 |
nrbufs = pipe->nrbufs; |
1da177e4c Linux-2.6.12-rc2 |
540 541 542 |
mask = 0; if (filp->f_mode & FMODE_READ) { mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; |
923f4f239 [PATCH] pipe.c/fi... |
543 |
if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4c Linux-2.6.12-rc2 |
544 545 546 547 548 |
mask |= POLLHUP; } if (filp->f_mode & FMODE_WRITE) { mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; |
5e5d7a222 [PATCH] pipe: rem... |
549 550 551 552 |
/* * Most Unices do not set POLLERR for FIFOs but on Linux they * behave exactly like pipes for poll(). */ |
923f4f239 [PATCH] pipe.c/fi... |
553 |
if (!pipe->readers) |
1da177e4c Linux-2.6.12-rc2 |
554 555 556 557 558 |
mask |= POLLERR; } return mask; } |
1da177e4c Linux-2.6.12-rc2 |
559 560 561 |
static int pipe_release(struct inode *inode, int decr, int decw) { |
923f4f239 [PATCH] pipe.c/fi... |
562 |
struct pipe_inode_info *pipe; |
9aeedfc47 [PATCH] get rid o... |
563 |
mutex_lock(&inode->i_mutex); |
923f4f239 [PATCH] pipe.c/fi... |
564 565 566 |
pipe = inode->i_pipe; pipe->readers -= decr; pipe->writers -= decw; |
341b446bc [PATCH] another r... |
567 |
|
923f4f239 [PATCH] pipe.c/fi... |
568 |
if (!pipe->readers && !pipe->writers) { |
1da177e4c Linux-2.6.12-rc2 |
569 570 |
free_pipe_info(inode); } else { |
923f4f239 [PATCH] pipe.c/fi... |
571 572 573 |
wake_up_interruptible(&pipe->wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4c Linux-2.6.12-rc2 |
574 |
} |
9aeedfc47 [PATCH] get rid o... |
575 |
mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
576 577 578 579 580 581 582 583 584 |
return 0; } static int pipe_read_fasync(int fd, struct file *filp, int on) { struct inode *inode = filp->f_dentry->d_inode; int retval; |
9aeedfc47 [PATCH] get rid o... |
585 586 587 |
mutex_lock(&inode->i_mutex); retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
588 589 590 591 592 593 594 595 596 597 598 599 600 |
if (retval < 0) return retval; return 0; } static int pipe_write_fasync(int fd, struct file *filp, int on) { struct inode *inode = filp->f_dentry->d_inode; int retval; |
9aeedfc47 [PATCH] get rid o... |
601 602 603 |
mutex_lock(&inode->i_mutex); retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
604 605 606 607 608 609 610 611 612 613 614 615 |
if (retval < 0) return retval; return 0; } static int pipe_rdwr_fasync(int fd, struct file *filp, int on) { struct inode *inode = filp->f_dentry->d_inode; |
341b446bc [PATCH] another r... |
616 |
struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4c Linux-2.6.12-rc2 |
617 |
int retval; |
9aeedfc47 [PATCH] get rid o... |
618 |
mutex_lock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
619 |
|
341b446bc [PATCH] another r... |
620 |
retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
1da177e4c Linux-2.6.12-rc2 |
621 622 |
if (retval >= 0) |
341b446bc [PATCH] another r... |
623 |
retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
1da177e4c Linux-2.6.12-rc2 |
624 |
|
9aeedfc47 [PATCH] get rid o... |
625 |
mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 |
if (retval < 0) return retval; return 0; } static int pipe_read_release(struct inode *inode, struct file *filp) { pipe_read_fasync(-1, filp, 0); return pipe_release(inode, 1, 0); } static int pipe_write_release(struct inode *inode, struct file *filp) { pipe_write_fasync(-1, filp, 0); return pipe_release(inode, 0, 1); } static int pipe_rdwr_release(struct inode *inode, struct file *filp) { int decr, decw; pipe_rdwr_fasync(-1, filp, 0); decr = (filp->f_mode & FMODE_READ) != 0; decw = (filp->f_mode & FMODE_WRITE) != 0; return pipe_release(inode, decr, decw); } static int pipe_read_open(struct inode *inode, struct file *filp) { /* We could have perhaps used atomic_t, but this and friends below are the only places. So it doesn't seem worthwhile. */ |
