1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 42 #include <sys/param.h> 43 #include <sys/limits.h> 44 #include <sys/systm.h> 45 #include <sys/syscallsubr.h> 46 #include <sys/sysproto.h> 47 #include <sys/conf.h> 48 #include <sys/filedesc.h> 49 #include <sys/lock.h> 50 #include <sys/jail.h> 51 #include <sys/kernel.h> 52 #include <sys/limits.h> 53 #include <sys/malloc.h> 54 #include <sys/mutex.h> 55 #include <sys/sysctl.h> 56 #include <sys/vnode.h> 57 #include <sys/mount.h> 58 #include <sys/proc.h> 59 #include <sys/namei.h> 60 #include <sys/file.h> 61 #include <sys/stat.h> 62 #include <sys/filio.h> 63 #include <sys/fcntl.h> 64 #include <sys/unistd.h> 65 #include <sys/resourcevar.h> 66 #include <sys/event.h> 67 #include <sys/sx.h> 68 #include <sys/socketvar.h> 69 #include <sys/signalvar.h> 70 71 #include <vm/vm.h> 72 #include <vm/vm_extern.h> 73 #include <vm/uma.h> 74 75 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 76 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 77 "file desc to leader structures"); 78 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 79 80 static uma_zone_t file_zone; 81 82 static d_open_t fdopen; 83 #define NUMFDESC 64 84 85 #define CDEV_MAJOR 22 86 static struct cdevsw fildesc_cdevsw = { 87 .d_version = D_VERSION, 88 .d_flags = D_NEEDGIANT, 89 .d_open = fdopen, 90 .d_name = "FD", 91 .d_maj = CDEV_MAJOR, 92 }; 93 94 /* How to treat 'new' parameter when allocating a fd for do_dup(). */ 95 enum dup_type { DUP_VARIABLE, DUP_FIXED }; 96 97 static int do_dup(struct thread *td, enum dup_type type, int old, int new, 98 register_t *retval); 99 static int fd_first_free(struct filedesc *, int, int); 100 static int fd_last_used(struct filedesc *, int, int); 101 static void fdgrowtable(struct filedesc *, int); 102 103 /* 104 * Descriptor management. 105 */ 106 struct filelist filehead; /* head of list of open files */ 107 int nfiles; /* actual number of open files */ 108 struct sx filelist_lock; /* sx to protect filelist */ 109 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 110 111 /* 112 * Find the first zero bit in the given bitmap, starting at low and not 113 * exceeding size - 1. 114 */ 115 static int 116 fd_first_free(struct filedesc *fdp, int low, int size) 117 { 118 NDSLOTTYPE *map = fdp->fd_map; 119 NDSLOTTYPE mask; 120 int off, maxoff; 121 122 if (low >= size) 123 return (low); 124 125 off = NDSLOT(low); 126 if (low % NDENTRIES) { 127 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 128 if ((mask &= ~map[off]) != 0UL) 129 return (off * NDENTRIES + ffsl(mask) - 1); 130 ++off; 131 } 132 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 133 if (map[off] != ~0UL) 134 return (off * NDENTRIES + ffsl(~map[off]) - 1); 135 return (size); 136 } 137 138 /* 139 * Find the highest non-zero bit in the given bitmap, starting at low and 140 * not exceeding size - 1. 141 */ 142 static int 143 fd_last_used(struct filedesc *fdp, int low, int size) 144 { 145 NDSLOTTYPE *map = fdp->fd_map; 146 NDSLOTTYPE mask; 147 int off, minoff; 148 149 if (low >= size) 150 return (-1); 151 152 off = NDSLOT(size); 153 if (size % NDENTRIES) { 154 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 155 if ((mask &= map[off]) != 0) 156 return (off * NDENTRIES + flsl(mask) - 1); 157 --off; 158 } 159 for (minoff = NDSLOT(low); off >= minoff; --off) 160 if (map[off] != 0) 161 return (off * NDENTRIES + flsl(map[off]) - 1); 162 return (size - 1); 163 } 164 165 static int 166 fdisused(struct filedesc *fdp, int fd) 167 { 168 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 169 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 170 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 171 } 172 173 /* 174 * Mark a file descriptor as used. 175 */ 176 void 177 fdused(struct filedesc *fdp, int fd) 178 { 179 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 180 KASSERT(!fdisused(fdp, fd), 181 ("fd already used")); 182 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 183 if (fd > fdp->fd_lastfile) 184 fdp->fd_lastfile = fd; 185 if (fd == fdp->fd_freefile) 186 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 187 } 188 189 /* 190 * Mark a file descriptor as unused. 191 */ 192 void 193 fdunused(struct filedesc *fdp, int fd) 194 { 195 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 196 KASSERT(fdisused(fdp, fd), 197 ("fd is already unused")); 198 KASSERT(fdp->fd_ofiles[fd] == NULL, 199 ("fd is still in use")); 200 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 201 if (fd < fdp->fd_freefile) 202 fdp->fd_freefile = fd; 203 if (fd == fdp->fd_lastfile) 204 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 205 } 206 207 /* 208 * System calls on descriptors. 209 */ 210 #ifndef _SYS_SYSPROTO_H_ 211 struct getdtablesize_args { 212 int dummy; 213 }; 214 #endif 215 /* 216 * MPSAFE 217 */ 218 /* ARGSUSED */ 219 int 220 getdtablesize(td, uap) 221 struct thread *td; 222 struct getdtablesize_args *uap; 223 { 224 struct proc *p = td->td_proc; 225 226 PROC_LOCK(p); 227 td->td_retval[0] = 228 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 229 PROC_UNLOCK(p); 230 return (0); 231 } 232 233 /* 234 * Duplicate a file descriptor to a particular value. 235 * 236 * note: keep in mind that a potential race condition exists when closing 237 * descriptors from a shared descriptor table (via rfork). 238 */ 239 #ifndef _SYS_SYSPROTO_H_ 240 struct dup2_args { 241 u_int from; 242 u_int to; 243 }; 244 #endif 245 /* 246 * MPSAFE 247 */ 248 /* ARGSUSED */ 249 int 250 dup2(td, uap) 251 struct thread *td; 252 struct dup2_args *uap; 253 { 254 255 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 256 td->td_retval)); 257 } 258 259 /* 260 * Duplicate a file descriptor. 261 */ 262 #ifndef _SYS_SYSPROTO_H_ 263 struct dup_args { 264 u_int fd; 265 }; 266 #endif 267 /* 268 * MPSAFE 269 */ 270 /* ARGSUSED */ 271 int 272 dup(td, uap) 273 struct thread *td; 274 struct dup_args *uap; 275 { 276 277 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 278 } 279 280 /* 281 * The file control system call. 282 */ 283 #ifndef _SYS_SYSPROTO_H_ 284 struct fcntl_args { 285 int fd; 286 int cmd; 287 long arg; 288 }; 289 #endif 290 /* 291 * MPSAFE 292 */ 293 /* ARGSUSED */ 294 int 295 fcntl(td, uap) 296 struct thread *td; 297 struct fcntl_args *uap; 298 { 299 struct flock fl; 300 intptr_t arg; 301 int error; 302 303 error = 0; 304 switch (uap->cmd) { 305 case F_GETLK: 306 case F_SETLK: 307 case F_SETLKW: 308 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 309 arg = (intptr_t)&fl; 310 break; 311 default: 312 arg = uap->arg; 313 break; 314 } 315 if (error) 316 return (error); 317 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 318 if (error) 319 return (error); 320 if (uap->cmd == F_GETLK) 321 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 322 return (error); 323 } 324 325 int 326 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 327 { 328 struct filedesc *fdp; 329 struct flock *flp; 330 struct file *fp; 331 struct proc *p; 332 char *pop; 333 struct vnode *vp; 334 u_int newmin; 335 int error, flg, tmp; 336 337 error = 0; 338 flg = F_POSIX; 339 p = td->td_proc; 340 fdp = p->p_fd; 341 mtx_lock(&Giant); 342 FILEDESC_LOCK(fdp); 343 if ((unsigned)fd >= fdp->fd_nfiles || 344 (fp = fdp->fd_ofiles[fd]) == NULL) { 345 FILEDESC_UNLOCK(fdp); 346 error = EBADF; 347 goto done2; 348 } 349 pop = &fdp->fd_ofileflags[fd]; 350 351 switch (cmd) { 352 case F_DUPFD: 353 FILEDESC_UNLOCK(fdp); 354 newmin = arg; 355 PROC_LOCK(p); 356 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 357 newmin >= maxfilesperproc) { 358 PROC_UNLOCK(p); 359 error = EINVAL; 360 break; 361 } 362 PROC_UNLOCK(p); 363 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 364 break; 365 366 case F_GETFD: 367 