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> |
| 14 | #include <linux/mount.h> |
| 15 | #include <linux/pipe_fs_i.h> |
| 16 | #include <linux/uio.h> |
| 17 | #include <linux/highmem.h> |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 18 | #include <linux/pagemap.h> |
Al Viro | db34950 | 2007-02-07 01:48:00 -0500 | [diff] [blame] | 19 | #include <linux/audit.h> |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 20 | #include <linux/syscalls.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
| 22 | #include <asm/uaccess.h> |
| 23 | #include <asm/ioctls.h> |
| 24 | |
| 25 | /* |
| 26 | * We use a start+len construction, which provides full use of the |
| 27 | * allocated memory. |
| 28 | * -- Florian Coosmann (FGC) |
| 29 | * |
| 30 | * Reads with count = 0 should always return 0. |
| 31 | * -- Julian Bradfield 1999-06-07. |
| 32 | * |
| 33 | * FIFOs and Pipes now generate SIGIO for both readers and writers. |
| 34 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 |
| 35 | * |
| 36 | * pipe_read & write cleanup |
| 37 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 |
| 38 | */ |
| 39 | |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 40 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
| 41 | { |
| 42 | if (pipe->inode) |
| 43 | mutex_lock_nested(&pipe->inode->i_mutex, subclass); |
| 44 | } |
| 45 | |
| 46 | void pipe_lock(struct pipe_inode_info *pipe) |
| 47 | { |
| 48 | /* |
| 49 | * pipe_lock() nests non-pipe inode locks (for writing to a file) |
| 50 | */ |
| 51 | pipe_lock_nested(pipe, I_MUTEX_PARENT); |
| 52 | } |
| 53 | EXPORT_SYMBOL(pipe_lock); |
| 54 | |
| 55 | void pipe_unlock(struct pipe_inode_info *pipe) |
| 56 | { |
| 57 | if (pipe->inode) |
| 58 | mutex_unlock(&pipe->inode->i_mutex); |
| 59 | } |
| 60 | EXPORT_SYMBOL(pipe_unlock); |
| 61 | |
| 62 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
| 63 | struct pipe_inode_info *pipe2) |
| 64 | { |
| 65 | BUG_ON(pipe1 == pipe2); |
| 66 | |
| 67 | if (pipe1 < pipe2) { |
| 68 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); |
| 69 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); |
| 70 | } else { |
| 71 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); |
| 72 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); |
| 73 | } |
| 74 | } |
| 75 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 77 | void pipe_wait(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | { |
| 79 | DEFINE_WAIT(wait); |
| 80 | |
Ingo Molnar | d79fc0f | 2005-09-10 00:26:12 -0700 | [diff] [blame] | 81 | /* |
| 82 | * Pipes are system-local resources, so sleeping on them |
| 83 | * is considered a noninteractive wait: |
| 84 | */ |
Mike Galbraith | af92723 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 85 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 86 | pipe_unlock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | schedule(); |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 88 | finish_wait(&pipe->wait, &wait); |
Miklos Szeredi | 61e0d47 | 2009-04-14 19:48:41 +0200 | [diff] [blame^] | 89 | pipe_lock(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | } |
| 91 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 92 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 93 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
| 94 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | { |
| 96 | unsigned long copy; |
| 97 | |
| 98 | while (len > 0) { |
| 99 | while (!iov->iov_len) |
| 100 | iov++; |
| 101 | copy = min_t(unsigned long, len, iov->iov_len); |
| 102 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 103 | if (atomic) { |
| 104 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) |
| 105 | return -EFAULT; |
| 106 | } else { |
| 107 | if (copy_from_user(to, iov->iov_base, copy)) |
| 108 | return -EFAULT; |
| 109 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | to += copy; |
| 111 | len -= copy; |
| 112 | iov->iov_base += copy; |
| 113 | iov->iov_len -= copy; |
| 114 | } |
| 115 | return 0; |
| 116 | } |
| 117 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 118 | static int |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 119 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
| 120 | int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | { |
| 122 | unsigned long copy; |
| 123 | |
| 124 | while (len > 0) { |
| 125 | while (!iov->iov_len) |
| 126 | iov++; |
| 127 | copy = min_t(unsigned long, len, iov->iov_len); |
| 128 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 129 | if (atomic) { |
| 130 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) |
| 131 | return -EFAULT; |
| 132 | } else { |
| 133 | if (copy_to_user(iov->iov_base, from, copy)) |
| 134 | return -EFAULT; |
| 135 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | from += copy; |
| 137 | len -= copy; |
| 138 | iov->iov_base += copy; |
| 139 | iov->iov_len -= copy; |
| 140 | } |
| 141 | return 0; |
| 142 | } |
| 143 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 144 | /* |
| 145 | * Attempt to pre-fault in the user memory, so we can use atomic copies. |
| 146 | * Returns the number of bytes not faulted in. |
| 147 | */ |
| 148 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) |
| 149 | { |
| 150 | while (!iov->iov_len) |
| 151 | iov++; |
| 152 | |
| 153 | while (len > 0) { |
| 154 | unsigned long this_len; |
| 155 | |
| 156 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 157 | if (fault_in_pages_writeable(iov->iov_base, this_len)) |
| 158 | break; |
| 159 | |
| 160 | len -= this_len; |
| 161 | iov++; |
| 162 | } |
| 163 | |
| 164 | return len; |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Pre-fault in the user memory, so we can use atomic copies. |
| 169 | */ |
| 170 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) |
| 171 | { |
| 172 | while (!iov->iov_len) |
| 173 | iov++; |
| 174 | |
| 175 | while (len > 0) { |
| 176 | unsigned long this_len; |
| 177 | |
| 178 | this_len = min_t(unsigned long, len, iov->iov_len); |
| 179 | fault_in_pages_readable(iov->iov_base, this_len); |
| 180 | len -= this_len; |
| 181 | iov++; |
| 182 | } |
| 183 | } |
| 184 | |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 185 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
| 186 | struct pipe_buffer *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | { |
| 188 | struct page *page = buf->page; |
| 189 | |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 190 | /* |
| 191 | * If nobody else uses this page, and we don't already have a |
| 192 | * temporary page, let's keep track of it as a one-deep |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 193 | * allocation cache. (Otherwise just release our reference to it) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 194 | */ |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 195 | if (page_count(page) == 1 && !pipe->tmp_page) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 196 | pipe->tmp_page = page; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 197 | else |
| 198 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | } |
| 200 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 201 | /** |
| 202 | * generic_pipe_buf_map - virtually map a pipe buffer |
| 203 | * @pipe: the pipe that the buffer belongs to |
| 204 | * @buf: the buffer that should be mapped |
| 205 | * @atomic: whether to use an atomic map |
| 206 | * |
| 207 | * Description: |
| 208 | * This function returns a kernel virtual address mapping for the |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 209 | * 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] | 210 | * and the caller has to be careful not to fault before calling |
| 211 | * the unmap function. |
| 212 | * |
| 213 | * Note that this function occupies KM_USER0 if @atomic != 0. |
| 214 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 215 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 216 | struct pipe_buffer *buf, int atomic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 218 | if (atomic) { |
| 219 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; |
| 220 | return kmap_atomic(buf->page, KM_USER0); |
| 221 | } |
| 222 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | return kmap(buf->page); |
| 224 | } |
| 225 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 226 | /** |
| 227 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer |
| 228 | * @pipe: the pipe that the buffer belongs to |
| 229 | * @buf: the buffer that should be unmapped |
| 230 | * @map_data: the data that the mapping function returned |
| 231 | * |
| 232 | * Description: |
| 233 | * This function undoes the mapping that ->map() provided. |
| 234 | */ |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 235 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 236 | struct pipe_buffer *buf, void *map_data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 238 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
| 239 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; |
| 240 | kunmap_atomic(map_data, KM_USER0); |
| 241 | } else |
| 242 | kunmap(buf->page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | } |
| 244 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 245 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 246 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 247 | * @pipe: the pipe that the buffer belongs to |
| 248 | * @buf: the buffer to attempt to steal |
| 249 | * |
| 250 | * Description: |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 251 | * This function attempts to steal the &struct page attached to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 252 | * @buf. If successful, this function returns 0 and returns with |
| 253 | * the page locked. The caller may then reuse the page for whatever |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 254 | * he wishes; the typical use is insertion into a different file |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 255 | * page cache. |
| 256 | */ |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 257 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
| 258 | struct pipe_buffer *buf) |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 259 | { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 260 | struct page *page = buf->page; |
| 261 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 262 | /* |
| 263 | * A reference of one is golden, that means that the owner of this |
| 264 | * page is the only one holding a reference to it. lock the page |
| 265 | * and return OK. |
| 266 | */ |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 267 | if (page_count(page) == 1) { |
Jens Axboe | 46e678c | 2006-04-30 16:36:32 +0200 | [diff] [blame] | 268 | lock_page(page); |
| 269 | return 0; |
| 270 | } |
| 271 | |
| 272 | return 1; |
Jens Axboe | 5abc97a | 2006-03-30 15:16:46 +0200 | [diff] [blame] | 273 | } |
| 274 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 275 | /** |
Randy Dunlap | b51d63c | 2008-02-13 15:03:22 -0800 | [diff] [blame] | 276 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 277 | * @pipe: the pipe that the buffer belongs to |
| 278 | * @buf: the buffer to get a reference to |
| 279 | * |
| 280 | * Description: |
| 281 | * This function grabs an extra reference to @buf. It's used in |
| 282 | * in the tee() system call, when we duplicate the buffers in one |
| 283 | * pipe into another. |
| 284 | */ |
| 285 | 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] | 286 | { |
| 287 | page_cache_get(buf->page); |
| 288 | } |
| 289 | |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 290 | /** |
| 291 | * generic_pipe_buf_confirm - verify contents of the pipe buffer |
Randy Dunlap | 79685b8 | 2007-07-27 08:08:51 +0200 | [diff] [blame] | 292 | * @info: the pipe that the buffer belongs to |
Jens Axboe | 0845718 | 2007-06-12 20:51:32 +0200 | [diff] [blame] | 293 | * @buf: the buffer to confirm |
| 294 | * |
| 295 | * Description: |
| 296 | * This function does nothing, because the generic pipe code uses |
| 297 | * pages that are always good when inserted into the pipe. |
| 298 | */ |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 299 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
| 300 | struct pipe_buffer *buf) |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 301 | { |
| 302 | return 0; |
| 303 | } |
| 304 | |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 305 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | .can_merge = 1, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 307 | .map = generic_pipe_buf_map, |
| 308 | .unmap = generic_pipe_buf_unmap, |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 309 | .confirm = generic_pipe_buf_confirm, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | .release = anon_pipe_buf_release, |
