Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * linux/fs/pipe.c |
| 4 | * |
| 5 | * Copyright (C) 1991, 1992, 1999 Linus Torvalds |
| 6 | */ |
| 7 | |
| 8 | #include <linux/mm.h> |
| 9 | #include <linux/file.h> |
| 10 | #include <linux/poll.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/fs.h> |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 15 | #include <linux/log2.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/mount.h> |
David Howells | 4fa7ec5 | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 17 | #include <linux/pseudo_fs.h> |
Muthu Kumar | b502bd1 | 2012-03-23 15:01:50 -0700 | [diff] [blame] | 18 | #include <linux/magic.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/pipe_fs_i.h> |
| 20 | #include <linux/uio.h> |
| 21 | #include <linux/highmem.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 22 | #include <linux/pagemap.h> |
Al Viro | db34950 | 2007-02-07 01:48:00 -0500 | [diff] [blame] | 23 | #include <linux/audit.h> |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 24 | #include <linux/syscalls.h> |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 25 | #include <linux/fcntl.h> |
Vladimir Davydov | d86133b | 2016-07-26 15:24:33 -0700 | [diff] [blame] | 26 | #include <linux/memcontrol.h> |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 27 | #include <linux/watch_queue.h> |
Luis Chamberlain | 1998f19 | 2022-01-21 22:13:20 -0800 | [diff] [blame] | 28 | #include <linux/sysctl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 30 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <asm/ioctls.h> |
| 32 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 33 | #include "internal.h" |
| 34 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | /* |
Alex Xu (Hello71) | 46c4c9d | 2021-08-05 10:40:47 -0400 | [diff] [blame] | 36 | * New pipe buffers will be restricted to this size while the user is exceeding |
| 37 | * their pipe buffer quota. The general pipe use case needs at least two |
| 38 | * buffers: one for data yet to be read, and one for new data. If this is less |
| 39 | * than two, then a write to a non-empty pipe may block even if the pipe is not |
| 40 | * full. This can occur with GNU make jobserver or similar uses of pipes as |
| 41 | * semaphores: multiple processes may be waiting to write tokens back to the |
| 42 | * pipe before reading tokens: https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/. |
| 43 | * |
| 44 | * Users can reduce their pipe buffers with F_SETPIPE_SZ below this at their |
| 45 | * own risk, namely: pipe writes to non-full pipes may block until the pipe is |
| 46 | * emptied. |
| 47 | */ |
| 48 | #define PIPE_MIN_DEF_BUFFERS 2 |
| 49 | |
| 50 | /* |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 51 | * The max size that a non-root user is allowed to grow the pipe. Can |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 52 | * be set by root in /proc/sys/fs/pipe-max-size |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 53 | */ |
Luis Chamberlain | 1998f19 | 2022-01-21 22:13:20 -0800 | [diff] [blame] | 54 | static unsigned int pipe_max_size = 1048576; |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 55 | |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 56 | /* Maximum allocatable pages per user. Hard limit is unset by default, soft |
| 57 | * matches default values. |
| 58 | */ |
Luis Chamberlain | 1998f19 | 2022-01-21 22:13:20 -0800 | [diff] [blame] | 59 | static unsigned long pipe_user_pages_hard; |
| 60 | static unsigned long pipe_user_pages_soft = PIPE_DEF_BUFFERS * INR_OPEN_CUR; |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 61 | |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 62 | /* |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 63 | * We use head and tail indices that aren't masked off, except at the point of |
| 64 | * dereference, but rather they're allowed to wrap naturally. This means there |
| 65 | * isn't a dead spot in the buffer, but the ring has to be a power of two and |
| 66 | * <= 2^31. |
| 67 | * -- David Howells 2019-09-23. |
| 68 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | * Reads with count = 0 should always return 0. |
| 70 | * -- Julian Bradfield 1999-06-07. |
| 71 | * |
| 72 | * FIFOs and Pipes now generate SIGIO for both readers and writers. |
| 73 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 |
| 74 | * |
| 75 | * pipe_read & write cleanup |
| 76 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 |
| 77 | */ |
| 78 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 79 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
| 80 | { |
Al Viro | 6447a3c | 2013-03-21 11:01:38 -0400 | [diff] [blame] | 81 | if (pipe->files) |
Al Viro | 72b0d9a | 2013-03-21 02:32:24 -0400 | [diff] [blame] | 82 | mutex_lock_nested(&pipe->mutex, subclass); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | void pipe_lock(struct pipe_inode_info *pipe) |
| 86 | { |
| 87 | /* |
| 88 | * pipe_lock() nests non-pipe inode locks (for writing to a file) |
| 89 | */ |
| 90 | pipe_lock_nested(pipe, I_MUTEX_PARENT); |
| 91 | } |
| 92 | EXPORT_SYMBOL(pipe_lock); |
| 93 | |
| 94 | void pipe_unlock(struct pipe_inode_info *pipe) |
| 95 | { |
Al Viro | 6447a3c | 2013-03-21 11:01:38 -0400 | [diff] [blame] | 96 | if (pipe->files) |
Al Viro | 72b0d9a | 2013-03-21 02:32:24 -0400 | [diff] [blame] | 97 | mutex_unlock(&pipe->mutex); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 98 | } |
| 99 | EXPORT_SYMBOL(pipe_unlock); |
| 100 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 101 | static inline void __pipe_lock(struct pipe_inode_info *pipe) |
| 102 | { |
| 103 | mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT); |
| 104 | } |
| 105 | |
| 106 | static inline void __pipe_unlock(struct pipe_inode_info *pipe) |
| 107 | { |
| 108 | mutex_unlock(&pipe->mutex); |
| 109 | } |
| 110 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 111 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
| 112 | struct pipe_inode_info *pipe2) |
| 113 | { |
| 114 | BUG_ON(pipe1 == pipe2); |
| 115 | |
| 116 | if (pipe1 < pipe2) { |
| 117 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); |
| 118 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); |
| 119 | } else { |
Peter Zijlstra | 023d43c | 2009-07-21 10:09:23 +0200 | [diff] [blame] | 120 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
| 121 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 122 | } |
| 123 | } |
| 124 | |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 125 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
| 126 | struct pipe_buffer *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | { |
| 128 | struct page *page = buf->page; |
| 129 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 130 | /* |
| 131 | * If nobody else uses this page, and we don't already have a |
| 132 | * temporary page, let's keep track of it as a one-deep |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 133 | * allocation cache. (Otherwise just release our reference to it) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 134 | */ |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 135 | if (page_count(page) == 1 && !pipe->tmp_page) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 136 | pipe->tmp_page = page; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 137 | else |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 138 | put_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | } |
| 140 | |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 141 | static bool anon_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 142 | struct pipe_buffer *buf) |
Vladimir Davydov | d86133b | 2016-07-26 15:24:33 -0700 | [diff] [blame] | 143 | { |
| 144 | struct page *page = buf->page; |
| 145 | |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 146 | if (page_count(page) != 1) |
| 147 | return false; |
| 148 | memcg_kmem_uncharge_page(page, 0); |
| 149 | __SetPageLocked(page); |
| 150 | return true; |
Vladimir Davydov | d86133b | 2016-07-26 15:24:33 -0700 | [diff] [blame] | 151 | } |
| 152 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 153 | /** |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 154 | * generic_pipe_buf_try_steal - attempt to take ownership of a &pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 155 | * @pipe: the pipe that the buffer belongs to |
| 156 | * @buf: the buffer to attempt to steal |
| 157 | * |
| 158 | * Description: |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 159 | * This function attempts to steal the &struct page attached to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 160 | * @buf. If successful, this function returns 0 and returns with |
| 161 | * the page locked. The caller may then reuse the page for whatever |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 162 | * he wishes; the typical use is insertion into a different file |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 163 | * page cache. |
| 164 | */ |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 165 | bool generic_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 166 | struct pipe_buffer *buf) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 167 | { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 168 | struct page *page = buf->page; |
| 169 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 170 | /* |
| 171 | * A reference of one is golden, that means that the owner of this |
| 172 | * page is the only one holding a reference to it. lock the page |
| 173 | * and return OK. |
| 174 | */ |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 175 | if (page_count(page) == 1) { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 176 | lock_page(page); |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 177 | return true; |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 178 | } |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 179 | return false; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 180 | } |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 181 | EXPORT_SYMBOL(generic_pipe_buf_try_steal); |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 182 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 183 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 184 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 185 | * @pipe: the pipe that the buffer belongs to |
| 186 | * @buf: the buffer to get a reference to |
