Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_vnops.c
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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 * $FreeBSD$ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/fcntl.h> 45 #include <sys/file.h> 46 #include <sys/stat.h> 47 #include <sys/proc.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/vnode.h> 51 #include <sys/filio.h> 52 #include <sys/ttycom.h> 53 54 static int vn_closefile __P((struct file *fp, struct proc *p)); 55 static int vn_ioctl __P((struct file *fp, u_long com, caddr_t data, 56 struct proc *p)); 57 static int vn_read __P((struct file *fp, struct uio *uio, 58 struct ucred *cred, int flags)); 59 static int vn_poll __P((struct file *fp, int events, struct ucred *cred, 60 struct proc *p)); 61 static int vn_write __P((struct file *fp, struct uio *uio, 62 struct ucred *cred, int flags)); 63 64 struct fileops vnops = 65 { vn_read, vn_write, vn_ioctl, vn_poll, vn_closefile }; 66 67 /* 68 * Common code for vnode open operations. 69 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 70 */ 71 int 72 vn_open(ndp, fmode, cmode) 73 register struct nameidata *ndp; 74 int fmode, cmode; 75 { 76 register struct vnode *vp; 77 register struct proc *p = ndp->ni_cnd.cn_proc; 78 register struct ucred *cred = p->p_ucred; 79 struct vattr vat; 80 struct vattr *vap = &vat; 81 int mode, 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 && (fmode & O_NOFOLLOW) == 0) 87 ndp->ni_cnd.cn_flags |= FOLLOW; 88 error = namei(ndp); 89 if (error) 90 return (error); 91 if (ndp->ni_vp == NULL) { 92 VATTR_NULL(vap); 93 vap->va_type = VREG; 94 vap->va_mode = cmode; 95 if (fmode & O_EXCL) 96 vap->va_vaflags |= VA_EXCLUSIVE; 97 VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE); 98 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 99 &ndp->ni_cnd, vap); 100 vput(ndp->ni_dvp); 101 if (error) 102 return (error); 103 ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "create"); 104 ASSERT_VOP_LOCKED(ndp->ni_vp, "create"); 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 = 124 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 125 error = namei(ndp); 126 if (error) 127 return (error); 128 vp = ndp->ni_vp; 129 } 130 if (vp->v_type == VLNK) { 131 error = EMLINK; 132 goto bad; 133 } 134 if (vp->v_type == VSOCK) { 135 error = EOPNOTSUPP; 136 goto bad; 137 } 138 if ((fmode & O_CREAT) == 0) { 139 mode = 0; 140 if (fmode & (FWRITE | O_TRUNC)) { 141 if (vp->v_type == VDIR) { 142 error = EISDIR; 143 goto bad; 144 } 145 error = vn_writechk(vp); 146 if (error) 147 goto bad; 148 mode |= VWRITE; 149 } 150 if (fmode & FREAD) 151 mode |= VREAD; 152 if (mode) { 153 error = VOP_ACCESS(vp, mode, cred, p); 154 if (error) 155 goto bad; 156 } 157 } 158 if (fmode & O_TRUNC) { 159 VOP_UNLOCK(vp, 0, p); /* XXX */ 160 VOP_LEASE(vp, p, cred, LEASE_WRITE); 161 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); /* XXX */ 162 VATTR_NULL(vap); 163 vap->va_size = 0; 164 error = VOP_SETATTR(vp, vap, cred, p); 165 if (error) 166 goto bad; 167 } 168 error = VOP_OPEN(vp, fmode, cred, p); 169 if (error) 170 goto bad; 171 /* 172 * Make sure that a VM object is created for VMIO support. 173 */ 174 if (vp->v_type == VREG) { 175 if ((error = vfs_object_create(vp, p, cred)) != 0) 176 goto bad; 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(vp) 193 register struct vnode *vp; 194 { 195 196 /* 197 * If there's shared text associated with 198 * the vnode, try to free it up once. If 199 * we fail, we can't allow writing. 