Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/pipe.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1999 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | #include <linux/mm.h> |
| 8 | #include <linux/file.h> |
| 9 | #include <linux/poll.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/fs.h> |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 14 | #include <linux/log2.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/mount.h> |
| 16 | #include <linux/pipe_fs_i.h> |
| 17 | #include <linux/uio.h> |
| 18 | #include <linux/highmem.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 19 | #include <linux/pagemap.h> |
Al Viro | db34950 | 2007-02-07 01:48:00 -0500 | [diff] [blame] | 20 | #include <linux/audit.h> |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 21 | #include <linux/syscalls.h> |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 22 | #include <linux/fcntl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | |
| 24 | #include <asm/uaccess.h> |
| 25 | #include <asm/ioctls.h> |
| 26 | |
| 27 | /* |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 28 | * The max size that a non-root user is allowed to grow the pipe. Can |
| 29 | * be set by root in /proc/sys/fs/pipe-max-pages |
| 30 | */ |
| 31 | unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16; |
| 32 | |
| 33 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | * We use a start+len construction, which provides full use of the |
| 35 | * allocated memory. |
| 36 | * -- Florian Coosmann (FGC) |
| 37 | * |
| 38 | * Reads with count = 0 should always return 0. |
| 39 | * -- Julian Bradfield 1999-06-07. |
| 40 | * |
| 41 | * FIFOs and Pipes now generate SIGIO for both readers and writers. |
| 42 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 |
| 43 | * |
| 44 | * pipe_read & write cleanup |
| 45 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 |
| 46 | */ |
| 47 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 48 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
| 49 | { |
| 50 | if (pipe->inode) |
| 51 | mutex_lock_nested(&pipe->inode->i_mutex, subclass); |
| 52 | } |
| 53 | |
| 54 | void pipe_lock(struct pipe_inode_info *pipe) |
| 55 | { |
| 56 | /* |
| 57 | * pipe_lock() nests non-pipe inode locks (for writing to a file) |
| 58 | */ |
| 59 | pipe_lock_nested(pipe, I_MUTEX_PARENT); |
| 60 | } |
| 61 | EXPORT_SYMBOL(pipe_lock); |
| 62 | |
| 63 | void pipe_unlock(struct pipe_inode_info *pipe) |
| 64 | { |
| 65 | if (pipe->inode) |
| 66 | mutex_unlock(&pipe->inode->i_mutex); |
| 67 | } |
| 68 | EXPORT_SYMBOL(pipe_unlock); |
| 69 | |
| 70 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
| 71 | struct pipe_inode_info *pipe2) |
| 72 | { |
| 73 | BUG_ON(pipe1 == pipe2); |
| 74 | |
| 75 | if (pipe1 < pipe2) { |
| 76 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); |
| 77 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); |
| 78 | } else { |
Peter Zijlstra | 023d43c | 2009-07-21 10:09:23 +0200 | [diff] [blame] | 79 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
| 80 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 81 | } |
| 82 | } |
| 83 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 85 | void pipe_wait(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | { |
| 87 | DEFINE_WAIT(wait); |
| 88 | |
Ingo Molnar | d79fc0f | 2005-09-10 00:26:12 -0700 | [diff] [blame] | 89 | /* |
| 90 | * Pipes are system-local resources, so sleeping on them |
| 91 | * is considered a noninteractive wait: |
| 92 | */ |
Mike Galbraith | af92723 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 93 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 94 | pipe_unlock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | schedule(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 96 | finish_wait(&pipe->wait, &wait); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame] | 97 | pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | } |
| 99 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 100 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 101 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
| 102 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | { |
| 104 | unsigned long copy; |
| 105 | |
| 106 | while (len > 0) { |
| 107 | while (!iov->iov_len) |
| 108 | iov++; |
| 109 | copy = min_t(unsigned long, len, iov->iov_len); |
| 110 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 111 | if (atomic) { |
| 112 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) |
| 113 | return -EFAULT; |
| 114 | } else { |
| 115 | if (copy_from_user(to, iov->iov_base, copy)) |
| 116 | return -EFAULT; |
| 117 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | to += copy; |
| 119 | len -= copy; |
| 120 | iov->iov_base += copy; |
| 121 | iov->iov_len -= copy; |
| 122 | } |
| 123 | return 0; |
| 124 | } |
| 125 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 126 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 127 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
| 128 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | { |
| 130 | unsigned long copy; |
| 131 | |
| 132 | while (len > 0) { |
| 133 | while (!iov->iov_len) |
| 134 | iov++; |
| 135 | copy = min_t(unsigned long, len, iov->iov_len); |
| 136 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 137 | if (atomic) { |
| 138 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) |
| 139 | return -EFAULT; |
| 140 | } else { |
| 141 | if (copy_to_user(iov->iov_base, from, copy)) |
| 142 | return -EFAULT; |
| 143 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | from += copy; |
| 145 | len -= copy; |
| 146 | iov->iov_base += copy; |
| 147 | iov->iov_len -= copy; |
| 148 | } |
| 149 | return 0; |
| 150 | } |
| 151 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 152 | /* |
| 153 | * Attempt to pre-fault in the user memory, so we can use atomic copies. |
| 154 | * Returns the number of bytes not faulted in. |
| 155 | */ |
| 156 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) |
| 157 | { |
| 158 | while (!iov->iov_len) |
| 159 | iov++; |
| 160 | |
| 161 | while (len > 0) { |
| 162 | unsigned long this_len; |
| 163 | |
| 164 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 165 | if (fault_in_pages_writeable(iov->iov_base, this_len)) |
| 166 | break; |
| 167 | |
| 168 | len -= this_len; |
| 169 | iov++; |
| 170 | } |
| 171 | |
| 172 | return len; |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * Pre-fault in the user memory, so we can use atomic copies. |
| 177 | */ |
| 178 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) |
| 179 | { |
| 180 | while (!iov->iov_len) |
| 181 | iov++; |
| 182 | |
| 183 | while (len > 0) { |
| 184 | unsigned long this_len; |
| 185 | |
