1 /* $OpenBSD: vfs_vnops.c,v 1.71 2012/07/11 12:39:20 guenther Exp $ */ 2 /* $NetBSD: vfs_vnops.c,v 1.20 1996/02/04 02:18:41 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)vfs_vnops.c 8.5 (Berkeley) 12/8/94 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/file.h> 45 #include <sys/stat.h> 46 #include <sys/buf.h> 47 #include <sys/proc.h> 48 #include <sys/resourcevar.h> 49 #include <sys/signalvar.h> 50 #include <sys/mount.h> 51 #include <sys/namei.h> 52 #include <sys/vnode.h> 53 #include <sys/ioctl.h> 54 #include <sys/tty.h> 55 #include <sys/cdio.h> 56 #include <sys/poll.h> 57 #include <sys/filedesc.h> 58 #include <sys/specdev.h> 59 60 #include <uvm/uvm_extern.h> 61 62 int vn_read(struct file *, off_t *, struct uio *, struct ucred *); 63 int vn_write(struct file *, off_t *, struct uio *, struct ucred *); 64 int vn_poll(struct file *, int, struct proc *); 65 int vn_kqfilter(struct file *, struct knote *); 66 int vn_closefile(struct file *, struct proc *); 67 68 struct fileops vnops = 69 { vn_read, vn_write, vn_ioctl, vn_poll, vn_kqfilter, vn_statfile, 70 vn_closefile }; 71 72 /* 73 * Common code for vnode open operations. 74 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 75 */ 76 int 77 vn_open(struct nameidata *ndp, int fmode, int 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 struct cloneinfo *cip; 84 int error; 85 86 if ((fmode & (FREAD|FWRITE)) == 0) 87 return (EINVAL); 88 if ((fmode & (O_TRUNC | FWRITE)) == O_TRUNC) 89 return (EINVAL); 90 if (fmode & O_CREAT) { 91 ndp->ni_cnd.cn_nameiop = CREATE; 92 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 93 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 94 ndp->ni_cnd.cn_flags |= FOLLOW; 95 if ((error = namei(ndp)) != 0) 96 return (error); 97 98 if (ndp->ni_vp == NULL) { 99 VATTR_NULL(&va); 100 va.va_type = VREG; 101 va.va_mode = cmode; 102 if (fmode & O_EXCL) 103 va.va_vaflags |= VA_EXCLUSIVE; 104 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 105 &ndp->ni_cnd, &va); 106 if (error) 107 return (error); 108 fmode &= ~O_TRUNC; 109 vp = ndp->ni_vp; 110 } else { 111 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 112 if (ndp->ni_dvp == ndp->ni_vp) 113 vrele(ndp->ni_dvp); 114 else 115 vput(ndp->ni_dvp); 116 ndp->ni_dvp = NULL; 117 vp = ndp->ni_vp; 118 if (fmode & O_EXCL) { 119 error = EEXIST; 120 goto bad; 121 } 122 fmode &= ~O_CREAT; 123 } 124 } else { 125 ndp->ni_cnd.cn_nameiop = LOOKUP; 126 ndp->ni_cnd.cn_flags = 127 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 128 if ((error = namei(ndp)) != 0) 129 return (error); 130 vp = ndp->ni_vp; 131 } 132 if (vp->v_type == VSOCK) { 133 error = EOPNOTSUPP; 134 goto bad; 135 } 136 if (vp->v_type == VLNK) { 137 error = ELOOP; 138 goto bad; 139 } 140 if ((fmode & O_DIRECTORY) && vp->v_type != VDIR) { 141 error = ENOTDIR; 142 goto bad; 143 } 144 if ((fmode & O_CREAT) == 0) { 145 if (fmode & FREAD) { 146 if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) 147 goto bad; 148 } 149 if (fmode & FWRITE) { 150 if (vp->v_type == VDIR) { 151 error = EISDIR; 152 goto bad; 153 } 154 if ((error = vn_writechk(vp)) != 0 || 155 (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) 156 goto bad; 157 } 158 } 159 if ((fmode & O_TRUNC) && vp->v_type == VREG) { 160 VATTR_NULL(&va); 