| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * "splice": joining two ropes together by interweaving their strands. |
| 4 | * |
| 5 | * This is the "extended pipe" functionality, where a pipe is used as |
| 6 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel |
| 7 | * buffer that you can use to transfer data from one end to the other. |
| 8 | * |
| 9 | * The traditional unix read/write is extended with a "splice()" operation |
| 10 | * that transfers data buffers to or from a pipe buffer. |
| 11 | * |
| 12 | * Named by Larry McVoy, original implementation from Linus, extended by |
| 13 | * Jens to support splicing to files, network, direct splicing, etc and |
| 14 | * fixing lots of bugs. |
| 15 | * |
| 16 | * Copyright (C) 2005-2006 Jens Axboe <axboe@kernel.dk> |
| 17 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> |
| 18 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> |
| 19 | * |
| 20 | */ |
| 21 | #include <linux/bvec.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/file.h> |
| 24 | #include <linux/pagemap.h> |
| 25 | #include <linux/splice.h> |
| 26 | #include <linux/memcontrol.h> |
| 27 | #include <linux/mm_inline.h> |
| 28 | #include <linux/swap.h> |
| 29 | #include <linux/writeback.h> |
| 30 | #include <linux/export.h> |
| 31 | #include <linux/syscalls.h> |
| 32 | #include <linux/uio.h> |
| 33 | #include <linux/fsnotify.h> |
| 34 | #include <linux/security.h> |
| 35 | #include <linux/gfp.h> |
| 36 | #include <linux/socket.h> |
| 37 | #include <linux/sched/signal.h> |
| 38 | |
| 39 | #include "internal.h" |
| 40 | |
| 41 | /* |
| 42 | * Attempt to steal a page from a pipe buffer. This should perhaps go into |
| 43 | * a vm helper function, it's already simplified quite a bit by the |
| 44 | * addition of remove_mapping(). If success is returned, the caller may |
| 45 | * attempt to reuse this page for another destination. |
| 46 | */ |
| 47 | static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 48 | struct pipe_buffer *buf) |
| 49 | { |
| 50 | struct folio *folio = page_folio(buf->page); |
| 51 | struct address_space *mapping; |
| 52 | |
| 53 | folio_lock(folio); |
| 54 | |
| 55 | mapping = folio_mapping(folio); |
| 56 | if (mapping) { |
| 57 | WARN_ON(!folio_test_uptodate(folio)); |
| 58 | |
| 59 | /* |
| 60 | * At least for ext2 with nobh option, we need to wait on |
| 61 | * writeback completing on this folio, since we'll remove it |
| 62 | * from the pagecache. Otherwise truncate wont wait on the |
| 63 | * folio, allowing the disk blocks to be reused by someone else |
| 64 | * before we actually wrote our data to them. fs corruption |
| 65 | * ensues. |
| 66 | */ |
| 67 | folio_wait_writeback(folio); |
| 68 | |
| 69 | if (folio_has_private(folio) && |
| 70 | !filemap_release_folio(folio, GFP_KERNEL)) |
| 71 | goto out_unlock; |
| 72 | |
| 73 | /* |
| 74 | * If we succeeded in removing the mapping, set LRU flag |
| 75 | * and return good. |
| 76 | */ |
| 77 | if (remove_mapping(mapping, folio)) { |
| 78 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 79 | return true; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * Raced with truncate or failed to remove folio from current |
| 85 | * address space, unlock and return failure. |
| 86 | */ |
| 87 | out_unlock: |
| 88 | folio_unlock(folio); |
| 89 | return false; |
| 90 | } |
| 91 | |
| 92 | static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, |
| 93 | struct pipe_buffer *buf) |
| 94 | { |
| 95 | put_page(buf->page); |
| 96 | buf->flags &= ~PIPE_BUF_FLAG_LRU; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * Check whether the contents of buf is OK to access. Since the content |
| 101 | * is a page cache page, IO may be in flight. |
| 102 | */ |
| 103 | static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, |
| 104 | struct pipe_buffer *buf) |
| 105 | { |
| 106 | struct page *page = buf->page; |
| 107 | int err; |
| 108 | |
| 109 | if (!PageUptodate(page)) { |
| 110 | lock_page(page); |
| 111 | |
| 112 | /* |
| 113 | * Page got truncated/unhashed. This will cause a 0-byte |
| 114 | * splice, if this is the first page. |
| 115 | */ |
| 116 | if (!page->mapping) { |
| 117 | err = -ENODATA; |
| 118 | goto error; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Uh oh, read-error from disk. |
| 123 | */ |
| 124 | if (!PageUptodate(page)) { |
| 125 | err = -EIO; |
| 126 | goto error; |
| 127 | } |
| 128 | |
| 129 | /* |
| 130 | * Page is ok afterall, we are done. |
| 131 | */ |
| 132 | unlock_page(page); |
| 133 | } |
| 134 | |
| 135 | return 0; |
| 136 | error: |
| 137 | unlock_page(page); |
| 138 | return err; |
| 139 | } |
| 140 | |
| 141 | const struct pipe_buf_operations page_cache_pipe_buf_ops = { |
| 142 | .confirm = page_cache_pipe_buf_confirm, |
| 143 | .release = page_cache_pipe_buf_release, |
| 144 | .try_steal = page_cache_pipe_buf_try_steal, |
| 145 | .get = generic_pipe_buf_get, |
| 146 | }; |
| 147 | |
| 148 | static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe, |
| 149 | struct pipe_buffer *buf) |
| 150 | { |
| 151 | if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) |
| 152 | return false; |
| 153 | |
| 154 | buf->flags |= PIPE_BUF_FLAG_LRU; |
| 155 | return generic_pipe_buf_try_steal(pipe, buf); |
| 156 | } |
| 157 | |
| 158 | static const struct pipe_buf_operations user_page_pipe_buf_ops = { |
| 159 | .release = page_cache_pipe_buf_release, |
| 160 | .try_steal = user_page_pipe_buf_try_steal, |
| 161 | .get = generic_pipe_buf_get, |
| 162 | }; |
| 163 | |
| 164 | static void wakeup_pipe_readers(struct pipe_inode_info *pipe) |
| 165 | { |
| 166 | smp_mb(); |
| 167 | if (waitqueue_active(&pipe->rd_wait)) |
| 168 | wake_up_interruptible(&pipe->rd_wait); |
| 169 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * splice_to_pipe - fill passed data into a pipe |
| 174 | * @pipe: pipe to fill |
| 175 | * @spd: data to fill |
| 176 | * |
| 177 | * Description: |
| 178 | * @spd contains a map of pages and len/offset tuples, along with |
| 179 | * the struct pipe_buf_operations associated with these pages. This |
| 180 | * function will link that data to the pipe. |
| 181 | * |
| 182 | */ |
| 183 | ssize_t splice_to_pipe(struct pipe_inode_info *pipe, |
| 184 | struct splice_pipe_desc *spd) |
| 185 | { |
| 186 | unsigned int spd_pages = spd->nr_pages; |
| 187 | unsigned int tail = pipe->tail; |
| 188 | unsigned int head = pipe->head; |
| 189 | unsigned int mask = pipe->ring_size - 1; |
| 190 | int ret = 0, page_nr = 0; |
| 191 | |
| 192 | if (!spd_pages) |
| 193 | return 0; |
| 194 | |
| 195 | if (unlikely(!pipe->readers)) { |
| 196 | send_sig(SIGPIPE, current, 0); |
| 197 | ret = -EPIPE; |
| 198 | goto out; |
| 199 | } |
| 200 | |
| 201 | while (!pipe_full(head, tail, pipe->max_usage)) { |
| 202 | struct pipe_buffer *buf = &pipe->bufs[head & mask]; |
| 203 | |
| 204 | buf->page = spd->pages[page_nr]; |
| 205 | buf->offset = spd->partial[page_nr].offset; |
| 206 | buf->len = spd->partial[page_nr].len; |
| 207 | buf->private = spd->partial[page_nr].private; |
| 208 | buf->ops = spd->ops; |
| 209 | buf->flags = 0; |
| 210 | |
| 211 | head++; |
| 212 | pipe->head = head; |
