1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_mac.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/fcntl.h> 45 #include <sys/file.h> 46 #include <sys/kdb.h> 47 #include <sys/stat.h> 48 #include <sys/priv.h> 49 #include <sys/proc.h> 50 #include <sys/limits.h> 51 #include <sys/lock.h> 52 #include <sys/mount.h> 53 #include <sys/mutex.h> 54 #include <sys/namei.h> 55 #include <sys/vnode.h> 56 #include <sys/bio.h> 57 #include <sys/buf.h> 58 #include <sys/filio.h> 59 #include <sys/sx.h> 60 #include <sys/ttycom.h> 61 #include <sys/conf.h> 62 #include <sys/syslog.h> 63 #include <sys/unistd.h> 64 65 #include <security/mac/mac_framework.h> 66 67 static fo_rdwr_t vn_read; 68 static fo_rdwr_t vn_write; 69 static fo_truncate_t vn_truncate; 70 static fo_ioctl_t vn_ioctl; 71 static fo_poll_t vn_poll; 72 static fo_kqfilter_t vn_kqfilter; 73 static fo_stat_t vn_statfile; 74 static fo_close_t vn_closefile; 75 76 struct fileops vnops = { 77 .fo_read = vn_read, 78 .fo_write = vn_write, 79 .fo_truncate = vn_truncate, 80 .fo_ioctl = vn_ioctl, 81 .fo_poll = vn_poll, 82 .fo_kqfilter = vn_kqfilter, 83 .fo_stat = vn_statfile, 84 .fo_close = vn_closefile, 85 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 86 }; 87 88 int 89 vn_open(ndp, flagp, cmode, fp) 90 struct nameidata *ndp; 91 int *flagp, cmode; 92 struct file *fp; 93 { 94 struct thread *td = ndp->ni_cnd.cn_thread; 95 96 return (vn_open_cred(ndp, flagp, cmode, td->td_ucred, fp)); 97 } 98 99 /* 100 * Common code for vnode open operations. 101 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 102 * 103 * Note that this does NOT free nameidata for the successful case, 104 * due to the NDINIT being done elsewhere. 105 */ 106 int 107 vn_open_cred(ndp, flagp, cmode, cred, fp) 108 struct nameidata *ndp; 109 int *flagp, cmode; 110 struct ucred *cred; 111 struct file *fp; 112 { 113 struct vnode *vp; 114 struct mount *mp; 115 struct thread *td = ndp->ni_cnd.cn_thread; 116 struct vattr vat; 117 struct vattr *vap = &vat; 118 int mode, fmode, error; 119 int vfslocked, mpsafe; 120 121 mpsafe = ndp->ni_cnd.cn_flags & MPSAFE; 122 restart: 123 vfslocked = 0; 124 fmode = *flagp; 125 if (fmode & O_CREAT) { 126 ndp->ni_cnd.cn_nameiop = CREATE; 127 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | 128 MPSAFE | AUDITVNODE1; 129 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 130 ndp->ni_cnd.cn_flags |= FOLLOW; 131 bwillwrite(); 132 if ((error = namei(ndp)) != 0) 133 return (error); 134 vfslocked = NDHASGIANT(ndp); 135 if (!mpsafe) 136 ndp->ni_cnd.cn_flags &= ~MPSAFE; 137 if (ndp->ni_vp == NULL) { 138 VATTR_NULL(vap); 139 vap->va_type = VREG; 140 vap->va_mode = cmode; 141 if (fmode & O_EXCL) 142 vap->va_vaflags |= VA_EXCLUSIVE; 143 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 144 NDFREE(ndp, NDF_ONLY_PNBUF); 145 vput(ndp->ni_dvp); 146 VFS_UNLOCK_GIANT(vfslocked); 147 if ((error = vn_start_write(NULL, &mp, 148 V_XSLEEP | PCATCH)) != 0) 149 return (error); 150 goto restart; 151 } 152 #ifdef MAC 153 error = mac_vnode_check_create(cred, ndp->ni_dvp, 154 &ndp->ni_cnd, vap); 155 if (error == 0) { 156 #endif 157 VOP_LEASE(ndp->ni_dvp, td, cred, LEASE_WRITE); 158 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 159 &ndp->ni_cnd, vap); 160 #ifdef MAC 161 } 162 #endif 163 vput(ndp->ni_dvp); 164 vn_finished_write(mp); 165 if (error) { 166 VFS_UNLOCK_GIANT(vfslocked); 167 NDFREE(ndp, NDF_ONLY_PNBUF); 168 return (error); 169 } 170 fmode &= ~O_TRUNC; 171 vp = ndp->ni_vp; 172 } else { 173 if (ndp->ni_dvp == ndp->ni_vp) 174 vrele(ndp->ni_dvp); 175 else 176 vput(ndp->ni_dvp); 177 ndp->ni_dvp = NULL; 178 vp = ndp->ni_vp; 179 if (fmode & O_EXCL) { 180 error = EEXIST; 181 goto bad; 182 } 183 fmode &= ~O_CREAT; 184 } 185 } else { 186 ndp->ni_cnd.cn_nameiop = LOOKUP; 187 ndp->ni_cnd.cn_flags = ISOPEN | 188 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | 189 LOCKLEAF | MPSAFE | AUDITVNODE1; 190 