200 */ 201 if (vp->v_flag & VTEXT) 202 return (ETXTBSY); 203 return (0); 204 } 205 206 /* 207 * Vnode close call 208 */ 209 int 210 vn_close(vp, flags, cred, p) 211 register struct vnode *vp; 212 int flags; 213 struct ucred *cred; 214 struct proc *p; 215 { 216 int error; 217 218 if (flags & FWRITE) 219 vp->v_writecount--; 220 error = VOP_CLOSE(vp, flags, cred, p); 221 vrele(vp); 222 return (error); 223 } 224 225 /* 226 * Package up an I/O request on a vnode into a uio and do it. 227 */ 228 int 229 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p) 230 enum uio_rw rw; 231 struct vnode *vp; 232 caddr_t base; 233 int len; 234 off_t offset; 235 enum uio_seg segflg; 236 int ioflg; 237 struct ucred *cred; 238 int *aresid; 239 struct proc *p; 240 { 241 struct uio auio; 242 struct iovec aiov; 243 int error; 244 245 if ((ioflg & IO_NODELOCKED) == 0) 246 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 247 auio.uio_iov = &aiov; 248 auio.uio_iovcnt = 1; 249 aiov.iov_base = base; 250 aiov.iov_len = len; 251 auio.uio_resid = len; 252 auio.uio_offset = offset; 253 auio.uio_segflg = segflg; 254 auio.uio_rw = rw; 255 auio.uio_procp = p; 256 if (rw == UIO_READ) { 257 error = VOP_READ(vp, &auio, ioflg, cred); 258 } else { 259 error = VOP_WRITE(vp, &auio, ioflg, cred); 260 } 261 if (aresid) 262 *aresid = auio.uio_resid; 263 else 264 if (auio.uio_resid && error == 0) 265 error = EIO; 266 if ((ioflg & IO_NODELOCKED) == 0) 267 VOP_UNLOCK(vp, 0, p); 268 return (error); 269 } 270 271 /* 272 * File table vnode read routine. 273 */ 274 static int 275 vn_read(fp, uio, cred, flags) 276 struct file *fp; 277 struct uio *uio; 278 struct ucred *cred; 279 int flags; 280 { 281 struct vnode *vp = (struct vnode *)fp->f_data; 282 struct proc *p = uio->uio_procp; 283 int error, ioflag; 284 285 ioflag = 0; 286 if (fp->f_flag & FNONBLOCK) 287 ioflag |= IO_NDELAY; 288 VOP_LEASE(vp, p, cred, LEASE_READ); 289 vn_lock(vp, LK_SHARED | LK_NOPAUSE | LK_RETRY, p); 290 if ((flags & FOF_OFFSET) == 0) 291 uio->uio_offset = fp->f_offset; 292 293 /* 294 * Sequential read heuristic. 295 * If we have been doing sequential input, 296 * a rewind operation doesn't turn off 297 * sequential input mode. 298 */ 299 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 300 uio->uio_offset == fp->f_nextread) { 301 int tmpseq = fp->f_seqcount; 302 /* 303 * XXX we assume that the filesystem block size is 304 * the default. Not true, but still gives us a pretty 305 * good indicator of how sequential the read operations 306 * are. 307 */ 308 tmpseq += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE; 309 if (tmpseq >= 127) 310 tmpseq = 127; 311 fp->f_seqcount = tmpseq; 312 ioflag |= fp->f_seqcount << 16; 313 } else { 314 if (fp->f_seqcount > 1) 315 fp->f_seqcount = 1; 316 else 317 fp->f_seqcount = 0; 318 } 319 error = VOP_READ(vp, uio, ioflag, cred); 320 if ((flags & FOF_OFFSET) == 0) 321 fp->f_offset = uio->uio_offset; 322 fp->f_nextread = uio->uio_offset; 323 VOP_UNLOCK(vp, 0, p); 324 return (error); 325 } 326 327 /* 328 * File table vnode write routine. 329 */ 330 static int 331 vn_write(fp, uio, cred, flags) 332 struct file *fp; 333 struct uio *uio; 334 struct ucred *cred; 335 int flags; 336 { 337 struct vnode *vp = (struct vnode *)fp->f_data; 338 struct proc *p = uio->uio_procp; 339 int error, ioflag; 340 341 ioflag = IO_UNIT; 342 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 343 ioflag |= IO_APPEND; 344 if (fp->f_flag & FNONBLOCK) 345 ioflag |= IO_NDELAY; 346 if ((fp->f_flag & O_FSYNC) || 347 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 348 ioflag |= IO_SYNC; 349 VOP_LEASE(vp, p, cred, LEASE_WRITE); 350 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 351 if ((flags & FOF_OFFSET) == 0) 352 uio->uio_offset = fp->f_offset; 353 error = VOP_WRITE(vp, uio, ioflag, cred); 354 if ((flags & FOF_OFFSET) == 0) 355 fp->f_offset = uio->uio_offset; 356 VOP_UNLOCK(vp, 0, p); 357 return (error); 358 } 359 360 /* 361 * File table vnode stat routine. 