| 187 | * |
| 188 | * Description: |
| 189 | * This function grabs an extra reference to @buf. It's used in |
Randy Dunlap | 3d742d4 | 2021-02-24 12:00:48 -0800 | [diff] [blame] | 190 | * the tee() system call, when we duplicate the buffers in one |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 191 | * pipe into another. |
| 192 | */ |
Matthew Wilcox | 15fab63 | 2019-04-05 14:02:10 -0700 | [diff] [blame] | 193 | bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 194 | { |
Linus Torvalds | cd1adf1 | 2021-09-07 11:03:45 -0700 | [diff] [blame] | 195 | return try_get_page(buf->page); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 196 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 197 | EXPORT_SYMBOL(generic_pipe_buf_get); |
Jens Axboe | 7052449 | 2006-04-11 15:51:17 +0200 | [diff] [blame] | 198 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 199 | /** |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 200 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer |
| 201 | * @pipe: the pipe that the buffer belongs to |
| 202 | * @buf: the buffer to put a reference to |
| 203 | * |
| 204 | * Description: |
| 205 | * This function releases a reference to @buf. |
| 206 | */ |
| 207 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, |
| 208 | struct pipe_buffer *buf) |
| 209 | { |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 210 | put_page(buf->page); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 211 | } |
Miklos Szeredi | 51921cb | 2010-05-26 08:44:22 +0200 | [diff] [blame] | 212 | EXPORT_SYMBOL(generic_pipe_buf_release); |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 213 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 214 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
Christoph Hellwig | c928f64 | 2020-05-20 17:58:16 +0200 | [diff] [blame] | 215 | .release = anon_pipe_buf_release, |
| 216 | .try_steal = anon_pipe_buf_try_steal, |
| 217 | .get = generic_pipe_buf_get, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | }; |
| 219 | |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 220 | /* Done while waiting without holding the pipe lock - thus the READ_ONCE() */ |
| 221 | static inline bool pipe_readable(const struct pipe_inode_info *pipe) |
| 222 | { |
| 223 | unsigned int head = READ_ONCE(pipe->head); |
| 224 | unsigned int tail = READ_ONCE(pipe->tail); |
| 225 | unsigned int writers = READ_ONCE(pipe->writers); |
| 226 | |
| 227 | return !pipe_empty(head, tail) || !writers; |
| 228 | } |
| 229 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | static ssize_t |
Al Viro | fb9096a | 2014-04-02 19:56:54 -0400 | [diff] [blame] | 231 | pipe_read(struct kiocb *iocb, struct iov_iter *to) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | { |
Al Viro | fb9096a | 2014-04-02 19:56:54 -0400 | [diff] [blame] | 233 | size_t total_len = iov_iter_count(to); |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 234 | struct file *filp = iocb->ki_filp; |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 235 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 236 | bool was_full, wake_next_reader = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | /* Null read succeeds. */ |
| 240 | if (unlikely(total_len == 0)) |
| 241 | return 0; |
| 242 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | ret = 0; |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 244 | __pipe_lock(pipe); |
Linus Torvalds | f467a6a | 2019-12-07 12:54:26 -0800 | [diff] [blame] | 245 | |
| 246 | /* |
| 247 | * We only wake up writers if the pipe was full when we started |
| 248 | * reading in order to avoid unnecessary wakeups. |
| 249 | * |
| 250 | * But when we do wake up writers, we do so using a sync wakeup |
| 251 | * (WF_SYNC), because we want them to get going and generate more |
| 252 | * data for us. |
| 253 | */ |
| 254 | was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | for (;;) { |
David Howells | 2ed147f | 2022-03-11 13:24:36 +0000 | [diff] [blame] | 256 | /* Read ->head with a barrier vs post_one_notification() */ |
| 257 | unsigned int head = smp_load_acquire(&pipe->head); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 258 | unsigned int tail = pipe->tail; |
| 259 | unsigned int mask = pipe->ring_size - 1; |
| 260 | |
David Howells | e7d553d | 2020-01-14 17:07:12 +0000 | [diff] [blame] | 261 | #ifdef CONFIG_WATCH_QUEUE |
| 262 | if (pipe->note_loss) { |
| 263 | struct watch_notification n; |
| 264 | |
| 265 | if (total_len < 8) { |
| 266 | if (ret == 0) |
| 267 | ret = -ENOBUFS; |
| 268 | break; |
| 269 | } |
| 270 | |
| 271 | n.type = WATCH_TYPE_META; |
| 272 | n.subtype = WATCH_META_LOSS_NOTIFICATION; |
| 273 | n.info = watch_sizeof(n); |
| 274 | if (copy_to_iter(&n, sizeof(n), to) != sizeof(n)) { |
| 275 | if (ret == 0) |
| 276 | ret = -EFAULT; |
| 277 | break; |
| 278 | } |
| 279 | ret += sizeof(n); |
| 280 | total_len -= sizeof(n); |
| 281 | pipe->note_loss = false; |
| 282 | } |
| 283 | #endif |
| 284 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 285 | if (!pipe_empty(head, tail)) { |
| 286 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | size_t chars = buf->len; |
Al Viro | 637b58c | 2014-02-03 19:11:42 -0500 | [diff] [blame] | 288 | size_t written; |
| 289 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | |
David Howells | 8cfba76 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 291 | if (chars > total_len) { |
| 292 | if (buf->flags & PIPE_BUF_FLAG_WHOLE) { |
| 293 | if (ret == 0) |
| 294 | ret = -ENOBUFS; |
| 295 | break; |
| 296 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | chars = total_len; |
David Howells | 8cfba76 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 298 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | |
Miklos Szeredi | fba597d | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 300 | error = pipe_buf_confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 301 | if (error) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 302 | if (!ret) |
Nicolas Kaiser | e5953cb | 2010-10-21 14:56:00 +0200 | [diff] [blame] | 303 | ret = error; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 304 | break; |
| 305 | } |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 306 | |
Al Viro | fb9096a | 2014-04-02 19:56:54 -0400 | [diff] [blame] | 307 | written = copy_page_to_iter(buf->page, buf->offset, chars, to); |
Al Viro | 637b58c | 2014-02-03 19:11:42 -0500 | [diff] [blame] | 308 | if (unlikely(written < chars)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 309 | if (!ret) |
Al Viro | 637b58c | 2014-02-03 19:11:42 -0500 | [diff] [blame] | 310 | ret = -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | break; |
| 312 | } |
| 313 | ret += chars; |
| 314 | buf->offset += chars; |
| 315 | buf->len -= chars; |
Linus Torvalds | 9883035a | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 316 | |
| 317 | /* Was it a packet buffer? Clean up and exit */ |
| 318 | if (buf->flags & PIPE_BUF_FLAG_PACKET) { |
| 319 | total_len = chars; |
| 320 | buf->len = 0; |
| 321 | } |
| 322 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | if (!buf->len) { |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 324 | pipe_buf_release(pipe, buf); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 325 | spin_lock_irq(&pipe->rd_wait.lock); |
David Howells | e7d553d | 2020-01-14 17:07:12 +0000 | [diff] [blame] | 326 | #ifdef CONFIG_WATCH_QUEUE |
| 327 | if (buf->flags & PIPE_BUF_FLAG_LOSS) |
| 328 | pipe->note_loss = true; |
| 329 | #endif |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 330 | tail++; |
| 331 | pipe->tail = tail; |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 332 | spin_unlock_irq(&pipe->rd_wait.lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | } |
| 334 | total_len -= chars; |
| 335 | if (!total_len) |
| 336 | break; /* common path: read succeeded */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 337 | if (!pipe_empty(head, tail)) /* More to do? */ |
| 338 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | } |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 340 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 341 | if (!pipe->writers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | break; |
Linus Torvalds | a28c8b9 | 2019-12-07 13:21:01 -0800 | [diff] [blame] | 343 | if (ret) |
| 344 | break; |
| 345 | if (filp->f_flags & O_NONBLOCK) { |
| 346 | ret = -EAGAIN; |
| 347 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | } |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 349 | __pipe_unlock(pipe); |
Linus Torvalds | d1c6a2a | 2019-12-11 11:46:19 -0800 | [diff] [blame] | 350 | |
| 351 | /* |
| 352 | * We only get here if we didn't actually read anything. |
| 353 | * |
| 354 | * However, we could have seen (and removed) a zero-sized |
| 355 | * pipe buffer, and might have made space in the buffers |
| 356 | * that way. |
| 357 | * |
| 358 | * You can't make zero-sized pipe buffers by doing an empty |
| 359 | * write (not even in packet mode), but they can happen if |
| 360 | * the writer gets an EFAULT when trying to fill a buffer |
| 361 | * that already got allocated and inserted in the buffer |
| 362 | * array. |
| 363 | * |
| 364 | * So we still need to wake up any pending writers in the |
| 365 | * _very_ unlikely case that the pipe was full, but we got |
| 366 | * no data. |
| 367 | */ |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 368 | if (unlikely(was_full)) |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 369 | wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 370 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | d1c6a2a | 2019-12-11 11:46:19 -0800 | [diff] [blame] | 371 | |
| 372 | /* |
| 373 | * But because we didn't read anything, at this point we can |
| 374 | * just return directly with -ERESTARTSYS if we're interrupted, |
| 375 | * since we've done any required wakeups and there's no need |
| 376 | * to mark anything accessed. And we've dropped the lock. |
| 377 | */ |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 378 | if (wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)) < 0) |
Linus Torvalds | d1c6a2a | 2019-12-11 11:46:19 -0800 | [diff] [blame] | 379 | return -ERESTARTSYS; |
| 380 | |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 381 | __pipe_lock(pipe); |
