1 /* $OpenBSD: vfs_vnops.c,v 1.43 2003/07/21 22:44:50 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/file.h> 44 #include <sys/stat.h> 45 #include <sys/buf.h> 46 #include <sys/proc.h> 47 #include <sys/mount.h> 48 #include <sys/namei.h> 49 #include <sys/vnode.h> 50 #include <sys/ioctl.h> 51 #include <sys/tty.h> 52 #include <sys/cdio.h> 53 54 #include <uvm/uvm_extern.h> 55 56 int vn_read(struct file *fp, off_t *off, struct uio *uio, 57 struct ucred *cred); 58 int vn_write(struct file *fp, off_t *off, struct uio *uio, 59 struct ucred *cred); 60 int vn_select(struct file *fp, int which, struct proc *p); 61 int vn_kqfilter(struct file *fp, struct knote *kn); 62 int vn_closefile(struct file *fp, struct proc *p); 63 int vn_ioctl(struct file *fp, u_long com, caddr_t data, 64 struct proc *p); 65 66 struct fileops vnops = 67 { vn_read, vn_write, vn_ioctl, vn_select, 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(ndp, fmode, cmode) 76 register struct nameidata *ndp; 77 int fmode, cmode; 78 { 79 register struct vnode *vp; 80 register struct proc *p = ndp->ni_cnd.cn_proc; 81 register struct ucred *cred = p->p_ucred; 82 struct vattr va; 83 int error; 84 85 if ((fmode & (FREAD|FWRITE)) == 0) 86 return (EINVAL); 87 if ((fmode & (O_TRUNC | FWRITE)) == O_TRUNC) 88 return (EINVAL); 89 if (fmode & O_CREAT) { 90 ndp->ni_cnd.cn_nameiop = CREATE; 91 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 92 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 93 ndp->ni_cnd.cn_flags |= FOLLOW; 94 if ((error = namei(ndp)) != 0) 95 return (error); 96 97 if (ndp->ni_vp == NULL) { 98 VATTR_NULL(&va); 99 va.va_type = VREG; 100 va.va_mode = cmode; 101 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 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 = EMLINK; 136 goto bad; 137 } 138 if ((fmode & O_CREAT) == 0) { 139 if (fmode & FREAD) { 140 if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) 141 goto bad; 142 } 143 if (fmode & FWRITE) { 144 if (vp->v_type == VDIR) { 145 error = EISDIR; 146 goto bad; 147 } 148 if ((error = vn_writechk(vp)) != 0 || 149 (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) 150 goto bad; 151 } 152 } 153 if ((fmode & O_TRUNC) && vp->v_type == VREG) { 154 VOP_UNLOCK(vp, 0, p); /* XXX */ 155 VOP_LEASE(vp, p, cred, LEASE_WRITE); 156 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); /* XXX */ 157 VATTR_NULL(&va); 158 va.va_size = 0; 159 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 160 goto bad; 161 } 162 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 163 goto bad; 164 if (fmode & FWRITE) 165 vp->v_writecount++; 166 return (0); 167 bad: 168 vput(vp); 169 return (error); 170 } 171 172 /* 173 * Check for write permissions on the specified vnode. 174 * Prototype text segments cannot be written. 175 */ 176 int 177 vn_writechk(vp) 178 register struct vnode *vp; 179 { 180 181 /* 182 * Disallow write attempts on read-only file systems; 183 * unless the file is a socket or a block or character 184 * device resident on the file system. 185 */ 186 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 187 switch (vp->v_type) { 188 case VREG: case VDIR: case VLNK: 189 return (EROFS); 190 case VNON: case VCHR: case VSOCK: 191 case VFIFO: case VBAD: case VBLK: 192 break; 193 } 194 } 195 /* 196 * If there's shared text associated with 197 * the vnode, try to free it up once. If 198 * we fail, we can't allow writing. 199 */ 200 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 201 return (ETXTBSY); 202 203 return (0); 204 } 205 206 /* 207 * Mark a vnode as being the text image of a running process. 