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/stat.h> 90 #include <sys/filio.h> 91 #include <sys/fcntl.h> 92 #include <sys/unistd.h> 93 #include <sys/resourcevar.h> 94 #include <sys/event.h> 95 #include <sys/kern_syscall.h> 96 #include <sys/kcore.h> 97 #include <sys/kinfo.h> 98 #include <sys/un.h> 99 100 #include <vm/vm.h> 101 #include <vm/vm_extern.h> 102 103 #include <sys/thread2.h> 104 #include <sys/file2.h> 105 #include <sys/spinlock2.h> 106 107 static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd); 108 static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr); 109 static struct file *funsetfd_locked (struct filedesc *fdp, int fd); 110 static void ffree(struct file *fp); 111 112 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 113 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 114 "file desc to leader structures"); 115 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 116 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 117 118 static struct krate krate_uidinfo = { .freq = 1 }; 119 120 static d_open_t fdopen; 121 #define NUMFDESC 64 122 123 #define CDEV_MAJOR 22 124 static struct dev_ops fildesc_ops = { 125 { "FD", 0, 0 }, 126 .d_open = fdopen, 127 }; 128 129 /* 130 * Descriptor management. 131 */ 132 static struct filelist filehead = LIST_HEAD_INITIALIZER(&filehead); 133 static struct spinlock filehead_spin = SPINLOCK_INITIALIZER(&filehead_spin); 134 static int nfiles; /* actual number of open files */ 135 extern int cmask; 136 137 /* 138 * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared. 139 * 140 * MPSAFE - must be called with fdp->fd_spin exclusively held 141 */ 142 static __inline 143 void 144 fdfixup_locked(struct filedesc *fdp, int fd) 145 { 146 if (fd < fdp->fd_freefile) { 147 fdp->fd_freefile = fd; 148 } 149 while (fdp->fd_lastfile >= 0 && 150 fdp->fd_files[fdp->fd_lastfile].fp == NULL && 151 fdp->fd_files[fdp->fd_lastfile].reserved == 0 152 ) { 153 --fdp->fd_lastfile; 154 } 155 } 156 157 /* 158 * System calls on descriptors. 159 * 160 * MPSAFE 161 */ 162 int 163 sys_getdtablesize(struct getdtablesize_args *uap) 164 { 165 struct proc *p = curproc; 166 struct plimit *limit = p->p_limit; 167 int dtsize; 168 169 spin_lock(&limit->p_spin); 170 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 171 dtsize = INT_MAX; 172 else 173 dtsize = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 174 spin_unlock(&limit->p_spin); 175 176 if (dtsize > maxfilesperproc) 177 dtsize = maxfilesperproc; 178 if (dtsize < minfilesperproc) 179 dtsize = minfilesperproc; 180 if (p->p_ucred->cr_uid && dtsize > maxfilesperuser) 181 dtsize = maxfilesperuser; 182 uap->sysmsg_result = dtsize; 183 return (0); 184 } 185 186 /* 187 * Duplicate a file descriptor to a particular value. 188 * 189 * note: keep in mind that a potential race condition exists when closing 190 * descriptors from a shared descriptor table (via rfork). 191 * 192 * MPSAFE 193 */ 194 int 195 sys_dup2(struct dup2_args *uap) 196 { 197 int error; 198 int fd = 0; 199 200 error = kern_dup(DUP_FIXED, uap->from, uap->to, &fd); 201 uap->sysmsg_fds[0] = fd; 202 203 return (error); 204 } 205 206 /* 207 * Duplicate a file descriptor. 208 * 209 * MPSAFE 210 */ 211 int 212 sys_dup(struct dup_args *uap) 213 { 214 int error; 215 int fd = 0; 216 217 error = kern_dup(DUP_VARIABLE, uap->fd, 0, &fd); 218 uap->sysmsg_fds[0] = fd; 219 220 return (error); 221 } 222 223 /* 224 * MPALMOSTSAFE - acquires mplock for fp operations 225 */ 226 int 227 kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred) 228 { 229 struct thread *td = curthread; 230 struct proc *p = td->td_proc; 231 struct file *fp; 232 struct vnode *vp; 233 u_int newmin; 234 u_int oflags; 235 u_int nflags; 236 int tmp, error, flg = F_POSIX; 237 238 KKASSERT(p); 239 240 /* 241 * Operations on file descriptors that do not require a file pointer. 242 */ 243 switch (cmd) { 244 case F_GETFD: 245 error = fgetfdflags(p->p_fd, fd, &tmp); 246 if (error == 0) 247 dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0; 248 return (error); 249 250 case F_SETFD: 251 if (dat->fc_cloexec & FD_CLOEXEC) 252 error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE); 253 else 254 error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE); 255 return (error); 256 case F_DUPFD: 257 newmin = dat->fc_fd; 258 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); 259 return (error); 260 default: 261 break; 262 } 263 264 /* 265 * Operations on file pointers 266 */ 267 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 268 return (EBADF); 269 270 switch (cmd) { 271 case F_GETFL: 272 dat->fc_flags = OFLAGS(fp->f_flag); 273 error = 0; 274 break; 275 276 case F_SETFL: 277 oflags = fp->f_flag; 278 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 279 nflags |= oflags & ~FCNTLFLAGS; 280 281 error = 0; 282 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) 283 error = EINVAL; 284 if (error == 0 && ((nflags ^ oflags) & FASYNC)) { 285 tmp = nflags & FASYNC; 286 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, 287 cred, NULL); 288 } 289 if (error == 0) 290 fp->f_flag = nflags; 291 break; 292 293 case F_GETOWN: 294 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, 295 cred, NULL); 296 break; 297 298 case F_SETOWN: 299 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, 300 cred, NULL); 301 break; 302 303 case F_SETLKW: 304 flg |= F_WAIT; 305 /* Fall into F_SETLK */ 306 307 case F_SETLK: 308 if (fp->f_type != DTYPE_VNODE) { 309 error = EBADF; 310 break; 311 } 312 vp = (struct vnode *)fp->f_data; 313 314 /* 315 * copyin/lockop may block 316 */ 317 if (dat->fc_flock.l_whence == SEEK_CUR) 318 dat->fc_flock.l_start += fp->f_offset; 319 320 switch (dat->fc_flock.l_type) { 321 case F_RDLCK: 322 if ((fp->f_flag & FREAD) == 0) { 323 error = EBADF; 324 break; 325 } 326 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 327 lwkt_gettoken(&p->p_leader->p_token); 328 p->p_leader->p_flags |= P_ADVLOCK; 329 lwkt_reltoken(&p->p_leader->p_token); 330 } 331 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 332 &dat->fc_flock, flg); 333 break; 334 case F_WRLCK: 335 if ((fp->f_flag & FWRITE) == 0) { 336 error = EBADF; 337 break; 338 } 339 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 340 lwkt_gettoken(&p->p_leader->p_token); 341 p->p_leader->p_flags |= P_ADVLOCK; 342 lwkt_reltoken(&p->p_leader->p_token); 343 } 344 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 345 &dat->fc_flock, flg); 346 break; 347 case F_UNLCK: 348 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 349 &dat->fc_flock, F_POSIX); 350 break; 351 default: 352 error = EINVAL; 353 break; 354 } 355 356 /* 357 * It is possible to race a close() on the descriptor while 358 * we were blocked getting the lock. If this occurs the 359 * close might not have caught the lock. 360 */ 361 if (checkfdclosed(p->p_fd, fd, fp)) { 362 dat->fc_flock.l_whence = SEEK_SET; 363 dat->fc_flock.l_start = 0; 364 dat->fc_flock.l_len = 0; 365 dat->fc_flock.l_type = F_UNLCK; 366 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 367 F_UNLCK, &dat->fc_flock, F_POSIX); 368 } 369 break; 370 371 case F_GETLK: 372 if (fp->f_type != DTYPE_VNODE) { 373 error = EBADF; 374 break; 375 } 376 vp = (struct vnode *)fp->f_data; 377 /* 378 * copyin/lockop may block 379 */ 380 if (dat->fc_flock.l_type != F_RDLCK && 381 dat->fc_flock.l_type != F_WRLCK && 382 dat->fc_flock.l_type != F_UNLCK) { 383 error = EINVAL; 384 break; 385 } 386 if (dat->fc_flock.l_whence == SEEK_CUR) 387 dat->fc_flock.l_start += fp->f_offset; 388 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 389 &dat->fc_flock, F_POSIX); 390 break; 391 default: 392 error = EINVAL; 393 break; 394 } 395 396 fdrop(fp); 397 return (error); 398 } 399 400 /* 401 * The file control system call. 402 * 403 * MPSAFE 404 */ 405 int 406 sys_fcntl(struct fcntl_args *uap) 407 { 408 union fcntl_dat dat; 409 int error; 410 411 switch (uap->cmd) { 412 case F_DUPFD: 413 dat.fc_fd = uap->arg; 414 break; 415 case F_SETFD: 416 dat.fc_cloexec = uap->arg; 417 break; 418 case F_SETFL: 419 dat.fc_flags = uap->arg; 420 break; 421 case F_SETOWN: 422 dat.fc_owner = uap->arg; 423 break; 424 case F_SETLKW: 425 case F_SETLK: 426 case F_GETLK: 427 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 428 sizeof(struct flock)); 429 if (error) 430 return (error); 431 break; 432 } 433 434 error = kern_fcntl(uap->fd, uap->cmd, &dat, curthread->td_ucred); 435 436 if (error == 0) { 437 switch (uap->cmd) { 438 case F_DUPFD: 439 uap->sysmsg_result = dat.fc_fd; 440 break; 441 case F_GETFD: 442 uap->sysmsg_result = dat.fc_cloexec; 443 break; 444 case F_GETFL: 445 uap->sysmsg_result = dat.fc_flags; 446 break; 447 case F_GETOWN: 448 uap->sysmsg_result = dat.fc_owner; 449 case F_GETLK: 450 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 451 sizeof(struct flock)); 452 break; 453 } 454 } 455 456 return (error); 457 } 458 459 /* 460 * Common code for dup, dup2, and fcntl(F_DUPFD). 