Linus Torvalds | f467a6a | 2019-12-07 12:54:26 -0800 | [diff] [blame] | 382 | was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 383 | wake_next_reader = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 385 | if (pipe_empty(pipe->head, pipe->tail)) |
| 386 | wake_next_reader = false; |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 387 | __pipe_unlock(pipe); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 388 | |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 389 | if (was_full) |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 390 | wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 391 | if (wake_next_reader) |
| 392 | wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 393 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | if (ret > 0) |
| 395 | file_accessed(filp); |
| 396 | return ret; |
| 397 | } |
| 398 | |
Linus Torvalds | 9883035a | 2012-04-29 13:12:42 -0700 | [diff] [blame] | 399 | static inline int is_packetized(struct file *file) |
| 400 | { |
| 401 | return (file->f_flags & O_DIRECT) != 0; |
| 402 | } |
| 403 | |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 404 | /* Done while waiting without holding the pipe lock - thus the READ_ONCE() */ |
| 405 | static inline bool pipe_writable(const struct pipe_inode_info *pipe) |
| 406 | { |
| 407 | unsigned int head = READ_ONCE(pipe->head); |
| 408 | unsigned int tail = READ_ONCE(pipe->tail); |
| 409 | unsigned int max_usage = READ_ONCE(pipe->max_usage); |
| 410 | |
| 411 | return !pipe_full(head, tail, max_usage) || |
| 412 | !READ_ONCE(pipe->readers); |
| 413 | } |
| 414 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | static ssize_t |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 416 | pipe_write(struct kiocb *iocb, struct iov_iter *from) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 418 | struct file *filp = iocb->ki_filp; |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 419 | struct pipe_inode_info *pipe = filp->private_data; |
David Howells | 8f868d6 | 2019-12-05 22:30:37 +0000 | [diff] [blame] | 420 | unsigned int head; |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 421 | ssize_t ret = 0; |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 422 | size_t total_len = iov_iter_count(from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | ssize_t chars; |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 424 | bool was_empty = false; |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 425 | bool wake_next_writer = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | /* Null write succeeds. */ |
| 428 | if (unlikely(total_len == 0)) |
| 429 | return 0; |
| 430 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 431 | __pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 433 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | send_sig(SIGPIPE, current, 0); |
| 435 | ret = -EPIPE; |
| 436 | goto out; |
| 437 | } |
| 438 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 439 | #ifdef CONFIG_WATCH_QUEUE |
| 440 | if (pipe->watch_queue) { |
| 441 | ret = -EXDEV; |
| 442 | goto out; |
| 443 | } |
| 444 | #endif |
| 445 | |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 446 | /* |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 447 | * If it wasn't empty we try to merge new data into |
| 448 | * the last buffer. |
| 449 | * |
| 450 | * That naturally merges small writes, but it also |
Linus Torvalds | 3a34b13 | 2021-07-30 15:42:34 -0700 | [diff] [blame] | 451 | * page-aligns the rest of the writes for large writes |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 452 | * spanning multiple pages. |
| 453 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 454 | head = pipe->head; |
Linus Torvalds | 3b84482 | 2021-08-05 10:04:43 -0700 | [diff] [blame] | 455 | was_empty = pipe_empty(head, pipe->tail); |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 456 | chars = total_len & (PAGE_SIZE-1); |
Linus Torvalds | 3b84482 | 2021-08-05 10:04:43 -0700 | [diff] [blame] | 457 | if (chars && !was_empty) { |
David Howells | 8f868d6 | 2019-12-05 22:30:37 +0000 | [diff] [blame] | 458 | unsigned int mask = pipe->ring_size - 1; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 459 | struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | int offset = buf->offset + buf->len; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 461 | |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 462 | if ((buf->flags & PIPE_BUF_FLAG_CAN_MERGE) && |
| 463 | offset + chars <= PAGE_SIZE) { |
Miklos Szeredi | fba597d | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 464 | ret = pipe_buf_confirm(pipe, buf); |
Eric Biggers | 6ae0806 | 2015-10-17 16:26:09 -0500 | [diff] [blame] | 465 | if (ret) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 466 | goto out; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 467 | |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 468 | ret = copy_page_from_iter(buf->page, offset, chars, from); |
| 469 | if (unlikely(ret < chars)) { |
Eric Biggers | 6ae0806 | 2015-10-17 16:26:09 -0500 | [diff] [blame] | 470 | ret = -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | goto out; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 472 | } |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 473 | |
Eric Biggers | 6ae0806 | 2015-10-17 16:26:09 -0500 | [diff] [blame] | 474 | buf->len += ret; |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 475 | if (!iov_iter_count(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | goto out; |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | for (;;) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 481 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | send_sig(SIGPIPE, current, 0); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 483 | if (!ret) |
| 484 | ret = -EPIPE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | break; |
| 486 | } |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 487 | |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 488 | head = pipe->head; |
David Howells | 8f868d6 | 2019-12-05 22:30:37 +0000 | [diff] [blame] | 489 | if (!pipe_full(head, pipe->tail, pipe->max_usage)) { |
| 490 | unsigned int mask = pipe->ring_size - 1; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 491 | struct pipe_buffer *buf = &pipe->bufs[head & mask]; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 492 | struct page *page = pipe->tmp_page; |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 493 | int copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | |
| 495 | if (!page) { |
Vladimir Davydov | d86133b | 2016-07-26 15:24:33 -0700 | [diff] [blame] | 496 | page = alloc_page(GFP_HIGHUSER | __GFP_ACCOUNT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | if (unlikely(!page)) { |
| 498 | ret = ret ? : -ENOMEM; |
| 499 | break; |
| 500 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 501 | pipe->tmp_page = page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | } |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 503 | |
| 504 | /* Allocate a slot in the ring in advance and attach an |
| 505 | * empty buffer. If we fault or otherwise fail to use |
| 506 | * it, either the reader will consume it or it'll still |
| 507 | * be there for the next write. |
| 508 | */ |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 509 | spin_lock_irq(&pipe->rd_wait.lock); |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 510 | |
| 511 | head = pipe->head; |
David Howells | 8f868d6 | 2019-12-05 22:30:37 +0000 | [diff] [blame] | 512 | if (pipe_full(head, pipe->tail, pipe->max_usage)) { |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 513 | spin_unlock_irq(&pipe->rd_wait.lock); |
David Howells | 8df4412 | 2019-10-07 16:30:51 +0100 | [diff] [blame] | 514 | continue; |
| 515 | } |
| 516 | |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 517 | pipe->head = head + 1; |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 518 | spin_unlock_irq(&pipe->rd_wait.lock); |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 519 | |
| 520 | /* Insert it into the buffer array */ |
| 521 | buf = &pipe->bufs[head & mask]; |
| 522 | buf->page = page; |
| 523 | buf->ops = &anon_pipe_buf_ops; |
| 524 | buf->offset = 0; |
| 525 | buf->len = 0; |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 526 | if (is_packetized(filp)) |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 527 | buf->flags = PIPE_BUF_FLAG_PACKET; |
Christoph Hellwig | f6dd975 | 2020-05-20 17:58:12 +0200 | [diff] [blame] | 528 | else |
| 529 | buf->flags = PIPE_BUF_FLAG_CAN_MERGE; |
David Howells | a194dfe | 2019-09-20 16:32:19 +0100 | [diff] [blame] | 530 | pipe->tmp_page = NULL; |
| 531 | |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 532 | copied = copy_page_from_iter(page, 0, PAGE_SIZE, from); |
| 533 | if (unlikely(copied < PAGE_SIZE && iov_iter_count(from))) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 534 | if (!ret) |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 535 | ret = -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | break; |
| 537 | } |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 538 | ret += copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | buf->offset = 0; |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 540 | buf->len = copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 542 | if (!iov_iter_count(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | break; |
| 544 | } |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 545 | |
David Howells | 8f868d6 | 2019-12-05 22:30:37 +0000 | [diff] [blame] | 546 | if (!pipe_full(head, pipe->tail, pipe->max_usage)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | continue; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 548 | |
| 549 | /* Wait for buffer space to become available. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | if (filp->f_flags & O_NONBLOCK) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 551 | if (!ret) |
| 552 | ret = -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | break; |
| 554 | } |
| 555 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 556 | if (!ret) |
| 557 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | break; |
| 559 | } |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 560 | |
| 561 | /* |
| 562 | * We're going to release the pipe lock and wait for more |
| 563 | * space. We wake up any readers if necessary, and then |
| 564 | * after waiting we need to re-check whether the pipe |
