1 /* $OpenBSD: vfs_vnops.c,v 1.39 2001/12/19 08:58:06 art 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. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)vfs_vnops.c 8.5 (Berkeley) 12/8/94 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/file.h> 48 #include <sys/stat.h> 49 #include <sys/buf.h> 50 #include <sys/proc.h> 51 #include <sys/mount.h> 52 #include <sys/namei.h> 53 #include <sys/vnode.h> 54 #include <sys/ioctl.h> 55 #include <sys/tty.h> 56 #include <sys/cdio.h> 57 58 #include <uvm/uvm_extern.h> 59 60 int vn_read __P((struct file *fp, off_t *off, struct uio *uio, 61 struct ucred *cred)); 62 int vn_write __P((struct file *fp, off_t *off, struct uio *uio, 63 struct ucred *cred)); 64 int vn_select __P((struct file *fp, int which, struct proc *p)); 65 int vn_kqfilter __P((struct file *fp, struct knote *kn)); 66 int vn_closefile __P((struct file *fp, struct proc *p)); 67 int vn_ioctl __P((struct file *fp, u_long com, caddr_t data, 68 struct proc *p)); 69 70 struct fileops vnops = 71 { vn_read, vn_write, vn_ioctl, vn_select, vn_kqfilter, vn_statfile, 72 vn_closefile }; 73 74 /* 75 * Common code for vnode open operations. 76 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 77 */ 78 int 79 vn_open(ndp, fmode, cmode) 80 register struct nameidata *ndp; 81 int fmode, cmode; 82 { 83 register struct vnode *vp; 84 register struct proc *p = ndp->ni_cnd.cn_proc; 85 register struct ucred *cred = p->p_ucred; 86 struct vattr va; 87 int error; 88 89 if ((fmode & (FREAD|FWRITE)) == 0) 90 return (EINVAL); 91 if ((fmode & (O_TRUNC | FWRITE)) == O_TRUNC) 92 return (EINVAL); 93 if (fmode & O_CREAT) { 94 ndp->ni_cnd.cn_nameiop = CREATE; 95 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 96 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 97 ndp->ni_cnd.cn_flags |= FOLLOW; 98 if ((error = namei(ndp)) != 0) 99 return (error); 100 101 if (ndp->ni_vp == NULL) { 102 VATTR_NULL(&va); 103 va.va_type = VREG; 104 va.va_mode = cmode; 105 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 106 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 107 &ndp->ni_cnd, &va); 108 if (error) 109 return (error); 110 fmode &= ~O_TRUNC; 111 vp = ndp->ni_vp; 112 } else { 113 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 114 if (ndp->ni_dvp == ndp->ni_vp) 115 vrele(ndp->ni_dvp); 116 else 117 vput(ndp->ni_dvp); 118 ndp->ni_dvp = NULL; 119 vp = ndp->ni_vp; 120 if (fmode & O_EXCL) { 121 error = EEXIST; 122 goto bad; 123 } 124 fmode &= ~O_CREAT; 125 } 126 } else { 127 ndp->ni_cnd.cn_nameiop = LOOKUP; 128 ndp->ni_cnd.cn_flags = 129 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 130 if ((error = namei(ndp)) != 0) 131 return (error); 132 vp = ndp->ni_vp; 133 } 134 if (vp->v_type == VSOCK) { 135 error = EOPNOTSUPP; 136 goto bad; 137 } 138 if (vp->v_type == VLNK) { 139 error = EMLINK; 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 VOP_UNLOCK(vp, 0, p); /* XXX */ 159 VOP_LEASE(vp, p, cred, LEASE_WRITE); 160 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); /* XXX */ 161 VATTR_NULL(&va); 162 va.va_size = 0; 163 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 164 goto bad; 165 } 166 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 167 goto bad; 168 if (fmode & FWRITE) 169 vp->v_writecount++; 170 return (0); 171 bad: 172 vput(vp); 173 return (error); 174 } 175 176 /* 177 * Check for write permissions on the specified vnode. 178 * Prototype text segments cannot be written. 179 */ 180 int 181 vn_writechk(vp) 182 register struct vnode *vp; 183 { 184 185 /* 186 * Disallow write attempts on read-only file systems; 187 * unless the file is a socket or a block or character 188 * device resident on the file system. 