1 /* $OpenBSD: vfs_vnops.c,v 1.78 2014/07/13 15:00:40 tedu 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 int vn_read(struct file *, off_t *, struct uio *, struct ucred *); 61 int vn_write(struct file *, off_t *, struct uio *, struct ucred *); 62 int vn_poll(struct file *, int, struct proc *); 63 int vn_kqfilter(struct file *, struct knote *); 64 int vn_closefile(struct file *, struct proc *); 65 66 struct fileops vnops = 67 { vn_read, vn_write, vn_ioctl, vn_poll, vn_kqfilter, vn_statfile, 68 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(struct nameidata *ndp, int fmode, int cmode) 76 { 77 struct vnode *vp; 78 struct proc *p = ndp->ni_cnd.cn_proc; 79 struct ucred *cred = p->p_ucred; 80 struct vattr va; 81 struct cloneinfo *cip; 82 int error; 83 84 if ((fmode & (FREAD|FWRITE)) == 0) 85 return (EINVAL); 86 if ((fmode & (O_TRUNC | FWRITE)) == O_TRUNC) 87 return (EINVAL); 88 if (fmode & O_CREAT) { 89 ndp->ni_cnd.cn_nameiop = CREATE; 90 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 91 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 92 ndp->ni_cnd.cn_flags |= FOLLOW; 93 if ((error = namei(ndp)) != 0) 94 return (error); 95 96 if (ndp->ni_vp == NULL) { 97 VATTR_NULL(&va); 98 va.va_type = VREG; 99 va.va_mode = cmode; 100 if (fmode & O_EXCL) 101 va.va_vaflags |= VA_EXCLUSIVE; 102 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 103 &ndp->ni_cnd, &va); 104 if (error) 105 return (error); 106 fmode &= ~O_TRUNC; 107 vp = ndp->ni_vp; 108 } else { 109 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 110 if (ndp->ni_dvp == ndp->ni_vp) 111 vrele(ndp->ni_dvp); 112 else 113 vput(ndp->ni_dvp); 114 ndp->ni_dvp = NULL; 115 vp = ndp->ni_vp; 116 if (fmode & O_EXCL) { 117 error = EEXIST; 118 goto bad; 119 } 120 fmode &= ~O_CREAT; 121 } 122 } else { 123 ndp->ni_cnd.cn_nameiop = LOOKUP; 124 ndp->ni_cnd.cn_flags = 125 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 126 if ((error = namei(ndp)) != 0) 127 return (error); 128 vp = ndp->ni_vp; 129 } 130 if (vp->v_type == VSOCK) { 131 error = EOPNOTSUPP; 132 goto bad; 133 } 134 if (vp->v_type == VLNK) { 135 error = ELOOP; 136 goto bad; 137 } 138 if ((fmode & O_DIRECTORY) && vp->v_type != VDIR) { 139 error = ENOTDIR; 140 goto bad; 141 } 142 if ((fmode & O_CREAT) == 0) { 143 if (fmode & FREAD) { 144 if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) 145 goto bad; 146 } 147 if (fmode & FWRITE) { 148 if (vp->v_type == VDIR) { 149 error = EISDIR; 150 goto bad; 151 } 152 if ((error = vn_writechk(vp)) != 0 || 153 (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) 154 goto bad; 155 } 156 } 157 if ((fmode & O_TRUNC) && vp->v_type == VREG) { 158 VATTR_NULL(&va); 159 va.va_size = 0; 160 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 161 goto bad; 162 } 163 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 164 goto bad; 165 166 if (vp->v_flag & VCLONED) { 167 cip = (struct cloneinfo *)vp->v_data; 168 169 vp->v_flag &= ~VCLONED; 170 171 ndp->ni_vp = cip->ci_vp; /* return cloned vnode */ 172 vp->v_data = cip->ci_data; /* restore v_data */ 173 VOP_UNLOCK(vp, 0, p); /* keep a reference */ 174 vp = ndp->ni_vp; /* for the increment below */ 175 176 free(cip, M_TEMP, sizeof(*cip)); 177 } 178 179 if (fmode & FWRITE) 180 vp->v_writecount++; 181 return (0); 182 bad: 183 vput(vp); 184 return (error); 185 } 186 187 /* 188 * Check for write permissions on the specified vnode. 