1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 39 * $Id: vfs_vnops.c,v 1.31 1997/03/07 07:42:41 gpalmer Exp $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/kernel.h> 45 #include <sys/file.h> 46 #include <sys/stat.h> 47 #include <sys/buf.h> 48 #include <sys/proc.h> 49 #include <sys/mount.h> 50 #include <sys/namei.h> 51 #include <sys/vnode.h> 52 #include <sys/ioctl.h> 53 54 #include <vm/vm.h> 55 #include <vm/vm_param.h> 56 #include <vm/vm_object.h> 57 #include <vm/vnode_pager.h> 58 59 static int vn_closefile __P((struct file *fp, struct proc *p)); 60 static int vn_ioctl __P((struct file *fp, int com, caddr_t data, 61 struct proc *p)); 62 static int vn_read __P((struct file *fp, struct uio *uio, 63 struct ucred *cred)); 64 static int vn_select __P((struct file *fp, int which, struct proc *p)); 65 static int vn_write __P((struct file *fp, struct uio *uio, 66 struct ucred *cred)); 67 68 struct fileops vnops = 69 { vn_read, vn_write, vn_ioctl, vn_select, vn_closefile }; 70 71 /* 72 * Common code for vnode open operations. 73 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 74 */ 75 int 76 vn_open(ndp, fmode, cmode) 77 register struct nameidata *ndp; 78 int fmode, cmode; 79 { 80 register struct vnode *vp; 81 register struct proc *p = ndp->ni_cnd.cn_proc; 82 register struct ucred *cred = p->p_ucred; 83 struct vattr vat; 84 struct vattr *vap = &vat; 85 int error; 86 87 if (fmode & O_CREAT) { 88 ndp->ni_cnd.cn_nameiop = CREATE; 89 ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF; 90 if ((fmode & O_EXCL) == 0) 91 ndp->ni_cnd.cn_flags |= FOLLOW; 92 error = namei(ndp); 93 if (error) 94 return (error); 95 if (ndp->ni_vp == NULL) { 96 VATTR_NULL(vap); 97 vap->va_type = VREG; 98 vap->va_mode = cmode; 99 if (fmode & O_EXCL) 100 vap->va_vaflags |= VA_EXCLUSIVE; 101 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 102 if (error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 103 &ndp->ni_cnd, vap)) 104 return (error); 105 fmode &= ~O_TRUNC; 106 vp = ndp->ni_vp; 107 } else { 108 VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd); 109 if (ndp->ni_dvp == ndp->ni_vp) 110 vrele(ndp->ni_dvp); 111 else 112 vput(ndp->ni_dvp); 113 ndp->ni_dvp = NULL; 114 vp = ndp->ni_vp; 115 if (fmode & O_EXCL) { 116 error = EEXIST; 117 goto bad; 118 } 119 fmode &= ~O_CREAT; 120 } 121 } else { 122 ndp->ni_cnd.cn_nameiop = LOOKUP; 123 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF; 124 error = namei(ndp); 125 if (error) 126 return (error); 127 vp = ndp->ni_vp; 128 } 129 if (vp->v_type == VSOCK) { 130 error = EOPNOTSUPP; 131 goto bad; 132 } 133 if ((fmode & O_CREAT) == 0) { 134 if (fmode & FREAD) { 135 error = VOP_ACCESS(vp, VREAD, cred, p); 136 if (error) 137 goto bad; 138 } 139 if (fmode & (FWRITE | O_TRUNC)) { 140 if (vp->v_type == VDIR) { 141 error = EISDIR; 142 goto bad; 143 } 144 error = vn_writechk(vp); 145 if (error) 146 goto bad; 147 error = VOP_ACCESS(vp, VWRITE, cred, p); 148 if (error) 149 goto bad; 150 } 151 } 152 if (fmode & O_TRUNC) { 153 VOP_UNLOCK(vp, 0, p); /* XXX */ 154 VOP_LEASE(vp, p, cred, LEASE_WRITE); 155 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); /* XXX */ 156 VATTR_NULL(vap); 157 vap->va_size = 0; 158 error = VOP_SETATTR(vp, vap, cred, p); 159 if (error) 160 goto bad; 161 } 162 error = VOP_OPEN(vp, fmode, cred, p); 163 if (error) 164 goto bad; 165 /* 166 * Make sure that a VM object is created for VMIO support. 167 */ 168 if (vp->v_type == VREG) { 169 if ((error = vfs_object_create(vp, p, cred, 1)) != 0) 170 goto bad; 171 } 172 173 if (fmode & FWRITE) 174 vp->v_writecount++; 175 return (0); 176 bad: 177 vput(vp); 178 return (error); 179 } 180 181 /* 182 * Check for write permissions on the specified vnode. 183 * Prototype text segments cannot be written. 184 */ 185 int 186 vn_writechk(vp) 187 register struct vnode *vp; 188 { 189 190 /* 191 * If there's shared text associated with 192 * the vnode, try to free it up once. If 193 * we fail, we can't allow writing. 