| 186 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 187 | fault_in_pages_readable(iov->iov_base, this_len); |
| 188 | len -= this_len; |
| 189 | iov++; |
| 190 | } |
| 191 | } |
| 192 | |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 193 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
| 194 | struct pipe_buffer *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | { |
| 196 | struct page *page = buf->page; |
| 197 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 198 | /* |
| 199 | * If nobody else uses this page, and we don't already have a |
| 200 | * temporary page, let's keep track of it as a one-deep |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 201 | * allocation cache. (Otherwise just release our reference to it) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 202 | */ |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 203 | if (page_count(page) == 1 && !pipe->tmp_page) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 204 | pipe->tmp_page = page; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 205 | else |
| 206 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | } |
| 208 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 209 | /** |
| 210 | * generic_pipe_buf_map - virtually map a pipe buffer |
| 211 | * @pipe: the pipe that the buffer belongs to |
| 212 | * @buf: the buffer that should be mapped |
| 213 | * @atomic: whether to use an atomic map |
| 214 | * |
| 215 | * Description: |
| 216 | * This function returns a kernel virtual address mapping for the |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 217 | * pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 218 | * and the caller has to be careful not to fault before calling |
| 219 | * the unmap function. |
| 220 | * |
| 221 | * Note that this function occupies KM_USER0 if @atomic != 0. |
| 222 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 223 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 224 | struct pipe_buffer *buf, int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 226 | if (atomic) { |
| 227 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; |
| 228 | return kmap_atomic(buf->page, KM_USER0); |
| 229 | } |
| 230 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | return kmap(buf->page); |
| 232 | } |
| 233 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 234 | /** |
| 235 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer |
| 236 | * @pipe: the pipe that the buffer belongs to |
| 237 | * @buf: the buffer that should be unmapped |
| 238 | * @map_data: the data that the mapping function returned |
| 239 | * |
| 240 | * Description: |
| 241 | * This function undoes the mapping that ->map() provided. |
| 242 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 243 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 244 | struct pipe_buffer *buf, void *map_data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 246 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
| 247 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; |
| 248 | kunmap_atomic(map_data, KM_USER0); |
| 249 | } else |
| 250 | kunmap(buf->page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | } |
| 252 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 253 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 254 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 255 | * @pipe: the pipe that the buffer belongs to |
| 256 | * @buf: the buffer to attempt to steal |
| 257 | * |
| 258 | * Description: |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 259 | * This function attempts to steal the &struct page attached to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 260 | * @buf. If successful, this function returns 0 and returns with |
| 261 | * the page locked. The caller may then reuse the page for whatever |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 262 | * he wishes; the typical use is insertion into a different file |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 263 | * page cache. |
| 264 | */ |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 265 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 266 | struct pipe_buffer *buf) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 267 | { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 268 | struct page *page = buf->page; |
| 269 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 270 | /* |
| 271 | * A reference of one is golden, that means that the owner of this |
| 272 | * page is the only one holding a reference to it. lock the page |
| 273 | * and return OK. |
| 274 | */ |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 275 | if (page_count(page) == 1) { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 276 | lock_page(page); |
| 277 | return 0; |
| 278 | } |
| 279 | |
| 280 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 281 | } |
| 282 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 283 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 284 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 285 | * @pipe: the pipe that the buffer belongs to |
| 286 | * @buf: the buffer to get a reference to |
| 287 | * |
| 288 | * Description: |
| 289 | * This function grabs an extra reference to @buf. It's used in |
| 290 | * in the tee() system call, when we duplicate the buffers in one |
| 291 | * pipe into another. |
| 292 | */ |
| 293 | void 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] | 294 | { |
| 295 | page_cache_get(buf->page); |
| 296 | } |
| 297 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 298 | /** |
| 299 | * generic_pipe_buf_confirm - verify contents of the pipe buffer |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 300 | * @info: the pipe that the buffer belongs to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 301 | * @buf: the buffer to confirm |
| 302 | * |
| 303 | * Description: |
| 304 | * This function does nothing, because the generic pipe code uses |
| 305 | * pages that are always good when inserted into the pipe. |
| 306 | */ |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 307 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
| 308 | struct pipe_buffer *buf) |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 309 | { |
| 310 | return 0; |
| 311 | } |
| 312 | |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 313 | /** |
| 314 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer |
| 315 | * @pipe: the pipe that the buffer belongs to |
| 316 | * @buf: the buffer to put a reference to |
| 317 | * |
| 318 | * Description: |
| 319 | * This function releases a reference to @buf. |
| 320 | */ |
| 321 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, |
| 322 | struct pipe_buffer *buf) |
