1 /* 2 * Copyright (c) 2005 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Jeffrey Hsu. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * 35 * Copyright (c) 1982, 1986, 1989, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by the University of 54 * California, Berkeley and its contributors. 55 * 4. Neither the name of the University nor the names of its contributors 56 * may be used to endorse or promote products derived from this software 57 * without specific prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 62 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 69 * SUCH DAMAGE. 70 * 71 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 72 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $ 73 */ 74 75 #include "opt_compat.h" 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/malloc.h> 79 #include <sys/sysproto.h> 80 #include <sys/conf.h> 81 #include <sys/device.h> 82 #include <sys/file.h> 83 #include <sys/filedesc.h> 84 #include <sys/kernel.h> 85 #include <sys/sysctl.h> 86 #include <sys/vnode.h> 87 #include <sys/proc.h> 88 #include <sys/nlookup.h> 89 #include <sys/file.h> 90 #include <sys/stat.h> 91 #include <sys/filio.h> 92 #include <sys/fcntl.h> 93 #include <sys/unistd.h> 94 #include <sys/resourcevar.h> 95 #include <sys/event.h> 96 #include <sys/kern_syscall.h> 97 #include <sys/kcore.h> 98 #include <sys/kinfo.h> 99 #include <sys/un.h> 100 101 #include <vm/vm.h> 102 #include <vm/vm_extern.h> 103 104 #include <sys/thread2.h> 105 #include <sys/file2.h> 106 #include <sys/spinlock2.h> 107 #include <sys/mplock2.h> 108 109 static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd); 110 static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr); 111 static struct file *funsetfd_locked (struct filedesc *fdp, int fd); 112 static void ffree(struct file *fp); 113 114 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 115 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 116 "file desc to leader structures"); 117 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 118 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 119 120 static struct krate krate_uidinfo = { .freq = 1 }; 121 122 static d_open_t fdopen; 123 #define NUMFDESC 64 124 125 #define CDEV_MAJOR 22 126 static struct dev_ops fildesc_ops = { 127 { "FD", 0, 0 }, 128 .d_open = fdopen, 129 }; 130 131 /* 132 * Descriptor management. 133 */ 134 static struct filelist filehead = LIST_HEAD_INITIALIZER(&filehead); 135 static struct spinlock filehead_spin = SPINLOCK_INITIALIZER(&filehead_spin); 136 static int nfiles; /* actual number of open files */ 137 extern int cmask; 138 139 /* 140 * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared. 141 * 142 * MPSAFE - must be called with fdp->fd_spin exclusively held 143 */ 144 static __inline 145 void 146 fdfixup_locked(struct filedesc *fdp, int fd) 147 { 148 if (fd < fdp->fd_freefile) { 149 fdp->fd_freefile = fd; 150 } 151 while (fdp->fd_lastfile >= 0 && 152 fdp->fd_files[fdp->fd_lastfile].fp == NULL && 153 fdp->fd_files[fdp->fd_lastfile].reserved == 0 154 ) { 155 --fdp->fd_lastfile; 156 } 157 } 158 159 /* 160 * System calls on descriptors. 161 * 162 * MPSAFE 163 */ 164 int 165 sys_getdtablesize(struct getdtablesize_args *uap) 166 { 167 struct proc *p = curproc; 168 struct plimit *limit = p->p_limit; 169 int dtsize; 170 171 spin_lock(&limit->p_spin); 172 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 173 dtsize = INT_MAX; 174 else 175 dtsize = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 176 spin_unlock(&limit->p_spin); 177 178 if (dtsize > maxfilesperproc) 179 dtsize = maxfilesperproc; 180 if (dtsize < minfilesperproc) 181 dtsize = minfilesperproc; 182 if (p->p_ucred->cr_uid && dtsize > maxfilesperuser) 183 dtsize = maxfilesperuser; 184 uap->sysmsg_result = dtsize; 185 return (0); 186 } 187 188 /* 189 * Duplicate a file descriptor to a particular value. 190 * 191 * note: keep in mind that a potential race condition exists when closing 192 * descriptors from a shared descriptor table (via rfork). 193 * 194 * MPSAFE 195 */ 196 int 197 sys_dup2(struct dup2_args *uap) 198 { 199 int error; 200 int fd = 0; 201 202 error = kern_dup(DUP_FIXED, uap->from, uap->to, &fd); 203 uap->sysmsg_fds[0] = fd; 204 205 return (error); 206 } 207 208 /* 209 * Duplicate a file descriptor. 210 * 211 * MPSAFE 212 */ 213 int 214 sys_dup(struct dup_args *uap) 215 { 216 int error; 217 int fd = 0; 218 219 error = kern_dup(DUP_VARIABLE, uap->fd, 0, &fd); 220 uap->sysmsg_fds[0] = fd; 221 222 return (error); 223 } 224 225 /* 226 * MPALMOSTSAFE - acquires mplock for fp operations 227 */ 228 int 229 kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred) 230 { 231 struct thread *td = curthread; 232 struct proc *p = td->td_proc; 233 struct file *fp; 234 struct vnode *vp; 235 u_int newmin; 236 u_int oflags; 237 u_int nflags; 238 int tmp, error, flg = F_POSIX; 239 240 KKASSERT(p); 241 242 /* 243 * Operations on file descriptors that do not require a file pointer. 244 */ 245 switch (cmd) { 246 case F_GETFD: 247 error = fgetfdflags(p->p_fd, fd, &tmp); 248 if (error == 0) 249 dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0; 250 return (error); 251 252 case F_SETFD: 253 if (dat->fc_cloexec & FD_CLOEXEC) 254 error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE); 255 else 256 error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE); 257 return (error); 258 case F_DUPFD: 259 newmin = dat->fc_fd; 260 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); 261 return (error); 262 default: 263 break; 264 } 265 266 /* 267 * Operations on file pointers 268 */ 269 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 270 return (EBADF); 271 272 get_mplock(); 273 switch (cmd) { 274 case F_GETFL: 275 dat->fc_flags = OFLAGS(fp->f_flag); 276 error = 0; 277 break; 278 279 case F_SETFL: 280 oflags = fp->f_flag; 281 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 282 nflags |= oflags & ~FCNTLFLAGS; 283 284 error = 0; 285 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) 286 error = EINVAL; 287 if (error == 0 && ((nflags ^ oflags) & FASYNC)) { 288 tmp = nflags & FASYNC; 289 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, 290 cred, NULL); 291 } 292 if (error == 0) 293 fp->f_flag = nflags; 294 break; 295 296 case F_GETOWN: 297 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, 298 cred, NULL); 299 break; 300 301 case F_SETOWN: 302 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, 303 cred, NULL); 304 break; 305 306 case F_SETLKW: 307 flg |= F_WAIT; 308 /* Fall into F_SETLK */ 309 310 case F_SETLK: 311 if (fp->f_type != DTYPE_VNODE) { 312 error = EBADF; 313 break; 314 } 315 vp = (struct vnode *)fp->f_data; 316 317 /* 318 * copyin/lockop may block 319 */ 320 if (dat->fc_flock.l_whence == SEEK_CUR) 321 dat->fc_flock.l_start += fp->f_offset; 322 323 switch (dat->fc_flock.l_type) { 324 case F_RDLCK: 325 if ((fp->f_flag & FREAD) == 0) { 326 error = EBADF; 327 break; 328 } 329 p->p_leader->p_flag |= P_ADVLOCK; 330 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 331 &dat->fc_flock, flg); 332 break; 333 case F_WRLCK: 334 if ((fp->f_flag & FWRITE) == 0) { 335 error = EBADF; 336 break; 337 } 338 p->p_leader->p_flag |= P_ADVLOCK; 339 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 340 &dat->fc_flock, flg); 341 break; 342 case F_UNLCK: 343 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 344 &dat->fc_flock, F_POSIX); 345 break; 346 default: 347 error = EINVAL; 348 break; 349 } 350 351 /* 352 * It is possible to race a close() on the descriptor while 353 * we were blocked getting the lock. If this occurs the 354 * close might not have caught the lock. 355 */ 356 if (checkfdclosed(p->p_fd, fd, fp)) { 357 dat->fc_flock.l_whence = SEEK_SET; 358 dat->fc_flock.l_start = 0; 359 dat->fc_flock.l_len = 0; 360 dat->fc_flock.l_type = F_UNLCK; 361 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 362 F_UNLCK, &dat->fc_flock, F_POSIX); 363 } 364 break; 365 366 case F_GETLK: 367 if (fp->f_type != DTYPE_VNODE) { 368 error = EBADF; 369 break; 370 } 371 vp = (struct vnode *)fp->f_data; 372 /* 373 * copyin/lockop may block 374 */ 375 if (dat->fc_flock.l_type != F_RDLCK && 376 dat->fc_flock.l_type != F_WRLCK && 377 dat->fc_flock.l_type != F_UNLCK) { 378 error = EINVAL; 379 break; 380 } 381 if (dat->fc_flock.l_whence == SEEK_CUR) 382 dat->fc_flock.l_start += fp->f_offset; 383 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 384 &dat->fc_flock, F_POSIX); 385 break; 386 default: 387 error = EINVAL; 388 break; 389 } 390 rel_mplock(); 391 392 fdrop(fp); 393 return (error); 394 } 395 396 /* 397 * The file control system call. 398 * 399 * MPSAFE 400 */ 401 int 402 sys_fcntl(struct fcntl_args *uap) 403 { 404 union fcntl_dat dat; 405 int error; 406 407 switch (uap->cmd) { 408 case F_DUPFD: 409 dat.fc_fd = uap->arg; 410 break; 411 case F_SETFD: 412 dat.fc_cloexec = uap->arg; 413 break; 414 case F_SETFL: 415 dat.fc_flags = uap->arg; 416 break; 417 case F_SETOWN: 418 dat.fc_owner = uap->arg; 419 break; 420 case F_SETLKW: 421 case F_SETLK: 422 case F_GETLK: 423 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 424 sizeof(struct flock)); 425 if (error) 426 return (error); 427 break; 428 } 429 430 error = kern_fcntl(uap->fd, uap->cmd, &dat, curthread->td_ucred); 431 432 if (error == 0) { 433 switch (uap->cmd) { 434 case F_DUPFD: 435 uap->sysmsg_result = dat.fc_fd; 436 break; 437 case F_GETFD: 438 uap->sysmsg_result = dat.fc_cloexec; 439 break; 440 case F_GETFL: 441 uap->sysmsg_result = dat.fc_flags; 442 break; 443 case F_GETOWN: 444 uap->sysmsg_result = dat.fc_owner; 445 case F_GETLK: 446 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 447 sizeof(struct flock)); 448 break; 449 } 450 } 451 452 return (error); 453 } 454 455 /* 456 * Common code for dup, dup2, and fcntl(F_DUPFD). 