| 213 | page_nr++; |
| 214 | ret += buf->len; |
| 215 | |
| 216 | if (!--spd->nr_pages) |
| 217 | break; |
| 218 | } |
| 219 | |
| 220 | if (!ret) |
| 221 | ret = -EAGAIN; |
| 222 | |
| 223 | out: |
| 224 | while (page_nr < spd_pages) |
| 225 | spd->spd_release(spd, page_nr++); |
| 226 | |
| 227 | return ret; |
| 228 | } |
| 229 | EXPORT_SYMBOL_GPL(splice_to_pipe); |
| 230 | |
| 231 | ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf) |
| 232 | { |
| 233 | unsigned int head = pipe->head; |
| 234 | unsigned int tail = pipe->tail; |
| 235 | unsigned int mask = pipe->ring_size - 1; |
| 236 | int ret; |
| 237 | |
| 238 | if (unlikely(!pipe->readers)) { |
| 239 | send_sig(SIGPIPE, current, 0); |
| 240 | ret = -EPIPE; |
| 241 | } else if (pipe_full(head, tail, pipe->max_usage)) { |
| 242 | ret = -EAGAIN; |
| 243 | } else { |
| 244 | pipe->bufs[head & mask] = *buf; |
| 245 | pipe->head = head + 1; |
| 246 | return buf->len; |
| 247 | } |
| 248 | pipe_buf_release(pipe, buf); |
| 249 | return ret; |
| 250 | } |
| 251 | EXPORT_SYMBOL(add_to_pipe); |
| 252 | |
| 253 | /* |
| 254 | * Check if we need to grow the arrays holding pages and partial page |
| 255 | * descriptions. |
| 256 | */ |
| 257 | int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd) |
| 258 | { |
| 259 | unsigned int max_usage = READ_ONCE(pipe->max_usage); |
| 260 | |
| 261 | spd->nr_pages_max = max_usage; |
| 262 | if (max_usage <= PIPE_DEF_BUFFERS) |
| 263 | return 0; |
| 264 | |
| 265 | spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL); |
| 266 | spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page), |
| 267 | GFP_KERNEL); |
| 268 | |
| 269 | if (spd->pages && spd->partial) |
| 270 | return 0; |
| 271 | |
| 272 | kfree(spd->pages); |
| 273 | kfree(spd->partial); |
| 274 | return -ENOMEM; |
| 275 | } |
| 276 | |
| 277 | void splice_shrink_spd(struct splice_pipe_desc *spd) |
| 278 | { |
| 279 | if (spd->nr_pages_max <= PIPE_DEF_BUFFERS) |
| 280 | return; |
| 281 | |
| 282 | kfree(spd->pages); |
| 283 | kfree(spd->partial); |
| 284 | } |
| 285 | |
| 286 | /* |
| 287 | * Splice data from an O_DIRECT file into pages and then add them to the output |
| 288 | * pipe. |
| 289 | */ |
| 290 | ssize_t direct_splice_read(struct file *in, loff_t *ppos, |
| 291 | struct pipe_inode_info *pipe, |
| 292 | size_t len, unsigned int flags) |
| 293 | { |
| 294 | struct iov_iter to; |
| 295 | struct bio_vec *bv; |
| 296 | struct kiocb kiocb; |
| 297 | struct page **pages; |
| 298 | ssize_t ret; |
| 299 | size_t used, npages, chunk, remain, reclaim; |
| 300 | int i; |
| 301 | |
| 302 | /* Work out how much data we can actually add into the pipe */ |
| 303 | used = pipe_occupancy(pipe->head, pipe->tail); |
| 304 | npages = max_t(ssize_t, pipe->max_usage - used, 0); |
| 305 | len = min_t(size_t, len, npages * PAGE_SIZE); |
| 306 | npages = DIV_ROUND_UP(len, PAGE_SIZE); |
| 307 | |
| 308 | bv = kzalloc(array_size(npages, sizeof(bv[0])) + |
| 309 | array_size(npages, sizeof(struct page *)), GFP_KERNEL); |
| 310 | if (!bv) |
| 311 | return -ENOMEM; |
| 312 | |
| 313 | pages = (void *)(bv + npages); |
| 314 | npages = alloc_pages_bulk_array(GFP_USER, npages, pages); |
| 315 | if (!npages) { |
| 316 | kfree(bv); |
| 317 | return -ENOMEM; |
| 318 | } |
| 319 | |
| 320 | remain = len = min_t(size_t, len, npages * PAGE_SIZE); |
| 321 | |
| 322 | for (i = 0; i < npages; i++) { |
| 323 | chunk = min_t(size_t, PAGE_SIZE, remain); |
| 324 | bv[i].bv_page = pages[i]; |
| 325 | bv[i].bv_offset = 0; |
| 326 | bv[i].bv_len = chunk; |
| 327 | remain -= chunk; |
| 328 | } |
| 329 | |
| 330 | /* Do the I/O */ |
| 331 | iov_iter_bvec(&to, ITER_DEST, bv, npages, len); |
| 332 | init_sync_kiocb(&kiocb, in); |
| 333 | kiocb.ki_pos = *ppos; |
| 334 | ret = call_read_iter(in, &kiocb, &to); |
| 335 | |
| 336 | reclaim = npages * PAGE_SIZE; |
| 337 | remain = 0; |
| 338 | if (ret > 0) { |
| 339 | reclaim -= ret; |
| 340 | remain = ret; |
| 341 | *ppos = kiocb.ki_pos; |
| 342 | file_accessed(in); |
| 343 | } else if (ret < 0) { |
| 344 | /* |
| 345 | * callers of ->splice_read() expect -EAGAIN on |
| 346 | * "can't put anything in there", rather than -EFAULT. |
| 347 | */ |
| 348 | if (ret == -EFAULT) |
| 349 | ret = -EAGAIN; |
| 350 | } |
| 351 | |
| 352 | /* Free any pages that didn't get touched at all. */ |
| 353 | reclaim /= PAGE_SIZE; |
| 354 | if (reclaim) { |
| 355 | npages -= reclaim; |
| 356 | release_pages(pages + npages, reclaim); |
| 357 | } |
| 358 | |
| 359 | /* Push the remaining pages into the pipe. */ |
| 360 | for (i = 0; i < npages; i++) { |
| 361 | struct pipe_buffer *buf = pipe_head_buf(pipe); |
| 362 | |
| 363 | chunk = min_t(size_t, remain, PAGE_SIZE); |
| 364 | *buf = (struct pipe_buffer) { |
| 365 | .ops = &default_pipe_buf_ops, |
| 366 | .page = bv[i].bv_page, |
| 367 | .offset = 0, |
| 368 | .len = chunk, |
| 369 | }; |
| 370 | pipe->head++; |
| 371 | remain -= chunk; |
| 372 | } |
| 373 | |
| 374 | kfree(bv); |
| 375 | return ret; |
| 376 | } |
| 377 | EXPORT_SYMBOL(direct_splice_read); |
| 378 | |
| 379 | /** |
| 380 | * generic_file_splice_read - splice data from file to a pipe |
| 381 | * @in: file to splice from |
| 382 | * @ppos: position in @in |
| 383 | * @pipe: pipe to splice to |
| 384 | * @len: number of bytes to splice |
| 385 | * @flags: splice modifier flags |
| 386 | * |
| 387 | * Description: |
| 388 | * Will read pages from given file and fill them into a pipe. Can be |
| 389 | * used as long as it has more or less sane ->read_iter(). |
| 390 | * |
| 391 | */ |
| 392 | ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, |
| 393 | struct pipe_inode_info *pipe, size_t len, |
| 394 | unsigned int flags) |
| 395 | { |
| 396 | struct iov_iter to; |
| 397 | struct kiocb kiocb; |
| 398 | int ret; |
| 399 | |
| 400 | iov_iter_pipe(&to, ITER_DEST, pipe, len); |
| 401 | init_sync_kiocb(&kiocb, in); |
| 402 | kiocb.ki_pos = *ppos; |
| 403 | ret = call_read_iter(in, &kiocb, &to); |
| 404 | if (ret > 0) { |
| 405 | *ppos = kiocb.ki_pos; |
| 406 | file_accessed(in); |
| 407 | } else if (ret < 0) { |
| 408 | /* free what was emitted */ |
| 409 | pipe_discard_from(pipe, to.start_head); |
| 410 | /* |
| 411 | * callers of ->splice_read() expect -EAGAIN on |
| 412 | * "can't put anything in there", rather than -EFAULT. |
| 413 | */ |
| 414 | if (ret == -EFAULT) |
| 415 | ret = -EAGAIN; |
| 416 | } |
| 417 | |
| 418 | return ret; |
| 419 | } |
| 420 | EXPORT_SYMBOL(generic_file_splice_read); |
| 421 | |
| 422 | const struct pipe_buf_operations default_pipe_buf_ops = { |
| 423 | .release = generic_pipe_buf_release, |
| 424 | .try_steal = generic_pipe_buf_try_steal, |
| 425 | .get = generic_pipe_buf_get, |
| 426 | }; |
| 427 | |
| 428 | /* Pipe buffer operations for a socket and similar. */ |
| 429 | const struct pipe_buf_operations nosteal_pipe_buf_ops = { |
| 430 | .release = generic_pipe_buf_release, |
| 431 | .get = generic_pipe_buf_get, |
| 432 | }; |
| 433 | EXPORT_SYMBOL(nosteal_pipe_buf_ops); |
| 434 | |
| 435 | /* |
| 436 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
| 437 | * using sendpage(). Return the number of bytes sent. |
| 438 | */ |