if ((error = namei(ndp)) != 0) 191 return (error); 192 if (!mpsafe) 193 ndp->ni_cnd.cn_flags &= ~MPSAFE; 194 vfslocked = NDHASGIANT(ndp); 195 vp = ndp->ni_vp; 196 } 197 if (vp->v_type == VLNK) { 198 error = EMLINK; 199 goto bad; 200 } 201 if (vp->v_type == VSOCK) { 202 error = EOPNOTSUPP; 203 goto bad; 204 } 205 mode = 0; 206 if (fmode & (FWRITE | O_TRUNC)) { 207 if (vp->v_type == VDIR) { 208 error = EISDIR; 209 goto bad; 210 } 211 mode |= VWRITE; 212 } 213 if (fmode & FREAD) 214 mode |= VREAD; 215 if (fmode & FEXEC) 216 mode |= VEXEC; 217 if (fmode & O_APPEND) 218 mode |= VAPPEND; 219 #ifdef MAC 220 error = mac_vnode_check_open(cred, vp, mode); 221 if (error) 222 goto bad; 223 #endif 224 if ((fmode & O_CREAT) == 0) { 225 if (mode & VWRITE) { 226 error = vn_writechk(vp); 227 if (error) 228 goto bad; 229 } 230 if (mode) { 231 error = VOP_ACCESS(vp, mode, cred, td); 232 if (error) 233 goto bad; 234 } 235 } 236 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0) 237 goto bad; 238 239 if (fmode & FWRITE) 240 vp->v_writecount++; 241 *flagp = fmode; 242 ASSERT_VOP_ELOCKED(vp, "vn_open_cred"); 243 if (!mpsafe) 244 VFS_UNLOCK_GIANT(vfslocked); 245 return (0); 246 bad: 247 NDFREE(ndp, NDF_ONLY_PNBUF); 248 vput(vp); 249 VFS_UNLOCK_GIANT(vfslocked); 250 *flagp = fmode; 251 ndp->ni_vp = NULL; 252 return (error); 253 } 254 255 /* 256 * Check for write permissions on the specified vnode. 257 * Prototype text segments cannot be written. 258 */ 259 int 260 vn_writechk(vp) 261 register struct vnode *vp; 262 { 263 264 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 265 /* 266 * If there's shared text associated with 267 * the vnode, try to free it up once. If 268 * we fail, we can't allow writing. 269 */ 270 if (vp->v_vflag & VV_TEXT) 271 return (ETXTBSY); 272 273 return (0); 274 } 275 276 /* 277 * Vnode close call 278 */ 279 int 280 vn_close(vp, flags, file_cred, td) 281 register struct vnode *vp; 282 int flags; 283 struct ucred *file_cred; 284 struct thread *td; 285 { 286 struct mount *mp; 287 int error; 288 289 VFS_ASSERT_GIANT(vp->v_mount); 290 291 vn_start_write(vp, &mp, V_WAIT); 292 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 293 if (flags & FWRITE) { 294 VNASSERT(vp->v_writecount > 0, vp, 295 ("vn_close: negative writecount")); 296 vp->v_writecount--; 297 } 298 error = VOP_CLOSE(vp, flags, file_cred, td); 299 vput(vp); 300 vn_finished_write(mp); 301 return (error); 302 } 303 304 /* 305 * Heuristic to detect sequential operation. 306 */ 307 static int 308 sequential_heuristic(struct uio *uio, struct file *fp) 309 { 310 311 /* 312 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 313 * that the first I/O is normally considered to be slightly 314 * sequential. Seeking to offset 0 doesn't change sequentiality 315 * unless previous seeks have reduced f_seqcount to 0, in which 316 * case offset 0 is not special. 317 */ 318 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 319 uio->uio_offset == fp->f_nextoff) { 320 /* 321 * f_seqcount is in units of fixed-size blocks so that it 322 * depends mainly on the amount of sequential I/O and not 323 * much on the number of sequential I/O's. The fixed size 324 * of 16384 is hard-coded here since it is (not quite) just 325 * a magic size that works well here. This size is more 326 * closely related to the best I/O size for real disks than 327 * to any block size used by software. 