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 368 FILEDESC_UNLOCK(fdp); 369 break; 370 371 case F_SETFD: 372 *pop = (*pop &~ UF_EXCLOSE) | 373 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 374 FILEDESC_UNLOCK(fdp); 375 break; 376 377 case F_GETFL: 378 FILE_LOCK(fp); 379 FILEDESC_UNLOCK(fdp); 380 td->td_retval[0] = OFLAGS(fp->f_flag); 381 FILE_UNLOCK(fp); 382 break; 383 384 case F_SETFL: 385 FILE_LOCK(fp); 386 FILEDESC_UNLOCK(fdp); 387 fhold_locked(fp); 388 fp->f_flag &= ~FCNTLFLAGS; 389 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 390 FILE_UNLOCK(fp); 391 tmp = fp->f_flag & FNONBLOCK; 392 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 393 if (error) { 394 fdrop(fp, td); 395 break; 396 } 397 tmp = fp->f_flag & FASYNC; 398 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 399 if (error == 0) { 400 fdrop(fp, td); 401 break; 402 } 403 FILE_LOCK(fp); 404 fp->f_flag &= ~FNONBLOCK; 405 FILE_UNLOCK(fp); 406 tmp = 0; 407 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 408 fdrop(fp, td); 409 break; 410 411 case F_GETOWN: 412 fhold(fp); 413 FILEDESC_UNLOCK(fdp); 414 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 415 if (error == 0) 416 td->td_retval[0] = tmp; 417 fdrop(fp, td); 418 break; 419 420 case F_SETOWN: 421 fhold(fp); 422 FILEDESC_UNLOCK(fdp); 423 tmp = arg; 424 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 425 fdrop(fp, td); 426 break; 427 428 case F_SETLKW: 429 flg |= F_WAIT; 430 /* FALLTHROUGH F_SETLK */ 431 432 case F_SETLK: 433 if (fp->f_type != DTYPE_VNODE) { 434 FILEDESC_UNLOCK(fdp); 435 error = EBADF; 436 break; 437 } 438 439 flp = (struct flock *)arg; 440 if (flp->l_whence == SEEK_CUR) { 441 if (fp->f_offset < 0 || 442 (flp->l_start > 0 && 443 fp->f_offset > OFF_MAX - flp->l_start)) { 444 FILEDESC_UNLOCK(fdp); 445 error = EOVERFLOW; 446 break; 447 } 448 flp->l_start += fp->f_offset; 449 } 450 451 /* 452 * VOP_ADVLOCK() may block. 453 */ 454 fhold(fp); 455 FILEDESC_UNLOCK(fdp); 456 vp = fp->f_vnode; 457 458 switch (flp->l_type) { 459 case F_RDLCK: 460 if ((fp->f_flag & FREAD) == 0) { 461 error = EBADF; 462 break; 463 } 464 PROC_LOCK(p->p_leader); 465 p->p_leader->p_flag |= P_ADVLOCK; 466 PROC_UNLOCK(p->p_leader); 467 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 468 flp, flg); 469 break; 470 case F_WRLCK: 471 if ((fp->f_flag & FWRITE) == 0) { 472 error = EBADF; 473 break; 474 } 475 PROC_LOCK(p->p_leader); 476 p->p_leader->p_flag |= P_ADVLOCK; 477 PROC_UNLOCK(p->p_leader); 478 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 479 flp, flg); 480 break; 481 case F_UNLCK: 482 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 483 flp, F_POSIX); 484 break; 485 default: 486 error = EINVAL; 487 break; 488 } 489 /* Check for race with close */ 490 FILEDESC_LOCK(fdp); 491 if ((unsigned) fd >= fdp->fd_nfiles || 492 fp != fdp->fd_ofiles[fd]) { 493 FILEDESC_UNLOCK(fdp); 494 flp->l_whence = SEEK_SET; 495 flp->l_start = 0; 496 flp->l_len = 0; 497 flp->l_type = F_UNLCK; 498 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 499 F_UNLCK, flp, F_POSIX); 500 } else 501 FILEDESC_UNLOCK(fdp); 502 fdrop(fp, td); 503 break; 504 505 case F_GETLK: 506 if (fp->f_type != DTYPE_VNODE) { 507 FILEDESC_UNLOCK(fdp); 508 error = EBADF; 509 break; 510 } 511 flp = (struct flock *)arg; 512 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 513 flp->l_type != F_UNLCK) { 514 FILEDESC_UNLOCK(fdp); 515 error = EINVAL; 516 break; 517 } 518 if (flp->l_whence == SEEK_CUR) { 519 if ((flp->l_start > 0 && 520 fp->f_offset > OFF_MAX - flp->l_start) || 521 (flp->l_start < 0 && 522 fp->f_offset < OFF_MIN - flp->l_start)) { 523 FILEDESC_UNLOCK(fdp); 524 error = EOVERFLOW; 525 break; 526 } 527 flp->l_start += fp->f_offset; 528 } 529 /* 530 * VOP_ADVLOCK() may block. 531 */ 532 fhold(fp); 533 FILEDESC_UNLOCK(fdp); 534 vp = fp->f_vnode; 535 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 536 F_POSIX); 537 fdrop(fp, td); 538 break; 539 default: 540 FILEDESC_UNLOCK(fdp); 541 error = EINVAL; 542 break; 543 } 544 done2: 545 mtx_unlock(&Giant); 546 return (error); 547 } 548 549 /* 550 * Common code for dup, dup2, and fcntl(F_DUPFD). 551 */ 552 static int 553 do_dup(td, type, old, new, retval) 554 enum dup_type type; 555 int old, new; 556 register_t *retval; 557 struct thread *td; 558 { 559 struct filedesc *fdp; 560 struct proc *p; 561 struct file *fp; 562 struct file *delfp; 563 int error, holdleaders, maxfd; 564 565 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 566 ("invalid dup type %d", type)); 567 568 p = td->td_proc; 569 fdp = p->p_fd; 570 571 /* 572 * Verify we have a valid descriptor to dup from and possibly to 573 * dup to. 574 */ 575 if (old < 0 || new < 0) 576 return (EBADF); 577 PROC_LOCK(p); 578 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 579 PROC_UNLOCK(p); 580 if (new >= maxfd) 581 return (EMFILE); 582 583 FILEDESC_LOCK(fdp); 584 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 585 FILEDESC_UNLOCK(fdp); 586 return (EBADF); 587 } 588 if (type == DUP_FIXED && old == new) { 589 *retval = new; 590 FILEDESC_UNLOCK(fdp); 591 return (0); 592 } 593 fp = fdp->fd_ofiles[old]; 594 fhold(fp); 595 596 /* 597 * If the caller specified a file descriptor, make sure the file 598 * table is large enough to hold it, and grab it. Otherwise, just 599 * allocate a new descriptor the usual way. Since the filedesc 600 * lock may be temporarily dropped in the process, we have to look 601 * out for a race. 602 */ 603 if (type == DUP_FIXED) { 604 if (new >= fdp->fd_nfiles) 605 fdgrowtable(fdp, new + 1); 606 if (fdp->fd_ofiles[new] == NULL) 607 fdused(fdp, new); 608 } else { 609 if ((error = fdalloc(td, new, &new)) != 0) { 610 FILEDESC_UNLOCK(fdp); 611 fdrop(fp, td); 612 return (error); 613 } 614 } 615 616 /* 617 * If the old file changed out from under us then treat it as a 618 * bad file descriptor. Userland should do its own locking to 619 * avoid this case. 620 */ 621 if (fdp->fd_ofiles[old] != fp) { 622 /* we've allocated a descriptor which we won't use */ 623 if (fdp->fd_ofiles[new] == NULL) 624 fdunused(fdp, new); 625 FILEDESC_UNLOCK(fdp); 626 fdrop(fp, td); 627 return (EBADF); 628 } 629 KASSERT(old != new, 630 ("new fd is same as old")); 631 632 /* 633 * Save info on the descriptor being overwritten. We cannot close 634 * it without introducing an ownership race for the slot, since we 635 * need to drop the filedesc lock to call closef(). 636 * 637 * XXX this duplicates parts of close(). 638 */ 639 delfp = fdp->fd_ofiles[new]; 640 holdleaders = 0; 641 if (delfp != NULL) { 642 if (td->td_proc->p_fdtol != NULL) { 643 /* 644 * Ask fdfree() to sleep to ensure that all relevant 645 * process leaders can be traversed in closef(). 646 */ 647 fdp->fd_holdleaderscount++; 648 holdleaders = 1; 649 } 650 } 651 652 /* 653 * Duplicate the source descriptor 654 */ 655 fdp->fd_ofiles[new] = fp; 656 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 657 if (new > fdp->fd_lastfile) 658 fdp->fd_lastfile = new; 659 FILEDESC_UNLOCK(fdp); 660 *retval = new; 661 662 /* 663 * If we dup'd over a valid file, we now own the reference to it 664 * and must dispose of it using closef() semantics (as if a 665 * close() were performed on it). 666 * 667 * XXX this duplicates parts of close(). 668 */ 669 if (delfp != NULL) { 670 /* XXX need to call knote_fdclose() */ 671 mtx_lock(&Giant); 672 (void) closef(delfp, td); 673 mtx_unlock(&Giant); 674 if (holdleaders) { 675 FILEDESC_LOCK(fdp); 676 fdp->fd_holdleaderscount--; 677 if (fdp->fd_holdleaderscount == 0 && 678 fdp->fd_holdleaderswakeup != 0) { 679 fdp->fd_holdleaderswakeup = 0; 680 wakeup(&fdp->fd_holdleaderscount); 681 } 682 FILEDESC_UNLOCK(fdp); 683 } 684 } 685 return (0); 686 } 687 688 /* 689 * If sigio is on the list associated with a process or process group, 690 * disable signalling from the device, remove sigio from the list and 691 * free sigio. 