461 * 462 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells 463 * kern_dup() to destructively dup over an existing file descriptor if new 464 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest 465 * unused file descriptor that is greater than or equal to new. 466 * 467 * MPSAFE 468 */ 469 int 470 kern_dup(enum dup_type type, int old, int new, int *res) 471 { 472 struct thread *td = curthread; 473 struct proc *p = td->td_proc; 474 struct filedesc *fdp = p->p_fd; 475 struct file *fp; 476 struct file *delfp; 477 int oldflags; 478 int holdleaders; 479 int dtsize; 480 int error, newfd; 481 482 /* 483 * Verify that we have a valid descriptor to dup from and 484 * possibly to dup to. 485 * 486 * NOTE: maxfilesperuser is not applicable to dup() 487 */ 488 retry: 489 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 490 dtsize = INT_MAX; 491 else 492 dtsize = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 493 if (dtsize > maxfilesperproc) 494 dtsize = maxfilesperproc; 495 if (dtsize < minfilesperproc) 496 dtsize = minfilesperproc; 497 498 if (new < 0 || new > dtsize) 499 return (EINVAL); 500 501 spin_lock(&fdp->fd_spin); 502 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { 503 spin_unlock(&fdp->fd_spin); 504 return (EBADF); 505 } 506 if (type == DUP_FIXED && old == new) { 507 *res = new; 508 spin_unlock(&fdp->fd_spin); 509 return (0); 510 } 511 fp = fdp->fd_files[old].fp; 512 oldflags = fdp->fd_files[old].fileflags; 513 fhold(fp); /* MPSAFE - can be called with a spinlock held */ 514 515 /* 516 * Allocate a new descriptor if DUP_VARIABLE, or expand the table 517 * if the requested descriptor is beyond the current table size. 518 * 519 * This can block. Retry if the source descriptor no longer matches 520 * or if our expectation in the expansion case races. 521 * 522 * If we are not expanding or allocating a new decriptor, then reset 523 * the target descriptor to a reserved state so we have a uniform 524 * setup for the next code block. 525 */ 526 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) { 527 spin_unlock(&fdp->fd_spin); 528 error = fdalloc(p, new, &newfd); 529 spin_lock(&fdp->fd_spin); 530 if (error) { 531 spin_unlock(&fdp->fd_spin); 532 fdrop(fp); 533 return (error); 534 } 535 /* 536 * Check for ripout 537 */ 538 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { 539 fsetfd_locked(fdp, NULL, newfd); 540 spin_unlock(&fdp->fd_spin); 541 fdrop(fp); 542 goto retry; 543 } 544 /* 545 * Check for expansion race 546 */ 547 if (type != DUP_VARIABLE && new != newfd) { 548 fsetfd_locked(fdp, NULL, newfd); 549 spin_unlock(&fdp->fd_spin); 550 fdrop(fp); 551 goto retry; 552 } 553 /* 554 * Check for ripout, newfd reused old (this case probably 555 * can't occur). 556 */ 557 if (old == newfd) { 558 fsetfd_locked(fdp, NULL, newfd); 559 spin_unlock(&fdp->fd_spin); 560 fdrop(fp); 561 goto retry; 562 } 563 new = newfd; 564 delfp = NULL; 565 } else { 566 if (fdp->fd_files[new].reserved) { 567 spin_unlock(&fdp->fd_spin); 568 fdrop(fp); 569 kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new); 570 tsleep(fdp, 0, "fdres", hz); 571 goto retry; 572 } 573 574 /* 575 * If the target descriptor was never allocated we have 576 * to allocate it. If it was we have to clean out the 577 * old descriptor. delfp inherits the ref from the 578 * descriptor table. 579 */ 580 delfp = fdp->fd_files[new].fp; 581 fdp->fd_files[new].fp = NULL; 582 fdp->fd_files[new].reserved = 1; 583 if (delfp == NULL) { 584 fdreserve_locked(fdp, new, 1); 585 if (new > fdp->fd_lastfile) 586 fdp->fd_lastfile = new; 587 } 588 589 } 590 591 /* 592 * NOTE: still holding an exclusive spinlock 593 */ 594 595 /* 596 * If a descriptor is being overwritten we may hve to tell 597 * fdfree() to sleep to ensure that all relevant process 598 * leaders can be traversed in closef(). 599 */ 600 if (delfp != NULL && p->p_fdtol != NULL) { 601 fdp->fd_holdleaderscount++; 602 holdleaders = 1; 603 } else { 604 holdleaders = 0; 605 } 606 KASSERT(delfp == NULL || type == DUP_FIXED, 607 ("dup() picked an open file")); 608 609 /* 610 * Duplicate the source descriptor, update lastfile. If the new 611 * descriptor was not allocated and we aren't replacing an existing 612 * descriptor we have to mark the descriptor as being in use. 613 * 614 * The fd_files[] array inherits fp's hold reference. 615 */ 616 fsetfd_locked(fdp, fp, new); 617 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; 618 spin_unlock(&fdp->fd_spin); 619 fdrop(fp); 620 *res = new; 621 622 /* 623 * If we dup'd over a valid file, we now own the reference to it 624 * and must dispose of it using closef() semantics (as if a 625 * close() were performed on it). 626 */ 627 if (delfp) { 628 if (SLIST_FIRST(&delfp->f_klist)) 629 knote_fdclose(delfp, fdp, new); 630 closef(delfp, p); 631 if (holdleaders) { 632 spin_lock(&fdp->fd_spin); 633 fdp->fd_holdleaderscount--; 634 if (fdp->fd_holdleaderscount == 0 && 635 fdp->fd_holdleaderswakeup != 0) { 636 fdp->fd_holdleaderswakeup = 0; 637 spin_unlock(&fdp->fd_spin); 638 wakeup(&fdp->fd_holdleaderscount); 639 } else { 640 spin_unlock(&fdp->fd_spin); 641 } 642 } 643 } 644 return (0); 645 } 646 647 /* 648 * If sigio is on the list associated with a process or process group, 649 * disable signalling from the device, remove sigio from the list and 650 * free sigio. 651 * 652 * MPSAFE 653 */ 654 void 655 funsetown(struct sigio **sigiop) 656 { 657 struct pgrp *pgrp; 658 struct proc *p; 659 struct sigio *sigio; 660 661 if ((sigio = *sigiop) != NULL) { 662 lwkt_gettoken(&proc_token); /* protect sigio */ 663 KKASSERT(sigiop == sigio->sio_myref); 664 sigio = *sigiop; 665 *sigiop = NULL; 666 lwkt_reltoken(&proc_token); 667 } 668 if (sigio == NULL) 669 return; 670 671 if (sigio->sio_pgid < 0) { 672 pgrp = sigio->sio_pgrp; 673 sigio->sio_pgrp = NULL; 674 lwkt_gettoken(&pgrp->pg_token); 675 SLIST_REMOVE(&pgrp->pg_sigiolst, sigio, sigio, sio_pgsigio); 676 lwkt_reltoken(&pgrp->pg_token); 677 pgrel(pgrp); 678 } else /* if ((*sigiop)->sio_pgid > 0) */ { 679 p = sigio->sio_proc; 680 sigio->sio_proc = NULL; 681 PHOLD(p); 682 lwkt_gettoken(&p->p_token); 683 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, sio_pgsigio); 684 lwkt_reltoken(&p->p_token); 685 PRELE(p); 686 } 687 crfree(sigio->sio_ucred); 688 sigio->sio_ucred = NULL; 689 kfree(sigio, M_SIGIO); 690 } 691 692 /* 693 * Free a list of sigio structures. Caller is responsible for ensuring 694 * that the list is MPSAFE. 695 * 696 * MPSAFE 697 */ 698 void 699 funsetownlst(struct sigiolst *sigiolst) 700 { 701 struct sigio *sigio; 702 703 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 704 funsetown(sigio->sio_myref); 705 } 706 707 /* 708 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 709 * 710 * After permission checking, add a sigio structure to the sigio list for 711 * the process or process group. 712 * 713 * MPSAFE 714 */ 715 int 716 fsetown(pid_t pgid, struct sigio **sigiop) 717 { 718 struct proc *proc = NULL; 719 struct pgrp *pgrp = NULL; 720 struct sigio *sigio; 721 int error; 722 723 if (pgid == 0) { 724 funsetown(sigiop); 725 return (0); 726 } 727 728 if (pgid > 0) { 729 proc = pfind(pgid); 730 if (proc == NULL) { 731 error = ESRCH; 732 goto done; 733 } 734 735 /* 736 * Policy - Don't allow a process to FSETOWN a process 737 * in another session. 738 * 739 * Remove this test to allow maximum flexibility or 740 * restrict FSETOWN to the current process or process 741 * group for maximum safety. 742 */ 743 if (proc->p_session != curproc->p_session) { 744 error = EPERM; 745 goto done; 746 } 747 } else /* if (pgid < 0) */ { 748 pgrp = pgfind(-pgid); 749 if (pgrp == NULL) { 750 error = ESRCH; 751 goto done; 752 } 753 754 /* 755 * Policy - Don't allow a process to FSETOWN a process 756 * in another session. 757 * 758 * Remove this test to allow maximum flexibility or 759 * restrict FSETOWN to the current process or process 760 * group for maximum safety. 761 */ 762 if (pgrp->pg_session != curproc->p_session) { 763 error = EPERM; 764 goto done; 765 } 766 } 767 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK | M_ZERO); 768 if (pgid > 0) { 769 KKASSERT(pgrp == NULL); 770 lwkt_gettoken(&proc->p_token); 771 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 772 sigio->sio_proc = proc; 773 lwkt_reltoken(&proc->p_token); 774 } else { 775 KKASSERT(proc == NULL); 776 lwkt_gettoken(&pgrp->pg_token); 777 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 778 sigio->sio_pgrp = pgrp; 779 lwkt_reltoken(&pgrp->pg_token); 780 pgrp = NULL; 781 } 782 sigio->sio_pgid = pgid; 783 sigio->sio_ucred = crhold(curthread->td_ucred); 784 /* It would be convenient if p_ruid was in ucred. */ 785 sigio->sio_ruid = sigio->sio_ucred->cr_ruid; 786 sigio->sio_myref = sigiop; 787 788 lwkt_gettoken(&proc_token); 789 while (*sigiop) 790 funsetown(sigiop); 791 *sigiop = sigio; 792 lwkt_reltoken(&proc_token); 793 error = 0; 794 done: 795 if (pgrp) 796 pgrel(pgrp); 797 if (proc) 798 PRELE(proc); 799 return (error); 800 } 801 802 /* 803 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 804 * 805 * MPSAFE 806 */ 807 pid_t 808 fgetown(struct sigio **sigiop) 809 { 810 struct sigio *sigio; 811 pid_t own; 812 813 lwkt_gettoken(&proc_token); 814 sigio = *sigiop; 815 own = (sigio != NULL ? sigio->sio_pgid : 0); 816 lwkt_reltoken(&proc_token); 817 818 return (own); 819 } 820 821 /* 822 * Close many file descriptors. 