328 */ 329 fp->f_seqcount += howmany(uio->uio_resid, 16384); 330 if (fp->f_seqcount > IO_SEQMAX) 331 fp->f_seqcount = IO_SEQMAX; 332 return (fp->f_seqcount << IO_SEQSHIFT); 333 } 334 335 /* Not sequential. Quickly draw-down sequentiality. */ 336 if (fp->f_seqcount > 1) 337 fp->f_seqcount = 1; 338 else 339 fp->f_seqcount = 0; 340 return (0); 341 } 342 343 /* 344 * Package up an I/O request on a vnode into a uio and do it. 345 */ 346 int 347 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, active_cred, file_cred, 348 aresid, td) 349 enum uio_rw rw; 350 struct vnode *vp; 351 void *base; 352 int len; 353 off_t offset; 354 enum uio_seg segflg; 355 int ioflg; 356 struct ucred *active_cred; 357 struct ucred *file_cred; 358 int *aresid; 359 struct thread *td; 360 { 361 struct uio auio; 362 struct iovec aiov; 363 struct mount *mp; 364 struct ucred *cred; 365 int error; 366 367 VFS_ASSERT_GIANT(vp->v_mount); 368 369 if ((ioflg & IO_NODELOCKED) == 0) { 370 mp = NULL; 371 if (rw == UIO_WRITE) { 372 if (vp->v_type != VCHR && 373 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 374 != 0) 375 return (error); 376 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 377 } else { 378 /* 379 * XXX This should be LK_SHARED but I don't trust VFS 380 * enough to leave it like that until it has been 381 * reviewed further. 382 */ 383 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 384 } 385 386 } 387 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 388 auio.uio_iov = &aiov; 389 auio.uio_iovcnt = 1; 390 aiov.iov_base = base; 391 aiov.iov_len = len; 392 auio.uio_resid = len; 393 auio.uio_offset = offset; 394 auio.uio_segflg = segflg; 395 auio.uio_rw = rw; 396 auio.uio_td = td; 397 error = 0; 398 #ifdef MAC 399 if ((ioflg & IO_NOMACCHECK) == 0) { 400 if (rw == UIO_READ) 401 error = mac_vnode_check_read(active_cred, file_cred, 402 vp); 403 else 404 error = mac_vnode_check_write(active_cred, file_cred, 405 vp); 406 } 407 #endif 408 if (error == 0) { 409 if (file_cred) 410 cred = file_cred; 411 else 412 cred = active_cred; 413 if (rw == UIO_READ) 414 error = VOP_READ(vp, &auio, ioflg, cred); 415 else 416 error = VOP_WRITE(vp, &auio, ioflg, cred); 417 } 418 if (aresid) 419 *aresid = auio.uio_resid; 420 else 421 if (auio.uio_resid && error == 0) 422 error = EIO; 423 if ((ioflg & IO_NODELOCKED) == 0) { 424 if (rw == UIO_WRITE && vp->v_type != VCHR) 425 vn_finished_write(mp); 426 VOP_UNLOCK(vp, 0); 427 } 428 return (error); 429 } 430 431 /* 432 * Package up an I/O request on a vnode into a uio and do it. The I/O 433 * request is split up into smaller chunks and we try to avoid saturating 434 * the buffer cache while potentially holding a vnode locked, so we 435 * check bwillwrite() before calling vn_rdwr(). We also call uio_yield() 436 * to give other processes a chance to lock the vnode (either other processes 437 * core'ing the same binary, or unrelated processes scanning the directory). 438 */ 439 int 440 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred, 441 file_cred, aresid, td) 442 enum uio_rw rw; 443 struct vnode *vp; 444 void *base; 445 size_t len; 446 off_t offset; 447 enum uio_seg segflg; 448 int ioflg; 449 struct ucred *active_cred; 450 struct ucred *file_cred; 451 size_t *aresid; 452 struct thread *td; 453 { 454 int error = 0; 455 int iaresid; 456 457 VFS_ASSERT_GIANT(vp->v_mount); 458 459 do { 460 int chunk; 461 462 /* 463 * Force `offset' to a multiple of MAXBSIZE except possibly 464 * for the first chunk, so that filesystems only need to 465 * write full blocks except possibly for the first and last 466 * chunks. 467 */ 468 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 469 470 if (chunk > len) 471 chunk = len; 472 if (rw != UIO_READ && vp->v_type == VREG) 473 bwillwrite(); 474 iaresid = 0; 475 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 476 ioflg, active_cred, file_cred, &iaresid, td); 477 len -= chunk; /* aresid calc already includes length */ 478 if (error) 479 break; 480 offset += chunk; 481 base = (char *)base + chunk; 482 uio_yield(); 483 } while (len); 484 if (aresid) 485 *aresid = len + iaresid; 486 return (error); 487 } 488 489 /* 490 * File table vnode read routine. 