9aeedfc47 [PATCH] get rid o... |
664 665 666 |
mutex_lock(&inode->i_mutex); inode->i_pipe->readers++; mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
667 668 669 670 671 672 673 |
return 0; } static int pipe_write_open(struct inode *inode, struct file *filp) { |
9aeedfc47 [PATCH] get rid o... |
674 675 676 |
mutex_lock(&inode->i_mutex); inode->i_pipe->writers++; mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
677 678 679 680 681 682 683 |
return 0; } static int pipe_rdwr_open(struct inode *inode, struct file *filp) { |
9aeedfc47 [PATCH] get rid o... |
684 |
mutex_lock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
685 |
if (filp->f_mode & FMODE_READ) |
9aeedfc47 [PATCH] get rid o... |
686 |
inode->i_pipe->readers++; |
1da177e4c Linux-2.6.12-rc2 |
687 |
if (filp->f_mode & FMODE_WRITE) |
9aeedfc47 [PATCH] get rid o... |
688 689 |
inode->i_pipe->writers++; mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
690 691 692 693 694 695 696 697 |
return 0; } /* * The file_operations structs are not static because they * are also used in linux/fs/fifo.c to do operations on FIFOs. */ |
4b6f5d20b [PATCH] Make most... |
698 |
const struct file_operations read_fifo_fops = { |
1da177e4c Linux-2.6.12-rc2 |
699 |
.llseek = no_llseek, |
ee0b3e671 [PATCH] Remove re... |
700 701 |
.read = do_sync_read, .aio_read = pipe_read, |
1da177e4c Linux-2.6.12-rc2 |
702 |
.write = bad_pipe_w, |
5e5d7a222 [PATCH] pipe: rem... |
703 |
.poll = pipe_poll, |
1da177e4c Linux-2.6.12-rc2 |
704 705 706 707 708 |
.ioctl = pipe_ioctl, .open = pipe_read_open, .release = pipe_read_release, .fasync = pipe_read_fasync, }; |
4b6f5d20b [PATCH] Make most... |
709 |
const struct file_operations write_fifo_fops = { |
1da177e4c Linux-2.6.12-rc2 |
710 711 |
.llseek = no_llseek, .read = bad_pipe_r, |
ee0b3e671 [PATCH] Remove re... |
712 713 |
.write = do_sync_write, .aio_write = pipe_write, |
5e5d7a222 [PATCH] pipe: rem... |
714 |
.poll = pipe_poll, |
1da177e4c Linux-2.6.12-rc2 |
715 716 717 718 719 |
.ioctl = pipe_ioctl, .open = pipe_write_open, .release = pipe_write_release, .fasync = pipe_write_fasync, }; |
4b6f5d20b [PATCH] Make most... |
720 |
const struct file_operations rdwr_fifo_fops = { |
1da177e4c Linux-2.6.12-rc2 |
721 |
.llseek = no_llseek, |
ee0b3e671 [PATCH] Remove re... |
722 723 724 725 |
.read = do_sync_read, .aio_read = pipe_read, .write = do_sync_write, .aio_write = pipe_write, |
5e5d7a222 [PATCH] pipe: rem... |
726 |
.poll = pipe_poll, |
1da177e4c Linux-2.6.12-rc2 |
727 728 729 730 731 |
.ioctl = pipe_ioctl, .open = pipe_rdwr_open, .release = pipe_rdwr_release, .fasync = pipe_rdwr_fasync, }; |
a19cbd4bf Mark the pipe fil... |
732 |
static struct file_operations read_pipe_fops = { |
1da177e4c Linux-2.6.12-rc2 |
733 |
.llseek = no_llseek, |
ee0b3e671 [PATCH] Remove re... |
734 735 |
.read = do_sync_read, .aio_read = pipe_read, |
1da177e4c Linux-2.6.12-rc2 |
736 737 738 739 740 741 742 |
.write = bad_pipe_w, .poll = pipe_poll, .ioctl = pipe_ioctl, .open = pipe_read_open, .release = pipe_read_release, .fasync = pipe_read_fasync, }; |
a19cbd4bf Mark the pipe fil... |
743 |
static struct file_operations write_pipe_fops = { |
1da177e4c Linux-2.6.12-rc2 |
744 745 |
.llseek = no_llseek, .read = bad_pipe_r, |
ee0b3e671 [PATCH] Remove re... |
746 747 |
.write = do_sync_write, .aio_write = pipe_write, |
1da177e4c Linux-2.6.12-rc2 |
748 749 750 751 752 753 |
.poll = pipe_poll, .ioctl = pipe_ioctl, .open = pipe_write_open, .release = pipe_write_release, .fasync = pipe_write_fasync, }; |
a19cbd4bf Mark the pipe fil... |
754 |
static struct file_operations rdwr_pipe_fops = { |
1da177e4c Linux-2.6.12-rc2 |
755 |
.llseek = no_llseek, |
ee0b3e671 [PATCH] Remove re... |
756 757 758 759 |
.read = do_sync_read, .aio_read = pipe_read, .write = do_sync_write, .aio_write = pipe_write, |
