vfs_vnops.c revision 1.26
1 /* $NetBSD: vfs_vnops.c,v 1.26 1998/02/10 14:09:57 mrg 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 8.5 (Berkeley) 12/8/94 41 */ 42 43 #include "opt_uvm.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 #if defined(UVM) 62 #include <uvm/uvm_extern.h> 63 #endif 64 65 struct fileops vnops = 66 { vn_read, vn_write, vn_ioctl, vn_poll, vn_closefile }; 67 68 /* 69 * Common code for vnode open operations. 70 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 71 */ 72 int 73 vn_open(ndp, fmode, cmode) 74 register struct nameidata *ndp; 75 int fmode, cmode; 76 { 77 register struct vnode *vp; 78 register struct proc *p = ndp->ni_cnd.cn_proc; 79 register struct ucred *cred = p->p_ucred; 80 struct vattr va; 81 int error; 82 83 if (fmode & O_CREAT) { 84 ndp->ni_cnd.cn_nameiop = CREATE; 85 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 86 if ((fmode & O_EXCL) == 0) 87 ndp->ni_cnd.cn_flags |= FOLLOW; 88 if ((error = namei(ndp)) != 0) 89 return (error); 90 if (ndp->ni_vp == NULL) { 91 VATTR_NULL(&va); 92 va.va_type = VREG; 93 va.va_mode = cmode; 94 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 95 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 96 &ndp->ni_cnd, &va); 97 if (error) 98 return (error); 99 fmode &= ~O_TRUNC; 100 vp = ndp->ni_vp; 101 } else { 102 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 103 if (ndp->ni_dvp == ndp->ni_vp) 104 vrele(ndp->ni_dvp); 105 else 106 vput(ndp->ni_dvp); 107 ndp->ni_dvp = NULL; 108 vp = ndp->ni_vp; 109 if (fmode & O_EXCL) { 110 error = EEXIST; 111 goto bad; 112 } 113 fmode &= ~O_CREAT; 114 } 115 } else { 116 ndp->ni_cnd.cn_nameiop = LOOKUP; 117 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF; 118 if ((error = namei(ndp)) != 0) 119 return (error); 120 vp = ndp->ni_vp; 121 } 122 if (vp->v_type == VSOCK) { 123 error = EOPNOTSUPP; 124 goto bad; 125 } 126 if ((fmode & O_CREAT) == 0) { 127 if (fmode & FREAD) { 128 if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0) 129 goto bad; 130 } 131 if (fmode & (FWRITE | O_TRUNC)) { 132 if (vp->v_type == VDIR) { 133 error = EISDIR; 134 goto bad; 135 } 136 if ((error = vn_writechk(vp)) != 0 || 137 (error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0) 138 goto bad; 139 } 140 } 141 if (fmode & O_TRUNC) { 142 VOP_UNLOCK(vp); /* XXX */ 143 VOP_LEASE(vp, p, cred, LEASE_WRITE); 144 VOP_LOCK(vp); /* XXX */ 145 VATTR_NULL(&va); 146 va.va_size = 0; 147 if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0) 148 goto bad; 149 } 150 if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0) 151 goto bad; 152 if (fmode & FWRITE) 153 vp->v_writecount++; 154 return (0); 155 bad: 156 vput(vp); 157 return (error); 158 } 159 160 /* 161 * Check for write permissions on the specified vnode. 162 * The read-only status of the file system is checked. 163 * Also, prototype text segments cannot be written. 164 */ 165 int 166 vn_writechk(vp) 167 register struct vnode *vp; 168 { 169 170 /* 171 * Disallow write attempts on read-only file systems; 172 * unless the file is a socket or a block or character 173 * device resident on the file system. 174 */ 175 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 176 switch (vp->v_type) { 177 case VREG: case VDIR: case VLNK: 178 return (EROFS); 179 case VNON: case VCHR: case VSOCK: 180 case VFIFO: case VBAD: case VBLK: 181 break; 182 } 183 } 184 /* 185 * If there's shared text associated with 186 * the vnode, try to free it up once. If 187 * we fail, we can't allow writing. 