823 * 824 * MPSAFE 825 */ 826 int 827 sys_closefrom(struct closefrom_args *uap) 828 { 829 return(kern_closefrom(uap->fd)); 830 } 831 832 /* 833 * Close all file descriptors greater then or equal to fd 834 * 835 * MPSAFE 836 */ 837 int 838 kern_closefrom(int fd) 839 { 840 struct thread *td = curthread; 841 struct proc *p = td->td_proc; 842 struct filedesc *fdp; 843 844 KKASSERT(p); 845 fdp = p->p_fd; 846 847 if (fd < 0) 848 return (EINVAL); 849 850 /* 851 * NOTE: This function will skip unassociated descriptors and 852 * reserved descriptors that have not yet been assigned. 853 * fd_lastfile can change as a side effect of kern_close(). 854 */ 855 spin_lock(&fdp->fd_spin); 856 while (fd <= fdp->fd_lastfile) { 857 if (fdp->fd_files[fd].fp != NULL) { 858 spin_unlock(&fdp->fd_spin); 859 /* ok if this races another close */ 860 if (kern_close(fd) == EINTR) 861 return (EINTR); 862 spin_lock(&fdp->fd_spin); 863 } 864 ++fd; 865 } 866 spin_unlock(&fdp->fd_spin); 867 return (0); 868 } 869 870 /* 871 * Close a file descriptor. 872 * 873 * MPSAFE 874 */ 875 int 876 sys_close(struct close_args *uap) 877 { 878 return(kern_close(uap->fd)); 879 } 880 881 /* 882 * MPSAFE 883 */ 884 int 885 kern_close(int fd) 886 { 887 struct thread *td = curthread; 888 struct proc *p = td->td_proc; 889 struct filedesc *fdp; 890 struct file *fp; 891 int error; 892 int holdleaders; 893 894 KKASSERT(p); 895 fdp = p->p_fd; 896 897 spin_lock(&fdp->fd_spin); 898 if ((fp = funsetfd_locked(fdp, fd)) == NULL) { 899 spin_unlock(&fdp->fd_spin); 900 return (EBADF); 901 } 902 holdleaders = 0; 903 if (p->p_fdtol != NULL) { 904 /* 905 * Ask fdfree() to sleep to ensure that all relevant 906 * process leaders can be traversed in closef(). 907 */ 908 fdp->fd_holdleaderscount++; 909 holdleaders = 1; 910 } 911 912 /* 913 * we now hold the fp reference that used to be owned by the descriptor 914 * array. 915 */ 916 spin_unlock(&fdp->fd_spin); 917 if (SLIST_FIRST(&fp->f_klist)) 918 knote_fdclose(fp, fdp, fd); 919 error = closef(fp, p); 920 if (holdleaders) { 921 spin_lock(&fdp->fd_spin); 922 fdp->fd_holdleaderscount--; 923 if (fdp->fd_holdleaderscount == 0 && 924 fdp->fd_holdleaderswakeup != 0) { 925 fdp->fd_holdleaderswakeup = 0; 926 spin_unlock(&fdp->fd_spin); 927 wakeup(&fdp->fd_holdleaderscount); 928 } else { 929 spin_unlock(&fdp->fd_spin); 930 } 931 } 932 return (error); 933 } 934 935 /* 936 * shutdown_args(int fd, int how) 937 */ 938 int 939 kern_shutdown(int fd, int how) 940 { 941 struct thread *td = curthread; 942 struct proc *p = td->td_proc; 943 struct file *fp; 944 int error; 945 946 KKASSERT(p); 947 948 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 949 return (EBADF); 950 error = fo_shutdown(fp, how); 951 fdrop(fp); 952 953 return (error); 954 } 955 956 /* 957 * MPALMOSTSAFE 958 */ 959 int 960 sys_shutdown(struct shutdown_args *uap) 961 { 962 int error; 963 964 error = kern_shutdown(uap->s, uap->how); 965 966 return (error); 967 } 968 969 /* 970 * MPSAFE 971 */ 972 int 973 kern_fstat(int fd, struct stat *ub) 974 { 975 struct thread *td = curthread; 976 struct proc *p = td->td_proc; 977 struct file *fp; 978 int error; 979 980 KKASSERT(p); 981 982 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 983 return (EBADF); 984 error = fo_stat(fp, ub, td->td_ucred); 985 fdrop(fp); 986 987 return (error); 988 } 989 990 /* 991 * Return status information about a file descriptor. 992 * 993 * MPSAFE 994 */ 995 int 996 sys_fstat(struct fstat_args *uap) 997 { 998 struct stat st; 999 int error; 1000 1001 error = kern_fstat(uap->fd, &st); 1002 1003 if (error == 0) 1004 error = copyout(&st, uap->sb, sizeof(st)); 1005 return (error); 1006 } 1007 1008 /* 1009 * Return pathconf information about a file descriptor. 1010 * 1011 * MPALMOSTSAFE 1012 */ 1013 int 1014 sys_fpathconf(struct fpathconf_args *uap) 1015 { 1016 struct thread *td = curthread; 1017 struct proc *p = td->td_proc; 1018 struct file *fp; 1019 struct vnode *vp; 1020 int error = 0; 1021 1022 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 1023 return (EBADF); 1024 1025 switch (fp->f_type) { 1026 case DTYPE_PIPE: 1027 case DTYPE_SOCKET: 1028 if (uap->name != _PC_PIPE_BUF) { 1029 error = EINVAL; 1030 } else { 1031 uap->sysmsg_result = PIPE_BUF; 1032 error = 0; 1033 } 1034 break; 1035 case DTYPE_FIFO: 1036 case DTYPE_VNODE: 1037 vp = (struct vnode *)fp->f_data; 1038 error = VOP_PATHCONF(vp, uap->name, &uap->sysmsg_reg); 1039 break; 1040 default: 1041 error = EOPNOTSUPP; 1042 break; 1043 } 1044 fdrop(fp); 1045 return(error); 1046 } 1047 1048 static int fdexpand; 1049 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, 1050 "Number of times a file table has been expanded"); 1051 1052 /* 1053 * Grow the file table so it can hold through descriptor (want). 1054 * 1055 * The fdp's spinlock must be held exclusively on entry and may be held 1056 * exclusively on return. The spinlock may be cycled by the routine. 1057 * 1058 * MPSAFE 1059 */ 1060 static void 1061 fdgrow_locked(struct filedesc *fdp, int want) 1062 { 1063 struct fdnode *newfiles; 1064 struct fdnode *oldfiles; 1065 int nf, extra; 1066 1067 nf = fdp->fd_nfiles; 1068 do { 1069 /* nf has to be of the form 2^n - 1 */ 1070 nf = 2 * nf + 1; 1071 } while (nf <= want); 1072 1073 spin_unlock(&fdp->fd_spin); 1074 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); 1075 spin_lock(&fdp->fd_spin); 1076 1077 /* 1078 * We could have raced another extend while we were not holding 1079 * the spinlock. 1080 */ 1081 if (fdp->fd_nfiles >= nf) { 1082 spin_unlock(&fdp->fd_spin); 1083 kfree(newfiles, M_FILEDESC); 1084 spin_lock(&fdp->fd_spin); 1085 return; 1086 } 1087 /* 1088 * Copy the existing ofile and ofileflags arrays 1089 * and zero the new portion of each array. 1090 */ 1091 extra = nf - fdp->fd_nfiles; 1092 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); 1093 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); 1094 1095 oldfiles = fdp->fd_files; 1096 fdp->fd_files = newfiles; 1097 fdp->fd_nfiles = nf; 1098 1099 if (oldfiles != fdp->fd_builtin_files) { 1100 spin_unlock(&fdp->fd_spin); 1101 kfree(oldfiles, M_FILEDESC); 1102 spin_lock(&fdp->fd_spin); 1103 } 1104 fdexpand++; 1105 } 1106 1107 /* 1108 * Number of nodes in right subtree, including the root. 1109 */ 1110 static __inline int 1111 right_subtree_size(int n) 1112 { 1113 return (n ^ (n | (n + 1))); 1114 } 1115 1116 /* 1117 * Bigger ancestor. 1118 */ 1119 static __inline int 1120 right_ancestor(int n) 1121 { 1122 return (n | (n + 1)); 1123 } 1124 1125 /* 1126 * Smaller ancestor. 1127 */ 1128 static __inline int 1129 left_ancestor(int n) 1130 { 1131 return ((n & (n + 1)) - 1); 1132 } 1133 1134 /* 1135 * Traverse the in-place binary tree buttom-up adjusting the allocation 1136 * count so scans can determine where free descriptors are located. 1137 * 1138 * MPSAFE - caller must be holding an exclusive spinlock on fdp 1139 */ 1140 static 1141 void 1142 fdreserve_locked(struct filedesc *fdp, int fd, int incr) 1143 { 1144 while (fd >= 0) { 1145 fdp->fd_files[fd].allocated += incr; 1146 KKASSERT(fdp->fd_files[fd].allocated >= 0); 1147 fd = left_ancestor(fd); 1148 } 1149 } 1150 1151 /* 1152 * Reserve a file descriptor for the process. If no error occurs, the 1153 * caller MUST at some point call fsetfd() or assign a file pointer 1154 * or dispose of the reservation. 1155 * 1156 * MPSAFE 1157 */ 1158 int 1159 fdalloc(struct proc *p, int want, int *result) 1160 { 1161 struct filedesc *fdp = p->p_fd; 1162 struct uidinfo *uip; 1163 int fd, rsize, rsum, node, lim; 1164 1165 /* 1166 * Check dtable size limit 1167 */ 1168 spin_lock(&p->p_limit->p_spin); 1169 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1170 lim = INT_MAX; 1171 else 1172 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1173 spin_unlock(&p->p_limit->p_spin); 1174 1175 if (lim > maxfilesperproc) 1176 lim = maxfilesperproc; 1177 if (lim < minfilesperproc) 1178 lim = minfilesperproc; 1179 if (want >= lim) 1180 return (EMFILE); 1181 1182 /* 1183 * Check that the user has not run out of descriptors (non-root only). 1184 * As a safety measure the dtable is allowed to have at least 1185 * minfilesperproc open fds regardless of the maxfilesperuser limit. 1186 */ 1187 if (p->p_ucred->cr_uid && fdp->fd_nfiles >= minfilesperproc) { 1188 uip = p->p_ucred->cr_uidinfo; 1189 if (uip->ui_openfiles > maxfilesperuser) { 1190 krateprintf(&krate_uidinfo, 1191 "Warning: user %d pid %d (%s) ran out of " 1192 "file descriptors (%d/%d)\n", 1193 p->p_ucred->cr_uid, (int)p->p_pid, 1194 p->p_comm, 1195 uip->ui_openfiles, maxfilesperuser); 1196 return(ENFILE); 1197 } 1198 } 1199 1200 /* 1201 * Grow the dtable if necessary 1202 */ 1203 spin_lock(&fdp->fd_spin); 1204 if (want >= fdp->fd_nfiles) 1205 fdgrow_locked(fdp, want); 1206 1207 /* 1208 * Search for a free descriptor starting at the higher 1209 * of want or fd_freefile. If that fails, consider 1210 * expanding the ofile array. 