692 */ 693 void 694 funsetown(sigiop) 695 struct sigio **sigiop; 696 { 697 struct sigio *sigio; 698 699 SIGIO_LOCK(); 700 sigio = *sigiop; 701 if (sigio == NULL) { 702 SIGIO_UNLOCK(); 703 return; 704 } 705 *(sigio->sio_myref) = NULL; 706 if ((sigio)->sio_pgid < 0) { 707 struct pgrp *pg = (sigio)->sio_pgrp; 708 PGRP_LOCK(pg); 709 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 710 sigio, sio_pgsigio); 711 PGRP_UNLOCK(pg); 712 } else { 713 struct proc *p = (sigio)->sio_proc; 714 PROC_LOCK(p); 715 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 716 sigio, sio_pgsigio); 717 PROC_UNLOCK(p); 718 } 719 SIGIO_UNLOCK(); 720 crfree(sigio->sio_ucred); 721 FREE(sigio, M_SIGIO); 722 } 723 724 /* 725 * Free a list of sigio structures. 726 * We only need to lock the SIGIO_LOCK because we have made ourselves 727 * inaccessable to callers of fsetown and therefore do not need to lock 728 * the proc or pgrp struct for the list manipulation. 729 */ 730 void 731 funsetownlst(sigiolst) 732 struct sigiolst *sigiolst; 733 { 734 struct proc *p; 735 struct pgrp *pg; 736 struct sigio *sigio; 737 738 sigio = SLIST_FIRST(sigiolst); 739 if (sigio == NULL) 740 return; 741 p = NULL; 742 pg = NULL; 743 744 /* 745 * Every entry of the list should belong 746 * to a single proc or pgrp. 747 */ 748 if (sigio->sio_pgid < 0) { 749 pg = sigio->sio_pgrp; 750 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 751 } else /* if (sigio->sio_pgid > 0) */ { 752 p = sigio->sio_proc; 753 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 754 } 755 756 SIGIO_LOCK(); 757 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 758 *(sigio->sio_myref) = NULL; 759 if (pg != NULL) { 760 KASSERT(sigio->sio_pgid < 0, 761 ("Proc sigio in pgrp sigio list")); 762 KASSERT(sigio->sio_pgrp == pg, 763 ("Bogus pgrp in sigio list")); 764 PGRP_LOCK(pg); 765 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 766 sio_pgsigio); 767 PGRP_UNLOCK(pg); 768 } else /* if (p != NULL) */ { 769 KASSERT(sigio->sio_pgid > 0, 770 ("Pgrp sigio in proc sigio list")); 771 KASSERT(sigio->sio_proc == p, 772 ("Bogus proc in sigio list")); 773 PROC_LOCK(p); 774 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 775 sio_pgsigio); 776 PROC_UNLOCK(p); 777 } 778 SIGIO_UNLOCK(); 779 crfree(sigio->sio_ucred); 780 FREE(sigio, M_SIGIO); 781 SIGIO_LOCK(); 782 } 783 SIGIO_UNLOCK(); 784 } 785 786 /* 787 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 788 * 789 * After permission checking, add a sigio structure to the sigio list for 790 * the process or process group. 791 */ 792 int 793 fsetown(pgid, sigiop) 794 pid_t pgid; 795 struct sigio **sigiop; 796 { 797 struct proc *proc; 798 struct pgrp *pgrp; 799 struct sigio *sigio; 800 int ret; 801 802 if (pgid == 0) { 803 funsetown(sigiop); 804 return (0); 805 } 806 807 ret = 0; 808 809 /* Allocate and fill in the new sigio out of locks. */ 810 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 811 sigio->sio_pgid = pgid; 812 sigio->sio_ucred = crhold(curthread->td_ucred); 813 sigio->sio_myref = sigiop; 814 815 sx_slock(&proctree_lock); 816 if (pgid > 0) { 817 proc = pfind(pgid); 818 if (proc == NULL) { 819 ret = ESRCH; 820 goto fail; 821 } 822 823 /* 824 * Policy - Don't allow a process to FSETOWN a process 825 * in another session. 826 * 827 * Remove this test to allow maximum flexibility or 828 * restrict FSETOWN to the current process or process 829 * group for maximum safety. 830 */ 831 PROC_UNLOCK(proc); 832 if (proc->p_session != curthread->td_proc->p_session) { 833 ret = EPERM; 834 goto fail; 835 } 836 837 pgrp = NULL; 838 } else /* if (pgid < 0) */ { 839 pgrp = pgfind(-pgid); 840 if (pgrp == NULL) { 841 ret = ESRCH; 842 goto fail; 843 } 844 PGRP_UNLOCK(pgrp); 845 846 /* 847 * Policy - Don't allow a process to FSETOWN a process 848 * in another session. 849 * 850 * Remove this test to allow maximum flexibility or 851 * restrict FSETOWN to the current process or process 852 * group for maximum safety. 853 */ 854 if (pgrp->pg_session != curthread->td_proc->p_session) { 855 ret = EPERM; 856 goto fail; 857 } 858 859 proc = NULL; 860 } 861 funsetown(sigiop); 862 if (pgid > 0) { 863 PROC_LOCK(proc); 864 /* 865 * Since funsetownlst() is called without the proctree 866 * locked, we need to check for P_WEXIT. 867 * XXX: is ESRCH correct? 868 */ 869 if ((proc->p_flag & P_WEXIT) != 0) { 870 PROC_UNLOCK(proc); 871 ret = ESRCH; 872 goto fail; 873 } 874 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 875 sigio->sio_proc = proc; 876 PROC_UNLOCK(proc); 877 } else { 878 PGRP_LOCK(pgrp); 879 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 880 sigio->sio_pgrp = pgrp; 881 PGRP_UNLOCK(pgrp); 882 } 883 sx_sunlock(&proctree_lock); 884 SIGIO_LOCK(); 885 *sigiop = sigio; 886 SIGIO_UNLOCK(); 887 return (0); 888 889 fail: 890 sx_sunlock(&proctree_lock); 891 crfree(sigio->sio_ucred); 892 FREE(sigio, M_SIGIO); 893 return (ret); 894 } 895 896 /* 897 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 898 */ 899 pid_t 900 fgetown(sigiop) 901 struct sigio **sigiop; 902 { 903 pid_t pgid; 904 905 SIGIO_LOCK(); 906 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 907 SIGIO_UNLOCK(); 908 return (pgid); 909 } 910 911 /* 912 * Close a file descriptor. 913 */ 914 #ifndef _SYS_SYSPROTO_H_ 915 struct close_args { 916 int fd; 917 }; 918 #endif 919 /* 920 * MPSAFE 921 */ 922 /* ARGSUSED */ 923 int 924 close(td, uap) 925 struct thread *td; 926 struct close_args *uap; 927 { 928 struct filedesc *fdp; 929 struct file *fp; 930 int fd, error; 931 int holdleaders; 932 933 fd = uap->fd; 934 error = 0; 935 holdleaders = 0; 936 fdp = td->td_proc->p_fd; 937 mtx_lock(&Giant); 938 FILEDESC_LOCK(fdp); 939 if ((unsigned)fd >= fdp->fd_nfiles || 940 (fp = fdp->fd_ofiles[fd]) == NULL) { 941 FILEDESC_UNLOCK(fdp); 942 mtx_unlock(&Giant); 943 return (EBADF); 944 } 945 fdp->fd_ofiles[fd] = NULL; 946 fdp->fd_ofileflags[fd] = 0; 947 fdunused(fdp, fd); 948 if (td->td_proc->p_fdtol != NULL) { 949 /* 950 * Ask fdfree() to sleep to ensure that all relevant 951 * process leaders can be traversed in closef(). 952 */ 953 fdp->fd_holdleaderscount++; 954 holdleaders = 1; 955 } 956 957 /* 958 * we now hold the fp reference that used to be owned by the descriptor 959 * array. 960 */ 961 if (fd < fdp->fd_knlistsize) { 962 FILEDESC_UNLOCK(fdp); 963 knote_fdclose(td, fd); 964 } else 965 FILEDESC_UNLOCK(fdp); 966 967 error = closef(fp, td); 968 mtx_unlock(&Giant); 969 if (holdleaders) { 970 FILEDESC_LOCK(fdp); 971 fdp->fd_holdleaderscount--; 972 if (fdp->fd_holdleaderscount == 0 && 973 fdp->fd_holdleaderswakeup != 0) { 974 fdp->fd_holdleaderswakeup = 0; 975 wakeup(&fdp->fd_holdleaderscount); 976 } 977 FILEDESC_UNLOCK(fdp); 978 } 979 return (error); 980 } 981 982 #if defined(COMPAT_43) 983 /* 984 * Return status information about a file descriptor. 985 */ 986 #ifndef _SYS_SYSPROTO_H_ 987 struct ofstat_args { 988 int fd; 989 struct ostat *sb; 990 }; 991 #endif 992 /* 993 * MPSAFE 994 */ 995 /* ARGSUSED */ 996 int 997 ofstat(td, uap) 998 struct thread *td; 999 struct ofstat_args *uap; 1000 { 1001 struct file *fp; 1002 struct stat ub; 1003 struct ostat oub; 1004 int error; 1005 1006 if ((error = fget(td, uap->fd, &fp)) != 0) 1007 goto done2; 1008 error = fo_stat(fp, &ub, td->td_ucred, td); 1009 if (error == 0) { 1010 cvtstat(&ub, &oub); 1011 error = copyout(&oub, uap->sb, sizeof(oub)); 1012 } 1013 fdrop(fp, td); 1014 done2: 1015 return (error); 1016 } 1017 #endif /* COMPAT_43 */ 1018 1019 /* 1020 * Return status information about a file descriptor. 