362 */ 363 int 364 vn_stat(vp, sb, p) 365 struct vnode *vp; 366 register struct stat *sb; 367 struct proc *p; 368 { 369 struct vattr vattr; 370 register struct vattr *vap; 371 int error; 372 u_short mode; 373 374 vap = &vattr; 375 error = VOP_GETATTR(vp, vap, p->p_ucred, p); 376 if (error) 377 return (error); 378 379 /* 380 * Zero the spare stat fields 381 */ 382 sb->st_lspare = 0; 383 sb->st_qspare[0] = 0; 384 sb->st_qspare[1] = 0; 385 386 /* 387 * Copy from vattr table 388 */ 389 sb->st_dev = vap->va_fsid; 390 sb->st_ino = vap->va_fileid; 391 mode = vap->va_mode; 392 switch (vap->va_type) { 393 case VREG: 394 mode |= S_IFREG; 395 break; 396 case VDIR: 397 mode |= S_IFDIR; 398 break; 399 case VBLK: 400 mode |= S_IFBLK; 401 break; 402 case VCHR: 403 mode |= S_IFCHR; 404 break; 405 case VLNK: 406 mode |= S_IFLNK; 407 /* This is a cosmetic change, symlinks do not have a mode. */ 408 if (vp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) 409 sb->st_mode &= ~ACCESSPERMS; /* 0000 */ 410 else 411 sb->st_mode |= ACCESSPERMS; /* 0777 */ 412 break; 413 case VSOCK: 414 mode |= S_IFSOCK; 415 break; 416 case VFIFO: 417 mode |= S_IFIFO; 418 break; 419 default: 420 return (EBADF); 421 }; 422 sb->st_mode = mode; 423 sb->st_nlink = vap->va_nlink; 424 sb->st_uid = vap->va_uid; 425 sb->st_gid = vap->va_gid; 426 sb->st_rdev = vap->va_rdev; 427 sb->st_size = vap->va_size; 428 sb->st_atimespec = vap->va_atime; 429 sb->st_mtimespec = vap->va_mtime; 430 sb->st_ctimespec = vap->va_ctime; 431 sb->st_blksize = vap->va_blocksize; 432 sb->st_flags = vap->va_flags; 433 if (p->p_ucred->cr_uid != 0) 434 sb->st_gen = 0; 435 else 436 sb->st_gen = vap->va_gen; 437 438 #if (S_BLKSIZE == 512) 439 /* Optimize this case */ 440 sb->st_blocks = vap->va_bytes >> 9; 441 #else 442 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 443 #endif 444 return (0); 445 } 446 447 /* 448 * File table vnode ioctl routine. 449 */ 450 static int 451 vn_ioctl(fp, com, data, p) 452 struct file *fp; 453 u_long com; 454 caddr_t data; 455 struct proc *p; 456 { 457 register struct vnode *vp = ((struct vnode *)fp->f_data); 458 struct vattr vattr; 459 int error; 460 461 switch (vp->v_type) { 462 463 case VREG: 464 case VDIR: 465 if (com == FIONREAD) { 466 error = VOP_GETATTR(vp, &vattr, p->p_ucred, p); 467 if (error) 468 return (error); 469 *(int *)data = vattr.va_size - fp->f_offset; 470 return (0); 471 } 472 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 473 return (0); /* XXX */ 474 /* fall into ... */ 475 476 default: 477 #if 0 478 return (ENOTTY); 479 #endif 480 case VFIFO: 481 case VCHR: 482 case VBLK: 483 error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p); 484 if (error == 0 && com == TIOCSCTTY) { 485 486 /* Do nothing if reassigning same control tty */ 487 if (p->p_session->s_ttyvp == vp) 488 return (0); 489 490 /* Get rid of reference to old control tty */ 491 if (p->p_session->s_ttyvp) 492 vrele(p->p_session->s_ttyvp); 493 494 p->p_session->s_ttyvp = vp; 495 VREF(vp); 496 } 497 return (error); 498 } 499 } 500 501 /* 502 * File table vnode poll routine. 503 */ 504 static int 505 vn_poll(fp, events, cred, p) 506 struct file *fp; 507 int events; 508 struct ucred *cred; 509 struct proc *p; 510 { 511 512 return (VOP_POLL(((struct vnode *)fp->f_data), events, cred, p)); 513 } 514 515 /* 516 * Check that the vnode is still valid, and if so 517 * acquire requested lock. 518 */ 519 int 520 #ifndef DEBUG_LOCKS 521 vn_lock(vp, flags, p) 522 #else 523 debug_vn_lock(vp, flags, p, filename, line) 524 #endif 525 struct vnode *vp; 526 int flags; 527 struct proc *p; 528 #ifdef DEBUG_LOCKS 529 const char *filename; 530 int line; 531 #endif 532 { 533 int error; 534 535 do { 536 if ((flags & LK_INTERLOCK) == 0) 537 simple_lock(&vp->v_interlock); 538 if (vp->v_flag & VXLOCK) { 539 vp->v_flag |= VXWANT; 540 simple_unlock(&vp->v_interlock); 541 tsleep((caddr_t)vp, PINOD, "vn_lock", 0); 542 error = ENOENT; 543 } else { 544 #ifdef DEBUG_LOCKS 545 vp->filename = filename; 546 vp->line = line; 547 #endif 548 error = VOP_LOCK(vp, 549 flags | LK_NOPAUSE | LK_INTERLOCK, p); 550 if (error == 0) 551 return (error); 552 } 553 flags &= ~LK_INTERLOCK; 554 } while (flags & LK_RETRY); 555 return (error); 556 } 557 558 /* 559 * File table vnode close routine. 560 */ 561 static int 562 vn_closefile(fp, p) 563 struct file *fp; 564 struct proc *p; 565 { 566 567 return (vn_close(((struct vnode *)fp->f_data), fp->f_flag, 568 fp->f_cred, p)); 569 }
Cache object: a3d8b95e73903ec9f0db89b663716c33
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