194 */ 195 if (vp->v_flag & VTEXT) 196 return (ETXTBSY); 197 return (0); 198 } 199 200 /* 201 * Vnode close call 202 */ 203 int 204 vn_close(vp, flags, cred, p) 205 register struct vnode *vp; 206 int flags; 207 struct ucred *cred; 208 struct proc *p; 209 { 210 int error; 211 212 if (flags & FWRITE) 213 vp->v_writecount--; 214 error = VOP_CLOSE(vp, flags, cred, p); 215 vrele(vp); 216 return (error); 217 } 218 219 /* 220 * Package up an I/O request on a vnode into a uio and do it. 221 */ 222 int 223 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 224 enum uio_rw rw; 225 struct vnode *vp; 226 caddr_t base; 227 int len; 228 off_t offset; 229 enum uio_seg segflg; 230 int ioflg; 231 struct ucred *cred; 232 int *aresid; 233 struct proc *p; 234 { 235 struct uio auio; 236 struct iovec aiov; 237 int error; 238 239 if ((ioflg & IO_NODELOCKED) == 0) 240 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 241 auio.uio_iov = &aiov; 242 auio.uio_iovcnt = 1; 243 aiov.iov_base = base; 244 aiov.iov_len = len; 245 auio.uio_resid = len; 246 auio.uio_offset = offset; 247 auio.uio_segflg = segflg; 248 auio.uio_rw = rw; 249 auio.uio_procp = p; 250 if (rw == UIO_READ) { 251 error = VOP_READ(vp, &auio, ioflg, cred); 252 } else { 253 error = VOP_WRITE(vp, &auio, ioflg, cred); 254 } 255 if (aresid) 256 *aresid = auio.uio_resid; 257 else 258 if (auio.uio_resid && error == 0) 259 error = EIO; 260 if ((ioflg & IO_NODELOCKED) == 0) 261 VOP_UNLOCK(vp, 0, p); 262 return (error); 263 } 264 265 /* 266 * File table vnode read routine. 267 */ 268 static int 269 vn_read(fp, uio, cred) 270 struct file *fp; 271 struct uio *uio; 272 struct ucred *cred; 273 { 274 struct vnode *vp = (struct vnode *)fp->f_data; 275 struct proc *p = uio->uio_procp; 276 int count, error; 277 int flag, seq; 278 279 VOP_LEASE(vp, p, cred, LEASE_READ); 280 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 281 uio->uio_offset = fp->f_offset; 282 count = uio->uio_resid; 283 flag = 0; 284 if (fp->f_flag & FNONBLOCK) 285 flag |= IO_NDELAY; 286 287 /* 288 * Sequential read heuristic. 289 * If we have been doing sequential input, 290 * a rewind operation doesn't turn off 291 * sequential input mode. 292 */ 293 if (((fp->f_offset == 0) && (fp->f_seqcount > 0)) || 294 (fp->f_offset == fp->f_nextread)) { 295 int tmpseq = fp->f_seqcount; 296 /* 297 * XXX we assume that the filesystem block size is 298 * the default. Not true, but still gives us a pretty 299 * good indicator of how sequential the read operations 300 * are. 301 */ 302 tmpseq += ((count + BKVASIZE - 1) / BKVASIZE); 303 if (tmpseq >= CHAR_MAX) 304 tmpseq = CHAR_MAX; 305 fp->f_seqcount = tmpseq; 306 flag |= (fp->f_seqcount << 16); 307 } else { 308 if (fp->f_seqcount > 1) 309 fp->f_seqcount = 1; 310 else 311 fp->f_seqcount = 0; 312 } 313 314 error = VOP_READ(vp, uio, flag, cred); 315 fp->f_offset += count - uio->uio_resid; 316 fp->f_nextread = fp->f_offset; 317 VOP_UNLOCK(vp, 0, p); 318 return (error); 319 } 320 321 /* 322 * File table vnode write routine. 323 */ 324 static int 325 vn_write(fp, uio, cred) 326 struct file *fp; 327 struct uio *uio; 328 struct ucred *cred; 329 { 330 struct vnode *vp = (struct vnode *)fp->f_data; 331 struct proc *p = uio->uio_procp; 332 int count, error, ioflag = IO_UNIT; 333 334 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 335 ioflag |= IO_APPEND; 336 if (fp->f_flag & FNONBLOCK) 337 ioflag |= IO_NDELAY; 338 if ((fp->f_flag & O_FSYNC) || 339 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 340 ioflag |= IO_SYNC; 341 VOP_LEASE(vp, p, cred, LEASE_WRITE); 342 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 343 uio->uio_offset = fp->f_offset; 344 count = uio->uio_resid; 345 error = VOP_WRITE(vp, uio, ioflag, cred); 346 if (ioflag & IO_APPEND) 347 fp->f_offset = uio->uio_offset; 348 else 349 fp->f_offset += count - uio->uio_resid; 350 VOP_UNLOCK(vp, 0, p); 351 return (error); 352 } 353 354 /* 355 * File table vnode stat routine. 