189 * Prototype text segments cannot be written. 190 */ 191 int 192 vn_writechk(struct vnode *vp) 193 { 194 /* 195 * Disallow write attempts on read-only file systems; 196 * unless the file is a socket or a block or character 197 * device resident on the file system. 198 */ 199 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 200 switch (vp->v_type) { 201 case VREG: 202 case VDIR: 203 case VLNK: 204 return (EROFS); 205 case VNON: 206 case VCHR: 207 case VSOCK: 208 case VFIFO: 209 case VBAD: 210 case VBLK: 211 break; 212 } 213 } 214 /* 215 * If there's shared text associated with 216 * the vnode, try to free it up once. If 217 * we fail, we can't allow writing. 218 */ 219 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 220 return (ETXTBSY); 221 222 return (0); 223 } 224 225 /* 226 * Check whether a write operation would exceed the file size rlimit 227 * for the process, if one should be applied for this operation. 228 * If a partial write should take place, the uio is adjusted and the 229 * amount by which the request would have exceeded the limit is returned 230 * via the 'overrun' argument. 231 */ 232 int 233 vn_fsizechk(struct vnode *vp, struct uio *uio, int ioflag, ssize_t *overrun) 234 { 235 struct proc *p = uio->uio_procp; 236 237 *overrun = 0; 238 if (vp->v_type == VREG && p != NULL && !(ioflag & IO_NOLIMIT)) { 239 rlim_t limit = p->p_rlimit[RLIMIT_FSIZE].rlim_cur; 240 241 /* if already at or over the limit, send the signal and fail */ 242 if (uio->uio_offset >= limit) { 243 psignal(p, SIGXFSZ); 244 return (EFBIG); 245 } 246 247 /* otherwise, clamp the write to stay under the limit */ 248 if (uio->uio_resid > limit - uio->uio_offset) { 249 *overrun = uio->uio_resid - (limit - uio->uio_offset); 250 uio->uio_resid = limit - uio->uio_offset; 251 } 252 } 253 254 return (0); 255 } 256 257 258 /* 259 * Mark a vnode as being the text image of a running process. 260 */ 261 void 262 vn_marktext(struct vnode *vp) 263 { 264 vp->v_flag |= VTEXT; 265 } 266 267 /* 268 * Vnode close call 269 */ 270 int 271 vn_close(struct vnode *vp, int flags, struct ucred *cred, struct proc *p) 272 { 273 int error; 274 275 if (flags & FWRITE) 276 vp->v_writecount--; 277 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 278 error = VOP_CLOSE(vp, flags, cred, p); 279 vput(vp); 280 return (error); 281 } 282 283 /* 284 * Package up an I/O request on a vnode into a uio and do it. 285 */ 286 int 287 vn_rdwr(enum uio_rw rw, struct vnode *vp, caddr_t base, int len, off_t offset, 288 enum uio_seg segflg, int ioflg, struct ucred *cred, size_t *aresid, 289 struct proc *p) 290 { 291 struct uio auio; 292 struct iovec aiov; 293 int error; 294 295 auio.uio_iov = &aiov; 296 auio.uio_iovcnt = 1; 297 aiov.iov_base = base; 298 aiov.iov_len = len; 299 auio.uio_resid = len; 300 auio.uio_offset = offset; 301 auio.uio_segflg = segflg; 302 auio.uio_rw = rw; 303 auio.uio_procp = p; 304 305 if ((ioflg & IO_NODELOCKED) == 0) 306 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 307 if (rw == UIO_READ) { 308 error = VOP_READ(vp, &auio, ioflg, cred); 309 } else { 310 error = VOP_WRITE(vp, &auio, ioflg, cred); 311 } 312 if ((ioflg & IO_NODELOCKED) == 0) 313 VOP_UNLOCK(vp, 0, p); 314 315 if (aresid) 316 *aresid = auio.uio_resid; 317 else 318 if (auio.uio_resid && error == 0) 319 error = EIO; 320 return (error); 321 } 322 323 /* 324 * File table vnode read routine. 