1021 */ 1022 #ifndef _SYS_SYSPROTO_H_ 1023 struct fstat_args { 1024 int fd; 1025 struct stat *sb; 1026 }; 1027 #endif 1028 /* 1029 * MPSAFE 1030 */ 1031 /* ARGSUSED */ 1032 int 1033 fstat(td, uap) 1034 struct thread *td; 1035 struct fstat_args *uap; 1036 { 1037 struct file *fp; 1038 struct stat ub; 1039 int error; 1040 1041 if ((error = fget(td, uap->fd, &fp)) != 0) 1042 goto done2; 1043 error = fo_stat(fp, &ub, td->td_ucred, td); 1044 if (error == 0) 1045 error = copyout(&ub, uap->sb, sizeof(ub)); 1046 fdrop(fp, td); 1047 done2: 1048 return (error); 1049 } 1050 1051 /* 1052 * Return status information about a file descriptor. 1053 */ 1054 #ifndef _SYS_SYSPROTO_H_ 1055 struct nfstat_args { 1056 int fd; 1057 struct nstat *sb; 1058 }; 1059 #endif 1060 /* 1061 * MPSAFE 1062 */ 1063 /* ARGSUSED */ 1064 int 1065 nfstat(td, uap) 1066 struct thread *td; 1067 struct nfstat_args *uap; 1068 { 1069 struct file *fp; 1070 struct stat ub; 1071 struct nstat nub; 1072 int error; 1073 1074 if ((error = fget(td, uap->fd, &fp)) != 0) 1075 goto done2; 1076 error = fo_stat(fp, &ub, td->td_ucred, td); 1077 if (error == 0) { 1078 cvtnstat(&ub, &nub); 1079 error = copyout(&nub, uap->sb, sizeof(nub)); 1080 } 1081 fdrop(fp, td); 1082 done2: 1083 return (error); 1084 } 1085 1086 /* 1087 * Return pathconf information about a file descriptor. 1088 */ 1089 #ifndef _SYS_SYSPROTO_H_ 1090 struct fpathconf_args { 1091 int fd; 1092 int name; 1093 }; 1094 #endif 1095 /* 1096 * MPSAFE 1097 */ 1098 /* ARGSUSED */ 1099 int 1100 fpathconf(td, uap) 1101 struct thread *td; 1102 struct fpathconf_args *uap; 1103 { 1104 struct file *fp; 1105 struct vnode *vp; 1106 int error; 1107 1108 if ((error = fget(td, uap->fd, &fp)) != 0) 1109 return (error); 1110 1111 /* If asynchronous I/O is available, it works for all descriptors. */ 1112 if (uap->name == _PC_ASYNC_IO) { 1113 td->td_retval[0] = async_io_version; 1114 goto out; 1115 } 1116 vp = fp->f_vnode; 1117 if (vp != NULL) { 1118 mtx_lock(&Giant); 1119 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1120 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1121 VOP_UNLOCK(vp, 0, td); 1122 mtx_unlock(&Giant); 1123 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1124 if (uap->name != _PC_PIPE_BUF) { 1125 error = EINVAL; 1126 } else { 1127 td->td_retval[0] = PIPE_BUF; 1128 error = 0; 1129 } 1130 } else { 1131 error = EOPNOTSUPP; 1132 } 1133 out: 1134 fdrop(fp, td); 1135 return (error); 1136 } 1137 1138 /* 1139 * Grow the file table to accomodate (at least) nfd descriptors. This may 1140 * block and drop the filedesc lock, but it will reacquire it before 1141 * returing. 1142 */ 1143 static void 1144 fdgrowtable(struct filedesc *fdp, int nfd) 1145 { 1146 struct file **ntable; 1147 char *nfileflags; 1148 int nnfiles, onfiles; 1149 NDSLOTTYPE *nmap; 1150 1151 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1152 1153 KASSERT(fdp->fd_nfiles > 0, 1154 ("zero-length file table")); 1155 1156 /* compute the size of the new table */ 1157 onfiles = fdp->fd_nfiles; 1158 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1159 if (nnfiles <= onfiles) 1160 /* the table is already large enough */ 1161 return; 1162 1163 /* allocate a new table and (if required) new bitmaps */ 1164 FILEDESC_UNLOCK(fdp); 1165 MALLOC(ntable, struct file **, nnfiles * OFILESIZE, 1166 M_FILEDESC, M_ZERO | M_WAITOK); 1167 nfileflags = (char *)&ntable[nnfiles]; 1168 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1169 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE, 1170 M_FILEDESC, M_ZERO | M_WAITOK); 1171 else 1172 nmap = NULL; 1173 FILEDESC_LOCK(fdp); 1174 1175 /* 1176 * We now have new tables ready to go. Since we dropped the 1177 * filedesc lock to call malloc(), watch out for a race. 1178 */ 1179 onfiles = fdp->fd_nfiles; 1180 if (onfiles >= nnfiles) { 1181 /* we lost the race, but that's OK */ 1182 free(ntable, M_FILEDESC); 1183 if (nmap != NULL) 1184 free(nmap, M_FILEDESC); 1185 return; 1186 } 1187 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1188 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1189 if (onfiles > NDFILE) 1190 free(fdp->fd_ofiles, M_FILEDESC); 1191 fdp->fd_ofiles = ntable; 1192 fdp->fd_ofileflags = nfileflags; 1193 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1194 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1195 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1196 free(fdp->fd_map, M_FILEDESC); 1197 fdp->fd_map = nmap; 1198 } 1199 fdp->fd_nfiles = nnfiles; 1200 } 1201 1202 /* 1203 * Allocate a file descriptor for the process. 1204 */ 1205 int 1206 fdalloc(struct thread *td, int minfd, int *result) 1207 { 1208 struct proc *p = td->td_proc; 1209 struct filedesc *fdp = p->p_fd; 1210 int fd = -1, maxfd; 1211 1212 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1213 1214 PROC_LOCK(p); 1215 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1216 PROC_UNLOCK(p); 1217 1218 /* 1219 * Search the bitmap for a free descriptor. If none is found, try 1220 * to grow the file table. Keep at it until we either get a file 1221 * descriptor or run into process or system limits; fdgrowtable() 1222 * may drop the filedesc lock, so we're in a race. 1223 */ 1224 for (;;) { 1225 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1226 if (fd >= maxfd) 1227 return (EMFILE); 1228 if (fd < fdp->fd_nfiles) 1229 break; 1230 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1231 } 1232 1233 /* 1234 * Perform some sanity checks, then mark the file descriptor as 1235 * used and return it to the caller. 1236 */ 1237 KASSERT(!fdisused(fdp, fd), 1238 ("fd_first_free() returned non-free descriptor")); 1239 KASSERT(fdp->fd_ofiles[fd] == NULL, 1240 ("free descriptor isn't")); 1241 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1242 fdused(fdp, fd); 1243 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 1244 *result = fd; 1245 return (0); 1246 } 1247 1248 /* 1249 * Check to see whether n user file descriptors 1250 * are available to the process p. 1251 */ 1252 int 1253 fdavail(td, n) 1254 struct thread *td; 1255 int n; 1256 { 1257 struct proc *p = td->td_proc; 1258 struct filedesc *fdp = td->td_proc->p_fd; 1259 struct file **fpp; 1260 int i, lim, last; 1261 1262 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1263 1264 PROC_LOCK(p); 1265 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1266 PROC_UNLOCK(p); 1267 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1268 return (1); 1269 last = min(fdp->fd_nfiles, lim); 1270 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1271 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1272 if (*fpp == NULL && --n <= 0) 1273 return (1); 1274 } 1275 return (0); 1276 } 1277 1278 /* 1279 * Create a new open file structure and allocate 1280 * a file decriptor for the process that refers to it. 1281 * We add one reference to the file for the descriptor table 1282 * and one reference for resultfp. This is to prevent us being 1283 * prempted and the entry in the descriptor table closed after 1284 * we release the FILEDESC lock. 1285 */ 1286 int 1287 falloc(td, resultfp, resultfd) 1288 struct thread *td; 1289 struct file **resultfp; 1290 int *resultfd; 1291 { 1292 struct proc *p = td->td_proc; 1293 struct file *fp, *fq; 1294 int error, i; 1295 int maxuserfiles = maxfiles - (maxfiles / 20); 1296 static struct timeval lastfail; 1297 static int curfail; 1298 1299 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1300 sx_xlock(&filelist_lock); 1301 if ((nfiles >= maxuserfiles && (td->td_ucred->cr_ruid != 0 || 1302 jailed(td->td_ucred))) || nfiles >= maxfiles) { 1303 if (ppsratecheck(&lastfail, &curfail, 1)) { 1304 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1305 td->td_ucred->cr_ruid); 1306 } 1307 sx_xunlock(&filelist_lock); 1308 uma_zfree(file_zone, fp); 1309 return (ENFILE); 1310 } 1311 nfiles++; 1312 1313 /* 1314 * If the process has file descriptor zero open, add the new file 1315 * descriptor to the list of open files at that point, otherwise 1316 * put it at the front of the list of open files. 