| 565 | * become empty while we dropped the lock. |
| 566 | */ |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 567 | __pipe_unlock(pipe); |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 568 | if (was_empty) |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 569 | wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 570 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 571 | wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe)); |
Linus Torvalds | 85190d1 | 2019-12-07 13:53:09 -0800 | [diff] [blame] | 572 | __pipe_lock(pipe); |
Jan Stancek | 0dd1e37 | 2019-12-22 13:33:24 +0100 | [diff] [blame] | 573 | was_empty = pipe_empty(pipe->head, pipe->tail); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 574 | wake_next_writer = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | } |
| 576 | out: |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 577 | if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
| 578 | wake_next_writer = false; |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 579 | __pipe_unlock(pipe); |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 580 | |
| 581 | /* |
| 582 | * If we do do a wakeup event, we do a 'sync' wakeup, because we |
| 583 | * want the reader to start processing things asap, rather than |
| 584 | * leave the data pending. |
| 585 | * |
| 586 | * This is particularly important for small writes, because of |
| 587 | * how (for example) the GNU make jobserver uses small writes to |
| 588 | * wake up pending jobs |
Linus Torvalds | 3b84482 | 2021-08-05 10:04:43 -0700 | [diff] [blame] | 589 | * |
| 590 | * Epoll nonsensically wants a wakeup whether the pipe |
| 591 | * was already empty or not. |
Linus Torvalds | 1b6b26a | 2019-12-07 12:14:28 -0800 | [diff] [blame] | 592 | */ |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 593 | if (was_empty || pipe->poll_usage) |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 594 | wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); |
Linus Torvalds | fe67f4d | 2021-08-24 10:39:25 -0700 | [diff] [blame] | 595 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 596 | if (wake_next_writer) |
| 597 | wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); |
Dmitry Monakhov | 7e775f4 | 2014-01-23 15:55:21 -0800 | [diff] [blame] | 598 | if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) { |
Josef Bacik | c3b2da3 | 2012-03-26 09:59:21 -0400 | [diff] [blame] | 599 | int err = file_update_time(filp); |
| 600 | if (err) |
| 601 | ret = err; |
Dmitry Monakhov | 7e775f4 | 2014-01-23 15:55:21 -0800 | [diff] [blame] | 602 | sb_end_write(file_inode(filp)->i_sb); |
Josef Bacik | c3b2da3 | 2012-03-26 09:59:21 -0400 | [diff] [blame] | 603 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | return ret; |
| 605 | } |
| 606 | |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 607 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | { |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 609 | struct pipe_inode_info *pipe = filp->private_data; |
Andrei Vagin | aeb213c | 2022-03-23 16:06:20 -0700 | [diff] [blame] | 610 | unsigned int count, head, tail, mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | |
| 612 | switch (cmd) { |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 613 | case FIONREAD: |
| 614 | __pipe_lock(pipe); |
| 615 | count = 0; |
| 616 | head = pipe->head; |
| 617 | tail = pipe->tail; |
| 618 | mask = pipe->ring_size - 1; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 619 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 620 | while (tail != head) { |
| 621 | count += pipe->bufs[tail & mask].len; |
| 622 | tail++; |
| 623 | } |
| 624 | __pipe_unlock(pipe); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 625 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 626 | return put_user(count, (int __user *)arg); |
| 627 | |
| 628 | #ifdef CONFIG_WATCH_QUEUE |
| 629 | case IOC_WATCH_QUEUE_SET_SIZE: { |
| 630 | int ret; |
| 631 | __pipe_lock(pipe); |
| 632 | ret = watch_queue_set_size(pipe, arg); |
| 633 | __pipe_unlock(pipe); |
| 634 | return ret; |
| 635 | } |
| 636 | |
| 637 | case IOC_WATCH_QUEUE_SET_FILTER: |
| 638 | return watch_queue_set_filter( |
| 639 | pipe, (struct watch_notification_filter __user *)arg); |
| 640 | #endif |
| 641 | |
| 642 | default: |
| 643 | return -ENOIOCTLCMD; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | } |
| 645 | } |
| 646 | |
Christoph Hellwig | dd67081 | 2017-12-31 16:42:12 +0100 | [diff] [blame] | 647 | /* No kernel lock held - fine */ |
Linus Torvalds | a11e1d4 | 2018-06-28 09:43:44 -0700 | [diff] [blame] | 648 | static __poll_t |
| 649 | pipe_poll(struct file *filp, poll_table *wait) |
Christoph Hellwig | dd67081 | 2017-12-31 16:42:12 +0100 | [diff] [blame] | 650 | { |
Linus Torvalds | a11e1d4 | 2018-06-28 09:43:44 -0700 | [diff] [blame] | 651 | __poll_t mask; |
Christoph Hellwig | dd67081 | 2017-12-31 16:42:12 +0100 | [diff] [blame] | 652 | struct pipe_inode_info *pipe = filp->private_data; |
Linus Torvalds | ad910e3 | 2019-12-07 10:41:17 -0800 | [diff] [blame] | 653 | unsigned int head, tail; |
Linus Torvalds | a11e1d4 | 2018-06-28 09:43:44 -0700 | [diff] [blame] | 654 | |
Linus Torvalds | 3b84482 | 2021-08-05 10:04:43 -0700 | [diff] [blame] | 655 | /* Epoll has some historical nasty semantics, this enables them */ |
Kuniyuki Iwashima | f485922 | 2022-04-29 14:38:01 -0700 | [diff] [blame] | 656 | WRITE_ONCE(pipe->poll_usage, true); |
Linus Torvalds | 3b84482 | 2021-08-05 10:04:43 -0700 | [diff] [blame] | 657 | |
Linus Torvalds | ad910e3 | 2019-12-07 10:41:17 -0800 | [diff] [blame] | 658 | /* |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 659 | * Reading pipe state only -- no need for acquiring the semaphore. |
Linus Torvalds | ad910e3 | 2019-12-07 10:41:17 -0800 | [diff] [blame] | 660 | * |
| 661 | * But because this is racy, the code has to add the |
| 662 | * entry to the poll table _first_ .. |
| 663 | */ |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 664 | if (filp->f_mode & FMODE_READ) |
| 665 | poll_wait(filp, &pipe->rd_wait, wait); |
| 666 | if (filp->f_mode & FMODE_WRITE) |
| 667 | poll_wait(filp, &pipe->wr_wait, wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | |
Linus Torvalds | ad910e3 | 2019-12-07 10:41:17 -0800 | [diff] [blame] | 669 | /* |
| 670 | * .. and only then can you do the racy tests. That way, |
| 671 | * if something changes and you got it wrong, the poll |
| 672 | * table entry will wake you up and fix it. |
| 673 | */ |
| 674 | head = READ_ONCE(pipe->head); |
| 675 | tail = READ_ONCE(pipe->tail); |
| 676 | |
Linus Torvalds | a11e1d4 | 2018-06-28 09:43:44 -0700 | [diff] [blame] | 677 | mask = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | if (filp->f_mode & FMODE_READ) { |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 679 | if (!pipe_empty(head, tail)) |
| 680 | mask |= EPOLLIN | EPOLLRDNORM; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 681 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
Linus Torvalds | a9a0884 | 2018-02-11 14:34:03 -0800 | [diff] [blame] | 682 | mask |= EPOLLHUP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | } |
| 684 | |
| 685 | if (filp->f_mode & FMODE_WRITE) { |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 686 | if (!pipe_full(head, tail, pipe->max_usage)) |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 687 | mask |= EPOLLOUT | EPOLLWRNORM; |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 688 | /* |
Linus Torvalds | a9a0884 | 2018-02-11 14:34:03 -0800 | [diff] [blame] | 689 | * Most Unices do not set EPOLLERR for FIFOs but on Linux they |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 690 | * behave exactly like pipes for poll(). |
| 691 | */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 692 | if (!pipe->readers) |
Linus Torvalds | a9a0884 | 2018-02-11 14:34:03 -0800 | [diff] [blame] | 693 | mask |= EPOLLERR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | } |
| 695 | |
| 696 | return mask; |
| 697 | } |
| 698 | |
Linus Torvalds | b0d8d22 | 2013-12-02 09:44:51 -0800 | [diff] [blame] | 699 | static void put_pipe_info(struct inode *inode, struct pipe_inode_info *pipe) |
| 700 | { |
| 701 | int kill = 0; |
| 702 | |
| 703 | spin_lock(&inode->i_lock); |
| 704 | if (!--pipe->files) { |
| 705 | inode->i_pipe = NULL; |
| 706 | kill = 1; |
| 707 | } |
| 708 | spin_unlock(&inode->i_lock); |
| 709 | |
| 710 | if (kill) |
| 711 | free_pipe_info(pipe); |
| 712 | } |
| 713 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | static int |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 715 | pipe_release(struct inode *inode, struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | { |
Linus Torvalds | b0d8d22 | 2013-12-02 09:44:51 -0800 | [diff] [blame] | 717 | struct pipe_inode_info *pipe = file->private_data; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 718 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 719 | __pipe_lock(pipe); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 720 | if (file->f_mode & FMODE_READ) |
| 721 | pipe->readers--; |
| 722 | if (file->f_mode & FMODE_WRITE) |
| 723 | pipe->writers--; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 724 | |
Linus Torvalds | 6551d5c | 2020-02-18 10:12:58 -0800 | [diff] [blame] | 725 | /* Was that the last reader or writer, but not the other side? */ |
| 726 | if (!pipe->readers != !pipe->writers) { |
| 727 | wake_up_interruptible_all(&pipe->rd_wait); |
| 728 | wake_up_interruptible_all(&pipe->wr_wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 729 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 730 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | } |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 732 | __pipe_unlock(pipe); |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 733 | |
Linus Torvalds | b0d8d22 | 2013-12-02 09:44:51 -0800 | [diff] [blame] | 734 | put_pipe_info(inode, pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | return 0; |
| 736 | } |
| 737 | |
| 738 | static int |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 739 | pipe_fasync(int fd, struct file *filp, int on) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | { |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 741 | struct pipe_inode_info *pipe = filp->private_data; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 742 | int retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 744 | __pipe_lock(pipe); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 745 | if (filp->f_mode & FMODE_READ) |