Jens Axboe | 330ab71 | 2006-05-02 15:29:57 +0200 | [diff] [blame] | 311 | .steal = generic_pipe_buf_steal, |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 312 | .get = generic_pipe_buf_get, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | }; |
| 314 | |
| 315 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 316 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
| 317 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 319 | struct file *filp = iocb->ki_filp; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 320 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 321 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | int do_wakeup; |
| 323 | ssize_t ret; |
| 324 | struct iovec *iov = (struct iovec *)_iov; |
| 325 | size_t total_len; |
| 326 | |
| 327 | total_len = iov_length(iov, nr_segs); |
| 328 | /* Null read succeeds. */ |
| 329 | if (unlikely(total_len == 0)) |
| 330 | return 0; |
| 331 | |
| 332 | do_wakeup = 0; |
| 333 | ret = 0; |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 334 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 335 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | for (;;) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 337 | int bufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | if (bufs) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 339 | int curbuf = pipe->curbuf; |
| 340 | struct pipe_buffer *buf = pipe->bufs + curbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 341 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | void *addr; |
| 343 | size_t chars = buf->len; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 344 | int error, atomic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | |
| 346 | if (chars > total_len) |
| 347 | chars = total_len; |
| 348 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 349 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 350 | if (error) { |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 351 | if (!ret) |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 352 | error = ret; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 353 | break; |
| 354 | } |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 355 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 356 | atomic = !iov_fault_in_pages_write(iov, chars); |
| 357 | redo: |
| 358 | addr = ops->map(pipe, buf, atomic); |
| 359 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); |
| 360 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 362 | /* |
| 363 | * Just retry with the slow path if we failed. |
| 364 | */ |
| 365 | if (atomic) { |
| 366 | atomic = 0; |
| 367 | goto redo; |
| 368 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 369 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 370 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | break; |
| 372 | } |
| 373 | ret += chars; |
| 374 | buf->offset += chars; |
| 375 | buf->len -= chars; |
| 376 | if (!buf->len) { |
| 377 | buf->ops = NULL; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 378 | ops->release(pipe, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 380 | pipe->curbuf = curbuf; |
| 381 | pipe->nrbufs = --bufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | do_wakeup = 1; |
| 383 | } |
| 384 | total_len -= chars; |
| 385 | if (!total_len) |
| 386 | break; /* common path: read succeeded */ |
| 387 | } |
| 388 | if (bufs) /* More to do? */ |
| 389 | continue; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 390 | if (!pipe->writers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 391 | break; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 392 | if (!pipe->waiting_writers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | /* syscall merging: Usually we must not sleep |
| 394 | * if O_NONBLOCK is set, or if we got some data. |
| 395 | * But if a writer sleeps in kernel space, then |
| 396 | * we can wait for that data without violating POSIX. |
| 397 | */ |
| 398 | if (ret) |
| 399 | break; |
| 400 | if (filp->f_flags & O_NONBLOCK) { |
| 401 | ret = -EAGAIN; |
| 402 | break; |
| 403 | } |
| 404 | } |
| 405 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 406 | if (!ret) |
| 407 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | break; |
| 409 | } |
| 410 | if (do_wakeup) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 411 | wake_up_interruptible_sync(&pipe->wait); |
| 412 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 414 | pipe_wait(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 416 | mutex_unlock(&inode->i_mutex); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 417 | |
| 418 | /* Signal writers asynchronously that there is more room. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | if (do_wakeup) { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 420 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 421 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | } |
| 423 | if (ret > 0) |
| 424 | file_accessed(filp); |
| 425 | return ret; |
| 426 | } |
| 427 | |
| 428 | static ssize_t |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 429 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
| 430 | unsigned long nr_segs, loff_t ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | { |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 432 | struct file *filp = iocb->ki_filp; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 433 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 434 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | ssize_t ret; |
| 436 | int do_wakeup; |
| 437 | struct iovec *iov = (struct iovec *)_iov; |
| 438 | size_t total_len; |
| 439 | ssize_t chars; |
| 440 | |
| 441 | total_len = iov_length(iov, nr_segs); |
| 442 | /* Null write succeeds. */ |
| 443 | if (unlikely(total_len == 0)) |
| 444 | return 0; |
| 445 | |
| 446 | do_wakeup = 0; |
| 447 | ret = 0; |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 448 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 449 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 451 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | send_sig(SIGPIPE, current, 0); |
| 453 | ret = -EPIPE; |
| 454 | goto out; |
| 455 | } |
| 456 | |
| 457 | /* We try to merge small writes */ |