1317 */ 1318 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1319 fp->f_count = 1; 1320 if (resultfp) 1321 fp->f_count++; 1322 fp->f_cred = crhold(td->td_ucred); 1323 fp->f_ops = &badfileops; 1324 fp->f_data = NULL; 1325 fp->f_vnode = NULL; 1326 FILEDESC_LOCK(p->p_fd); 1327 if ((fq = p->p_fd->fd_ofiles[0])) { 1328 LIST_INSERT_AFTER(fq, fp, f_list); 1329 } else { 1330 LIST_INSERT_HEAD(&filehead, fp, f_list); 1331 } 1332 sx_xunlock(&filelist_lock); 1333 if ((error = fdalloc(td, 0, &i))) { 1334 FILEDESC_UNLOCK(p->p_fd); 1335 fdrop(fp, td); 1336 if (resultfp) 1337 fdrop(fp, td); 1338 return (error); 1339 } 1340 p->p_fd->fd_ofiles[i] = fp; 1341 FILEDESC_UNLOCK(p->p_fd); 1342 if (resultfp) 1343 *resultfp = fp; 1344 if (resultfd) 1345 *resultfd = i; 1346 return (0); 1347 } 1348 1349 /* 1350 * Free a file descriptor. 1351 */ 1352 void 1353 ffree(fp) 1354 struct file *fp; 1355 { 1356 1357 KASSERT(fp->f_count == 0, ("ffree: fp_fcount not 0!")); 1358 sx_xlock(&filelist_lock); 1359 LIST_REMOVE(fp, f_list); 1360 nfiles--; 1361 sx_xunlock(&filelist_lock); 1362 crfree(fp->f_cred); 1363 uma_zfree(file_zone, fp); 1364 } 1365 1366 /* 1367 * Build a new filedesc structure from another. 1368 * Copy the current, root, and jail root vnode references. 1369 */ 1370 struct filedesc * 1371 fdinit(fdp) 1372 struct filedesc *fdp; 1373 { 1374 struct filedesc0 *newfdp; 1375 1376 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1377 1378 FILEDESC_UNLOCK(fdp); 1379 MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0), 1380 M_FILEDESC, M_WAITOK | M_ZERO); 1381 FILEDESC_LOCK(fdp); 1382 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1383 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1384 if (newfdp->fd_fd.fd_cdir) 1385 VREF(newfdp->fd_fd.fd_cdir); 1386 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1387 if (newfdp->fd_fd.fd_rdir) 1388 VREF(newfdp->fd_fd.fd_rdir); 1389 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1390 if (newfdp->fd_fd.fd_jdir) 1391 VREF(newfdp->fd_fd.fd_jdir); 1392 1393 /* Create the file descriptor table. */ 1394 newfdp->fd_fd.fd_refcnt = 1; 1395 newfdp->fd_fd.fd_cmask = CMASK; 1396 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1397 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1398 newfdp->fd_fd.fd_nfiles = NDFILE; 1399 newfdp->fd_fd.fd_knlistsize = -1; 1400 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1401 return (&newfdp->fd_fd); 1402 } 1403 1404 /* 1405 * Share a filedesc structure. 1406 */ 1407 struct filedesc * 1408 fdshare(fdp) 1409 struct filedesc *fdp; 1410 { 1411 FILEDESC_LOCK(fdp); 1412 fdp->fd_refcnt++; 1413 FILEDESC_UNLOCK(fdp); 1414 return (fdp); 1415 } 1416 1417 /* 1418 * Copy a filedesc structure. 1419 * A NULL pointer in returns a NULL reference, this is to ease callers, 1420 * not catch errors. 1421 */ 1422 struct filedesc * 1423 fdcopy(fdp) 1424 struct filedesc *fdp; 1425 { 1426 struct filedesc *newfdp; 1427 int i; 1428 1429 /* Certain daemons might not have file descriptors. */ 1430 if (fdp == NULL) 1431 return (NULL); 1432 1433 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1434 newfdp = fdinit(fdp); 1435 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1436 FILEDESC_UNLOCK(fdp); 1437 FILEDESC_LOCK(newfdp); 1438 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1439 FILEDESC_UNLOCK(newfdp); 1440 FILEDESC_LOCK(fdp); 1441 } 1442 /* copy everything except kqueue descriptors */ 1443 newfdp->fd_freefile = -1; 1444 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1445 if (fdisused(fdp, i) && 1446 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) { 1447 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1448 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1449 fhold(newfdp->fd_ofiles[i]); 1450 newfdp->fd_lastfile = i; 1451 } else { 1452 if (newfdp->fd_freefile == -1) 1453 newfdp->fd_freefile = i; 1454 } 1455 } 1456 FILEDESC_UNLOCK(fdp); 1457 FILEDESC_LOCK(newfdp); 1458 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1459 if (newfdp->fd_ofiles[i] != NULL) 1460 fdused(newfdp, i); 1461 FILEDESC_UNLOCK(newfdp); 1462 FILEDESC_LOCK(fdp); 1463 if (newfdp->fd_freefile == -1) 1464 newfdp->fd_freefile = i; 1465 newfdp->fd_cmask = fdp->fd_cmask; 1466 return (newfdp); 1467 } 1468 1469 /* A mutex to protect the association between a proc and filedesc. */ 1470 struct mtx fdesc_mtx; 1471 MTX_SYSINIT(fdesc, &fdesc_mtx, "fdesc", MTX_DEF); 1472 1473 /* 1474 * Release a filedesc structure. 1475 */ 1476 void 1477 fdfree(td) 1478 struct thread *td; 1479 { 1480 struct filedesc *fdp; 1481 struct file **fpp; 1482 int i; 1483 struct filedesc_to_leader *fdtol; 1484 struct file *fp; 1485 struct vnode *vp; 1486 struct flock lf; 1487 1488 /* Certain daemons might not have file descriptors. */ 1489 fdp = td->td_proc->p_fd; 1490 if (fdp == NULL) 1491 return; 1492 1493 /* Check for special need to clear POSIX style locks */ 1494 fdtol = td->td_proc->p_fdtol; 1495 if (fdtol != NULL) { 1496 FILEDESC_LOCK(fdp); 1497 KASSERT(fdtol->fdl_refcount > 0, 1498 ("filedesc_to_refcount botch: fdl_refcount=%d", 1499 fdtol->fdl_refcount)); 1500 if (fdtol->fdl_refcount == 1 && 1501 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1502 i = 0; 1503 fpp = fdp->fd_ofiles; 1504 for (i = 0, fpp = fdp->fd_ofiles; 1505 i <= fdp->fd_lastfile; 1506 i++, fpp++) { 1507 if (*fpp == NULL || 1508 (*fpp)->f_type != DTYPE_VNODE) 1509 continue; 1510 fp = *fpp; 1511 fhold(fp); 1512 FILEDESC_UNLOCK(fdp); 1513 lf.l_whence = SEEK_SET; 1514 lf.l_start = 0; 1515 lf.l_len = 0; 1516 lf.l_type = F_UNLCK; 1517 vp = fp->f_vnode; 1518 (void) VOP_ADVLOCK(vp, 1519 (caddr_t)td->td_proc-> 1520 p_leader, 1521 F_UNLCK, 1522 &lf, 1523 F_POSIX); 1524 FILEDESC_LOCK(fdp); 1525 fdrop(fp, td); 1526 fpp = fdp->fd_ofiles + i; 1527 } 1528 } 1529 retry: 1530 if (fdtol->fdl_refcount == 1) { 1531 if (fdp->fd_holdleaderscount > 0 && 1532 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1533 /* 1534 * close() or do_dup() has cleared a reference 1535 * in a shared file descriptor table. 1536 */ 1537 fdp->fd_holdleaderswakeup = 1; 1538 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1539 PLOCK, "fdlhold", 0); 1540 goto retry; 1541 } 1542 if (fdtol->fdl_holdcount > 0) { 1543 /* 1544 * Ensure that fdtol->fdl_leader 1545 * remains valid in closef(). 1546 */ 1547 fdtol->fdl_wakeup = 1; 1548 msleep(fdtol, &fdp->fd_mtx, 1549 PLOCK, "fdlhold", 0); 1550 goto retry; 1551 } 1552 } 1553 fdtol->fdl_refcount--; 1554 if (fdtol->fdl_refcount == 0 && 1555 fdtol->fdl_holdcount == 0) { 1556 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1557 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1558 } else 1559 fdtol = NULL; 1560 td->td_proc->p_fdtol = NULL; 1561 FILEDESC_UNLOCK(fdp); 1562 if (fdtol != NULL) 1563 FREE(fdtol, M_FILEDESC_TO_LEADER); 1564 } 1565 FILEDESC_LOCK(fdp); 1566 if (--fdp->fd_refcnt > 0) { 1567 FILEDESC_UNLOCK(fdp); 1568 return; 1569 } 1570 1571 /* 1572 * We are the last reference to the structure, so we can 1573 * safely assume it will not change out from under us. 1574 */ 1575 FILEDESC_UNLOCK(fdp); 1576 fpp = fdp->fd_ofiles; 1577 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1578 if (*fpp) 1579 (void) closef(*fpp, td); 1580 } 1581 1582 /* XXX This should happen earlier. */ 1583 mtx_lock(&fdesc_mtx); 1584 td->td_proc->p_fd = NULL; 1585 mtx_unlock(&fdesc_mtx); 1586 1587 if (fdp->fd_nfiles > NDFILE) 1588 FREE(fdp->fd_ofiles, M_FILEDESC); 1589 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1590 FREE(fdp->fd_map, M_FILEDESC); 1591 if (fdp->fd_cdir) 1592 vrele(fdp->fd_cdir); 1593 if (fdp->fd_rdir) 1594 vrele(fdp->fd_rdir); 1595 if (fdp->fd_jdir) 1596 vrele(fdp->fd_jdir); 1597 if (fdp->fd_knlist) 1598 FREE(fdp->fd_knlist, M_KQUEUE); 1599 if (fdp->fd_knhash) 1600 FREE(fdp->fd_knhash, M_KQUEUE); 1601 mtx_destroy(&fdp->fd_mtx); 1602 FREE(fdp, M_FILEDESC); 1603 } 1604 1605 /* 1606 * For setugid programs, we don't want to people to use that setugidness 1607 * to generate error messages which write to a file which otherwise would 1608 * otherwise be off-limits to the process. We check for filesystems where 1609 * the vnode can change out from under us after execve (like [lin]procfs). 