1211 * 1212 * NOTE! the 'allocated' field is a cumulative recursive allocation 1213 * count. If we happen to see a value of 0 then we can shortcut 1214 * our search. Otherwise we run through through the tree going 1215 * down branches we know have free descriptor(s) until we hit a 1216 * leaf node. The leaf node will be free but will not necessarily 1217 * have an allocated field of 0. 1218 */ 1219 retry: 1220 /* move up the tree looking for a subtree with a free node */ 1221 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); 1222 fd = right_ancestor(fd)) { 1223 if (fdp->fd_files[fd].allocated == 0) 1224 goto found; 1225 1226 rsize = right_subtree_size(fd); 1227 if (fdp->fd_files[fd].allocated == rsize) 1228 continue; /* right subtree full */ 1229 1230 /* 1231 * Free fd is in the right subtree of the tree rooted at fd. 1232 * Call that subtree R. Look for the smallest (leftmost) 1233 * subtree of R with an unallocated fd: continue moving 1234 * down the left branch until encountering a full left 1235 * subtree, then move to the right. 1236 */ 1237 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 1238 node = fd + rsize; 1239 rsum += fdp->fd_files[node].allocated; 1240 if (fdp->fd_files[fd].allocated == rsum + rsize) { 1241 fd = node; /* move to the right */ 1242 if (fdp->fd_files[node].allocated == 0) 1243 goto found; 1244 rsum = 0; 1245 } 1246 } 1247 goto found; 1248 } 1249 1250 /* 1251 * No space in current array. Expand? 1252 */ 1253 if (fdp->fd_nfiles >= lim) { 1254 spin_unlock(&fdp->fd_spin); 1255 return (EMFILE); 1256 } 1257 fdgrow_locked(fdp, want); 1258 goto retry; 1259 1260 found: 1261 KKASSERT(fd < fdp->fd_nfiles); 1262 if (fd > fdp->fd_lastfile) 1263 fdp->fd_lastfile = fd; 1264 if (want <= fdp->fd_freefile) 1265 fdp->fd_freefile = fd; 1266 *result = fd; 1267 KKASSERT(fdp->fd_files[fd].fp == NULL); 1268 KKASSERT(fdp->fd_files[fd].reserved == 0); 1269 fdp->fd_files[fd].fileflags = 0; 1270 fdp->fd_files[fd].reserved = 1; 1271 fdreserve_locked(fdp, fd, 1); 1272 spin_unlock(&fdp->fd_spin); 1273 return (0); 1274 } 1275 1276 /* 1277 * Check to see whether n user file descriptors 1278 * are available to the process p. 1279 * 1280 * MPSAFE 1281 */ 1282 int 1283 fdavail(struct proc *p, int n) 1284 { 1285 struct filedesc *fdp = p->p_fd; 1286 struct fdnode *fdnode; 1287 int i, lim, last; 1288 1289 spin_lock(&p->p_limit->p_spin); 1290 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1291 lim = INT_MAX; 1292 else 1293 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1294 spin_unlock(&p->p_limit->p_spin); 1295 1296 if (lim > maxfilesperproc) 1297 lim = maxfilesperproc; 1298 if (lim < minfilesperproc) 1299 lim = minfilesperproc; 1300 1301 spin_lock(&fdp->fd_spin); 1302 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { 1303 spin_unlock(&fdp->fd_spin); 1304 return (1); 1305 } 1306 last = min(fdp->fd_nfiles, lim); 1307 fdnode = &fdp->fd_files[fdp->fd_freefile]; 1308 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { 1309 if (fdnode->fp == NULL && --n <= 0) { 1310 spin_unlock(&fdp->fd_spin); 1311 return (1); 1312 } 1313 } 1314 spin_unlock(&fdp->fd_spin); 1315 return (0); 1316 } 1317 1318 /* 1319 * Revoke open descriptors referencing (f_data, f_type) 1320 * 1321 * Any revoke executed within a prison is only able to 1322 * revoke descriptors for processes within that prison. 1323 * 1324 * Returns 0 on success or an error code. 1325 */ 1326 struct fdrevoke_info { 1327 void *data; 1328 short type; 1329 short unused; 1330 int count; 1331 int intransit; 1332 struct ucred *cred; 1333 struct file *nfp; 1334 }; 1335 1336 static int fdrevoke_check_callback(struct file *fp, void *vinfo); 1337 static int fdrevoke_proc_callback(struct proc *p, void *vinfo); 1338 1339 int 1340 fdrevoke(void *f_data, short f_type, struct ucred *cred) 1341 { 1342 struct fdrevoke_info info; 1343 int error; 1344 1345 bzero(&info, sizeof(info)); 1346 info.data = f_data; 1347 info.type = f_type; 1348 info.cred = cred; 1349 error = falloc(NULL, &info.nfp, NULL); 1350 if (error) 1351 return (error); 1352 1353 /* 1354 * Scan the file pointer table once. dups do not dup file pointers, 1355 * only descriptors, so there is no leak. Set FREVOKED on the fps 1356 * being revoked. 1357 */ 1358 allfiles_scan_exclusive(fdrevoke_check_callback, &info); 1359 1360 /* 1361 * If any fps were marked track down the related descriptors 1362 * and close them. Any dup()s at this point will notice 1363 * the FREVOKED already set in the fp and do the right thing. 1364 * 1365 * Any fps with non-zero msgcounts (aka sent over a unix-domain 1366 * socket) bumped the intransit counter and will require a 1367 * scan. Races against fps leaving the socket are closed by 1368 * the socket code checking for FREVOKED. 1369 */ 1370 if (info.count) 1371 allproc_scan(fdrevoke_proc_callback, &info); 1372 if (info.intransit) 1373 unp_revoke_gc(info.nfp); 1374 fdrop(info.nfp); 1375 return(0); 1376 } 1377 1378 /* 1379 * Locate matching file pointers directly. 1380 * 1381 * WARNING: allfiles_scan_exclusive() holds a spinlock through these calls! 1382 */ 1383 static int 1384 fdrevoke_check_callback(struct file *fp, void *vinfo) 1385 { 1386 struct fdrevoke_info *info = vinfo; 1387 1388 /* 1389 * File pointers already flagged for revokation are skipped. 1390 */ 1391 if (fp->f_flag & FREVOKED) 1392 return(0); 1393 1394 /* 1395 * If revoking from a prison file pointers created outside of 1396 * that prison, or file pointers without creds, cannot be revoked. 1397 */ 1398 if (info->cred->cr_prison && 1399 (fp->f_cred == NULL || 1400 info->cred->cr_prison != fp->f_cred->cr_prison)) { 1401 return(0); 1402 } 1403 1404 /* 1405 * If the file pointer matches then mark it for revocation. The 1406 * flag is currently only used by unp_revoke_gc(). 1407 * 1408 * info->count is a heuristic and can race in a SMP environment. 1409 */ 1410 if (info->data == fp->f_data && info->type == fp->f_type) { 1411 atomic_set_int(&fp->f_flag, FREVOKED); 1412 info->count += fp->f_count; 1413 if (fp->f_msgcount) 1414 ++info->intransit; 1415 } 1416 return(0); 1417 } 1418 1419 /* 1420 * Locate matching file pointers via process descriptor tables. 1421 */ 1422 static int 1423 fdrevoke_proc_callback(struct proc *p, void *vinfo) 1424 { 1425 struct fdrevoke_info *info = vinfo; 1426 struct filedesc *fdp; 1427 struct file *fp; 1428 int n; 1429 1430 if (p->p_stat == SIDL || p->p_stat == SZOMB) 1431 return(0); 1432 if (info->cred->cr_prison && 1433 info->cred->cr_prison != p->p_ucred->cr_prison) { 1434 return(0); 1435 } 1436 1437 /* 1438 * If the controlling terminal of the process matches the 1439 * vnode being revoked we clear the controlling terminal. 1440 * 1441 * The normal spec_close() may not catch this because it 1442 * uses curproc instead of p. 1443 */ 1444 if (p->p_session && info->type == DTYPE_VNODE && 1445 info->data == p->p_session->s_ttyvp) { 1446 p->p_session->s_ttyvp = NULL; 1447 vrele(info->data); 1448 } 1449 1450 /* 1451 * Softref the fdp to prevent it from being destroyed 1452 */ 1453 spin_lock(&p->p_spin); 1454 if ((fdp = p->p_fd) == NULL) { 1455 spin_unlock(&p->p_spin); 1456 return(0); 1457 } 1458 atomic_add_int(&fdp->fd_softrefs, 1); 1459 spin_unlock(&p->p_spin); 1460 1461 /* 1462 * Locate and close any matching file descriptors. 1463 */ 1464 spin_lock(&fdp->fd_spin); 1465 for (n = 0; n < fdp->fd_nfiles; ++n) { 1466 if ((fp = fdp->fd_files[n].fp) == NULL) 1467 continue; 1468 if (fp->f_flag & FREVOKED) { 1469 fhold(info->nfp); 1470 fdp->fd_files[n].fp = info->nfp; 1471 spin_unlock(&fdp->fd_spin); 1472 knote_fdclose(fp, fdp, n); /* XXX */ 1473 closef(fp, p); 1474 spin_lock(&fdp->fd_spin); 1475 --info->count; 1476 } 1477 } 1478 spin_unlock(&fdp->fd_spin); 1479 atomic_subtract_int(&fdp->fd_softrefs, 1); 1480 return(0); 1481 } 1482 1483 /* 1484 * falloc: 1485 * Create a new open file structure and reserve a file decriptor 1486 * for the process that refers to it. 1487 * 1488 * Root creds are checked using lp, or assumed if lp is NULL. If 1489 * resultfd is non-NULL then lp must also be non-NULL. No file 1490 * descriptor is reserved (and no process context is needed) if 1491 * resultfd is NULL. 1492 * 1493 * A file pointer with a refcount of 1 is returned. Note that the 1494 * file pointer is NOT associated with the descriptor. If falloc 1495 * returns success, fsetfd() MUST be called to either associate the 1496 * file pointer or clear the reservation. 1497 * 1498 * MPSAFE 1499 */ 1500 int 1501 falloc(struct lwp *lp, struct file **resultfp, int *resultfd) 1502 { 1503 static struct timeval lastfail; 1504 static int curfail; 1505 struct file *fp; 1506 struct ucred *cred = lp ? lp->lwp_thread->td_ucred : proc0.p_ucred; 1507 int error; 1508 1509 fp = NULL; 1510 1511 /* 1512 * Handle filetable full issues and root overfill. 1513 */ 1514 if (nfiles >= maxfiles - maxfilesrootres && 1515 (cred->cr_ruid != 0 || nfiles >= maxfiles)) { 1516 if (ppsratecheck(&lastfail, &curfail, 1)) { 1517 kprintf("kern.maxfiles limit exceeded by uid %d, " 1518 "please see tuning(7).\n", 1519 cred->cr_ruid); 1520 } 1521 error = ENFILE; 1522 goto done; 1523 } 1524 1525 /* 1526 * Allocate a new file descriptor. 