| 323 | { |
| 324 | page_cache_release(buf->page); |
| 325 | } |
| 326 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 327 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | .can_merge = 1, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 329 | .map = generic_pipe_buf_map, |
| 330 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 331 | .confirm = generic_pipe_buf_confirm, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | .release = anon_pipe_buf_release, |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 333 | .steal = generic_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 334 | .get = generic_pipe_buf_get, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | }; |
| 336 | |
| 337 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 338 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
| 339 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 341 | struct file *filp = iocb->ki_filp; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 342 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 343 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | int do_wakeup; |
| 345 | ssize_t ret; |
| 346 | struct iovec *iov = (struct iovec *)_iov; |
| 347 | size_t total_len; |
| 348 | |
| 349 | total_len = iov_length(iov, nr_segs); |
| 350 | /* Null read succeeds. */ |
| 351 | if (unlikely(total_len == 0)) |
| 352 | return 0; |
| 353 | |
| 354 | do_wakeup = 0; |
| 355 | ret = 0; |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 356 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 357 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | for (;;) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 359 | int bufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | if (bufs) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 361 | int curbuf = pipe->curbuf; |
| 362 | struct pipe_buffer *buf = pipe->bufs + curbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 363 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | void *addr; |
| 365 | size_t chars = buf->len; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 366 | int error, atomic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | |
| 368 | if (chars > total_len) |
| 369 | chars = total_len; |
| 370 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 371 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 372 | if (error) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 373 | if (!ret) |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 374 | error = ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 375 | break; |
| 376 | } |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 377 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 378 | atomic = !iov_fault_in_pages_write(iov, chars); |
| 379 | redo: |
| 380 | addr = ops->map(pipe, buf, atomic); |
| 381 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); |
| 382 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 384 | /* |
| 385 | * Just retry with the slow path if we failed. |
| 386 | */ |
| 387 | if (atomic) { |
| 388 | atomic = 0; |
| 389 | goto redo; |
| 390 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 391 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 392 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | break; |
| 394 | } |
| 395 | ret += chars; |
| 396 | buf->offset += chars; |
| 397 | buf->len -= chars; |
| 398 | if (!buf->len) { |
| 399 | buf->ops = NULL; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 400 | ops->release(pipe, buf); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 401 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 402 | pipe->curbuf = curbuf; |
| 403 | pipe->nrbufs = --bufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | do_wakeup = 1; |
| 405 | } |
| 406 | total_len -= chars; |
| 407 | if (!total_len) |
| 408 | break; /* common path: read succeeded */ |
| 409 | } |
| 410 | if (bufs) /* More to do? */ |
| 411 | continue; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 412 | if (!pipe->writers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | break; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 414 | if (!pipe->waiting_writers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | /* syscall merging: Usually we must not sleep |
| 416 | * if O_NONBLOCK is set, or if we got some data. |
| 417 | * But if a writer sleeps in kernel space, then |
| 418 | * we can wait for that data without violating POSIX. |
| 419 | */ |
| 420 | if (ret) |
| 421 | break; |
| 422 | if (filp->f_flags & O_NONBLOCK) { |
| 423 | ret = -EAGAIN; |
| 424 | break; |
| 425 | } |
| 426 | } |
| 427 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 428 | if (!ret) |
| 429 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | break; |
| 431 | } |
| 432 | if (do_wakeup) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 433 | wake_up_interruptible_sync(&pipe->wait); |
| 434 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 436 | pipe_wait(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 438 | mutex_unlock(&inode->i_mutex); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 439 | |
| 440 | /* Signal writers asynchronously that there is more room. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | if (do_wakeup) { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 442 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 443 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | } |
| 445 | if (ret > 0) |
| 446 | file_accessed(filp); |
| 447 | return ret; |
| 448 | } |
| 449 | |
| 450 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 451 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
| 452 | unsigned long nr_segs, loff_t ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 454 | struct file *filp = iocb->ki_filp; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 455 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 456 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | ssize_t ret; |
| 458 | int do_wakeup; |
| 459 | struct iovec *iov = (struct iovec *)_iov; |
| 460 | size_t total_len; |
| 461 | ssize_t chars; |
| 462 | |
| 463 | total_len = iov_length(iov, nr_segs); |
| 464 | /* Null write succeeds. */ |
| 465 | if (unlikely(total_len == 0)) |
| 466 | return 0; |
| 467 | |
| 468 | do_wakeup = 0; |
| 469 | ret = 0; |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 470 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 471 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 473 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | send_sig(SIGPIPE, current, 0); |
| 475 | ret = -EPIPE; |
| 476 | goto out; |
| 477 | } |
| 478 | |
| 479 | /* We try to merge small writes */ |