1610 * 1611 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1612 * sufficient. We also don't for check setugidness since we know we are. 1613 */ 1614 static int 1615 is_unsafe(struct file *fp) 1616 { 1617 if (fp->f_type == DTYPE_VNODE) { 1618 struct vnode *vp = fp->f_vnode; 1619 1620 if ((vp->v_vflag & VV_PROCDEP) != 0) 1621 return (1); 1622 } 1623 return (0); 1624 } 1625 1626 /* 1627 * Make this setguid thing safe, if at all possible. 1628 */ 1629 void 1630 setugidsafety(td) 1631 struct thread *td; 1632 { 1633 struct filedesc *fdp; 1634 int i; 1635 1636 /* Certain daemons might not have file descriptors. */ 1637 fdp = td->td_proc->p_fd; 1638 if (fdp == NULL) 1639 return; 1640 1641 /* 1642 * Note: fdp->fd_ofiles may be reallocated out from under us while 1643 * we are blocked in a close. Be careful! 1644 */ 1645 FILEDESC_LOCK(fdp); 1646 for (i = 0; i <= fdp->fd_lastfile; i++) { 1647 if (i > 2) 1648 break; 1649 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1650 struct file *fp; 1651 1652 if (i < fdp->fd_knlistsize) { 1653 FILEDESC_UNLOCK(fdp); 1654 knote_fdclose(td, i); 1655 FILEDESC_LOCK(fdp); 1656 } 1657 /* 1658 * NULL-out descriptor prior to close to avoid 1659 * a race while close blocks. 1660 */ 1661 fp = fdp->fd_ofiles[i]; 1662 fdp->fd_ofiles[i] = NULL; 1663 fdp->fd_ofileflags[i] = 0; 1664 fdunused(fdp, i); 1665 FILEDESC_UNLOCK(fdp); 1666 (void) closef(fp, td); 1667 FILEDESC_LOCK(fdp); 1668 } 1669 } 1670 FILEDESC_UNLOCK(fdp); 1671 } 1672 1673 /* 1674 * Close any files on exec? 1675 */ 1676 void 1677 fdcloseexec(td) 1678 struct thread *td; 1679 { 1680 struct filedesc *fdp; 1681 int i; 1682 1683 /* Certain daemons might not have file descriptors. */ 1684 fdp = td->td_proc->p_fd; 1685 if (fdp == NULL) 1686 return; 1687 1688 FILEDESC_LOCK(fdp); 1689 1690 /* 1691 * We cannot cache fd_ofiles or fd_ofileflags since operations 1692 * may block and rip them out from under us. 1693 */ 1694 for (i = 0; i <= fdp->fd_lastfile; i++) { 1695 if (fdp->fd_ofiles[i] != NULL && 1696 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1697 struct file *fp; 1698 1699 if (i < fdp->fd_knlistsize) { 1700 FILEDESC_UNLOCK(fdp); 1701 knote_fdclose(td, i); 1702 FILEDESC_LOCK(fdp); 1703 } 1704 /* 1705 * NULL-out descriptor prior to close to avoid 1706 * a race while close blocks. 1707 */ 1708 fp = fdp->fd_ofiles[i]; 1709 fdp->fd_ofiles[i] = NULL; 1710 fdp->fd_ofileflags[i] = 0; 1711 fdunused(fdp, i); 1712 FILEDESC_UNLOCK(fdp); 1713 (void) closef(fp, td); 1714 FILEDESC_LOCK(fdp); 1715 } 1716 } 1717 FILEDESC_UNLOCK(fdp); 1718 } 1719 1720 /* 1721 * It is unsafe for set[ug]id processes to be started with file 1722 * descriptors 0..2 closed, as these descriptors are given implicit 1723 * significance in the Standard C library. fdcheckstd() will create a 1724 * descriptor referencing /dev/null for each of stdin, stdout, and 1725 * stderr that is not already open. 1726 */ 1727 int 1728 fdcheckstd(td) 1729 struct thread *td; 1730 { 1731 struct nameidata nd; 1732 struct filedesc *fdp; 1733 struct file *fp; 1734 register_t retval; 1735 int fd, i, error, flags, devnull; 1736 1737 fdp = td->td_proc->p_fd; 1738 if (fdp == NULL) 1739 return (0); 1740 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1741 devnull = -1; 1742 error = 0; 1743 for (i = 0; i < 3; i++) { 1744 if (fdp->fd_ofiles[i] != NULL) 1745 continue; 1746 if (devnull < 0) { 1747 error = falloc(td, &fp, &fd); 1748 if (error != 0) 1749 break; 1750 /* Note extra ref on `fp' held for us by falloc(). */ 1751 KASSERT(fd == i, ("oof, we didn't get our fd")); 1752 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null", 1753 td); 1754 flags = FREAD | FWRITE; 1755 error = vn_open(&nd, &flags, 0, -1); 1756 if (error != 0) { 1757 /* 1758 * Someone may have closed the entry in the 1759 * file descriptor table, so check it hasn't 1760 * changed before dropping the reference count. 1761 */ 1762 FILEDESC_LOCK(fdp); 1763 KASSERT(fdp->fd_ofiles[fd] == fp, 1764 ("table not shared, how did it change?")); 1765 fdp->fd_ofiles[fd] = NULL; 1766 fdunused(fdp, fd); 1767 FILEDESC_UNLOCK(fdp); 1768 fdrop(fp, td); 1769 fdrop(fp, td); 1770 break; 1771 } 1772 NDFREE(&nd, NDF_ONLY_PNBUF); 1773 fp->f_vnode = nd.ni_vp; 1774 fp->f_data = nd.ni_vp; 1775 fp->f_flag = flags; 1776 fp->f_ops = &vnops; 1777 fp->f_type = DTYPE_VNODE; 1778 VOP_UNLOCK(nd.ni_vp, 0, td); 1779 devnull = fd; 1780 fdrop(fp, td); 1781 } else { 1782 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1783 if (error != 0) 1784 break; 1785 } 1786 } 1787 return (error); 1788 } 1789 1790 /* 1791 * Internal form of close. 1792 * Decrement reference count on file structure. 1793 * Note: td may be NULL when closing a file 1794 * that was being passed in a message. 1795 */ 1796 int 1797 closef(fp, td) 1798 struct file *fp; 1799 struct thread *td; 1800 { 1801 struct vnode *vp; 1802 struct flock lf; 1803 struct filedesc_to_leader *fdtol; 1804 struct filedesc *fdp; 1805 1806 if (fp == NULL) 1807 return (0); 1808 /* 1809 * POSIX record locking dictates that any close releases ALL 1810 * locks owned by this process. This is handled by setting 1811 * a flag in the unlock to free ONLY locks obeying POSIX 1812 * semantics, and not to free BSD-style file locks. 1813 * If the descriptor was in a message, POSIX-style locks 1814 * aren't passed with the descriptor. 1815 */ 1816 if (td != NULL && 1817 fp->f_type == DTYPE_VNODE) { 1818 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1819 lf.l_whence = SEEK_SET; 1820 lf.l_start = 0; 1821 lf.l_len = 0; 1822 lf.l_type = F_UNLCK; 1823 vp = fp->f_vnode; 1824 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1825 F_UNLCK, &lf, F_POSIX); 1826 } 1827 fdtol = td->td_proc->p_fdtol; 1828 if (fdtol != NULL) { 1829 /* 1830 * Handle special case where file descriptor table 1831 * is shared between multiple process leaders. 1832 */ 1833 fdp = td->td_proc->p_fd; 1834 FILEDESC_LOCK(fdp); 1835 for (fdtol = fdtol->fdl_next; 1836 fdtol != td->td_proc->p_fdtol; 1837 fdtol = fdtol->fdl_next) { 1838 if ((fdtol->fdl_leader->p_flag & 1839 P_ADVLOCK) == 0) 1840 continue; 1841 fdtol->fdl_holdcount++; 1842 FILEDESC_UNLOCK(fdp); 1843 lf.l_whence = SEEK_SET; 1844 lf.l_start = 0; 1845 lf.l_len = 0; 1846 lf.l_type = F_UNLCK; 1847 vp = fp->f_vnode; 1848 (void) VOP_ADVLOCK(vp, 1849 (caddr_t)fdtol->fdl_leader, 1850 F_UNLCK, &lf, F_POSIX); 1851 FILEDESC_LOCK(fdp); 1852 fdtol->fdl_holdcount--; 1853 if (fdtol->fdl_holdcount == 0 && 1854 fdtol->fdl_wakeup != 0) { 1855 fdtol->fdl_wakeup = 0; 1856 wakeup(fdtol); 1857 } 1858 } 1859 FILEDESC_UNLOCK(fdp); 1860 } 1861 } 1862 return (fdrop(fp, td)); 1863 } 1864 1865 /* 1866 * Drop reference on struct file passed in, may call closef if the 1867 * reference hits zero. 1868 */ 1869 int 1870 fdrop(fp, td) 1871 struct file *fp; 1872 struct thread *td; 1873 { 1874 1875 FILE_LOCK(fp); 1876 return (fdrop_locked(fp, td)); 1877 } 1878 1879 /* 1880 * Extract the file pointer associated with the specified descriptor for 1881 * the current user process. 1882 * 1883 * If the descriptor doesn't exist, EBADF is returned. 1884 * 1885 * If the descriptor exists but doesn't match 'flags' then 1886 * return EBADF for read attempts and EINVAL for write attempts. 