457 * 458 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells 459 * kern_dup() to destructively dup over an existing file descriptor if new 460 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest 461 * unused file descriptor that is greater than or equal to new. 462 * 463 * MPSAFE 464 */ 465 int 466 kern_dup(enum dup_type type, int old, int new, int *res) 467 { 468 struct thread *td = curthread; 469 struct proc *p = td->td_proc; 470 struct filedesc *fdp = p->p_fd; 471 struct file *fp; 472 struct file *delfp; 473 int oldflags; 474 int holdleaders; 475 int dtsize; 476 int error, newfd; 477 478 /* 479 * Verify that we have a valid descriptor to dup from and 480 * possibly to dup to. 481 * 482 * NOTE: maxfilesperuser is not applicable to dup() 483 */ 484 retry: 485 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 486 dtsize = INT_MAX; 487 else 488 dtsize = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 489 if (dtsize > maxfilesperproc) 490 dtsize = maxfilesperproc; 491 if (dtsize < minfilesperproc) 492 dtsize = minfilesperproc; 493 494 if (new < 0 || new > dtsize) 495 return (EINVAL); 496 497 spin_lock(&fdp->fd_spin); 498 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { 499 spin_unlock(&fdp->fd_spin); 500 return (EBADF); 501 } 502 if (type == DUP_FIXED && old == new) { 503 *res = new; 504 spin_unlock(&fdp->fd_spin); 505 return (0); 506 } 507 fp = fdp->fd_files[old].fp; 508 oldflags = fdp->fd_files[old].fileflags; 509 fhold(fp); /* MPSAFE - can be called with a spinlock held */ 510 511 /* 512 * Allocate a new descriptor if DUP_VARIABLE, or expand the table 513 * if the requested descriptor is beyond the current table size. 514 * 515 * This can block. Retry if the source descriptor no longer matches 516 * or if our expectation in the expansion case races. 517 * 518 * If we are not expanding or allocating a new decriptor, then reset 519 * the target descriptor to a reserved state so we have a uniform 520 * setup for the next code block. 521 */ 522 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) { 523 spin_unlock(&fdp->fd_spin); 524 error = fdalloc(p, new, &newfd); 525 spin_lock(&fdp->fd_spin); 526 if (error) { 527 spin_unlock(&fdp->fd_spin); 528 fdrop(fp); 529 return (error); 530 } 531 /* 532 * Check for ripout 533 */ 534 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { 535 fsetfd_locked(fdp, NULL, newfd); 536 spin_unlock(&fdp->fd_spin); 537 fdrop(fp); 538 goto retry; 539 } 540 /* 541 * Check for expansion race 542 */ 543 if (type != DUP_VARIABLE && new != newfd) { 544 fsetfd_locked(fdp, NULL, newfd); 545 spin_unlock(&fdp->fd_spin); 546 fdrop(fp); 547 goto retry; 548 } 549 /* 550 * Check for ripout, newfd reused old (this case probably 551 * can't occur). 552 */ 553 if (old == newfd) { 554 fsetfd_locked(fdp, NULL, newfd); 555 spin_unlock(&fdp->fd_spin); 556 fdrop(fp); 557 goto retry; 558 } 559 new = newfd; 560 delfp = NULL; 561 } else { 562 if (fdp->fd_files[new].reserved) { 563 spin_unlock(&fdp->fd_spin); 564 fdrop(fp); 565 kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new); 566 tsleep(fdp, 0, "fdres", hz); 567 goto retry; 568 } 569 570 /* 571 * If the target descriptor was never allocated we have 572 * to allocate it. If it was we have to clean out the 573 * old descriptor. delfp inherits the ref from the 574 * descriptor table. 575 */ 576 delfp = fdp->fd_files[new].fp; 577 fdp->fd_files[new].fp = NULL; 578 fdp->fd_files[new].reserved = 1; 579 if (delfp == NULL) { 580 fdreserve_locked(fdp, new, 1); 581 if (new > fdp->fd_lastfile) 582 fdp->fd_lastfile = new; 583 } 584 585 } 586 587 /* 588 * NOTE: still holding an exclusive spinlock 589 */ 590 591 /* 592 * If a descriptor is being overwritten we may hve to tell 593 * fdfree() to sleep to ensure that all relevant process 594 * leaders can be traversed in closef(). 595 */ 596 if (delfp != NULL && p->p_fdtol != NULL) { 597 fdp->fd_holdleaderscount++; 598 holdleaders = 1; 599 } else { 600 holdleaders = 0; 601 } 602 KASSERT(delfp == NULL || type == DUP_FIXED, 603 ("dup() picked an open file")); 604 605 /* 606 * Duplicate the source descriptor, update lastfile. If the new 607 * descriptor was not allocated and we aren't replacing an existing 608 * descriptor we have to mark the descriptor as being in use. 609 * 610 * The fd_files[] array inherits fp's hold reference. 611 */ 612 fsetfd_locked(fdp, fp, new); 613 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; 614 spin_unlock(&fdp->fd_spin); 615 fdrop(fp); 616 *res = new; 617 618 /* 619 * If we dup'd over a valid file, we now own the reference to it 620 * and must dispose of it using closef() semantics (as if a 621 * close() were performed on it). 622 */ 623 if (delfp) { 624 if (SLIST_FIRST(&delfp->f_klist)) 625 knote_fdclose(delfp, fdp, new); 626 closef(delfp, p); 627 if (holdleaders) { 628 spin_lock(&fdp->fd_spin); 629 fdp->fd_holdleaderscount--; 630 if (fdp->fd_holdleaderscount == 0 && 631 fdp->fd_holdleaderswakeup != 0) { 632 fdp->fd_holdleaderswakeup = 0; 633 spin_unlock(&fdp->fd_spin); 634 wakeup(&fdp->fd_holdleaderscount); 635 } else { 636 spin_unlock(&fdp->fd_spin); 637 } 638 } 639 } 640 return (0); 641 } 642 643 /* 644 * If sigio is on the list associated with a process or process group, 645 * disable signalling from the device, remove sigio from the list and 646 * free sigio. 647 */ 648 void 649 funsetown(struct sigio *sigio) 650 { 651 if (sigio == NULL) 652 return; 653 crit_enter(); 654 *(sigio->sio_myref) = NULL; 655 crit_exit(); 656 if (sigio->sio_pgid < 0) { 657 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 658 sigio, sio_pgsigio); 659 } else /* if ((*sigiop)->sio_pgid > 0) */ { 660 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 661 sigio, sio_pgsigio); 662 } 663 crfree(sigio->sio_ucred); 664 kfree(sigio, M_SIGIO); 665 } 666 667 /* Free a list of sigio structures. */ 668 void 669 funsetownlst(struct sigiolst *sigiolst) 670 { 671 struct sigio *sigio; 672 673 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 674 funsetown(sigio); 675 } 676 677 /* 678 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 679 * 680 * After permission checking, add a sigio structure to the sigio list for 681 * the process or process group. 682 */ 683 int 684 fsetown(pid_t pgid, struct sigio **sigiop) 685 { 686 struct proc *proc; 687 struct pgrp *pgrp; 688 struct sigio *sigio; 689 690 if (pgid == 0) { 691 funsetown(*sigiop); 692 return (0); 693 } 694 if (pgid > 0) { 695 proc = pfind(pgid); 696 if (proc == NULL) 697 return (ESRCH); 698 699 /* 700 * Policy - Don't allow a process to FSETOWN a process 701 * in another session. 702 * 703 * Remove this test to allow maximum flexibility or 704 * restrict FSETOWN to the current process or process 705 * group for maximum safety. 706 */ 707 if (proc->p_session != curproc->p_session) 708 return (EPERM); 709 710 pgrp = NULL; 711 } else /* if (pgid < 0) */ { 712 pgrp = pgfind(-pgid); 713 if (pgrp == NULL) 714 return (ESRCH); 715 716 /* 717 * Policy - Don't allow a process to FSETOWN a process 718 * in another session. 719 * 720 * Remove this test to allow maximum flexibility or 721 * restrict FSETOWN to the current process or process 722 * group for maximum safety. 723 */ 724 if (pgrp->pg_session != curproc->p_session) 725 return (EPERM); 726 727 proc = NULL; 728 } 729 funsetown(*sigiop); 730 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); 731 if (pgid > 0) { 732 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 733 sigio->sio_proc = proc; 734 } else { 735 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 736 sigio->sio_pgrp = pgrp; 737 } 738 sigio->sio_pgid = pgid; 739 sigio->sio_ucred = crhold(curthread->td_ucred); 740 /* It would be convenient if p_ruid was in ucred. */ 741 sigio->sio_ruid = sigio->sio_ucred->cr_ruid; 742 sigio->sio_myref = sigiop; 743 crit_enter(); 744 *sigiop = sigio; 745 crit_exit(); 746 return (0); 747 } 748 749 /* 750 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 751 */ 752 pid_t 753 fgetown(struct sigio *sigio) 754 { 755 return (sigio != NULL ? sigio->sio_pgid : 0); 756 } 757 758 /* 759 * Close many file descriptors. 