1 /*- 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)fdesc_vnops.c 8.9 (Berkeley) 1/21/94 33 * 34 * $FreeBSD$ 35 */ 36 37 /* 38 * /dev/fd Filesystem 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/conf.h> 44 #include <sys/dirent.h> 45 #include <sys/filedesc.h> 46 #include <sys/kernel.h> /* boottime */ 47 #include <sys/lock.h> 48 #include <sys/mutex.h> 49 #include <sys/malloc.h> 50 #include <sys/file.h> /* Must come after sys/malloc.h */ 51 #include <sys/mount.h> 52 #include <sys/namei.h> 53 #include <sys/proc.h> 54 #include <sys/stat.h> 55 #include <sys/vnode.h> 56 57 #include <fs/fdescfs/fdesc.h> 58 59 #define NFDCACHE 4 60 #define FD_NHASH(ix) \ 61 (&fdhashtbl[(ix) & fdhash]) 62 static LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl; 63 static u_long fdhash; 64 65 struct mtx fdesc_hashmtx; 66 67 static vop_getattr_t fdesc_getattr; 68 static vop_lookup_t fdesc_lookup; 69 static vop_open_t fdesc_open; 70 static vop_readdir_t fdesc_readdir; 71 static vop_reclaim_t fdesc_reclaim; 72 static vop_setattr_t fdesc_setattr; 73 74 static struct vop_vector fdesc_vnodeops = { 75 .vop_default = &default_vnodeops, 76 77 .vop_access = VOP_NULL, 78 .vop_getattr = fdesc_getattr, 79 .vop_lookup = fdesc_lookup, 80 .vop_open = fdesc_open, 81 .vop_pathconf = vop_stdpathconf, 82 .vop_readdir = fdesc_readdir, 83 .vop_reclaim = fdesc_reclaim, 84 .vop_setattr = fdesc_setattr, 85 }; 86 87 static void fdesc_insmntque_dtr(struct vnode *, void *); 88 static void fdesc_remove_entry(struct fdescnode *); 89 90 /* 91 * Initialise cache headers 92 */ 93 int 94 fdesc_init(vfsp) 95 struct vfsconf *vfsp; 96 { 97 98 mtx_init(&fdesc_hashmtx, "fdescfs_hash", NULL, MTX_DEF); 99 fdhashtbl = hashinit(NFDCACHE, M_CACHE, &fdhash); 100 return (0); 101 } 102 103 /* 104 * Uninit ready for unload. 105 */ 106 int 107 fdesc_uninit(vfsp) 108 struct vfsconf *vfsp; 109 { 110 111 hashdestroy(fdhashtbl, M_CACHE, fdhash); 112 mtx_destroy(&fdesc_hashmtx); 113 return (0); 114 } 115 116 /* 117 * If allocating vnode fails, call this. 118 */ 119 static void 120 fdesc_insmntque_dtr(struct vnode *vp, void *arg) 121 { 122 123 vgone(vp); 124 vput(vp); 125 } 126 127 /* 128 * Remove an entry from the hash if it exists. 129 */ 130 static void 131 fdesc_remove_entry(struct fdescnode *fd) 132 { 133 struct fdhashhead *fc; 134 struct fdescnode *fd2; 135 136 fc = FD_NHASH(fd->fd_ix); 137 mtx_lock(&fdesc_hashmtx); 138 LIST_FOREACH(fd2, fc, fd_hash) { 139 if (fd == fd2) { 140 LIST_REMOVE(fd, fd_hash); 141 break; 142 } 143 } 144 mtx_unlock(&fdesc_hashmtx); 145 } 146 147 int 148 fdesc_allocvp(ftype, fd_fd, ix, mp, vpp, td) 149 fdntype ftype; 150 unsigned fd_fd; 151 int ix; 152 struct mount *mp; 153 struct vnode **vpp; 154 struct thread *td; 155 { 156 struct fdescmount *fmp; 157 struct fdhashhead *fc; 158 struct fdescnode *fd, *fd2; 159 struct vnode *vp, *vp2; 160 int error = 0; 161 162 fc = FD_NHASH(ix); 163 loop: 164 mtx_lock(&fdesc_hashmtx); 165 /* 166 * If a forced unmount is progressing, we need to drop it. The flags are 167 * protected by the hashmtx. 