| 458 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 459 | if (pipe->nrbufs && chars != 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 460 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
| 461 | (PIPE_BUFFERS-1); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 462 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
Eric Dumazet | d4c3cca | 2006-12-13 00:34:04 -0800 | [diff] [blame] | 463 | const struct pipe_buf_operations *ops = buf->ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | int offset = buf->offset + buf->len; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 465 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 467 | int error, atomic = 1; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 468 | void *addr; |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 469 | |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 470 | error = ops->confirm(pipe, buf); |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 471 | if (error) |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 472 | goto out; |
Jens Axboe | f84d751 | 2006-05-01 19:59:03 +0200 | [diff] [blame] | 473 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 474 | iov_fault_in_pages_read(iov, chars); |
| 475 | redo1: |
| 476 | addr = ops->map(pipe, buf, atomic); |
Jens Axboe | 5274f05 | 2006-03-30 15:15:30 +0200 | [diff] [blame] | 477 | error = pipe_iov_copy_from_user(offset + addr, iov, |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 478 | chars, atomic); |
| 479 | ops->unmap(pipe, buf, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | ret = error; |
| 481 | do_wakeup = 1; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 482 | if (error) { |
| 483 | if (atomic) { |
| 484 | atomic = 0; |
| 485 | goto redo1; |
| 486 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | goto out; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 488 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | buf->len += chars; |
| 490 | total_len -= chars; |
| 491 | ret = chars; |
| 492 | if (!total_len) |
| 493 | goto out; |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | for (;;) { |
| 498 | int bufs; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 499 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 500 | if (!pipe->readers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | send_sig(SIGPIPE, current, 0); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 502 | if (!ret) |
| 503 | ret = -EPIPE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | break; |
| 505 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 506 | bufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | if (bufs < PIPE_BUFFERS) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 508 | int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1); |
| 509 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
| 510 | struct page *page = pipe->tmp_page; |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 511 | char *src; |
| 512 | int error, atomic = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | |
| 514 | if (!page) { |
| 515 | page = alloc_page(GFP_HIGHUSER); |
| 516 | if (unlikely(!page)) { |
| 517 | ret = ret ? : -ENOMEM; |
| 518 | break; |
| 519 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 520 | pipe->tmp_page = page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 522 | /* Always wake up, even if the copy fails. Otherwise |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | * we lock up (O_NONBLOCK-)readers that sleep due to |
| 524 | * syscall merging. |
| 525 | * FIXME! Is this really true? |
| 526 | */ |
| 527 | do_wakeup = 1; |
| 528 | chars = PAGE_SIZE; |
| 529 | if (chars > total_len) |
| 530 | chars = total_len; |
| 531 | |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 532 | iov_fault_in_pages_read(iov, chars); |
| 533 | redo2: |
| 534 | if (atomic) |
| 535 | src = kmap_atomic(page, KM_USER0); |
| 536 | else |
| 537 | src = kmap(page); |
| 538 | |
| 539 | error = pipe_iov_copy_from_user(src, iov, chars, |
| 540 | atomic); |
| 541 | if (atomic) |
| 542 | kunmap_atomic(src, KM_USER0); |
| 543 | else |
| 544 | kunmap(page); |
| 545 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | if (unlikely(error)) { |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 547 | if (atomic) { |
| 548 | atomic = 0; |
| 549 | goto redo2; |
| 550 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 551 | if (!ret) |
Jens Axboe | f6762b7 | 2006-05-01 20:02:05 +0200 | [diff] [blame] | 552 | ret = error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | break; |
| 554 | } |
| 555 | ret += chars; |
| 556 | |
| 557 | /* Insert it into the buffer array */ |
| 558 | buf->page = page; |
| 559 | buf->ops = &anon_pipe_buf_ops; |
| 560 | buf->offset = 0; |
| 561 | buf->len = chars; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 562 | pipe->nrbufs = ++bufs; |
| 563 | pipe->tmp_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | |
| 565 | total_len -= chars; |
| 566 | if (!total_len) |
| 567 | break; |
| 568 | } |
| 569 | if (bufs < PIPE_BUFFERS) |
| 570 | continue; |
| 571 | if (filp->f_flags & O_NONBLOCK) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 572 | if (!ret) |
| 573 | ret = -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | break; |
| 575 | } |
| 576 | if (signal_pending(current)) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 577 | if (!ret) |
| 578 | ret = -ERESTARTSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | break; |
| 580 | } |
| 581 | if (do_wakeup) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 582 | wake_up_interruptible_sync(&pipe->wait); |
| 583 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | do_wakeup = 0; |
| 585 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 586 | pipe->waiting_writers++; |
| 587 | pipe_wait(pipe); |
| 588 | pipe->waiting_writers--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | } |
| 590 | out: |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 591 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | if (do_wakeup) { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 593 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 594 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | } |
| 596 | if (ret > 0) |
Christoph Hellwig | 870f481 | 2006-01-09 20:52:01 -0800 | [diff] [blame] | 597 | file_update_time(filp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | return ret; |