760 * 761 * MPSAFE 762 */ 763 int 764 sys_closefrom(struct closefrom_args *uap) 765 { 766 return(kern_closefrom(uap->fd)); 767 } 768 769 /* 770 * Close all file descriptors greater then or equal to fd 771 * 772 * MPSAFE 773 */ 774 int 775 kern_closefrom(int fd) 776 { 777 struct thread *td = curthread; 778 struct proc *p = td->td_proc; 779 struct filedesc *fdp; 780 781 KKASSERT(p); 782 fdp = p->p_fd; 783 784 if (fd < 0) 785 return (EINVAL); 786 787 /* 788 * NOTE: This function will skip unassociated descriptors and 789 * reserved descriptors that have not yet been assigned. 790 * fd_lastfile can change as a side effect of kern_close(). 791 */ 792 spin_lock(&fdp->fd_spin); 793 while (fd <= fdp->fd_lastfile) { 794 if (fdp->fd_files[fd].fp != NULL) { 795 spin_unlock(&fdp->fd_spin); 796 /* ok if this races another close */ 797 if (kern_close(fd) == EINTR) 798 return (EINTR); 799 spin_lock(&fdp->fd_spin); 800 } 801 ++fd; 802 } 803 spin_unlock(&fdp->fd_spin); 804 return (0); 805 } 806 807 /* 808 * Close a file descriptor. 809 * 810 * MPSAFE 811 */ 812 int 813 sys_close(struct close_args *uap) 814 { 815 return(kern_close(uap->fd)); 816 } 817 818 /* 819 * MPSAFE 820 */ 821 int 822 kern_close(int fd) 823 { 824 struct thread *td = curthread; 825 struct proc *p = td->td_proc; 826 struct filedesc *fdp; 827 struct file *fp; 828 int error; 829 int holdleaders; 830 831 KKASSERT(p); 832 fdp = p->p_fd; 833 834 spin_lock(&fdp->fd_spin); 835 if ((fp = funsetfd_locked(fdp, fd)) == NULL) { 836 spin_unlock(&fdp->fd_spin); 837 return (EBADF); 838 } 839 holdleaders = 0; 840 if (p->p_fdtol != NULL) { 841 /* 842 * Ask fdfree() to sleep to ensure that all relevant 843 * process leaders can be traversed in closef(). 844 */ 845 fdp->fd_holdleaderscount++; 846 holdleaders = 1; 847 } 848 849 /* 850 * we now hold the fp reference that used to be owned by the descriptor 851 * array. 852 */ 853 spin_unlock(&fdp->fd_spin); 854 if (SLIST_FIRST(&fp->f_klist)) 855 knote_fdclose(fp, fdp, fd); 856 error = closef(fp, p); 857 if (holdleaders) { 858 spin_lock(&fdp->fd_spin); 859 fdp->fd_holdleaderscount--; 860 if (fdp->fd_holdleaderscount == 0 && 861 fdp->fd_holdleaderswakeup != 0) { 862 fdp->fd_holdleaderswakeup = 0; 863 spin_unlock(&fdp->fd_spin); 864 wakeup(&fdp->fd_holdleaderscount); 865 } else { 866 spin_unlock(&fdp->fd_spin); 867 } 868 } 869 return (error); 870 } 871 872 /* 873 * shutdown_args(int fd, int how) 874 */ 875 int 876 kern_shutdown(int fd, int how) 877 { 878 struct thread *td = curthread; 879 struct proc *p = td->td_proc; 880 struct file *fp; 881 int error; 882 883 KKASSERT(p); 884 885 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 886 return (EBADF); 887 error = fo_shutdown(fp, how); 888 fdrop(fp); 889 890 return (error); 891 } 892 893 /* 894 * MPALMOSTSAFE 895 */ 896 int 897 sys_shutdown(struct shutdown_args *uap) 898 { 899 int error; 900 901 get_mplock(); 902 error = kern_shutdown(uap->s, uap->how); 903 rel_mplock(); 904 905 return (error); 906 } 907 908 /* 909 * MPSAFE 910 */ 911 int 912 kern_fstat(int fd, struct stat *ub) 913 { 914 struct thread *td = curthread; 915 struct proc *p = td->td_proc; 916 struct file *fp; 917 int error; 918 919 KKASSERT(p); 920 921 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 922 return (EBADF); 923 error = fo_stat(fp, ub, td->td_ucred); 924 fdrop(fp); 925 926 return (error); 927 } 928 929 /* 930 * Return status information about a file descriptor. 931 * 932 * MPSAFE 933 */ 934 int 935 sys_fstat(struct fstat_args *uap) 936 { 937 struct stat st; 938 int error; 939 940 error = kern_fstat(uap->fd, &st); 941 942 if (error == 0) 943 error = copyout(&st, uap->sb, sizeof(st)); 944 return (error); 945 } 946 947 /* 948 * Return pathconf information about a file descriptor. 949 * 950 * MPALMOSTSAFE 951 */ 952 int 953 sys_fpathconf(struct fpathconf_args *uap) 954 { 955 struct thread *td = curthread; 956 struct proc *p = td->td_proc; 957 struct file *fp; 958 struct vnode *vp; 959 int error = 0; 960 961 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 962 return (EBADF); 963 964 switch (fp->f_type) { 965 case DTYPE_PIPE: 966 case DTYPE_SOCKET: 967 if (uap->name != _PC_PIPE_BUF) { 968 error = EINVAL; 969 } else { 970 uap->sysmsg_result = PIPE_BUF; 971 error = 0; 972 } 973 break; 974 case DTYPE_FIFO: 975 case DTYPE_VNODE: 976 vp = (struct vnode *)fp->f_data; 977 get_mplock(); 978 error = VOP_PATHCONF(vp, uap->name, &uap->sysmsg_reg); 979 rel_mplock(); 980 break; 981 default: 982 error = EOPNOTSUPP; 983 break; 984 } 985 fdrop(fp); 986 return(error); 987 } 988 989 static int fdexpand; 990 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, 991 "Number of times a file table has been expanded"); 992 993 /* 994 * Grow the file table so it can hold through descriptor (want). 995 * 996 * The fdp's spinlock must be held exclusively on entry and may be held 997 * exclusively on return. The spinlock may be cycled by the routine. 998 * 999 * MPSAFE 1000 */ 1001 static void 1002 fdgrow_locked(struct filedesc *fdp, int want) 1003 { 1004 struct fdnode *newfiles; 1005 struct fdnode *oldfiles; 1006 int nf, extra; 1007 1008 nf = fdp->fd_nfiles; 1009 do { 1010 /* nf has to be of the form 2^n - 1 */ 1011 nf = 2 * nf + 1; 1012 } while (nf <= want); 1013 1014 spin_unlock(&fdp->fd_spin); 1015 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); 1016 spin_lock(&fdp->fd_spin); 1017 1018 /* 1019 * We could have raced another extend while we were not holding 1020 * the spinlock. 1021 */ 1022 if (fdp->fd_nfiles >= nf) { 1023 spin_unlock(&fdp->fd_spin); 1024 kfree(newfiles, M_FILEDESC); 1025 spin_lock(&fdp->fd_spin); 1026 return; 1027 } 1028 /* 1029 * Copy the existing ofile and ofileflags arrays 1030 * and zero the new portion of each array. 1031 */ 1032 extra = nf - fdp->fd_nfiles; 1033 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); 1034 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); 1035 1036 oldfiles = fdp->fd_files; 1037 fdp->fd_files = newfiles; 1038 fdp->fd_nfiles = nf; 1039 1040 if (oldfiles != fdp->fd_builtin_files) { 1041 spin_unlock(&fdp->fd_spin); 1042 kfree(oldfiles, M_FILEDESC); 1043 spin_lock(&fdp->fd_spin); 1044 } 1045 fdexpand++; 1046 } 1047 1048 /* 1049 * Number of nodes in right subtree, including the root. 1050 */ 1051 static __inline int 1052 right_subtree_size(int n) 1053 { 1054 return (n ^ (n | (n + 1))); 1055 } 1056 1057 /* 1058 * Bigger ancestor. 1059 */ 1060 static __inline int 1061 right_ancestor(int n) 1062 { 1063 return (n | (n + 1)); 1064 } 1065 1066 /* 1067 * Smaller ancestor. 1068 */ 1069 static __inline int 1070 left_ancestor(int n) 1071 { 1072 return ((n & (n + 1)) - 1); 1073 } 1074 1075 /* 1076 * Traverse the in-place binary tree buttom-up adjusting the allocation 1077 * count so scans can determine where free descriptors are located. 1078 * 1079 * MPSAFE - caller must be holding an exclusive spinlock on fdp 1080 */ 1081 static 1082 void 1083 fdreserve_locked(struct filedesc *fdp, int fd, int incr) 1084 { 1085 while (fd >= 0) { 1086 fdp->fd_files[fd].allocated += incr; 1087 KKASSERT(fdp->fd_files[fd].allocated >= 0); 1088 fd = left_ancestor(fd); 1089 } 1090 } 1091 1092 /* 1093 * Reserve a file descriptor for the process. If no error occurs, the 1094 * caller MUST at some point call fsetfd() or assign a file pointer 1095 * or dispose of the reservation. 1096 * 1097 * MPSAFE 1098 */ 1099 int 1100 fdalloc(struct proc *p, int want, int *result) 1101 { 1102 struct filedesc *fdp = p->p_fd; 1103 struct uidinfo *uip; 1104 int fd, rsize, rsum, node, lim; 1105 1106 /* 1107 * Check dtable size limit 1108 */ 1109 spin_lock(&p->p_limit->p_spin); 1110 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1111 lim = INT_MAX; 1112 else 1113 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1114 spin_unlock(&p->p_limit->p_spin); 1115 1116 if (lim > maxfilesperproc) 1117 lim = maxfilesperproc; 1118 if (lim < minfilesperproc) 1119 lim = minfilesperproc; 1120 if (want >= lim) 1121 return (EMFILE); 1122 1123 /* 1124 * Check that the user has not run out of descriptors (non-root only). 1125 * As a safety measure the dtable is allowed to have at least 1126 * minfilesperproc open fds regardless of the maxfilesperuser limit. 1127 */ 1128 if (p->p_ucred->cr_uid && fdp->fd_nfiles >= minfilesperproc) { 1129 uip = p->p_ucred->cr_uidinfo; 1130 if (uip->ui_openfiles > maxfilesperuser) { 1131 krateprintf(&krate_uidinfo, 1132 "Warning: user %d pid %d (%s) ran out of " 1133 "file descriptors (%d/%d)\n", 1134 p->p_ucred->cr_uid, (int)p->p_pid, 1135 p->p_comm, 1136 uip->ui_openfiles, maxfilesperuser); 1137 return(ENFILE); 1138 } 1139 } 1140 1141 /* 1142 * Grow the dtable if necessary 1143 */ 1144 spin_lock(&fdp->fd_spin); 1145 if (want >= fdp->fd_nfiles) 1146 fdgrow_locked(fdp, want); 1147 1148 /* 1149 * Search for a free descriptor starting at the higher 1150 * of want or fd_freefile. If that fails, consider 1151 * expanding the ofile array. 1152 * 1153 * NOTE! the 'allocated' field is a cumulative recursive allocation 1154 * count. If we happen to see a value of 0 then we can shortcut 1155 * our search. Otherwise we run through through the tree going 1156 * down branches we know have free descriptor(s) until we hit a 1157 * leaf node. The leaf node will be free but will not necessarily 1158 * have an allocated field of 0. 