1da177e4c Linux-2.6.12-rc2 |
760 761 762 763 764 765 |
.poll = pipe_poll, .ioctl = pipe_ioctl, .open = pipe_rdwr_open, .release = pipe_rdwr_release, .fasync = pipe_rdwr_fasync, }; |
3a326a2ce [PATCH] introduce... |
766 767 |
struct pipe_inode_info * alloc_pipe_info(struct inode *inode) { |
923f4f239 [PATCH] pipe.c/fi... |
768 |
struct pipe_inode_info *pipe; |
3a326a2ce [PATCH] introduce... |
769 |
|
923f4f239 [PATCH] pipe.c/fi... |
770 771 772 773 774 |
pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); if (pipe) { init_waitqueue_head(&pipe->wait); pipe->r_counter = pipe->w_counter = 1; pipe->inode = inode; |
3a326a2ce [PATCH] introduce... |
775 |
} |
923f4f239 [PATCH] pipe.c/fi... |
776 |
return pipe; |
3a326a2ce [PATCH] introduce... |
777 |
} |
923f4f239 [PATCH] pipe.c/fi... |
778 |
void __free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4c Linux-2.6.12-rc2 |
779 780 |
{ int i; |
1da177e4c Linux-2.6.12-rc2 |
781 |
|
1da177e4c Linux-2.6.12-rc2 |
782 |
for (i = 0; i < PIPE_BUFFERS; i++) { |
923f4f239 [PATCH] pipe.c/fi... |
783 |
struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4c Linux-2.6.12-rc2 |
784 |
if (buf->ops) |
923f4f239 [PATCH] pipe.c/fi... |
785 |
buf->ops->release(pipe, buf); |
1da177e4c Linux-2.6.12-rc2 |
786 |
} |
923f4f239 [PATCH] pipe.c/fi... |
787 788 789 |
if (pipe->tmp_page) __free_page(pipe->tmp_page); kfree(pipe); |
1da177e4c Linux-2.6.12-rc2 |
790 |
} |
b92ce5589 [PATCH] splice: a... |
791 792 793 794 795 |
void free_pipe_info(struct inode *inode) { __free_pipe_info(inode->i_pipe); inode->i_pipe = NULL; } |
fa3536cc1 [PATCH] Use __rea... |
796 |
static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4c Linux-2.6.12-rc2 |
797 798 799 800 |
static int pipefs_delete_dentry(struct dentry *dentry) { return 1; } |
341b446bc [PATCH] another r... |
801 |
|
1da177e4c Linux-2.6.12-rc2 |
802 803 804 805 806 807 808 |
static struct dentry_operations pipefs_dentry_operations = { .d_delete = pipefs_delete_dentry, }; static struct inode * get_pipe_inode(void) { struct inode *inode = new_inode(pipe_mnt->mnt_sb); |
923f4f239 [PATCH] pipe.c/fi... |
809 |
struct pipe_inode_info *pipe; |
1da177e4c Linux-2.6.12-rc2 |
810 811 812 |
if (!inode) goto fail_inode; |
923f4f239 [PATCH] pipe.c/fi... |
813 814 |
pipe = alloc_pipe_info(inode); if (!pipe) |
1da177e4c Linux-2.6.12-rc2 |
815 |
goto fail_iput; |
923f4f239 [PATCH] pipe.c/fi... |
816 |
inode->i_pipe = pipe; |
3a326a2ce [PATCH] introduce... |
817 |
|
923f4f239 [PATCH] pipe.c/fi... |
818 |
pipe->readers = pipe->writers = 1; |
1da177e4c Linux-2.6.12-rc2 |
819 820 821 822 823 824 825 826 827 828 829 830 831 |
inode->i_fop = &rdwr_pipe_fops; /* * Mark the inode dirty from the very beginning, * that way it will never be moved to the dirty * list because "mark_inode_dirty()" will think * that it already _is_ on the dirty list. */ inode->i_state = I_DIRTY; inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; inode->i_uid = current->fsuid; inode->i_gid = current->fsgid; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
923f4f239 [PATCH] pipe.c/fi... |
832 |
|
1da177e4c Linux-2.6.12-rc2 |
833 834 835 836 |
return inode; fail_iput: iput(inode); |
341b446bc [PATCH] another r... |
837 |
|
1da177e4c Linux-2.6.12-rc2 |
838 839 840 |
fail_inode: return NULL; } |
d6cbd281d [PATCH] Some clea... |
841 |
struct file *create_write_pipe(void) |
1da177e4c Linux-2.6.12-rc2 |
842 |
{ |
d6cbd281d [PATCH] Some clea... |
843 844 845 |
int err; struct inode *inode; struct file *f; |
1da177e4c Linux-2.6.12-rc2 |
846 |
struct dentry *dentry; |
d6cbd281d [PATCH] Some clea... |
847 848 |
char name[32]; struct qstr this; |
1da177e4c Linux-2.6.12-rc2 |
849 |
|
d6cbd281d [PATCH] Some clea... |
850 851 852 853 |