| 599 | } |
| 600 | |
| 601 | static ssize_t |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
| 603 | { |
| 604 | return -EBADF; |
| 605 | } |
| 606 | |
| 607 | static ssize_t |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 608 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
| 609 | loff_t *ppos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | { |
| 611 | return -EBADF; |
| 612 | } |
| 613 | |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 614 | 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] | 615 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 616 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 617 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | int count, buf, nrbufs; |
| 619 | |
| 620 | switch (cmd) { |
| 621 | case FIONREAD: |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 622 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 623 | pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | count = 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 625 | buf = pipe->curbuf; |
| 626 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | while (--nrbufs >= 0) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 628 | count += pipe->bufs[buf].len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | buf = (buf+1) & (PIPE_BUFFERS-1); |
| 630 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 631 | mutex_unlock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 632 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | return put_user(count, (int __user *)arg); |
| 634 | default: |
| 635 | return -EINVAL; |
| 636 | } |
| 637 | } |
| 638 | |
| 639 | /* No kernel lock held - fine */ |
| 640 | static unsigned int |
| 641 | pipe_poll(struct file *filp, poll_table *wait) |
| 642 | { |
| 643 | unsigned int mask; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 644 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 645 | struct pipe_inode_info *pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | int nrbufs; |
| 647 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 648 | poll_wait(filp, &pipe->wait, wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | |
| 650 | /* Reading only -- no need for acquiring the semaphore. */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 651 | nrbufs = pipe->nrbufs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | mask = 0; |
| 653 | if (filp->f_mode & FMODE_READ) { |
| 654 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 655 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | mask |= POLLHUP; |
| 657 | } |
| 658 | |
| 659 | if (filp->f_mode & FMODE_WRITE) { |
| 660 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 661 | /* |
| 662 | * Most Unices do not set POLLERR for FIFOs but on Linux they |
| 663 | * behave exactly like pipes for poll(). |
| 664 | */ |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 665 | if (!pipe->readers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | mask |= POLLERR; |
| 667 | } |
| 668 | |
| 669 | return mask; |
| 670 | } |
| 671 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | static int |
| 673 | pipe_release(struct inode *inode, int decr, int decw) |
| 674 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 675 | struct pipe_inode_info *pipe; |
| 676 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 677 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 678 | pipe = inode->i_pipe; |
| 679 | pipe->readers -= decr; |
| 680 | pipe->writers -= decw; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 681 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 682 | if (!pipe->readers && !pipe->writers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | free_pipe_info(inode); |
| 684 | } else { |
Ingo Molnar | 71e20f1 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 685 | wake_up_interruptible_sync(&pipe->wait); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 686 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 687 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 689 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | |
| 691 | return 0; |
| 692 | } |
| 693 | |
| 694 | static int |
| 695 | pipe_read_fasync(int fd, struct file *filp, int on) |
| 696 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 697 | struct inode *inode = filp->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | int retval; |
| 699 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 700 | mutex_lock(&inode->i_mutex); |
| 701 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); |
| 702 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 704 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | } |
| 706 | |
| 707 | |
| 708 | static int |
| 709 | pipe_write_fasync(int fd, struct file *filp, int on) |
| 710 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 711 | struct inode *inode = filp->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | int retval; |
| 713 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 714 | mutex_lock(&inode->i_mutex); |
| 715 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); |
| 716 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 718 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 719 | } |
| 720 | |
| 721 | |
| 722 | static int |
| 723 | pipe_rdwr_fasync(int fd, struct file *filp, int on) |
| 724 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 725 | struct inode *inode = filp->f_path.dentry->d_inode; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 726 | struct pipe_inode_info *pipe = inode->i_pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | int retval; |
| 728 | |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 729 | mutex_lock(&inode->i_mutex); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 730 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 731 | if (retval >= 0) { |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 732 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
Oleg Nesterov | e5bc49b | 2009-03-12 14:31:28 -0700 | [diff] [blame] | 733 | if (retval < 0) /* this can happen only if on == T */ |
| 734 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
| 735 | } |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 736 | mutex_unlock(&inode->i_mutex); |