1527 */ 1528 fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 1529 spin_init(&fp->f_spin); 1530 SLIST_INIT(&fp->f_klist); 1531 fp->f_count = 1; 1532 fp->f_ops = &badfileops; 1533 fp->f_seqcount = 1; 1534 fsetcred(fp, cred); 1535 spin_lock(&filehead_spin); 1536 nfiles++; 1537 LIST_INSERT_HEAD(&filehead, fp, f_list); 1538 spin_unlock(&filehead_spin); 1539 if (resultfd) { 1540 if ((error = fdalloc(lp->lwp_proc, 0, resultfd)) != 0) { 1541 fdrop(fp); 1542 fp = NULL; 1543 } 1544 } else { 1545 error = 0; 1546 } 1547 done: 1548 *resultfp = fp; 1549 return (error); 1550 } 1551 1552 /* 1553 * Check for races against a file descriptor by determining that the 1554 * file pointer is still associated with the specified file descriptor, 1555 * and a close is not currently in progress. 1556 * 1557 * MPSAFE 1558 */ 1559 int 1560 checkfdclosed(struct filedesc *fdp, int fd, struct file *fp) 1561 { 1562 int error; 1563 1564 spin_lock_shared(&fdp->fd_spin); 1565 if ((unsigned)fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) 1566 error = EBADF; 1567 else 1568 error = 0; 1569 spin_unlock_shared(&fdp->fd_spin); 1570 return (error); 1571 } 1572 1573 /* 1574 * Associate a file pointer with a previously reserved file descriptor. 1575 * This function always succeeds. 1576 * 1577 * If fp is NULL, the file descriptor is returned to the pool. 1578 */ 1579 1580 /* 1581 * MPSAFE (exclusive spinlock must be held on call) 1582 */ 1583 static void 1584 fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) 1585 { 1586 KKASSERT((unsigned)fd < fdp->fd_nfiles); 1587 KKASSERT(fdp->fd_files[fd].reserved != 0); 1588 if (fp) { 1589 fhold(fp); 1590 fdp->fd_files[fd].fp = fp; 1591 fdp->fd_files[fd].reserved = 0; 1592 } else { 1593 fdp->fd_files[fd].reserved = 0; 1594 fdreserve_locked(fdp, fd, -1); 1595 fdfixup_locked(fdp, fd); 1596 } 1597 } 1598 1599 /* 1600 * MPSAFE 1601 */ 1602 void 1603 fsetfd(struct filedesc *fdp, struct file *fp, int fd) 1604 { 1605 spin_lock(&fdp->fd_spin); 1606 fsetfd_locked(fdp, fp, fd); 1607 spin_unlock(&fdp->fd_spin); 1608 } 1609 1610 /* 1611 * MPSAFE (exclusive spinlock must be held on call) 1612 */ 1613 static 1614 struct file * 1615 funsetfd_locked(struct filedesc *fdp, int fd) 1616 { 1617 struct file *fp; 1618 1619 if ((unsigned)fd >= fdp->fd_nfiles) 1620 return (NULL); 1621 if ((fp = fdp->fd_files[fd].fp) == NULL) 1622 return (NULL); 1623 fdp->fd_files[fd].fp = NULL; 1624 fdp->fd_files[fd].fileflags = 0; 1625 1626 fdreserve_locked(fdp, fd, -1); 1627 fdfixup_locked(fdp, fd); 1628 return(fp); 1629 } 1630 1631 /* 1632 * MPSAFE 1633 */ 1634 int 1635 fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) 1636 { 1637 int error; 1638 1639 spin_lock(&fdp->fd_spin); 1640 if (((u_int)fd) >= fdp->fd_nfiles) { 1641 error = EBADF; 1642 } else if (fdp->fd_files[fd].fp == NULL) { 1643 error = EBADF; 1644 } else { 1645 *flagsp = fdp->fd_files[fd].fileflags; 1646 error = 0; 1647 } 1648 spin_unlock(&fdp->fd_spin); 1649 return (error); 1650 } 1651 1652 /* 1653 * MPSAFE 1654 */ 1655 int 1656 fsetfdflags(struct filedesc *fdp, int fd, int add_flags) 1657 { 1658 int error; 1659 1660 spin_lock(&fdp->fd_spin); 1661 if (((u_int)fd) >= fdp->fd_nfiles) { 1662 error = EBADF; 1663 } else if (fdp->fd_files[fd].fp == NULL) { 1664 error = EBADF; 1665 } else { 1666 fdp->fd_files[fd].fileflags |= add_flags; 1667 error = 0; 1668 } 1669 spin_unlock(&fdp->fd_spin); 1670 return (error); 1671 } 1672 1673 /* 1674 * MPSAFE 1675 */ 1676 int 1677 fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) 1678 { 1679 int error; 1680 1681 spin_lock(&fdp->fd_spin); 1682 if (((u_int)fd) >= fdp->fd_nfiles) { 1683 error = EBADF; 1684 } else if (fdp->fd_files[fd].fp == NULL) { 1685 error = EBADF; 1686 } else { 1687 fdp->fd_files[fd].fileflags &= ~rem_flags; 1688 error = 0; 1689 } 1690 spin_unlock(&fdp->fd_spin); 1691 return (error); 1692 } 1693 1694 /* 1695 * Set/Change/Clear the creds for a fp and synchronize the uidinfo. 1696 */ 1697 void 1698 fsetcred(struct file *fp, struct ucred *ncr) 1699 { 1700 struct ucred *ocr; 1701 struct uidinfo *uip; 1702 1703 ocr = fp->f_cred; 1704 if (ocr == NULL || ncr == NULL || ocr->cr_uidinfo != ncr->cr_uidinfo) { 1705 if (ocr) { 1706 uip = ocr->cr_uidinfo; 1707 atomic_add_int(&uip->ui_openfiles, -1); 1708 } 1709 if (ncr) { 1710 uip = ncr->cr_uidinfo; 1711 atomic_add_int(&uip->ui_openfiles, 1); 1712 } 1713 } 1714 if (ncr) 1715 crhold(ncr); 1716 fp->f_cred = ncr; 1717 if (ocr) 1718 crfree(ocr); 1719 } 1720 1721 /* 1722 * Free a file descriptor. 1723 */ 1724 static 1725 void 1726 ffree(struct file *fp) 1727 { 1728 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 1729 spin_lock(&filehead_spin); 1730 LIST_REMOVE(fp, f_list); 1731 nfiles--; 1732 spin_unlock(&filehead_spin); 1733 fsetcred(fp, NULL); 1734 if (fp->f_nchandle.ncp) 1735 cache_drop(&fp->f_nchandle); 1736 kfree(fp, M_FILE); 1737 } 1738 1739 /* 1740 * called from init_main, initialize filedesc0 for proc0. 1741 */ 1742 void 1743 fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) 1744 { 1745 p0->p_fd = fdp0; 1746 p0->p_fdtol = NULL; 1747 fdp0->fd_refcnt = 1; 1748 fdp0->fd_cmask = cmask; 1749 fdp0->fd_files = fdp0->fd_builtin_files; 1750 fdp0->fd_nfiles = NDFILE; 1751 fdp0->fd_lastfile = -1; 1752 spin_init(&fdp0->fd_spin); 1753 } 1754 1755 /* 1756 * Build a new filedesc structure. 1757 * 1758 * NOT MPSAFE (vref) 1759 */ 1760 struct filedesc * 1761 fdinit(struct proc *p) 1762 { 1763 struct filedesc *newfdp; 1764 struct filedesc *fdp = p->p_fd; 1765 1766 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); 1767 spin_lock(&fdp->fd_spin); 1768 if (fdp->fd_cdir) { 1769 newfdp->fd_cdir = fdp->fd_cdir; 1770 vref(newfdp->fd_cdir); 1771 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1772 } 1773 1774 /* 1775 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 1776 * proc0, but should unconditionally exist in other processes. 1777 */ 1778 if (fdp->fd_rdir) { 1779 newfdp->fd_rdir = fdp->fd_rdir; 1780 vref(newfdp->fd_rdir); 1781 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1782 } 1783 if (fdp->fd_jdir) { 1784 newfdp->fd_jdir = fdp->fd_jdir; 1785 vref(newfdp->fd_jdir); 1786 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1787 } 1788 spin_unlock(&fdp->fd_spin); 1789 1790 /* Create the file descriptor table. */ 1791 newfdp->fd_refcnt = 1; 1792 newfdp->fd_cmask = cmask; 1793 newfdp->fd_files = newfdp->fd_builtin_files; 1794 newfdp->fd_nfiles = NDFILE; 1795 newfdp->fd_lastfile = -1; 1796 spin_init(&newfdp->fd_spin); 1797 1798 return (newfdp); 1799 } 1800 1801 /* 1802 * Share a filedesc structure. 1803 * 1804 * MPSAFE 1805 */ 1806 struct filedesc * 1807 fdshare(struct proc *p) 1808 { 1809 struct filedesc *fdp; 1810 1811 fdp = p->p_fd; 1812 spin_lock(&fdp->fd_spin); 1813 fdp->fd_refcnt++; 1814 spin_unlock(&fdp->fd_spin); 1815 return (fdp); 1816 } 1817 1818 /* 1819 * Copy a filedesc structure. 1820 * 1821 * MPSAFE 1822 */ 1823 int 1824 fdcopy(struct proc *p, struct filedesc **fpp) 1825 { 1826 struct filedesc *fdp = p->p_fd; 1827 struct filedesc *newfdp; 1828 struct fdnode *fdnode; 1829 int i; 1830 int ni; 1831 1832 /* 1833 * Certain daemons might not have file descriptors. 1834 */ 1835 if (fdp == NULL) 1836 return (0); 1837 1838 /* 1839 * Allocate the new filedesc and fd_files[] array. This can race 1840 * with operations by other threads on the fdp so we have to be 1841 * careful. 1842 */ 1843 newfdp = kmalloc(sizeof(struct filedesc), 1844 M_FILEDESC, M_WAITOK | M_ZERO | M_NULLOK); 1845 if (newfdp == NULL) { 1846 *fpp = NULL; 1847 return (-1); 1848 } 1849 again: 1850 spin_lock(&fdp->fd_spin); 1851 if (fdp->fd_lastfile < NDFILE) { 1852 newfdp->fd_files = newfdp->fd_builtin_files; 1853 i = NDFILE; 1854 } else { 1855 /* 1856 * We have to allocate (N^2-1) entries for our in-place 1857 * binary tree. Allow the table to shrink. 1858 */ 1859 i = fdp->fd_nfiles; 1860 ni = (i - 1) / 2; 1861 while (ni > fdp->fd_lastfile && ni > NDFILE) { 1862 i = ni; 1863 ni = (i - 1) / 2; 1864 } 1865 spin_unlock(&fdp->fd_spin); 1866 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), 1867 M_FILEDESC, M_WAITOK | M_ZERO); 1868 1869 /* 1870 * Check for race, retry 1871 */ 1872 spin_lock(&fdp->fd_spin); 1873 if (i <= fdp->fd_lastfile) { 1874 spin_unlock(&fdp->fd_spin); 1875 kfree(newfdp->fd_files, M_FILEDESC); 1876 goto again; 1877 } 1878 } 1879 1880 /* 1881 * Dup the remaining fields. vref() and cache_hold() can be 1882 * safely called while holding the read spinlock on fdp. 1883 * 1884 * The read spinlock on fdp is still being held. 1885 * 1886 * NOTE: vref and cache_hold calls for the case where the vnode 1887 * or cache entry already has at least one ref may be called 1888 * while holding spin locks. 