f = get_empty_filp(); if (!f) return ERR_PTR(-ENFILE); err = -ENFILE; |
1da177e4c Linux-2.6.12-rc2 |
854 855 |
inode = get_pipe_inode(); if (!inode) |
d6cbd281d [PATCH] Some clea... |
856 |
goto err_file; |
1da177e4c Linux-2.6.12-rc2 |
857 |
|
1da177e4c Linux-2.6.12-rc2 |
858 859 860 861 |
sprintf(name, "[%lu]", inode->i_ino); this.name = name; this.len = strlen(name); this.hash = inode->i_ino; /* will go */ |
d6cbd281d [PATCH] Some clea... |
862 |
err = -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
863 864 |
dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); if (!dentry) |
d6cbd281d [PATCH] Some clea... |
865 |
goto err_inode; |
341b446bc [PATCH] another r... |
866 |
|
1da177e4c Linux-2.6.12-rc2 |
867 868 |
dentry->d_op = &pipefs_dentry_operations; d_add(dentry, inode); |
d6cbd281d [PATCH] Some clea... |
869 870 871 |
f->f_vfsmnt = mntget(pipe_mnt); f->f_dentry = dentry; f->f_mapping = inode->i_mapping; |
341b446bc [PATCH] another r... |
872 |
|
d6cbd281d [PATCH] Some clea... |
873 874 875 876 877 878 |
f->f_flags = O_WRONLY; f->f_op = &write_pipe_fops; f->f_mode = FMODE_WRITE; f->f_version = 0; return f; |
1da177e4c Linux-2.6.12-rc2 |
879 |
|
d6cbd281d [PATCH] Some clea... |
880 |
err_inode: |
1da177e4c Linux-2.6.12-rc2 |
881 882 |
free_pipe_info(inode); iput(inode); |
d6cbd281d [PATCH] Some clea... |
883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 |
err_file: put_filp(f); return ERR_PTR(err); } void free_write_pipe(struct file *f) { mntput(f->f_vfsmnt); dput(f->f_dentry); put_filp(f); } struct file *create_read_pipe(struct file *wrf) { struct file *f = get_empty_filp(); if (!f) return ERR_PTR(-ENFILE); /* Grab pipe from the writer */ f->f_vfsmnt = mntget(wrf->f_vfsmnt); f->f_dentry = dget(wrf->f_dentry); f->f_mapping = wrf->f_dentry->d_inode->i_mapping; f->f_pos = 0; f->f_flags = O_RDONLY; f->f_op = &read_pipe_fops; f->f_mode = FMODE_READ; f->f_version = 0; return f; } int do_pipe(int *fd) { struct file *fw, *fr; int error; int fdw, fdr; fw = create_write_pipe(); if (IS_ERR(fw)) return PTR_ERR(fw); fr = create_read_pipe(fw); error = PTR_ERR(fr); if (IS_ERR(fr)) goto err_write_pipe; error = get_unused_fd(); if (error < 0) goto err_read_pipe; fdr = error; error = get_unused_fd(); if (error < 0) goto err_fdr; fdw = error; fd_install(fdr, fr); fd_install(fdw, fw); fd[0] = fdr; fd[1] = fdw; return 0; err_fdr: put_unused_fd(fdr); err_read_pipe: put_filp(fr); err_write_pipe: free_write_pipe(fw); return error; |
1da177e4c Linux-2.6.12-rc2 |
953 954 955 956 957 958 959 960 |
} /* * pipefs should _never_ be mounted by userland - too much of security hassle, * no real gain from having the whole whorehouse mounted. So we don't need * any operations on the root directory. However, we need a non-trivial * d_name - pipe: will go nicely and kill the special-casing in procfs. */ |
454e2398b [PATCH] VFS: Perm... |
961 962 963 |
static int pipefs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) |
1da177e4c Linux-2.6.12-rc2 |
964 |
{ |
454e2398b [PATCH] VFS: Perm... |
965 |
return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt); |
1da177e4c Linux-2.6.12-rc2 |
966 967 968 969 970 971 972 973 974 975 976 |
} static struct file_system_type pipe_fs_type = { .name = "pipefs", .get_sb = pipefs_get_sb, .kill_sb = kill_anon_super, }; static int __init init_pipe_fs(void) { int err = register_filesystem(&pipe_fs_type); |
341b446bc [PATCH] another r... |
977 |
|
1da177e4c Linux-2.6.12-rc2 |
978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 |
if (!err) { pipe_mnt = kern_mount(&pipe_fs_type); if (IS_ERR(pipe_mnt)) { err = PTR_ERR(pipe_mnt); unregister_filesystem(&pipe_fs_type); } } return err; } static void __exit exit_pipe_fs(void) { unregister_filesystem(&pipe_fs_type); mntput(pipe_mnt); } fs_initcall(init_pipe_fs); module_exit(exit_pipe_fs); |