vfs_vnops.c revision 1.41
1 /* $NetBSD: vfs_vnops.c,v 1.41 2000/03/30 09:27:15 augustss Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 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 8.14 (Berkeley) 6/15/95 41 */ 42 43 #include "fs_union.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/file.h> 49 #include <sys/stat.h> 50 #include <sys/buf.h> 51 #include <sys/proc.h> 52 #include <sys/mount.h> 53 #include <sys/namei.h> 54 #include <sys/vnode.h> 55 #include <sys/ioctl.h> 56 #include <sys/tty.h> 57 #include <sys/poll.h> 58 59 #include <vm/vm.h> 60 61 #include <uvm/uvm_extern.h> 62 63 #ifdef UNION 64 #include <miscfs/union/union.h> 65 #endif 66 67 struct fileops vnops = 68 { vn_read, vn_write, vn_ioctl, vn_fcntl, vn_poll, vn_closefile }; 69 70 /* 71 * Common code for vnode open operations. 72 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 73 */ 74 int 75 vn_open(ndp, fmode, cmode) 76 struct nameidata *ndp; 77 int fmode, cmode; 78 { 79 struct vnode *vp; 80 struct proc *p = ndp->ni_cnd.cn_proc; 81 struct ucred *cred = p->p_ucred; 82 struct vattr va; 83 int error; 84 85 if (fmode & O_CREAT) { 86 ndp->ni_cnd.cn_nameiop = CREATE; 87 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 88 if ((fmode & O_EXCL) == 0 && 89 ((fmode & FNOSYMLINK) == 0)) 90 ndp->ni_cnd.cn_flags |= FOLLOW; 91 if ((error = namei(ndp)) != 0) 92 return (error); 93 if (ndp->ni_vp == NULL) { 94 VATTR_NULL(&va); 95 va.va_type = VREG; 96 va.va_mode = cmode; 97 if (fmode & O_EXCL) 98 va.va_vaflags |= VA_EXCLUSIVE; 99 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 100 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 101 &ndp->ni_cnd, &va); 102 if (error) 103 return (error); 104 fmode &= ~O_TRUNC; 105 vp = ndp->ni_vp; 106 } else { 107 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 108 if (ndp->ni_dvp == ndp->ni_vp) 109 vrele(ndp->ni_dvp); 110 else 111 vput(ndp->ni_dvp); 112 ndp->ni_dvp = NULL; 113 vp = ndp->ni_vp; 114 if (fmode & O_EXCL) { 115 error = EEXIST; 116 goto bad; 117 } 118 if (ndp->ni_vp->v_type == VLNK) { 119 error = EFTYPE; 120 goto bad; 121 } 122 fmode &= ~O_CREAT; 123 } 124 } else { 125 ndp->ni_cnd.cn_nameiop = LOOKUP; 126 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF; 127 if ((error = namei(ndp)) != 0) 128 return (error); 129 vp = ndp->ni_vp; 130 } 131 if (vp->v_type == VSOCK) { 132 error = EOPNOTSUPP; 133 goto bad; 134 } 135 if ((fmode & O_CREAT) == 0) { 136 if (fmode & FREAD) { 137 if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) 138 goto bad; 139 } 140 if (fmode & (FWRITE | O_TRUNC)) { 141 if (vp->v_type == VDIR) { 142 error = EISDIR; 143 goto bad; 144 } 145 if ((error = vn_writechk(vp)) != 0 || 146 (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) 147 goto bad; 148 } 149 } 150 if (fmode & O_TRUNC) { 151 VOP_UNLOCK(vp, 0); /* XXX */ 152 VOP_LEASE(vp, p, cred, LEASE_WRITE); 153 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); /* XXX */ 154 VATTR_NULL(&va); 155 va.va_size = 0; 156 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 157 goto bad; 158 } 159 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 160 goto bad; 161 if (fmode & FWRITE) 162 vp->v_writecount++; 163 return (0); 164 bad: 165 vput(vp); 166 return (error); 167 } 168 169 /* 170 * Check for write permissions on the specified vnode. 171 * Prototype text segments cannot be written. 