| 480 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 481 | if (pipe->nrbufs && chars != 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 482 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 483 | (pipe->buffers - 1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 484 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 485 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | int offset = buf->offset + buf->len; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 487 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 489 | int error, atomic = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 490 | void *addr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 491 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 492 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 493 | if (error) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 494 | goto out; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 495 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 496 | iov_fault_in_pages_read(iov, chars); |
| 497 | redo1: |
| 498 | addr = ops->map(pipe, buf, atomic); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 499 | error = pipe_iov_copy_from_user(offset + addr, iov, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 500 | chars, atomic); |
| 501 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | ret = error; |
| 503 | do_wakeup = 1; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 504 | if (error) { |
| 505 | if (atomic) { |
| 506 | atomic = 0; |
| 507 | goto redo1; |
| 508 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | goto out; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 510 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | buf->len += chars; |
| 512 | total_len -= chars; |
| 513 | ret = chars; |
| 514 | if (!total_len) |
| 515 | goto out; |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | for (;;) { |
| 520 | int bufs; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 521 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 522 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | send_sig(SIGPIPE, current, 0); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 524 | if (!ret) |
| 525 | ret = -EPIPE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | break; |
| 527 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 528 | bufs = pipe->nrbufs; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 529 | if (bufs < pipe->buffers) { |
| 530 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 531 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
| 532 | struct page *page = pipe->tmp_page; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 533 | char *src; |
| 534 | int error, atomic = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | |
| 536 | if (!page) { |
| 537 | page = alloc_page(GFP_HIGHUSER); |
| 538 | if (unlikely(!page)) { |
| 539 | ret = ret ? : -ENOMEM; |
| 540 | break; |
| 541 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 542 | pipe->tmp_page = page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 544 | /* Always wake up, even if the copy fails. Otherwise |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | * we lock up (O_NONBLOCK-)readers that sleep due to |
| 546 | * syscall merging. |
| 547 | * FIXME! Is this really true? |
| 548 | */ |
| 549 | do_wakeup = 1; |
| 550 | chars = PAGE_SIZE; |
| 551 | if (chars > total_len) |
| 552 | chars = total_len; |
| 553 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 554 | iov_fault_in_pages_read(iov, chars); |
| 555 | redo2: |
| 556 | if (atomic) |
| 557 | src = kmap_atomic(page, KM_USER0); |
| 558 | else |
| 559 | src = kmap(page); |
| 560 | |
| 561 | error = pipe_iov_copy_from_user(src, iov, chars, |
| 562 | atomic); |
| 563 | if (atomic) |
| 564 | kunmap_atomic(src, KM_USER0); |
| 565 | else |
| 566 | kunmap(page); |
| 567 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 569 | if (atomic) { |
| 570 | atomic = 0; |
| 571 | goto redo2; |
| 572 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 573 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 574 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | break; |
| 576 | } |
| 577 | ret += chars; |
| 578 | |
| 579 | /* Insert it into the buffer array */ |
| 580 | buf->page = page; |
| 581 | buf->ops = &anon_pipe_buf_ops; |
| 582 | buf->offset = 0; |
| 583 | buf->len = chars; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 584 | pipe->nrbufs = ++bufs; |
| 585 | pipe->tmp_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 586 | |
| 587 | total_len -= chars; |
| 588 | if (!total_len) |
| 589 | break; |
| 590 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 591 | if (bufs < pipe->buffers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | continue; |
| 593 | if (filp->f_flags & O_NONBLOCK) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 594 | if (!ret) |
| 595 | ret = -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | break; |
| 597 | } |
| 598 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 599 | if (!ret) |
| 600 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | break; |
| 602 | } |
| 603 | if (do_wakeup) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 604 | wake_up_interruptible_sync(&pipe->wait); |
| 605 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | do_wakeup = 0; |
| 607 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 608 | pipe->waiting_writers++; |
| 609 | pipe_wait(pipe); |
| 610 | pipe->waiting_writers--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | } |
| 612 | out: |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 613 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | if (do_wakeup) { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 615 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 616 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | } |
| 618 | if (ret > 0) |
Christoph Hellwig | 870f481 | 2006-01-09 20:52:01 -0800 | [diff] [blame] | 619 | file_update_time(filp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | return ret; |
| 621 | } |
| 622 | |
| 623 | static ssize_t |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
| 625 | { |
| 626 | return -EBADF; |
| 627 | } |
| 628 | |
| 629 | static ssize_t |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 630 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
| 631 | loff_t *ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | { |
| 633 | return -EBADF; |
| 634 | } |
| 635 | |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 636 | 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] | 637 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 638 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 639 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | int count, buf, nrbufs; |