| 746 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
| 747 | if ((filp->f_mode & FMODE_WRITE) && retval >= 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 748 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 749 | if (retval < 0 && (filp->f_mode & FMODE_READ)) |
| 750 | /* this can happen only if on == T */ |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 751 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
| 752 | } |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 753 | __pipe_unlock(pipe); |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 754 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | } |
| 756 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 757 | unsigned long account_pipe_buffers(struct user_struct *user, |
| 758 | unsigned long old, unsigned long new) |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 759 | { |
Michael Kerrisk (man-pages) | 9c87bcf | 2016-10-11 13:53:40 -0700 | [diff] [blame] | 760 | return atomic_long_add_return(new - old, &user->pipe_bufs); |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 761 | } |
| 762 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 763 | bool too_many_pipe_buffers_soft(unsigned long user_bufs) |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 764 | { |
Eric Biggers | f734076 | 2018-02-06 15:42:08 -0800 | [diff] [blame] | 765 | unsigned long soft_limit = READ_ONCE(pipe_user_pages_soft); |
| 766 | |
| 767 | return soft_limit && user_bufs > soft_limit; |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 768 | } |
| 769 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 770 | bool too_many_pipe_buffers_hard(unsigned long user_bufs) |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 771 | { |
Eric Biggers | f734076 | 2018-02-06 15:42:08 -0800 | [diff] [blame] | 772 | unsigned long hard_limit = READ_ONCE(pipe_user_pages_hard); |
| 773 | |
| 774 | return hard_limit && user_bufs > hard_limit; |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 775 | } |
| 776 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 777 | bool pipe_is_unprivileged_user(void) |
Eric Biggers | 85c2dd5 | 2018-02-06 15:41:53 -0800 | [diff] [blame] | 778 | { |
| 779 | return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); |
| 780 | } |
| 781 | |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame] | 782 | struct pipe_inode_info *alloc_pipe_info(void) |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 783 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 784 | struct pipe_inode_info *pipe; |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 785 | unsigned long pipe_bufs = PIPE_DEF_BUFFERS; |
| 786 | struct user_struct *user = get_current_user(); |
Michael Kerrisk (man-pages) | 9c87bcf | 2016-10-11 13:53:40 -0700 | [diff] [blame] | 787 | unsigned long user_bufs; |
Eric Biggers | f734076 | 2018-02-06 15:42:08 -0800 | [diff] [blame] | 788 | unsigned int max_size = READ_ONCE(pipe_max_size); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 789 | |
Vladimir Davydov | d86133b | 2016-07-26 15:24:33 -0700 | [diff] [blame] | 790 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL_ACCOUNT); |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 791 | if (pipe == NULL) |
| 792 | goto out_free_uid; |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 793 | |
Eric Biggers | f734076 | 2018-02-06 15:42:08 -0800 | [diff] [blame] | 794 | if (pipe_bufs * PAGE_SIZE > max_size && !capable(CAP_SYS_RESOURCE)) |
| 795 | pipe_bufs = max_size >> PAGE_SHIFT; |
Michael Kerrisk (man-pages) | 086e774 | 2016-10-11 13:53:43 -0700 | [diff] [blame] | 796 | |
Michael Kerrisk (man-pages) | 9c87bcf | 2016-10-11 13:53:40 -0700 | [diff] [blame] | 797 | user_bufs = account_pipe_buffers(user, 0, pipe_bufs); |
Michael Kerrisk (man-pages) | a005ca0 | 2016-10-11 13:53:37 -0700 | [diff] [blame] | 798 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 799 | if (too_many_pipe_buffers_soft(user_bufs) && pipe_is_unprivileged_user()) { |
Alex Xu (Hello71) | 46c4c9d | 2021-08-05 10:40:47 -0400 | [diff] [blame] | 800 | user_bufs = account_pipe_buffers(user, pipe_bufs, PIPE_MIN_DEF_BUFFERS); |
| 801 | pipe_bufs = PIPE_MIN_DEF_BUFFERS; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 802 | } |
| 803 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 804 | if (too_many_pipe_buffers_hard(user_bufs) && pipe_is_unprivileged_user()) |
Michael Kerrisk (man-pages) | a005ca0 | 2016-10-11 13:53:37 -0700 | [diff] [blame] | 805 | goto out_revert_acct; |
| 806 | |
Linus Torvalds | 906f904 | 2022-04-20 12:07:53 -0700 | [diff] [blame] | 807 | pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer), |
Michael Kerrisk (man-pages) | a005ca0 | 2016-10-11 13:53:37 -0700 | [diff] [blame] | 808 | GFP_KERNEL_ACCOUNT); |
| 809 | |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 810 | if (pipe->bufs) { |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 811 | init_waitqueue_head(&pipe->rd_wait); |
| 812 | init_waitqueue_head(&pipe->wr_wait); |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 813 | pipe->r_counter = pipe->w_counter = 1; |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 814 | pipe->max_usage = pipe_bufs; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 815 | pipe->ring_size = pipe_bufs; |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 816 | pipe->nr_accounted = pipe_bufs; |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 817 | pipe->user = user; |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 818 | mutex_init(&pipe->mutex); |
| 819 | return pipe; |
| 820 | } |
| 821 | |
Michael Kerrisk (man-pages) | a005ca0 | 2016-10-11 13:53:37 -0700 | [diff] [blame] | 822 | out_revert_acct: |
Michael Kerrisk (man-pages) | 9c87bcf | 2016-10-11 13:53:40 -0700 | [diff] [blame] | 823 | (void) account_pipe_buffers(user, pipe_bufs, 0); |
Michael Kerrisk (man-pages) | 09b4d19 | 2016-10-11 13:53:34 -0700 | [diff] [blame] | 824 | kfree(pipe); |
| 825 | out_free_uid: |
| 826 | free_uid(user); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 827 | return NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 828 | } |
| 829 | |
Al Viro | 4b8a8f1 | 2013-03-21 11:06:46 -0400 | [diff] [blame] | 830 | void free_pipe_info(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 831 | { |
Andrei Vagin | aeb213c | 2022-03-23 16:06:20 -0700 | [diff] [blame] | 832 | unsigned int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 833 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 834 | #ifdef CONFIG_WATCH_QUEUE |
David Howells | db8facf | 2022-03-11 13:23:38 +0000 | [diff] [blame] | 835 | if (pipe->watch_queue) |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 836 | watch_queue_clear(pipe->watch_queue); |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 837 | #endif |
| 838 | |
| 839 | (void) account_pipe_buffers(pipe->user, pipe->nr_accounted, 0); |
Willy Tarreau | 759c011 | 2016-01-18 16:36:09 +0100 | [diff] [blame] | 840 | free_uid(pipe->user); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 841 | for (i = 0; i < pipe->ring_size; i++) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 842 | struct pipe_buffer *buf = pipe->bufs + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 843 | if (buf->ops) |
Miklos Szeredi | a779638 | 2016-09-27 10:45:12 +0200 | [diff] [blame] | 844 | pipe_buf_release(pipe, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 845 | } |
David Howells | db8facf | 2022-03-11 13:23:38 +0000 | [diff] [blame] | 846 | #ifdef CONFIG_WATCH_QUEUE |
| 847 | if (pipe->watch_queue) |
| 848 | put_watch_queue(pipe->watch_queue); |
| 849 | #endif |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 850 | if (pipe->tmp_page) |
| 851 | __free_page(pipe->tmp_page); |
Linus Torvalds | 906f904 | 2022-04-20 12:07:53 -0700 | [diff] [blame] | 852 | kfree(pipe->bufs); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 853 | kfree(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 854 | } |
| 855 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 856 | static struct vfsmount *pipe_mnt __read_mostly; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 857 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 858 | /* |
| 859 | * pipefs_dname() is called from d_path(). |
| 860 | */ |
| 861 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) |
| 862 | { |
Al Viro | 0f60d28 | 2022-01-30 15:03:49 -0500 | [diff] [blame] | 863 | return dynamic_dname(buffer, buflen, "pipe:[%lu]", |
David Howells | 75c3cfa | 2015-03-17 22:26:12 +0000 | [diff] [blame] | 864 | d_inode(dentry)->i_ino); |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 865 | } |
| 866 | |
Al Viro | 3ba13d1 | 2009-02-20 06:02:22 +0000 | [diff] [blame] | 867 | static const struct dentry_operations pipefs_dentry_operations = { |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 868 | .d_dname = pipefs_dname, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | }; |
| 870 | |
| 871 | static struct inode * get_pipe_inode(void) |
| 872 | { |
Eric Dumazet | a209dfc | 2011-07-26 11:36:34 +0200 | [diff] [blame] | 873 | struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 874 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | |
| 876 | if (!inode) |
| 877 | goto fail_inode; |
| 878 | |
Christoph Hellwig | 85fe402 | 2010-10-23 11:19:54 -0400 | [diff] [blame] | 879 | inode->i_ino = get_next_ino(); |
| 880 | |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame] | 881 | pipe = alloc_pipe_info(); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 882 | if (!pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | goto fail_iput; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 884 | |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 885 | inode->i_pipe = pipe; |
| 886 | pipe->files = 2; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 887 | pipe->readers = pipe->writers = 1; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 888 | inode->i_fop = &pipefifo_fops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 889 | |
| 890 | /* |
| 891 | * Mark the inode dirty from the very beginning, |
| 892 | * that way it will never be moved to the dirty |
| 893 | * list because "mark_inode_dirty()" will think |
| 894 | * that it already _is_ on the dirty list. |
| 895 | */ |
| 896 | inode->i_state = I_DIRTY; |