491 */ 492 static int 493 vn_read(fp, uio, active_cred, flags, td) 494 struct file *fp; 495 struct uio *uio; 496 struct ucred *active_cred; 497 struct thread *td; 498 int flags; 499 { 500 struct vnode *vp; 501 int error, ioflag; 502 struct mtx *mtxp; 503 int vfslocked; 504 505 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 506 uio->uio_td, td)); 507 mtxp = NULL; 508 vp = fp->f_vnode; 509 ioflag = 0; 510 if (fp->f_flag & FNONBLOCK) 511 ioflag |= IO_NDELAY; 512 if (fp->f_flag & O_DIRECT) 513 ioflag |= IO_DIRECT; 514 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 515 VOP_LEASE(vp, td, fp->f_cred, LEASE_READ); 516 /* 517 * According to McKusick the vn lock was protecting f_offset here. 518 * It is now protected by the FOFFSET_LOCKED flag. 519 */ 520 if ((flags & FOF_OFFSET) == 0) { 521 mtxp = mtx_pool_find(mtxpool_sleep, fp); 522 mtx_lock(mtxp); 523 while(fp->f_vnread_flags & FOFFSET_LOCKED) { 524 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 525 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 526 "vnread offlock", 0); 527 } 528 fp->f_vnread_flags |= FOFFSET_LOCKED; 529 mtx_unlock(mtxp); 530 vn_lock(vp, LK_SHARED | LK_RETRY); 531 uio->uio_offset = fp->f_offset; 532 } else 533 vn_lock(vp, LK_SHARED | LK_RETRY); 534 535 ioflag |= sequential_heuristic(uio, fp); 536 537 #ifdef MAC 538 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 539 if (error == 0) 540 #endif 541 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 542 if ((flags & FOF_OFFSET) == 0) { 543 fp->f_offset = uio->uio_offset; 544 mtx_lock(mtxp); 545 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 546 wakeup(&fp->f_vnread_flags); 547 fp->f_vnread_flags = 0; 548 mtx_unlock(mtxp); 549 } 550 fp->f_nextoff = uio->uio_offset; 551 VOP_UNLOCK(vp, 0); 552 VFS_UNLOCK_GIANT(vfslocked); 553 return (error); 554 } 555 556 /* 557 * File table vnode write routine. 558 */ 559 static int 560 vn_write(fp, uio, active_cred, flags, td) 561 struct file *fp; 562 struct uio *uio; 563 struct ucred *active_cred; 564 struct thread *td; 565 int flags; 566 { 567 struct vnode *vp; 568 struct mount *mp; 569 int error, ioflag; 570 int vfslocked; 571 572 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 573 uio->uio_td, td)); 574 vp = fp->f_vnode; 575 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 576 if (vp->v_type == VREG) 577 bwillwrite(); 578 ioflag = IO_UNIT; 579 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 580 ioflag |= IO_APPEND; 581 if (fp->f_flag & FNONBLOCK) 582 ioflag |= IO_NDELAY; 583 if (fp->f_flag & O_DIRECT) 584 ioflag |= IO_DIRECT; 585 if ((fp->f_flag & O_FSYNC) || 586 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 587 ioflag |= IO_SYNC; 588 mp = NULL; 589 if (vp->v_type != VCHR && 590 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 591 goto unlock; 592 VOP_LEASE(vp, td, fp->f_cred, LEASE_WRITE); 593 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 594 if ((flags & FOF_OFFSET) == 0) 595 uio->uio_offset = fp->f_offset; 596 ioflag |= sequential_heuristic(uio, fp); 597 #ifdef MAC 598 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 599 if (error == 0) 600 #endif 601 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 602 if ((flags & FOF_OFFSET) == 0) 603 fp->f_offset = uio->uio_offset; 604 fp->f_nextoff = uio->uio_offset; 605 VOP_UNLOCK(vp, 0); 606 if (vp->v_type != VCHR) 607 vn_finished_write(mp); 608 unlock: 609 VFS_UNLOCK_GIANT(vfslocked); 610 return (error); 611 } 612 613 /* 614 * File table truncate routine. 615 */ 616 static int 617 vn_truncate(fp, length, active_cred, td) 618 struct file *fp; 619 off_t length; 620 struct ucred *active_cred; 621 struct thread *td; 622 { 623 struct vattr vattr; 624 struct mount *mp; 625 struct vnode *vp; 626 int vfslocked; 627 int error; 628 629 vp = fp->f_vnode; 630 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 631 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 632 if (error) { 633 VFS_UNLOCK_GIANT(vfslocked); 634 return (error); 635 } 636 VOP_LEASE(vp, td, active_cred, LEASE_WRITE); 637 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 638 if (vp->v_type == VDIR) { 639 error = EISDIR; 640 goto out; 641 } 642 #ifdef MAC 643 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 644 if (error) 645 goto out; 646 #endif 647 error = vn_writechk(vp); 648 if (error == 0) { 649 VATTR_NULL(&vattr); 650 vattr.va_size = length; 651 error = VOP_SETATTR(vp, &vattr, fp->f_cred); 652 } 653 out: 654 VOP_UNLOCK(vp, 0); 655 vn_finished_write(mp); 656 VFS_UNLOCK_GIANT(vfslocked); 657 return (error); 658 } 659 660 /* 661 * File table vnode stat routine. 