| 439 | static int pipe_to_sendpage(struct pipe_inode_info *pipe, |
| 440 | struct pipe_buffer *buf, struct splice_desc *sd) |
| 441 | { |
| 442 | struct file *file = sd->u.file; |
| 443 | loff_t pos = sd->pos; |
| 444 | int more; |
| 445 | |
| 446 | if (!likely(file->f_op->sendpage)) |
| 447 | return -EINVAL; |
| 448 | |
| 449 | more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; |
| 450 | |
| 451 | if (sd->len < sd->total_len && |
| 452 | pipe_occupancy(pipe->head, pipe->tail) > 1) |
| 453 | more |= MSG_SENDPAGE_NOTLAST; |
| 454 | |
| 455 | return file->f_op->sendpage(file, buf->page, buf->offset, |
| 456 | sd->len, &pos, more); |
| 457 | } |
| 458 | |
| 459 | static void wakeup_pipe_writers(struct pipe_inode_info *pipe) |
| 460 | { |
| 461 | smp_mb(); |
| 462 | if (waitqueue_active(&pipe->wr_wait)) |
| 463 | wake_up_interruptible(&pipe->wr_wait); |
| 464 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
| 465 | } |
| 466 | |
| 467 | /** |
| 468 | * splice_from_pipe_feed - feed available data from a pipe to a file |
| 469 | * @pipe: pipe to splice from |
| 470 | * @sd: information to @actor |
| 471 | * @actor: handler that splices the data |
| 472 | * |
| 473 | * Description: |
| 474 | * This function loops over the pipe and calls @actor to do the |
| 475 | * actual moving of a single struct pipe_buffer to the desired |
| 476 | * destination. It returns when there's no more buffers left in |
| 477 | * the pipe or if the requested number of bytes (@sd->total_len) |
| 478 | * have been copied. It returns a positive number (one) if the |
| 479 | * pipe needs to be filled with more data, zero if the required |
| 480 | * number of bytes have been copied and -errno on error. |
| 481 | * |
| 482 | * This, together with splice_from_pipe_{begin,end,next}, may be |
| 483 | * used to implement the functionality of __splice_from_pipe() when |
| 484 | * locking is required around copying the pipe buffers to the |
| 485 | * destination. |
| 486 | */ |
| 487 | static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 488 | splice_actor *actor) |
| 489 | { |
| 490 | unsigned int head = pipe->head; |
| 491 | unsigned int tail = pipe->tail; |
| 492 | unsigned int mask = pipe->ring_size - 1; |
| 493 | int ret; |
| 494 | |
| 495 | while (!pipe_empty(head, tail)) { |
| 496 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 497 | |
| 498 | sd->len = buf->len; |
| 499 | if (sd->len > sd->total_len) |
| 500 | sd->len = sd->total_len; |
| 501 | |
| 502 | ret = pipe_buf_confirm(pipe, buf); |
| 503 | if (unlikely(ret)) { |
| 504 | if (ret == -ENODATA) |
| 505 | ret = 0; |
| 506 | return ret; |
| 507 | } |
| 508 | |
| 509 | ret = actor(pipe, buf, sd); |
| 510 | if (ret <= 0) |
| 511 | return ret; |
| 512 | |
| 513 | buf->offset += ret; |
| 514 | buf->len -= ret; |
| 515 | |
| 516 | sd->num_spliced += ret; |
| 517 | sd->len -= ret; |
| 518 | sd->pos += ret; |
| 519 | sd->total_len -= ret; |
| 520 | |
| 521 | if (!buf->len) { |
| 522 | pipe_buf_release(pipe, buf); |
| 523 | tail++; |
| 524 | pipe->tail = tail; |
| 525 | if (pipe->files) |
| 526 | sd->need_wakeup = true; |
| 527 | } |
| 528 | |
| 529 | if (!sd->total_len) |
| 530 | return 0; |
| 531 | } |
| 532 | |
| 533 | return 1; |
| 534 | } |
| 535 | |
| 536 | /* We know we have a pipe buffer, but maybe it's empty? */ |
| 537 | static inline bool eat_empty_buffer(struct pipe_inode_info *pipe) |
| 538 | { |
| 539 | unsigned int tail = pipe->tail; |
| 540 | unsigned int mask = pipe->ring_size - 1; |
| 541 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 542 | |
| 543 | if (unlikely(!buf->len)) { |
| 544 | pipe_buf_release(pipe, buf); |
| 545 | pipe->tail = tail+1; |
| 546 | return true; |
| 547 | } |
| 548 | |
| 549 | return false; |
| 550 | } |
| 551 | |
| 552 | /** |
| 553 | * splice_from_pipe_next - wait for some data to splice from |
| 554 | * @pipe: pipe to splice from |
| 555 | * @sd: information about the splice operation |
| 556 | * |
| 557 | * Description: |
| 558 | * This function will wait for some data and return a positive |
| 559 | * value (one) if pipe buffers are available. It will return zero |
| 560 | * or -errno if no more data needs to be spliced. |
| 561 | */ |
| 562 | static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 563 | { |
| 564 | /* |
| 565 | * Check for signal early to make process killable when there are |
| 566 | * always buffers available |
| 567 | */ |
| 568 | if (signal_pending(current)) |
| 569 | return -ERESTARTSYS; |
| 570 | |
| 571 | repeat: |
| 572 | while (pipe_empty(pipe->head, pipe->tail)) { |
| 573 | if (!pipe->writers) |
| 574 | return 0; |
| 575 | |
| 576 | if (sd->num_spliced) |
| 577 | return 0; |
| 578 | |
| 579 | if (sd->flags & SPLICE_F_NONBLOCK) |
| 580 | return -EAGAIN; |
| 581 | |
| 582 | if (signal_pending(current)) |
| 583 | return -ERESTARTSYS; |
| 584 | |
| 585 | if (sd->need_wakeup) { |
| 586 | wakeup_pipe_writers(pipe); |
| 587 | sd->need_wakeup = false; |
| 588 | } |
| 589 | |
| 590 | pipe_wait_readable(pipe); |
| 591 | } |
| 592 | |
| 593 | if (eat_empty_buffer(pipe)) |
| 594 | goto repeat; |
| 595 | |
| 596 | return 1; |
| 597 | } |
| 598 | |
| 599 | /** |
| 600 | * splice_from_pipe_begin - start splicing from pipe |
| 601 | * @sd: information about the splice operation |
| 602 | * |
| 603 | * Description: |
| 604 | * This function should be called before a loop containing |
| 605 | * splice_from_pipe_next() and splice_from_pipe_feed() to |
| 606 | * initialize the necessary fields of @sd. |
| 607 | */ |
| 608 | static void splice_from_pipe_begin(struct splice_desc *sd) |
| 609 | { |
| 610 | sd->num_spliced = 0; |
| 611 | sd->need_wakeup = false; |
| 612 | } |
| 613 | |
| 614 | /** |
| 615 | * splice_from_pipe_end - finish splicing from pipe |
| 616 | * @pipe: pipe to splice from |
| 617 | * @sd: information about the splice operation |
| 618 | * |
| 619 | * Description: |
| 620 | * This function will wake up pipe writers if necessary. It should |
| 621 | * be called after a loop containing splice_from_pipe_next() and |
| 622 | * splice_from_pipe_feed(). |
| 623 | */ |
| 624 | static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 625 | { |
| 626 | if (sd->need_wakeup) |
| 627 | wakeup_pipe_writers(pipe); |
| 628 | } |
| 629 | |
| 630 | /** |
| 631 | * __splice_from_pipe - splice data from a pipe to given actor |
| 632 | * @pipe: pipe to splice from |
| 633 | * @sd: information to @actor |
| 634 | * @actor: handler that splices the data |
| 635 | * |
| 636 | * Description: |
| 637 | * This function does little more than loop over the pipe and call |
| 638 | * @actor to do the actual moving of a single struct pipe_buffer to |
| 639 | * the desired destination. See pipe_to_file, pipe_to_sendpage, or |
| 640 | * pipe_to_user. |
| 641 | * |
| 642 | */ |
| 643 | ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, |
| 644 | splice_actor *actor) |
| 645 | { |
| 646 | int ret; |
| 647 | |
| 648 | splice_from_pipe_begin(sd); |
| 649 | do { |
| 650 | cond_resched(); |
| 651 | ret = splice_from_pipe_next(pipe, sd); |
| 652 | if (ret > 0) |
| 653 | ret = splice_from_pipe_feed(pipe, sd, actor); |
