vfs_vnops.c revision 331722
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 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 11 * Copyright (c) 2013, 2014 The FreeBSD Foundation 12 * 13 * Portions of this software were developed by Konstantin Belousov 14 * under sponsorship from the FreeBSD Foundation. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 41 */ 42 43#include <sys/cdefs.h> 44__FBSDID("$FreeBSD: stable/11/sys/kern/vfs_vnops.c 331722 2018-03-29 02:50:57Z eadler $"); 45 46#include "opt_hwpmc_hooks.h" 47 48#include <sys/param.h> 49#include <sys/systm.h> 50#include <sys/disk.h> 51#include <sys/fail.h> 52#include <sys/fcntl.h> 53#include <sys/file.h> 54#include <sys/kdb.h> 55#include <sys/stat.h> 56#include <sys/priv.h> 57#include <sys/proc.h> 58#include <sys/limits.h> 59#include <sys/lock.h> 60#include <sys/mman.h> 61#include <sys/mount.h> 62#include <sys/mutex.h> 63#include <sys/namei.h> 64#include <sys/vnode.h> 65#include <sys/bio.h> 66#include <sys/buf.h> 67#include <sys/filio.h> 68#include <sys/resourcevar.h> 69#include <sys/rwlock.h> 70#include <sys/sx.h> 71#include <sys/sysctl.h> 72#include <sys/ttycom.h> 73#include <sys/conf.h> 74#include <sys/syslog.h> 75#include <sys/unistd.h> 76#include <sys/user.h> 77 78#include <security/audit/audit.h> 79#include <security/mac/mac_framework.h> 80 81#include <vm/vm.h> 82#include <vm/vm_extern.h> 83#include <vm/pmap.h> 84#include <vm/vm_map.h> 85#include <vm/vm_object.h> 86#include <vm/vm_page.h> 87#include <vm/vnode_pager.h> 88 89#ifdef HWPMC_HOOKS 90#include <sys/pmckern.h> 91#endif 92 93static fo_rdwr_t vn_read; 94static fo_rdwr_t vn_write; 95static fo_rdwr_t vn_io_fault; 96static fo_truncate_t vn_truncate; 97static fo_ioctl_t vn_ioctl; 98static fo_poll_t vn_poll; 99static fo_kqfilter_t vn_kqfilter; 100static fo_stat_t vn_statfile; 101static fo_close_t vn_closefile; 102static fo_mmap_t vn_mmap; 103 104struct fileops vnops = { 105 .fo_read = vn_io_fault, 106 .fo_write = vn_io_fault, 107 .fo_truncate = vn_truncate, 108 .fo_ioctl = vn_ioctl, 109 .fo_poll = vn_poll, 110 .fo_kqfilter = vn_kqfilter, 111 .fo_stat = vn_statfile, 112 .fo_close = vn_closefile, 113 .fo_chmod = vn_chmod, 114 .fo_chown = vn_chown, 115 .fo_sendfile = vn_sendfile, 116 .fo_seek = vn_seek, 117 .fo_fill_kinfo = vn_fill_kinfo, 118 .fo_mmap = vn_mmap, 119 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 120}; 121 122static const int io_hold_cnt = 16; 123static int vn_io_fault_enable = 1; 124SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW, 125 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 126static int vn_io_fault_prefault = 0; 127SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW, 128 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 129static u_long vn_io_faults_cnt; 130SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 131 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 132 133/* 134 * Returns true if vn_io_fault mode of handling the i/o request should 135 * be used. 136 */ 137static bool 138do_vn_io_fault(struct vnode *vp, struct uio *uio) 139{ 140 struct mount *mp; 141 142 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 143 (mp = vp->v_mount) != NULL && 144 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 145} 146 147/* 148 * Structure used to pass arguments to vn_io_fault1(), to do either 149 * file- or vnode-based I/O calls. 150 */ 151struct vn_io_fault_args { 152 enum { 153 VN_IO_FAULT_FOP, 154 VN_IO_FAULT_VOP 155 } kind; 156 struct ucred *cred; 157 int flags; 158 union { 159 struct fop_args_tag { 160 struct file *fp; 161 fo_rdwr_t *doio; 162 } fop_args; 163 struct vop_args_tag { 164 struct vnode *vp; 165 } vop_args; 166 } args; 167}; 168 169static int vn_io_fault1(struct vnode *vp, struct uio *uio, 170 struct vn_io_fault_args *args, struct thread *td); 171 172int 173vn_open(ndp, flagp, cmode, fp) 174 struct nameidata *ndp; 175 int *flagp, cmode; 176 struct file *fp; 177{ 178 struct thread *td = ndp->ni_cnd.cn_thread; 179 180 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 181} 182 183/* 184 * Common code for vnode open operations via a name lookup. 185 * Lookup the vnode and invoke VOP_CREATE if needed. 186 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 187 * 188 * Note that this does NOT free nameidata for the successful case, 189 * due to the NDINIT being done elsewhere. 190 */ 191int 192vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 193 struct ucred *cred, struct file *fp) 194{ 195 struct vnode *vp; 196 struct mount *mp; 197 struct thread *td = ndp->ni_cnd.cn_thread; 198 struct vattr vat; 199 struct vattr *vap = &vat; 200 int fmode, error; 201 202restart: 203 fmode = *flagp; 204 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 205 O_EXCL | O_DIRECTORY)) 206 return (EINVAL); 207 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 208 ndp->ni_cnd.cn_nameiop = CREATE; 209 /* 210 * Set NOCACHE to avoid flushing the cache when 211 * rolling in many files at once. 212 */ 213 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE; 214 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 215 ndp->ni_cnd.cn_flags |= FOLLOW; 216 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 217 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 218 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 219 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 220 bwillwrite(); 221 if ((error = namei(ndp)) != 0) 222 return (error); 223 if (ndp->ni_vp == NULL) { 224 VATTR_NULL(vap); 225 vap->va_type = VREG; 226 vap->va_mode = cmode; 227 if (fmode & O_EXCL) 228 vap->va_vaflags |= VA_EXCLUSIVE; 229 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 230 NDFREE(ndp, NDF_ONLY_PNBUF); 231 vput(ndp->ni_dvp); 232 if ((error = vn_start_write(NULL, &mp, 233 V_XSLEEP | PCATCH)) != 0) 234 return (error); 235 goto restart; 236 } 237 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 238 ndp->ni_cnd.cn_flags |= MAKEENTRY; 239#ifdef MAC 240 error = mac_vnode_check_create(cred, ndp->ni_dvp, 241 &ndp->ni_cnd, vap); 242 if (error == 0) 243#endif 244 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 245 &ndp->ni_cnd, vap); 246 vput(ndp->ni_dvp); 247 vn_finished_write(mp); 248 if (error) { 249 NDFREE(ndp, NDF_ONLY_PNBUF); 250 return (error); 251 } 252 fmode &= ~O_TRUNC; 253 vp = ndp->ni_vp; 254 } else { 255 if (ndp->ni_dvp == ndp->ni_vp) 256 vrele(ndp->ni_dvp); 257 else 258 vput(ndp->ni_dvp); 259 ndp->ni_dvp = NULL; 260 vp = ndp->ni_vp; 261 if (fmode & O_EXCL) { 262 error = EEXIST; 263 goto bad; 264 } 265 fmode &= ~O_CREAT; 266 } 267 } else { 268 ndp->ni_cnd.cn_nameiop = LOOKUP; 269 ndp->ni_cnd.cn_flags = ISOPEN | 270 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 271 if (!(fmode & FWRITE)) 272 ndp->ni_cnd.cn_flags |= LOCKSHARED; 273 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 274 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 275 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 276 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 277 if ((error = namei(ndp)) != 0) 278 return (error); 279 vp = ndp->ni_vp; 280 } 281 error = vn_open_vnode(vp, fmode, cred, td, fp); 282 if (error) 283 goto bad; 284 *flagp = fmode; 285 return (0); 286bad: 287 NDFREE(ndp, NDF_ONLY_PNBUF); 288 vput(vp); 289 *flagp = fmode; 290 ndp->ni_vp = NULL; 291 return (error); 292} 293 294/* 295 * Common code for vnode open operations once a vnode is located. 296 * Check permissions, and call the VOP_OPEN routine. 