1159 */ 1160 retry: 1161 /* move up the tree looking for a subtree with a free node */ 1162 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); 1163 fd = right_ancestor(fd)) { 1164 if (fdp->fd_files[fd].allocated == 0) 1165 goto found; 1166 1167 rsize = right_subtree_size(fd); 1168 if (fdp->fd_files[fd].allocated == rsize) 1169 continue; /* right subtree full */ 1170 1171 /* 1172 * Free fd is in the right subtree of the tree rooted at fd. 1173 * Call that subtree R. Look for the smallest (leftmost) 1174 * subtree of R with an unallocated fd: continue moving 1175 * down the left branch until encountering a full left 1176 * subtree, then move to the right. 1177 */ 1178 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 1179 node = fd + rsize; 1180 rsum += fdp->fd_files[node].allocated; 1181 if (fdp->fd_files[fd].allocated == rsum + rsize) { 1182 fd = node; /* move to the right */ 1183 if (fdp->fd_files[node].allocated == 0) 1184 goto found; 1185 rsum = 0; 1186 } 1187 } 1188 goto found; 1189 } 1190 1191 /* 1192 * No space in current array. Expand? 1193 */ 1194 if (fdp->fd_nfiles >= lim) { 1195 spin_unlock(&fdp->fd_spin); 1196 return (EMFILE); 1197 } 1198 fdgrow_locked(fdp, want); 1199 goto retry; 1200 1201 found: 1202 KKASSERT(fd < fdp->fd_nfiles); 1203 if (fd > fdp->fd_lastfile) 1204 fdp->fd_lastfile = fd; 1205 if (want <= fdp->fd_freefile) 1206 fdp->fd_freefile = fd; 1207 *result = fd; 1208 KKASSERT(fdp->fd_files[fd].fp == NULL); 1209 KKASSERT(fdp->fd_files[fd].reserved == 0); 1210 fdp->fd_files[fd].fileflags = 0; 1211 fdp->fd_files[fd].reserved = 1; 1212 fdreserve_locked(fdp, fd, 1); 1213 spin_unlock(&fdp->fd_spin); 1214 return (0); 1215 } 1216 1217 /* 1218 * Check to see whether n user file descriptors 1219 * are available to the process p. 1220 * 1221 * MPSAFE 1222 */ 1223 int 1224 fdavail(struct proc *p, int n) 1225 { 1226 struct filedesc *fdp = p->p_fd; 1227 struct fdnode *fdnode; 1228 int i, lim, last; 1229 1230 spin_lock(&p->p_limit->p_spin); 1231 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1232 lim = INT_MAX; 1233 else 1234 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1235 spin_unlock(&p->p_limit->p_spin); 1236 1237 if (lim > maxfilesperproc) 1238 lim = maxfilesperproc; 1239 if (lim < minfilesperproc) 1240 lim = minfilesperproc; 1241 1242 spin_lock(&fdp->fd_spin); 1243 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { 1244 spin_unlock(&fdp->fd_spin); 1245 return (1); 1246 } 1247 last = min(fdp->fd_nfiles, lim); 1248 fdnode = &fdp->fd_files[fdp->fd_freefile]; 1249 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { 1250 if (fdnode->fp == NULL && --n <= 0) { 1251 spin_unlock(&fdp->fd_spin); 1252 return (1); 1253 } 1254 } 1255 spin_unlock(&fdp->fd_spin); 1256 return (0); 1257 } 1258 1259 /* 1260 * Revoke open descriptors referencing (f_data, f_type) 1261 * 1262 * Any revoke executed within a prison is only able to 1263 * revoke descriptors for processes within that prison. 1264 * 1265 * Returns 0 on success or an error code. 1266 */ 1267 struct fdrevoke_info { 1268 void *data; 1269 short type; 1270 short unused; 1271 int count; 1272 int intransit; 1273 struct ucred *cred; 1274 struct file *nfp; 1275 }; 1276 1277 static int fdrevoke_check_callback(struct file *fp, void *vinfo); 1278 static int fdrevoke_proc_callback(struct proc *p, void *vinfo); 1279 1280 int 1281 fdrevoke(void *f_data, short f_type, struct ucred *cred) 1282 { 1283 struct fdrevoke_info info; 1284 int error; 1285 1286 bzero(&info, sizeof(info)); 1287 info.data = f_data; 1288 info.type = f_type; 1289 info.cred = cred; 1290 error = falloc(NULL, &info.nfp, NULL); 1291 if (error) 1292 return (error); 1293 1294 /* 1295 * Scan the file pointer table once. dups do not dup file pointers, 1296 * only descriptors, so there is no leak. Set FREVOKED on the fps 1297 * being revoked. 1298 */ 1299 allfiles_scan_exclusive(fdrevoke_check_callback, &info); 1300 1301 /* 1302 * If any fps were marked track down the related descriptors 1303 * and close them. Any dup()s at this point will notice 1304 * the FREVOKED already set in the fp and do the right thing. 1305 * 1306 * Any fps with non-zero msgcounts (aka sent over a unix-domain 1307 * socket) bumped the intransit counter and will require a 1308 * scan. Races against fps leaving the socket are closed by 1309 * the socket code checking for FREVOKED. 1310 */ 1311 if (info.count) 1312 allproc_scan(fdrevoke_proc_callback, &info); 1313 if (info.intransit) 1314 unp_revoke_gc(info.nfp); 1315 fdrop(info.nfp); 1316 return(0); 1317 } 1318 1319 /* 1320 * Locate matching file pointers directly. 1321 * 1322 * WARNING: allfiles_scan_exclusive() holds a spinlock through these calls! 1323 */ 1324 static int 1325 fdrevoke_check_callback(struct file *fp, void *vinfo) 1326 { 1327 struct fdrevoke_info *info = vinfo; 1328 1329 /* 1330 * File pointers already flagged for revokation are skipped. 1331 */ 1332 if (fp->f_flag & FREVOKED) 1333 return(0); 1334 1335 /* 1336 * If revoking from a prison file pointers created outside of 1337 * that prison, or file pointers without creds, cannot be revoked. 1338 */ 1339 if (info->cred->cr_prison && 1340 (fp->f_cred == NULL || 1341 info->cred->cr_prison != fp->f_cred->cr_prison)) { 1342 return(0); 1343 } 1344 1345 /* 1346 * If the file pointer matches then mark it for revocation. The 1347 * flag is currently only used by unp_revoke_gc(). 1348 * 1349 * info->count is a heuristic and can race in a SMP environment. 1350 */ 1351 if (info->data == fp->f_data && info->type == fp->f_type) { 1352 atomic_set_int(&fp->f_flag, FREVOKED); 1353 info->count += fp->f_count; 1354 if (fp->f_msgcount) 1355 ++info->intransit; 1356 } 1357 return(0); 1358 } 1359 1360 /* 1361 * Locate matching file pointers via process descriptor tables. 1362 */ 1363 static int 1364 fdrevoke_proc_callback(struct proc *p, void *vinfo) 1365 { 1366 struct fdrevoke_info *info = vinfo; 1367 struct filedesc *fdp; 1368 struct file *fp; 1369 int n; 1370 1371 if (p->p_stat == SIDL || p->p_stat == SZOMB) 1372 return(0); 1373 if (info->cred->cr_prison && 1374 info->cred->cr_prison != p->p_ucred->cr_prison) { 1375 return(0); 1376 } 1377 1378 /* 1379 * If the controlling terminal of the process matches the 1380 * vnode being revoked we clear the controlling terminal. 1381 * 1382 * The normal spec_close() may not catch this because it 1383 * uses curproc instead of p. 1384 */ 1385 if (p->p_session && info->type == DTYPE_VNODE && 1386 info->data == p->p_session->s_ttyvp) { 1387 p->p_session->s_ttyvp = NULL; 1388 vrele(info->data); 1389 } 1390 1391 /* 1392 * Softref the fdp to prevent it from being destroyed 1393 */ 1394 spin_lock(&p->p_spin); 1395 if ((fdp = p->p_fd) == NULL) { 1396 spin_unlock(&p->p_spin); 1397 return(0); 1398 } 1399 atomic_add_int(&fdp->fd_softrefs, 1); 1400 spin_unlock(&p->p_spin); 1401 1402 /* 1403 * Locate and close any matching file descriptors. 1404 */ 1405 spin_lock(&fdp->fd_spin); 1406 for (n = 0; n < fdp->fd_nfiles; ++n) { 1407 if ((fp = fdp->fd_files[n].fp) == NULL) 1408 continue; 1409 if (fp->f_flag & FREVOKED) { 1410 fhold(info->nfp); 1411 fdp->fd_files[n].fp = info->nfp; 1412 spin_unlock(&fdp->fd_spin); 1413 knote_fdclose(fp, fdp, n); /* XXX */ 1414 closef(fp, p); 1415 spin_lock(&fdp->fd_spin); 1416 --info->count; 1417 } 1418 } 1419 spin_unlock(&fdp->fd_spin); 1420 atomic_subtract_int(&fdp->fd_softrefs, 1); 1421 return(0); 1422 } 1423 1424 /* 1425 * falloc: 1426 * Create a new open file structure and reserve a file decriptor 1427 * for the process that refers to it. 1428 * 1429 * Root creds are checked using lp, or assumed if lp is NULL. If 1430 * resultfd is non-NULL then lp must also be non-NULL. No file 1431 * descriptor is reserved (and no process context is needed) if 1432 * resultfd is NULL. 1433 * 1434 * A file pointer with a refcount of 1 is returned. Note that the 1435 * file pointer is NOT associated with the descriptor. If falloc 1436 * returns success, fsetfd() MUST be called to either associate the 1437 * file pointer or clear the reservation. 1438 * 1439 * MPSAFE 1440 */ 1441 int 1442 falloc(struct lwp *lp, struct file **resultfp, int *resultfd) 1443 { 1444 static struct timeval lastfail; 1445 static int curfail; 1446 struct file *fp; 1447 struct ucred *cred = lp ? lp->lwp_thread->td_ucred : proc0.p_ucred; 1448 int error; 1449 1450 fp = NULL; 1451 1452 /* 1453 * Handle filetable full issues and root overfill. 1454 */ 1455 if (nfiles >= maxfiles - maxfilesrootres && 1456 (cred->cr_ruid != 0 || nfiles >= maxfiles)) { 1457 if (ppsratecheck(&lastfail, &curfail, 1)) { 1458 kprintf("kern.maxfiles limit exceeded by uid %d, " 1459 "please see tuning(7).\n", 1460 cred->cr_ruid); 1461 } 1462 error = ENFILE; 1463 goto done; 1464 } 1465 1466 /* 1467 * Allocate a new file descriptor. 