168 */ 169 fmp = (struct fdescmount *)mp->mnt_data; 170 if (fmp == NULL || fmp->flags & FMNT_UNMOUNTF) { 171 mtx_unlock(&fdesc_hashmtx); 172 return (-1); 173 } 174 175 LIST_FOREACH(fd, fc, fd_hash) { 176 if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) { 177 /* Get reference to vnode in case it's being free'd */ 178 vp = fd->fd_vnode; 179 VI_LOCK(vp); 180 mtx_unlock(&fdesc_hashmtx); 181 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, td)) 182 goto loop; 183 *vpp = vp; 184 return (0); 185 } 186 } 187 mtx_unlock(&fdesc_hashmtx); 188 189 fd = malloc(sizeof(struct fdescnode), M_TEMP, M_WAITOK); 190 191 error = getnewvnode("fdescfs", mp, &fdesc_vnodeops, &vp); 192 if (error) { 193 free(fd, M_TEMP); 194 return (error); 195 } 196 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 197 vp->v_data = fd; 198 fd->fd_vnode = vp; 199 fd->fd_type = ftype; 200 fd->fd_fd = fd_fd; 201 fd->fd_ix = ix; 202 error = insmntque1(vp, mp, fdesc_insmntque_dtr, NULL); 203 if (error != 0) { 204 *vpp = NULLVP; 205 return (error); 206 } 207 208 /* Make sure that someone didn't beat us when inserting the vnode. */ 209 mtx_lock(&fdesc_hashmtx); 210 /* 211 * If a forced unmount is progressing, we need to drop it. The flags are 212 * protected by the hashmtx. 213 */ 214 fmp = (struct fdescmount *)mp->mnt_data; 215 if (fmp == NULL || fmp->flags & FMNT_UNMOUNTF) { 216 mtx_unlock(&fdesc_hashmtx); 217 vgone(vp); 218 vput(vp); 219 *vpp = NULLVP; 220 return (-1); 221 } 222 223 LIST_FOREACH(fd2, fc, fd_hash) { 224 if (fd2->fd_ix == ix && fd2->fd_vnode->v_mount == mp) { 225 /* Get reference to vnode in case it's being free'd */ 226 vp2 = fd2->fd_vnode; 227 VI_LOCK(vp2); 228 mtx_unlock(&fdesc_hashmtx); 229 error = vget(vp2, LK_EXCLUSIVE | LK_INTERLOCK, td); 230 /* Someone beat us, dec use count and wait for reclaim */ 231 vgone(vp); 232 vput(vp); 233 /* If we didn't get it, return no vnode. */ 234 if (error) 235 vp2 = NULLVP; 236 *vpp = vp2; 237 return (error); 238 } 239 } 240 241 /* If we came here, we can insert it safely. */ 242 LIST_INSERT_HEAD(fc, fd, fd_hash); 243 mtx_unlock(&fdesc_hashmtx); 244 *vpp = vp; 245 return (0); 246 } 247 248 /* 249 * vp is the current namei directory 250 * ndp is the name to locate in that directory... 