172 */ 173 int 174 vn_writechk(vp) 175 struct vnode *vp; 176 { 177 178 /* 179 * If there's shared text associated with 180 * the vnode, try to free it up once. If 181 * we fail, we can't allow writing. 182 */ 183 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 184 return (ETXTBSY); 185 return (0); 186 } 187 188 /* 189 * Vnode close call 190 * 191 * Note: takes an unlocked vnode, while VOP_CLOSE takes a locked node. 192 */ 193 int 194 vn_close(vp, flags, cred, p) 195 struct vnode *vp; 196 int flags; 197 struct ucred *cred; 198 struct proc *p; 199 { 200 int error; 201 202 if (flags & FWRITE) 203 vp->v_writecount--; 204 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 205 error = VOP_CLOSE(vp, flags, cred, p); 206 vput(vp); 207 return (error); 208 } 209 210 /* 211 * Package up an I/O request on a vnode into a uio and do it. 212 */ 213 int 214 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 215 enum uio_rw rw; 216 struct vnode *vp; 217 caddr_t base; 218 int len; 219 off_t offset; 220 enum uio_seg segflg; 221 int ioflg; 222 struct ucred *cred; 223 size_t *aresid; 224 struct proc *p; 225 { 226 struct uio auio; 227 struct iovec aiov; 228 int error; 229 230 if ((ioflg & IO_NODELOCKED) == 0) 231 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 232 auio.uio_iov = &aiov; 233 auio.uio_iovcnt = 1; 234 aiov.iov_base = base; 235 aiov.iov_len = len; 236 auio.uio_resid = len; 237 auio.uio_offset = offset; 238 auio.uio_segflg = segflg; 239 auio.uio_rw = rw; 240 auio.uio_procp = p; 241 if (rw == UIO_READ) { 242 error = VOP_READ(vp, &auio, ioflg, cred); 243 } else { 244 error = VOP_WRITE(vp, &auio, ioflg, cred); 245 } 246 if (aresid) 247 *aresid = auio.uio_resid; 248 else 249 if (auio.uio_resid && error == 0) 250 error = EIO; 251 if ((ioflg & IO_NODELOCKED) == 0) 252 VOP_UNLOCK(vp, 0); 253 return (error); 254 } 255 256 int 257 vn_readdir(fp, buf, segflg, count, done, p, cookies, ncookies) 258 struct file *fp; 259 char *buf; 260 int segflg, *done, *ncookies; 261 u_int count; 262 struct proc *p; 263 off_t **cookies; 264 { 265 struct vnode *vp = (struct vnode *)fp->f_data; 266 struct iovec aiov; 267 struct uio auio; 268 int error, eofflag; 269 270 unionread: 271 if (vp->v_type != VDIR) 272 return (EINVAL); 273 aiov.iov_base = buf; 274 aiov.iov_len = count; 275 auio.uio_iov = &aiov; 276 auio.uio_iovcnt = 1; 277 auio.uio_rw = UIO_READ; 278 auio.uio_segflg = segflg; 279 auio.uio_procp = p; 280 auio.uio_resid = count; 281 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 282 auio.uio_offset = fp->f_offset; 283 error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, cookies, 284 ncookies); 285 fp->f_offset = auio.uio_offset; 286 VOP_UNLOCK(vp, 0); 287 if (error) 288 return (error); 289 290 #ifdef UNION 291 { 292 extern struct vnode *union_dircache __P((struct vnode *)); 293 294 if (count == auio.uio_resid && (vp->v_op == union_vnodeop_p)) { 295 struct vnode *lvp; 296 297 lvp = union_dircache(vp); 298 if (lvp != NULLVP) { 299 struct vattr va; 300 301 /* 302 * If the directory is opaque, 303 * then don't show lower entries 304 */ 305 error = VOP_GETATTR(vp, &va, fp->f_cred, p); 306 if (va.va_flags & OPAQUE) { 307 vput(lvp); 308 lvp = NULL; 309 } 310 } 311 312 if (lvp != NULLVP) { 313 error = VOP_OPEN(lvp, FREAD, fp->f_cred, p); 314 if (error) { 315 vput(lvp); 316 return (error); 317 } 318 VOP_UNLOCK(lvp, 0); 319 fp->f_data = (caddr_t) lvp; 320 fp->f_offset = 0; 321 error = vn_close(vp, FREAD, fp->f_cred, p); 322 if (error) 323 return (error); 324 vp = lvp; 325 goto unionread; 326 } 327 } 328 } 329 #endif /* UNION */ 330 331 if (count == auio.uio_resid && (vp->v_flag & VROOT) && 332 (vp->v_mount->mnt_flag & MNT_UNION)) { 333 struct vnode *tvp = vp; 334 vp = vp->v_mount->mnt_vnodecovered; 335 VREF(vp); 336 fp->f_data = (caddr_t) vp; 337 fp->f_offset = 0; 338 vrele(tvp); 339 goto unionread; 340 } 341 *done = count - auio.uio_resid; 342 return error; 343 } 344 345 /* 346 * File table vnode read routine. 347 */ 348 int 349 vn_read(fp, offset, uio, cred, flags) 350 struct file *fp; 351 off_t *offset; 352 struct uio *uio; 353 struct ucred *cred; 354 int flags; 355 { 356 struct vnode *vp = (struct vnode *)fp->f_data; 357 int count, error, ioflag = 0; 358 359 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_READ); 360 if (fp->f_flag & FNONBLOCK) 361 ioflag |= IO_NDELAY; 362 if ((fp->f_flag & (FFSYNC | FRSYNC)) == (FFSYNC | FRSYNC)) 363 ioflag |= IO_SYNC; 364 if (fp->f_flag & FALTIO) 365 ioflag |= IO_ALTSEMANTICS; 366 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 367 uio->uio_offset = *offset; 368 count = uio->uio_resid; 369 error = VOP_READ(vp, uio, ioflag, cred); 370 if (flags & FOF_UPDATE_OFFSET) 371 *offset += count - uio->uio_resid; 372 VOP_UNLOCK(vp, 0); 373 return (error); 374 } 375 376 /* 377 * File table vnode write routine. 378 */ 379 int 380 vn_write(fp, offset, uio, cred, flags) 381 struct file *fp; 382 off_t *offset; 383 struct uio *uio; 384 struct ucred *cred; 385 int flags; 386 { 387 struct vnode *vp = (struct vnode *)fp->f_data; 388 int count, error, ioflag = IO_UNIT; 389 390 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 391 ioflag |= IO_APPEND; 392 if (fp->f_flag & FNONBLOCK) 393 ioflag |= IO_NDELAY; 394 if (fp->f_flag & FFSYNC || 395 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 396 ioflag |= IO_SYNC; 397 else if (fp->f_flag & FDSYNC) 398 ioflag |= IO_DSYNC; 399 if (fp->f_flag & FALTIO) 400 ioflag |= IO_ALTSEMANTICS; 401 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE); 402 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 403 uio->uio_offset = *offset; 404 count = uio->uio_resid; 405 error = VOP_WRITE(vp, uio, ioflag, cred); 406 if (flags & FOF_UPDATE_OFFSET) { 407 if (ioflag & IO_APPEND) 408 *offset = uio->uio_offset; 409 else 410 *offset += count - uio->uio_resid; 411 } 412 VOP_UNLOCK(vp, 0); 413 return (error); 414 } 415 416 /* 417 * File table vnode stat routine. 418 */ 419 int 420 vn_stat(vp, sb, p) 421 struct vnode *vp; 422 struct stat *sb; 423 struct proc *p; 424 { 425 struct vattr va; 426 int error; 427 mode_t mode; 428 429 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 430 if (error) 431 return (error); 432 /* 433 * Copy from vattr table 434 */ 435 sb->st_dev = va.va_fsid; 436 sb->st_ino = va.va_fileid; 437 mode = va.va_mode; 438 switch (vp->v_type) { 439 case VREG: 440 mode |= S_IFREG; 441 break; 442 case VDIR: 443 mode |= S_IFDIR; 444 break; 445 case VBLK: 446 mode |= S_IFBLK; 447 break; 448 case VCHR: 449 mode |= S_IFCHR; 450 break; 451 case VLNK: 452 mode |= S_IFLNK; 453 break; 454 case VSOCK: 455 mode |= S_IFSOCK; 456 break; 457 case VFIFO: 458 mode |= S_IFIFO; 459 break; 460 default: 461 return (EBADF); 462 }; 463 sb->st_mode = mode; 464 sb->st_nlink = va.va_nlink; 465 sb->st_uid = va.va_uid; 466 sb->st_gid = va.va_gid; 467 sb->st_rdev = va.va_rdev; 468 sb->st_size = va.va_size; 469 sb->st_atimespec = va.va_atime; 470 sb->st_mtimespec = va.va_mtime; 471 sb->st_ctimespec = va.va_ctime; 472 sb->st_blksize = va.va_blocksize; 473 sb->st_flags = va.va_flags; 474 sb->st_gen = 0; 475 sb->st_blocks = va.va_bytes / S_BLKSIZE; 476 return (0); 477 } 478 479 /* 480 * File table vnode fcntl routine. 