| 897 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 898 | inode->i_uid = current_fsuid(); |
| 899 | inode->i_gid = current_fsgid(); |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 900 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 901 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | return inode; |
| 903 | |
| 904 | fail_iput: |
| 905 | iput(inode); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 906 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | fail_inode: |
| 908 | return NULL; |
| 909 | } |
| 910 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 911 | int create_pipe_files(struct file **res, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | { |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 913 | struct inode *inode = get_pipe_inode(); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 914 | struct file *f; |
Qian Cai | 8a018eb | 2020-10-01 08:50:55 -0400 | [diff] [blame] | 915 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 917 | if (!inode) |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 918 | return -ENFILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 919 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 920 | if (flags & O_NOTIFICATION_PIPE) { |
Qian Cai | 8a018eb | 2020-10-01 08:50:55 -0400 | [diff] [blame] | 921 | error = watch_queue_init(inode->i_pipe); |
| 922 | if (error) { |
| 923 | free_pipe_info(inode->i_pipe); |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 924 | iput(inode); |
Qian Cai | 8a018eb | 2020-10-01 08:50:55 -0400 | [diff] [blame] | 925 | return error; |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 926 | } |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 927 | } |
| 928 | |
Al Viro | 152b637 | 2018-06-09 10:05:18 -0400 | [diff] [blame] | 929 | f = alloc_file_pseudo(inode, pipe_mnt, "", |
| 930 | O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)), |
| 931 | &pipefifo_fops); |
Eric Biggers | e9bb1f9 | 2015-10-17 16:26:08 -0500 | [diff] [blame] | 932 | if (IS_ERR(f)) { |
Al Viro | 152b637 | 2018-06-09 10:05:18 -0400 | [diff] [blame] | 933 | free_pipe_info(inode->i_pipe); |
| 934 | iput(inode); |
| 935 | return PTR_ERR(f); |
Eric Biggers | e9bb1f9 | 2015-10-17 16:26:08 -0500 | [diff] [blame] | 936 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 937 | |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 938 | f->private_data = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | |
Al Viro | 183266f | 2018-06-17 14:15:10 -0400 | [diff] [blame] | 940 | res[0] = alloc_file_clone(f, O_RDONLY | (flags & O_NONBLOCK), |
| 941 | &pipefifo_fops); |
Eric Biggers | e9bb1f9 | 2015-10-17 16:26:08 -0500 | [diff] [blame] | 942 | if (IS_ERR(res[0])) { |
Al Viro | b10a4a9 | 2018-07-09 02:29:58 -0400 | [diff] [blame] | 943 | put_pipe_info(inode, inode->i_pipe); |
| 944 | fput(f); |
| 945 | return PTR_ERR(res[0]); |
Eric Biggers | e9bb1f9 | 2015-10-17 16:26:08 -0500 | [diff] [blame] | 946 | } |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 947 | res[0]->private_data = inode->i_pipe; |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 948 | res[1] = f; |
Linus Torvalds | d8e464e | 2019-11-17 11:20:48 -0800 | [diff] [blame] | 949 | stream_open(inode, res[0]); |
| 950 | stream_open(inode, res[1]); |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 951 | return 0; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 952 | } |
| 953 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 954 | static int __do_pipe_flags(int *fd, struct file **files, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 955 | { |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 956 | int error; |
| 957 | int fdw, fdr; |
| 958 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 959 | if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT | O_NOTIFICATION_PIPE)) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 960 | return -EINVAL; |
| 961 | |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 962 | error = create_pipe_files(files, flags); |
| 963 | if (error) |
| 964 | return error; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 965 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 966 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 967 | if (error < 0) |
| 968 | goto err_read_pipe; |
| 969 | fdr = error; |
| 970 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 971 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 972 | if (error < 0) |
| 973 | goto err_fdr; |
| 974 | fdw = error; |
| 975 | |
Al Viro | 157cf64 | 2008-12-14 04:57:47 -0500 | [diff] [blame] | 976 | audit_fd_pair(fdr, fdw); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 977 | fd[0] = fdr; |
| 978 | fd[1] = fdw; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | return 0; |
| 980 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 981 | err_fdr: |
| 982 | put_unused_fd(fdr); |
| 983 | err_read_pipe: |
Al Viro | e4fad8e | 2012-07-21 15:33:25 +0400 | [diff] [blame] | 984 | fput(files[0]); |
| 985 | fput(files[1]); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 986 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | } |
| 988 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 989 | int do_pipe_flags(int *fd, int flags) |
| 990 | { |
| 991 | struct file *files[2]; |
| 992 | int error = __do_pipe_flags(fd, files, flags); |
| 993 | if (!error) { |
| 994 | fd_install(fd[0], files[0]); |
| 995 | fd_install(fd[1], files[1]); |
| 996 | } |
| 997 | return error; |
| 998 | } |
| 999 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1000 | /* |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1001 | * sys_pipe() is the normal C calling standard for creating |
| 1002 | * a pipe. It's not the way Unix traditionally does this, though. |
| 1003 | */ |
Dominik Brodowski | 0a216dd | 2018-03-11 11:34:28 +0100 | [diff] [blame] | 1004 | static int do_pipe2(int __user *fildes, int flags) |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1005 | { |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 1006 | struct file *files[2]; |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1007 | int fd[2]; |
| 1008 | int error; |
| 1009 | |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 1010 | error = __do_pipe_flags(fd, files, flags); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1011 | if (!error) { |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 1012 | if (unlikely(copy_to_user(fildes, fd, sizeof(fd)))) { |
| 1013 | fput(files[0]); |
| 1014 | fput(files[1]); |
| 1015 | put_unused_fd(fd[0]); |
| 1016 | put_unused_fd(fd[1]); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1017 | error = -EFAULT; |
Al Viro | 5b249b1 | 2012-08-19 12:17:29 -0400 | [diff] [blame] | 1018 | } else { |
| 1019 | fd_install(fd[0], files[0]); |
| 1020 | fd_install(fd[1], files[1]); |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 1021 | } |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1022 | } |
| 1023 | return error; |
| 1024 | } |
| 1025 | |
Dominik Brodowski | 0a216dd | 2018-03-11 11:34:28 +0100 | [diff] [blame] | 1026 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
| 1027 | { |
| 1028 | return do_pipe2(fildes, flags); |
| 1029 | } |
| 1030 | |
Heiko Carstens | 2b66421 | 2009-01-14 14:14:35 +0100 | [diff] [blame] | 1031 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1032 | { |
Dominik Brodowski | 0a216dd | 2018-03-11 11:34:28 +0100 | [diff] [blame] | 1033 | return do_pipe2(fildes, 0); |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1034 | } |
| 1035 | |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1036 | /* |
| 1037 | * This is the stupid "wait for pipe to be readable or writable" |
| 1038 | * model. |
| 1039 | * |
| 1040 | * See pipe_read/write() for the proper kind of exclusive wait, |
| 1041 | * but that requires that we wake up any other readers/writers |
| 1042 | * if we then do not end up reading everything (ie the whole |
| 1043 | * "wake_next_reader/writer" logic in pipe_read/write()). |
| 1044 | */ |
| 1045 | void pipe_wait_readable(struct pipe_inode_info *pipe) |
| 1046 | { |
| 1047 | pipe_unlock(pipe); |
| 1048 | wait_event_interruptible(pipe->rd_wait, pipe_readable(pipe)); |
| 1049 | pipe_lock(pipe); |
| 1050 | } |
| 1051 | |
| 1052 | void pipe_wait_writable(struct pipe_inode_info *pipe) |
| 1053 | { |
| 1054 | pipe_unlock(pipe); |
| 1055 | wait_event_interruptible(pipe->wr_wait, pipe_writable(pipe)); |
| 1056 | pipe_lock(pipe); |
| 1057 | } |
| 1058 | |
| 1059 | /* |
| 1060 | * This depends on both the wait (here) and the wakeup (wake_up_partner) |
| 1061 | * holding the pipe lock, so "*cnt" is stable and we know a wakeup cannot |
| 1062 | * race with the count check and waitqueue prep. |
| 1063 | * |
| 1064 | * Normally in order to avoid races, you'd do the prepare_to_wait() first, |
| 1065 | * then check the condition you're waiting for, and only then sleep. But |
| 1066 | * because of the pipe lock, we can check the condition before being on |
| 1067 | * the wait queue. |
| 1068 | * |
| 1069 | * We use the 'rd_wait' waitqueue for pipe partner waiting. |
| 1070 | */ |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1071 | static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1072 | { |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1073 | DEFINE_WAIT(rdwait); |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1074 | int cur = *cnt; |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1075 | |
| 1076 | while (cur == *cnt) { |
Linus Torvalds | 472e5b0 | 2020-10-01 19:14:36 -0700 | [diff] [blame] | 1077 | prepare_to_wait(&pipe->rd_wait, &rdwait, TASK_INTERRUPTIBLE); |
| 1078 | pipe_unlock(pipe); |
| 1079 | schedule(); |
| 1080 | finish_wait(&pipe->rd_wait, &rdwait); |
| 1081 | pipe_lock(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1082 | if (signal_pending(current)) |
| 1083 | break; |
| 1084 | } |
| 1085 | return cur == *cnt ? -ERESTARTSYS : 0; |
| 1086 | } |
| 1087 | |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1088 | static void wake_up_partner(struct pipe_inode_info *pipe) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1089 | { |
Linus Torvalds | 6551d5c | 2020-02-18 10:12:58 -0800 | [diff] [blame] | 1090 | wake_up_interruptible_all(&pipe->rd_wait); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1091 | } |
| 1092 | |
| 1093 | static int fifo_open(struct inode *inode, struct file *filp) |
| 1094 | { |