1468 */ 1469 fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 1470 spin_init(&fp->f_spin); 1471 SLIST_INIT(&fp->f_klist); 1472 fp->f_count = 1; 1473 fp->f_ops = &badfileops; 1474 fp->f_seqcount = 1; 1475 fsetcred(fp, cred); 1476 spin_lock(&filehead_spin); 1477 nfiles++; 1478 LIST_INSERT_HEAD(&filehead, fp, f_list); 1479 spin_unlock(&filehead_spin); 1480 if (resultfd) { 1481 if ((error = fdalloc(lp->lwp_proc, 0, resultfd)) != 0) { 1482 fdrop(fp); 1483 fp = NULL; 1484 } 1485 } else { 1486 error = 0; 1487 } 1488 done: 1489 *resultfp = fp; 1490 return (error); 1491 } 1492 1493 /* 1494 * Check for races against a file descriptor by determining that the 1495 * file pointer is still associated with the specified file descriptor, 1496 * and a close is not currently in progress. 1497 * 1498 * MPSAFE 1499 */ 1500 int 1501 checkfdclosed(struct filedesc *fdp, int fd, struct file *fp) 1502 { 1503 int error; 1504 1505 spin_lock(&fdp->fd_spin); 1506 if ((unsigned)fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) 1507 error = EBADF; 1508 else 1509 error = 0; 1510 spin_unlock(&fdp->fd_spin); 1511 return (error); 1512 } 1513 1514 /* 1515 * Associate a file pointer with a previously reserved file descriptor. 1516 * This function always succeeds. 1517 * 1518 * If fp is NULL, the file descriptor is returned to the pool. 1519 */ 1520 1521 /* 1522 * MPSAFE (exclusive spinlock must be held on call) 1523 */ 1524 static void 1525 fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) 1526 { 1527 KKASSERT((unsigned)fd < fdp->fd_nfiles); 1528 KKASSERT(fdp->fd_files[fd].reserved != 0); 1529 if (fp) { 1530 fhold(fp); 1531 fdp->fd_files[fd].fp = fp; 1532 fdp->fd_files[fd].reserved = 0; 1533 } else { 1534 fdp->fd_files[fd].reserved = 0; 1535 fdreserve_locked(fdp, fd, -1); 1536 fdfixup_locked(fdp, fd); 1537 } 1538 } 1539 1540 /* 1541 * MPSAFE 1542 */ 1543 void 1544 fsetfd(struct filedesc *fdp, struct file *fp, int fd) 1545 { 1546 spin_lock(&fdp->fd_spin); 1547 fsetfd_locked(fdp, fp, fd); 1548 spin_unlock(&fdp->fd_spin); 1549 } 1550 1551 /* 1552 * MPSAFE (exclusive spinlock must be held on call) 1553 */ 1554 static 1555 struct file * 1556 funsetfd_locked(struct filedesc *fdp, int fd) 1557 { 1558 struct file *fp; 1559 1560 if ((unsigned)fd >= fdp->fd_nfiles) 1561 return (NULL); 1562 if ((fp = fdp->fd_files[fd].fp) == NULL) 1563 return (NULL); 1564 fdp->fd_files[fd].fp = NULL; 1565 fdp->fd_files[fd].fileflags = 0; 1566 1567 fdreserve_locked(fdp, fd, -1); 1568 fdfixup_locked(fdp, fd); 1569 return(fp); 1570 } 1571 1572 /* 1573 * MPSAFE 1574 */ 1575 int 1576 fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) 1577 { 1578 int error; 1579 1580 spin_lock(&fdp->fd_spin); 1581 if (((u_int)fd) >= fdp->fd_nfiles) { 1582 error = EBADF; 1583 } else if (fdp->fd_files[fd].fp == NULL) { 1584 error = EBADF; 1585 } else { 1586 *flagsp = fdp->fd_files[fd].fileflags; 1587 error = 0; 1588 } 1589 spin_unlock(&fdp->fd_spin); 1590 return (error); 1591 } 1592 1593 /* 1594 * MPSAFE 1595 */ 1596 int 1597 fsetfdflags(struct filedesc *fdp, int fd, int add_flags) 1598 { 1599 int error; 1600 1601 spin_lock(&fdp->fd_spin); 1602 if (((u_int)fd) >= fdp->fd_nfiles) { 1603 error = EBADF; 1604 } else if (fdp->fd_files[fd].fp == NULL) { 1605 error = EBADF; 1606 } else { 1607 fdp->fd_files[fd].fileflags |= add_flags; 1608 error = 0; 1609 } 1610 spin_unlock(&fdp->fd_spin); 1611 return (error); 1612 } 1613 1614 /* 1615 * MPSAFE 1616 */ 1617 int 1618 fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) 1619 { 1620 int error; 1621 1622 spin_lock(&fdp->fd_spin); 1623 if (((u_int)fd) >= fdp->fd_nfiles) { 1624 error = EBADF; 1625 } else if (fdp->fd_files[fd].fp == NULL) { 1626 error = EBADF; 1627 } else { 1628 fdp->fd_files[fd].fileflags &= ~rem_flags; 1629 error = 0; 1630 } 1631 spin_unlock(&fdp->fd_spin); 1632 return (error); 1633 } 1634 1635 /* 1636 * Set/Change/Clear the creds for a fp and synchronize the uidinfo. 1637 */ 1638 void 1639 fsetcred(struct file *fp, struct ucred *ncr) 1640 { 1641 struct ucred *ocr; 1642 struct uidinfo *uip; 1643 1644 ocr = fp->f_cred; 1645 if (ocr == NULL || ncr == NULL || ocr->cr_uidinfo != ncr->cr_uidinfo) { 1646 if (ocr) { 1647 uip = ocr->cr_uidinfo; 1648 atomic_add_int(&uip->ui_openfiles, -1); 1649 } 1650 if (ncr) { 1651 uip = ncr->cr_uidinfo; 1652 atomic_add_int(&uip->ui_openfiles, 1); 1653 } 1654 } 1655 if (ncr) 1656 crhold(ncr); 1657 fp->f_cred = ncr; 1658 if (ocr) 1659 crfree(ocr); 1660 } 1661 1662 /* 1663 * Free a file descriptor. 1664 */ 1665 static 1666 void 1667 ffree(struct file *fp) 1668 { 1669 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 1670 spin_lock(&filehead_spin); 1671 LIST_REMOVE(fp, f_list); 1672 nfiles--; 1673 spin_unlock(&filehead_spin); 1674 fsetcred(fp, NULL); 1675 if (fp->f_nchandle.ncp) 1676 cache_drop(&fp->f_nchandle); 1677 kfree(fp, M_FILE); 1678 } 1679 1680 /* 1681 * called from init_main, initialize filedesc0 for proc0. 1682 */ 1683 void 1684 fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) 1685 { 1686 p0->p_fd = fdp0; 1687 p0->p_fdtol = NULL; 1688 fdp0->fd_refcnt = 1; 1689 fdp0->fd_cmask = cmask; 1690 fdp0->fd_files = fdp0->fd_builtin_files; 1691 fdp0->fd_nfiles = NDFILE; 1692 fdp0->fd_lastfile = -1; 1693 spin_init(&fdp0->fd_spin); 1694 } 1695 1696 /* 1697 * Build a new filedesc structure. 1698 * 1699 * NOT MPSAFE (vref) 1700 */ 1701 struct filedesc * 1702 fdinit(struct proc *p) 1703 { 1704 struct filedesc *newfdp; 1705 struct filedesc *fdp = p->p_fd; 1706 1707 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); 1708 spin_lock(&fdp->fd_spin); 1709 if (fdp->fd_cdir) { 1710 newfdp->fd_cdir = fdp->fd_cdir; 1711 vref(newfdp->fd_cdir); 1712 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1713 } 1714 1715 /* 1716 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 1717 * proc0, but should unconditionally exist in other processes. 1718 */ 1719 if (fdp->fd_rdir) { 1720 newfdp->fd_rdir = fdp->fd_rdir; 1721 vref(newfdp->fd_rdir); 1722 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1723 } 1724 if (fdp->fd_jdir) { 1725 newfdp->fd_jdir = fdp->fd_jdir; 1726 vref(newfdp->fd_jdir); 1727 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1728 } 1729 spin_unlock(&fdp->fd_spin); 1730 1731 /* Create the file descriptor table. */ 1732 newfdp->fd_refcnt = 1; 1733 newfdp->fd_cmask = cmask; 1734 newfdp->fd_files = newfdp->fd_builtin_files; 1735 newfdp->fd_nfiles = NDFILE; 1736 newfdp->fd_lastfile = -1; 1737 spin_init(&newfdp->fd_spin); 1738 1739 return (newfdp); 1740 } 1741 1742 /* 1743 * Share a filedesc structure. 1744 * 1745 * MPSAFE 1746 */ 1747 struct filedesc * 1748 fdshare(struct proc *p) 1749 { 1750 struct filedesc *fdp; 1751 1752 fdp = p->p_fd; 1753 spin_lock(&fdp->fd_spin); 1754 fdp->fd_refcnt++; 1755 spin_unlock(&fdp->fd_spin); 1756 return (fdp); 1757 } 1758 1759 /* 1760 * Copy a filedesc structure. 1761 * 1762 * MPSAFE 1763 */ 1764 struct filedesc * 1765 fdcopy(struct proc *p) 1766 { 1767 struct filedesc *fdp = p->p_fd; 1768 struct filedesc *newfdp; 1769 struct fdnode *fdnode; 1770 int i; 1771 int ni; 1772 1773 /* 1774 * Certain daemons might not have file descriptors. 1775 */ 1776 if (fdp == NULL) 1777 return (NULL); 1778 1779 /* 1780 * Allocate the new filedesc and fd_files[] array. This can race 1781 * with operations by other threads on the fdp so we have to be 1782 * careful. 1783 */ 1784 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK | M_ZERO); 1785 again: 1786 spin_lock(&fdp->fd_spin); 1787 if (fdp->fd_lastfile < NDFILE) { 1788 newfdp->fd_files = newfdp->fd_builtin_files; 1789 i = NDFILE; 1790 } else { 1791 /* 1792 * We have to allocate (N^2-1) entries for our in-place 1793 * binary tree. Allow the table to shrink. 1794 */ 1795 i = fdp->fd_nfiles; 1796 ni = (i - 1) / 2; 1797 while (ni > fdp->fd_lastfile && ni > NDFILE) { 1798 i = ni; 1799 ni = (i - 1) / 2; 1800 } 1801 spin_unlock(&fdp->fd_spin); 1802 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), 1803 M_FILEDESC, M_WAITOK | M_ZERO); 1804 1805 /* 1806 * Check for race, retry 1807 */ 1808 spin_lock(&fdp->fd_spin); 1809 if (i <= fdp->fd_lastfile) { 1810 spin_unlock(&fdp->fd_spin); 1811 kfree(newfdp->fd_files, M_FILEDESC); 1812 goto again; 1813 } 1814 } 1815 1816 /* 1817 * Dup the remaining fields. vref() and cache_hold() can be 1818 * safely called while holding the read spinlock on fdp. 1819 * 1820 * The read spinlock on fdp is still being held. 1821 * 1822 * NOTE: vref and cache_hold calls for the case where the vnode 1823 * or cache entry already has at least one ref may be called 1824 * while holding spin locks. 1825 */ 1826 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { 1827 vref(newfdp->fd_cdir); 1828 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1829 } 1830 /* 1831 * We must check for fd_rdir here, at least for now because 1832 * the init process is created before we have access to the 1833 * rootvode to take a reference to it. 1834 */ 1835 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { 1836 vref(newfdp->fd_rdir); 1837 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1838 } 1839 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { 1840 vref(newfdp->fd_jdir); 1841 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1842 } 1843 newfdp->fd_refcnt = 1; 1844 newfdp->fd_nfiles = i; 1845 newfdp->fd_lastfile = fdp->fd_lastfile; 1846 newfdp->fd_freefile = fdp->fd_freefile; 1847 newfdp->fd_cmask = fdp->fd_cmask; 1848 spin_init(&newfdp->fd_spin); 1849 1850 /* 1851 * Copy the descriptor table through (i). This also copies the 1852 * allocation state. Then go through and ref the file pointers 1853 * and clean up any KQ descriptors. 