Jonathan Corbet | 60aa492 | 2009-02-01 14:52:56 -0700 | [diff] [blame] | 737 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | } |
| 739 | |
| 740 | |
| 741 | static int |
| 742 | pipe_read_release(struct inode *inode, struct file *filp) |
| 743 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | return pipe_release(inode, 1, 0); |
| 745 | } |
| 746 | |
| 747 | static int |
| 748 | pipe_write_release(struct inode *inode, struct file *filp) |
| 749 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | return pipe_release(inode, 0, 1); |
| 751 | } |
| 752 | |
| 753 | static int |
| 754 | pipe_rdwr_release(struct inode *inode, struct file *filp) |
| 755 | { |
| 756 | int decr, decw; |
| 757 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | decr = (filp->f_mode & FMODE_READ) != 0; |
| 759 | decw = (filp->f_mode & FMODE_WRITE) != 0; |
| 760 | return pipe_release(inode, decr, decw); |
| 761 | } |
| 762 | |
| 763 | static int |
| 764 | pipe_read_open(struct inode *inode, struct file *filp) |
| 765 | { |
| 766 | /* We could have perhaps used atomic_t, but this and friends |
| 767 | below are the only places. So it doesn't seem worthwhile. */ |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 768 | mutex_lock(&inode->i_mutex); |
| 769 | inode->i_pipe->readers++; |
| 770 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | |
| 772 | return 0; |
| 773 | } |
| 774 | |
| 775 | static int |
| 776 | pipe_write_open(struct inode *inode, struct file *filp) |
| 777 | { |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 778 | mutex_lock(&inode->i_mutex); |
| 779 | inode->i_pipe->writers++; |
| 780 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | |
| 782 | return 0; |
| 783 | } |
| 784 | |
| 785 | static int |
| 786 | pipe_rdwr_open(struct inode *inode, struct file *filp) |
| 787 | { |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 788 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | if (filp->f_mode & FMODE_READ) |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 790 | inode->i_pipe->readers++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | if (filp->f_mode & FMODE_WRITE) |
Ingo Molnar | 9aeedfc | 2006-04-11 13:53:10 +0200 | [diff] [blame] | 792 | inode->i_pipe->writers++; |
| 793 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 794 | |
| 795 | return 0; |
| 796 | } |
| 797 | |
| 798 | /* |
| 799 | * The file_operations structs are not static because they |
| 800 | * 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] | 801 | * |
| 802 | * Pipes reuse fifos' file_operations structs. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 803 | */ |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 804 | const struct file_operations read_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | .llseek = no_llseek, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 806 | .read = do_sync_read, |
| 807 | .aio_read = pipe_read, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | .write = bad_pipe_w, |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 809 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 810 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 811 | .open = pipe_read_open, |
| 812 | .release = pipe_read_release, |
| 813 | .fasync = pipe_read_fasync, |
| 814 | }; |
| 815 | |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 816 | const struct file_operations write_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | .llseek = no_llseek, |
| 818 | .read = bad_pipe_r, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 819 | .write = do_sync_write, |
| 820 | .aio_write = pipe_write, |
Pekka Enberg | 5e5d7a2 | 2005-09-06 15:17:48 -0700 | [diff] [blame] | 821 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 822 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 823 | .open = pipe_write_open, |
| 824 | .release = pipe_write_release, |
| 825 | .fasync = pipe_write_fasync, |
| 826 | }; |
| 827 | |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 828 | const struct file_operations rdwr_pipefifo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | .llseek = no_llseek, |
Badari Pulavarty | ee0b3e6 | 2006-09-30 23:28:47 -0700 | [diff] [blame] | 830 | .read = do_sync_read, |
| 831 | .aio_read = pipe_read, |
| 832 | .write = do_sync_write, |
| 833 | .aio_write = pipe_write, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 834 | .poll = pipe_poll, |
Andi Kleen | d59d0b1 | 2008-02-08 04:21:23 -0800 | [diff] [blame] | 835 | .unlocked_ioctl = pipe_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | .open = pipe_rdwr_open, |
| 837 | .release = pipe_rdwr_release, |
| 838 | .fasync = pipe_rdwr_fasync, |
| 839 | }; |
| 840 | |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 841 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
| 842 | { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 843 | struct pipe_inode_info *pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 844 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 845 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
| 846 | if (pipe) { |
| 847 | init_waitqueue_head(&pipe->wait); |
| 848 | pipe->r_counter = pipe->w_counter = 1; |
| 849 | pipe->inode = inode; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 850 | } |
| 851 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 852 | return pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 853 | } |
| 854 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 855 | void __free_pipe_info(struct pipe_inode_info *pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 856 | { |
| 857 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | for (i = 0; i < PIPE_BUFFERS; i++) { |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 860 | struct pipe_buffer *buf = pipe->bufs + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | if (buf->ops) |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 862 | buf->ops->release(pipe, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | } |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 864 | if (pipe->tmp_page) |
| 865 | __free_page(pipe->tmp_page); |
| 866 | kfree(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | } |
| 868 | |
Jens Axboe | b92ce55 | 2006-04-11 13:52:07 +0200 | [diff] [blame] | 869 | void free_pipe_info(struct inode *inode) |
| 870 | { |
| 871 | __free_pipe_info(inode->i_pipe); |
| 872 | inode->i_pipe = NULL; |