1889 */ 1890 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { 1891 vref(newfdp->fd_cdir); 1892 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1893 } 1894 /* 1895 * We must check for fd_rdir here, at least for now because 1896 * the init process is created before we have access to the 1897 * rootvode to take a reference to it. 1898 */ 1899 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { 1900 vref(newfdp->fd_rdir); 1901 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1902 } 1903 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { 1904 vref(newfdp->fd_jdir); 1905 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1906 } 1907 newfdp->fd_refcnt = 1; 1908 newfdp->fd_nfiles = i; 1909 newfdp->fd_lastfile = fdp->fd_lastfile; 1910 newfdp->fd_freefile = fdp->fd_freefile; 1911 newfdp->fd_cmask = fdp->fd_cmask; 1912 spin_init(&newfdp->fd_spin); 1913 1914 /* 1915 * Copy the descriptor table through (i). This also copies the 1916 * allocation state. Then go through and ref the file pointers 1917 * and clean up any KQ descriptors. 1918 * 1919 * kq descriptors cannot be copied. Since we haven't ref'd the 1920 * copied files yet we can ignore the return value from funsetfd(). 1921 * 1922 * The read spinlock on fdp is still being held. 1923 */ 1924 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); 1925 for (i = 0 ; i < newfdp->fd_nfiles; ++i) { 1926 fdnode = &newfdp->fd_files[i]; 1927 if (fdnode->reserved) { 1928 fdreserve_locked(newfdp, i, -1); 1929 fdnode->reserved = 0; 1930 fdfixup_locked(newfdp, i); 1931 } else if (fdnode->fp) { 1932 if (fdnode->fp->f_type == DTYPE_KQUEUE) { 1933 (void)funsetfd_locked(newfdp, i); 1934 } else { 1935 fhold(fdnode->fp); 1936 } 1937 } 1938 } 1939 spin_unlock(&fdp->fd_spin); 1940 *fpp = newfdp; 1941 return (0); 1942 } 1943 1944 /* 1945 * Release a filedesc structure. 1946 * 1947 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) 1948 */ 1949 void 1950 fdfree(struct proc *p, struct filedesc *repl) 1951 { 1952 struct filedesc *fdp; 1953 struct fdnode *fdnode; 1954 int i; 1955 struct filedesc_to_leader *fdtol; 1956 struct file *fp; 1957 struct vnode *vp; 1958 struct flock lf; 1959 1960 /* 1961 * Certain daemons might not have file descriptors. 1962 */ 1963 fdp = p->p_fd; 1964 if (fdp == NULL) { 1965 p->p_fd = repl; 1966 return; 1967 } 1968 1969 /* 1970 * Severe messing around to follow. 1971 */ 1972 spin_lock(&fdp->fd_spin); 1973 1974 /* Check for special need to clear POSIX style locks */ 1975 fdtol = p->p_fdtol; 1976 if (fdtol != NULL) { 1977 KASSERT(fdtol->fdl_refcount > 0, 1978 ("filedesc_to_refcount botch: fdl_refcount=%d", 1979 fdtol->fdl_refcount)); 1980 if (fdtol->fdl_refcount == 1 && 1981 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 1982 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1983 fdnode = &fdp->fd_files[i]; 1984 if (fdnode->fp == NULL || 1985 fdnode->fp->f_type != DTYPE_VNODE) { 1986 continue; 1987 } 1988 fp = fdnode->fp; 1989 fhold(fp); 1990 spin_unlock(&fdp->fd_spin); 1991 1992 lf.l_whence = SEEK_SET; 1993 lf.l_start = 0; 1994 lf.l_len = 0; 1995 lf.l_type = F_UNLCK; 1996 vp = (struct vnode *)fp->f_data; 1997 (void) VOP_ADVLOCK(vp, 1998 (caddr_t)p->p_leader, 1999 F_UNLCK, 2000 &lf, 2001 F_POSIX); 2002 fdrop(fp); 2003 spin_lock(&fdp->fd_spin); 2004 } 2005 } 2006 retry: 2007 if (fdtol->fdl_refcount == 1) { 2008 if (fdp->fd_holdleaderscount > 0 && 2009 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 2010 /* 2011 * close() or do_dup() has cleared a reference 2012 * in a shared file descriptor table. 2013 */ 2014 fdp->fd_holdleaderswakeup = 1; 2015 ssleep(&fdp->fd_holdleaderscount, 2016 &fdp->fd_spin, 0, "fdlhold", 0); 2017 goto retry; 2018 } 2019 if (fdtol->fdl_holdcount > 0) { 2020 /* 2021 * Ensure that fdtol->fdl_leader 2022 * remains valid in closef(). 2023 */ 2024 fdtol->fdl_wakeup = 1; 2025 ssleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); 2026 goto retry; 2027 } 2028 } 2029 fdtol->fdl_refcount--; 2030 if (fdtol->fdl_refcount == 0 && 2031 fdtol->fdl_holdcount == 0) { 2032 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2033 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2034 } else { 2035 fdtol = NULL; 2036 } 2037 p->p_fdtol = NULL; 2038 if (fdtol != NULL) { 2039 spin_unlock(&fdp->fd_spin); 2040 kfree(fdtol, M_FILEDESC_TO_LEADER); 2041 spin_lock(&fdp->fd_spin); 2042 } 2043 } 2044 if (--fdp->fd_refcnt > 0) { 2045 spin_unlock(&fdp->fd_spin); 2046 spin_lock(&p->p_spin); 2047 p->p_fd = repl; 2048 spin_unlock(&p->p_spin); 2049 return; 2050 } 2051 2052 /* 2053 * Even though we are the last reference to the structure allproc 2054 * scans may still reference the structure. Maintain proper 2055 * locks until we can replace p->p_fd. 2056 * 2057 * Also note that kqueue's closef still needs to reference the 2058 * fdp via p->p_fd, so we have to close the descriptors before 2059 * we replace p->p_fd. 2060 */ 2061 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2062 if (fdp->fd_files[i].fp) { 2063 fp = funsetfd_locked(fdp, i); 2064 if (fp) { 2065 spin_unlock(&fdp->fd_spin); 2066 if (SLIST_FIRST(&fp->f_klist)) 2067 knote_fdclose(fp, fdp, i); 2068 closef(fp, p); 2069 spin_lock(&fdp->fd_spin); 2070 } 2071 } 2072 } 2073 spin_unlock(&fdp->fd_spin); 2074 2075 /* 2076 * Interlock against an allproc scan operations (typically frevoke). 2077 */ 2078 spin_lock(&p->p_spin); 2079 p->p_fd = repl; 2080 spin_unlock(&p->p_spin); 2081 2082 /* 2083 * Wait for any softrefs to go away. This race rarely occurs so 2084 * we can use a non-critical-path style poll/sleep loop. The 2085 * race only occurs against allproc scans. 2086 * 2087 * No new softrefs can occur with the fdp disconnected from the 2088 * process. 2089 */ 2090 if (fdp->fd_softrefs) { 2091 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid); 2092 while (fdp->fd_softrefs) 2093 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1); 2094 } 2095 2096 if (fdp->fd_files != fdp->fd_builtin_files) 2097 kfree(fdp->fd_files, M_FILEDESC); 2098 if (fdp->fd_cdir) { 2099 cache_drop(&fdp->fd_ncdir); 2100 vrele(fdp->fd_cdir); 2101 } 2102 if (fdp->fd_rdir) { 2103 cache_drop(&fdp->fd_nrdir); 2104 vrele(fdp->fd_rdir); 2105 } 2106 if (fdp->fd_jdir) { 2107 cache_drop(&fdp->fd_njdir); 2108 vrele(fdp->fd_jdir); 2109 } 2110 kfree(fdp, M_FILEDESC); 2111 } 2112 2113 /* 2114 * Retrieve and reference the file pointer associated with a descriptor. 2115 * 2116 * MPSAFE 2117 */ 2118 struct file * 2119 holdfp(struct filedesc *fdp, int fd, int flag) 2120 { 2121 struct file* fp; 2122 2123 spin_lock_shared(&fdp->fd_spin); 2124 if (((u_int)fd) >= fdp->fd_nfiles) { 2125 fp = NULL; 2126 goto done; 2127 } 2128 if ((fp = fdp->fd_files[fd].fp) == NULL) 2129 goto done; 2130 if ((fp->f_flag & flag) == 0 && flag != -1) { 2131 fp = NULL; 2132 goto done; 2133 } 2134 fhold(fp); 2135 done: 2136 spin_unlock_shared(&fdp->fd_spin); 2137 return (fp); 2138 } 2139 2140 /* 2141 * holdsock() - load the struct file pointer associated 2142 * with a socket into *fpp. If an error occurs, non-zero 2143 * will be returned and *fpp will be set to NULL. 2144 * 2145 * MPSAFE 2146 */ 2147 int 2148 holdsock(struct filedesc *fdp, int fd, struct file **fpp) 2149 { 2150 struct file *fp; 2151 int error; 2152 2153 spin_lock_shared(&fdp->fd_spin); 2154 if ((unsigned)fd >= fdp->fd_nfiles) { 2155 error = EBADF; 2156 fp = NULL; 2157 goto done; 2158 } 2159 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2160 error = EBADF; 2161 goto done; 2162 } 2163 if (fp->f_type != DTYPE_SOCKET) { 2164 error = ENOTSOCK; 2165 goto done; 2166 } 2167 fhold(fp); 2168 error = 0; 2169 done: 2170 spin_unlock_shared(&fdp->fd_spin); 2171 *fpp = fp; 2172 return (error); 2173 } 2174 2175 /* 2176 * Convert a user file descriptor to a held file pointer. 2177 * 2178 * MPSAFE 2179 */ 2180 int 2181 holdvnode(struct filedesc *fdp, int fd, struct file **fpp) 2182 { 2183 struct file *fp; 2184 int error; 2185 2186 spin_lock_shared(&fdp->fd_spin); 2187 if ((unsigned)fd >= fdp->fd_nfiles) { 2188 error = EBADF; 2189 fp = NULL; 2190 goto done; 2191 } 2192 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2193 error = EBADF; 2194 goto done; 2195 } 2196 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2197 fp = NULL; 2198 error = EINVAL; 2199 goto done; 2200 } 2201 fhold(fp); 2202 error = 0; 2203 done: 2204 spin_unlock_shared(&fdp->fd_spin); 2205 *fpp = fp; 2206 return (error); 2207 } 2208 2209 /* 2210 * For setugid programs, we don't want to people to use that setugidness 2211 * to generate error messages which write to a file which otherwise would 2212 * otherwise be off-limits to the process. 2213 * 2214 * This is a gross hack to plug the hole. A better solution would involve 2215 * a special vop or other form of generalized access control mechanism. We 2216 * go ahead and just reject all procfs file systems accesses as dangerous. 2217 * 2218 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 2219 * sufficient. We also don't for check setugidness since we know we are. 2220 */ 2221 static int 2222 is_unsafe(struct file *fp) 2223 { 2224 if (fp->f_type == DTYPE_VNODE && 2225 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 2226 return (1); 2227 return (0); 2228 } 2229 2230 /* 2231 * Make this setguid thing safe, if at all possible. 2232 * 2233 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2234 */ 2235 void 2236 setugidsafety(struct proc *p) 2237 { 2238 struct filedesc *fdp = p->p_fd; 2239 int i; 2240 2241 /* Certain daemons might not have file descriptors. */ 2242 if (fdp == NULL) 2243 return; 2244 2245 /* 2246 * note: fdp->fd_files may be reallocated out from under us while 2247 * we are blocked in a close. Be careful! 