| 654 | } while (ret > 0); |
| 655 | splice_from_pipe_end(pipe, sd); |
| 656 | |
| 657 | return sd->num_spliced ? sd->num_spliced : ret; |
| 658 | } |
| 659 | EXPORT_SYMBOL(__splice_from_pipe); |
| 660 | |
| 661 | /** |
| 662 | * splice_from_pipe - splice data from a pipe to a file |
| 663 | * @pipe: pipe to splice from |
| 664 | * @out: file to splice to |
| 665 | * @ppos: position in @out |
| 666 | * @len: how many bytes to splice |
| 667 | * @flags: splice modifier flags |
| 668 | * @actor: handler that splices the data |
| 669 | * |
| 670 | * Description: |
| 671 | * See __splice_from_pipe. This function locks the pipe inode, |
| 672 | * otherwise it's identical to __splice_from_pipe(). |
| 673 | * |
| 674 | */ |
| 675 | ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
| 676 | loff_t *ppos, size_t len, unsigned int flags, |
| 677 | splice_actor *actor) |
| 678 | { |
| 679 | ssize_t ret; |
| 680 | struct splice_desc sd = { |
| 681 | .total_len = len, |
| 682 | .flags = flags, |
| 683 | .pos = *ppos, |
| 684 | .u.file = out, |
| 685 | }; |
| 686 | |
| 687 | pipe_lock(pipe); |
| 688 | ret = __splice_from_pipe(pipe, &sd, actor); |
| 689 | pipe_unlock(pipe); |
| 690 | |
| 691 | return ret; |
| 692 | } |
| 693 | |
| 694 | /** |
| 695 | * iter_file_splice_write - splice data from a pipe to a file |
| 696 | * @pipe: pipe info |
| 697 | * @out: file to write to |
| 698 | * @ppos: position in @out |
| 699 | * @len: number of bytes to splice |
| 700 | * @flags: splice modifier flags |
| 701 | * |
| 702 | * Description: |
| 703 | * Will either move or copy pages (determined by @flags options) from |
| 704 | * the given pipe inode to the given file. |
| 705 | * This one is ->write_iter-based. |
| 706 | * |
| 707 | */ |
| 708 | ssize_t |
| 709 | iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, |
| 710 | loff_t *ppos, size_t len, unsigned int flags) |
| 711 | { |
| 712 | struct splice_desc sd = { |
| 713 | .total_len = len, |
| 714 | .flags = flags, |
| 715 | .pos = *ppos, |
| 716 | .u.file = out, |
| 717 | }; |
| 718 | int nbufs = pipe->max_usage; |
| 719 | struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), |
| 720 | GFP_KERNEL); |
| 721 | ssize_t ret; |
| 722 | |
| 723 | if (unlikely(!array)) |
| 724 | return -ENOMEM; |
| 725 | |
| 726 | pipe_lock(pipe); |
| 727 | |
| 728 | splice_from_pipe_begin(&sd); |
| 729 | while (sd.total_len) { |
| 730 | struct iov_iter from; |
| 731 | unsigned int head, tail, mask; |
| 732 | size_t left; |
| 733 | int n; |
| 734 | |
| 735 | ret = splice_from_pipe_next(pipe, &sd); |
| 736 | if (ret <= 0) |
| 737 | break; |
| 738 | |
| 739 | if (unlikely(nbufs < pipe->max_usage)) { |
| 740 | kfree(array); |
| 741 | nbufs = pipe->max_usage; |
| 742 | array = kcalloc(nbufs, sizeof(struct bio_vec), |
| 743 | GFP_KERNEL); |
| 744 | if (!array) { |
| 745 | ret = -ENOMEM; |
| 746 | break; |
| 747 | } |
| 748 | } |
| 749 | |
| 750 | head = pipe->head; |
| 751 | tail = pipe->tail; |
| 752 | mask = pipe->ring_size - 1; |
| 753 | |
| 754 | /* build the vector */ |
| 755 | left = sd.total_len; |
| 756 | for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { |
| 757 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 758 | size_t this_len = buf->len; |
| 759 | |
| 760 | /* zero-length bvecs are not supported, skip them */ |
| 761 | if (!this_len) |
| 762 | continue; |
| 763 | this_len = min(this_len, left); |
| 764 | |
| 765 | ret = pipe_buf_confirm(pipe, buf); |
| 766 | if (unlikely(ret)) { |
| 767 | if (ret == -ENODATA) |
| 768 | ret = 0; |
| 769 | goto done; |
| 770 | } |
| 771 | |
| 772 | bvec_set_page(&array[n], buf->page, this_len, |
| 773 | buf->offset); |
| 774 | left -= this_len; |
| 775 | n++; |
| 776 | } |
| 777 | |
| 778 | iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left); |
| 779 | ret = vfs_iter_write(out, &from, &sd.pos, 0); |
| 780 | if (ret <= 0) |
| 781 | break; |
| 782 | |
| 783 | sd.num_spliced += ret; |
| 784 | sd.total_len -= ret; |
| 785 | *ppos = sd.pos; |
| 786 | |
| 787 | /* dismiss the fully eaten buffers, adjust the partial one */ |
| 788 | tail = pipe->tail; |
| 789 | while (ret) { |
| 790 | struct pipe_buffer *buf = &pipe->bufs[tail & mask]; |
| 791 | if (ret >= buf->len) { |
| 792 | ret -= buf->len; |
| 793 | buf->len = 0; |
| 794 | pipe_buf_release(pipe, buf); |
| 795 | tail++; |
| 796 | pipe->tail = tail; |
| 797 | if (pipe->files) |
| 798 | sd.need_wakeup = true; |
| 799 | } else { |
| 800 | buf->offset += ret; |
| 801 | buf->len -= ret; |
| 802 | ret = 0; |
| 803 | } |
| 804 | } |
| 805 | } |
| 806 | done: |
| 807 | kfree(array); |
| 808 | splice_from_pipe_end(pipe, &sd); |
| 809 | |
| 810 | pipe_unlock(pipe); |
| 811 | |
| 812 | if (sd.num_spliced) |
| 813 | ret = sd.num_spliced; |
| 814 | |
| 815 | return ret; |
| 816 | } |
| 817 | |
| 818 | EXPORT_SYMBOL(iter_file_splice_write); |
| 819 | |
| 820 | /** |
| 821 | * generic_splice_sendpage - splice data from a pipe to a socket |
| 822 | * @pipe: pipe to splice from |
| 823 | * @out: socket to write to |
| 824 | * @ppos: position in @out |
| 825 | * @len: number of bytes to splice |
| 826 | * @flags: splice modifier flags |
| 827 | * |
| 828 | * Description: |
| 829 | * Will send @len bytes from the pipe to a network socket. No data copying |
| 830 | * is involved. |
| 831 | * |
| 832 | */ |
| 833 | ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, |
| 834 | loff_t *ppos, size_t len, unsigned int flags) |
| 835 | { |
| 836 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); |
| 837 | } |
| 838 | |
| 839 | EXPORT_SYMBOL(generic_splice_sendpage); |
| 840 | |
| 841 | static int warn_unsupported(struct file *file, const char *op) |
| 842 | { |
| 843 | pr_debug_ratelimited( |
| 844 | "splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n", |
| 845 | op, file, current->pid, current->comm); |
| 846 | return -EINVAL; |
| 847 | } |
| 848 | |
| 849 | /* |
| 850 | * Attempt to initiate a splice from pipe to file. |
| 851 | */ |
| 852 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
| 853 | loff_t *ppos, size_t len, unsigned int flags) |
| 854 | { |
| 855 | if (unlikely(!out->f_op->splice_write)) |
| 856 | return warn_unsupported(out, "write"); |
| 857 | return out->f_op->splice_write(pipe, out, ppos, len, flags); |
| 858 | } |
| 859 | |
| 860 | /* |
| 861 | * Attempt to initiate a splice from a file to a pipe. |
| 862 | */ |
| 863 | static long do_splice_to(struct file *in, loff_t *ppos, |
| 864 | struct pipe_inode_info *pipe, size_t len, |
| 865 | unsigned int flags) |
| 866 | { |
| 867 | unsigned int p_space; |
| 868 | int ret; |
| 869 | |
| 870 | if (unlikely(!(in->f_mode & FMODE_READ))) |
| 871 | return -EBADF; |
| 872 | |
| 873 | /* Don't try to read more the pipe has space for. */ |
| 874 | p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail); |
| 875 | len = min_t(size_t, len, p_space << PAGE_SHIFT); |
| 876 | |
| 877 | ret = rw_verify_area(READ, in, ppos, len); |
| 878 | if (unlikely(ret < 0)) |
| 879 | return ret; |
| 880 | |
| 881 | if (unlikely(len > MAX_RW_COUNT)) |
| 882 | len = MAX_RW_COUNT; |
| 883 | |
| 884 | if (unlikely(!in->f_op->splice_read)) |
| 885 | return warn_unsupported(in, "read"); |