297 */ 298int 299vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 300 struct thread *td, struct file *fp) 301{ 302 accmode_t accmode; 303 struct flock lf; 304 int error, lock_flags, type; 305 306 if (vp->v_type == VLNK) 307 return (EMLINK); 308 if (vp->v_type == VSOCK) 309 return (EOPNOTSUPP); 310 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 311 return (ENOTDIR); 312 accmode = 0; 313 if (fmode & (FWRITE | O_TRUNC)) { 314 if (vp->v_type == VDIR) 315 return (EISDIR); 316 accmode |= VWRITE; 317 } 318 if (fmode & FREAD) 319 accmode |= VREAD; 320 if (fmode & FEXEC) 321 accmode |= VEXEC; 322 if ((fmode & O_APPEND) && (fmode & FWRITE)) 323 accmode |= VAPPEND; 324#ifdef MAC 325 if (fmode & O_CREAT) 326 accmode |= VCREAT; 327 if (fmode & O_VERIFY) 328 accmode |= VVERIFY; 329 error = mac_vnode_check_open(cred, vp, accmode); 330 if (error) 331 return (error); 332 333 accmode &= ~(VCREAT | VVERIFY); 334#endif 335 if ((fmode & O_CREAT) == 0) { 336 if (accmode & VWRITE) { 337 error = vn_writechk(vp); 338 if (error) 339 return (error); 340 } 341 if (accmode) { 342 error = VOP_ACCESS(vp, accmode, cred, td); 343 if (error) 344 return (error); 345 } 346 } 347 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 348 vn_lock(vp, LK_UPGRADE | LK_RETRY); 349 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0) 350 return (error); 351 352 while ((fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 353 KASSERT(fp != NULL, ("open with flock requires fp")); 354 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) { 355 error = EOPNOTSUPP; 356 break; 357 } 358 lock_flags = VOP_ISLOCKED(vp); 359 VOP_UNLOCK(vp, 0); 360 lf.l_whence = SEEK_SET; 361 lf.l_start = 0; 362 lf.l_len = 0; 363 if (fmode & O_EXLOCK) 364 lf.l_type = F_WRLCK; 365 else 366 lf.l_type = F_RDLCK; 367 type = F_FLOCK; 368 if ((fmode & FNONBLOCK) == 0) 369 type |= F_WAIT; 370 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 371 if (error == 0) 372 fp->f_flag |= FHASLOCK; 373 vn_lock(vp, lock_flags | LK_RETRY); 374 if (error != 0) 375 break; 376 if ((vp->v_iflag & VI_DOOMED) != 0) { 377 error = ENOENT; 378 break; 379 } 380 381 /* 382 * Another thread might have used this vnode as an 383 * executable while the vnode lock was dropped. 384 * Ensure the vnode is still able to be opened for 385 * writing after the lock has been obtained. 386 */ 387 if ((accmode & VWRITE) != 0) 388 error = vn_writechk(vp); 389 break; 390 } 391 392 if (error != 0) { 393 fp->f_flag |= FOPENFAILED; 394 fp->f_vnode = vp; 395 if (fp->f_ops == &badfileops) { 396 fp->f_type = DTYPE_VNODE; 397 fp->f_ops = &vnops; 398 } 399 vref(vp); 400 } else if ((fmode & FWRITE) != 0) { 401 VOP_ADD_WRITECOUNT(vp, 1); 402 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 403 __func__, vp, vp->v_writecount); 404 } 405 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 406 return (error); 407} 408 409/* 410 * Check for write permissions on the specified vnode. 411 * Prototype text segments cannot be written. 412 */ 413int 414vn_writechk(struct vnode *vp) 415{ 416 417 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 418 /* 419 * If there's shared text associated with 420 * the vnode, try to free it up once. If 421 * we fail, we can't allow writing. 422 */ 423 if (VOP_IS_TEXT(vp)) 424 return (ETXTBSY); 425 426 return (0); 427} 428 429/* 430 * Vnode close call 431 */ 432static int 433vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 434 struct thread *td, bool keep_ref) 435{ 436 struct mount *mp; 437 int error, lock_flags; 438 439 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 440 MNT_EXTENDED_SHARED(vp->v_mount)) 441 lock_flags = LK_SHARED; 442 else 443 lock_flags = LK_EXCLUSIVE; 444 445 vn_start_write(vp, &mp, V_WAIT); 446 vn_lock(vp, lock_flags | LK_RETRY); 447 AUDIT_ARG_VNODE1(vp); 448 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 449 VNASSERT(vp->v_writecount > 0, vp, 450 ("vn_close: negative writecount")); 451 VOP_ADD_WRITECOUNT(vp, -1); 452 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 453 __func__, vp, vp->v_writecount); 454 } 455 error = VOP_CLOSE(vp, flags, file_cred, td); 456 if (keep_ref) 457 VOP_UNLOCK(vp, 0); 458 else 459 vput(vp); 460 vn_finished_write(mp); 461 return (error); 462} 463 464int 465vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 466 struct thread *td) 467{ 468 469 return (vn_close1(vp, flags, file_cred, td, false)); 470} 471 472/* 473 * Heuristic to detect sequential operation. 474 */ 475static int 476sequential_heuristic(struct uio *uio, struct file *fp) 477{ 478 479 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 480 if (fp->f_flag & FRDAHEAD) 481 return (fp->f_seqcount << IO_SEQSHIFT); 482 483 /* 484 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 485 * that the first I/O is normally considered to be slightly 486 * sequential. Seeking to offset 0 doesn't change sequentiality 487 * unless previous seeks have reduced f_seqcount to 0, in which 488 * case offset 0 is not special. 489 */ 490 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 491 uio->uio_offset == fp->f_nextoff) { 492 /* 493 * f_seqcount is in units of fixed-size blocks so that it 494 * depends mainly on the amount of sequential I/O and not 495 * much on the number of sequential I/O's. The fixed size 496 * of 16384 is hard-coded here since it is (not quite) just 497 * a magic size that works well here. This size is more 498 * closely related to the best I/O size for real disks than 499 * to any block size used by software. 500 */ 501 fp->f_seqcount += howmany(uio->uio_resid, 16384); 502 if (fp->f_seqcount > IO_SEQMAX) 503 fp->f_seqcount = IO_SEQMAX; 504 return (fp->f_seqcount << IO_SEQSHIFT); 505 } 506 507 /* Not sequential. Quickly draw-down sequentiality. */ 508 if (fp->f_seqcount > 1) 509 fp->f_seqcount = 1; 510 else 511 fp->f_seqcount = 0; 512 return (0); 513} 514 515/* 516 * Package up an I/O request on a vnode into a uio and do it. 517 */ 518int 519vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 520 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 521 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 522{ 523 struct uio auio; 524 struct iovec aiov; 525 struct mount *mp; 526 struct ucred *cred; 527 void *rl_cookie; 528 struct vn_io_fault_args args; 529 int error, lock_flags; 530 531 auio.uio_iov = &aiov; 532 auio.uio_iovcnt = 1; 533 aiov.iov_base = base; 534 aiov.iov_len = len; 535 auio.uio_resid = len; 536 auio.uio_offset = offset; 537 auio.uio_segflg = segflg; 538 auio.uio_rw = rw; 539 auio.uio_td = td; 540 error = 0; 541 542 if ((ioflg & IO_NODELOCKED) == 0) { 543 if ((ioflg & IO_RANGELOCKED) == 0) { 544 if (rw == UIO_READ) { 545 rl_cookie = vn_rangelock_rlock(vp, offset, 546 offset + len); 547 } else { 548 rl_cookie = vn_rangelock_wlock(vp, offset, 549 offset + len); 550 } 551 } else 552 rl_cookie = NULL; 553 mp = NULL; 554 if (rw == UIO_WRITE) { 555 if (vp->v_type != VCHR && 556 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 557 != 0) 558 goto out; 559 if (MNT_SHARED_WRITES(mp) || 560 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 561 lock_flags = LK_SHARED; 562 else 563 lock_flags = LK_EXCLUSIVE; 564 } else 565 lock_flags = LK_SHARED; 566 vn_lock(vp, lock_flags | LK_RETRY); 567 } else 568 rl_cookie = NULL; 569 570 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 571#ifdef MAC 572 if ((ioflg & IO_NOMACCHECK) == 0) { 573 if (rw == UIO_READ) 574 error = mac_vnode_check_read(active_cred, file_cred, 575 vp); 576 else 577 error = mac_vnode_check_write(active_cred, file_cred, 578 vp); 579 } 580#endif 581 if (error == 0) { 582 if (file_cred != NULL) 583 cred = file_cred; 584 else 585 cred = active_cred; 586 if (do_vn_io_fault(vp, &auio)) { 587 args.kind = VN_IO_FAULT_VOP; 588 args.cred = cred; 589 args.flags = ioflg; 590 args.args.vop_args.vp = vp; 591 error = vn_io_fault1(vp, &auio, &args, td); 592 } else if (rw == UIO_READ) { 593 error = VOP_READ(vp, &auio, ioflg, cred); 594 } else /* if (rw == UIO_WRITE) */ { 595 error = VOP_WRITE(vp, &auio, ioflg, cred); 596 } 597 } 598 if (aresid) 599 *aresid = auio.uio_resid; 600 else 601 if (auio.uio_resid && error == 0) 602 error = EIO; 603 if ((ioflg & IO_NODELOCKED) == 0) { 604 VOP_UNLOCK(vp, 0); 605 if (mp != NULL) 606 vn_finished_write(mp); 607 } 608 out: 609 if (rl_cookie != NULL) 610 vn_rangelock_unlock(vp, rl_cookie); 611 return (error); 612} 613 614/* 615 * Package up an I/O request on a vnode into a uio and do it. The I/O 616 * request is split up into smaller chunks and we try to avoid saturating 617 * the buffer cache while potentially holding a vnode locked, so we 618 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 619 * to give other processes a chance to lock the vnode (either other processes 620 * core'ing the same binary, or unrelated processes scanning the directory). 621 */ 622int 623vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred, 624 file_cred, aresid, td) 625 enum uio_rw rw; 626 struct vnode *vp; 627 void *base; 628 size_t len; 629 off_t offset; 630 enum uio_seg segflg; 631 int ioflg; 632 struct ucred *active_cred; 633 struct ucred *file_cred; 634 size_t *aresid; 635 struct thread *td; 636{ 637 int error = 0; 638 ssize_t iaresid; 639 640 do { 641 int chunk; 642 643 /* 644 * Force `offset' to a multiple of MAXBSIZE except possibly 645 * for the first chunk, so that filesystems only need to 646 * write full blocks except possibly for the first and last 647 * chunks. 