481 */ 482 int 483 vn_fcntl(fp, com, data, p) 484 struct file *fp; 485 u_int com; 486 caddr_t data; 487 struct proc *p; 488 { 489 struct vnode *vp = ((struct vnode *)fp->f_data); 490 int error; 491 492 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 493 error = VOP_FCNTL(vp, com, data, fp->f_flag, p->p_ucred, p); 494 VOP_UNLOCK(vp, 0); 495 return (error); 496 } 497 498 /* 499 * File table vnode ioctl routine. 500 */ 501 int 502 vn_ioctl(fp, com, data, p) 503 struct file *fp; 504 u_long com; 505 caddr_t data; 506 struct proc *p; 507 { 508 struct vnode *vp = ((struct vnode *)fp->f_data); 509 struct vattr vattr; 510 int error; 511 512 switch (vp->v_type) { 513 514 case VREG: 515 case VDIR: 516 if (com == FIONREAD) { 517 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 518 if (error) 519 return (error); 520 *(int *)data = vattr.va_size - fp->f_offset; 521 return (0); 522 } 523 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 524 return (0); /* XXX */ 525 /* fall into ... */ 526 527 default: 528 return (ENOTTY); 529 530 case VFIFO: 531 case VCHR: 532 case VBLK: 533 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 534 if (error == 0 && com == TIOCSCTTY) { 535 if (p->p_session->s_ttyvp) 536 vrele(p->p_session->s_ttyvp); 537 p->p_session->s_ttyvp = vp; 538 VREF(vp); 539 } 540 return (error); 541 } 542 } 543 544 /* 545 * File table vnode poll routine. 546 */ 547 int 548 vn_poll(fp, events, p) 549 struct file *fp; 550 int events; 551 struct proc *p; 552 { 553 554 return (VOP_POLL(((struct vnode *)fp->f_data), events, p)); 555 } 556 557 /* 558 * Check that the vnode is still valid, and if so 559 * acquire requested lock. 560 */ 561 int 562 vn_lock(vp, flags) 563 struct vnode *vp; 564 int flags; 565 { 566 int error; 567 568 do { 569 if ((flags & LK_INTERLOCK) == 0) 570 simple_lock(&vp->v_interlock); 571 if (vp->v_flag & VXLOCK) { 572 vp->v_flag |= VXWANT; 573 simple_unlock(&vp->v_interlock); 574 tsleep((caddr_t)vp, PINOD, "vn_lock", 0); 575 error = ENOENT; 576 } else { 577 error = VOP_LOCK(vp, flags | LK_INTERLOCK); 578 if (error == 0 || error == EDEADLK) 579 return (error); 580 } 581 flags &= ~LK_INTERLOCK; 582 } while (flags & LK_RETRY); 583 return (error); 584 } 585 586 /* 587 * File table vnode close routine. 588 */ 589 int 590 vn_closefile(fp, p) 591 struct file *fp; 592 struct proc *p; 593 { 594 595 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 596 fp->f_cred, p)); 597 } 598 599 /* 600 * Enable LK_CANRECURSE on lock. Return prior status. 601 */ 602 u_int 603 vn_setrecurse(vp) 604 struct vnode *vp; 605 { 606 struct lock *lkp = &vp->v_lock; 607 u_int retval = lkp->lk_flags & LK_CANRECURSE; 608 609 lkp->lk_flags |= LK_CANRECURSE; 610 return retval; 611 } 612 613 /* 614 * Called when done with locksetrecurse. 615 */ 616 void 617 vn_restorerecurse(vp, flags) 618 struct vnode *vp; 619 u_int flags; 620 { 621 struct lock *lkp = &vp->v_lock; 622 623 lkp->lk_flags &= ~LK_CANRECURSE; 624 lkp->lk_flags |= flags; 625 } 626
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