251 */ 252 static int 253 fdesc_lookup(ap) 254 struct vop_lookup_args /* { 255 struct vnode * a_dvp; 256 struct vnode ** a_vpp; 257 struct componentname * a_cnp; 258 } */ *ap; 259 { 260 struct vnode **vpp = ap->a_vpp; 261 struct vnode *dvp = ap->a_dvp; 262 struct componentname *cnp = ap->a_cnp; 263 char *pname = cnp->cn_nameptr; 264 struct thread *td = cnp->cn_thread; 265 struct file *fp; 266 int nlen = cnp->cn_namelen; 267 u_int fd; 268 int error; 269 struct vnode *fvp; 270 271 if ((cnp->cn_flags & ISLASTCN) && 272 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 273 error = EROFS; 274 goto bad; 275 } 276 277 if (cnp->cn_namelen == 1 && *pname == '.') { 278 *vpp = dvp; 279 VREF(dvp); 280 return (0); 281 } 282 283 if (VTOFDESC(dvp)->fd_type != Froot) { 284 error = ENOTDIR; 285 goto bad; 286 } 287 288 fd = 0; 289 /* the only time a leading 0 is acceptable is if it's "0" */ 290 if (*pname == '0' && nlen != 1) { 291 error = ENOENT; 292 goto bad; 293 } 294 while (nlen--) { 295 if (*pname < '0' || *pname > '9') { 296 error = ENOENT; 297 goto bad; 298 } 299 fd = 10 * fd + *pname++ - '0'; 300 } 301 302 if ((error = fget(td, fd, &fp)) != 0) 303 goto bad; 304 305 /* Check if we're looking up ourselves. */ 306 if (VTOFDESC(dvp)->fd_ix == FD_DESC + fd) { 307 /* 308 * In case we're holding the last reference to the file, the dvp 309 * will be re-acquired. 310 */ 311 vhold(dvp); 312 VOP_UNLOCK(dvp, 0); 313 fdrop(fp, td); 314 315 /* Re-aquire the lock afterwards. */ 316 vn_lock(dvp, LK_RETRY | LK_EXCLUSIVE); 317 vdrop(dvp); 318 fvp = dvp; 319 } else { 320 /* 321 * Unlock our root node (dvp) when doing this, since we might 322 * deadlock since the vnode might be locked by another thread 323 * and the root vnode lock will be obtained afterwards (in case 324 * we're looking up the fd of the root vnode), which will be the 325 * opposite lock order. Vhold the root vnode first so we don't 326 * loose it. 327 */ 328 vhold(dvp); 329 VOP_UNLOCK(dvp, 0); 330 error = fdesc_allocvp(Fdesc, fd, FD_DESC + fd, dvp->v_mount, 331 &fvp, td); 332 fdrop(fp, td); 333 /* 334 * The root vnode must be locked last to prevent deadlock condition. 335 */ 336 vn_lock(dvp, LK_RETRY | LK_EXCLUSIVE); 337 vdrop(dvp); 338 } 339 340 if (error) 341 goto bad; 342 *vpp = fvp; 343 return (0); 344 345 bad: 346 *vpp = NULL; 347 return (error); 348 } 349 350 static int 351 fdesc_open(ap) 352 struct vop_open_args /* { 353 struct vnode *a_vp; 354 int a_mode; 355 struct ucred *a_cred; 356 struct thread *a_td; 357 } */ *ap; 358 { 359 struct vnode *vp = ap->a_vp; 360 361 if (VTOFDESC(vp)->fd_type == Froot) 362 return (0); 363 364 /* 365 * XXX Kludge: set td->td_proc->p_dupfd to contain the value of the the file 366 * descriptor being sought for duplication. The error return ensures 367 * that the vnode for this device will be released by vn_open. Open 368 * will detect this special error and take the actions in dupfdopen. 369 * Other callers of vn_open or VOP_OPEN will simply report the 370 * error. 