161 va.va_size = 0; 162 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 163 goto bad; 164 } 165 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 166 goto bad; 167 168 if (vp->v_flag & VCLONED) { 169 cip = (struct cloneinfo *)vp->v_data; 170 171 vp->v_flag &= ~VCLONED; 172 173 ndp->ni_vp = cip->ci_vp; /* return cloned vnode */ 174 vp->v_data = cip->ci_data; /* restore v_data */ 175 VOP_UNLOCK(vp, 0, p); /* keep a reference */ 176 vp = ndp->ni_vp; /* for the increment below */ 177 178 free(cip, M_TEMP); 179 } 180 181 if (fmode & FWRITE) 182 vp->v_writecount++; 183 return (0); 184 bad: 185 vput(vp); 186 return (error); 187 } 188 189 /* 190 * Check for write permissions on the specified vnode. 191 * Prototype text segments cannot be written. 192 */ 193 int 194 vn_writechk(struct vnode *vp) 195 { 196 /* 197 * Disallow write attempts on read-only file systems; 198 * unless the file is a socket or a block or character 199 * device resident on the file system. 200 */ 201 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 202 switch (vp->v_type) { 203 case VREG: 204 case VDIR: 205 case VLNK: 206 return (EROFS); 207 case VNON: 208 case VCHR: 209 case VSOCK: 210 case VFIFO: 211 case VBAD: 212 case VBLK: 213 break; 214 } 215 } 216 /* 217 * If there's shared text associated with 218 * the vnode, try to free it up once. If 219 * we fail, we can't allow writing. 220 */ 221 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 222 return (ETXTBSY); 223 224 return (0); 225 } 226 227 /* 228 * Check whether a write operation would exceed the file size rlimit 229 * for the process, if one should be applied for this operation. 230 * If a partial write should take place, the uio is adjusted and the 231 * amount by which the request would have exceeded the limit is returned 232 * via the 'overrun' argument. 233 */ 234 int 235 vn_fsizechk(struct vnode *vp, struct uio *uio, int ioflag, int *overrun) 236 { 237 struct proc *p = uio->uio_procp; 238 239 *overrun = 0; 240 if (vp->v_type == VREG && p != NULL && !(ioflag & IO_NOLIMIT)) { 241 rlim_t limit = p->p_rlimit[RLIMIT_FSIZE].rlim_cur; 242 243 /* if already at or over the limit, send the signal and fail */ 244 if (uio->uio_offset >= limit) { 245 psignal(p, SIGXFSZ); 246 return (EFBIG); 247 } 248 249 /* otherwise, clamp the write to stay under the limit */ 250 if (uio->uio_resid > limit - uio->uio_offset) { 251 *overrun = uio->uio_resid - (limit - uio->uio_offset); 252 uio->uio_resid = limit - uio->uio_offset; 253 } 254 } 255 256 return (0); 257 } 258 259 260 /* 261 * Mark a vnode as being the text image of a running process. 262 */ 263 void 264 vn_marktext(struct vnode *vp) 265 { 266 vp->v_flag |= VTEXT; 267 } 268 269 /* 270 * Vnode close call 271 */ 272 int 273 vn_close(struct vnode *vp, int flags, struct ucred *cred, struct proc *p) 274 { 275 int error; 276 277 if (flags & FWRITE) 278 vp->v_writecount--; 279 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 280 error = VOP_CLOSE(vp, flags, cred, p); 281 vput(vp); 282 return (error); 283 } 284 285 /* 286 * Package up an I/O request on a vnode into a uio and do it. 287 */ 288 int 289 vn_rdwr(enum uio_rw rw, struct vnode *vp, caddr_t base, int len, off_t offset, 290 enum uio_seg segflg, int ioflg, struct ucred *cred, size_t *aresid, 291 struct proc *p) 292 { 293 struct uio auio; 294 struct iovec aiov; 295 int error; 296 297 auio.uio_iov = &aiov; 298 auio.uio_iovcnt = 1; 299 aiov.iov_base = base; 300 aiov.iov_len = len; 301 auio.uio_resid = len; 302 auio.uio_offset = offset; 303 auio.uio_segflg = segflg; 304 auio.uio_rw = rw; 305 auio.uio_procp = p; 306 307 if ((ioflg & IO_NODELOCKED) == 0) 308 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 309 if (rw == UIO_READ) { 310 error = VOP_READ(vp, &auio, ioflg, cred); 311 } else { 312 error = VOP_WRITE(vp, &auio, ioflg, cred); 313 } 314 if ((ioflg & IO_NODELOCKED) == 0) 315 VOP_UNLOCK(vp, 0, p); 316 317 if (aresid) 318 *aresid = auio.uio_resid; 319 else 320 if (auio.uio_resid && error == 0) 321 error = EIO; 322 return (error); 323 } 324 325 /* 326 * File table vnode read routine. 327 */ 328 int 329 vn_read(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred) 330 { 331 struct vnode *vp = (struct vnode *)fp->f_data; 332 int error = 0; 333 size_t count = uio->uio_resid; 334 struct proc *p = uio->uio_procp; 335 336 /* no wrap around of offsets except on character devices */ 337 if (vp->v_type != VCHR && count > LLONG_MAX - *poff) 338 return (EINVAL); 339 340 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 341 uio->uio_offset = *poff; 342 if (vp->v_type != VDIR) 343 error = VOP_READ(vp, uio, 344 (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, cred); 345 *poff += count - uio->uio_resid; 346 VOP_UNLOCK(vp, 0, p); 347 return (error); 348 } 349 350 /* 351 * File table vnode write routine. 352 */ 353 int 354 vn_write(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred) 355 { 356 struct vnode *vp = (struct vnode *)fp->f_data; 357 struct proc *p = uio->uio_procp; 358 int error, ioflag = IO_UNIT; 359 size_t count; 360 361 /* note: pwrite/pwritev are unaffected by O_APPEND */ 362 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) && 363 poff == &fp->f_offset) 364 ioflag |= IO_APPEND; 365 if (fp->f_flag & FNONBLOCK) 366 ioflag |= IO_NDELAY; 367 if ((fp->f_flag & FFSYNC) || 368 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 369 ioflag |= IO_SYNC; 370 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 371 uio->uio_offset = *poff; 372 count = uio->uio_resid; 373 error = VOP_WRITE(vp, uio, ioflag, cred); 374 if (ioflag & IO_APPEND) 375 *poff = uio->uio_offset; 376 else 377 *poff += count - uio->uio_resid; 378 VOP_UNLOCK(vp, 0, p); 379 return (error); 380 } 381 382 /* 383 * File table wrapper for vn_stat 384 */ 385 int 386 vn_statfile(struct file *fp, struct stat *sb, struct proc *p) 387 { 388 struct vnode *vp = (struct vnode *)fp->f_data; 389 return vn_stat(vp, sb, p); 390 } 391 392 /* 393 * vnode stat routine. 394 */ 395 int 396 vn_stat(struct vnode *vp, struct stat *sb, struct proc *p) 397 { 398 struct vattr va; 399 int error; 400 mode_t mode; 401 402 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 403 if (error) 404 return (error); 405 /* 406 * Copy from vattr table 407 */ 408 sb->st_dev = va.va_fsid; 409 sb->st_ino = va.va_fileid; 410 mode = va.va_mode; 411 switch (vp->v_type) { 412 case VREG: 413 mode |= S_IFREG; 414 break; 415 case VDIR: 416 mode |= S_IFDIR; 417 break; 418 case VBLK: 419 mode |= S_IFBLK; 420 break; 421 case VCHR: 