1887 * 1888 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1889 * It should be droped with fdrop(). 1890 * If it is not set, then the refcount will not be bumped however the 1891 * thread's filedesc struct will be returned locked (for fgetsock). 1892 * 1893 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1894 * Otherwise *fpp is set and zero is returned. 1895 */ 1896 static __inline int 1897 _fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1898 { 1899 struct filedesc *fdp; 1900 struct file *fp; 1901 1902 *fpp = NULL; 1903 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1904 return (EBADF); 1905 FILEDESC_LOCK(fdp); 1906 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1907 FILEDESC_UNLOCK(fdp); 1908 return (EBADF); 1909 } 1910 1911 /* 1912 * Note: FREAD failures returns EBADF to maintain backwards 1913 * compatibility with what routines returned before. 1914 * 1915 * Only one flag, or 0, may be specified. 1916 */ 1917 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1918 FILEDESC_UNLOCK(fdp); 1919 return (EBADF); 1920 } 1921 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1922 FILEDESC_UNLOCK(fdp); 1923 return (EINVAL); 1924 } 1925 if (hold) { 1926 fhold(fp); 1927 FILEDESC_UNLOCK(fdp); 1928 } 1929 *fpp = fp; 1930 return (0); 1931 } 1932 1933 int 1934 fget(struct thread *td, int fd, struct file **fpp) 1935 { 1936 1937 return(_fget(td, fd, fpp, 0, 1)); 1938 } 1939 1940 int 1941 fget_read(struct thread *td, int fd, struct file **fpp) 1942 { 1943 1944 return(_fget(td, fd, fpp, FREAD, 1)); 1945 } 1946 1947 int 1948 fget_write(struct thread *td, int fd, struct file **fpp) 1949 { 1950 1951 return(_fget(td, fd, fpp, FWRITE, 1)); 1952 } 1953 1954 /* 1955 * Like fget() but loads the underlying vnode, or returns an error if 1956 * the descriptor does not represent a vnode. Note that pipes use vnodes 1957 * but never have VM objects (so VOP_GETVOBJECT() calls will return an 1958 * error). The returned vnode will be vref()d. 1959 */ 1960 static __inline int 1961 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 1962 { 1963 struct file *fp; 1964 int error; 1965 1966 *vpp = NULL; 1967 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 1968 return (error); 1969 if (fp->f_vnode == NULL) { 1970 error = EINVAL; 1971 } else { 1972 *vpp = fp->f_vnode; 1973 vref(*vpp); 1974 } 1975 FILEDESC_UNLOCK(td->td_proc->p_fd); 1976 return (error); 1977 } 1978 1979 int 1980 fgetvp(struct thread *td, int fd, struct vnode **vpp) 1981 { 1982 1983 return (_fgetvp(td, fd, vpp, 0)); 1984 } 1985 1986 int 1987 fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 1988 { 1989 1990 return (_fgetvp(td, fd, vpp, FREAD)); 1991 } 1992 1993 int 1994 fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 1995 { 1996 1997 return (_fgetvp(td, fd, vpp, FWRITE)); 1998 } 1999 2000 /* 2001 * Like fget() but loads the underlying socket, or returns an error if 2002 * the descriptor does not represent a socket. 2003 * 2004 * We bump the ref count on the returned socket. XXX Also obtain the SX 2005 * lock in the future. 2006 */ 2007 int 2008 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2009 { 2010 struct file *fp; 2011 int error; 2012 2013 *spp = NULL; 2014 if (fflagp != NULL) 2015 *fflagp = 0; 2016 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2017 return (error); 2018 if (fp->f_type != DTYPE_SOCKET) { 2019 error = ENOTSOCK; 2020 } else { 2021 *spp = fp->f_data; 2022 if (fflagp) 2023 *fflagp = fp->f_flag; 2024 SOCK_LOCK(*spp); 2025 soref(*spp); 2026 SOCK_UNLOCK(*spp); 2027 } 2028 FILEDESC_UNLOCK(td->td_proc->p_fd); 2029 return (error); 2030 } 2031 2032 /* 2033 * Drop the reference count on the the socket and XXX release the SX lock in 2034 * the future. The last reference closes the socket. 2035 */ 2036 void 2037 fputsock(struct socket *so) 2038 { 2039 2040 NET_ASSERT_GIANT(); 2041 SOCK_LOCK(so); 2042 sorele(so); 2043 } 2044 2045 /* 2046 * Drop reference on struct file passed in, may call closef if the 2047 * reference hits zero. 2048 * Expects struct file locked, and will unlock it. 2049 */ 2050 int 2051 fdrop_locked(fp, td) 2052 struct file *fp; 2053 struct thread *td; 2054 { 2055 int error; 2056 2057 FILE_LOCK_ASSERT(fp, MA_OWNED); 2058 2059 if (--fp->f_count > 0) { 2060 FILE_UNLOCK(fp); 2061 return (0); 2062 } 2063 /* We have the last ref so we can proceed without the file lock. */ 2064 FILE_UNLOCK(fp); 2065 if (fp->f_count < 0) 2066 panic("fdrop: count < 0"); 2067 if (fp->f_ops != &badfileops) 2068 error = fo_close(fp, td); 2069 else 2070 error = 0; 2071 ffree(fp); 2072 return (error); 2073 } 2074 2075 /* 2076 * Apply an advisory lock on a file descriptor. 2077 * 2078 * Just attempt to get a record lock of the requested type on 2079 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2080 */ 2081 #ifndef _SYS_SYSPROTO_H_ 2082 struct flock_args { 2083 int fd; 2084 int how; 2085 }; 2086 #endif 2087 /* 2088 * MPSAFE 2089 */ 2090 /* ARGSUSED */ 2091 int 2092 flock(td, uap) 2093 struct thread *td; 2094 struct flock_args *uap; 2095 { 2096 struct file *fp; 2097 struct vnode *vp; 2098 struct flock lf; 2099 int error; 2100 2101 if ((error = fget(td, uap->fd, &fp)) != 0) 2102 return (error); 2103 if (fp->f_type != DTYPE_VNODE) { 2104 fdrop(fp, td); 2105 return (EOPNOTSUPP); 2106 } 2107 2108 mtx_lock(&Giant); 2109 vp = fp->f_vnode; 2110 lf.l_whence = SEEK_SET; 2111 lf.l_start = 0; 2112 lf.l_len = 0; 2113 if (uap->how & LOCK_UN) { 2114 lf.l_type = F_UNLCK; 2115 FILE_LOCK(fp); 2116 fp->f_flag &= ~FHASLOCK; 2117 FILE_UNLOCK(fp); 2118 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2119 goto done2; 2120 } 2121 if (uap->how & LOCK_EX) 2122 lf.l_type = F_WRLCK; 2123 else if (uap->how & LOCK_SH) 2124 lf.l_type = F_RDLCK; 2125 else { 2126 error = EBADF; 2127 goto done2; 2128 } 2129 FILE_LOCK(fp); 2130 fp->f_flag |= FHASLOCK; 2131 FILE_UNLOCK(fp); 2132 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2133 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2134 done2: 2135 fdrop(fp, td); 2136 mtx_unlock(&Giant); 2137 return (error); 2138 } 2139 2140 /* 2141 * File Descriptor pseudo-device driver (/dev/fd/). 2142 * 2143 * Opening minor device N dup()s the file (if any) connected to file 2144 * descriptor N belonging to the calling process. Note that this driver 2145 * consists of only the ``open()'' routine, because all subsequent 2146 * references to this file will be direct to the other driver. 2147 */ 2148 /* ARGSUSED */ 2149 static int 2150 fdopen(dev, mode, type, td) 2151 struct cdev *dev; 2152 int mode, type; 2153 struct thread *td; 2154 { 2155 2156 /* 2157 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2158 * the file descriptor being sought for duplication. The error 2159 * return ensures that the vnode for this device will be released 2160 * by vn_open. Open will detect this special error and take the 2161 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2162 * will simply report the error. 2163 */ 2164 td->td_dupfd = dev2unit(dev); 2165 return (ENODEV); 2166 } 2167 2168 /* 2169 * Duplicate the specified descriptor to a free descriptor. 2170 */ 2171 int 2172 dupfdopen(td, fdp, indx, dfd, mode, error) 2173 struct thread *td; 2174 struct filedesc *fdp; 2175 int indx, dfd; 2176 int mode; 2177 int error; 2178 { 2179 struct file *wfp; 2180 struct file *fp; 2181 2182 /* 2183 * If the to-be-dup'd fd number is greater than the allowed number 2184 * of file descriptors, or the fd to be dup'd has already been 2185 * closed, then reject. 2186 */ 2187 FILEDESC_LOCK(fdp); 2188 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2189 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2190 FILEDESC_UNLOCK(fdp); 2191 return (EBADF); 2192 } 2193 2194 /* 2195 * There are two cases of interest here. 2196 * 2197 * For ENODEV simply dup (dfd) to file descriptor 2198 * (indx) and return. 