1 /* 2 * Copyright (c) 1982, 1986, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)vfs_vnops.c 7.24 (Berkeley) 08/22/90 8 */ 9 10 #include "param.h" 11 #include "systm.h" 12 #include "user.h" 13 #include "kernel.h" 14 #include "file.h" 15 #include "stat.h" 16 #include "buf.h" 17 #include "proc.h" 18 #include "uio.h" 19 #include "socket.h" 20 #include "socketvar.h" 21 #include "mount.h" 22 #include "vnode.h" 23 #include "ioctl.h" 24 #include "tty.h" 25 26 int vn_read(), vn_write(), vn_ioctl(), vn_select(), vn_close(); 27 struct fileops vnops = 28 { vn_read, vn_write, vn_ioctl, vn_select, vn_close }; 29 30 /* 31 * Common code for vnode open operations. 32 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 33 */ 34 vn_open(ndp, fmode, cmode) 35 register struct nameidata *ndp; 36 int fmode, cmode; 37 { 38 register struct vnode *vp; 39 struct vattr vat; 40 struct vattr *vap = &vat; 41 int error; 42 43 if (fmode & FCREAT) { 44 ndp->ni_nameiop = CREATE | LOCKPARENT | LOCKLEAF; 45 if ((fmode & FEXCL) == 0) 46 ndp->ni_nameiop |= FOLLOW; 47 if (error = namei(ndp)) 48 return (error); 49 if (ndp->ni_vp == NULL) { 50 VATTR_NULL(vap); 51 vap->va_type = VREG; 52 vap->va_mode = cmode; 53 if (error = VOP_CREATE(ndp, vap)) 54 return (error); 55 fmode &= ~FTRUNC; 56 vp = ndp->ni_vp; 57 } else { 58 if (ndp->ni_dvp == ndp->ni_vp) 59 vrele(ndp->ni_dvp); 60 else 61 vput(ndp->ni_dvp); 62 ndp->ni_dvp = NULL; 63 vp = ndp->ni_vp; 64 if (fmode & FEXCL) { 65 error = EEXIST; 66 goto bad; 67 } 68 fmode &= ~FCREAT; 69 } 70 } else { 71 ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF; 72 if (error = namei(ndp)) 73 return (error); 74 vp = ndp->ni_vp; 75 } 76 if (vp->v_type == VSOCK) { 77 error = EOPNOTSUPP; 78 goto bad; 79 } 80 if ((fmode & FCREAT) == 0) { 81 if (fmode & FREAD) { 82 if (error = VOP_ACCESS(vp, VREAD, ndp->ni_cred)) 83 goto bad; 84 } 85 if (fmode & (FWRITE|FTRUNC)) { 86 if (vp->v_type == VDIR) { 87 error = EISDIR; 88 goto bad; 89 } 90 if ((error = vn_writechk(vp)) || 91 (error = VOP_ACCESS(vp, VWRITE, ndp->ni_cred))) 92 goto bad; 93 } 94 } 95 if (fmode & FTRUNC) { 96 VATTR_NULL(vap); 97 vap->va_size = 0; 98 if (error = VOP_SETATTR(vp, vap, ndp->ni_cred)) 99 goto bad; 100 } 101 VOP_UNLOCK(vp); 102 error = VOP_OPEN(vp, fmode, ndp->ni_cred); 103 if (error) 104 vrele(vp); 105 return (error); 106 107 bad: 108 vput(vp); 109 return (error); 110 } 111 112 /* 113 * Check for write permissions on the specified vnode. 114 * The read-only status of the file system is checked. 115 * Also, prototype text segments cannot be written. 116 */ 117 vn_writechk(vp) 118 register struct vnode *vp; 119 { 120 121 /* 122 * Disallow write attempts on read-only file systems; 123 * unless the file is a socket or a block or character 124 * device resident on the file system. 