422 mode |= S_IFCHR; 423 break; 424 case VLNK: 425 mode |= S_IFLNK; 426 break; 427 case VSOCK: 428 mode |= S_IFSOCK; 429 break; 430 case VFIFO: 431 mode |= S_IFIFO; 432 break; 433 default: 434 return (EBADF); 435 } 436 sb->st_mode = mode; 437 sb->st_nlink = va.va_nlink; 438 sb->st_uid = va.va_uid; 439 sb->st_gid = va.va_gid; 440 sb->st_rdev = va.va_rdev; 441 sb->st_size = va.va_size; 442 sb->st_atim = va.va_atime; 443 sb->st_mtim = va.va_mtime; 444 sb->st_ctim = va.va_ctime; 445 sb->st_blksize = va.va_blocksize; 446 sb->st_flags = va.va_flags; 447 sb->st_gen = va.va_gen; 448 sb->st_blocks = va.va_bytes / S_BLKSIZE; 449 return (0); 450 } 451 452 /* 453 * File table vnode ioctl routine. 454 */ 455 int 456 vn_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p) 457 { 458 struct vnode *vp = ((struct vnode *)fp->f_data); 459 struct vattr vattr; 460 int error; 461 462 switch (vp->v_type) { 463 464 case VREG: 465 case VDIR: 466 if (com == FIONREAD) { 467 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 468 if (error) 469 return (error); 470 *(int *)data = vattr.va_size - fp->f_offset; 471 return (0); 472 } 473 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 474 return (0); /* XXX */ 475 /* FALLTHROUGH */ 476 default: 477 return (ENOTTY); 478 479 case VFIFO: 480 case VCHR: 481 case VBLK: 482 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 483 if (error == 0 && com == TIOCSCTTY) { 484 struct session *s = p->p_p->ps_session; 485 if (s->s_ttyvp) 486 vrele(s->s_ttyvp); 487 s->s_ttyvp = vp; 488 vref(vp); 489 } 490 return (error); 491 } 492 } 493 494 /* 495 * File table vnode poll routine. 496 */ 497 int 498 vn_poll(struct file *fp, int events, struct proc *p) 499 { 500 return (VOP_POLL(((struct vnode *)fp->f_data), events, p)); 501 } 502 503 /* 504 * Check that the vnode is still valid, and if so 505 * acquire requested lock. 506 */ 507 int 508 vn_lock(struct vnode *vp, int flags, struct proc *p) 509 { 510 int error; 511 512 if ((flags & LK_RECURSEFAIL) == 0) 513 flags |= LK_CANRECURSE; 514 515 do { 516 if (vp->v_flag & VXLOCK) { 517 vp->v_flag |= VXWANT; 518 tsleep(vp, PINOD, "vn_lock", 0); 519 error = ENOENT; 520 } else { 521 error = VOP_LOCK(vp, flags, p); 522 if (error == 0) 523 return (error); 524 } 525 } while (flags & LK_RETRY); 526 return (error); 527 } 528 529 /* 530 * File table vnode close routine. 531 */ 532 int 533 vn_closefile(struct file *fp, struct proc *p) 534 { 535 struct vnode *vp = fp->f_data; 536 struct flock lf; 537 538 if ((fp->f_flag & FHASLOCK)) { 539 lf.l_whence = SEEK_SET; 540 lf.l_start = 0; 541 lf.l_len = 0; 542 lf.l_type = F_UNLCK; 543 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 544 } 545 546 return (vn_close(vp, fp->f_flag, fp->f_cred, p)); 547 } 548 549 int 550 vn_kqfilter(struct file *fp, struct knote *kn) 551 { 552 return (VOP_KQFILTER(((struct vnode *)fp->f_data), kn)); 553 } 554 555 /* 556 * Common code for vnode access operations. 557 */ 558 559 /* Check if a directory can be found inside another in the hierarchy */ 560 int 561 vn_isunder(struct vnode *lvp, struct vnode *rvp, struct proc *p) 562 { 563 int error; 564 565 error = vfs_getcwd_common(lvp, rvp, NULL, NULL, MAXPATHLEN/2, 0, p); 566 567 if (!error) 568 return (1); 569 570 return (0); 571 } 572