208 */ 209 void 210 vn_marktext(vp) 211 struct vnode *vp; 212 { 213 vp->v_flag |= VTEXT; 214 } 215 216 /* 217 * Vnode close call 218 */ 219 int 220 vn_close(vp, flags, cred, p) 221 register struct vnode *vp; 222 int flags; 223 struct ucred *cred; 224 struct proc *p; 225 { 226 int error; 227 228 if (flags & FWRITE) 229 vp->v_writecount--; 230 error = VOP_CLOSE(vp, flags, cred, p); 231 vrele(vp); 232 return (error); 233 } 234 235 /* 236 * Package up an I/O request on a vnode into a uio and do it. 237 */ 238 int 239 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 240 enum uio_rw rw; 241 struct vnode *vp; 242 caddr_t base; 243 int len; 244 off_t offset; 245 enum uio_seg segflg; 246 int ioflg; 247 struct ucred *cred; 248 size_t *aresid; 249 struct proc *p; 250 { 251 struct uio auio; 252 struct iovec aiov; 253 int error; 254 255 if ((ioflg & IO_NODELOCKED) == 0) 256 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 257 auio.uio_iov = &aiov; 258 auio.uio_iovcnt = 1; 259 aiov.iov_base = base; 260 aiov.iov_len = len; 261 auio.uio_resid = len; 262 auio.uio_offset = offset; 263 auio.uio_segflg = segflg; 264 auio.uio_rw = rw; 265 auio.uio_procp = p; 266 if (rw == UIO_READ) { 267 error = VOP_READ(vp, &auio, ioflg, cred); 268 } else { 269 error = VOP_WRITE(vp, &auio, ioflg, cred); 270 } 271 if (aresid) 272 *aresid = auio.uio_resid; 273 else 274 if (auio.uio_resid && error == 0) 275 error = EIO; 276 if ((ioflg & IO_NODELOCKED) == 0) 277 VOP_UNLOCK(vp, 0, p); 278 return (error); 279 } 280 281 /* 282 * File table vnode read routine. 283 */ 284 int 285 vn_read(fp, poff, uio, cred) 286 struct file *fp; 287 off_t *poff; 288 struct uio *uio; 289 struct ucred *cred; 290 { 291 register struct vnode *vp = (struct vnode *)fp->f_data; 292 int error = 0; 293 size_t count; 294 struct proc *p = uio->uio_procp; 295 296 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_READ); 297 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 298 uio->uio_offset = *poff; 299 count = uio->uio_resid; 300 if (vp->v_type != VDIR) 301 error = VOP_READ(vp, uio, 302 (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, cred); 303 *poff += count - uio->uio_resid; 304 VOP_UNLOCK(vp, 0, p); 305 return (error); 306 } 307 308 /* 309 * File table vnode write routine. 310 */ 311 int 312 vn_write(fp, poff, uio, cred) 313 struct file *fp; 314 off_t *poff; 315 struct uio *uio; 316 struct ucred *cred; 317 { 318 register struct vnode *vp = (struct vnode *)fp->f_data; 319 struct proc *p = uio->uio_procp; 320 int error, ioflag = IO_UNIT; 321 size_t count; 322 323 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 324 ioflag |= IO_APPEND; 325 if (fp->f_flag & FNONBLOCK) 326 ioflag |= IO_NDELAY; 327 if ((fp->f_flag & FFSYNC) || 328 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 329 ioflag |= IO_SYNC; 330 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE); 331 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 332 uio->uio_offset = *poff; 333 count = uio->uio_resid; 334 error = VOP_WRITE(vp, uio, ioflag, cred); 335 if (ioflag & IO_APPEND) 336 *poff = uio->uio_offset; 337 else 338 *poff += count - uio->uio_resid; 339 VOP_UNLOCK(vp, 0, p); 340 return (error); 341 } 342 343 /* 344 * File table wrapper for vn_stat 345 */ 346 int 347 vn_statfile(fp, sb, p) 348 struct file *fp; 349 struct stat *sb; 350 struct proc *p; 351 { 352 struct vnode *vp = (struct vnode *)fp->f_data; 353 354 return vn_stat(vp, sb, p); 355 } 356 357 /* 358 * vnode stat routine. 