| 1095 | struct pipe_inode_info *pipe; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1096 | bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC; |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1097 | int ret; |
| 1098 | |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1099 | filp->f_version = 0; |
| 1100 | |
| 1101 | spin_lock(&inode->i_lock); |
| 1102 | if (inode->i_pipe) { |
| 1103 | pipe = inode->i_pipe; |
| 1104 | pipe->files++; |
| 1105 | spin_unlock(&inode->i_lock); |
| 1106 | } else { |
| 1107 | spin_unlock(&inode->i_lock); |
Al Viro | 7bee130 | 2013-03-21 11:04:15 -0400 | [diff] [blame] | 1108 | pipe = alloc_pipe_info(); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1109 | if (!pipe) |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1110 | return -ENOMEM; |
| 1111 | pipe->files = 1; |
| 1112 | spin_lock(&inode->i_lock); |
| 1113 | if (unlikely(inode->i_pipe)) { |
| 1114 | inode->i_pipe->files++; |
| 1115 | spin_unlock(&inode->i_lock); |
Al Viro | 4b8a8f1 | 2013-03-21 11:06:46 -0400 | [diff] [blame] | 1116 | free_pipe_info(pipe); |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1117 | pipe = inode->i_pipe; |
| 1118 | } else { |
| 1119 | inode->i_pipe = pipe; |
| 1120 | spin_unlock(&inode->i_lock); |
| 1121 | } |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1122 | } |
Al Viro | de32ec4 | 2013-03-21 11:16:56 -0400 | [diff] [blame] | 1123 | filp->private_data = pipe; |
Al Viro | ba5bb14 | 2013-03-21 02:21:19 -0400 | [diff] [blame] | 1124 | /* OK, we have a pipe and it's pinned down */ |
| 1125 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1126 | __pipe_lock(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1127 | |
| 1128 | /* We can only do regular read/write on fifos */ |
Linus Torvalds | d8e464e | 2019-11-17 11:20:48 -0800 | [diff] [blame] | 1129 | stream_open(inode, filp); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1130 | |
Linus Torvalds | d8e464e | 2019-11-17 11:20:48 -0800 | [diff] [blame] | 1131 | switch (filp->f_mode & (FMODE_READ | FMODE_WRITE)) { |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1132 | case FMODE_READ: |
| 1133 | /* |
| 1134 | * O_RDONLY |
| 1135 | * POSIX.1 says that O_NONBLOCK means return with the FIFO |
| 1136 | * opened, even when there is no process writing the FIFO. |
| 1137 | */ |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1138 | pipe->r_counter++; |
| 1139 | if (pipe->readers++ == 0) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1140 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1141 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1142 | if (!is_pipe && !pipe->writers) { |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1143 | if ((filp->f_flags & O_NONBLOCK)) { |
Linus Torvalds | a9a0884 | 2018-02-11 14:34:03 -0800 | [diff] [blame] | 1144 | /* suppress EPOLLHUP until we have |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1145 | * seen a writer */ |
| 1146 | filp->f_version = pipe->w_counter; |
| 1147 | } else { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1148 | if (wait_for_partner(pipe, &pipe->w_counter)) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1149 | goto err_rd; |
| 1150 | } |
| 1151 | } |
| 1152 | break; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1153 | |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1154 | case FMODE_WRITE: |
| 1155 | /* |
| 1156 | * O_WRONLY |
| 1157 | * POSIX.1 says that O_NONBLOCK means return -1 with |
| 1158 | * errno=ENXIO when there is no process reading the FIFO. |
| 1159 | */ |
| 1160 | ret = -ENXIO; |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1161 | if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1162 | goto err; |
| 1163 | |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1164 | pipe->w_counter++; |
| 1165 | if (!pipe->writers++) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1166 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1167 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1168 | if (!is_pipe && !pipe->readers) { |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1169 | if (wait_for_partner(pipe, &pipe->r_counter)) |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1170 | goto err_wr; |
| 1171 | } |
| 1172 | break; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1173 | |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1174 | case FMODE_READ | FMODE_WRITE: |
| 1175 | /* |
| 1176 | * O_RDWR |
| 1177 | * POSIX.1 leaves this case "undefined" when O_NONBLOCK is set. |
| 1178 | * This implementation will NEVER block on a O_RDWR open, since |
| 1179 | * the process can at least talk to itself. |
| 1180 | */ |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1181 | |
| 1182 | pipe->readers++; |
| 1183 | pipe->writers++; |
| 1184 | pipe->r_counter++; |
| 1185 | pipe->w_counter++; |
| 1186 | if (pipe->readers == 1 || pipe->writers == 1) |
Al Viro | fc7478a | 2013-03-21 02:07:59 -0400 | [diff] [blame] | 1187 | wake_up_partner(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1188 | break; |
| 1189 | |
| 1190 | default: |
| 1191 | ret = -EINVAL; |
| 1192 | goto err; |
| 1193 | } |
| 1194 | |
| 1195 | /* Ok! */ |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1196 | __pipe_unlock(pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1197 | return 0; |
| 1198 | |
| 1199 | err_rd: |
| 1200 | if (!--pipe->readers) |
Linus Torvalds | 0ddad21 | 2019-12-09 09:48:27 -0800 | [diff] [blame] | 1201 | wake_up_interruptible(&pipe->wr_wait); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1202 | ret = -ERESTARTSYS; |
| 1203 | goto err; |
| 1204 | |
| 1205 | err_wr: |
| 1206 | if (!--pipe->writers) |
Linus Torvalds | 6551d5c | 2020-02-18 10:12:58 -0800 | [diff] [blame] | 1207 | wake_up_interruptible_all(&pipe->rd_wait); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1208 | ret = -ERESTARTSYS; |
| 1209 | goto err; |
| 1210 | |
| 1211 | err: |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1212 | __pipe_unlock(pipe); |
Linus Torvalds | b0d8d22 | 2013-12-02 09:44:51 -0800 | [diff] [blame] | 1213 | |
| 1214 | put_pipe_info(inode, pipe); |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1215 | return ret; |
| 1216 | } |
| 1217 | |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1218 | const struct file_operations pipefifo_fops = { |
| 1219 | .open = fifo_open, |
| 1220 | .llseek = no_llseek, |
Al Viro | fb9096a | 2014-04-02 19:56:54 -0400 | [diff] [blame] | 1221 | .read_iter = pipe_read, |
Al Viro | f0d1bec | 2014-04-03 15:05:18 -0400 | [diff] [blame] | 1222 | .write_iter = pipe_write, |
Linus Torvalds | a11e1d4 | 2018-06-28 09:43:44 -0700 | [diff] [blame] | 1223 | .poll = pipe_poll, |
Al Viro | 599a0ac | 2013-03-12 09:58:10 -0400 | [diff] [blame] | 1224 | .unlocked_ioctl = pipe_ioctl, |
| 1225 | .release = pipe_release, |
| 1226 | .fasync = pipe_fasync, |
Johannes Berg | f8ad818 | 2021-01-25 10:16:15 +0100 | [diff] [blame] | 1227 | .splice_write = iter_file_splice_write, |
Al Viro | f776c73 | 2013-03-12 09:46:27 -0400 | [diff] [blame] | 1228 | }; |
| 1229 | |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1230 | /* |
Michael Kerrisk (man-pages) | f491bd7 | 2016-10-11 13:53:22 -0700 | [diff] [blame] | 1231 | * Currently we rely on the pipe array holding a power-of-2 number |
Joe Lawrence | d3f14c4 | 2017-11-17 15:29:21 -0800 | [diff] [blame] | 1232 | * of pages. Returns 0 on error. |
Michael Kerrisk (man-pages) | f491bd7 | 2016-10-11 13:53:22 -0700 | [diff] [blame] | 1233 | */ |
Eric Biggers | 96e99be40 | 2018-02-06 15:42:00 -0800 | [diff] [blame] | 1234 | unsigned int round_pipe_size(unsigned long size) |
Michael Kerrisk (man-pages) | f491bd7 | 2016-10-11 13:53:22 -0700 | [diff] [blame] | 1235 | { |
Eric Biggers | c4fed5a | 2018-02-06 15:42:05 -0800 | [diff] [blame] | 1236 | if (size > (1U << 31)) |
Eric Biggers | 96e99be40 | 2018-02-06 15:42:00 -0800 | [diff] [blame] | 1237 | return 0; |
| 1238 | |
Eric Biggers | 4c2e4be | 2018-02-06 15:41:45 -0800 | [diff] [blame] | 1239 | /* Minimum pipe size, as required by POSIX */ |
| 1240 | if (size < PAGE_SIZE) |
Eric Biggers | c4fed5a | 2018-02-06 15:42:05 -0800 | [diff] [blame] | 1241 | return PAGE_SIZE; |
Joe Lawrence | d3f14c4 | 2017-11-17 15:29:21 -0800 | [diff] [blame] | 1242 | |
Eric Biggers | c4fed5a | 2018-02-06 15:42:05 -0800 | [diff] [blame] | 1243 | return roundup_pow_of_two(size); |
Michael Kerrisk (man-pages) | f491bd7 | 2016-10-11 13:53:22 -0700 | [diff] [blame] | 1244 | } |
| 1245 | |
| 1246 | /* |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1247 | * Resize the pipe ring to a number of slots. |
David Howells | 189b0dd | 2022-05-26 07:34:52 +0100 | [diff] [blame] | 1248 | * |
| 1249 | * Note the pipe can be reduced in capacity, but only if the current |
| 1250 | * occupancy doesn't exceed nr_slots; if it does, EBUSY will be |
| 1251 | * returned instead. |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1252 | */ |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1253 | int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1254 | { |
| 1255 | struct pipe_buffer *bufs; |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1256 | unsigned int head, tail, mask, n; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1257 | |
Linus Torvalds | 906f904 | 2022-04-20 12:07:53 -0700 | [diff] [blame] | 1258 | bufs = kcalloc(nr_slots, sizeof(*bufs), |
| 1259 | GFP_KERNEL_ACCOUNT | __GFP_NOWARN); |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1260 | if (unlikely(!bufs)) |
| 1261 | return -ENOMEM; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1262 | |
David Howells | 189b0dd | 2022-05-26 07:34:52 +0100 | [diff] [blame] | 1263 | spin_lock_irq(&pipe->rd_wait.lock); |
| 1264 | mask = pipe->ring_size - 1; |
| 1265 | head = pipe->head; |
| 1266 | tail = pipe->tail; |
| 1267 | |
| 1268 | n = pipe_occupancy(head, tail); |
| 1269 | if (nr_slots < n) { |
| 1270 | spin_unlock_irq(&pipe->rd_wait.lock); |
| 1271 | kfree(bufs); |
| 1272 | return -EBUSY; |
| 1273 | } |
| 1274 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1275 | /* |
| 1276 | * The pipe array wraps around, so just start the new one at zero |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1277 | * and adjust the indices. |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1278 | */ |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1279 | if (n > 0) { |
| 1280 | unsigned int h = head & mask; |
| 1281 | unsigned int t = tail & mask; |
| 1282 | if (h > t) { |