1854 * 1855 * kq descriptors cannot be copied. Since we haven't ref'd the 1856 * copied files yet we can ignore the return value from funsetfd(). 1857 * 1858 * The read spinlock on fdp is still being held. 1859 */ 1860 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); 1861 for (i = 0 ; i < newfdp->fd_nfiles; ++i) { 1862 fdnode = &newfdp->fd_files[i]; 1863 if (fdnode->reserved) { 1864 fdreserve_locked(newfdp, i, -1); 1865 fdnode->reserved = 0; 1866 fdfixup_locked(newfdp, i); 1867 } else if (fdnode->fp) { 1868 if (fdnode->fp->f_type == DTYPE_KQUEUE) { 1869 (void)funsetfd_locked(newfdp, i); 1870 } else { 1871 fhold(fdnode->fp); 1872 } 1873 } 1874 } 1875 spin_unlock(&fdp->fd_spin); 1876 return (newfdp); 1877 } 1878 1879 /* 1880 * Release a filedesc structure. 1881 * 1882 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) 1883 */ 1884 void 1885 fdfree(struct proc *p, struct filedesc *repl) 1886 { 1887 struct filedesc *fdp; 1888 struct fdnode *fdnode; 1889 int i; 1890 struct filedesc_to_leader *fdtol; 1891 struct file *fp; 1892 struct vnode *vp; 1893 struct flock lf; 1894 1895 /* 1896 * Certain daemons might not have file descriptors. 1897 */ 1898 fdp = p->p_fd; 1899 if (fdp == NULL) { 1900 p->p_fd = repl; 1901 return; 1902 } 1903 1904 /* 1905 * Severe messing around to follow. 1906 */ 1907 spin_lock(&fdp->fd_spin); 1908 1909 /* Check for special need to clear POSIX style locks */ 1910 fdtol = p->p_fdtol; 1911 if (fdtol != NULL) { 1912 KASSERT(fdtol->fdl_refcount > 0, 1913 ("filedesc_to_refcount botch: fdl_refcount=%d", 1914 fdtol->fdl_refcount)); 1915 if (fdtol->fdl_refcount == 1 && 1916 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1917 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1918 fdnode = &fdp->fd_files[i]; 1919 if (fdnode->fp == NULL || 1920 fdnode->fp->f_type != DTYPE_VNODE) { 1921 continue; 1922 } 1923 fp = fdnode->fp; 1924 fhold(fp); 1925 spin_unlock(&fdp->fd_spin); 1926 1927 lf.l_whence = SEEK_SET; 1928 lf.l_start = 0; 1929 lf.l_len = 0; 1930 lf.l_type = F_UNLCK; 1931 vp = (struct vnode *)fp->f_data; 1932 (void) VOP_ADVLOCK(vp, 1933 (caddr_t)p->p_leader, 1934 F_UNLCK, 1935 &lf, 1936 F_POSIX); 1937 fdrop(fp); 1938 spin_lock(&fdp->fd_spin); 1939 } 1940 } 1941 retry: 1942 if (fdtol->fdl_refcount == 1) { 1943 if (fdp->fd_holdleaderscount > 0 && 1944 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1945 /* 1946 * close() or do_dup() has cleared a reference 1947 * in a shared file descriptor table. 1948 */ 1949 fdp->fd_holdleaderswakeup = 1; 1950 ssleep(&fdp->fd_holdleaderscount, 1951 &fdp->fd_spin, 0, "fdlhold", 0); 1952 goto retry; 1953 } 1954 if (fdtol->fdl_holdcount > 0) { 1955 /* 1956 * Ensure that fdtol->fdl_leader 1957 * remains valid in closef(). 1958 */ 1959 fdtol->fdl_wakeup = 1; 1960 ssleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); 1961 goto retry; 1962 } 1963 } 1964 fdtol->fdl_refcount--; 1965 if (fdtol->fdl_refcount == 0 && 1966 fdtol->fdl_holdcount == 0) { 1967 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1968 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1969 } else { 1970 fdtol = NULL; 1971 } 1972 p->p_fdtol = NULL; 1973 if (fdtol != NULL) { 1974 spin_unlock(&fdp->fd_spin); 1975 kfree(fdtol, M_FILEDESC_TO_LEADER); 1976 spin_lock(&fdp->fd_spin); 1977 } 1978 } 1979 if (--fdp->fd_refcnt > 0) { 1980 spin_unlock(&fdp->fd_spin); 1981 spin_lock(&p->p_spin); 1982 p->p_fd = repl; 1983 spin_unlock(&p->p_spin); 1984 return; 1985 } 1986 1987 /* 1988 * Even though we are the last reference to the structure allproc 1989 * scans may still reference the structure. Maintain proper 1990 * locks until we can replace p->p_fd. 1991 * 1992 * Also note that kqueue's closef still needs to reference the 1993 * fdp via p->p_fd, so we have to close the descriptors before 1994 * we replace p->p_fd. 1995 */ 1996 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1997 if (fdp->fd_files[i].fp) { 1998 fp = funsetfd_locked(fdp, i); 1999 if (fp) { 2000 spin_unlock(&fdp->fd_spin); 2001 if (SLIST_FIRST(&fp->f_klist)) 2002 knote_fdclose(fp, fdp, i); 2003 closef(fp, p); 2004 spin_lock(&fdp->fd_spin); 2005 } 2006 } 2007 } 2008 spin_unlock(&fdp->fd_spin); 2009 2010 /* 2011 * Interlock against an allproc scan operations (typically frevoke). 2012 */ 2013 spin_lock(&p->p_spin); 2014 p->p_fd = repl; 2015 spin_unlock(&p->p_spin); 2016 2017 /* 2018 * Wait for any softrefs to go away. This race rarely occurs so 2019 * we can use a non-critical-path style poll/sleep loop. The 2020 * race only occurs against allproc scans. 2021 * 2022 * No new softrefs can occur with the fdp disconnected from the 2023 * process. 2024 */ 2025 if (fdp->fd_softrefs) { 2026 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid); 2027 while (fdp->fd_softrefs) 2028 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1); 2029 } 2030 2031 if (fdp->fd_files != fdp->fd_builtin_files) 2032 kfree(fdp->fd_files, M_FILEDESC); 2033 if (fdp->fd_cdir) { 2034 cache_drop(&fdp->fd_ncdir); 2035 vrele(fdp->fd_cdir); 2036 } 2037 if (fdp->fd_rdir) { 2038 cache_drop(&fdp->fd_nrdir); 2039 vrele(fdp->fd_rdir); 2040 } 2041 if (fdp->fd_jdir) { 2042 cache_drop(&fdp->fd_njdir); 2043 vrele(fdp->fd_jdir); 2044 } 2045 kfree(fdp, M_FILEDESC); 2046 } 2047 2048 /* 2049 * Retrieve and reference the file pointer associated with a descriptor. 2050 * 2051 * MPSAFE 2052 */ 2053 struct file * 2054 holdfp(struct filedesc *fdp, int fd, int flag) 2055 { 2056 struct file* fp; 2057 2058 spin_lock(&fdp->fd_spin); 2059 if (((u_int)fd) >= fdp->fd_nfiles) { 2060 fp = NULL; 2061 goto done; 2062 } 2063 if ((fp = fdp->fd_files[fd].fp) == NULL) 2064 goto done; 2065 if ((fp->f_flag & flag) == 0 && flag != -1) { 2066 fp = NULL; 2067 goto done; 2068 } 2069 fhold(fp); 2070 done: 2071 spin_unlock(&fdp->fd_spin); 2072 return (fp); 2073 } 2074 2075 /* 2076 * holdsock() - load the struct file pointer associated 2077 * with a socket into *fpp. If an error occurs, non-zero 2078 * will be returned and *fpp will be set to NULL. 2079 * 2080 * MPSAFE 2081 */ 2082 int 2083 holdsock(struct filedesc *fdp, int fd, struct file **fpp) 2084 { 2085 struct file *fp; 2086 int error; 2087 2088 spin_lock(&fdp->fd_spin); 2089 if ((unsigned)fd >= fdp->fd_nfiles) { 2090 error = EBADF; 2091 fp = NULL; 2092 goto done; 2093 } 2094 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2095 error = EBADF; 2096 goto done; 2097 } 2098 if (fp->f_type != DTYPE_SOCKET) { 2099 error = ENOTSOCK; 2100 goto done; 2101 } 2102 fhold(fp); 2103 error = 0; 2104 done: 2105 spin_unlock(&fdp->fd_spin); 2106 *fpp = fp; 2107 return (error); 2108 } 2109 2110 /* 2111 * Convert a user file descriptor to a held file pointer. 2112 * 2113 * MPSAFE 2114 */ 2115 int 2116 holdvnode(struct filedesc *fdp, int fd, struct file **fpp) 2117 { 2118 struct file *fp; 2119 int error; 2120 2121 spin_lock(&fdp->fd_spin); 2122 if ((unsigned)fd >= fdp->fd_nfiles) { 2123 error = EBADF; 2124 fp = NULL; 2125 goto done; 2126 } 2127 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2128 error = EBADF; 2129 goto done; 2130 } 2131 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2132 fp = NULL; 2133 error = EINVAL; 2134 goto done; 2135 } 2136 fhold(fp); 2137 error = 0; 2138 done: 2139 spin_unlock(&fdp->fd_spin); 2140 *fpp = fp; 2141 return (error); 2142 } 2143 2144 /* 2145 * For setugid programs, we don't want to people to use that setugidness 2146 * to generate error messages which write to a file which otherwise would 2147 * otherwise be off-limits to the process. 2148 * 2149 * This is a gross hack to plug the hole. A better solution would involve 2150 * a special vop or other form of generalized access control mechanism. We 2151 * go ahead and just reject all procfs file systems accesses as dangerous. 2152 * 2153 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 2154 * sufficient. We also don't for check setugidness since we know we are. 2155 */ 2156 static int 2157 is_unsafe(struct file *fp) 2158 { 2159 if (fp->f_type == DTYPE_VNODE && 2160 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 2161 return (1); 2162 return (0); 2163 } 2164 2165 /* 2166 * Make this setguid thing safe, if at all possible. 2167 * 2168 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2169 */ 2170 void 2171 setugidsafety(struct proc *p) 2172 { 2173 struct filedesc *fdp = p->p_fd; 2174 int i; 2175 2176 /* Certain daemons might not have file descriptors. */ 2177 if (fdp == NULL) 2178 return; 2179 2180 /* 2181 * note: fdp->fd_files may be reallocated out from under us while 2182 * we are blocked in a close. Be careful! 