| 641 | |
| 642 | switch (cmd) { |
| 643 | case FIONREAD: |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 644 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 645 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | count = 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 647 | buf = pipe->curbuf; |
| 648 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | while (--nrbufs >= 0) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 650 | count += pipe->bufs[buf].len; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 651 | buf = (buf+1) & (pipe->buffers - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 653 | mutex_unlock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 654 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | return put_user(count, (int __user *)arg); |
| 656 | default: |
| 657 | return -EINVAL; |
| 658 | } |
| 659 | } |
| 660 | |
| 661 | /* No kernel lock held - fine */ |
| 662 | static unsigned int |
| 663 | pipe_poll(struct file *filp, poll_table *wait) |
| 664 | { |
| 665 | unsigned int mask; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 666 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 667 | struct pipe_inode_info *pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | int nrbufs; |
| 669 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 670 | poll_wait(filp, &pipe->wait, wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | |
| 672 | /* Reading only -- no need for acquiring the semaphore. */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 673 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 674 | mask = 0; |
| 675 | if (filp->f_mode & FMODE_READ) { |
| 676 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 677 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | mask |= POLLHUP; |
| 679 | } |
| 680 | |
| 681 | if (filp->f_mode & FMODE_WRITE) { |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 682 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 683 | /* |
| 684 | * Most Unices do not set POLLERR for FIFOs but on Linux they |
| 685 | * behave exactly like pipes for poll(). |
| 686 | */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 687 | if (!pipe->readers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | mask |= POLLERR; |
| 689 | } |
| 690 | |
| 691 | return mask; |
| 692 | } |
| 693 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | static int |
| 695 | pipe_release(struct inode *inode, int decr, int decw) |
| 696 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 697 | struct pipe_inode_info *pipe; |
| 698 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 699 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 700 | pipe = inode->i_pipe; |
| 701 | pipe->readers -= decr; |
| 702 | pipe->writers -= decw; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 703 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 704 | if (!pipe->readers && !pipe->writers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | free_pipe_info(inode); |
| 706 | } else { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 707 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 708 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 709 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 710 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 711 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | |
| 713 | return 0; |
| 714 | } |
| 715 | |
| 716 | static int |
| 717 | pipe_read_fasync(int fd, struct file *filp, int on) |
| 718 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 719 | struct inode *inode = filp->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | int retval; |
| 721 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 722 | mutex_lock(&inode->i_mutex); |
| 723 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); |
| 724 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 726 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | } |
| 728 | |
| 729 | |
| 730 | static int |
| 731 | pipe_write_fasync(int fd, struct file *filp, int on) |
| 732 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 733 | struct inode *inode = filp->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | int retval; |
| 735 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 736 | mutex_lock(&inode->i_mutex); |
| 737 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); |
| 738 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 739 | |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 740 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 741 | } |
| 742 | |
| 743 | |
| 744 | static int |
| 745 | pipe_rdwr_fasync(int fd, struct file *filp, int on) |
| 746 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 747 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 748 | struct pipe_inode_info *pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 749 | int retval; |
| 750 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 751 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 752 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 753 | if (retval >= 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 754 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 755 | if (retval < 0) /* this can happen only if on == T */ |
| 756 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
| 757 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 758 | mutex_unlock(&inode->i_mutex); |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 759 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 760 | } |
| 761 | |
| 762 | |
| 763 | static int |
| 764 | pipe_read_release(struct inode *inode, struct file *filp) |
| 765 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | return pipe_release(inode, 1, 0); |
| 767 | } |
| 768 | |
| 769 | static int |
| 770 | pipe_write_release(struct inode *inode, struct file *filp) |
| 771 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | return pipe_release(inode, 0, 1); |
| 773 | } |
| 774 | |
| 775 | static int |
| 776 | pipe_rdwr_release(struct inode *inode, struct file *filp) |
| 777 | { |
| 778 | int decr, decw; |
| 779 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 780 | decr = (filp->f_mode & FMODE_READ) != 0; |
| 781 | decw = (filp->f_mode & FMODE_WRITE) != 0; |
| 782 | return pipe_release(inode, decr, decw); |
| 783 | } |
| 784 | |
| 785 | static int |
| 786 | pipe_read_open(struct inode *inode, struct file *filp) |
| 787 | { |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 788 | int ret = -ENOENT; |
| 789 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 790 | mutex_lock(&inode->i_mutex); |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 791 | |
| 792 | if (inode->i_pipe) { |
| 793 | ret = 0; |