| 1283 | memcpy(bufs, pipe->bufs + t, |
| 1284 | n * sizeof(struct pipe_buffer)); |
| 1285 | } else { |
| 1286 | unsigned int tsize = pipe->ring_size - t; |
| 1287 | if (h > 0) |
| 1288 | memcpy(bufs + tsize, pipe->bufs, |
| 1289 | h * sizeof(struct pipe_buffer)); |
| 1290 | memcpy(bufs, pipe->bufs + t, |
| 1291 | tsize * sizeof(struct pipe_buffer)); |
| 1292 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1293 | } |
| 1294 | |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1295 | head = n; |
| 1296 | tail = 0; |
| 1297 | |
Linus Torvalds | 906f904 | 2022-04-20 12:07:53 -0700 | [diff] [blame] | 1298 | kfree(pipe->bufs); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1299 | pipe->bufs = bufs; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1300 | pipe->ring_size = nr_slots; |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1301 | if (pipe->max_usage > nr_slots) |
| 1302 | pipe->max_usage = nr_slots; |
David Howells | 8cefc10 | 2019-11-15 13:30:32 +0000 | [diff] [blame] | 1303 | pipe->tail = tail; |
| 1304 | pipe->head = head; |
Linus Torvalds | 6551d5c | 2020-02-18 10:12:58 -0800 | [diff] [blame] | 1305 | |
David Howells | 189b0dd | 2022-05-26 07:34:52 +0100 | [diff] [blame] | 1306 | spin_unlock_irq(&pipe->rd_wait.lock); |
| 1307 | |
Linus Torvalds | 6551d5c | 2020-02-18 10:12:58 -0800 | [diff] [blame] | 1308 | /* This might have made more room for writers */ |
| 1309 | wake_up_interruptible(&pipe->wr_wait); |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1310 | return 0; |
| 1311 | } |
| 1312 | |
| 1313 | /* |
| 1314 | * Allocate a new array of pipe buffers and copy the info over. Returns the |
| 1315 | * pipe size if successful, or return -ERROR on error. |
| 1316 | */ |
| 1317 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) |
| 1318 | { |
| 1319 | unsigned long user_bufs; |
| 1320 | unsigned int nr_slots, size; |
| 1321 | long ret = 0; |
| 1322 | |
| 1323 | #ifdef CONFIG_WATCH_QUEUE |
| 1324 | if (pipe->watch_queue) |
| 1325 | return -EBUSY; |
| 1326 | #endif |
| 1327 | |
| 1328 | size = round_pipe_size(arg); |
| 1329 | nr_slots = size >> PAGE_SHIFT; |
| 1330 | |
| 1331 | if (!nr_slots) |
| 1332 | return -EINVAL; |
| 1333 | |
| 1334 | /* |
| 1335 | * If trying to increase the pipe capacity, check that an |
| 1336 | * unprivileged user is not trying to exceed various limits |
| 1337 | * (soft limit check here, hard limit check just below). |
| 1338 | * Decreasing the pipe capacity is always permitted, even |
| 1339 | * if the user is currently over a limit. |
| 1340 | */ |
| 1341 | if (nr_slots > pipe->max_usage && |
| 1342 | size > pipe_max_size && !capable(CAP_SYS_RESOURCE)) |
| 1343 | return -EPERM; |
| 1344 | |
| 1345 | user_bufs = account_pipe_buffers(pipe->user, pipe->nr_accounted, nr_slots); |
| 1346 | |
| 1347 | if (nr_slots > pipe->max_usage && |
| 1348 | (too_many_pipe_buffers_hard(user_bufs) || |
| 1349 | too_many_pipe_buffers_soft(user_bufs)) && |
| 1350 | pipe_is_unprivileged_user()) { |
| 1351 | ret = -EPERM; |
| 1352 | goto out_revert_acct; |
| 1353 | } |
| 1354 | |
| 1355 | ret = pipe_resize_ring(pipe, nr_slots); |
| 1356 | if (ret < 0) |
| 1357 | goto out_revert_acct; |
| 1358 | |
| 1359 | pipe->max_usage = nr_slots; |
| 1360 | pipe->nr_accounted = nr_slots; |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1361 | return pipe->max_usage * PAGE_SIZE; |
Michael Kerrisk (man-pages) | b0b91d1 | 2016-10-11 13:53:31 -0700 | [diff] [blame] | 1362 | |
| 1363 | out_revert_acct: |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1364 | (void) account_pipe_buffers(pipe->user, nr_slots, pipe->nr_accounted); |
Michael Kerrisk (man-pages) | b0b91d1 | 2016-10-11 13:53:31 -0700 | [diff] [blame] | 1365 | return ret; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1366 | } |
| 1367 | |
Jens Axboe | ff9da69 | 2010-06-03 14:54:39 +0200 | [diff] [blame] | 1368 | /* |
Christoph Hellwig | 4e7b567 | 2020-11-23 13:38:40 +0100 | [diff] [blame] | 1369 | * Note that i_pipe and i_cdev share the same location, so checking ->i_pipe is |
| 1370 | * not enough to verify that this is a pipe. |
Linus Torvalds | 7208364 | 2010-11-28 16:27:19 -0800 | [diff] [blame] | 1371 | */ |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1372 | struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice) |
Linus Torvalds | 7208364 | 2010-11-28 16:27:19 -0800 | [diff] [blame] | 1373 | { |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1374 | struct pipe_inode_info *pipe = file->private_data; |
| 1375 | |
| 1376 | if (file->f_op != &pipefifo_fops || !pipe) |
| 1377 | return NULL; |
| 1378 | #ifdef CONFIG_WATCH_QUEUE |
| 1379 | if (for_splice && pipe->watch_queue) |
| 1380 | return NULL; |
| 1381 | #endif |
| 1382 | return pipe; |
Linus Torvalds | 7208364 | 2010-11-28 16:27:19 -0800 | [diff] [blame] | 1383 | } |
| 1384 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1385 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
| 1386 | { |
| 1387 | struct pipe_inode_info *pipe; |
| 1388 | long ret; |
| 1389 | |
David Howells | c73be61 | 2020-01-14 17:07:11 +0000 | [diff] [blame] | 1390 | pipe = get_pipe_info(file, false); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1391 | if (!pipe) |
| 1392 | return -EBADF; |
| 1393 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1394 | __pipe_lock(pipe); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1395 | |
| 1396 | switch (cmd) { |
Michael Kerrisk (man-pages) | d37d416 | 2016-10-11 13:53:25 -0700 | [diff] [blame] | 1397 | case F_SETPIPE_SZ: |
| 1398 | ret = pipe_set_size(pipe, arg); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1399 | break; |
| 1400 | case F_GETPIPE_SZ: |
David Howells | 6718b6f | 2019-10-16 16:47:32 +0100 | [diff] [blame] | 1401 | ret = pipe->max_usage * PAGE_SIZE; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1402 | break; |
| 1403 | default: |
| 1404 | ret = -EINVAL; |
| 1405 | break; |
| 1406 | } |
| 1407 | |
Al Viro | ebec73f | 2013-03-21 12:24:01 -0400 | [diff] [blame] | 1408 | __pipe_unlock(pipe); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1409 | return ret; |
| 1410 | } |
| 1411 | |
Nick Piggin | ff0c7d1 | 2011-01-07 17:49:50 +1100 | [diff] [blame] | 1412 | static const struct super_operations pipefs_ops = { |
| 1413 | .destroy_inode = free_inode_nonrcu, |
Pavel Emelyanov | d70ef97 | 2011-10-31 17:10:04 -0700 | [diff] [blame] | 1414 | .statfs = simple_statfs, |
Nick Piggin | ff0c7d1 | 2011-01-07 17:49:50 +1100 | [diff] [blame] | 1415 | }; |
| 1416 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1417 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | * pipefs should _never_ be mounted by userland - too much of security hassle, |
| 1419 | * no real gain from having the whole whorehouse mounted. So we don't need |
| 1420 | * any operations on the root directory. However, we need a non-trivial |
| 1421 | * d_name - pipe: will go nicely and kill the special-casing in procfs. |
| 1422 | */ |
David Howells | 4fa7ec5 | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 1423 | |
| 1424 | static int pipefs_init_fs_context(struct fs_context *fc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1425 | { |
David Howells | 4fa7ec5 | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 1426 | struct pseudo_fs_context *ctx = init_pseudo(fc, PIPEFS_MAGIC); |
| 1427 | if (!ctx) |
| 1428 | return -ENOMEM; |
| 1429 | ctx->ops = &pipefs_ops; |
| 1430 | ctx->dops = &pipefs_dentry_operations; |
| 1431 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1432 | } |
| 1433 | |
| 1434 | static struct file_system_type pipe_fs_type = { |
| 1435 | .name = "pipefs", |
David Howells | 4fa7ec5 | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 1436 | .init_fs_context = pipefs_init_fs_context, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | .kill_sb = kill_anon_super, |
| 1438 | }; |
| 1439 | |
Luis Chamberlain | 1998f19 | 2022-01-21 22:13:20 -0800 | [diff] [blame] | 1440 | #ifdef CONFIG_SYSCTL |
| 1441 | static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, |
| 1442 | unsigned int *valp, |
| 1443 | int write, void *data) |
| 1444 | { |
| 1445 | if (write) { |
| 1446 | unsigned int val; |
| 1447 | |
| 1448 | val = round_pipe_size(*lvalp); |
| 1449 | if (val == 0) |
| 1450 | return -EINVAL; |
| 1451 | |
| 1452 | *valp = val; |
| 1453 | } else { |
| 1454 | unsigned int val = *valp; |
| 1455 | *lvalp = (unsigned long) val; |
| 1456 | } |
| 1457 | |
| 1458 | return 0; |
| 1459 | } |
| 1460 | |
| 1461 | static int proc_dopipe_max_size(struct ctl_table *table, int write, |
| 1462 | void *buffer, size_t *lenp, loff_t *ppos) |
| 1463 | { |
| 1464 | return do_proc_douintvec(table, write, buffer, lenp, ppos, |
| 1465 | do_proc_dopipe_max_size_conv, NULL); |
| 1466 | } |
| 1467 | |
| 1468 | static struct ctl_table fs_pipe_sysctls[] = { |
| 1469 | { |
| 1470 | .procname = "pipe-max-size", |
| 1471 | .data = &pipe_max_size, |
| 1472 | .maxlen = sizeof(pipe_max_size), |
| 1473 | .mode = 0644, |
| 1474 | .proc_handler = proc_dopipe_max_size, |
| 1475 | }, |
| 1476 | { |
| 1477 | .procname = "pipe-user-pages-hard", |
| 1478 | .data = &pipe_user_pages_hard, |
| 1479 | .maxlen = sizeof(pipe_user_pages_hard), |
| 1480 | .mode = 0644, |
| 1481 | .proc_handler = proc_doulongvec_minmax, |
| 1482 | }, |
| 1483 | { |
| 1484 | .procname = "pipe-user-pages-soft", |
| 1485 | .data = &pipe_user_pages_soft, |
| 1486 | .maxlen = sizeof(pipe_user_pages_soft), |
| 1487 | .mode = 0644, |
| 1488 | .proc_handler = proc_doulongvec_minmax, |
| 1489 | }, |
| 1490 | { } |
| 1491 | }; |
| 1492 | #endif |
| 1493 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1494 | static int __init init_pipe_fs(void) |
| 1495 | { |
| 1496 | int err = register_filesystem(&pipe_fs_type); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1497 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1498 | if (!err) { |
| 1499 | pipe_mnt = kern_mount(&pipe_fs_type); |
| 1500 | if (IS_ERR(pipe_mnt)) { |
| 1501 | err = PTR_ERR(pipe_mnt); |
| 1502 | unregister_filesystem(&pipe_fs_type); |
| 1503 | } |
| 1504 | } |
Luis Chamberlain | 1998f19 | 2022-01-21 22:13:20 -0800 | [diff] [blame] | 1505 | #ifdef CONFIG_SYSCTL |
| 1506 | register_sysctl_init("fs", fs_pipe_sysctls); |
| 1507 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1508 | return err; |
| 1509 | } |
| 1510 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1511 | fs_initcall(init_pipe_fs); |