2183 */ 2184 for (i = 0; i <= fdp->fd_lastfile; i++) { 2185 if (i > 2) 2186 break; 2187 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { 2188 struct file *fp; 2189 2190 /* 2191 * NULL-out descriptor prior to close to avoid 2192 * a race while close blocks. 2193 */ 2194 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2195 knote_fdclose(fp, fdp, i); 2196 closef(fp, p); 2197 } 2198 } 2199 } 2200 } 2201 2202 /* 2203 * Close any files on exec? 2204 * 2205 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2206 */ 2207 void 2208 fdcloseexec(struct proc *p) 2209 { 2210 struct filedesc *fdp = p->p_fd; 2211 int i; 2212 2213 /* Certain daemons might not have file descriptors. */ 2214 if (fdp == NULL) 2215 return; 2216 2217 /* 2218 * We cannot cache fd_files since operations may block and rip 2219 * them out from under us. 2220 */ 2221 for (i = 0; i <= fdp->fd_lastfile; i++) { 2222 if (fdp->fd_files[i].fp != NULL && 2223 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { 2224 struct file *fp; 2225 2226 /* 2227 * NULL-out descriptor prior to close to avoid 2228 * a race while close blocks. 2229 */ 2230 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2231 knote_fdclose(fp, fdp, i); 2232 closef(fp, p); 2233 } 2234 } 2235 } 2236 } 2237 2238 /* 2239 * It is unsafe for set[ug]id processes to be started with file 2240 * descriptors 0..2 closed, as these descriptors are given implicit 2241 * significance in the Standard C library. fdcheckstd() will create a 2242 * descriptor referencing /dev/null for each of stdin, stdout, and 2243 * stderr that is not already open. 2244 * 2245 * NOT MPSAFE - calls falloc, vn_open, etc 2246 */ 2247 int 2248 fdcheckstd(struct lwp *lp) 2249 { 2250 struct nlookupdata nd; 2251 struct filedesc *fdp; 2252 struct file *fp; 2253 int retval; 2254 int i, error, flags, devnull; 2255 2256 fdp = lp->lwp_proc->p_fd; 2257 if (fdp == NULL) 2258 return (0); 2259 devnull = -1; 2260 error = 0; 2261 for (i = 0; i < 3; i++) { 2262 if (fdp->fd_files[i].fp != NULL) 2263 continue; 2264 if (devnull < 0) { 2265 if ((error = falloc(lp, &fp, &devnull)) != 0) 2266 break; 2267 2268 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 2269 NLC_FOLLOW|NLC_LOCKVP); 2270 flags = FREAD | FWRITE; 2271 if (error == 0) 2272 error = vn_open(&nd, fp, flags, 0); 2273 if (error == 0) 2274 fsetfd(fdp, fp, devnull); 2275 else 2276 fsetfd(fdp, NULL, devnull); 2277 fdrop(fp); 2278 nlookup_done(&nd); 2279 if (error) 2280 break; 2281 KKASSERT(i == devnull); 2282 } else { 2283 error = kern_dup(DUP_FIXED, devnull, i, &retval); 2284 if (error != 0) 2285 break; 2286 } 2287 } 2288 return (error); 2289 } 2290 2291 /* 2292 * Internal form of close. 2293 * Decrement reference count on file structure. 2294 * Note: td and/or p may be NULL when closing a file 2295 * that was being passed in a message. 2296 * 2297 * MPALMOSTSAFE - acquires mplock for VOP operations 2298 */ 2299 int 2300 closef(struct file *fp, struct proc *p) 2301 { 2302 struct vnode *vp; 2303 struct flock lf; 2304 struct filedesc_to_leader *fdtol; 2305 2306 if (fp == NULL) 2307 return (0); 2308 2309 /* 2310 * POSIX record locking dictates that any close releases ALL 2311 * locks owned by this process. This is handled by setting 2312 * a flag in the unlock to free ONLY locks obeying POSIX 2313 * semantics, and not to free BSD-style file locks. 2314 * If the descriptor was in a message, POSIX-style locks 2315 * aren't passed with the descriptor. 2316 */ 2317 if (p != NULL && fp->f_type == DTYPE_VNODE && 2318 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2319 ) { 2320 get_mplock(); 2321 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) { 2322 lf.l_whence = SEEK_SET; 2323 lf.l_start = 0; 2324 lf.l_len = 0; 2325 lf.l_type = F_UNLCK; 2326 vp = (struct vnode *)fp->f_data; 2327 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 2328 &lf, F_POSIX); 2329 } 2330 fdtol = p->p_fdtol; 2331 if (fdtol != NULL) { 2332 /* 2333 * Handle special case where file descriptor table 2334 * is shared between multiple process leaders. 2335 */ 2336 for (fdtol = fdtol->fdl_next; 2337 fdtol != p->p_fdtol; 2338 fdtol = fdtol->fdl_next) { 2339 if ((fdtol->fdl_leader->p_flag & 2340 P_ADVLOCK) == 0) 2341 continue; 2342 fdtol->fdl_holdcount++; 2343 lf.l_whence = SEEK_SET; 2344 lf.l_start = 0; 2345 lf.l_len = 0; 2346 lf.l_type = F_UNLCK; 2347 vp = (struct vnode *)fp->f_data; 2348 (void) VOP_ADVLOCK(vp, 2349 (caddr_t)fdtol->fdl_leader, 2350 F_UNLCK, &lf, F_POSIX); 2351 fdtol->fdl_holdcount--; 2352 if (fdtol->fdl_holdcount == 0 && 2353 fdtol->fdl_wakeup != 0) { 2354 fdtol->fdl_wakeup = 0; 2355 wakeup(fdtol); 2356 } 2357 } 2358 } 2359 rel_mplock(); 2360 } 2361 return (fdrop(fp)); 2362 } 2363 2364 /* 2365 * MPSAFE 2366 * 2367 * fhold() can only be called if f_count is already at least 1 (i.e. the 2368 * caller of fhold() already has a reference to the file pointer in some 2369 * manner or other). 2370 * 2371 * f_count is not spin-locked. Instead, atomic ops are used for 2372 * incrementing, decrementing, and handling the 1->0 transition. 2373 */ 2374 void 2375 fhold(struct file *fp) 2376 { 2377 atomic_add_int(&fp->f_count, 1); 2378 } 2379 2380 /* 2381 * fdrop() - drop a reference to a descriptor 2382 * 2383 * MPALMOSTSAFE - acquires mplock for final close sequence 2384 */ 2385 int 2386 fdrop(struct file *fp) 2387 { 2388 struct flock lf; 2389 struct vnode *vp; 2390 int error; 2391 2392 /* 2393 * A combined fetch and subtract is needed to properly detect 2394 * 1->0 transitions, otherwise two cpus dropping from a ref 2395 * count of 2 might both try to run the 1->0 code. 2396 */ 2397 if (atomic_fetchadd_int(&fp->f_count, -1) > 1) 2398 return (0); 2399 2400 KKASSERT(SLIST_FIRST(&fp->f_klist) == NULL); 2401 get_mplock(); 2402 2403 /* 2404 * The last reference has gone away, we own the fp structure free 2405 * and clear. 2406 */ 2407 if (fp->f_count < 0) 2408 panic("fdrop: count < 0"); 2409 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && 2410 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2411 ) { 2412 lf.l_whence = SEEK_SET; 2413 lf.l_start = 0; 2414 lf.l_len = 0; 2415 lf.l_type = F_UNLCK; 2416 vp = (struct vnode *)fp->f_data; 2417 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2418 } 2419 if (fp->f_ops != &badfileops) 2420 error = fo_close(fp); 2421 else 2422 error = 0; 2423 ffree(fp); 2424 rel_mplock(); 2425 return (error); 2426 } 2427 2428 /* 2429 * Apply an advisory lock on a file descriptor. 2430 * 2431 * Just attempt to get a record lock of the requested type on 2432 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2433 * 2434 * MPALMOSTSAFE 2435 */ 2436 int 2437 sys_flock(struct flock_args *uap) 2438 { 2439 struct proc *p = curproc; 2440 struct file *fp; 2441 struct vnode *vp; 2442 struct flock lf; 2443 int error; 2444 2445 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 2446 return (EBADF); 2447 get_mplock(); 2448 if (fp->f_type != DTYPE_VNODE) { 2449 error = EOPNOTSUPP; 2450 goto done; 2451 } 2452 vp = (struct vnode *)fp->f_data; 2453 lf.l_whence = SEEK_SET; 2454 lf.l_start = 0; 2455 lf.l_len = 0; 2456 if (uap->how & LOCK_UN) { 2457 lf.l_type = F_UNLCK; 2458 fp->f_flag &= ~FHASLOCK; 2459 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2460 goto done; 2461 } 2462 if (uap->how & LOCK_EX) 2463 lf.l_type = F_WRLCK; 2464 else if (uap->how & LOCK_SH) 2465 lf.l_type = F_RDLCK; 2466 else { 2467 error = EBADF; 2468 goto done; 2469 } 2470 fp->f_flag |= FHASLOCK; 2471 if (uap->how & LOCK_NB) 2472 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); 2473 else 2474 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); 2475 done: 2476 rel_mplock(); 2477 fdrop(fp); 2478 return (error); 2479 } 2480 2481 /* 2482 * File Descriptor pseudo-device driver (/dev/fd/). 2483 * 2484 * Opening minor device N dup()s the file (if any) connected to file 2485 * descriptor N belonging to the calling process. Note that this driver 2486 * consists of only the ``open()'' routine, because all subsequent 2487 * references to this file will be direct to the other driver. 2488 */ 2489 static int 2490 fdopen(struct dev_open_args *ap) 2491 { 2492 thread_t td = curthread; 2493 2494 KKASSERT(td->td_lwp != NULL); 2495 2496 /* 2497 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the 2498 * the file descriptor being sought for duplication. The error 2499 * return ensures that the vnode for this device will be released 2500 * by vn_open. Open will detect this special error and take the 2501 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2502 * will simply report the error. 