371 */ 372 ap->a_td->td_dupfd = VTOFDESC(vp)->fd_fd; /* XXX */ 373 return (ENODEV); 374 } 375 376 static int 377 fdesc_getattr(ap) 378 struct vop_getattr_args /* { 379 struct vnode *a_vp; 380 struct vattr *a_vap; 381 struct ucred *a_cred; 382 } */ *ap; 383 { 384 struct vnode *vp = ap->a_vp; 385 struct vattr *vap = ap->a_vap; 386 struct thread *td = curthread; 387 struct file *fp; 388 struct stat stb; 389 u_int fd; 390 int error = 0; 391 392 switch (VTOFDESC(vp)->fd_type) { 393 case Froot: 394 vap->va_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH; 395 vap->va_type = VDIR; 396 vap->va_nlink = 2; 397 vap->va_size = DEV_BSIZE; 398 vap->va_fileid = VTOFDESC(vp)->fd_ix; 399 vap->va_uid = 0; 400 vap->va_gid = 0; 401 vap->va_blocksize = DEV_BSIZE; 402 vap->va_atime.tv_sec = boottime.tv_sec; 403 vap->va_atime.tv_nsec = 0; 404 vap->va_mtime = vap->va_atime; 405 vap->va_ctime = vap->va_mtime; 406 vap->va_gen = 0; 407 vap->va_flags = 0; 408 vap->va_rdev = NODEV; 409 vap->va_bytes = 0; 410 vap->va_filerev = 0; 411 break; 412 413 case Fdesc: 414 fd = VTOFDESC(vp)->fd_fd; 415 416 if ((error = fget(td, fd, &fp)) != 0) 417 return (error); 418 419 bzero(&stb, sizeof(stb)); 420 error = fo_stat(fp, &stb, td->td_ucred, td); 421 fdrop(fp, td); 422 if (error == 0) { 423 vap->va_type = IFTOVT(stb.st_mode); 424 vap->va_mode = stb.st_mode; 425 if (vap->va_type == VDIR) 426 vap->va_mode &= ~(S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH); 427 vap->va_nlink = 1; 428 vap->va_flags = 0; 429 vap->va_bytes = stb.st_blocks * stb.st_blksize; 430 vap->va_fileid = VTOFDESC(vp)->fd_ix; 431 vap->va_size = stb.st_size; 432 vap->va_blocksize = stb.st_blksize; 433 vap->va_rdev = stb.st_rdev; 434 435 /* 436 * If no time data is provided, use the current time. 437 */ 438 if (stb.st_atimespec.tv_sec == 0 && 439 stb.st_atimespec.tv_nsec == 0) 440 nanotime(&stb.st_atimespec); 441 442 if (stb.st_ctimespec.tv_sec == 0 && 443 stb.st_ctimespec.tv_nsec == 0) 444 nanotime(&stb.st_ctimespec); 445 446 if (stb.st_mtimespec.tv_sec == 0 && 447 stb.st_mtimespec.tv_nsec == 0) 448 nanotime(&stb.st_mtimespec); 449 450 vap->va_atime = stb.st_atimespec; 451 vap->va_mtime = stb.st_mtimespec; 452 vap->va_ctime = stb.st_ctimespec; 453 vap->va_uid = stb.st_uid; 454 vap->va_gid = stb.st_gid; 455 vap->va_gen = 0; 456 vap->va_filerev = 0; 457 } 458 break; 459 460 default: 461 panic("fdesc_getattr"); 462 break; 463 } 464 465 if (error == 0) 466 vp->v_type = vap->va_type; 467 return (error); 468 } 469 470 static int 471 fdesc_setattr(ap) 472 struct vop_setattr_args /* { 473 struct vnode *a_vp; 474 struct vattr *a_vap; 475 struct ucred *a_cred; 476 } */ *ap; 477 { 478 struct vattr *vap = ap->a_vap; 479 struct vnode *vp; 480 struct mount *mp; 481 struct file *fp; 482 struct thread *td = curthread; 483 unsigned fd; 484 int error; 485 486 /* 487 * Can't mess with the root vnode 488 */ 489 if (VTOFDESC(ap->a_vp)->fd_type == Froot) 490 return (EACCES); 491 492 fd = VTOFDESC(ap->a_vp)->fd_fd; 493 494 /* 495 * Allow setattr where there is an underlying vnode. 