662 */ 663 static int 664 vn_statfile(fp, sb, active_cred, td) 665 struct file *fp; 666 struct stat *sb; 667 struct ucred *active_cred; 668 struct thread *td; 669 { 670 struct vnode *vp = fp->f_vnode; 671 int vfslocked; 672 int error; 673 674 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 675 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 676 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 677 VOP_UNLOCK(vp, 0); 678 VFS_UNLOCK_GIANT(vfslocked); 679 680 return (error); 681 } 682 683 /* 684 * Stat a vnode; implementation for the stat syscall 685 */ 686 int 687 vn_stat(vp, sb, active_cred, file_cred, td) 688 struct vnode *vp; 689 register struct stat *sb; 690 struct ucred *active_cred; 691 struct ucred *file_cred; 692 struct thread *td; 693 { 694 struct vattr vattr; 695 register struct vattr *vap; 696 int error; 697 u_short mode; 698 699 #ifdef MAC 700 error = mac_vnode_check_stat(active_cred, file_cred, vp); 701 if (error) 702 return (error); 703 #endif 704 705 vap = &vattr; 706 707 /* 708 * Initialize defaults for new and unusual fields, so that file 709 * systems which don't support these fields don't need to know 710 * about them. 711 */ 712 vap->va_birthtime.tv_sec = -1; 713 vap->va_birthtime.tv_nsec = 0; 714 vap->va_fsid = VNOVAL; 715 vap->va_rdev = NODEV; 716 717 error = VOP_GETATTR(vp, vap, active_cred); 718 if (error) 719 return (error); 720 721 /* 722 * Zero the spare stat fields 723 */ 724 bzero(sb, sizeof *sb); 725 726 /* 727 * Copy from vattr table 728 */ 729 if (vap->va_fsid != VNOVAL) 730 sb->st_dev = vap->va_fsid; 731 else 732 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 733 sb->st_ino = vap->va_fileid; 734 mode = vap->va_mode; 735 switch (vap->va_type) { 736 case VREG: 737 mode |= S_IFREG; 738 break; 739 case VDIR: 740 mode |= S_IFDIR; 741 break; 742 case VBLK: 743 mode |= S_IFBLK; 744 break; 745 case VCHR: 746 mode |= S_IFCHR; 747 break; 748 case VLNK: 749 mode |= S_IFLNK; 750 break; 751 case VSOCK: 752 mode |= S_IFSOCK; 753 break; 754 case VFIFO: 755 mode |= S_IFIFO; 756 break; 757 default: 758 return (EBADF); 759 }; 760 sb->st_mode = mode; 761 sb->st_nlink = vap->va_nlink; 762 sb->st_uid = vap->va_uid; 763 sb->st_gid = vap->va_gid; 764 sb->st_rdev = vap->va_rdev; 765 if (vap->va_size > OFF_MAX) 766 return (EOVERFLOW); 767 sb->st_size = vap->va_size; 768 sb->st_atimespec = vap->va_atime; 769 sb->st_mtimespec = vap->va_mtime; 770 sb->st_ctimespec = vap->va_ctime; 771 sb->st_birthtimespec = vap->va_birthtime; 772 773 /* 774 * According to www.opengroup.org, the meaning of st_blksize is 775 * "a filesystem-specific preferred I/O block size for this 776 * object. In some filesystem types, this may vary from file 777 * to file" 778 * Default to PAGE_SIZE after much discussion. 779 * XXX: min(PAGE_SIZE, vp->v_bufobj.bo_bsize) may be more correct. 780 */ 781 782 sb->st_blksize = PAGE_SIZE; 783 784 sb->st_flags = vap->va_flags; 785 if (priv_check(td, PRIV_VFS_GENERATION)) 786 sb->st_gen = 0; 787 else 788 sb->st_gen = vap->va_gen; 789 790 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 791 return (0); 792 } 793 794 /* 795 * File table vnode ioctl routine. 