189 */ 190 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 191 switch (vp->v_type) { 192 case VREG: case VDIR: case VLNK: 193 return (EROFS); 194 case VNON: case VCHR: case VSOCK: 195 case VFIFO: case VBAD: case VBLK: 196 break; 197 } 198 } 199 /* 200 * If there's shared text associated with 201 * the vnode, try to free it up once. If 202 * we fail, we can't allow writing. 203 */ 204 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 205 return (ETXTBSY); 206 207 return (0); 208 } 209 210 /* 211 * Mark a vnode as being the text image of a running process. 212 */ 213 void 214 vn_marktext(vp) 215 struct vnode *vp; 216 { 217 vp->v_flag |= VTEXT; 218 } 219 220 /* 221 * Vnode close call 222 */ 223 int 224 vn_close(vp, flags, cred, p) 225 register struct vnode *vp; 226 int flags; 227 struct ucred *cred; 228 struct proc *p; 229 { 230 int error; 231 232 if (flags & FWRITE) 233 vp->v_writecount--; 234 error = VOP_CLOSE(vp, flags, cred, p); 235 vrele(vp); 236 return (error); 237 } 238 239 /* 240 * Package up an I/O request on a vnode into a uio and do it. 241 */ 242 int 243 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 244 enum uio_rw rw; 245 struct vnode *vp; 246 caddr_t base; 247 int len; 248 off_t offset; 249 enum uio_seg segflg; 250 int ioflg; 251 struct ucred *cred; 252 size_t *aresid; 253 struct proc *p; 254 { 255 struct uio auio; 256 struct iovec aiov; 257 int error; 258 259 if ((ioflg & IO_NODELOCKED) == 0) 260 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 261 auio.uio_iov = &aiov; 262 auio.uio_iovcnt = 1; 263 aiov.iov_base = base; 264 aiov.iov_len = len; 265 auio.uio_resid = len; 266 auio.uio_offset = offset; 267 auio.uio_segflg = segflg; 268 auio.uio_rw = rw; 269 auio.uio_procp = p; 270 if (rw == UIO_READ) { 271 error = VOP_READ(vp, &auio, ioflg, cred); 272 } else { 273 error = VOP_WRITE(vp, &auio, ioflg, cred); 274 } 275 if (aresid) 276 *aresid = auio.uio_resid; 277 else 278 if (auio.uio_resid && error == 0) 279 error = EIO; 280 if ((ioflg & IO_NODELOCKED) == 0) 281 VOP_UNLOCK(vp, 0, p); 282 return (error); 283 } 284 285 /* 286 * File table vnode read routine. 287 */ 288 int 289 vn_read(fp, poff, uio, cred) 290 struct file *fp; 291 off_t *poff; 292 struct uio *uio; 293 struct ucred *cred; 294 { 295 register struct vnode *vp = (struct vnode *)fp->f_data; 296 int error = 0; 297 size_t count; 298 struct proc *p = uio->uio_procp; 299 300 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_READ); 301 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 302 uio->uio_offset = *poff; 303 count = uio->uio_resid; 304 if (vp->v_type != VDIR) 305 error = VOP_READ(vp, uio, 306 (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, cred); 307 *poff += count - uio->uio_resid; 308 VOP_UNLOCK(vp, 0, p); 309 return (error); 310 } 311 312 /* 313 * File table vnode write routine. 314 */ 315 int 316 vn_write(fp, poff, uio, cred) 317 struct file *fp; 318 off_t *poff; 319 struct uio *uio; 320 struct ucred *cred; 321 { 322 register struct vnode *vp = (struct vnode *)fp->f_data; 323 struct proc *p = uio->uio_procp; 324 int error, ioflag = IO_UNIT; 325 size_t count; 326 327 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 328 ioflag |= IO_APPEND; 329 if (fp->f_flag & FNONBLOCK) 330 ioflag |= IO_NDELAY; 331 if ((fp->f_flag & FFSYNC) || 332 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 333 ioflag |= IO_SYNC; 334 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE); 335 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 336 uio->uio_offset = *poff; 337 count = uio->uio_resid; 338 error = VOP_WRITE(vp, uio, ioflag, cred); 339 if (ioflag & IO_APPEND) 340 *poff = uio->uio_offset; 341 else 342 *poff += count - uio->uio_resid; 343 VOP_UNLOCK(vp, 0, p); 344 return (error); 345 } 346 347 /* 348 * File table wrapper for vn_stat 349 */ 350 int 351 vn_statfile(fp, sb, p) 352 struct file *fp; 353 struct stat *sb; 354 struct proc *p; 355 { 356 struct vnode *vp = (struct vnode *)fp->f_data; 357 358 return vn_stat(vp, sb, p); 359 } 360 361 /* 362 * vnode stat routine. 