359 */ 360 int 361 vn_stat(vp, sb, p) 362 struct vnode *vp; 363 register struct stat *sb; 364 struct proc *p; 365 { 366 struct vattr va; 367 int error; 368 u_short mode; 369 370 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 371 if (error) 372 return (error); 373 /* 374 * Copy from vattr table 375 */ 376 sb->st_dev = va.va_fsid; 377 sb->st_ino = va.va_fileid; 378 mode = va.va_mode; 379 switch (vp->v_type) { 380 case VREG: 381 mode |= S_IFREG; 382 break; 383 case VDIR: 384 mode |= S_IFDIR; 385 break; 386 case VBLK: 387 mode |= S_IFBLK; 388 break; 389 case VCHR: 390 mode |= S_IFCHR; 391 break; 392 case VLNK: 393 mode |= S_IFLNK; 394 break; 395 case VSOCK: 396 mode |= S_IFSOCK; 397 break; 398 case VFIFO: 399 mode |= S_IFIFO; 400 break; 401 default: 402 return (EBADF); 403 } 404 sb->st_mode = mode; 405 sb->st_nlink = va.va_nlink; 406 sb->st_uid = va.va_uid; 407 sb->st_gid = va.va_gid; 408 sb->st_rdev = va.va_rdev; 409 sb->st_size = va.va_size; 410 sb->st_atimespec = va.va_atime; 411 sb->st_mtimespec = va.va_mtime; 412 sb->st_ctimespec = va.va_ctime; 413 sb->st_blksize = va.va_blocksize; 414 sb->st_flags = va.va_flags; 415 sb->st_gen = va.va_gen; 416 sb->st_blocks = va.va_bytes / S_BLKSIZE; 417 return (0); 418 } 419 420 /* 421 * File table vnode ioctl routine. 422 */ 423 int 424 vn_ioctl(fp, com, data, p) 425 struct file *fp; 426 u_long com; 427 caddr_t data; 428 struct proc *p; 429 { 430 register struct vnode *vp = ((struct vnode *)fp->f_data); 431 struct vattr vattr; 432 int error; 433 434 switch (vp->v_type) { 435 436 case VREG: 437 case VDIR: 438 if (com == FIONREAD) { 439 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 440 if (error) 441 return (error); 442 *(int *)data = vattr.va_size - fp->f_offset; 443 return (0); 444 } 445 if (com == FIBMAP) 446 return VOP_IOCTL(vp, com, data, fp->f_flag, 447 p->p_ucred, p); 448 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 449 return (0); /* XXX */ 450 /* fall into... */ 451 452 default: 453 return (ENOTTY); 454 455 case VFIFO: 456 case VCHR: 457 case VBLK: 458 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 459 if (error == 0 && com == TIOCSCTTY) { 460 if (p->p_session->s_ttyvp) 461 vrele(p->p_session->s_ttyvp); 462 p->p_session->s_ttyvp = vp; 463 VREF(vp); 464 } 465 return (error); 466 } 467 } 468 469 /* 470 * File table vnode select routine. 471 */ 472 int 473 vn_select(fp, which, p) 474 struct file *fp; 475 int which; 476 struct proc *p; 477 { 478 479 return (VOP_SELECT(((struct vnode *)fp->f_data), which, fp->f_flag, 480 fp->f_cred, p)); 481 } 482 483 /* 484 * Check that the vnode is still valid, and if so 485 * acquire requested lock. 486 */ 487 int 488 vn_lock(struct vnode *vp, int flags, struct proc *p) 489 { 490 int error; 491 492 if ((flags & LK_RECURSEFAIL) == 0) 493 flags |= LK_CANRECURSE; 494 495 do { 496 if ((flags & LK_INTERLOCK) == 0) 497 simple_lock(&vp->v_interlock); 498 if (vp->v_flag & VXLOCK) { 499 vp->v_flag |= VXWANT; 500 simple_unlock(&vp->v_interlock); 501 tsleep(vp, PINOD, "vn_lock", 0); 502 error = ENOENT; 503 } else { 504 error = VOP_LOCK(vp, flags | LK_INTERLOCK, p); 505 if (error == 0) 506 return (error); 507 } 508 flags &= ~LK_INTERLOCK; 509 } while (flags & LK_RETRY); 510 return (error); 511 } 512 513 /* 514 * File table vnode close routine. 515 */ 516 int 517 vn_closefile(fp, p) 518 struct file *fp; 519 struct proc *p; 520 { 521 522 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 523 fp->f_cred, p)); 524 } 525 526 /*ARGSUSED*/ 527 int 528 vn_kqfilter(struct file *fp, struct knote *kn) 529 { 530 return (VOP_KQFILTER(((struct vnode *)fp->f_data), kn)); 531 } 532