| 794 | inode->i_pipe->readers++; |
| 795 | } |
| 796 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 797 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 799 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | } |
| 801 | |
| 802 | static int |
| 803 | pipe_write_open(struct inode *inode, struct file *filp) |
| 804 | { |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 805 | int ret = -ENOENT; |
| 806 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 807 | mutex_lock(&inode->i_mutex); |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 808 | |
| 809 | if (inode->i_pipe) { |
| 810 | ret = 0; |
| 811 | inode->i_pipe->writers++; |
| 812 | } |
| 813 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 814 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 816 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | } |
| 818 | |
| 819 | static int |
| 820 | pipe_rdwr_open(struct inode *inode, struct file *filp) |
| 821 | { |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 822 | int ret = -ENOENT; |
| 823 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 824 | mutex_lock(&inode->i_mutex); |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 825 | |
| 826 | if (inode->i_pipe) { |
| 827 | ret = 0; |
| 828 | if (filp->f_mode & FMODE_READ) |
| 829 | inode->i_pipe->readers++; |
| 830 | if (filp->f_mode & FMODE_WRITE) |
| 831 | inode->i_pipe->writers++; |
| 832 | } |
| 833 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 834 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 835 | |
Earl Chew | ad39602 | 2009-10-19 15:55:41 -0700 | [diff] [blame] | 836 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | } |
| 838 | |
| 839 | /* |
| 840 | * The file_operations structs are not static because they |
| 841 | * are also used in linux/fs/fifo.c to do operations on FIFOs. |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 842 | * |
| 843 | * Pipes reuse fifos' file_operations structs. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | */ |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 845 | const struct file_operations read_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | .llseek = no_llseek, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 847 | .read = do_sync_read, |
| 848 | .aio_read = pipe_read, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 849 | .write = bad_pipe_w, |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 850 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 851 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | .open = pipe_read_open, |
| 853 | .release = pipe_read_release, |
| 854 | .fasync = pipe_read_fasync, |
| 855 | }; |
| 856 | |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 857 | const struct file_operations write_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | .llseek = no_llseek, |
| 859 | .read = bad_pipe_r, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 860 | .write = do_sync_write, |
| 861 | .aio_write = pipe_write, |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 862 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 863 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | .open = pipe_write_open, |
| 865 | .release = pipe_write_release, |
| 866 | .fasync = pipe_write_fasync, |
| 867 | }; |
| 868 | |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 869 | const struct file_operations rdwr_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | .llseek = no_llseek, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 871 | .read = do_sync_read, |
| 872 | .aio_read = pipe_read, |
| 873 | .write = do_sync_write, |
| 874 | .aio_write = pipe_write, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 876 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 877 | .open = pipe_rdwr_open, |
| 878 | .release = pipe_rdwr_release, |
| 879 | .fasync = pipe_rdwr_fasync, |
| 880 | }; |
| 881 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 882 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
| 883 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 884 | struct pipe_inode_info *pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 885 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 886 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
| 887 | if (pipe) { |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 888 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
| 889 | if (pipe->bufs) { |
| 890 | init_waitqueue_head(&pipe->wait); |
| 891 | pipe->r_counter = pipe->w_counter = 1; |
| 892 | pipe->inode = inode; |
| 893 | pipe->buffers = PIPE_DEF_BUFFERS; |
| 894 | return pipe; |
| 895 | } |
| 896 | kfree(pipe); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 897 | } |
| 898 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 899 | return NULL; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 900 | } |
| 901 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 902 | void __free_pipe_info(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | { |
| 904 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 905 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 906 | for (i = 0; i < pipe->buffers; i++) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 907 | struct pipe_buffer *buf = pipe->bufs + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | if (buf->ops) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 909 | buf->ops->release(pipe, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 911 | if (pipe->tmp_page) |
| 912 | __free_page(pipe->tmp_page); |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 913 | kfree(pipe->bufs); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 914 | kfree(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | } |
| 916 | |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 917 | void free_pipe_info(struct inode *inode) |
| 918 | { |
| 919 | __free_pipe_info(inode->i_pipe); |
| 920 | inode->i_pipe = NULL; |
| 921 | } |
| 922 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 923 | static struct vfsmount *pipe_mnt __read_mostly; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 924 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 925 | /* |
| 926 | * pipefs_dname() is called from d_path(). |
| 927 | */ |
| 928 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) |
| 929 | { |
| 930 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", |
| 931 | dentry->d_inode->i_ino); |
| 932 | } |
| 933 | |
Al Viro | 3ba13d1 | 2009-02-20 06:02:22 +0000 | [diff] [blame] | 934 | static const struct dentry_operations pipefs_dentry_operations = { |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 935 | .d_dname = pipefs_dname, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | }; |
| 937 | |