125 */ 126 if (vp->v_mount->mnt_flag & MNT_RDONLY) { 127 switch (vp->v_type) { 128 case VREG: case VDIR: case VLNK: 129 return (EROFS); 130 } 131 } 132 /* 133 * If there's shared text associated with 134 * the vnode, try to free it up once. If 135 * we fail, we can't allow writing. 136 */ 137 if (vp->v_flag & VTEXT) 138 xrele(vp); 139 if (vp->v_flag & VTEXT) 140 return (ETXTBSY); 141 return (0); 142 } 143 144 /* 145 * Vnode version of rdwri() for calls on file systems. 146 */ 147 vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid) 148 enum uio_rw rw; 149 struct vnode *vp; 150 caddr_t base; 151 int len; 152 off_t offset; 153 enum uio_seg segflg; 154 int ioflg; 155 struct ucred *cred; 156 int *aresid; 157 { 158 struct uio auio; 159 struct iovec aiov; 160 int error; 161 162 if ((ioflg & IO_NODELOCKED) == 0) 163 VOP_LOCK(vp); 164 auio.uio_iov = &aiov; 165 auio.uio_iovcnt = 1; 166 aiov.iov_base = base; 167 aiov.iov_len = len; 168 auio.uio_resid = len; 169 auio.uio_offset = offset; 170 auio.uio_segflg = segflg; 171 auio.uio_rw = rw; 172 if (rw == UIO_READ) 173 error = VOP_READ(vp, &auio, ioflg, cred); 174 else 175 error = VOP_WRITE(vp, &auio, ioflg, cred); 176 if (aresid) 177 *aresid = auio.uio_resid; 178 else 179 if (auio.uio_resid && error == 0) 180 error = EIO; 181 if ((ioflg & IO_NODELOCKED) == 0) 182 VOP_UNLOCK(vp); 183 return (error); 184 } 185 186 vn_read(fp, uio, cred) 187 struct file *fp; 188 struct uio *uio; 189 struct ucred *cred; 190 { 191 register struct vnode *vp = (struct vnode *)fp->f_data; 192 int count, error; 193 194 VOP_LOCK(vp); 195 uio->uio_offset = fp->f_offset; 196 count = uio->uio_resid; 197 error = VOP_READ(vp, uio, (fp->f_flag & FNDELAY) ? IO_NDELAY : 0, cred); 198 fp->f_offset += count - uio->uio_resid; 199 VOP_UNLOCK(vp); 200 return (error); 201 } 202 203 vn_write(fp, uio, cred) 204 struct file *fp; 205 struct uio *uio; 206 struct ucred *cred; 207 { 208 register struct vnode *vp = (struct vnode *)fp->f_data; 209 int count, error, ioflag = 0; 210 211 if (vp->v_type == VREG && (fp->f_flag & FAPPEND)) 212 ioflag |= IO_APPEND; 213 if (fp->f_flag & FNDELAY) 214 ioflag |= IO_NDELAY; 215 VOP_LOCK(vp); 216 uio->uio_offset = fp->f_offset; 217 count = uio->uio_resid; 218 error = VOP_WRITE(vp, uio, ioflag, cred); 219 if (ioflag & IO_APPEND) 220 fp->f_offset = uio->uio_offset; 221 else 222 fp->f_offset += count - uio->uio_resid; 223 VOP_UNLOCK(vp); 224 return (error); 225 } 226 227 /* 228 * Get stat info for a vnode. 229 */ 230 vn_stat(vp, sb) 231 struct vnode *vp; 232 register struct stat *sb; 233 { 234 struct vattr vattr; 235 register struct vattr *vap; 236 int error; 237 u_short mode; 238 239 vap = &vattr; 240 error = VOP_GETATTR(vp, vap, u.u_cred); 241 if (error) 242 return (error); 243 /* 244 * Copy from vattr table 245 */ 246 sb->st_dev = vap->va_fsid; 247 sb->st_ino = vap->va_fileid; 248 mode = vap->va_mode; 249 switch (vp->v_type) { 250 case VREG: 251 mode |= S_IFREG; 252 break; 253 case VDIR: 254 mode |= S_IFDIR; 255 break; 256 case VBLK: 257 mode |= S_IFBLK; 258 break; 259 case VCHR: 260 mode |= S_IFCHR; 261 break; 262 case VLNK: 263 mode |= S_IFLNK; 264 break; 265 case VSOCK: 266 mode |= S_IFSOCK; 267 break; 268 case VFIFO: 269 mode |= S_IFIFO; 270 break; 271 default: 272 return (EBADF); 273 }; 274 sb->st_mode = mode; 275 sb->st_nlink = vap->va_nlink; 276 sb->st_uid = vap->va_uid; 277 sb->st_gid = vap->va_gid; 278 sb->st_rdev = vap->va_rdev; 279 sb->st_size = vap->va_size; 280 sb->st_atime = vap->va_atime.tv_sec; 281 sb->st_spare1 = 0; 282 sb->st_mtime = vap->va_mtime.tv_sec; 283 sb->st_spare2 = 0; 284 sb->st_ctime = vap->va_ctime.tv_sec; 285 sb->st_spare3 = 0; 286 sb->st_blksize = vap->va_blocksize; 287 sb->st_flags = vap->va_flags; 288 sb->st_gen = vap->va_gen; 289 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 290 return (0); 291 } 292 293 /* 294 * Vnode ioctl call 295 */ 296 vn_ioctl(fp, com, data) 297 struct file *fp; 298 int com; 299 caddr_t data; 300 { 301 register struct vnode *vp = ((struct vnode *)fp->f_data); 302 struct vattr vattr; 303 int error; 304 305 switch (vp->v_type) { 306 307 case VREG: 308 case VDIR: 309 if (com == FIONREAD) { 310 if (error = VOP_GETATTR(vp, &vattr, u.u_cred)) 311 return (error); 312 *(off_t *)data = vattr.va_size - fp->f_offset; 313 return (0); 314 } 315 if (com == FIONBIO || com == FIOASYNC) /* XXX */ 316 return (0); /* XXX */ 317 /* fall into ... */ 318 319 default: 320 return (ENOTTY); 321 322 case VFIFO: 323 case VCHR: 324 case VBLK: 325 error = VOP_IOCTL(vp, com, data, fp->f_flag, u.u_cred); 326 if (error == 0 && com == TIOCSCTTY) { 327 u.u_procp->p_session->s_ttyvp = vp; 328 VREF(vp); 329 } 330 return (error); 331 } 332 } 333 334 /* 335 * Vnode select call 336 */ 337 vn_select(fp, which) 338 struct file *fp; 339 int which; 340 { 341 return (VOP_SELECT(((struct vnode *)fp->f_data), which, fp->f_flag, 342 u.u_cred)); 343 } 344 345 /* 346 * Vnode close call 347 */ 348 vn_close(fp) 349 register struct file *fp; 350 { 351 struct vnode *vp = ((struct vnode *)fp->f_data); 352 int error; 353 354 if (fp->f_flag & (FSHLOCK|FEXLOCK)) 355 vn_unlock(fp, FSHLOCK|FEXLOCK); 356 /* 357 * Must delete vnode reference from this file entry 358 * before VOP_CLOSE, so that only other references 359 * will prevent close. 360 */ 361 fp->f_data = (caddr_t) 0; 362 error = VOP_CLOSE(vp, fp->f_flag, u.u_cred); 363 vrele(vp); 364 return (error); 365 } 366 367 /* 368 * Place an advisory lock on a vnode. 