796 */ 797 static int 798 vn_ioctl(fp, com, data, active_cred, td) 799 struct file *fp; 800 u_long com; 801 void *data; 802 struct ucred *active_cred; 803 struct thread *td; 804 { 805 struct vnode *vp = fp->f_vnode; 806 struct vattr vattr; 807 int vfslocked; 808 int error; 809 810 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 811 error = ENOTTY; 812 switch (vp->v_type) { 813 case VREG: 814 case VDIR: 815 if (com == FIONREAD) { 816 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 817 error = VOP_GETATTR(vp, &vattr, active_cred); 818 VOP_UNLOCK(vp, 0); 819 if (!error) 820 *(int *)data = vattr.va_size - fp->f_offset; 821 } 822 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 823 error = 0; 824 else 825 error = VOP_IOCTL(vp, com, data, fp->f_flag, 826 active_cred, td); 827 break; 828 829 default: 830 break; 831 } 832 VFS_UNLOCK_GIANT(vfslocked); 833 return (error); 834 } 835 836 /* 837 * File table vnode poll routine. 838 */ 839 static int 840 vn_poll(fp, events, active_cred, td) 841 struct file *fp; 842 int events; 843 struct ucred *active_cred; 844 struct thread *td; 845 { 846 struct vnode *vp; 847 int vfslocked; 848 int error; 849 850 vp = fp->f_vnode; 851 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 852 #ifdef MAC 853 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 854 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 855 VOP_UNLOCK(vp, 0); 856 if (!error) 857 #endif 858 859 error = VOP_POLL(vp, events, fp->f_cred, td); 860 VFS_UNLOCK_GIANT(vfslocked); 861 return (error); 862 } 863 864 /* 865 * Acquire the requested lock and then check for validity. LK_RETRY 866 * permits vn_lock to return doomed vnodes. 867 */ 868 int 869 _vn_lock(struct vnode *vp, int flags, char *file, int line) 870 { 871 int error; 872 873 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 874 ("vn_lock called with no locktype.")); 875 do { 876 error = VOP_LOCK1(vp, flags, file, line); 877 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ 878 KASSERT((flags & LK_RETRY) == 0 || error == 0, 879 ("LK_RETRY set with incompatible flags %d\n", flags)); 880 /* 881 * Callers specify LK_RETRY if they wish to get dead vnodes. 882 * If RETRY is not set, we return ENOENT instead. 883 */ 884 if (error == 0 && vp->v_iflag & VI_DOOMED && 885 (flags & LK_RETRY) == 0) { 886 VOP_UNLOCK(vp, 0); 887 error = ENOENT; 888 break; 889 } 890 } while (flags & LK_RETRY && error != 0); 891 return (error); 892 } 893 894 /* 895 * File table vnode close routine. 896 */ 897 static int 898 vn_closefile(fp, td) 899 struct file *fp; 900 struct thread *td; 901 { 902 struct vnode *vp; 903 struct flock lf; 904 int vfslocked; 905 int error; 906 907 vp = fp->f_vnode; 908 909 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 910 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) { 911 lf.l_whence = SEEK_SET; 912 lf.l_start = 0; 913 lf.l_len = 0; 914 lf.l_type = F_UNLCK; 915 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 916 } 917 918 fp->f_ops = &badfileops; 919 920 error = vn_close(vp, fp->f_flag, fp->f_cred, td); 921 VFS_UNLOCK_GIANT(vfslocked); 922 return (error); 923 } 924 925 /* 926 * Preparing to start a filesystem write operation. If the operation is 927 * permitted, then we bump the count of operations in progress and 928 * proceed. If a suspend request is in progress, we wait until the 929 * suspension is over, and then proceed. 930 */ 931 int 932 vn_start_write(vp, mpp, flags) 933 struct vnode *vp; 934 struct mount **mpp; 935 int flags; 936 { 937 struct mount *mp; 938 int error; 939 940 error = 0; 941 /* 942 * If a vnode is provided, get and return the mount point that 943 * to which it will write. 944 */ 945 if (vp != NULL) { 946 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 947 *mpp = NULL; 948 if (error != EOPNOTSUPP) 949 return (error); 950 return (0); 951 } 952 } 953 if ((mp = *mpp) == NULL) 954 return (0); 955 MNT_ILOCK(mp); 956 if (vp == NULL) 957 MNT_REF(mp); 958 /* 959 * Check on status of suspension. 