| 873 | } |
| 874 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 875 | static struct vfsmount *pipe_mnt __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | static int pipefs_delete_dentry(struct dentry *dentry) |
| 877 | { |
Eric Dumazet | d18de5a | 2006-12-06 20:38:45 -0800 | [diff] [blame] | 878 | /* |
| 879 | * At creation time, we pretended this dentry was hashed |
| 880 | * (by clearing DCACHE_UNHASHED bit in d_flags) |
| 881 | * At delete time, we restore the truth : not hashed. |
| 882 | * (so that dput() can proceed correctly) |
| 883 | */ |
| 884 | dentry->d_flags |= DCACHE_UNHASHED; |
| 885 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 886 | } |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 887 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 888 | /* |
| 889 | * pipefs_dname() is called from d_path(). |
| 890 | */ |
| 891 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) |
| 892 | { |
| 893 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", |
| 894 | dentry->d_inode->i_ino); |
| 895 | } |
| 896 | |
Al Viro | 3ba13d1 | 2009-02-20 06:02:22 +0000 | [diff] [blame] | 897 | static const struct dentry_operations pipefs_dentry_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | .d_delete = pipefs_delete_dentry, |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 899 | .d_dname = pipefs_dname, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 900 | }; |
| 901 | |
| 902 | static struct inode * get_pipe_inode(void) |
| 903 | { |
| 904 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 905 | struct pipe_inode_info *pipe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | |
| 907 | if (!inode) |
| 908 | goto fail_inode; |
| 909 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 910 | pipe = alloc_pipe_info(inode); |
| 911 | if (!pipe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | goto fail_iput; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 913 | inode->i_pipe = pipe; |
Ingo Molnar | 3a326a2 | 2006-04-10 15:18:35 +0200 | [diff] [blame] | 914 | |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 915 | pipe->readers = pipe->writers = 1; |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 916 | inode->i_fop = &rdwr_pipefifo_fops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 917 | |
| 918 | /* |
| 919 | * Mark the inode dirty from the very beginning, |
| 920 | * that way it will never be moved to the dirty |
| 921 | * list because "mark_inode_dirty()" will think |
| 922 | * that it already _is_ on the dirty list. |
| 923 | */ |
| 924 | inode->i_state = I_DIRTY; |
| 925 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 926 | inode->i_uid = current_fsuid(); |
| 927 | inode->i_gid = current_fsgid(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 928 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
Ingo Molnar | 923f4f2 | 2006-04-11 13:53:33 +0200 | [diff] [blame] | 929 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 930 | return inode; |
| 931 | |
| 932 | fail_iput: |
| 933 | iput(inode); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 934 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | fail_inode: |
| 936 | return NULL; |
| 937 | } |
| 938 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 939 | struct file *create_write_pipe(int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | { |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 941 | int err; |
| 942 | struct inode *inode; |
| 943 | struct file *f; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 944 | struct dentry *dentry; |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 945 | struct qstr name = { .name = "" }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 946 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 947 | err = -ENFILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 948 | inode = get_pipe_inode(); |
| 949 | if (!inode) |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 950 | goto err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 951 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 952 | err = -ENOMEM; |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 953 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 954 | if (!dentry) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 955 | goto err_inode; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 956 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | dentry->d_op = &pipefs_dentry_operations; |
Eric Dumazet | d18de5a | 2006-12-06 20:38:45 -0800 | [diff] [blame] | 958 | /* |
| 959 | * We dont want to publish this dentry into global dentry hash table. |
| 960 | * We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED |
| 961 | * This permits a working /proc/$pid/fd/XXX on pipes |
| 962 | */ |
| 963 | dentry->d_flags &= ~DCACHE_UNHASHED; |
| 964 | d_instantiate(dentry, inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 965 | |
| 966 | err = -ENFILE; |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 967 | f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipefifo_fops); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 968 | if (!f) |
| 969 | goto err_dentry; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 970 | f->f_mapping = inode->i_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 972 | f->f_flags = O_WRONLY | (flags & O_NONBLOCK); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 973 | f->f_version = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 975 | return f; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 977 | err_dentry: |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 978 | free_pipe_info(inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 979 | dput(dentry); |
Al Viro | ed15243 | 2008-04-22 19:51:27 -0400 | [diff] [blame] | 980 | return ERR_PTR(err); |
| 981 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 982 | err_inode: |
| 983 | free_pipe_info(inode); |
| 984 | iput(inode); |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 985 | err: |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 986 | return ERR_PTR(err); |
| 987 | } |
| 988 | |
| 989 | void free_write_pipe(struct file *f) |
| 990 | { |
Al Viro | 5ccac88e | 2006-12-18 13:31:18 +0000 | [diff] [blame] | 991 | free_pipe_info(f->f_dentry->d_inode); |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 992 | path_put(&f->f_path); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 993 | put_filp(f); |