2248 */ 2249 for (i = 0; i <= fdp->fd_lastfile; i++) { 2250 if (i > 2) 2251 break; 2252 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { 2253 struct file *fp; 2254 2255 /* 2256 * NULL-out descriptor prior to close to avoid 2257 * a race while close blocks. 2258 */ 2259 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2260 knote_fdclose(fp, fdp, i); 2261 closef(fp, p); 2262 } 2263 } 2264 } 2265 } 2266 2267 /* 2268 * Close any files on exec? 2269 * 2270 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2271 */ 2272 void 2273 fdcloseexec(struct proc *p) 2274 { 2275 struct filedesc *fdp = p->p_fd; 2276 int i; 2277 2278 /* Certain daemons might not have file descriptors. */ 2279 if (fdp == NULL) 2280 return; 2281 2282 /* 2283 * We cannot cache fd_files since operations may block and rip 2284 * them out from under us. 2285 */ 2286 for (i = 0; i <= fdp->fd_lastfile; i++) { 2287 if (fdp->fd_files[i].fp != NULL && 2288 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { 2289 struct file *fp; 2290 2291 /* 2292 * NULL-out descriptor prior to close to avoid 2293 * a race while close blocks. 2294 */ 2295 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2296 knote_fdclose(fp, fdp, i); 2297 closef(fp, p); 2298 } 2299 } 2300 } 2301 } 2302 2303 /* 2304 * It is unsafe for set[ug]id processes to be started with file 2305 * descriptors 0..2 closed, as these descriptors are given implicit 2306 * significance in the Standard C library. fdcheckstd() will create a 2307 * descriptor referencing /dev/null for each of stdin, stdout, and 2308 * stderr that is not already open. 2309 * 2310 * NOT MPSAFE - calls falloc, vn_open, etc 2311 */ 2312 int 2313 fdcheckstd(struct lwp *lp) 2314 { 2315 struct nlookupdata nd; 2316 struct filedesc *fdp; 2317 struct file *fp; 2318 int retval; 2319 int i, error, flags, devnull; 2320 2321 fdp = lp->lwp_proc->p_fd; 2322 if (fdp == NULL) 2323 return (0); 2324 devnull = -1; 2325 error = 0; 2326 for (i = 0; i < 3; i++) { 2327 if (fdp->fd_files[i].fp != NULL) 2328 continue; 2329 if (devnull < 0) { 2330 if ((error = falloc(lp, &fp, &devnull)) != 0) 2331 break; 2332 2333 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 2334 NLC_FOLLOW|NLC_LOCKVP); 2335 flags = FREAD | FWRITE; 2336 if (error == 0) 2337 error = vn_open(&nd, fp, flags, 0); 2338 if (error == 0) 2339 fsetfd(fdp, fp, devnull); 2340 else 2341 fsetfd(fdp, NULL, devnull); 2342 fdrop(fp); 2343 nlookup_done(&nd); 2344 if (error) 2345 break; 2346 KKASSERT(i == devnull); 2347 } else { 2348 error = kern_dup(DUP_FIXED, devnull, i, &retval); 2349 if (error != 0) 2350 break; 2351 } 2352 } 2353 return (error); 2354 } 2355 2356 /* 2357 * Internal form of close. 2358 * Decrement reference count on file structure. 2359 * Note: td and/or p may be NULL when closing a file 2360 * that was being passed in a message. 2361 * 2362 * MPALMOSTSAFE - acquires mplock for VOP operations 2363 */ 2364 int 2365 closef(struct file *fp, struct proc *p) 2366 { 2367 struct vnode *vp; 2368 struct flock lf; 2369 struct filedesc_to_leader *fdtol; 2370 2371 if (fp == NULL) 2372 return (0); 2373 2374 /* 2375 * POSIX record locking dictates that any close releases ALL 2376 * locks owned by this process. This is handled by setting 2377 * a flag in the unlock to free ONLY locks obeying POSIX 2378 * semantics, and not to free BSD-style file locks. 2379 * If the descriptor was in a message, POSIX-style locks 2380 * aren't passed with the descriptor. 2381 */ 2382 if (p != NULL && fp->f_type == DTYPE_VNODE && 2383 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2384 ) { 2385 if ((p->p_leader->p_flags & P_ADVLOCK) != 0) { 2386 lf.l_whence = SEEK_SET; 2387 lf.l_start = 0; 2388 lf.l_len = 0; 2389 lf.l_type = F_UNLCK; 2390 vp = (struct vnode *)fp->f_data; 2391 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 2392 &lf, F_POSIX); 2393 } 2394 fdtol = p->p_fdtol; 2395 if (fdtol != NULL) { 2396 lwkt_gettoken(&p->p_token); 2397 /* 2398 * Handle special case where file descriptor table 2399 * is shared between multiple process leaders. 2400 */ 2401 for (fdtol = fdtol->fdl_next; 2402 fdtol != p->p_fdtol; 2403 fdtol = fdtol->fdl_next) { 2404 if ((fdtol->fdl_leader->p_flags & 2405 P_ADVLOCK) == 0) 2406 continue; 2407 fdtol->fdl_holdcount++; 2408 lf.l_whence = SEEK_SET; 2409 lf.l_start = 0; 2410 lf.l_len = 0; 2411 lf.l_type = F_UNLCK; 2412 vp = (struct vnode *)fp->f_data; 2413 (void) VOP_ADVLOCK(vp, 2414 (caddr_t)fdtol->fdl_leader, 2415 F_UNLCK, &lf, F_POSIX); 2416 fdtol->fdl_holdcount--; 2417 if (fdtol->fdl_holdcount == 0 && 2418 fdtol->fdl_wakeup != 0) { 2419 fdtol->fdl_wakeup = 0; 2420 wakeup(fdtol); 2421 } 2422 } 2423 lwkt_reltoken(&p->p_token); 2424 } 2425 } 2426 return (fdrop(fp)); 2427 } 2428 2429 /* 2430 * MPSAFE 2431 * 2432 * fhold() can only be called if f_count is already at least 1 (i.e. the 2433 * caller of fhold() already has a reference to the file pointer in some 2434 * manner or other). 2435 * 2436 * f_count is not spin-locked. Instead, atomic ops are used for 2437 * incrementing, decrementing, and handling the 1->0 transition. 2438 */ 2439 void 2440 fhold(struct file *fp) 2441 { 2442 atomic_add_int(&fp->f_count, 1); 2443 } 2444 2445 /* 2446 * fdrop() - drop a reference to a descriptor 2447 * 2448 * MPALMOSTSAFE - acquires mplock for final close sequence 2449 */ 2450 int 2451 fdrop(struct file *fp) 2452 { 2453 struct flock lf; 2454 struct vnode *vp; 2455 int error; 2456 2457 /* 2458 * A combined fetch and subtract is needed to properly detect 2459 * 1->0 transitions, otherwise two cpus dropping from a ref 2460 * count of 2 might both try to run the 1->0 code. 2461 */ 2462 if (atomic_fetchadd_int(&fp->f_count, -1) > 1) 2463 return (0); 2464 2465 KKASSERT(SLIST_FIRST(&fp->f_klist) == NULL); 2466 2467 /* 2468 * The last reference has gone away, we own the fp structure free 2469 * and clear. 2470 */ 2471 if (fp->f_count < 0) 2472 panic("fdrop: count < 0"); 2473 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && 2474 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2475 ) { 2476 lf.l_whence = SEEK_SET; 2477 lf.l_start = 0; 2478 lf.l_len = 0; 2479 lf.l_type = F_UNLCK; 2480 vp = (struct vnode *)fp->f_data; 2481 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2482 } 2483 if (fp->f_ops != &badfileops) 2484 error = fo_close(fp); 2485 else 2486 error = 0; 2487 ffree(fp); 2488 return (error); 2489 } 2490 2491 /* 2492 * Apply an advisory lock on a file descriptor. 2493 * 2494 * Just attempt to get a record lock of the requested type on 2495 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2496 * 2497 * MPALMOSTSAFE 2498 */ 2499 int 2500 sys_flock(struct flock_args *uap) 2501 { 2502 struct proc *p = curproc; 2503 struct file *fp; 2504 struct vnode *vp; 2505 struct flock lf; 2506 int error; 2507 2508 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 2509 return (EBADF); 2510 if (fp->f_type != DTYPE_VNODE) { 2511 error = EOPNOTSUPP; 2512 goto done; 2513 } 2514 vp = (struct vnode *)fp->f_data; 2515 lf.l_whence = SEEK_SET; 2516 lf.l_start = 0; 2517 lf.l_len = 0; 2518 if (uap->how & LOCK_UN) { 2519 lf.l_type = F_UNLCK; 2520 fp->f_flag &= ~FHASLOCK; 2521 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2522 goto done; 2523 } 2524 if (uap->how & LOCK_EX) 2525 lf.l_type = F_WRLCK; 2526 else if (uap->how & LOCK_SH) 2527 lf.l_type = F_RDLCK; 2528 else { 2529 error = EBADF; 2530 goto done; 2531 } 2532 fp->f_flag |= FHASLOCK; 2533 if (uap->how & LOCK_NB) 2534 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); 2535 else 2536 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); 2537 done: 2538 fdrop(fp); 2539 return (error); 2540 } 2541 2542 /* 2543 * File Descriptor pseudo-device driver (/dev/fd/). 2544 * 2545 * Opening minor device N dup()s the file (if any) connected to file 2546 * descriptor N belonging to the calling process. Note that this driver 2547 * consists of only the ``open()'' routine, because all subsequent 2548 * references to this file will be direct to the other driver. 2549 */ 2550 static int 2551 fdopen(struct dev_open_args *ap) 2552 { 2553 thread_t td = curthread; 2554 2555 KKASSERT(td->td_lwp != NULL); 2556 2557 /* 2558 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the 2559 * the file descriptor being sought for duplication. The error 2560 * return ensures that the vnode for this device will be released 2561 * by vn_open. Open will detect this special error and take the 2562 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2563 * will simply report the error. 