960 */ 961 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 962 mp->mnt_susp_owner != curthread) { 963 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 964 if (flags & V_NOWAIT) { 965 error = EWOULDBLOCK; 966 goto unlock; 967 } 968 error = msleep(&mp->mnt_flag, MNT_MTX(mp), 969 (PUSER - 1) | (flags & PCATCH), "suspfs", 0); 970 if (error) 971 goto unlock; 972 } 973 } 974 if (flags & V_XSLEEP) 975 goto unlock; 976 mp->mnt_writeopcount++; 977 unlock: 978 MNT_REL(mp); 979 MNT_IUNLOCK(mp); 980 return (error); 981 } 982 983 /* 984 * Secondary suspension. Used by operations such as vop_inactive 985 * routines that are needed by the higher level functions. These 986 * are allowed to proceed until all the higher level functions have 987 * completed (indicated by mnt_writeopcount dropping to zero). At that 988 * time, these operations are halted until the suspension is over. 989 */ 990 int 991 vn_start_secondary_write(vp, mpp, flags) 992 struct vnode *vp; 993 struct mount **mpp; 994 int flags; 995 { 996 struct mount *mp; 997 int error; 998 999 retry: 1000 if (vp != NULL) { 1001 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1002 *mpp = NULL; 1003 if (error != EOPNOTSUPP) 1004 return (error); 1005 return (0); 1006 } 1007 } 1008 /* 1009 * If we are not suspended or have not yet reached suspended 1010 * mode, then let the operation proceed. 1011 */ 1012 if ((mp = *mpp) == NULL) 1013 return (0); 1014 MNT_ILOCK(mp); 1015 if (vp == NULL) 1016 MNT_REF(mp); 1017 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1018 mp->mnt_secondary_writes++; 1019 mp->mnt_secondary_accwrites++; 1020 MNT_REL(mp); 1021 MNT_IUNLOCK(mp); 1022 return (0); 1023 } 1024 if (flags & V_NOWAIT) { 1025 MNT_REL(mp); 1026 MNT_IUNLOCK(mp); 1027 return (EWOULDBLOCK); 1028 } 1029 /* 1030 * Wait for the suspension to finish. 1031 */ 1032 error = msleep(&mp->mnt_flag, MNT_MTX(mp), 1033 (PUSER - 1) | (flags & PCATCH) | PDROP, "suspfs", 0); 1034 vfs_rel(mp); 1035 if (error == 0) 1036 goto retry; 1037 return (error); 1038 } 1039 1040 /* 1041 * Filesystem write operation has completed. If we are suspending and this 1042 * operation is the last one, notify the suspender that the suspension is 1043 * now in effect. 1044 */ 1045 void 1046 vn_finished_write(mp) 1047 struct mount *mp; 1048 { 1049 if (mp == NULL) 1050 return; 1051 MNT_ILOCK(mp); 1052 mp->mnt_writeopcount--; 1053 if (mp->mnt_writeopcount < 0) 1054 panic("vn_finished_write: neg cnt"); 1055 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1056 mp->mnt_writeopcount <= 0) 1057 wakeup(&mp->mnt_writeopcount); 1058 MNT_IUNLOCK(mp); 1059 } 1060 1061 1062 /* 1063 * Filesystem secondary write operation has completed. If we are 1064 * suspending and this operation is the last one, notify the suspender 1065 * that the suspension is now in effect. 1066 */ 1067 void 1068 vn_finished_secondary_write(mp) 1069 struct mount *mp; 1070 { 1071 if (mp == NULL) 1072 return; 1073 MNT_ILOCK(mp); 1074 mp->mnt_secondary_writes--; 1075 if (mp->mnt_secondary_writes < 0) 1076 panic("vn_finished_secondary_write: neg cnt"); 1077 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1078 mp->mnt_secondary_writes <= 0) 1079 wakeup(&mp->mnt_secondary_writes); 1080 MNT_IUNLOCK(mp); 1081 } 1082 1083 1084 1085 /* 1086 * Request a filesystem to suspend write operations. 1087 */ 1088 int 1089 vfs_write_suspend(mp) 1090 struct mount *mp; 1091 { 1092 struct thread *td = curthread; 1093 int error; 1094 1095 MNT_ILOCK(mp); 1096 if (mp->mnt_susp_owner == curthread) { 1097 MNT_IUNLOCK(mp); 1098 return (EALREADY); 1099 } 1100 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1101 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1102 mp->mnt_kern_flag |= MNTK_SUSPEND; 1103 mp->mnt_susp_owner = curthread; 1104 if (mp->mnt_writeopcount > 0) 1105 (void) msleep(&mp->mnt_writeopcount, 1106 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1107 else 1108 MNT_IUNLOCK(mp); 1109 if ((error = VFS_SYNC(mp, MNT_SUSPEND, td)) != 0) 1110 vfs_write_resume(mp); 1111 return (error); 1112 } 1113 1114 /* 1115 * Request a filesystem to resume write operations. 