| 994 | } |
| 995 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 996 | struct file *create_read_pipe(struct file *wrf, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 997 | { |
| 998 | struct file *f = get_empty_filp(); |
| 999 | if (!f) |
| 1000 | return ERR_PTR(-ENFILE); |
| 1001 | |
| 1002 | /* Grab pipe from the writer */ |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1003 | f->f_path = wrf->f_path; |
| 1004 | path_get(&wrf->f_path); |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1005 | f->f_mapping = wrf->f_path.dentry->d_inode->i_mapping; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1006 | |
| 1007 | f->f_pos = 0; |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1008 | f->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
Denys Vlasenko | d2d9648 | 2008-07-01 14:16:09 +0200 | [diff] [blame] | 1009 | f->f_op = &read_pipefifo_fops; |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1010 | f->f_mode = FMODE_READ; |
| 1011 | f->f_version = 0; |
| 1012 | |
| 1013 | return f; |
| 1014 | } |
| 1015 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1016 | int do_pipe_flags(int *fd, int flags) |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1017 | { |
| 1018 | struct file *fw, *fr; |
| 1019 | int error; |
| 1020 | int fdw, fdr; |
| 1021 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1022 | if (flags & ~(O_CLOEXEC | O_NONBLOCK)) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1023 | return -EINVAL; |
| 1024 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1025 | fw = create_write_pipe(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1026 | if (IS_ERR(fw)) |
| 1027 | return PTR_ERR(fw); |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 1028 | fr = create_read_pipe(fw, flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1029 | error = PTR_ERR(fr); |
| 1030 | if (IS_ERR(fr)) |
| 1031 | goto err_write_pipe; |
| 1032 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1033 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1034 | if (error < 0) |
| 1035 | goto err_read_pipe; |
| 1036 | fdr = error; |
| 1037 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1038 | error = get_unused_fd_flags(flags); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1039 | if (error < 0) |
| 1040 | goto err_fdr; |
| 1041 | fdw = error; |
| 1042 | |
Al Viro | 157cf64 | 2008-12-14 04:57:47 -0500 | [diff] [blame] | 1043 | audit_fd_pair(fdr, fdw); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1044 | fd_install(fdr, fr); |
| 1045 | fd_install(fdw, fw); |
| 1046 | fd[0] = fdr; |
| 1047 | fd[1] = fdw; |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1048 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | return 0; |
| 1050 | |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1051 | err_fdr: |
| 1052 | put_unused_fd(fdr); |
| 1053 | err_read_pipe: |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1054 | path_put(&fr->f_path); |
Andi Kleen | d6cbd28 | 2006-09-30 23:29:26 -0700 | [diff] [blame] | 1055 | put_filp(fr); |
| 1056 | err_write_pipe: |
| 1057 | free_write_pipe(fw); |
| 1058 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | } |
| 1060 | |
| 1061 | /* |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1062 | * sys_pipe() is the normal C calling standard for creating |
| 1063 | * a pipe. It's not the way Unix traditionally does this, though. |
| 1064 | */ |
Heiko Carstens | d4e8204 | 2009-01-14 14:14:34 +0100 | [diff] [blame] | 1065 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1066 | { |
| 1067 | int fd[2]; |
| 1068 | int error; |
| 1069 | |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1070 | error = do_pipe_flags(fd, flags); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1071 | if (!error) { |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 1072 | if (copy_to_user(fildes, fd, sizeof(fd))) { |
| 1073 | sys_close(fd[0]); |
| 1074 | sys_close(fd[1]); |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1075 | error = -EFAULT; |
Ulrich Drepper | ba719ba | 2008-05-06 20:42:38 -0700 | [diff] [blame] | 1076 | } |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1077 | } |
| 1078 | return error; |
| 1079 | } |
| 1080 | |
Heiko Carstens | 2b66421 | 2009-01-14 14:14:35 +0100 | [diff] [blame] | 1081 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
Ulrich Drepper | ed8cae8 | 2008-07-23 21:29:30 -0700 | [diff] [blame] | 1082 | { |
| 1083 | return sys_pipe2(fildes, 0); |
| 1084 | } |
| 1085 | |
Ulrich Drepper | d35c7b0 | 2008-05-03 15:10:37 -0400 | [diff] [blame] | 1086 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1087 | * pipefs should _never_ be mounted by userland - too much of security hassle, |
| 1088 | * no real gain from having the whole whorehouse mounted. So we don't need |
| 1089 | * any operations on the root directory. However, we need a non-trivial |
| 1090 | * d_name - pipe: will go nicely and kill the special-casing in procfs. |
| 1091 | */ |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1092 | static int pipefs_get_sb(struct file_system_type *fs_type, |
| 1093 | int flags, const char *dev_name, void *data, |
| 1094 | struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | { |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1096 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | } |
| 1098 | |
| 1099 | static struct file_system_type pipe_fs_type = { |
| 1100 | .name = "pipefs", |
| 1101 | .get_sb = pipefs_get_sb, |
| 1102 | .kill_sb = kill_anon_super, |
| 1103 | }; |
| 1104 | |
| 1105 | static int __init init_pipe_fs(void) |
| 1106 | { |
| 1107 | int err = register_filesystem(&pipe_fs_type); |
Ingo Molnar | 341b446 | 2006-04-11 13:57:45 +0200 | [diff] [blame] | 1108 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | if (!err) { |
| 1110 | pipe_mnt = kern_mount(&pipe_fs_type); |
| 1111 | if (IS_ERR(pipe_mnt)) { |
| 1112 | err = PTR_ERR(pipe_mnt); |
| 1113 | unregister_filesystem(&pipe_fs_type); |
| 1114 | } |
| 1115 | } |
| 1116 | return err; |
| 1117 | } |
| 1118 | |
| 1119 | static void __exit exit_pipe_fs(void) |
| 1120 | { |
| 1121 | unregister_filesystem(&pipe_fs_type); |
| 1122 | mntput(pipe_mnt); |
| 1123 | } |
| 1124 | |
| 1125 | fs_initcall(init_pipe_fs); |
| 1126 | module_exit(exit_pipe_fs); |