2503 */ 2504 td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev); 2505 return (ENODEV); 2506 } 2507 2508 /* 2509 * The caller has reserved the file descriptor dfd for us. On success we 2510 * must fsetfd() it. On failure the caller will clean it up. 2511 * 2512 * MPSAFE 2513 */ 2514 int 2515 dupfdopen(struct filedesc *fdp, int dfd, int sfd, int mode, int error) 2516 { 2517 struct file *wfp; 2518 struct file *xfp; 2519 int werror; 2520 2521 if ((wfp = holdfp(fdp, sfd, -1)) == NULL) 2522 return (EBADF); 2523 2524 /* 2525 * Close a revoke/dup race. Duping a descriptor marked as revoked 2526 * will dup a dummy descriptor instead of the real one. 2527 */ 2528 if (wfp->f_flag & FREVOKED) { 2529 kprintf("Warning: attempt to dup() a revoked descriptor\n"); 2530 fdrop(wfp); 2531 wfp = NULL; 2532 werror = falloc(NULL, &wfp, NULL); 2533 if (werror) 2534 return (werror); 2535 } 2536 2537 /* 2538 * There are two cases of interest here. 2539 * 2540 * For ENODEV simply dup sfd to file descriptor dfd and return. 2541 * 2542 * For ENXIO steal away the file structure from sfd and store it 2543 * dfd. sfd is effectively closed by this operation. 2544 * 2545 * Any other error code is just returned. 2546 */ 2547 switch (error) { 2548 case ENODEV: 2549 /* 2550 * Check that the mode the file is being opened for is a 2551 * subset of the mode of the existing descriptor. 2552 */ 2553 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2554 error = EACCES; 2555 break; 2556 } 2557 spin_lock(&fdp->fd_spin); 2558 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2559 fsetfd_locked(fdp, wfp, dfd); 2560 spin_unlock(&fdp->fd_spin); 2561 error = 0; 2562 break; 2563 case ENXIO: 2564 /* 2565 * Steal away the file pointer from dfd, and stuff it into indx. 2566 */ 2567 spin_lock(&fdp->fd_spin); 2568 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2569 fsetfd(fdp, wfp, dfd); 2570 if ((xfp = funsetfd_locked(fdp, sfd)) != NULL) { 2571 spin_unlock(&fdp->fd_spin); 2572 fdrop(xfp); 2573 } else { 2574 spin_unlock(&fdp->fd_spin); 2575 } 2576 error = 0; 2577 break; 2578 default: 2579 break; 2580 } 2581 fdrop(wfp); 2582 return (error); 2583 } 2584 2585 /* 2586 * NOT MPSAFE - I think these refer to a common file descriptor table 2587 * and we need to spinlock that to link fdtol in. 2588 */ 2589 struct filedesc_to_leader * 2590 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2591 struct proc *leader) 2592 { 2593 struct filedesc_to_leader *fdtol; 2594 2595 fdtol = kmalloc(sizeof(struct filedesc_to_leader), 2596 M_FILEDESC_TO_LEADER, M_WAITOK); 2597 fdtol->fdl_refcount = 1; 2598 fdtol->fdl_holdcount = 0; 2599 fdtol->fdl_wakeup = 0; 2600 fdtol->fdl_leader = leader; 2601 if (old != NULL) { 2602 fdtol->fdl_next = old->fdl_next; 2603 fdtol->fdl_prev = old; 2604 old->fdl_next = fdtol; 2605 fdtol->fdl_next->fdl_prev = fdtol; 2606 } else { 2607 fdtol->fdl_next = fdtol; 2608 fdtol->fdl_prev = fdtol; 2609 } 2610 return fdtol; 2611 } 2612 2613 /* 2614 * Scan all file pointers in the system. The callback is made with 2615 * the master list spinlock held exclusively. 2616 * 2617 * MPSAFE 2618 */ 2619 void 2620 allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) 2621 { 2622 struct file *fp; 2623 int res; 2624 2625 spin_lock(&filehead_spin); 2626 LIST_FOREACH(fp, &filehead, f_list) { 2627 res = callback(fp, data); 2628 if (res < 0) 2629 break; 2630 } 2631 spin_unlock(&filehead_spin); 2632 } 2633 2634 /* 2635 * Get file structures. 2636 * 2637 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) 2638 */ 2639 2640 struct sysctl_kern_file_info { 2641 int count; 2642 int error; 2643 struct sysctl_req *req; 2644 }; 2645 2646 static int sysctl_kern_file_callback(struct proc *p, void *data); 2647 2648 static int 2649 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2650 { 2651 struct sysctl_kern_file_info info; 2652 2653 /* 2654 * Note: because the number of file descriptors is calculated 2655 * in different ways for sizing vs returning the data, 2656 * there is information leakage from the first loop. However, 2657 * it is of a similar order of magnitude to the leakage from 2658 * global system statistics such as kern.openfiles. 2659 * 2660 * When just doing a count, note that we cannot just count 2661 * the elements and add f_count via the filehead list because 2662 * threaded processes share their descriptor table and f_count might 2663 * still be '1' in that case. 2664 * 2665 * Since the SYSCTL op can block, we must hold the process to 2666 * prevent it being ripped out from under us either in the 2667 * file descriptor loop or in the greater LIST_FOREACH. The 2668 * process may be in varying states of disrepair. If the process 2669 * is in SZOMB we may have caught it just as it is being removed 2670 * from the allproc list, we must skip it in that case to maintain 2671 * an unbroken chain through the allproc list. 2672 */ 2673 info.count = 0; 2674 info.error = 0; 2675 info.req = req; 2676 allproc_scan(sysctl_kern_file_callback, &info); 2677 2678 /* 2679 * When just calculating the size, overestimate a bit to try to 2680 * prevent system activity from causing the buffer-fill call 2681 * to fail later on. 2682 */ 2683 if (req->oldptr == NULL) { 2684 info.count = (info.count + 16) + (info.count / 10); 2685 info.error = SYSCTL_OUT(req, NULL, 2686 info.count * sizeof(struct kinfo_file)); 2687 } 2688 return (info.error); 2689 } 2690 2691 static int 2692 sysctl_kern_file_callback(struct proc *p, void *data) 2693 { 2694 struct sysctl_kern_file_info *info = data; 2695 struct kinfo_file kf; 2696 struct filedesc *fdp; 2697 struct file *fp; 2698 uid_t uid; 2699 int n; 2700 2701 if (p->p_stat == SIDL || p->p_stat == SZOMB) 2702 return(0); 2703 if (!PRISON_CHECK(info->req->td->td_ucred, p->p_ucred) != 0) 2704 return(0); 2705 2706 /* 2707 * Softref the fdp to prevent it from being destroyed 2708 */ 2709 spin_lock(&p->p_spin); 2710 if ((fdp = p->p_fd) == NULL) { 2711 spin_unlock(&p->p_spin); 2712 return(0); 2713 } 2714 atomic_add_int(&fdp->fd_softrefs, 1); 2715 spin_unlock(&p->p_spin); 2716 2717 /* 2718 * The fdp's own spinlock prevents the contents from being 2719 * modified. 2720 */ 2721 spin_lock(&fdp->fd_spin); 2722 for (n = 0; n < fdp->fd_nfiles; ++n) { 2723 if ((fp = fdp->fd_files[n].fp) == NULL) 2724 continue; 2725 if (info->req->oldptr == NULL) { 2726 ++info->count; 2727 } else { 2728 uid = p->p_ucred ? p->p_ucred->cr_uid : -1; 2729 kcore_make_file(&kf, fp, p->p_pid, uid, n); 2730 spin_unlock(&fdp->fd_spin); 2731 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); 2732 spin_lock(&fdp->fd_spin); 2733 if (info->error) 2734 break; 2735 } 2736 } 2737 spin_unlock(&fdp->fd_spin); 2738 atomic_subtract_int(&fdp->fd_softrefs, 1); 2739 if (info->error) 2740 return(-1); 2741 return(0); 2742 } 2743 2744 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2745 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 2746 2747 SYSCTL_INT(_kern, OID_AUTO, minfilesperproc, CTLFLAG_RW, 2748 &minfilesperproc, 0, "Minimum files allowed open per process"); 2749 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2750 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2751 SYSCTL_INT(_kern, OID_AUTO, maxfilesperuser, CTLFLAG_RW, 2752 &maxfilesperuser, 0, "Maximum files allowed open per user"); 2753 2754 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2755 &maxfiles, 0, "Maximum number of files"); 2756 2757 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 2758 &maxfilesrootres, 0, "Descriptors reserved for root use"); 2759 2760 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2761 &nfiles, 0, "System-wide number of open files"); 2762 2763 static void 2764 fildesc_drvinit(void *unused) 2765 { 2766 int fd; 2767 2768 for (fd = 0; fd < NUMFDESC; fd++) { 2769 make_dev(&fildesc_ops, fd, 2770 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 2771 } 2772 2773 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 2774 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 2775 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 2776 } 2777 2778 /* 2779 * MPSAFE 2780 */ 2781 struct fileops badfileops = { 2782 .fo_read = badfo_readwrite, 2783 .fo_write = badfo_readwrite, 2784 .fo_ioctl = badfo_ioctl, 2785 .fo_kqfilter = badfo_kqfilter, 2786 .fo_stat = badfo_stat, 2787 .fo_close = badfo_close, 2788 .fo_shutdown = badfo_shutdown 2789 }; 2790 2791 int 2792 badfo_readwrite( 2793 struct file *fp, 2794 struct uio *uio, 2795 struct ucred *cred, 2796 int flags 2797 ) { 2798 return (EBADF); 2799 } 2800 2801 int 2802 badfo_ioctl(struct file *fp, u_long com, caddr_t data, 2803 struct ucred *cred, struct sysmsg *msgv) 2804 { 2805 return (EBADF); 2806 } 2807 2808 /* 2809 * Must return an error to prevent registration, typically 2810 * due to a revoked descriptor (file_filtops assigned). 2811 */ 2812 int 2813 badfo_kqfilter(struct file *fp, struct knote *kn) 2814 { 2815 return (EOPNOTSUPP); 2816 } 2817 2818 /* 2819 * MPSAFE 2820 */ 2821 int 2822 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) 2823 { 2824 return (EBADF); 2825 } 2826 2827 /* 2828 * MPSAFE 2829 */ 2830 int 2831 badfo_close(struct file *fp) 2832 { 2833 return (EBADF); 2834 } 2835 2836 /* 2837 * MPSAFE 2838 */ 2839 int 2840 badfo_shutdown(struct file *fp, int how) 2841 { 2842 return (EBADF); 2843 } 2844 2845 /* 2846 * MPSAFE 2847 */ 2848 int 2849 nofo_shutdown(struct file *fp, int how) 2850 { 2851 return (EOPNOTSUPP); 2852 } 2853 2854 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2855 fildesc_drvinit,NULL) 2856