1116 */ 1117 void 1118 vfs_write_resume(mp) 1119 struct mount *mp; 1120 { 1121 1122 MNT_ILOCK(mp); 1123 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1124 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1125 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1126 MNTK_SUSPENDED); 1127 mp->mnt_susp_owner = NULL; 1128 wakeup(&mp->mnt_writeopcount); 1129 wakeup(&mp->mnt_flag); 1130 curthread->td_pflags &= ~TDP_IGNSUSP; 1131 MNT_IUNLOCK(mp); 1132 VFS_SUSP_CLEAN(mp); 1133 } else 1134 MNT_IUNLOCK(mp); 1135 } 1136 1137 /* 1138 * Implement kqueues for files by translating it to vnode operation. 1139 */ 1140 static int 1141 vn_kqfilter(struct file *fp, struct knote *kn) 1142 { 1143 int vfslocked; 1144 int error; 1145 1146 vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount); 1147 error = VOP_KQFILTER(fp->f_vnode, kn); 1148 VFS_UNLOCK_GIANT(vfslocked); 1149 1150 return error; 1151 } 1152 1153 /* 1154 * Simplified in-kernel wrapper calls for extended attribute access. 1155 * Both calls pass in a NULL credential, authorizing as "kernel" access. 1156 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 1157 */ 1158 int 1159 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 1160 const char *attrname, int *buflen, char *buf, struct thread *td) 1161 { 1162 struct uio auio; 1163 struct iovec iov; 1164 int error; 1165 1166 iov.iov_len = *buflen; 1167 iov.iov_base = buf; 1168 1169 auio.uio_iov = &iov; 1170 auio.uio_iovcnt = 1; 1171 auio.uio_rw = UIO_READ; 1172 auio.uio_segflg = UIO_SYSSPACE; 1173 auio.uio_td = td; 1174 auio.uio_offset = 0; 1175 auio.uio_resid = *buflen; 1176 1177 if ((ioflg & IO_NODELOCKED) == 0) 1178 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1179 1180 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1181 1182 /* authorize attribute retrieval as kernel */ 1183 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 1184 td); 1185 1186 if ((ioflg & IO_NODELOCKED) == 0) 1187 VOP_UNLOCK(vp, 0); 1188 1189 if (error == 0) { 1190 *buflen = *buflen - auio.uio_resid; 1191 } 1192 1193 return (error); 1194 } 1195 1196 /* 1197 * XXX failure mode if partially written? 1198 */ 1199 int 1200 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 1201 const char *attrname, int buflen, char *buf, struct thread *td) 1202 { 1203 struct uio auio; 1204 struct iovec iov; 1205 struct mount *mp; 1206 int error; 1207 1208 iov.iov_len = buflen; 1209 iov.iov_base = buf; 1210 1211 auio.uio_iov = &iov; 1212 auio.uio_iovcnt = 1; 1213 auio.uio_rw = UIO_WRITE; 1214 auio.uio_segflg = UIO_SYSSPACE; 1215 auio.uio_td = td; 1216 auio.uio_offset = 0; 1217 auio.uio_resid = buflen; 1218 1219 if ((ioflg & IO_NODELOCKED) == 0) { 1220 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 1221 return (error); 1222 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1223 } 1224 1225 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1226 1227 /* authorize attribute setting as kernel */ 1228 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 1229 1230 if ((ioflg & IO_NODELOCKED) == 0) { 1231 vn_finished_write(mp); 1232 VOP_UNLOCK(vp, 0); 1233 } 1234 1235 return (error); 1236 } 1237 1238 int 1239 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 1240 const char *attrname, struct thread *td) 1241 { 1242 struct mount *mp; 1243 int error; 1244 1245 if ((ioflg & IO_NODELOCKED) == 0) { 1246 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 1247 return (error); 1248 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1249 } 1250 1251 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1252 1253 /* authorize attribute removal as kernel */ 1254 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 1255 if (error == EOPNOTSUPP) 1256 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 1257 NULL, td); 1258 1259 if ((ioflg & IO_NODELOCKED) == 0) { 1260 vn_finished_write(mp); 1261 VOP_UNLOCK(vp, 0); 1262 } 1263 1264 return (error); 1265 } 1266