| 938 | static struct inode * get_pipe_inode(void) |
| 939 | { |
| 940 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 941 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 942 | |
| 943 | if (!inode) |
| 944 | goto fail_inode; |
| 945 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 946 | pipe = alloc_pipe_info(inode); |
| 947 | if (!pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 948 | goto fail_iput; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 949 | inode->i_pipe = pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 950 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 951 | pipe->readers = pipe->writers = 1; |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 952 | inode->i_fop = &rdwr_pipefifo_fops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 953 | |
| 954 | /* |
| 955 | * Mark the inode dirty from the very beginning, |
| 956 | * that way it will never be moved to the dirty |
| 957 | * list because "mark_inode_dirty()" will think |
| 958 | * that it already _is_ on the dirty list. |
| 959 | */ |
| 960 | inode->i_state = I_DIRTY; |
| 961 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 962 | inode->i_uid = current_fsuid(); |
| 963 | inode->i_gid = current_fsgid(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 965 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | return inode; |
| 967 | |
| 968 | fail_iput: |
| 969 | iput(inode); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 970 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | fail_inode: |
| 972 | return NULL; |
| 973 | } |
| 974 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 975 | struct file *create_write_pipe(int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | { |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 977 | int err; |
| 978 | struct inode *inode; |
| 979 | struct file *f; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 980 | struct path path; |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 981 | struct qstr name = { .name = "" }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 982 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 983 | err = -ENFILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 984 | inode = get_pipe_inode(); |
| 985 | if (!inode) |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 986 | goto err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 988 | err = -ENOMEM; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 989 | path.dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); |
| 990 | if (!path.dentry) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 991 | goto err_inode; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 992 | path.mnt = mntget(pipe_mnt); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 993 | |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 994 | path.dentry->d_op = &pipefs_dentry_operations; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 995 | d_instantiate(path.dentry, inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 996 | |
| 997 | err = -ENFILE; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 998 | f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 999 | if (!f) |
| 1000 | goto err_dentry; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1001 | f->f_mapping = inode->i_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1002 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1003 | f->f_flags = O_WRONLY | (flags & O_NONBLOCK); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1004 | f->f_version = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1005 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1006 | return f; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 1008 | err_dentry: |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 1009 | free_pipe_info(inode); |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 1010 | path_put(&path); |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 1011 | return ERR_PTR(err); |
| 1012 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1013 | err_inode: |
| 1014 | free_pipe_info(inode); |
| 1015 | iput(inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 1016 | err: |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1017 | return ERR_PTR(err); |
| 1018 | } |
| 1019 | |
| 1020 | void free_write_pipe(struct file *f) |
| 1021 | { |
Al Viro | 5ccac88e | 2006-12-18 13:31:18 +0000 | [diff] [blame] | 1022 | free_pipe_info(f->f_dentry->d_inode); |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1023 | path_put(&f->f_path); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1024 | put_filp(f); |
| 1025 | } |
| 1026 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1027 | struct file *create_read_pipe(struct file *wrf, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1028 | { |
Al Viro | d231412 | 2009-08-09 01:01:37 +0400 | [diff] [blame] | 1029 | /* Grab pipe from the writer */ |
| 1030 | struct file *f = alloc_file(&wrf->f_path, FMODE_READ, |
| 1031 | &read_pipefifo_fops); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1032 | if (!f) |
| 1033 | return ERR_PTR(-ENFILE); |
| 1034 | |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1035 | path_get(&wrf->f_path); |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1036 | f->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1037 | |
| 1038 | return f; |
| 1039 | } |
| 1040 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1041 | int do_pipe_flags(int *fd, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1042 | { |
| 1043 | struct file *fw, *fr; |
| 1044 | int error; |
| 1045 | int fdw, fdr; |
| 1046 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1047 | if (flags & ~(O_CLOEXEC | O_NONBLOCK)) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1048 | return -EINVAL; |
| 1049 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1050 | fw = create_write_pipe(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1051 | if (IS_ERR(fw)) |
| 1052 | return PTR_ERR(fw); |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1053 | fr = create_read_pipe(fw, flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1054 | error = PTR_ERR(fr); |
| 1055 | if (IS_ERR(fr)) |
| 1056 | goto err_write_pipe; |
| 1057 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1058 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1059 | if (error < 0) |
| 1060 | goto err_read_pipe; |
| 1061 | fdr = error; |
| 1062 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1063 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1064 | if (error < 0) |
| 1065 | goto err_fdr; |
| 1066 | fdw = error; |
| 1067 | |
Al Viro | 157cf64 | 2008-12-14 04:57:47 -0500 | [diff] [blame] | 1068 | audit_fd_pair(fdr, fdw); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1069 | fd_install(fdr, fr); |