| 886 | return in->f_op->splice_read(in, ppos, pipe, len, flags); |
| 887 | } |
| 888 | |
| 889 | /** |
| 890 | * splice_direct_to_actor - splices data directly between two non-pipes |
| 891 | * @in: file to splice from |
| 892 | * @sd: actor information on where to splice to |
| 893 | * @actor: handles the data splicing |
| 894 | * |
| 895 | * Description: |
| 896 | * This is a special case helper to splice directly between two |
| 897 | * points, without requiring an explicit pipe. Internally an allocated |
| 898 | * pipe is cached in the process, and reused during the lifetime of |
| 899 | * that process. |
| 900 | * |
| 901 | */ |
| 902 | ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, |
| 903 | splice_direct_actor *actor) |
| 904 | { |
| 905 | struct pipe_inode_info *pipe; |
| 906 | long ret, bytes; |
| 907 | size_t len; |
| 908 | int i, flags, more; |
| 909 | |
| 910 | /* |
| 911 | * We require the input to be seekable, as we don't want to randomly |
| 912 | * drop data for eg socket -> socket splicing. Use the piped splicing |
| 913 | * for that! |
| 914 | */ |
| 915 | if (unlikely(!(in->f_mode & FMODE_LSEEK))) |
| 916 | return -EINVAL; |
| 917 | |
| 918 | /* |
| 919 | * neither in nor out is a pipe, setup an internal pipe attached to |
| 920 | * 'out' and transfer the wanted data from 'in' to 'out' through that |
| 921 | */ |
| 922 | pipe = current->splice_pipe; |
| 923 | if (unlikely(!pipe)) { |
| 924 | pipe = alloc_pipe_info(); |
| 925 | if (!pipe) |
| 926 | return -ENOMEM; |
| 927 | |
| 928 | /* |
| 929 | * We don't have an immediate reader, but we'll read the stuff |
| 930 | * out of the pipe right after the splice_to_pipe(). So set |
| 931 | * PIPE_READERS appropriately. |
| 932 | */ |
| 933 | pipe->readers = 1; |
| 934 | |
| 935 | current->splice_pipe = pipe; |
| 936 | } |
| 937 | |
| 938 | /* |
| 939 | * Do the splice. |
| 940 | */ |
| 941 | bytes = 0; |
| 942 | len = sd->total_len; |
| 943 | flags = sd->flags; |
| 944 | |
| 945 | /* |
| 946 | * Don't block on output, we have to drain the direct pipe. |
| 947 | */ |
| 948 | sd->flags &= ~SPLICE_F_NONBLOCK; |
| 949 | more = sd->flags & SPLICE_F_MORE; |
| 950 | |
| 951 | WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail)); |
| 952 | |
| 953 | while (len) { |
| 954 | size_t read_len; |
| 955 | loff_t pos = sd->pos, prev_pos = pos; |
| 956 | |
| 957 | ret = do_splice_to(in, &pos, pipe, len, flags); |
| 958 | if (unlikely(ret <= 0)) |
| 959 | goto out_release; |
| 960 | |
| 961 | read_len = ret; |
| 962 | sd->total_len = read_len; |
| 963 | |
| 964 | /* |
| 965 | * If more data is pending, set SPLICE_F_MORE |
| 966 | * If this is the last data and SPLICE_F_MORE was not set |
| 967 | * initially, clears it. |
| 968 | */ |
| 969 | if (read_len < len) |
| 970 | sd->flags |= SPLICE_F_MORE; |
| 971 | else if (!more) |
| 972 | sd->flags &= ~SPLICE_F_MORE; |
| 973 | /* |
| 974 | * NOTE: nonblocking mode only applies to the input. We |
| 975 | * must not do the output in nonblocking mode as then we |
| 976 | * could get stuck data in the internal pipe: |
| 977 | */ |
| 978 | ret = actor(pipe, sd); |
| 979 | if (unlikely(ret <= 0)) { |
| 980 | sd->pos = prev_pos; |
| 981 | goto out_release; |
| 982 | } |
| 983 | |
| 984 | bytes += ret; |
| 985 | len -= ret; |
| 986 | sd->pos = pos; |
| 987 | |
| 988 | if (ret < read_len) { |
| 989 | sd->pos = prev_pos + ret; |
| 990 | goto out_release; |
| 991 | } |
| 992 | } |
| 993 | |
| 994 | done: |
| 995 | pipe->tail = pipe->head = 0; |
| 996 | file_accessed(in); |
| 997 | return bytes; |
| 998 | |
| 999 | out_release: |
| 1000 | /* |
| 1001 | * If we did an incomplete transfer we must release |
| 1002 | * the pipe buffers in question: |
| 1003 | */ |
| 1004 | for (i = 0; i < pipe->ring_size; i++) { |
| 1005 | struct pipe_buffer *buf = &pipe->bufs[i]; |
| 1006 | |
| 1007 | if (buf->ops) |
| 1008 | pipe_buf_release(pipe, buf); |
| 1009 | } |
| 1010 | |
| 1011 | if (!bytes) |
| 1012 | bytes = ret; |
| 1013 | |
| 1014 | goto done; |
| 1015 | } |
| 1016 | EXPORT_SYMBOL(splice_direct_to_actor); |
| 1017 | |
| 1018 | static int direct_splice_actor(struct pipe_inode_info *pipe, |
| 1019 | struct splice_desc *sd) |
| 1020 | { |
| 1021 | struct file *file = sd->u.file; |
| 1022 | |
| 1023 | return do_splice_from(pipe, file, sd->opos, sd->total_len, |
| 1024 | sd->flags); |
| 1025 | } |
| 1026 | |
| 1027 | /** |
| 1028 | * do_splice_direct - splices data directly between two files |
| 1029 | * @in: file to splice from |
| 1030 | * @ppos: input file offset |
| 1031 | * @out: file to splice to |
| 1032 | * @opos: output file offset |
| 1033 | * @len: number of bytes to splice |
| 1034 | * @flags: splice modifier flags |
| 1035 | * |
| 1036 | * Description: |
| 1037 | * For use by do_sendfile(). splice can easily emulate sendfile, but |
| 1038 | * doing it in the application would incur an extra system call |
| 1039 | * (splice in + splice out, as compared to just sendfile()). So this helper |
| 1040 | * can splice directly through a process-private pipe. |
| 1041 | * |
| 1042 | */ |
| 1043 | long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, |
| 1044 | loff_t *opos, size_t len, unsigned int flags) |
| 1045 | { |
| 1046 | struct splice_desc sd = { |
| 1047 | .len = len, |
| 1048 | .total_len = len, |
| 1049 | .flags = flags, |
| 1050 | .pos = *ppos, |
| 1051 | .u.file = out, |
| 1052 | .opos = opos, |
| 1053 | }; |
| 1054 | long ret; |
| 1055 | |
| 1056 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
| 1057 | return -EBADF; |
| 1058 | |
| 1059 | if (unlikely(out->f_flags & O_APPEND)) |
| 1060 | return -EINVAL; |
| 1061 | |
| 1062 | ret = rw_verify_area(WRITE, out, opos, len); |
| 1063 | if (unlikely(ret < 0)) |
| 1064 | return ret; |
| 1065 | |
| 1066 | ret = splice_direct_to_actor(in, &sd, direct_splice_actor); |
| 1067 | if (ret > 0) |
| 1068 | *ppos = sd.pos; |
| 1069 | |
| 1070 | return ret; |
| 1071 | } |
| 1072 | EXPORT_SYMBOL(do_splice_direct); |
| 1073 | |
| 1074 | static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) |
| 1075 | { |
| 1076 | for (;;) { |
| 1077 | if (unlikely(!pipe->readers)) { |
| 1078 | send_sig(SIGPIPE, current, 0); |
| 1079 | return -EPIPE; |
| 1080 | } |
| 1081 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
| 1082 | return 0; |
| 1083 | if (flags & SPLICE_F_NONBLOCK) |
| 1084 | return -EAGAIN; |
| 1085 | if (signal_pending(current)) |
| 1086 | return -ERESTARTSYS; |
| 1087 | pipe_wait_writable(pipe); |
| 1088 | } |
| 1089 | } |
| 1090 | |
| 1091 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1092 | struct pipe_inode_info *opipe, |
| 1093 | size_t len, unsigned int flags); |
| 1094 | |
| 1095 | long splice_file_to_pipe(struct file *in, |
| 1096 | struct pipe_inode_info *opipe, |
| 1097 | loff_t *offset, |
| 1098 | size_t len, unsigned int flags) |
| 1099 | { |
| 1100 | long ret; |
| 1101 | |
| 1102 | pipe_lock(opipe); |
| 1103 | ret = wait_for_space(opipe, flags); |
| 1104 | if (!ret) |
| 1105 | ret = do_splice_to(in, offset, opipe, len, flags); |
| 1106 | pipe_unlock(opipe); |
| 1107 | if (ret > 0) |
| 1108 | wakeup_pipe_readers(opipe); |
| 1109 | return ret; |