356 */ 357 int 358 vn_stat(vp, sb, p) 359 struct vnode *vp; 360 register struct stat *sb; 361 struct proc *p; 362 { 363 struct vattr vattr; 364 register struct vattr *vap; 365 int error; 366 u_short mode; 367 368 vap = &vattr; 369 error = VOP_GETATTR(vp, vap, p->p_ucred, p); 370 if (error) 371 return (error); 372 /* 373 * Copy from vattr table 374 */ 375 sb->st_dev = vap->va_fsid; 376 sb->st_ino = vap->va_fileid; 377 mode = vap->va_mode; 378 switch (vp->v_type) { 379 case VREG: 380 mode |= S_IFREG; 381 break; 382 case VDIR: 383 mode |= S_IFDIR; 384 break; 385 case VBLK: 386 mode |= S_IFBLK; 387 break; 388 case VCHR: 389 mode |= S_IFCHR; 390 break; 391 case VLNK: 392 mode |= S_IFLNK; 393 break; 394 case VSOCK: 395 mode |= S_IFSOCK; 396 break; 397 case VFIFO: 398 mode |= S_IFIFO; 399 break; 400 default: 401 return (EBADF); 402 }; 403 sb->st_mode = mode; 404 sb->st_nlink = vap->va_nlink; 405 sb->st_uid = vap->va_uid; 406 sb->st_gid = vap->va_gid; 407 sb->st_rdev = vap->va_rdev; 408 sb->st_size = vap->va_size; 409 sb->st_atimespec = vap->va_atime; 410 sb->st_mtimespec = vap->va_mtime; 411 sb->st_ctimespec = vap->va_ctime; 412 sb->st_blksize = vap->va_blocksize; 413 sb->st_flags = vap->va_flags; 414 if (p->p_ucred->cr_uid != 0) 415 sb->st_gen = 0; 416 else 417 sb->st_gen = vap->va_gen; 418 419 #if (S_BLKSIZE == 512) 420 /* Optimize this case */ 421 sb->st_blocks = vap->va_bytes >> 9; 422 #else 423 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 424 #endif 425 return (0); 426 } 427 428 /* 429 * File table vnode ioctl routine. 430 */ 431 static int 432 vn_ioctl(fp, com, data, p) 433 struct file *fp; 434 int com; 435 caddr_t data; 436 struct proc *p; 437 { 438 register struct vnode *vp = ((struct vnode *)fp->f_data); 439 struct vattr vattr; 440 int error; 441 442 switch (vp->v_type) { 443 444 case VREG: 445 case VDIR: 446 if (com == FIONREAD) { 447 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 448 if (error) 449 return (error); 450 *(int *)data = vattr.va_size - fp->f_offset; 451 return (0); 452 } 453 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 454 return (0); /* XXX */ 455 /* fall into ... */ 456 457 default: 458 return (ENOTTY); 459 460 case VFIFO: 461 case VCHR: 462 case VBLK: 463 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 464 if (error == 0 && com == TIOCSCTTY) { 465 466 /* Do nothing if reassigning same control tty */ 467 if (p->p_session->s_ttyvp == vp) 468 return (0); 469 470 /* Get rid of reference to old control tty */ 471 if (p->p_session->s_ttyvp) 472 vrele(p->p_session->s_ttyvp); 473 474 p->p_session->s_ttyvp = vp; 475 VREF(vp); 476 } 477 return (error); 478 } 479 } 480 481 /* 482 * File table vnode select routine. 483 */ 484 static int 485 vn_select(fp, which, p) 486 struct file *fp; 487 int which; 488 struct proc *p; 489 { 490 491 return (VOP_SELECT(((struct vnode *)fp->f_data), which, fp->f_flag, 492 fp->f_cred, p)); 493 } 494 495 /* 496 * File table vnode close routine. 497 */ 498 static int 499 vn_closefile(fp, p) 500 struct file *fp; 501 struct proc *p; 502 { 503 504 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 505 fp->f_cred, p)); 506 } 507 508 /* 509 * Check that the vnode is still valid, and if so 510 * acquire requested lock. 511 */ 512 int 513 vn_lock(vp, flags, p) 514 struct vnode *vp; 515 int flags; 516 struct proc *p; 517 { 518 int error; 519 520 do { 521 if ((flags & LK_INTERLOCK) == 0) { 522 simple_lock(&vp->v_interlock); 523 } 524 if (vp->v_flag & VXLOCK) { 525 vp->v_flag |= VXWANT; 526 simple_unlock(&vp->v_interlock); 527 tsleep((caddr_t)vp, PINOD, "vn_lock", 0); 528 error = ENOENT; 529 } else { 530 error = VOP_LOCK(vp, flags | LK_INTERLOCK, p); 531 if (error == 0) 532 return (error); 533 } 534 flags &= ~LK_INTERLOCK; 535 } while (flags & LK_RETRY); 536 return (error); 537 } 538