| 1070 | fd_install(fdw, fw); |
| 1071 | fd[0] = fdr; |
| 1072 | fd[1] = fdw; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1073 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1074 | return 0; |
| 1075 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1076 | err_fdr: |
| 1077 | put_unused_fd(fdr); |
| 1078 | err_read_pipe: |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1079 | path_put(&fr->f_path); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1080 | put_filp(fr); |
| 1081 | err_write_pipe: |
| 1082 | free_write_pipe(fw); |
| 1083 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | } |
| 1085 | |
| 1086 | /* |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1087 | * sys_pipe() is the normal C calling standard for creating |
| 1088 | * a pipe. It's not the way Unix traditionally does this, though. |
| 1089 | */ |
Heiko Carstens | d4e8204 | 2009-01-14 14:14:34 +0100 | [diff] [blame] | 1090 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1091 | { |
| 1092 | int fd[2]; |
| 1093 | int error; |
| 1094 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1095 | error = do_pipe_flags(fd, flags); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1096 | if (!error) { |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 1097 | if (copy_to_user(fildes, fd, sizeof(fd))) { |
| 1098 | sys_close(fd[0]); |
| 1099 | sys_close(fd[1]); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1100 | error = -EFAULT; |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 1101 | } |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1102 | } |
| 1103 | return error; |
| 1104 | } |
| 1105 | |
Heiko Carstens | 2b66421 | 2009-01-14 14:14:35 +0100 | [diff] [blame] | 1106 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1107 | { |
| 1108 | return sys_pipe2(fildes, 0); |
| 1109 | } |
| 1110 | |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1111 | /* |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1112 | * Allocate a new array of pipe buffers and copy the info over. Returns the |
| 1113 | * pipe size if successful, or return -ERROR on error. |
| 1114 | */ |
| 1115 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) |
| 1116 | { |
| 1117 | struct pipe_buffer *bufs; |
| 1118 | |
| 1119 | /* |
| 1120 | * Must be a power-of-2 currently |
| 1121 | */ |
| 1122 | if (!is_power_of_2(arg)) |
| 1123 | return -EINVAL; |
| 1124 | |
| 1125 | /* |
| 1126 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't |
| 1127 | * expect a lot of shrink+grow operations, just free and allocate |
| 1128 | * again like we would do for growing. If the pipe currently |
| 1129 | * contains more buffers than arg, then return busy. |
| 1130 | */ |
| 1131 | if (arg < pipe->nrbufs) |
| 1132 | return -EBUSY; |
| 1133 | |
| 1134 | bufs = kcalloc(arg, sizeof(struct pipe_buffer), GFP_KERNEL); |
| 1135 | if (unlikely(!bufs)) |
| 1136 | return -ENOMEM; |
| 1137 | |
| 1138 | /* |
| 1139 | * The pipe array wraps around, so just start the new one at zero |
| 1140 | * and adjust the indexes. |
| 1141 | */ |
| 1142 | if (pipe->nrbufs) { |
| 1143 | const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); |
| 1144 | const unsigned int head = pipe->nrbufs - tail; |
| 1145 | |
| 1146 | if (head) |
| 1147 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); |
| 1148 | if (tail) |
| 1149 | memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); |
| 1150 | } |
| 1151 | |
| 1152 | pipe->curbuf = 0; |
| 1153 | kfree(pipe->bufs); |
| 1154 | pipe->bufs = bufs; |
| 1155 | pipe->buffers = arg; |
| 1156 | return arg; |
| 1157 | } |
| 1158 | |
| 1159 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
| 1160 | { |
| 1161 | struct pipe_inode_info *pipe; |
| 1162 | long ret; |
| 1163 | |
| 1164 | pipe = file->f_path.dentry->d_inode->i_pipe; |
| 1165 | if (!pipe) |
| 1166 | return -EBADF; |
| 1167 | |
| 1168 | mutex_lock(&pipe->inode->i_mutex); |
| 1169 | |
| 1170 | switch (cmd) { |
| 1171 | case F_SETPIPE_SZ: |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame^] | 1172 | if (!capable(CAP_SYS_ADMIN) && arg > pipe_max_pages) { |
| 1173 | ret = -EINVAL; |
| 1174 | goto out; |
| 1175 | } |
Jens Axboe | b492e95 | 2010-05-19 21:03:16 +0200 | [diff] [blame] | 1176 | /* |
| 1177 | * The pipe needs to be at least 2 pages large to |
| 1178 | * guarantee POSIX behaviour. |
| 1179 | */ |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame^] | 1180 | if (arg < 2) { |
| 1181 | ret = -EINVAL; |
| 1182 | goto out; |
| 1183 | } |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1184 | ret = pipe_set_size(pipe, arg); |
| 1185 | break; |
| 1186 | case F_GETPIPE_SZ: |
| 1187 | ret = pipe->buffers; |
| 1188 | break; |
| 1189 | default: |
| 1190 | ret = -EINVAL; |
| 1191 | break; |
| 1192 | } |
| 1193 | |
Julia Lawall | cc967be | 2010-05-26 17:54:39 +0200 | [diff] [blame^] | 1194 | out: |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1195 | mutex_unlock(&pipe->inode->i_mutex); |
| 1196 | return ret; |
| 1197 | } |
| 1198 | |
| 1199 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | * pipefs should _never_ be mounted by userland - too much of security hassle, |
| 1201 | * no real gain from having the whole whorehouse mounted. So we don't need |
| 1202 | * any operations on the root directory. However, we need a non-trivial |
| 1203 | * d_name - pipe: will go nicely and kill the special-casing in procfs. |
| 1204 | */ |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1205 | static int pipefs_get_sb(struct file_system_type *fs_type, |
| 1206 | int flags, const char *dev_name, void *data, |
| 1207 | struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1208 | { |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1209 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1210 | } |
| 1211 | |
| 1212 | static struct file_system_type pipe_fs_type = { |
| 1213 | .name = "pipefs", |
| 1214 | .get_sb = pipefs_get_sb, |
| 1215 | .kill_sb = kill_anon_super, |
| 1216 | }; |
| 1217 | |
| 1218 | static int __init init_pipe_fs(void) |
| 1219 | { |
| 1220 | int err = register_filesystem(&pipe_fs_type); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1221 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1222 | if (!err) { |
| 1223 | pipe_mnt = kern_mount(&pipe_fs_type); |
| 1224 | if (IS_ERR(pipe_mnt)) { |
| 1225 | err = PTR_ERR(pipe_mnt); |
| 1226 | unregister_filesystem(&pipe_fs_type); |
| 1227 | } |
| 1228 | } |
| 1229 | return err; |
| 1230 | } |
| 1231 | |
| 1232 | static void __exit exit_pipe_fs(void) |
| 1233 | { |
| 1234 | unregister_filesystem(&pipe_fs_type); |
| 1235 | mntput(pipe_mnt); |
| 1236 | } |
| 1237 | |
| 1238 | fs_initcall(init_pipe_fs); |
| 1239 | module_exit(exit_pipe_fs); |