| 1110 | } |
| 1111 | |
| 1112 | /* |
| 1113 | * Determine where to splice to/from. |
| 1114 | */ |
| 1115 | long do_splice(struct file *in, loff_t *off_in, struct file *out, |
| 1116 | loff_t *off_out, size_t len, unsigned int flags) |
| 1117 | { |
| 1118 | struct pipe_inode_info *ipipe; |
| 1119 | struct pipe_inode_info *opipe; |
| 1120 | loff_t offset; |
| 1121 | long ret; |
| 1122 | |
| 1123 | if (unlikely(!(in->f_mode & FMODE_READ) || |
| 1124 | !(out->f_mode & FMODE_WRITE))) |
| 1125 | return -EBADF; |
| 1126 | |
| 1127 | ipipe = get_pipe_info(in, true); |
| 1128 | opipe = get_pipe_info(out, true); |
| 1129 | |
| 1130 | if (ipipe && opipe) { |
| 1131 | if (off_in || off_out) |
| 1132 | return -ESPIPE; |
| 1133 | |
| 1134 | /* Splicing to self would be fun, but... */ |
| 1135 | if (ipipe == opipe) |
| 1136 | return -EINVAL; |
| 1137 | |
| 1138 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
| 1139 | flags |= SPLICE_F_NONBLOCK; |
| 1140 | |
| 1141 | return splice_pipe_to_pipe(ipipe, opipe, len, flags); |
| 1142 | } |
| 1143 | |
| 1144 | if (ipipe) { |
| 1145 | if (off_in) |
| 1146 | return -ESPIPE; |
| 1147 | if (off_out) { |
| 1148 | if (!(out->f_mode & FMODE_PWRITE)) |
| 1149 | return -EINVAL; |
| 1150 | offset = *off_out; |
| 1151 | } else { |
| 1152 | offset = out->f_pos; |
| 1153 | } |
| 1154 | |
| 1155 | if (unlikely(out->f_flags & O_APPEND)) |
| 1156 | return -EINVAL; |
| 1157 | |
| 1158 | ret = rw_verify_area(WRITE, out, &offset, len); |
| 1159 | if (unlikely(ret < 0)) |
| 1160 | return ret; |
| 1161 | |
| 1162 | if (in->f_flags & O_NONBLOCK) |
| 1163 | flags |= SPLICE_F_NONBLOCK; |
| 1164 | |
| 1165 | file_start_write(out); |
| 1166 | ret = do_splice_from(ipipe, out, &offset, len, flags); |
| 1167 | file_end_write(out); |
| 1168 | |
| 1169 | if (ret > 0) |
| 1170 | fsnotify_modify(out); |
| 1171 | |
| 1172 | if (!off_out) |
| 1173 | out->f_pos = offset; |
| 1174 | else |
| 1175 | *off_out = offset; |
| 1176 | |
| 1177 | return ret; |
| 1178 | } |
| 1179 | |
| 1180 | if (opipe) { |
| 1181 | if (off_out) |
| 1182 | return -ESPIPE; |
| 1183 | if (off_in) { |
| 1184 | if (!(in->f_mode & FMODE_PREAD)) |
| 1185 | return -EINVAL; |
| 1186 | offset = *off_in; |
| 1187 | } else { |
| 1188 | offset = in->f_pos; |
| 1189 | } |
| 1190 | |
| 1191 | if (out->f_flags & O_NONBLOCK) |
| 1192 | flags |= SPLICE_F_NONBLOCK; |
| 1193 | |
| 1194 | ret = splice_file_to_pipe(in, opipe, &offset, len, flags); |
| 1195 | |
| 1196 | if (ret > 0) |
| 1197 | fsnotify_access(in); |
| 1198 | |
| 1199 | if (!off_in) |
| 1200 | in->f_pos = offset; |
| 1201 | else |
| 1202 | *off_in = offset; |
| 1203 | |
| 1204 | return ret; |
| 1205 | } |
| 1206 | |
| 1207 | return -EINVAL; |
| 1208 | } |
| 1209 | |
| 1210 | static long __do_splice(struct file *in, loff_t __user *off_in, |
| 1211 | struct file *out, loff_t __user *off_out, |
| 1212 | size_t len, unsigned int flags) |
| 1213 | { |
| 1214 | struct pipe_inode_info *ipipe; |
| 1215 | struct pipe_inode_info *opipe; |
| 1216 | loff_t offset, *__off_in = NULL, *__off_out = NULL; |
| 1217 | long ret; |
| 1218 | |
| 1219 | ipipe = get_pipe_info(in, true); |
| 1220 | opipe = get_pipe_info(out, true); |
| 1221 | |
| 1222 | if (ipipe && off_in) |
| 1223 | return -ESPIPE; |
| 1224 | if (opipe && off_out) |
| 1225 | return -ESPIPE; |
| 1226 | |
| 1227 | if (off_out) { |
| 1228 | if (copy_from_user(&offset, off_out, sizeof(loff_t))) |
| 1229 | return -EFAULT; |
| 1230 | __off_out = &offset; |
| 1231 | } |
| 1232 | if (off_in) { |
| 1233 | if (copy_from_user(&offset, off_in, sizeof(loff_t))) |
| 1234 | return -EFAULT; |
| 1235 | __off_in = &offset; |
| 1236 | } |
| 1237 | |
| 1238 | ret = do_splice(in, __off_in, out, __off_out, len, flags); |
| 1239 | if (ret < 0) |
| 1240 | return ret; |
| 1241 | |
| 1242 | if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t))) |
| 1243 | return -EFAULT; |
| 1244 | if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t))) |
| 1245 | return -EFAULT; |
| 1246 | |
| 1247 | return ret; |
| 1248 | } |
| 1249 | |
| 1250 | static int iter_to_pipe(struct iov_iter *from, |
| 1251 | struct pipe_inode_info *pipe, |
| 1252 | unsigned flags) |
| 1253 | { |
| 1254 | struct pipe_buffer buf = { |
| 1255 | .ops = &user_page_pipe_buf_ops, |
| 1256 | .flags = flags |
| 1257 | }; |
| 1258 | size_t total = 0; |
| 1259 | int ret = 0; |
| 1260 | |
| 1261 | while (iov_iter_count(from)) { |
| 1262 | struct page *pages[16]; |
| 1263 | ssize_t left; |
| 1264 | size_t start; |
| 1265 | int i, n; |
| 1266 | |
| 1267 | left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); |
| 1268 | if (left <= 0) { |
| 1269 | ret = left; |
| 1270 | break; |
| 1271 | } |
| 1272 | |
| 1273 | n = DIV_ROUND_UP(left + start, PAGE_SIZE); |
| 1274 | for (i = 0; i < n; i++) { |
| 1275 | int size = min_t(int, left, PAGE_SIZE - start); |
| 1276 | |
| 1277 | buf.page = pages[i]; |
| 1278 | buf.offset = start; |
| 1279 | buf.len = size; |
| 1280 | ret = add_to_pipe(pipe, &buf); |
| 1281 | if (unlikely(ret < 0)) { |
| 1282 | iov_iter_revert(from, left); |
| 1283 | // this one got dropped by add_to_pipe() |
| 1284 | while (++i < n) |
| 1285 | put_page(pages[i]); |
| 1286 | goto out; |
| 1287 | } |
| 1288 | total += ret; |
| 1289 | left -= size; |
| 1290 | start = 0; |
| 1291 | } |
| 1292 | } |
| 1293 | out: |
| 1294 | return total ? total : ret; |
| 1295 | } |
| 1296 | |
| 1297 | static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 1298 | struct splice_desc *sd) |
| 1299 | { |
| 1300 | int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data); |
| 1301 | return n == sd->len ? n : -EFAULT; |
| 1302 | } |
| 1303 | |
| 1304 | /* |
| 1305 | * For lack of a better implementation, implement vmsplice() to userspace |
| 1306 | * as a simple copy of the pipes pages to the user iov. |
| 1307 | */ |
| 1308 | static long vmsplice_to_user(struct file *file, struct iov_iter *iter, |
| 1309 | unsigned int flags) |
| 1310 | { |
| 1311 | struct pipe_inode_info *pipe = get_pipe_info(file, true); |
| 1312 | struct splice_desc sd = { |
| 1313 | .total_len = iov_iter_count(iter), |
| 1314 | .flags = flags, |
| 1315 | .u.data = iter |
| 1316 | }; |
| 1317 | long ret = 0; |
| 1318 | |
| 1319 | if (!pipe) |
| 1320 | return -EBADF; |
| 1321 | |
| 1322 | if (sd.total_len) { |
| 1323 | pipe_lock(pipe); |
| 1324 | ret = __splice_from_pipe(pipe, &sd, pipe_to_user); |
| 1325 | pipe_unlock(pipe); |
| 1326 | } |
| 1327 | |
| 1328 | return ret; |
| 1329 | } |
| 1330 | |
| 1331 | /* |
| 1332 | * vmsplice splices a user address range into a pipe. It can be thought of |
| 1333 | * as splice-from-memory, where the regular splice is splice-from-file (or |
| 1334 | * to file). In both cases the output is a pipe, naturally. |
| 1335 | */ |
| 1336 | static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter, |
| 1337 | unsigned int flags) |
| 1338 | { |
| 1339 | struct pipe_inode_info *pipe; |
| 1340 | long ret = 0; |
| 1341 | unsigned buf_flag = 0; |
| 1342 | |
| 1343 | if (flags & SPLICE_F_GIFT) |
| 1344 | buf_flag = PIPE_BUF_FLAG_GIFT; |
| 1345 | |
| 1346 | pipe = get_pipe_info(file, true); |
| 1347 | if (!pipe) |