496 */ 497 error = getvnode(td->td_proc->p_fd, fd, &fp); 498 if (error) { 499 /* 500 * getvnode() returns EINVAL if the file descriptor is not 501 * backed by a vnode. Silently drop all changes except 502 * chflags(2) in this case. 503 */ 504 if (error == EINVAL) { 505 if (vap->va_flags != VNOVAL) 506 error = EOPNOTSUPP; 507 else 508 error = 0; 509 } 510 return (error); 511 } 512 vp = fp->f_vnode; 513 if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) == 0) { 514 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 515 error = VOP_SETATTR(vp, ap->a_vap, ap->a_cred); 516 VOP_UNLOCK(vp, 0); 517 vn_finished_write(mp); 518 } 519 fdrop(fp, td); 520 return (error); 521 } 522 523 #define UIO_MX 16 524 525 static int 526 fdesc_readdir(ap) 527 struct vop_readdir_args /* { 528 struct vnode *a_vp; 529 struct uio *a_uio; 530 struct ucred *a_cred; 531 int *a_eofflag; 532 u_long *a_cookies; 533 int a_ncookies; 534 } */ *ap; 535 { 536 struct uio *uio = ap->a_uio; 537 struct filedesc *fdp; 538 struct dirent d; 539 struct dirent *dp = &d; 540 int error, i, off, fcnt; 541 542 /* 543 * We don't allow exporting fdesc mounts, and currently local 544 * requests do not need cookies. 545 */ 546 if (ap->a_ncookies) 547 panic("fdesc_readdir: not hungry"); 548 549 if (VTOFDESC(ap->a_vp)->fd_type != Froot) 550 panic("fdesc_readdir: not dir"); 551 552 off = (int)uio->uio_offset; 553 if (off != uio->uio_offset || off < 0 || (u_int)off % UIO_MX != 0 || 554 uio->uio_resid < UIO_MX) 555 return (EINVAL); 556 i = (u_int)off / UIO_MX; 557 fdp = uio->uio_td->td_proc->p_fd; 558 error = 0; 559 560 fcnt = i - 2; /* The first two nodes are `.' and `..' */ 561 562 FILEDESC_SLOCK(fdp); 563 while (i < fdp->fd_nfiles + 2 && uio->uio_resid >= UIO_MX) { 564 switch (i) { 565 case 0: /* `.' */ 566 case 1: /* `..' */ 567 bzero((caddr_t)dp, UIO_MX); 568 569 dp->d_fileno = i + FD_ROOT; 570 dp->d_namlen = i + 1; 571 dp->d_reclen = UIO_MX; 572 bcopy("..", dp->d_name, dp->d_namlen); 573 dp->d_name[i + 1] = '\0'; 574 dp->d_type = DT_DIR; 575 break; 576 default: 577 if (fdp->fd_ofiles[fcnt] == NULL) { 578 FILEDESC_SUNLOCK(fdp); 579 goto done; 580 } 581 582 bzero((caddr_t) dp, UIO_MX); 583 dp->d_namlen = sprintf(dp->d_name, "%d", fcnt); 584 dp->d_reclen = UIO_MX; 585 dp->d_type = DT_UNKNOWN; 586 dp->d_fileno = i + FD_DESC; 587 break; 588 } 589 /* 590 * And ship to userland 591 */ 592 FILEDESC_SUNLOCK(fdp); 593 error = uiomove(dp, UIO_MX, uio); 594 if (error) 595 goto done; 596 FILEDESC_SLOCK(fdp); 597 i++; 598 fcnt++; 599 } 600 FILEDESC_SUNLOCK(fdp); 601 602 done: 603 uio->uio_offset = i * UIO_MX; 604 return (error); 605 } 606 607 static int 608 fdesc_reclaim(ap) 609 struct vop_reclaim_args /* { 610 struct vnode *a_vp; 611 } */ *ap; 612 { 613 struct vnode *vp; 614 struct fdescnode *fd; 615 616 vp = ap->a_vp; 617 fd = VTOFDESC(vp); 618 fdesc_remove_entry(fd); 619 free(vp->v_data, M_TEMP); 620 vp->v_data = NULL; 621 return (0); 622 } 623