2564 */ 2565 td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev); 2566 return (ENODEV); 2567 } 2568 2569 /* 2570 * The caller has reserved the file descriptor dfd for us. On success we 2571 * must fsetfd() it. On failure the caller will clean it up. 2572 * 2573 * MPSAFE 2574 */ 2575 int 2576 dupfdopen(struct filedesc *fdp, int dfd, int sfd, int mode, int error) 2577 { 2578 struct file *wfp; 2579 struct file *xfp; 2580 int werror; 2581 2582 if ((wfp = holdfp(fdp, sfd, -1)) == NULL) 2583 return (EBADF); 2584 2585 /* 2586 * Close a revoke/dup race. Duping a descriptor marked as revoked 2587 * will dup a dummy descriptor instead of the real one. 2588 */ 2589 if (wfp->f_flag & FREVOKED) { 2590 kprintf("Warning: attempt to dup() a revoked descriptor\n"); 2591 fdrop(wfp); 2592 wfp = NULL; 2593 werror = falloc(NULL, &wfp, NULL); 2594 if (werror) 2595 return (werror); 2596 } 2597 2598 /* 2599 * There are two cases of interest here. 2600 * 2601 * For ENODEV simply dup sfd to file descriptor dfd and return. 2602 * 2603 * For ENXIO steal away the file structure from sfd and store it 2604 * dfd. sfd is effectively closed by this operation. 2605 * 2606 * Any other error code is just returned. 2607 */ 2608 switch (error) { 2609 case ENODEV: 2610 /* 2611 * Check that the mode the file is being opened for is a 2612 * subset of the mode of the existing descriptor. 2613 */ 2614 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2615 error = EACCES; 2616 break; 2617 } 2618 spin_lock(&fdp->fd_spin); 2619 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2620 fsetfd_locked(fdp, wfp, dfd); 2621 spin_unlock(&fdp->fd_spin); 2622 error = 0; 2623 break; 2624 case ENXIO: 2625 /* 2626 * Steal away the file pointer from dfd, and stuff it into indx. 2627 */ 2628 spin_lock(&fdp->fd_spin); 2629 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2630 fsetfd(fdp, wfp, dfd); 2631 if ((xfp = funsetfd_locked(fdp, sfd)) != NULL) { 2632 spin_unlock(&fdp->fd_spin); 2633 fdrop(xfp); 2634 } else { 2635 spin_unlock(&fdp->fd_spin); 2636 } 2637 error = 0; 2638 break; 2639 default: 2640 break; 2641 } 2642 fdrop(wfp); 2643 return (error); 2644 } 2645 2646 /* 2647 * NOT MPSAFE - I think these refer to a common file descriptor table 2648 * and we need to spinlock that to link fdtol in. 2649 */ 2650 struct filedesc_to_leader * 2651 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2652 struct proc *leader) 2653 { 2654 struct filedesc_to_leader *fdtol; 2655 2656 fdtol = kmalloc(sizeof(struct filedesc_to_leader), 2657 M_FILEDESC_TO_LEADER, M_WAITOK | M_ZERO); 2658 fdtol->fdl_refcount = 1; 2659 fdtol->fdl_holdcount = 0; 2660 fdtol->fdl_wakeup = 0; 2661 fdtol->fdl_leader = leader; 2662 if (old != NULL) { 2663 fdtol->fdl_next = old->fdl_next; 2664 fdtol->fdl_prev = old; 2665 old->fdl_next = fdtol; 2666 fdtol->fdl_next->fdl_prev = fdtol; 2667 } else { 2668 fdtol->fdl_next = fdtol; 2669 fdtol->fdl_prev = fdtol; 2670 } 2671 return fdtol; 2672 } 2673 2674 /* 2675 * Scan all file pointers in the system. The callback is made with 2676 * the master list spinlock held exclusively. 2677 * 2678 * MPSAFE 2679 */ 2680 void 2681 allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) 2682 { 2683 struct file *fp; 2684 int res; 2685 2686 spin_lock(&filehead_spin); 2687 LIST_FOREACH(fp, &filehead, f_list) { 2688 res = callback(fp, data); 2689 if (res < 0) 2690 break; 2691 } 2692 spin_unlock(&filehead_spin); 2693 } 2694 2695 /* 2696 * Get file structures. 2697 * 2698 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) 2699 */ 2700 2701 struct sysctl_kern_file_info { 2702 int count; 2703 int error; 2704 struct sysctl_req *req; 2705 }; 2706 2707 static int sysctl_kern_file_callback(struct proc *p, void *data); 2708 2709 static int 2710 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2711 { 2712 struct sysctl_kern_file_info info; 2713 2714 /* 2715 * Note: because the number of file descriptors is calculated 2716 * in different ways for sizing vs returning the data, 2717 * there is information leakage from the first loop. However, 2718 * it is of a similar order of magnitude to the leakage from 2719 * global system statistics such as kern.openfiles. 2720 * 2721 * When just doing a count, note that we cannot just count 2722 * the elements and add f_count via the filehead list because 2723 * threaded processes share their descriptor table and f_count might 2724 * still be '1' in that case. 2725 * 2726 * Since the SYSCTL op can block, we must hold the process to 2727 * prevent it being ripped out from under us either in the 2728 * file descriptor loop or in the greater LIST_FOREACH. The 2729 * process may be in varying states of disrepair. If the process 2730 * is in SZOMB we may have caught it just as it is being removed 2731 * from the allproc list, we must skip it in that case to maintain 2732 * an unbroken chain through the allproc list. 2733 */ 2734 info.count = 0; 2735 info.error = 0; 2736 info.req = req; 2737 allproc_scan(sysctl_kern_file_callback, &info); 2738 2739 /* 2740 * When just calculating the size, overestimate a bit to try to 2741 * prevent system activity from causing the buffer-fill call 2742 * to fail later on. 2743 */ 2744 if (req->oldptr == NULL) { 2745 info.count = (info.count + 16) + (info.count / 10); 2746 info.error = SYSCTL_OUT(req, NULL, 2747 info.count * sizeof(struct kinfo_file)); 2748 } 2749 return (info.error); 2750 } 2751 2752 static int 2753 sysctl_kern_file_callback(struct proc *p, void *data) 2754 { 2755 struct sysctl_kern_file_info *info = data; 2756 struct kinfo_file kf; 2757 struct filedesc *fdp; 2758 struct file *fp; 2759 uid_t uid; 2760 int n; 2761 2762 if (p->p_stat == SIDL || p->p_stat == SZOMB) 2763 return(0); 2764 if (!PRISON_CHECK(info->req->td->td_ucred, p->p_ucred) != 0) 2765 return(0); 2766 2767 /* 2768 * Softref the fdp to prevent it from being destroyed 2769 */ 2770 spin_lock(&p->p_spin); 2771 if ((fdp = p->p_fd) == NULL) { 2772 spin_unlock(&p->p_spin); 2773 return(0); 2774 } 2775 atomic_add_int(&fdp->fd_softrefs, 1); 2776 spin_unlock(&p->p_spin); 2777 2778 /* 2779 * The fdp's own spinlock prevents the contents from being 2780 * modified. 2781 */ 2782 spin_lock_shared(&fdp->fd_spin); 2783 for (n = 0; n < fdp->fd_nfiles; ++n) { 2784 if ((fp = fdp->fd_files[n].fp) == NULL) 2785 continue; 2786 if (info->req->oldptr == NULL) { 2787 ++info->count; 2788 } else { 2789 uid = p->p_ucred ? p->p_ucred->cr_uid : -1; 2790 kcore_make_file(&kf, fp, p->p_pid, uid, n); 2791 spin_unlock_shared(&fdp->fd_spin); 2792 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); 2793 spin_lock_shared(&fdp->fd_spin); 2794 if (info->error) 2795 break; 2796 } 2797 } 2798 spin_unlock_shared(&fdp->fd_spin); 2799 atomic_subtract_int(&fdp->fd_softrefs, 1); 2800 if (info->error) 2801 return(-1); 2802 return(0); 2803 } 2804 2805 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2806 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 2807 2808 SYSCTL_INT(_kern, OID_AUTO, minfilesperproc, CTLFLAG_RW, 2809 &minfilesperproc, 0, "Minimum files allowed open per process"); 2810 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2811 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2812 SYSCTL_INT(_kern, OID_AUTO, maxfilesperuser, CTLFLAG_RW, 2813 &maxfilesperuser, 0, "Maximum files allowed open per user"); 2814 2815 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2816 &maxfiles, 0, "Maximum number of files"); 2817 2818 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 2819 &maxfilesrootres, 0, "Descriptors reserved for root use"); 2820 2821 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2822 &nfiles, 0, "System-wide number of open files"); 2823 2824 static void 2825 fildesc_drvinit(void *unused) 2826 { 2827 int fd; 2828 2829 for (fd = 0; fd < NUMFDESC; fd++) { 2830 make_dev(&fildesc_ops, fd, 2831 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 2832 } 2833 2834 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 2835 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 2836 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 2837 } 2838 2839 /* 2840 * MPSAFE 2841 */ 2842 struct fileops badfileops = { 2843 .fo_read = badfo_readwrite, 2844 .fo_write = badfo_readwrite, 2845 .fo_ioctl = badfo_ioctl, 2846 .fo_kqfilter = badfo_kqfilter, 2847 .fo_stat = badfo_stat, 2848 .fo_close = badfo_close, 2849 .fo_shutdown = badfo_shutdown 2850 }; 2851 2852 int 2853 badfo_readwrite( 2854 struct file *fp, 2855 struct uio *uio, 2856 struct ucred *cred, 2857 int flags 2858 ) { 2859 return (EBADF); 2860 } 2861 2862 int 2863 badfo_ioctl(struct file *fp, u_long com, caddr_t data, 2864 struct ucred *cred, struct sysmsg *msgv) 2865 { 2866 return (EBADF); 2867 } 2868 2869 /* 2870 * Must return an error to prevent registration, typically 2871 * due to a revoked descriptor (file_filtops assigned). 2872 */ 2873 int 2874 badfo_kqfilter(struct file *fp, struct knote *kn) 2875 { 2876 return (EOPNOTSUPP); 2877 } 2878 2879 /* 2880 * MPSAFE 2881 */ 2882 int 2883 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) 2884 { 2885 return (EBADF); 2886 } 2887 2888 /* 2889 * MPSAFE 2890 */ 2891 int 2892 badfo_close(struct file *fp) 2893 { 2894 return (EBADF); 2895 } 2896 2897 /* 2898 * MPSAFE 2899 */ 2900 int 2901 badfo_shutdown(struct file *fp, int how) 2902 { 2903 return (EBADF); 2904 } 2905 2906 /* 2907 * MPSAFE 2908 */ 2909 int 2910 nofo_shutdown(struct file *fp, int how) 2911 { 2912 return (EOPNOTSUPP); 2913 } 2914 2915 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2916 fildesc_drvinit,NULL) 2917