363 */ 364 int 365 vn_stat(vp, sb, p) 366 struct vnode *vp; 367 register struct stat *sb; 368 struct proc *p; 369 { 370 struct vattr va; 371 int error; 372 u_short mode; 373 374 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 375 if (error) 376 return (error); 377 /* 378 * Copy from vattr table 379 */ 380 sb->st_dev = va.va_fsid; 381 sb->st_ino = va.va_fileid; 382 mode = va.va_mode; 383 switch (vp->v_type) { 384 case VREG: 385 mode |= S_IFREG; 386 break; 387 case VDIR: 388 mode |= S_IFDIR; 389 break; 390 case VBLK: 391 mode |= S_IFBLK; 392 break; 393 case VCHR: 394 mode |= S_IFCHR; 395 break; 396 case VLNK: 397 mode |= S_IFLNK; 398 break; 399 case VSOCK: 400 mode |= S_IFSOCK; 401 break; 402 case VFIFO: 403 mode |= S_IFIFO; 404 break; 405 default: 406 return (EBADF); 407 } 408 sb->st_mode = mode; 409 sb->st_nlink = va.va_nlink; 410 sb->st_uid = va.va_uid; 411 sb->st_gid = va.va_gid; 412 sb->st_rdev = va.va_rdev; 413 sb->st_size = va.va_size; 414 sb->st_atimespec = va.va_atime; 415 sb->st_mtimespec = va.va_mtime; 416 sb->st_ctimespec = va.va_ctime; 417 sb->st_blksize = va.va_blocksize; 418 sb->st_flags = va.va_flags; 419 sb->st_gen = va.va_gen; 420 sb->st_blocks = va.va_bytes / S_BLKSIZE; 421 return (0); 422 } 423 424 /* 425 * File table vnode ioctl routine. 426 */ 427 int 428 vn_ioctl(fp, com, data, p) 429 struct file *fp; 430 u_long com; 431 caddr_t data; 432 struct proc *p; 433 { 434 register struct vnode *vp = ((struct vnode *)fp->f_data); 435 struct vattr vattr; 436 int error; 437 438 switch (vp->v_type) { 439 440 case VREG: 441 case VDIR: 442 if (com == FIONREAD) { 443 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 444 if (error) 445 return (error); 446 *(int *)data = vattr.va_size - fp->f_offset; 447 return (0); 448 } 449 if (com == FIBMAP) 450 return VOP_IOCTL(vp, com, data, fp->f_flag, 451 p->p_ucred, p); 452 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 453 return (0); /* XXX */ 454 /* fall into... */ 455 456 default: 457 return (ENOTTY); 458 459 case VFIFO: 460 case VCHR: 461 case VBLK: 462 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 463 if (error == 0 && com == TIOCSCTTY) { 464 if (p->p_session->s_ttyvp) 465 vrele(p->p_session->s_ttyvp); 466 p->p_session->s_ttyvp = vp; 467 VREF(vp); 468 } 469 return (error); 470 } 471 } 472 473 /* 474 * File table vnode select routine. 475 */ 476 int 477 vn_select(fp, which, p) 478 struct file *fp; 479 int which; 480 struct proc *p; 481 { 482 483 return (VOP_SELECT(((struct vnode *)fp->f_data), which, fp->f_flag, 484 fp->f_cred, p)); 485 } 486 487 /* 488 * Check that the vnode is still valid, and if so 489 * acquire requested lock. 490 */ 491 int 492 vn_lock(vp, flags, p) 493 struct vnode *vp; 494 int flags; 495 struct proc *p; 496 { 497 int error; 498 499 do { 500 if ((flags & LK_INTERLOCK) == 0) 501 simple_lock(&vp->v_interlock); 502 if (vp->v_flag & VXLOCK) { 503 vp->v_flag |= VXWANT; 504 simple_unlock(&vp->v_interlock); 505 tsleep((caddr_t)vp, PINOD, "vn_lock", 0); 506 error = ENOENT; 507 } else { 508 error = VOP_LOCK(vp, flags | LK_INTERLOCK | LK_CANRECURSE, p); 509 if (error == 0) 510 return (error); 511 } 512 flags &= ~LK_INTERLOCK; 513 } while (flags & LK_RETRY); 514 return (error); 515 } 516 517 /* 518 * File table vnode close routine. 519 */ 520 int 521 vn_closefile(fp, p) 522 struct file *fp; 523 struct proc *p; 524 { 525 526 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 527 fp->f_cred, p)); 528 } 529 530 /*ARGSUSED*/ 531 int 532 vn_kqfilter(struct file *fp, struct knote *kn) 533 { 534 return (VOP_KQFILTER(((struct vnode *)fp->f_data), kn)); 535 } 536