648 */ 649 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 650 651 if (chunk > len) 652 chunk = len; 653 if (rw != UIO_READ && vp->v_type == VREG) 654 bwillwrite(); 655 iaresid = 0; 656 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 657 ioflg, active_cred, file_cred, &iaresid, td); 658 len -= chunk; /* aresid calc already includes length */ 659 if (error) 660 break; 661 offset += chunk; 662 base = (char *)base + chunk; 663 kern_yield(PRI_USER); 664 } while (len); 665 if (aresid) 666 *aresid = len + iaresid; 667 return (error); 668} 669 670off_t 671foffset_lock(struct file *fp, int flags) 672{ 673 struct mtx *mtxp; 674 off_t res; 675 676 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 677 678#if OFF_MAX <= LONG_MAX 679 /* 680 * Caller only wants the current f_offset value. Assume that 681 * the long and shorter integer types reads are atomic. 682 */ 683 if ((flags & FOF_NOLOCK) != 0) 684 return (fp->f_offset); 685#endif 686 687 /* 688 * According to McKusick the vn lock was protecting f_offset here. 689 * It is now protected by the FOFFSET_LOCKED flag. 690 */ 691 mtxp = mtx_pool_find(mtxpool_sleep, fp); 692 mtx_lock(mtxp); 693 if ((flags & FOF_NOLOCK) == 0) { 694 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 695 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 696 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 697 "vofflock", 0); 698 } 699 fp->f_vnread_flags |= FOFFSET_LOCKED; 700 } 701 res = fp->f_offset; 702 mtx_unlock(mtxp); 703 return (res); 704} 705 706void 707foffset_unlock(struct file *fp, off_t val, int flags) 708{ 709 struct mtx *mtxp; 710 711 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 712 713#if OFF_MAX <= LONG_MAX 714 if ((flags & FOF_NOLOCK) != 0) { 715 if ((flags & FOF_NOUPDATE) == 0) 716 fp->f_offset = val; 717 if ((flags & FOF_NEXTOFF) != 0) 718 fp->f_nextoff = val; 719 return; 720 } 721#endif 722 723 mtxp = mtx_pool_find(mtxpool_sleep, fp); 724 mtx_lock(mtxp); 725 if ((flags & FOF_NOUPDATE) == 0) 726 fp->f_offset = val; 727 if ((flags & FOF_NEXTOFF) != 0) 728 fp->f_nextoff = val; 729 if ((flags & FOF_NOLOCK) == 0) { 730 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 731 ("Lost FOFFSET_LOCKED")); 732 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 733 wakeup(&fp->f_vnread_flags); 734 fp->f_vnread_flags = 0; 735 } 736 mtx_unlock(mtxp); 737} 738 739void 740foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 741{ 742 743 if ((flags & FOF_OFFSET) == 0) 744 uio->uio_offset = foffset_lock(fp, flags); 745} 746 747void 748foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 749{ 750 751 if ((flags & FOF_OFFSET) == 0) 752 foffset_unlock(fp, uio->uio_offset, flags); 753} 754 755static int 756get_advice(struct file *fp, struct uio *uio) 757{ 758 struct mtx *mtxp; 759 int ret; 760 761 ret = POSIX_FADV_NORMAL; 762 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 763 return (ret); 764 765 mtxp = mtx_pool_find(mtxpool_sleep, fp); 766 mtx_lock(mtxp); 767 if (fp->f_advice != NULL && 768 uio->uio_offset >= fp->f_advice->fa_start && 769 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 770 ret = fp->f_advice->fa_advice; 771 mtx_unlock(mtxp); 772 return (ret); 773} 774 775/* 776 * File table vnode read routine. 777 */ 778static int 779vn_read(fp, uio, active_cred, flags, td) 780 struct file *fp; 781 struct uio *uio; 782 struct ucred *active_cred; 783 int flags; 784 struct thread *td; 785{ 786 struct vnode *vp; 787 off_t orig_offset; 788 int error, ioflag; 789 int advice; 790 791 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 792 uio->uio_td, td)); 793 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 794 vp = fp->f_vnode; 795 ioflag = 0; 796 if (fp->f_flag & FNONBLOCK) 797 ioflag |= IO_NDELAY; 798 if (fp->f_flag & O_DIRECT) 799 ioflag |= IO_DIRECT; 800 advice = get_advice(fp, uio); 801 vn_lock(vp, LK_SHARED | LK_RETRY); 802 803 switch (advice) { 804 case POSIX_FADV_NORMAL: 805 case POSIX_FADV_SEQUENTIAL: 806 case POSIX_FADV_NOREUSE: 807 ioflag |= sequential_heuristic(uio, fp); 808 break; 809 case POSIX_FADV_RANDOM: 810 /* Disable read-ahead for random I/O. */ 811 break; 812 } 813 orig_offset = uio->uio_offset; 814 815#ifdef MAC 816 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 817 if (error == 0) 818#endif 819 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 820 fp->f_nextoff = uio->uio_offset; 821 VOP_UNLOCK(vp, 0); 822 if (error == 0 && advice == POSIX_FADV_NOREUSE && 823 orig_offset != uio->uio_offset) 824 /* 825 * Use POSIX_FADV_DONTNEED to flush pages and buffers 826 * for the backing file after a POSIX_FADV_NOREUSE 827 * read(2). 828 */ 829 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 830 POSIX_FADV_DONTNEED); 831 return (error); 832} 833 834/* 835 * File table vnode write routine. 836 */ 837static int 838vn_write(fp, uio, active_cred, flags, td) 839 struct file *fp; 840 struct uio *uio; 841 struct ucred *active_cred; 842 int flags; 843 struct thread *td; 844{ 845 struct vnode *vp; 846 struct mount *mp; 847 off_t orig_offset; 848 int error, ioflag, lock_flags; 849 int advice; 850 851 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 852 uio->uio_td, td)); 853 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 854 vp = fp->f_vnode; 855 if (vp->v_type == VREG) 856 bwillwrite(); 857 ioflag = IO_UNIT; 858 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 859 ioflag |= IO_APPEND; 860 if (fp->f_flag & FNONBLOCK) 861 ioflag |= IO_NDELAY; 862 if (fp->f_flag & O_DIRECT) 863 ioflag |= IO_DIRECT; 864 if ((fp->f_flag & O_FSYNC) || 865 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 866 ioflag |= IO_SYNC; 867 mp = NULL; 868 if (vp->v_type != VCHR && 869 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 870 goto unlock; 871 872 advice = get_advice(fp, uio); 873 874 if (MNT_SHARED_WRITES(mp) || 875 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 876 lock_flags = LK_SHARED; 877 } else { 878 lock_flags = LK_EXCLUSIVE; 879 } 880 881 vn_lock(vp, lock_flags | LK_RETRY); 882 switch (advice) { 883 case POSIX_FADV_NORMAL: 884 case POSIX_FADV_SEQUENTIAL: 885 case POSIX_FADV_NOREUSE: 886 ioflag |= sequential_heuristic(uio, fp); 887 break; 888 case POSIX_FADV_RANDOM: 889 /* XXX: Is this correct? */ 890 break; 891 } 892 orig_offset = uio->uio_offset; 893 894#ifdef MAC 895 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 896 if (error == 0) 897#endif 898 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 899 fp->f_nextoff = uio->uio_offset; 900 VOP_UNLOCK(vp, 0); 901 if (vp->v_type != VCHR) 902 vn_finished_write(mp); 903 if (error == 0 && advice == POSIX_FADV_NOREUSE && 904 orig_offset != uio->uio_offset) 905 /* 906 * Use POSIX_FADV_DONTNEED to flush pages and buffers 907 * for the backing file after a POSIX_FADV_NOREUSE 908 * write(2). 909 */ 910 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 911 POSIX_FADV_DONTNEED); 912unlock: 913 return (error); 914} 915 916/* 917 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 918 * prevent the following deadlock: 919 * 920 * Assume that the thread A reads from the vnode vp1 into userspace 921 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 922 * currently not resident, then system ends up with the call chain 923 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 924 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 925 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 926 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 927 * backed by the pages of vnode vp1, and some page in buf2 is not 928 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 929 * 930 * To prevent the lock order reversal and deadlock, vn_io_fault() does 931 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 932 * Instead, it first tries to do the whole range i/o with pagefaults 933 * disabled. If all pages in the i/o buffer are resident and mapped, 934 * VOP will succeed (ignoring the genuine filesystem errors). 935 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 936 * i/o in chunks, with all pages in the chunk prefaulted and held 937 * using vm_fault_quick_hold_pages(). 