325 */ 326 int 327 vn_read(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred) 328 { 329 struct vnode *vp = (struct vnode *)fp->f_data; 330 int error = 0; 331 size_t count = uio->uio_resid; 332 struct proc *p = uio->uio_procp; 333 334 /* no wrap around of offsets except on character devices */ 335 if (vp->v_type != VCHR && count > LLONG_MAX - *poff) 336 return (EINVAL); 337 338 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 339 uio->uio_offset = *poff; 340 if (vp->v_type != VDIR) 341 error = VOP_READ(vp, uio, 342 (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, cred); 343 *poff += count - uio->uio_resid; 344 VOP_UNLOCK(vp, 0, p); 345 return (error); 346 } 347 348 /* 349 * File table vnode write routine. 350 */ 351 int 352 vn_write(struct file *fp, off_t *poff, struct uio *uio, struct ucred *cred) 353 { 354 struct vnode *vp = (struct vnode *)fp->f_data; 355 struct proc *p = uio->uio_procp; 356 int error, ioflag = IO_UNIT; 357 size_t count; 358 359 /* note: pwrite/pwritev are unaffected by O_APPEND */ 360 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) && 361 poff == &fp->f_offset) 362 ioflag |= IO_APPEND; 363 if (fp->f_flag & FNONBLOCK) 364 ioflag |= IO_NDELAY; 365 if ((fp->f_flag & FFSYNC) || 366 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 367 ioflag |= IO_SYNC; 368 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 369 uio->uio_offset = *poff; 370 count = uio->uio_resid; 371 error = VOP_WRITE(vp, uio, ioflag, cred); 372 if (ioflag & IO_APPEND) 373 *poff = uio->uio_offset; 374 else 375 *poff += count - uio->uio_resid; 376 VOP_UNLOCK(vp, 0, p); 377 return (error); 378 } 379 380 /* 381 * File table wrapper for vn_stat 382 */ 383 int 384 vn_statfile(struct file *fp, struct stat *sb, struct proc *p) 385 { 386 struct vnode *vp = (struct vnode *)fp->f_data; 387 return vn_stat(vp, sb, p); 388 } 389 390 /* 391 * vnode stat routine. 392 */ 393 int 394 vn_stat(struct vnode *vp, struct stat *sb, struct proc *p) 395 { 396 struct vattr va; 397 int error; 398 mode_t mode; 399 400 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 401 if (error) 402 return (error); 403 /* 404 * Copy from vattr table 405 */ 406 memset(sb, 0, sizeof(*sb)); 407 sb->st_dev = va.va_fsid; 408 sb->st_ino = va.va_fileid; 409 mode = va.va_mode; 410 switch (vp->v_type) { 411 case VREG: 412 mode |= S_IFREG; 413 break; 414 case VDIR: 415 mode |= S_IFDIR; 416 break; 417 case VBLK: 418 mode |= S_IFBLK; 419 break; 420 case VCHR: 421 mode |= S_IFCHR; 422 break; 423 case VLNK: 424 mode |= S_IFLNK; 425 break; 426 case VSOCK: 427 mode |= S_IFSOCK; 428 break; 429 case VFIFO: 430 mode |= S_IFIFO; 431 break; 432 default: 433 return (EBADF); 434 } 435 sb->st_mode = mode; 436 sb->st_nlink = va.va_nlink; 437 sb->st_uid = va.va_uid; 438 sb->st_gid = va.va_gid; 439 sb->st_rdev = va.va_rdev; 440 sb->st_size = va.va_size; 441 sb->st_atim.tv_sec = va.va_atime.tv_sec; 442 sb->st_atim.tv_nsec = va.va_atime.tv_nsec; 443 sb->st_mtim.tv_sec = va.va_mtime.tv_sec; 444 sb->st_mtim.tv_nsec = va.va_mtime.tv_nsec; 445 sb->st_ctim.tv_sec = va.va_ctime.tv_sec; 446 sb->st_ctim.tv_nsec = va.va_ctime.tv_nsec; 447 sb->st_blksize = va.va_blocksize; 448 sb->st_flags = va.va_flags; 449 sb->st_gen = va.va_gen; 450 sb->st_blocks = va.va_bytes / S_BLKSIZE; 451 return (0); 452 } 453 454 /* 455 * File table vnode ioctl routine. 456 */ 457 int 458 vn_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p) 459 { 460 struct vnode *vp = ((struct vnode *)fp->f_data); 461 struct vattr vattr; 462 int error; 463 464 switch (vp->v_type) { 465 466 case VREG: 467 case VDIR: 468 if (com == FIONREAD) { 469 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 470 if (error) 471 return (error); 472 *(int *)data = vattr.va_size - fp->f_offset; 473 return (0); 474 } 475 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 476 return (0); /* XXX */ 477 /* FALLTHROUGH */ 478 default: 479 return (ENOTTY); 480 481 case VFIFO: 482 case VCHR: 483 case VBLK: 484 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 485 if (error == 0 && com == TIOCSCTTY) { 486 struct session *s = p->p_p->ps_session; 487 struct vnode *ovp = s->s_ttyvp; 488 s->s_ttyvp = vp; 489 vref(vp); 490 if (ovp) 491 vrele(ovp); 492 } 493 return (error); 494 } 495 } 496 497 /* 498 * File table vnode poll routine. 499 */ 500 int 501 vn_poll(struct file *fp, int events, struct proc *p) 502 { 503 return (VOP_POLL(((struct vnode *)fp->f_data), events, p)); 504 } 505 506 /* 507 * Check that the vnode is still valid, and if so 508 * acquire requested lock. 509 */ 510 int 511 vn_lock(struct vnode *vp, int flags, struct proc *p) 512 { 513 int error; 514 515 if ((flags & LK_RECURSEFAIL) == 0) 516 flags |= LK_CANRECURSE; 517 518 do { 519 if (vp->v_flag & VXLOCK) { 520 vp->v_flag |= VXWANT; 521 tsleep(vp, PINOD, "vn_lock", 0); 522 error = ENOENT; 523 } else { 524 error = VOP_LOCK(vp, flags, p); 525 if (error == 0) 526 return (error); 527 } 528 } while (flags & LK_RETRY); 529 return (error); 530 } 531 532 /* 533 * File table vnode close routine. 534 */ 535 int 536 vn_closefile(struct file *fp, struct proc *p) 537 { 538 struct vnode *vp = fp->f_data; 539 struct flock lf; 540 541 if ((fp->f_iflags & FIF_HASLOCK)) { 542 lf.l_whence = SEEK_SET; 543 lf.l_start = 0; 544 lf.l_len = 0; 545 lf.l_type = F_UNLCK; 546 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 547 } 548 549 return (vn_close(vp, fp->f_flag, fp->f_cred, p)); 550 } 551 552 int 553 vn_kqfilter(struct file *fp, struct knote *kn) 554 { 555 return (VOP_KQFILTER(((struct vnode *)fp->f_data), kn)); 556 } 557 558 /* 559 * Common code for vnode access operations. 560 */ 561 562 /* Check if a directory can be found inside another in the hierarchy */ 563 int 564 vn_isunder(struct vnode *lvp, struct vnode *rvp, struct proc *p) 565 { 566 int error; 567 568 error = vfs_getcwd_common(lvp, rvp, NULL, NULL, MAXPATHLEN/2, 0, p); 569 570 if (!error) 571 return (1); 572 573 return (0); 574 } 575