| 1348 | return -EBADF; |
| 1349 | |
| 1350 | pipe_lock(pipe); |
| 1351 | ret = wait_for_space(pipe, flags); |
| 1352 | if (!ret) |
| 1353 | ret = iter_to_pipe(iter, pipe, buf_flag); |
| 1354 | pipe_unlock(pipe); |
| 1355 | if (ret > 0) |
| 1356 | wakeup_pipe_readers(pipe); |
| 1357 | return ret; |
| 1358 | } |
| 1359 | |
| 1360 | static int vmsplice_type(struct fd f, int *type) |
| 1361 | { |
| 1362 | if (!f.file) |
| 1363 | return -EBADF; |
| 1364 | if (f.file->f_mode & FMODE_WRITE) { |
| 1365 | *type = ITER_SOURCE; |
| 1366 | } else if (f.file->f_mode & FMODE_READ) { |
| 1367 | *type = ITER_DEST; |
| 1368 | } else { |
| 1369 | fdput(f); |
| 1370 | return -EBADF; |
| 1371 | } |
| 1372 | return 0; |
| 1373 | } |
| 1374 | |
| 1375 | /* |
| 1376 | * Note that vmsplice only really supports true splicing _from_ user memory |
| 1377 | * to a pipe, not the other way around. Splicing from user memory is a simple |
| 1378 | * operation that can be supported without any funky alignment restrictions |
| 1379 | * or nasty vm tricks. We simply map in the user memory and fill them into |
| 1380 | * a pipe. The reverse isn't quite as easy, though. There are two possible |
| 1381 | * solutions for that: |
| 1382 | * |
| 1383 | * - memcpy() the data internally, at which point we might as well just |
| 1384 | * do a regular read() on the buffer anyway. |
| 1385 | * - Lots of nasty vm tricks, that are neither fast nor flexible (it |
| 1386 | * has restriction limitations on both ends of the pipe). |
| 1387 | * |
| 1388 | * Currently we punt and implement it as a normal copy, see pipe_to_user(). |
| 1389 | * |
| 1390 | */ |
| 1391 | SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov, |
| 1392 | unsigned long, nr_segs, unsigned int, flags) |
| 1393 | { |
| 1394 | struct iovec iovstack[UIO_FASTIOV]; |
| 1395 | struct iovec *iov = iovstack; |
| 1396 | struct iov_iter iter; |
| 1397 | ssize_t error; |
| 1398 | struct fd f; |
| 1399 | int type; |
| 1400 | |
| 1401 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 1402 | return -EINVAL; |
| 1403 | |
| 1404 | f = fdget(fd); |
| 1405 | error = vmsplice_type(f, &type); |
| 1406 | if (error) |
| 1407 | return error; |
| 1408 | |
| 1409 | error = import_iovec(type, uiov, nr_segs, |
| 1410 | ARRAY_SIZE(iovstack), &iov, &iter); |
| 1411 | if (error < 0) |
| 1412 | goto out_fdput; |
| 1413 | |
| 1414 | if (!iov_iter_count(&iter)) |
| 1415 | error = 0; |
| 1416 | else if (type == ITER_SOURCE) |
| 1417 | error = vmsplice_to_pipe(f.file, &iter, flags); |
| 1418 | else |
| 1419 | error = vmsplice_to_user(f.file, &iter, flags); |
| 1420 | |
| 1421 | kfree(iov); |
| 1422 | out_fdput: |
| 1423 | fdput(f); |
| 1424 | return error; |
| 1425 | } |
| 1426 | |
| 1427 | SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in, |
| 1428 | int, fd_out, loff_t __user *, off_out, |
| 1429 | size_t, len, unsigned int, flags) |
| 1430 | { |
| 1431 | struct fd in, out; |
| 1432 | long error; |
| 1433 | |
| 1434 | if (unlikely(!len)) |
| 1435 | return 0; |
| 1436 | |
| 1437 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 1438 | return -EINVAL; |
| 1439 | |
| 1440 | error = -EBADF; |
| 1441 | in = fdget(fd_in); |
| 1442 | if (in.file) { |
| 1443 | out = fdget(fd_out); |
| 1444 | if (out.file) { |
| 1445 | error = __do_splice(in.file, off_in, out.file, off_out, |
| 1446 | len, flags); |
| 1447 | fdput(out); |
| 1448 | } |
| 1449 | fdput(in); |
| 1450 | } |
| 1451 | return error; |
| 1452 | } |
| 1453 | |
| 1454 | /* |
| 1455 | * Make sure there's data to read. Wait for input if we can, otherwise |
| 1456 | * return an appropriate error. |
| 1457 | */ |
| 1458 | static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1459 | { |
| 1460 | int ret; |
| 1461 | |
| 1462 | /* |
| 1463 | * Check the pipe occupancy without the inode lock first. This function |
| 1464 | * is speculative anyways, so missing one is ok. |
| 1465 | */ |
| 1466 | if (!pipe_empty(pipe->head, pipe->tail)) |
| 1467 | return 0; |
| 1468 | |
| 1469 | ret = 0; |
| 1470 | pipe_lock(pipe); |
| 1471 | |
| 1472 | while (pipe_empty(pipe->head, pipe->tail)) { |
| 1473 | if (signal_pending(current)) { |
| 1474 | ret = -ERESTARTSYS; |
| 1475 | break; |
| 1476 | } |
| 1477 | if (!pipe->writers) |
| 1478 | break; |
| 1479 | if (flags & SPLICE_F_NONBLOCK) { |
| 1480 | ret = -EAGAIN; |
| 1481 | break; |
| 1482 | } |
| 1483 | pipe_wait_readable(pipe); |
| 1484 | } |
| 1485 | |
| 1486 | pipe_unlock(pipe); |
| 1487 | return ret; |
| 1488 | } |
| 1489 | |
| 1490 | /* |
| 1491 | * Make sure there's writeable room. Wait for room if we can, otherwise |
| 1492 | * return an appropriate error. |
| 1493 | */ |
| 1494 | static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags) |
| 1495 | { |
| 1496 | int ret; |
| 1497 | |
| 1498 | /* |
| 1499 | * Check pipe occupancy without the inode lock first. This function |
| 1500 | * is speculative anyways, so missing one is ok. |
| 1501 | */ |
| 1502 | if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) |
| 1503 | return 0; |
| 1504 | |
| 1505 | ret = 0; |
| 1506 | pipe_lock(pipe); |
| 1507 | |
| 1508 | while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { |
| 1509 | if (!pipe->readers) { |
| 1510 | send_sig(SIGPIPE, current, 0); |
| 1511 | ret = -EPIPE; |
| 1512 | break; |
| 1513 | } |
| 1514 | if (flags & SPLICE_F_NONBLOCK) { |
| 1515 | ret = -EAGAIN; |
| 1516 | break; |
| 1517 | } |
| 1518 | if (signal_pending(current)) { |
| 1519 | ret = -ERESTARTSYS; |
| 1520 | break; |
| 1521 | } |
| 1522 | pipe_wait_writable(pipe); |
| 1523 | } |
| 1524 | |
| 1525 | pipe_unlock(pipe); |
| 1526 | return ret; |
| 1527 | } |
| 1528 | |
| 1529 | /* |
| 1530 | * Splice contents of ipipe to opipe. |
| 1531 | */ |
| 1532 | static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, |
| 1533 | struct pipe_inode_info *opipe, |
| 1534 | size_t len, unsigned int flags) |
| 1535 | { |
| 1536 | struct pipe_buffer *ibuf, *obuf; |
| 1537 | unsigned int i_head, o_head; |
| 1538 | unsigned int i_tail, o_tail; |
| 1539 | unsigned int i_mask, o_mask; |
| 1540 | int ret = 0; |
| 1541 | bool input_wakeup = false; |
| 1542 | |
| 1543 | |
| 1544 | retry: |
| 1545 | ret = ipipe_prep(ipipe, flags); |
| 1546 | if (ret) |
| 1547 | return ret; |
| 1548 | |
| 1549 | ret = opipe_prep(opipe, flags); |
| 1550 | if (ret) |
| 1551 | return ret; |
| 1552 | |
| 1553 | /* |
| 1554 | * Potential ABBA deadlock, work around it by ordering lock |
| 1555 | * grabbing by pipe info address. Otherwise two different processes |
| 1556 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1557 | */ |
| 1558 | pipe_double_lock(ipipe, opipe); |
| 1559 | |
| 1560 | i_tail = ipipe->tail; |
| 1561 | i_mask = ipipe->ring_size - 1; |
| 1562 | o_head = opipe->head; |
| 1563 | o_mask = opipe->ring_size - 1; |
| 1564 | |
| 1565 | do { |
| 1566 | size_t o_len; |
| 1567 | |
| 1568 | if (!opipe->readers) { |
| 1569 | send_sig(SIGPIPE, current, 0); |
| 1570 | if (!ret) |
| 1571 | ret = -EPIPE; |
| 1572 | break; |
| 1573 | } |
| 1574 | |
| 1575 | i_head = ipipe->head; |
| 1576 | o_tail = opipe->tail; |
| 1577 | |
| 1578 | if (pipe_empty(i_head, i_tail) && !ipipe->writers) |