369 * !! THIS IMPLIES THAT ALL STATEFUL FILE SERVERS WILL USE file table entries 370 */ 371 vn_lock(fp, cmd) 372 register struct file *fp; 373 int cmd; 374 { 375 register int priority = PLOCK; 376 register struct vnode *vp = (struct vnode *)fp->f_data; 377 int error = 0; 378 static char lockstr[] = "flock"; 379 380 if ((cmd & LOCK_EX) == 0) 381 priority += 4; 382 priority |= PCATCH; 383 384 /* 385 * If there's a exclusive lock currently applied 386 * to the file, then we've gotta wait for the 387 * lock with everyone else. 388 */ 389 again: 390 while (vp->v_flag & VEXLOCK) { 391 /* 392 * If we're holding an exclusive 393 * lock, then release it. 394 */ 395 if (fp->f_flag & FEXLOCK) { 396 vn_unlock(fp, FEXLOCK); 397 continue; 398 } 399 if (cmd & LOCK_NB) 400 return (EWOULDBLOCK); 401 vp->v_flag |= VLWAIT; 402 if (error = tsleep((caddr_t)&vp->v_exlockc, priority, 403 lockstr, 0)) 404 return (error); 405 } 406 if (error == 0 && (cmd & LOCK_EX) && (vp->v_flag & VSHLOCK)) { 407 /* 408 * Must wait for any shared locks to finish 409 * before we try to apply a exclusive lock. 410 * 411 * If we're holding a shared 412 * lock, then release it. 413 */ 414 if (fp->f_flag & FSHLOCK) { 415 vn_unlock(fp, FSHLOCK); 416 goto again; 417 } 418 if (cmd & LOCK_NB) 419 return (EWOULDBLOCK); 420 vp->v_flag |= VLWAIT; 421 if (error = tsleep((caddr_t)&vp->v_shlockc, PLOCK | PCATCH, 422 lockstr, 0)) 423 return (error); 424 } 425 if (fp->f_flag & FEXLOCK) 426 panic("vn_lock"); 427 if (cmd & LOCK_EX) { 428 cmd &= ~LOCK_SH; 429 vp->v_exlockc++; 430 vp->v_flag |= VEXLOCK; 431 fp->f_flag |= FEXLOCK; 432 } 433 if ((cmd & LOCK_SH) && (fp->f_flag & FSHLOCK) == 0) { 434 vp->v_shlockc++; 435 vp->v_flag |= VSHLOCK; 436 fp->f_flag |= FSHLOCK; 437 } 438 return (0); 439 } 440 441 /* 442 * Unlock a file. 443 */ 444 vn_unlock(fp, kind) 445 register struct file *fp; 446 int kind; 447 { 448 register struct vnode *vp = (struct vnode *)fp->f_data; 449 int flags; 450 451 kind &= fp->f_flag; 452 if (vp == NULL || kind == 0) 453 return; 454 flags = vp->v_flag; 455 if (kind & FSHLOCK) { 456 if ((flags & VSHLOCK) == 0) 457 panic("vn_unlock: SHLOCK"); 458 if (--vp->v_shlockc == 0) { 459 vp->v_flag &= ~VSHLOCK; 460 if (flags & VLWAIT) 461 wakeup((caddr_t)&vp->v_shlockc); 462 } 463 fp->f_flag &= ~FSHLOCK; 464 } 465 if (kind & FEXLOCK) { 466 if ((flags & VEXLOCK) == 0) 467 panic("vn_unlock: EXLOCK"); 468 if (--vp->v_exlockc == 0) { 469 vp->v_flag &= ~(VEXLOCK|VLWAIT); 470 if (flags & VLWAIT) 471 wakeup((caddr_t)&vp->v_exlockc); 472 } 473 fp->f_flag &= ~FEXLOCK; 474 } 475 } 476 477 /* 478 * vn_fhtovp() - convert a fh to a vnode ptr (optionally locked) 479 * - look up fsid in mount list (if not found ret error) 480 * - get vp by calling VFS_FHTOVP() macro 481 * - if lockflag lock it with VOP_LOCK() 482 */ 483 vn_fhtovp(fhp, lockflag, vpp) 484 fhandle_t *fhp; 485 int lockflag; 486 struct vnode **vpp; 487 { 488 register struct mount *mp; 489 490 if ((mp = getvfs(&fhp->fh_fsid)) == NULL) 491 return (ESTALE); 492 if (VFS_FHTOVP(mp, &fhp->fh_fid, vpp)) 493 return (ESTALE); 494 if (!lockflag) 495 VOP_UNLOCK(*vpp); 496 return (0); 497 } 498 499 /* 500 * Noop 501 */ 502 vfs_noop() 503 { 504 505 return (ENXIO); 506 } 507 508 /* 509 * Null op 510 */ 511 vfs_nullop() 512 { 513 514 return (0); 515 } 516