938 * 939 * Filesystems using this deadlock avoidance scheme should use the 940 * array of the held pages from uio, saved in the curthread->td_ma, 941 * instead of doing uiomove(). A helper function 942 * vn_io_fault_uiomove() converts uiomove request into 943 * uiomove_fromphys() over td_ma array. 944 * 945 * Since vnode locks do not cover the whole i/o anymore, rangelocks 946 * make the current i/o request atomic with respect to other i/os and 947 * truncations. 948 */ 949 950/* 951 * Decode vn_io_fault_args and perform the corresponding i/o. 952 */ 953static int 954vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 955 struct thread *td) 956{ 957 958 switch (args->kind) { 959 case VN_IO_FAULT_FOP: 960 return ((args->args.fop_args.doio)(args->args.fop_args.fp, 961 uio, args->cred, args->flags, td)); 962 case VN_IO_FAULT_VOP: 963 if (uio->uio_rw == UIO_READ) { 964 return (VOP_READ(args->args.vop_args.vp, uio, 965 args->flags, args->cred)); 966 } else if (uio->uio_rw == UIO_WRITE) { 967 return (VOP_WRITE(args->args.vop_args.vp, uio, 968 args->flags, args->cred)); 969 } 970 break; 971 } 972 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind, 973 uio->uio_rw); 974} 975 976static int 977vn_io_fault_touch(char *base, const struct uio *uio) 978{ 979 int r; 980 981 r = fubyte(base); 982 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 983 return (EFAULT); 984 return (0); 985} 986 987static int 988vn_io_fault_prefault_user(const struct uio *uio) 989{ 990 char *base; 991 const struct iovec *iov; 992 size_t len; 993 ssize_t resid; 994 int error, i; 995 996 KASSERT(uio->uio_segflg == UIO_USERSPACE, 997 ("vn_io_fault_prefault userspace")); 998 999 error = i = 0; 1000 iov = uio->uio_iov; 1001 resid = uio->uio_resid; 1002 base = iov->iov_base; 1003 len = iov->iov_len; 1004 while (resid > 0) { 1005 error = vn_io_fault_touch(base, uio); 1006 if (error != 0) 1007 break; 1008 if (len < PAGE_SIZE) { 1009 if (len != 0) { 1010 error = vn_io_fault_touch(base + len - 1, uio); 1011 if (error != 0) 1012 break; 1013 resid -= len; 1014 } 1015 if (++i >= uio->uio_iovcnt) 1016 break; 1017 iov = uio->uio_iov + i; 1018 base = iov->iov_base; 1019 len = iov->iov_len; 1020 } else { 1021 len -= PAGE_SIZE; 1022 base += PAGE_SIZE; 1023 resid -= PAGE_SIZE; 1024 } 1025 } 1026 return (error); 1027} 1028 1029/* 1030 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1031 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1032 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1033 * into args and call vn_io_fault1() to handle faults during the user 1034 * mode buffer accesses. 1035 */ 1036static int 1037vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1038 struct thread *td) 1039{ 1040 vm_page_t ma[io_hold_cnt + 2]; 1041 struct uio *uio_clone, short_uio; 1042 struct iovec short_iovec[1]; 1043 vm_page_t *prev_td_ma; 1044 vm_prot_t prot; 1045 vm_offset_t addr, end; 1046 size_t len, resid; 1047 ssize_t adv; 1048 int error, cnt, save, saveheld, prev_td_ma_cnt; 1049 1050 if (vn_io_fault_prefault) { 1051 error = vn_io_fault_prefault_user(uio); 1052 if (error != 0) 1053 return (error); /* Or ignore ? */ 1054 } 1055 1056 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1057 1058 /* 1059 * The UFS follows IO_UNIT directive and replays back both 1060 * uio_offset and uio_resid if an error is encountered during the 1061 * operation. But, since the iovec may be already advanced, 1062 * uio is still in an inconsistent state. 1063 * 1064 * Cache a copy of the original uio, which is advanced to the redo 1065 * point using UIO_NOCOPY below. 1066 */ 1067 uio_clone = cloneuio(uio); 1068 resid = uio->uio_resid; 1069 1070 short_uio.uio_segflg = UIO_USERSPACE; 1071 short_uio.uio_rw = uio->uio_rw; 1072 short_uio.uio_td = uio->uio_td; 1073 1074 save = vm_fault_disable_pagefaults(); 1075 error = vn_io_fault_doio(args, uio, td); 1076 if (error != EFAULT) 1077 goto out; 1078 1079 atomic_add_long(&vn_io_faults_cnt, 1); 1080 uio_clone->uio_segflg = UIO_NOCOPY; 1081 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1082 uio_clone->uio_segflg = uio->uio_segflg; 1083 1084 saveheld = curthread_pflags_set(TDP_UIOHELD); 1085 prev_td_ma = td->td_ma; 1086 prev_td_ma_cnt = td->td_ma_cnt; 1087 1088 while (uio_clone->uio_resid != 0) { 1089 len = uio_clone->uio_iov->iov_len; 1090 if (len == 0) { 1091 KASSERT(uio_clone->uio_iovcnt >= 1, 1092 ("iovcnt underflow")); 1093 uio_clone->uio_iov++; 1094 uio_clone->uio_iovcnt--; 1095 continue; 1096 } 1097 if (len > io_hold_cnt * PAGE_SIZE) 1098 len = io_hold_cnt * PAGE_SIZE; 1099 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1100 end = round_page(addr + len); 1101 if (end < addr) { 1102 error = EFAULT; 1103 break; 1104 } 1105 cnt = atop(end - trunc_page(addr)); 1106 /* 1107 * A perfectly misaligned address and length could cause 1108 * both the start and the end of the chunk to use partial 1109 * page. +2 accounts for such a situation. 1110 */ 1111 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1112 addr, len, prot, ma, io_hold_cnt + 2); 1113 if (cnt == -1) { 1114 error = EFAULT; 1115 break; 1116 } 1117 short_uio.uio_iov = &short_iovec[0]; 1118 short_iovec[0].iov_base = (void *)addr; 1119 short_uio.uio_iovcnt = 1; 1120 short_uio.uio_resid = short_iovec[0].iov_len = len; 1121 short_uio.uio_offset = uio_clone->uio_offset; 1122 td->td_ma = ma; 1123 td->td_ma_cnt = cnt; 1124 1125 error = vn_io_fault_doio(args, &short_uio, td); 1126 vm_page_unhold_pages(ma, cnt); 1127 adv = len - short_uio.uio_resid; 1128 1129 uio_clone->uio_iov->iov_base = 1130 (char *)uio_clone->uio_iov->iov_base + adv; 1131 uio_clone->uio_iov->iov_len -= adv; 1132 uio_clone->uio_resid -= adv; 1133 uio_clone->uio_offset += adv; 1134 1135 uio->uio_resid -= adv; 1136 uio->uio_offset += adv; 1137 1138 if (error != 0 || adv == 0) 1139 break; 1140 } 1141 td->td_ma = prev_td_ma; 1142 td->td_ma_cnt = prev_td_ma_cnt; 1143 curthread_pflags_restore(saveheld); 1144out: 1145 vm_fault_enable_pagefaults(save); 1146 free(uio_clone, M_IOV); 1147 return (error); 1148} 1149 1150static int 1151vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1152 int flags, struct thread *td) 1153{ 1154 fo_rdwr_t *doio; 1155 struct vnode *vp; 1156 void *rl_cookie; 1157 struct vn_io_fault_args args; 1158 int error; 1159 1160 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1161 vp = fp->f_vnode; 1162 foffset_lock_uio(fp, uio, flags); 1163 if (do_vn_io_fault(vp, uio)) { 1164 args.kind = VN_IO_FAULT_FOP; 1165 args.args.fop_args.fp = fp; 1166 args.args.fop_args.doio = doio; 1167 args.cred = active_cred; 1168 args.flags = flags | FOF_OFFSET; 1169 if (uio->uio_rw == UIO_READ) { 1170 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1171 uio->uio_offset + uio->uio_resid); 1172 } else if ((fp->f_flag & O_APPEND) != 0 || 1173 (flags & FOF_OFFSET) == 0) { 1174 /* For appenders, punt and lock the whole range. */ 1175 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1176 } else { 1177 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1178 uio->uio_offset + uio->uio_resid); 1179 } 1180 error = vn_io_fault1(vp, uio, &args, td); 1181 vn_rangelock_unlock(vp, rl_cookie); 1182 } else { 1183 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1184 } 1185 foffset_unlock_uio(fp, uio, flags); 1186 return (error); 1187} 1188 1189/* 1190 * Helper function to perform the requested uiomove operation using 1191 * the held pages for io->uio_iov[0].iov_base buffer instead of 1192 * copyin/copyout. Access to the pages with uiomove_fromphys() 1193 * instead of iov_base prevents page faults that could occur due to 1194 * pmap_collect() invalidating the mapping created by 1195 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1196 * object cleanup revoking the write access from page mappings. 1197 * 1198 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1199 * instead of plain uiomove(). 1200 */ 1201int 1202vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1203{ 1204 struct uio transp_uio; 1205 struct iovec transp_iov[1]; 1206 struct thread *td; 1207 size_t adv; 1208 int error, pgadv; 1209 1210 td = curthread; 1211 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1212 uio->uio_segflg != UIO_USERSPACE) 1213 return (uiomove(data, xfersize, uio)); 1214 1215 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1216 transp_iov[0].iov_base = data; 1217 transp_uio.uio_iov = &transp_iov[0]; 1218 transp_uio.uio_iovcnt = 1; 1219 if (xfersize > uio->uio_resid) 1220 xfersize = uio->uio_resid; 1221 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1222 transp_uio.uio_offset = 0; 1223 transp_uio.uio_segflg = UIO_SYSSPACE; 1224 /* 1225 * Since transp_iov points to data, and td_ma page array 1226 * corresponds to original uio->uio_iov, we need to invert the 1227 * direction of the i/o operation as passed to 1228 * uiomove_fromphys(). 