188 */ 189 #if defined(UVM) 190 if ((vp->v_flag & VTEXT) && !uvm_vnp_uncache(vp)) 191 return (ETXTBSY); 192 #else 193 if ((vp->v_flag & VTEXT) && !vnode_pager_uncache(vp)) 194 return (ETXTBSY); 195 #endif 196 return (0); 197 } 198 199 /* 200 * Vnode close call 201 */ 202 int 203 vn_close(vp, flags, cred, p) 204 register struct vnode *vp; 205 int flags; 206 struct ucred *cred; 207 struct proc *p; 208 { 209 int error; 210 211 if (flags & FWRITE) 212 vp->v_writecount--; 213 error = VOP_CLOSE(vp, flags, cred, p); 214 vrele(vp); 215 return (error); 216 } 217 218 /* 219 * Package up an I/O request on a vnode into a uio and do it. 220 */ 221 int 222 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 223 enum uio_rw rw; 224 struct vnode *vp; 225 caddr_t base; 226 int len; 227 off_t offset; 228 enum uio_seg segflg; 229 int ioflg; 230 struct ucred *cred; 231 int *aresid; 232 struct proc *p; 233 { 234 struct uio auio; 235 struct iovec aiov; 236 int error; 237 238 if ((ioflg & IO_NODELOCKED) == 0) 239 VOP_LOCK(vp); 240 auio.uio_iov = &aiov; 241 auio.uio_iovcnt = 1; 242 aiov.iov_base = base; 243 aiov.iov_len = len; 244 auio.uio_resid = len; 245 auio.uio_offset = offset; 246 auio.uio_segflg = segflg; 247 auio.uio_rw = rw; 248 auio.uio_procp = p; 249 if (rw == UIO_READ) { 250 error = VOP_READ(vp, &auio, ioflg, cred); 251 } else { 252 error = VOP_WRITE(vp, &auio, ioflg, cred); 253 } 254 if (aresid) 255 *aresid = auio.uio_resid; 256 else 257 if (auio.uio_resid && error == 0) 258 error = EIO; 259 if ((ioflg & IO_NODELOCKED) == 0) 260 VOP_UNLOCK(vp); 261 return (error); 262 } 263 264 int 265 vn_readdir(fp, buf, segflg, count, done, p, cookies, ncookies) 266 struct file *fp; 267 char *buf; 268 int segflg, *done, ncookies; 269 u_int count; 270 struct proc *p; 271 off_t *cookies; 272 { 273 struct vnode *vp = (struct vnode *)fp->f_data; 274 struct iovec aiov; 275 struct uio auio; 276 int error, eofflag; 277 278 unionread: 279 if (vp->v_type != VDIR) 280 return (EINVAL); 281 aiov.iov_base = buf; 282 aiov.iov_len = count; 283 auio.uio_iov = &aiov; 284 auio.uio_iovcnt = 1; 285 auio.uio_rw = UIO_READ; 286 auio.uio_segflg = segflg; 287 auio.uio_procp = p; 288 auio.uio_resid = count; 289 VOP_LOCK(vp); 290 auio.uio_offset = fp->f_offset; 291 error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, (off_t *)cookies, 292 ncookies); 293 fp->f_offset = auio.uio_offset; 294 VOP_UNLOCK(vp); 295 if (error) 296 return (error); 297 298 #ifdef UNION 299 { 300 extern int (**union_vnodeop_p) __P((void *)); 301 extern struct vnode *union_dircache __P((struct vnode *)); 302 303 if (count == auio.uio_resid && (vp->v_op == union_vnodeop_p)) { 304 struct vnode *lvp; 305 306 lvp = union_dircache(vp); 307 if (lvp != NULLVP) { 308 struct vattr va; 309 310 /* 311 * If the directory is opaque, 312 * then don't show lower entries 313 */ 314 error = VOP_GETATTR(vp, &va, fp->f_cred, p); 315 if (va.va_flags & OPAQUE) { 316 vput(lvp); 317 lvp = NULL; 318 } 319 } 320 321 if (lvp != NULLVP) { 322 error = VOP_OPEN(lvp, FREAD, fp->f_cred, p); 323 VOP_UNLOCK(lvp); 324 325 if (error) { 326 vrele(lvp); 327 return (error); 328 } 329 fp->f_data = (caddr_t) lvp; 330 fp->f_offset = 0; 331 error = vn_close(vp, FREAD, fp->f_cred, p); 332 if (error) 333 return (error); 334 vp = lvp; 335 goto unionread; 336 } 337 } 338 } 339 #endif /* UNION */ 340 341 if (count == auio.uio_resid && (vp->v_flag & VROOT) && 342 (vp->v_mount->mnt_flag & MNT_UNION)) { 343 struct vnode *tvp = vp; 344 vp = vp->v_mount->mnt_vnodecovered; 345 VREF(vp); 346 fp->f_data = (caddr_t) vp; 347 fp->f_offset = 0; 348 vrele(tvp); 349 goto unionread; 350 } 351 *done = count - auio.uio_resid; 352 return error; 353 } 354 355 /* 356 * File table vnode read routine. 