2199 * 2200 * For ENXIO steal away the file structure from (dfd) and 2201 * store it in (indx). (dfd) is effectively closed by 2202 * this operation. 2203 * 2204 * Any other error code is just returned. 2205 */ 2206 switch (error) { 2207 case ENODEV: 2208 /* 2209 * Check that the mode the file is being opened for is a 2210 * subset of the mode of the existing descriptor. 2211 */ 2212 FILE_LOCK(wfp); 2213 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2214 FILE_UNLOCK(wfp); 2215 FILEDESC_UNLOCK(fdp); 2216 return (EACCES); 2217 } 2218 fp = fdp->fd_ofiles[indx]; 2219 fdp->fd_ofiles[indx] = wfp; 2220 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2221 if (fp == NULL) 2222 fdused(fdp, indx); 2223 fhold_locked(wfp); 2224 FILE_UNLOCK(wfp); 2225 if (fp != NULL) 2226 FILE_LOCK(fp); 2227 FILEDESC_UNLOCK(fdp); 2228 /* 2229 * We now own the reference to fp that the ofiles[] array 2230 * used to own. Release it. 2231 */ 2232 if (fp != NULL) 2233 fdrop_locked(fp, td); 2234 return (0); 2235 2236 case ENXIO: 2237 /* 2238 * Steal away the file pointer from dfd and stuff it into indx. 2239 */ 2240 fp = fdp->fd_ofiles[indx]; 2241 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2242 fdp->fd_ofiles[dfd] = NULL; 2243 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2244 fdp->fd_ofileflags[dfd] = 0; 2245 fdunused(fdp, dfd); 2246 if (fp == NULL) 2247 fdused(fdp, indx); 2248 if (fp != NULL) 2249 FILE_LOCK(fp); 2250 FILEDESC_UNLOCK(fdp); 2251 2252 /* 2253 * we now own the reference to fp that the ofiles[] array 2254 * used to own. Release it. 2255 */ 2256 if (fp != NULL) 2257 fdrop_locked(fp, td); 2258 return (0); 2259 2260 default: 2261 FILEDESC_UNLOCK(fdp); 2262 return (error); 2263 } 2264 /* NOTREACHED */ 2265 } 2266 2267 struct filedesc_to_leader * 2268 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2269 struct filedesc *fdp, 2270 struct proc *leader) 2271 { 2272 struct filedesc_to_leader *fdtol; 2273 2274 MALLOC(fdtol, struct filedesc_to_leader *, 2275 sizeof(struct filedesc_to_leader), 2276 M_FILEDESC_TO_LEADER, 2277 M_WAITOK); 2278 fdtol->fdl_refcount = 1; 2279 fdtol->fdl_holdcount = 0; 2280 fdtol->fdl_wakeup = 0; 2281 fdtol->fdl_leader = leader; 2282 if (old != NULL) { 2283 FILEDESC_LOCK(fdp); 2284 fdtol->fdl_next = old->fdl_next; 2285 fdtol->fdl_prev = old; 2286 old->fdl_next = fdtol; 2287 fdtol->fdl_next->fdl_prev = fdtol; 2288 FILEDESC_UNLOCK(fdp); 2289 } else { 2290 fdtol->fdl_next = fdtol; 2291 fdtol->fdl_prev = fdtol; 2292 } 2293 return (fdtol); 2294 } 2295 2296 /* 2297 * Get file structures. 2298 */ 2299 static int 2300 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2301 { 2302 struct xfile xf; 2303 struct filedesc *fdp; 2304 struct file *fp; 2305 struct proc *p; 2306 int error, n; 2307 2308 /* 2309 * Note: because the number of file descriptors is calculated 2310 * in different ways for sizing vs returning the data, 2311 * there is information leakage from the first loop. However, 2312 * it is of a similar order of magnitude to the leakage from 2313 * global system statistics such as kern.openfiles. 2314 */ 2315 error = sysctl_wire_old_buffer(req, 0); 2316 if (error != 0) 2317 return (error); 2318 if (req->oldptr == NULL) { 2319 n = 16; /* A slight overestimate. */ 2320 sx_slock(&filelist_lock); 2321 LIST_FOREACH(fp, &filehead, f_list) { 2322 /* 2323 * We should grab the lock, but this is an 2324 * estimate, so does it really matter? 2325 */ 2326 /* mtx_lock(fp->f_mtxp); */ 2327 n += fp->f_count; 2328 /* mtx_unlock(f->f_mtxp); */ 2329 } 2330 sx_sunlock(&filelist_lock); 2331 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2332 } 2333 error = 0; 2334 bzero(&xf, sizeof(xf)); 2335 xf.xf_size = sizeof(xf); 2336 sx_slock(&allproc_lock); 2337 LIST_FOREACH(p, &allproc, p_list) { 2338 PROC_LOCK(p); 2339 if (p_cansee(req->td, p) != 0) { 2340 PROC_UNLOCK(p); 2341 continue; 2342 } 2343 xf.xf_pid = p->p_pid; 2344 xf.xf_uid = p->p_ucred->cr_uid; 2345 PROC_UNLOCK(p); 2346 mtx_lock(&fdesc_mtx); 2347 if ((fdp = p->p_fd) == NULL) { 2348 mtx_unlock(&fdesc_mtx); 2349 continue; 2350 } 2351 FILEDESC_LOCK(fdp); 2352 for (n = 0; n < fdp->fd_nfiles; ++n) { 2353 if ((fp = fdp->fd_ofiles[n]) == NULL) 2354 continue; 2355 xf.xf_fd = n; 2356 xf.xf_file = fp; 2357 xf.xf_data = fp->f_data; 2358 xf.xf_vnode = fp->f_vnode; 2359 xf.xf_type = fp->f_type; 2360 xf.xf_count = fp->f_count; 2361 xf.xf_msgcount = fp->f_msgcount; 2362 xf.xf_offset = fp->f_offset; 2363 xf.xf_flag = fp->f_flag; 2364 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2365 if (error) 2366 break; 2367 } 2368 FILEDESC_UNLOCK(fdp); 2369 mtx_unlock(&fdesc_mtx); 2370 if (error) 2371 break; 2372 } 2373 sx_sunlock(&allproc_lock); 2374 return (error); 2375 } 2376 2377 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2378 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2379 2380 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2381 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2382 2383 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2384 &maxfiles, 0, "Maximum number of files"); 2385 2386 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2387 &nfiles, 0, "System-wide number of open files"); 2388 2389 static void 2390 fildesc_drvinit(void *unused) 2391 { 2392 struct cdev *dev; 2393 2394 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2395 make_dev_alias(dev, "stdin"); 2396 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2397 make_dev_alias(dev, "stdout"); 2398 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2399 make_dev_alias(dev, "stderr"); 2400 } 2401 2402 static fo_rdwr_t badfo_readwrite; 2403 static fo_ioctl_t badfo_ioctl; 2404 static fo_poll_t badfo_poll; 2405 static fo_kqfilter_t badfo_kqfilter; 2406 static fo_stat_t badfo_stat; 2407 static fo_close_t badfo_close; 2408 2409 struct fileops badfileops = { 2410 .fo_read = badfo_readwrite, 2411 .fo_write = badfo_readwrite, 2412 .fo_ioctl = badfo_ioctl, 2413 .fo_poll = badfo_poll, 2414 .fo_kqfilter = badfo_kqfilter, 2415 .fo_stat = badfo_stat, 2416 .fo_close = badfo_close, 2417 }; 2418 2419 static int 2420 badfo_readwrite(fp, uio, active_cred, flags, td) 2421 struct file *fp; 2422 struct uio *uio; 2423 struct ucred *active_cred; 2424 struct thread *td; 2425 int flags; 2426 { 2427 2428 return (EBADF); 2429 } 2430 2431 static int 2432 badfo_ioctl(fp, com, data, active_cred, td) 2433 struct file *fp; 2434 u_long com; 2435 void *data; 2436 struct ucred *active_cred; 2437 struct thread *td; 2438 { 2439 2440 return (EBADF); 2441 } 2442 2443 static int 2444 badfo_poll(fp, events, active_cred, td) 2445 struct file *fp; 2446 int events; 2447 struct ucred *active_cred; 2448 struct thread *td; 2449 { 2450 2451 return (0); 2452 } 2453 2454 static int 2455 badfo_kqfilter(fp, kn) 2456 struct file *fp; 2457 struct knote *kn; 2458 { 2459 2460 return (0); 2461 } 2462 2463 static int 2464 badfo_stat(fp, sb, active_cred, td) 2465 struct file *fp; 2466 struct stat *sb; 2467 struct ucred *active_cred; 2468 struct thread *td; 2469 { 2470 2471 return (EBADF); 2472 } 2473 2474 static int 2475 badfo_close(fp, td) 2476 struct file *fp; 2477 struct thread *td; 2478 { 2479 2480 return (EBADF); 2481 } 2482 2483 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2484 fildesc_drvinit,NULL) 2485 2486 static void filelistinit(void *); 2487 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2488 2489 /* ARGSUSED*/ 2490 static void 2491 filelistinit(dummy) 2492 void *dummy; 2493 { 2494 2495 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2496 NULL, NULL, UMA_ALIGN_PTR, 0); 2497 sx_init(&filelist_lock, "filelist lock"); 2498 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2499 } 2500