1229 */ 1230 switch (uio->uio_rw) { 1231 case UIO_WRITE: 1232 transp_uio.uio_rw = UIO_READ; 1233 break; 1234 case UIO_READ: 1235 transp_uio.uio_rw = UIO_WRITE; 1236 break; 1237 } 1238 transp_uio.uio_td = uio->uio_td; 1239 error = uiomove_fromphys(td->td_ma, 1240 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1241 xfersize, &transp_uio); 1242 adv = xfersize - transp_uio.uio_resid; 1243 pgadv = 1244 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1245 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1246 td->td_ma += pgadv; 1247 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1248 pgadv)); 1249 td->td_ma_cnt -= pgadv; 1250 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1251 uio->uio_iov->iov_len -= adv; 1252 uio->uio_resid -= adv; 1253 uio->uio_offset += adv; 1254 return (error); 1255} 1256 1257int 1258vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1259 struct uio *uio) 1260{ 1261 struct thread *td; 1262 vm_offset_t iov_base; 1263 int cnt, pgadv; 1264 1265 td = curthread; 1266 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1267 uio->uio_segflg != UIO_USERSPACE) 1268 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1269 1270 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1271 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1272 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1273 switch (uio->uio_rw) { 1274 case UIO_WRITE: 1275 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1276 offset, cnt); 1277 break; 1278 case UIO_READ: 1279 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1280 cnt); 1281 break; 1282 } 1283 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1284 td->td_ma += pgadv; 1285 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1286 pgadv)); 1287 td->td_ma_cnt -= pgadv; 1288 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1289 uio->uio_iov->iov_len -= cnt; 1290 uio->uio_resid -= cnt; 1291 uio->uio_offset += cnt; 1292 return (0); 1293} 1294 1295 1296/* 1297 * File table truncate routine. 1298 */ 1299static int 1300vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1301 struct thread *td) 1302{ 1303 struct vattr vattr; 1304 struct mount *mp; 1305 struct vnode *vp; 1306 void *rl_cookie; 1307 int error; 1308 1309 vp = fp->f_vnode; 1310 1311 /* 1312 * Lock the whole range for truncation. Otherwise split i/o 1313 * might happen partly before and partly after the truncation. 1314 */ 1315 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1316 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1317 if (error) 1318 goto out1; 1319 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1320 if (vp->v_type == VDIR) { 1321 error = EISDIR; 1322 goto out; 1323 } 1324#ifdef MAC 1325 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1326 if (error) 1327 goto out; 1328#endif 1329 error = vn_writechk(vp); 1330 if (error == 0) { 1331 VATTR_NULL(&vattr); 1332 vattr.va_size = length; 1333 if ((fp->f_flag & O_FSYNC) != 0) 1334 vattr.va_vaflags |= VA_SYNC; 1335 error = VOP_SETATTR(vp, &vattr, fp->f_cred); 1336 } 1337out: 1338 VOP_UNLOCK(vp, 0); 1339 vn_finished_write(mp); 1340out1: 1341 vn_rangelock_unlock(vp, rl_cookie); 1342 return (error); 1343} 1344 1345/* 1346 * File table vnode stat routine. 1347 */ 1348static int 1349vn_statfile(fp, sb, active_cred, td) 1350 struct file *fp; 1351 struct stat *sb; 1352 struct ucred *active_cred; 1353 struct thread *td; 1354{ 1355 struct vnode *vp = fp->f_vnode; 1356 int error; 1357 1358 vn_lock(vp, LK_SHARED | LK_RETRY); 1359 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 1360 VOP_UNLOCK(vp, 0); 1361 1362 return (error); 1363} 1364 1365/* 1366 * Stat a vnode; implementation for the stat syscall 1367 */ 1368int 1369vn_stat(struct vnode *vp, struct stat *sb, struct ucred *active_cred, 1370 struct ucred *file_cred, struct thread *td) 1371{ 1372 struct vattr vattr; 1373 struct vattr *vap; 1374 int error; 1375 u_short mode; 1376 1377 AUDIT_ARG_VNODE1(vp); 1378#ifdef MAC 1379 error = mac_vnode_check_stat(active_cred, file_cred, vp); 1380 if (error) 1381 return (error); 1382#endif 1383 1384 vap = &vattr; 1385 1386 /* 1387 * Initialize defaults for new and unusual fields, so that file 1388 * systems which don't support these fields don't need to know 1389 * about them. 1390 */ 1391 vap->va_birthtime.tv_sec = -1; 1392 vap->va_birthtime.tv_nsec = 0; 1393 vap->va_fsid = VNOVAL; 1394 vap->va_rdev = NODEV; 1395 1396 error = VOP_GETATTR(vp, vap, active_cred); 1397 if (error) 1398 return (error); 1399 1400 /* 1401 * Zero the spare stat fields 1402 */ 1403 bzero(sb, sizeof *sb); 1404 1405 /* 1406 * Copy from vattr table 1407 */ 1408 if (vap->va_fsid != VNOVAL) 1409 sb->st_dev = vap->va_fsid; 1410 else 1411 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 1412 sb->st_ino = vap->va_fileid; 1413 mode = vap->va_mode; 1414 switch (vap->va_type) { 1415 case VREG: 1416 mode |= S_IFREG; 1417 break; 1418 case VDIR: 1419 mode |= S_IFDIR; 1420 break; 1421 case VBLK: 1422 mode |= S_IFBLK; 1423 break; 1424 case VCHR: 1425 mode |= S_IFCHR; 1426 break; 1427 case VLNK: 1428 mode |= S_IFLNK; 1429 break; 1430 case VSOCK: 1431 mode |= S_IFSOCK; 1432 break; 1433 case VFIFO: 1434 mode |= S_IFIFO; 1435 break; 1436 default: 1437 return (EBADF); 1438 } 1439 sb->st_mode = mode; 1440 sb->st_nlink = vap->va_nlink; 1441 sb->st_uid = vap->va_uid; 1442 sb->st_gid = vap->va_gid; 1443 sb->st_rdev = vap->va_rdev; 1444 if (vap->va_size > OFF_MAX) 1445 return (EOVERFLOW); 1446 sb->st_size = vap->va_size; 1447 sb->st_atim = vap->va_atime; 1448 sb->st_mtim = vap->va_mtime; 1449 sb->st_ctim = vap->va_ctime; 1450 sb->st_birthtim = vap->va_birthtime; 1451 1452 /* 1453 * According to www.opengroup.org, the meaning of st_blksize is 1454 * "a filesystem-specific preferred I/O block size for this 1455 * object. In some filesystem types, this may vary from file 1456 * to file" 1457 * Use miminum/default of PAGE_SIZE (e.g. for VCHR). 1458 */ 1459 1460 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize); 1461 1462 sb->st_flags = vap->va_flags; 1463 if (priv_check(td, PRIV_VFS_GENERATION)) 1464 sb->st_gen = 0; 1465 else 1466 sb->st_gen = vap->va_gen; 1467 1468 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 1469 return (0); 1470} 1471 1472/* 1473 * File table vnode ioctl routine. 1474 */ 1475static int 1476vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1477 struct thread *td) 1478{ 1479 struct vattr vattr; 1480 struct vnode *vp; 1481 int error; 1482 1483 vp = fp->f_vnode; 1484 switch (vp->v_type) { 1485 case VDIR: 1486 case VREG: 1487 switch (com) { 1488 case FIONREAD: 1489 vn_lock(vp, LK_SHARED | LK_RETRY); 1490 error = VOP_GETATTR(vp, &vattr, active_cred); 1491 VOP_UNLOCK(vp, 0); 1492 if (error == 0) 1493 *(int *)data = vattr.va_size - fp->f_offset; 1494 return (error); 1495 case FIONBIO: 1496 case FIOASYNC: 1497 return (0); 1498 default: 1499 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1500 active_cred, td)); 1501 } 1502 default: 1503 return (ENOTTY); 1504 } 1505} 1506 1507/* 1508 * File table vnode poll routine. 1509 */ 1510static int 1511vn_poll(struct file *fp, int events, struct ucred *active_cred, 1512 struct thread *td) 1513{ 1514 struct vnode *vp; 1515 int error; 1516 1517 vp = fp->f_vnode; 1518#ifdef MAC 1519 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1520 AUDIT_ARG_VNODE1(vp); 1521 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1522 VOP_UNLOCK(vp, 0); 1523 if (!error) 1524#endif 1525 1526 error = VOP_POLL(vp, events, fp->f_cred, td); 1527 return (error); 1528} 1529 1530/* 1531 * Acquire the requested lock and then check for validity. LK_RETRY 1532 * permits vn_lock to return doomed vnodes. 1533 */ 1534int 1535_vn_lock(struct vnode *vp, int flags, char *file, int line) 1536{ 1537 int error; 1538 1539 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1540 ("vn_lock: no locktype")); 1541 VNASSERT(vp->v_holdcnt != 0, vp, ("vn_lock: zero hold count")); 1542retry: 1543 error = VOP_LOCK1(vp, flags, file, line); 1544 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ 1545 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1546 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1547 1548 if ((flags & LK_RETRY) == 0) { 1549 if (error == 0 && (vp->v_iflag & VI_DOOMED) != 0) { 1550 VOP_UNLOCK(vp, 0); 1551 error = ENOENT; 1552 } 1553 } else if (error != 0) 1554 goto retry; 1555 return (error); 1556} 1557 1558/* 1559 * File table vnode close routine. 