357 */ 358 int 359 vn_read(fp, uio, cred) 360 struct file *fp; 361 struct uio *uio; 362 struct ucred *cred; 363 { 364 register struct vnode *vp = (struct vnode *)fp->f_data; 365 int count, error; 366 367 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_READ); 368 VOP_LOCK(vp); 369 uio->uio_offset = fp->f_offset; 370 count = uio->uio_resid; 371 error = VOP_READ(vp, uio, (fp->f_flag & FNONBLOCK) ? IO_NDELAY : 0, 372 cred); 373 fp->f_offset += count - uio->uio_resid; 374 VOP_UNLOCK(vp); 375 return (error); 376 } 377 378 /* 379 * File table vnode write routine. 380 */ 381 int 382 vn_write(fp, uio, cred) 383 struct file *fp; 384 struct uio *uio; 385 struct ucred *cred; 386 { 387 register 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 VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE); 398 VOP_LOCK(vp); 399 uio->uio_offset = fp->f_offset; 400 count = uio->uio_resid; 401 error = VOP_WRITE(vp, uio, ioflag, cred); 402 if (ioflag & IO_APPEND) 403 fp->f_offset = uio->uio_offset; 404 else 405 fp->f_offset += count - uio->uio_resid; 406 VOP_UNLOCK(vp); 407 return (error); 408 } 409 410 /* 411 * File table vnode stat routine. 412 */ 413 int 414 vn_stat(vp, sb, p) 415 struct vnode *vp; 416 register struct stat *sb; 417 struct proc *p; 418 { 419 struct vattr va; 420 int error; 421 u_short mode; 422 423 error = VOP_GETATTR(vp, &va, p->p_ucred, p); 424 if (error) 425 return (error); 426 /* 427 * Copy from vattr table 428 */ 429 sb->st_dev = va.va_fsid; 430 sb->st_ino = va.va_fileid; 431 mode = va.va_mode; 432 switch (vp->v_type) { 433 case VREG: 434 mode |= S_IFREG; 435 break; 436 case VDIR: 437 mode |= S_IFDIR; 438 break; 439 case VBLK: 440 mode |= S_IFBLK; 441 break; 442 case VCHR: 443 mode |= S_IFCHR; 444 break; 445 case VLNK: 446 mode |= S_IFLNK; 447 break; 448 case VSOCK: 449 mode |= S_IFSOCK; 450 break; 451 case VFIFO: 452 mode |= S_IFIFO; 453 break; 454 default: 455 return (EBADF); 456 }; 457 sb->st_mode = mode; 458 sb->st_nlink = va.va_nlink; 459 sb->st_uid = va.va_uid; 460 sb->st_gid = va.va_gid; 461 sb->st_rdev = va.va_rdev; 462 sb->st_size = va.va_size; 463 sb->st_atimespec = va.va_atime; 464 sb->st_mtimespec = va.va_mtime; 465 sb->st_ctimespec = va.va_ctime; 466 sb->st_blksize = va.va_blocksize; 467 sb->st_flags = va.va_flags; 468 sb->st_gen = 0; 469 sb->st_blocks = va.va_bytes / S_BLKSIZE; 470 return (0); 471 } 472 473 /* 474 * File table vnode ioctl routine. 475 */ 476 int 477 vn_ioctl(fp, com, data, p) 478 struct file *fp; 479 u_long com; 480 caddr_t data; 481 struct proc *p; 482 { 483 register struct vnode *vp = ((struct vnode *)fp->f_data); 484 struct vattr vattr; 485 int error; 486 487 switch (vp->v_type) { 488 489 case VREG: 490 case VDIR: 491 if (com == FIONREAD) { 492 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 493 if (error) 494 return (error); 495 *(int *)data = vattr.va_size - fp->f_offset; 496 return (0); 497 } 498 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 499 return (0); /* XXX */ 500 /* fall into ... */ 501 502 default: 503 return (ENOTTY); 504 505 case VFIFO: 506 case VCHR: 507 case VBLK: 508 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 509 if (error == 0 && com == TIOCSCTTY) { 510 if (p->p_session->s_ttyvp) 511 vrele(p->p_session->s_ttyvp); 512 p->p_session->s_ttyvp = vp; 513 VREF(vp); 514 } 515 return (error); 516 } 517 } 518 519 /* 520 * File table vnode poll routine. 521 */ 522 int 523 vn_poll(fp, events, p) 524 struct file *fp; 525 int events; 526 struct proc *p; 527 { 528 529 return (VOP_POLL(((struct vnode *)fp->f_data), events, p)); 530 } 531 532 /* 533 * File table vnode close routine. 534 */ 535 int 536 vn_closefile(fp, p) 537 struct file *fp; 538 struct proc *p; 539 { 540 541 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 542 fp->f_cred, p)); 543 } 544
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