| 1579 | break; |
| 1580 | |
| 1581 | /* |
| 1582 | * Cannot make any progress, because either the input |
| 1583 | * pipe is empty or the output pipe is full. |
| 1584 | */ |
| 1585 | if (pipe_empty(i_head, i_tail) || |
| 1586 | pipe_full(o_head, o_tail, opipe->max_usage)) { |
| 1587 | /* Already processed some buffers, break */ |
| 1588 | if (ret) |
| 1589 | break; |
| 1590 | |
| 1591 | if (flags & SPLICE_F_NONBLOCK) { |
| 1592 | ret = -EAGAIN; |
| 1593 | break; |
| 1594 | } |
| 1595 | |
| 1596 | /* |
| 1597 | * We raced with another reader/writer and haven't |
| 1598 | * managed to process any buffers. A zero return |
| 1599 | * value means EOF, so retry instead. |
| 1600 | */ |
| 1601 | pipe_unlock(ipipe); |
| 1602 | pipe_unlock(opipe); |
| 1603 | goto retry; |
| 1604 | } |
| 1605 | |
| 1606 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
| 1607 | obuf = &opipe->bufs[o_head & o_mask]; |
| 1608 | |
| 1609 | if (len >= ibuf->len) { |
| 1610 | /* |
| 1611 | * Simply move the whole buffer from ipipe to opipe |
| 1612 | */ |
| 1613 | *obuf = *ibuf; |
| 1614 | ibuf->ops = NULL; |
| 1615 | i_tail++; |
| 1616 | ipipe->tail = i_tail; |
| 1617 | input_wakeup = true; |
| 1618 | o_len = obuf->len; |
| 1619 | o_head++; |
| 1620 | opipe->head = o_head; |
| 1621 | } else { |
| 1622 | /* |
| 1623 | * Get a reference to this pipe buffer, |
| 1624 | * so we can copy the contents over. |
| 1625 | */ |
| 1626 | if (!pipe_buf_get(ipipe, ibuf)) { |
| 1627 | if (ret == 0) |
| 1628 | ret = -EFAULT; |
| 1629 | break; |
| 1630 | } |
| 1631 | *obuf = *ibuf; |
| 1632 | |
| 1633 | /* |
| 1634 | * Don't inherit the gift and merge flags, we need to |
| 1635 | * prevent multiple steals of this page. |
| 1636 | */ |
| 1637 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1638 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
| 1639 | |
| 1640 | obuf->len = len; |
| 1641 | ibuf->offset += len; |
| 1642 | ibuf->len -= len; |
| 1643 | o_len = len; |
| 1644 | o_head++; |
| 1645 | opipe->head = o_head; |
| 1646 | } |
| 1647 | ret += o_len; |
| 1648 | len -= o_len; |
| 1649 | } while (len); |
| 1650 | |
| 1651 | pipe_unlock(ipipe); |
| 1652 | pipe_unlock(opipe); |
| 1653 | |
| 1654 | /* |
| 1655 | * If we put data in the output pipe, wakeup any potential readers. |
| 1656 | */ |
| 1657 | if (ret > 0) |
| 1658 | wakeup_pipe_readers(opipe); |
| 1659 | |
| 1660 | if (input_wakeup) |
| 1661 | wakeup_pipe_writers(ipipe); |
| 1662 | |
| 1663 | return ret; |
| 1664 | } |
| 1665 | |
| 1666 | /* |
| 1667 | * Link contents of ipipe to opipe. |
| 1668 | */ |
| 1669 | static int link_pipe(struct pipe_inode_info *ipipe, |
| 1670 | struct pipe_inode_info *opipe, |
| 1671 | size_t len, unsigned int flags) |
| 1672 | { |
| 1673 | struct pipe_buffer *ibuf, *obuf; |
| 1674 | unsigned int i_head, o_head; |
| 1675 | unsigned int i_tail, o_tail; |
| 1676 | unsigned int i_mask, o_mask; |
| 1677 | int ret = 0; |
| 1678 | |
| 1679 | /* |
| 1680 | * Potential ABBA deadlock, work around it by ordering lock |
| 1681 | * grabbing by pipe info address. Otherwise two different processes |
| 1682 | * could deadlock (one doing tee from A -> B, the other from B -> A). |
| 1683 | */ |
| 1684 | pipe_double_lock(ipipe, opipe); |
| 1685 | |
| 1686 | i_tail = ipipe->tail; |
| 1687 | i_mask = ipipe->ring_size - 1; |
| 1688 | o_head = opipe->head; |
| 1689 | o_mask = opipe->ring_size - 1; |
| 1690 | |
| 1691 | do { |
| 1692 | if (!opipe->readers) { |
| 1693 | send_sig(SIGPIPE, current, 0); |
| 1694 | if (!ret) |
| 1695 | ret = -EPIPE; |
| 1696 | break; |
| 1697 | } |
| 1698 | |
| 1699 | i_head = ipipe->head; |
| 1700 | o_tail = opipe->tail; |
| 1701 | |
| 1702 | /* |
| 1703 | * If we have iterated all input buffers or run out of |
| 1704 | * output room, break. |
| 1705 | */ |
| 1706 | if (pipe_empty(i_head, i_tail) || |
| 1707 | pipe_full(o_head, o_tail, opipe->max_usage)) |
| 1708 | break; |
| 1709 | |
| 1710 | ibuf = &ipipe->bufs[i_tail & i_mask]; |
| 1711 | obuf = &opipe->bufs[o_head & o_mask]; |
| 1712 | |
| 1713 | /* |
| 1714 | * Get a reference to this pipe buffer, |
| 1715 | * so we can copy the contents over. |
| 1716 | */ |
| 1717 | if (!pipe_buf_get(ipipe, ibuf)) { |
| 1718 | if (ret == 0) |
| 1719 | ret = -EFAULT; |
| 1720 | break; |
| 1721 | } |
| 1722 | |
| 1723 | *obuf = *ibuf; |
| 1724 | |
| 1725 | /* |
| 1726 | * Don't inherit the gift and merge flag, we need to prevent |
| 1727 | * multiple steals of this page. |
| 1728 | */ |
| 1729 | obuf->flags &= ~PIPE_BUF_FLAG_GIFT; |
| 1730 | obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE; |
| 1731 | |
| 1732 | if (obuf->len > len) |
| 1733 | obuf->len = len; |
| 1734 | ret += obuf->len; |
| 1735 | len -= obuf->len; |
| 1736 | |
| 1737 | o_head++; |
| 1738 | opipe->head = o_head; |
| 1739 | i_tail++; |
| 1740 | } while (len); |
| 1741 | |
| 1742 | pipe_unlock(ipipe); |
| 1743 | pipe_unlock(opipe); |
| 1744 | |
| 1745 | /* |
| 1746 | * If we put data in the output pipe, wakeup any potential readers. |
| 1747 | */ |
| 1748 | if (ret > 0) |
| 1749 | wakeup_pipe_readers(opipe); |
| 1750 | |
| 1751 | return ret; |
| 1752 | } |
| 1753 | |
| 1754 | /* |
| 1755 | * This is a tee(1) implementation that works on pipes. It doesn't copy |
| 1756 | * any data, it simply references the 'in' pages on the 'out' pipe. |
| 1757 | * The 'flags' used are the SPLICE_F_* variants, currently the only |
| 1758 | * applicable one is SPLICE_F_NONBLOCK. |
| 1759 | */ |
| 1760 | long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags) |
| 1761 | { |
| 1762 | struct pipe_inode_info *ipipe = get_pipe_info(in, true); |
| 1763 | struct pipe_inode_info *opipe = get_pipe_info(out, true); |
| 1764 | int ret = -EINVAL; |
| 1765 | |
| 1766 | if (unlikely(!(in->f_mode & FMODE_READ) || |
| 1767 | !(out->f_mode & FMODE_WRITE))) |
| 1768 | return -EBADF; |
| 1769 | |
| 1770 | /* |
| 1771 | * Duplicate the contents of ipipe to opipe without actually |
| 1772 | * copying the data. |
| 1773 | */ |
| 1774 | if (ipipe && opipe && ipipe != opipe) { |
| 1775 | if ((in->f_flags | out->f_flags) & O_NONBLOCK) |
| 1776 | flags |= SPLICE_F_NONBLOCK; |
| 1777 | |
| 1778 | /* |
| 1779 | * Keep going, unless we encounter an error. The ipipe/opipe |
| 1780 | * ordering doesn't really matter. |
| 1781 | */ |
| 1782 | ret = ipipe_prep(ipipe, flags); |
| 1783 | if (!ret) { |
| 1784 | ret = opipe_prep(opipe, flags); |
| 1785 | if (!ret) |
| 1786 | ret = link_pipe(ipipe, opipe, len, flags); |
| 1787 | } |
| 1788 | } |
| 1789 | |
| 1790 | return ret; |
| 1791 | } |
| 1792 | |
| 1793 | SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags) |
| 1794 | { |
| 1795 | struct fd in, out; |
| 1796 | int error; |
| 1797 | |
| 1798 | if (unlikely(flags & ~SPLICE_F_ALL)) |
| 1799 | return -EINVAL; |
| 1800 | |
| 1801 | if (unlikely(!len)) |
| 1802 | return 0; |
| 1803 | |
| 1804 | error = -EBADF; |
| 1805 | in = fdget(fdin); |
| 1806 | if (in.file) { |
| 1807 | out = fdget(fdout); |
| 1808 | if (out.file) { |
| 1809 | error = do_tee(in.file, out.file, len, flags); |
| 1810 | fdput(out); |
| 1811 | } |
| 1812 | fdput(in); |
| 1813 | } |
| 1814 | |
| 1815 | return error; |
| 1816 | } |