1560 */ 1561static int 1562vn_closefile(struct file *fp, struct thread *td) 1563{ 1564 struct vnode *vp; 1565 struct flock lf; 1566 int error; 1567 bool ref; 1568 1569 vp = fp->f_vnode; 1570 fp->f_ops = &badfileops; 1571 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1572 1573 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1574 1575 if (__predict_false(ref)) { 1576 lf.l_whence = SEEK_SET; 1577 lf.l_start = 0; 1578 lf.l_len = 0; 1579 lf.l_type = F_UNLCK; 1580 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1581 vrele(vp); 1582 } 1583 return (error); 1584} 1585 1586static bool 1587vn_suspendable(struct mount *mp) 1588{ 1589 1590 return (mp->mnt_op->vfs_susp_clean != NULL); 1591} 1592 1593/* 1594 * Preparing to start a filesystem write operation. If the operation is 1595 * permitted, then we bump the count of operations in progress and 1596 * proceed. If a suspend request is in progress, we wait until the 1597 * suspension is over, and then proceed. 1598 */ 1599static int 1600vn_start_write_locked(struct mount *mp, int flags) 1601{ 1602 int error, mflags; 1603 1604 mtx_assert(MNT_MTX(mp), MA_OWNED); 1605 error = 0; 1606 1607 /* 1608 * Check on status of suspension. 1609 */ 1610 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1611 mp->mnt_susp_owner != curthread) { 1612 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1613 (flags & PCATCH) : 0) | (PUSER - 1); 1614 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1615 if (flags & V_NOWAIT) { 1616 error = EWOULDBLOCK; 1617 goto unlock; 1618 } 1619 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1620 "suspfs", 0); 1621 if (error) 1622 goto unlock; 1623 } 1624 } 1625 if (flags & V_XSLEEP) 1626 goto unlock; 1627 mp->mnt_writeopcount++; 1628unlock: 1629 if (error != 0 || (flags & V_XSLEEP) != 0) 1630 MNT_REL(mp); 1631 MNT_IUNLOCK(mp); 1632 return (error); 1633} 1634 1635int 1636vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1637{ 1638 struct mount *mp; 1639 int error; 1640 1641 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1642 ("V_MNTREF requires mp")); 1643 1644 error = 0; 1645 /* 1646 * If a vnode is provided, get and return the mount point that 1647 * to which it will write. 1648 */ 1649 if (vp != NULL) { 1650 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1651 *mpp = NULL; 1652 if (error != EOPNOTSUPP) 1653 return (error); 1654 return (0); 1655 } 1656 } 1657 if ((mp = *mpp) == NULL) 1658 return (0); 1659 1660 if (!vn_suspendable(mp)) { 1661 if (vp != NULL || (flags & V_MNTREF) != 0) 1662 vfs_rel(mp); 1663 return (0); 1664 } 1665 1666 /* 1667 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1668 * a vfs_ref(). 1669 * As long as a vnode is not provided we need to acquire a 1670 * refcount for the provided mountpoint too, in order to 1671 * emulate a vfs_ref(). 1672 */ 1673 MNT_ILOCK(mp); 1674 if (vp == NULL && (flags & V_MNTREF) == 0) 1675 MNT_REF(mp); 1676 1677 return (vn_start_write_locked(mp, flags)); 1678} 1679 1680/* 1681 * Secondary suspension. Used by operations such as vop_inactive 1682 * routines that are needed by the higher level functions. These 1683 * are allowed to proceed until all the higher level functions have 1684 * completed (indicated by mnt_writeopcount dropping to zero). At that 1685 * time, these operations are halted until the suspension is over. 1686 */ 1687int 1688vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1689{ 1690 struct mount *mp; 1691 int error; 1692 1693 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1694 ("V_MNTREF requires mp")); 1695 1696 retry: 1697 if (vp != NULL) { 1698 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1699 *mpp = NULL; 1700 if (error != EOPNOTSUPP) 1701 return (error); 1702 return (0); 1703 } 1704 } 1705 /* 1706 * If we are not suspended or have not yet reached suspended 1707 * mode, then let the operation proceed. 1708 */ 1709 if ((mp = *mpp) == NULL) 1710 return (0); 1711 1712 if (!vn_suspendable(mp)) { 1713 if (vp != NULL || (flags & V_MNTREF) != 0) 1714 vfs_rel(mp); 1715 return (0); 1716 } 1717 1718 /* 1719 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1720 * a vfs_ref(). 1721 * As long as a vnode is not provided we need to acquire a 1722 * refcount for the provided mountpoint too, in order to 1723 * emulate a vfs_ref(). 1724 */ 1725 MNT_ILOCK(mp); 1726 if (vp == NULL && (flags & V_MNTREF) == 0) 1727 MNT_REF(mp); 1728 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1729 mp->mnt_secondary_writes++; 1730 mp->mnt_secondary_accwrites++; 1731 MNT_IUNLOCK(mp); 1732 return (0); 1733 } 1734 if (flags & V_NOWAIT) { 1735 MNT_REL(mp); 1736 MNT_IUNLOCK(mp); 1737 return (EWOULDBLOCK); 1738 } 1739 /* 1740 * Wait for the suspension to finish. 1741 */ 1742 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1743 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1744 "suspfs", 0); 1745 vfs_rel(mp); 1746 if (error == 0) 1747 goto retry; 1748 return (error); 1749} 1750 1751/* 1752 * Filesystem write operation has completed. If we are suspending and this 1753 * operation is the last one, notify the suspender that the suspension is 1754 * now in effect. 1755 */ 1756void 1757vn_finished_write(struct mount *mp) 1758{ 1759 if (mp == NULL || !vn_suspendable(mp)) 1760 return; 1761 MNT_ILOCK(mp); 1762 MNT_REL(mp); 1763 mp->mnt_writeopcount--; 1764 if (mp->mnt_writeopcount < 0) 1765 panic("vn_finished_write: neg cnt"); 1766 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1767 mp->mnt_writeopcount <= 0) 1768 wakeup(&mp->mnt_writeopcount); 1769 MNT_IUNLOCK(mp); 1770} 1771 1772 1773/* 1774 * Filesystem secondary write operation has completed. If we are 1775 * suspending and this operation is the last one, notify the suspender 1776 * that the suspension is now in effect. 1777 */ 1778void 1779vn_finished_secondary_write(struct mount *mp) 1780{ 1781 if (mp == NULL || !vn_suspendable(mp)) 1782 return; 1783 MNT_ILOCK(mp); 1784 MNT_REL(mp); 1785 mp->mnt_secondary_writes--; 1786 if (mp->mnt_secondary_writes < 0) 1787 panic("vn_finished_secondary_write: neg cnt"); 1788 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1789 mp->mnt_secondary_writes <= 0) 1790 wakeup(&mp->mnt_secondary_writes); 1791 MNT_IUNLOCK(mp); 1792} 1793 1794 1795 1796/* 1797 * Request a filesystem to suspend write operations. 1798 */ 1799int 1800vfs_write_suspend(struct mount *mp, int flags) 1801{ 1802 int error; 1803 1804 MPASS(vn_suspendable(mp)); 1805 1806 MNT_ILOCK(mp); 1807 if (mp->mnt_susp_owner == curthread) { 1808 MNT_IUNLOCK(mp); 1809 return (EALREADY); 1810 } 1811 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1812 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1813 1814 /* 1815 * Unmount holds a write reference on the mount point. If we 1816 * own busy reference and drain for writers, we deadlock with 1817 * the reference draining in the unmount path. Callers of 1818 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 1819 * vfs_busy() reference is owned and caller is not in the 1820 * unmount context. 1821 */ 1822 if ((flags & VS_SKIP_UNMOUNT) != 0 && 1823 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 1824 MNT_IUNLOCK(mp); 1825 return (EBUSY); 1826 } 1827 1828 mp->mnt_kern_flag |= MNTK_SUSPEND; 1829 mp->mnt_susp_owner = curthread; 1830 if (mp->mnt_writeopcount > 0) 1831 (void) msleep(&mp->mnt_writeopcount, 1832 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1833 else 1834 MNT_IUNLOCK(mp); 1835 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) 1836 vfs_write_resume(mp, 0); 1837 return (error); 1838} 1839 1840/* 1841 * Request a filesystem to resume write operations. 1842 */ 1843void 1844vfs_write_resume(struct mount *mp, int flags) 1845{ 1846 1847 MPASS(vn_suspendable(mp)); 1848 1849 MNT_ILOCK(mp); 1850 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1851 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1852 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1853 MNTK_SUSPENDED); 1854 mp->mnt_susp_owner = NULL; 1855 wakeup(&mp->mnt_writeopcount); 1856 wakeup(&mp->mnt_flag); 1857 curthread->td_pflags &= ~TDP_IGNSUSP; 1858 if ((flags & VR_START_WRITE) != 0) { 1859 MNT_REF(mp); 1860 mp->mnt_writeopcount++; 1861 } 1862 MNT_IUNLOCK(mp); 1863 if ((flags & VR_NO_SUSPCLR) == 0) 1864 VFS_SUSP_CLEAN(mp); 1865 } else if ((flags & VR_START_WRITE) != 0) { 1866 MNT_REF(mp); 1867 vn_start_write_locked(mp, 0); 1868 } else { 1869 MNT_IUNLOCK(mp); 1870 } 1871} 1872 1873/* 1874 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 1875 * methods. 1876 */ 1877int 1878vfs_write_suspend_umnt(struct mount *mp) 1879{ 1880 int error; 1881 1882 MPASS(vn_suspendable(mp)); 1883 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 1884 ("vfs_write_suspend_umnt: recursed")); 1885 1886 /* dounmount() already called vn_start_write(). */ 1887 for (;;) { 1888 vn_finished_write(mp); 1889 error = vfs_write_suspend(mp, 0); 1890 if (error != 0) { 1891 vn_start_write(NULL, &mp, V_WAIT); 1892 return (error); 1893 } 1894 MNT_ILOCK(mp); 1895 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 1896 break; 1897 MNT_IUNLOCK(mp); 1898 vn_start_write(NULL, &mp, V_WAIT); 1899 } 1900 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 1901 wakeup(&mp->mnt_flag); 1902 MNT_IUNLOCK(mp); 1903 curthread->td_pflags |= TDP_IGNSUSP; 1904 return (0); 1905} 1906 1907/* 1908 * Implement kqueues for files by translating it to vnode operation. 1909 */ 1910static int 1911vn_kqfilter(struct file *fp, struct knote *kn) 1912{ 1913 1914 return (VOP_KQFILTER(fp->f_vnode, kn)); 1915} 1916 1917/* 1918 * Simplified in-kernel wrapper calls for extended attribute access. 1919 * Both calls pass in a NULL credential, authorizing as "kernel" access. 1920 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 1921 */ 1922int 1923vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 1924 const char *attrname, int *buflen, char *buf, struct thread *td) 1925{ 1926 struct uio auio; 1927 struct iovec iov; 1928 int error; 1929 1930 iov.iov_len = *buflen; 1931 iov.iov_base = buf; 1932 1933 auio.uio_iov = &iov; 1934 auio.uio_iovcnt = 1; 1935 auio.uio_rw = UIO_READ; 1936 auio.uio_segflg = UIO_SYSSPACE; 1937 auio.uio_td = td; 1938 auio.uio_offset = 0; 1939 auio.uio_resid = *buflen; 1940 1941 if ((ioflg & IO_NODELOCKED) == 0) 1942 vn_lock(vp, LK_SHARED | LK_RETRY); 1943 1944 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1945 1946 /* authorize attribute retrieval as kernel */ 1947 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 1948 td); 1949 1950 if ((ioflg & IO_NODELOCKED) == 0) 1951 VOP_UNLOCK(vp, 0); 1952 1953 if (error == 0) { 1954 *buflen = *buflen - auio.uio_resid; 1955 } 1956 1957 return (error); 1958} 1959 1960/* 1961 * XXX failure mode if partially written? 1962 */ 1963int 1964vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 1965 const char *attrname, int buflen, char *buf, struct thread *td) 1966{ 1967 struct uio auio; 1968 struct iovec iov; 1969 struct mount *mp; 1970 int error; 1971 1972 iov.iov_len = buflen; 1973 iov.iov_base = buf; 1974 1975 auio.uio_iov = &iov; 1976 auio.uio_iovcnt = 1; 1977 auio.uio_rw = UIO_WRITE; 1978 auio.uio_segflg = UIO_SYSSPACE; 1979 auio.uio_td = td; 1980 auio.uio_offset = 0; 1981 auio.uio_resid = buflen; 1982 1983 if ((ioflg & IO_NODELOCKED) == 0) { 1984 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 1985 return (error); 1986 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1987 } 1988 1989 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1990 1991 /* authorize attribute setting as kernel */ 1992 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 1993 1994 if ((ioflg & IO_NODELOCKED) == 0) { 1995 vn_finished_write(mp); 1996 VOP_UNLOCK(vp, 0); 1997 } 1998 1999 return (error); 2000} 2001 2002int 2003vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2004 const char *attrname, struct thread *td) 2005{ 2006 struct mount *mp; 2007 int error; 2008 2009 if ((ioflg & IO_NODELOCKED) == 0) { 2010 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2011 return (error); 2012 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2013 } 2014 2015 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2016 2017 /* authorize attribute removal as kernel */ 2018 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2019 if (error == EOPNOTSUPP) 2020 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2021 NULL, td); 2022 2023 if ((ioflg & IO_NODELOCKED) == 0) { 2024 vn_finished_write(mp); 2025 VOP_UNLOCK(vp, 0); 2026 } 2027 2028 return (error); 2029} 2030 2031static int 2032vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2033 struct vnode **rvp) 2034{ 2035 2036 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2037} 2038 2039int 2040vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2041{ 2042 2043 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2044 lkflags, rvp)); 2045} 2046 2047int 2048vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2049 int lkflags, struct vnode **rvp) 2050{ 2051 struct mount *mp; 2052 int ltype, error; 2053 2054 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2055 mp = vp->v_mount; 2056 ltype = VOP_ISLOCKED(vp); 2057 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2058 ("vn_vget_ino: vp not locked")); 2059 error = vfs_busy(mp, MBF_NOWAIT); 2060 if (error != 0) { 2061 vfs_ref(mp); 2062 VOP_UNLOCK(vp, 0); 2063 error = vfs_busy(mp, 0); 2064 vn_lock(vp, ltype | LK_RETRY); 2065 vfs_rel(mp); 2066 if (error != 0) 2067 return (ENOENT); 2068 if (vp->v_iflag & VI_DOOMED) { 2069 vfs_unbusy(mp); 2070 return (ENOENT); 2071 } 2072 } 2073 VOP_UNLOCK(vp, 0); 2074 error = alloc(mp, alloc_arg, lkflags, rvp); 2075 vfs_unbusy(mp); 2076 if (*rvp != vp) 2077 vn_lock(vp, ltype | LK_RETRY); 2078 if (vp->v_iflag & VI_DOOMED) { 2079 if (error == 0) { 2080 if (*rvp == vp) 2081 vunref(vp); 2082 else 2083 vput(*rvp); 2084 } 2085 error = ENOENT; 2086 } 2087 return (error); 2088} 2089 2090int 2091vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2092 struct thread *td) 2093{ 2094 2095 if (vp->v_type != VREG || td == NULL) 2096 return (0); 2097 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2098 lim_cur(td, RLIMIT_FSIZE)) { 2099 PROC_LOCK(td->td_proc); 2100 kern_psignal(td->td_proc, SIGXFSZ); 2101 PROC_UNLOCK(td->td_proc); 2102 return (EFBIG); 2103 } 2104 return (0); 2105} 2106 2107int 2108vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2109 struct thread *td) 2110{ 2111 struct vnode *vp; 2112 2113 vp = fp->f_vnode; 2114#ifdef AUDIT 2115 vn_lock(vp, LK_SHARED | LK_RETRY); 2116 AUDIT_ARG_VNODE1(vp); 2117 VOP_UNLOCK(vp, 0); 2118#endif 2119 return (setfmode(td, active_cred, vp, mode)); 2120} 2121 2122int 2123vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2124 struct thread *td) 2125{ 2126 struct vnode *vp; 2127 2128 vp = fp->f_vnode; 2129#ifdef AUDIT 2130 vn_lock(vp, LK_SHARED | LK_RETRY); 2131 AUDIT_ARG_VNODE1(vp); 2132 VOP_UNLOCK(vp, 0); 2133#endif 2134 return (setfown(td, active_cred, vp, uid, gid)); 2135} 2136 2137void 2138vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2139{ 2140 vm_object_t object; 2141 2142 if ((object = vp->v_object) == NULL) 2143 return; 2144 VM_OBJECT_WLOCK(object); 2145 vm_object_page_remove(object, start, end, 0); 2146 VM_OBJECT_WUNLOCK(object); 2147} 2148 2149int 2150vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2151{ 2152 struct vattr va; 2153 daddr_t bn, bnp; 2154 uint64_t bsize; 2155 off_t noff; 2156 int error; 2157 2158 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2159 ("Wrong command %lu", cmd)); 2160 2161 if (vn_lock(vp, LK_SHARED) != 0) 2162 return (EBADF); 2163 if (vp->v_type != VREG) { 2164 error = ENOTTY; 2165 goto unlock; 2166 } 2167 error = VOP_GETATTR(vp, &va, cred); 2168 if (error != 0) 2169 goto unlock; 2170 noff = *off; 2171 if (noff >= va.va_size) { 2172 error = ENXIO; 2173 goto unlock; 2174 } 2175 bsize = vp->v_mount->mnt_stat.f_iosize; 2176 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) { 2177 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2178 if (error == EOPNOTSUPP) { 2179 error = ENOTTY; 2180 goto unlock; 2181 } 2182 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2183 (bnp != -1 && cmd == FIOSEEKDATA)) { 2184 noff = bn * bsize; 2185 if (noff < *off) 2186 noff = *off; 2187 goto unlock; 2188 } 2189 } 2190 if (noff > va.va_size) 2191 noff = va.va_size; 2192 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2193 if (cmd == FIOSEEKDATA) 2194 error = ENXIO; 2195unlock: 2196 VOP_UNLOCK(vp, 0); 2197 if (error == 0) 2198 *off = noff; 2199 return (error); 2200} 2201 2202int 2203vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2204{ 2205 struct ucred *cred; 2206 struct vnode *vp; 2207 struct vattr vattr; 2208 off_t foffset, size; 2209 int error, noneg; 2210 2211 cred = td->td_ucred; 2212 vp = fp->f_vnode; 2213 foffset = foffset_lock(fp, 0); 2214 noneg = (vp->v_type != VCHR); 2215 error = 0; 2216 switch (whence) { 2217 case L_INCR: 2218 if (noneg && 2219 (foffset < 0 || 2220 (offset > 0 && foffset > OFF_MAX - offset))) { 2221 error = EOVERFLOW; 2222 break; 2223 } 2224 offset += foffset; 2225 break; 2226 case L_XTND: 2227 vn_lock(vp, LK_SHARED | LK_RETRY); 2228 error = VOP_GETATTR(vp, &vattr, cred); 2229 VOP_UNLOCK(vp, 0); 2230 if (error) 2231 break; 2232 2233 /* 2234 * If the file references a disk device, then fetch 2235 * the media size and use that to determine the ending 2236 * offset. 2237 */ 2238 if (vattr.va_size == 0 && vp->v_type == VCHR && 2239 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2240 vattr.va_size = size; 2241 if (noneg && 2242 (vattr.va_size > OFF_MAX || 2243 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2244 error = EOVERFLOW; 2245 break; 2246 } 2247 offset += vattr.va_size; 2248 break; 2249 case L_SET: 2250 break; 2251 case SEEK_DATA: 2252 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2253 break; 2254 case SEEK_HOLE: 2255 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2256 break; 2257 default: 2258 error = EINVAL; 2259 } 2260 if (error == 0 && noneg && offset < 0) 2261 error = EINVAL; 2262 if (error != 0) 2263 goto drop; 2264 VFS_KNOTE_UNLOCKED(vp, 0); 2265 td->td_uretoff.tdu_off = offset; 2266drop: 2267 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2268 return (error); 2269} 2270 2271int 2272vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2273 struct thread *td) 2274{ 2275 int error; 2276 2277 /* 2278 * Grant permission if the caller is the owner of the file, or 2279 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2280 * on the file. If the time pointer is null, then write 2281 * permission on the file is also sufficient. 2282 * 2283 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2284 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2285 * will be allowed to set the times [..] to the current 2286 * server time. 2287 */ 2288 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2289 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2290 error = VOP_ACCESS(vp, VWRITE, cred, td); 2291 return (error); 2292} 2293 2294int 2295vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2296{ 2297 struct vnode *vp; 2298 int error; 2299 2300 if (fp->f_type == DTYPE_FIFO) 2301 kif->kf_type = KF_TYPE_FIFO; 2302 else 2303 kif->kf_type = KF_TYPE_VNODE; 2304 vp = fp->f_vnode; 2305 vref(vp); 2306 FILEDESC_SUNLOCK(fdp); 2307 error = vn_fill_kinfo_vnode(vp, kif); 2308 vrele(vp); 2309 FILEDESC_SLOCK(fdp); 2310 return (error); 2311} 2312 2313static inline void 2314vn_fill_junk(struct kinfo_file *kif) 2315{ 2316 size_t len, olen; 2317 2318 /* 2319 * Simulate vn_fullpath returning changing values for a given 2320 * vp during e.g. coredump. 2321 */ 2322 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2323 olen = strlen(kif->kf_path); 2324 if (len < olen) 2325 strcpy(&kif->kf_path[len - 1], "$"); 2326 else 2327 for (; olen < len; olen++) 2328 strcpy(&kif->kf_path[olen], "A"); 2329} 2330 2331int 2332vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2333{ 2334 struct vattr va; 2335 char *fullpath, *freepath; 2336 int error; 2337 2338 kif->kf_vnode_type = vntype_to_kinfo(vp->v_type); 2339 freepath = NULL; 2340 fullpath = "-"; 2341 error = vn_fullpath(curthread, vp, &fullpath, &freepath); 2342 if (error == 0) { 2343 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2344 } 2345 if (freepath != NULL) 2346 free(freepath, M_TEMP); 2347 2348 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2349 vn_fill_junk(kif); 2350 ); 2351 2352 /* 2353 * Retrieve vnode attributes. 2354 */ 2355 va.va_fsid = VNOVAL; 2356 va.va_rdev = NODEV; 2357 vn_lock(vp, LK_SHARED | LK_RETRY); 2358 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2359 VOP_UNLOCK(vp, 0); 2360 if (error != 0) 2361 return (error); 2362 if (va.va_fsid != VNOVAL) 2363 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2364 else 2365 kif->kf_un.kf_file.kf_file_fsid = 2366 vp->v_mount->mnt_stat.f_fsid.val[0]; 2367 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2368 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2369 kif->kf_un.kf_file.kf_file_size = va.va_size; 2370 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2371 return (0); 2372} 2373 2374int 2375vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2376 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2377 struct thread *td) 2378{ 2379#ifdef HWPMC_HOOKS 2380 struct pmckern_map_in pkm; 2381#endif 2382 struct mount *mp; 2383 struct vnode *vp; 2384 vm_object_t object; 2385 vm_prot_t maxprot; 2386 boolean_t writecounted; 2387 int error; 2388 2389#if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2390 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2391 /* 2392 * POSIX shared-memory objects are defined to have 2393 * kernel persistence, and are not defined to support 2394 * read(2)/write(2) -- or even open(2). Thus, we can 2395 * use MAP_ASYNC to trade on-disk coherence for speed. 2396 * The shm_open(3) library routine turns on the FPOSIXSHM 2397 * flag to request this behavior. 2398 */ 2399 if ((fp->f_flag & FPOSIXSHM) != 0) 2400 flags |= MAP_NOSYNC; 2401#endif 2402 vp = fp->f_vnode; 2403 2404 /* 2405 * Ensure that file and memory protections are 2406 * compatible. Note that we only worry about 2407 * writability if mapping is shared; in this case, 2408 * current and max prot are dictated by the open file. 2409 * XXX use the vnode instead? Problem is: what 2410 * credentials do we use for determination? What if 2411 * proc does a setuid? 2412 */ 2413 mp = vp->v_mount; 2414 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2415 maxprot = VM_PROT_NONE; 2416 if ((prot & VM_PROT_EXECUTE) != 0) 2417 return (EACCES); 2418 } else 2419 maxprot = VM_PROT_EXECUTE; 2420 if ((fp->f_flag & FREAD) != 0) 2421 maxprot |= VM_PROT_READ; 2422 else if ((prot & VM_PROT_READ) != 0) 2423 return (EACCES); 2424 2425 /* 2426 * If we are sharing potential changes via MAP_SHARED and we 2427 * are trying to get write permission although we opened it 2428 * without asking for it, bail out. 2429 */ 2430 if ((flags & MAP_SHARED) != 0) { 2431 if ((fp->f_flag & FWRITE) != 0) 2432 maxprot |= VM_PROT_WRITE; 2433 else if ((prot & VM_PROT_WRITE) != 0) 2434 return (EACCES); 2435 } else { 2436 maxprot |= VM_PROT_WRITE; 2437 cap_maxprot |= VM_PROT_WRITE; 2438 } 2439 maxprot &= cap_maxprot; 2440 2441 /* 2442 * For regular files and shared memory, POSIX requires that 2443 * the value of foff be a legitimate offset within the data 2444 * object. In particular, negative offsets are invalid. 2445 * Blocking negative offsets and overflows here avoids 2446 * possible wraparound or user-level access into reserved 2447 * ranges of the data object later. In contrast, POSIX does 2448 * not dictate how offsets are used by device drivers, so in 2449 * the case of a device mapping a negative offset is passed 2450 * on. 2451 */ 2452 if ( 2453#ifdef _LP64 2454 size > OFF_MAX || 2455#endif 2456 foff < 0 || foff > OFF_MAX - size) 2457 return (EINVAL); 2458 2459 writecounted = FALSE; 2460 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2461 &foff, &object, &writecounted); 2462 if (error != 0) 2463 return (error); 2464 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2465 foff, writecounted, td); 2466 if (error != 0) { 2467 /* 2468 * If this mapping was accounted for in the vnode's 2469 * writecount, then undo that now. 2470 */ 2471 if (writecounted) 2472 vnode_pager_release_writecount(object, 0, size); 2473 vm_object_deallocate(object); 2474 } 2475#ifdef HWPMC_HOOKS 2476 /* Inform hwpmc(4) if an executable is being mapped. */ 2477 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2478 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2479 pkm.pm_file = vp; 2480 pkm.pm_address = (uintptr_t) *addr; 2481 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm); 2482 } 2483 } 2484#endif 2485 return (error); 2486} 2487