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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 39 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $ 40 * $DragonFly: src/sys/kern/kern_descrip.c,v 1.27 2004/07/29 20:32:24 dillon Exp $ 41 */ 42 43 #include "opt_compat.h" 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/malloc.h> 47 #include <sys/sysproto.h> 48 #include <sys/conf.h> 49 #include <sys/filedesc.h> 50 #include <sys/kernel.h> 51 #include <sys/sysctl.h> 52 #include <sys/vnode.h> 53 #include <sys/proc.h> 54 #include <sys/namei.h> 55 #include <sys/file.h> 56 #include <sys/stat.h> 57 #include <sys/filio.h> 58 #include <sys/fcntl.h> 59 #include <sys/unistd.h> 60 #include <sys/resourcevar.h> 61 #include <sys/event.h> 62 #include <sys/kern_syscall.h> 63 64 #include <vm/vm.h> 65 #include <vm/vm_extern.h> 66 67 #include <sys/file2.h> 68 69 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 70 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 71 "file desc to leader structures"); 72 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 73 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 74 75 static d_open_t fdopen; 76 #define NUMFDESC 64 77 78 #define CDEV_MAJOR 22 79 static struct cdevsw fildesc_cdevsw = { 80 /* name */ "FD", 81 /* maj */ CDEV_MAJOR, 82 /* flags */ 0, 83 /* port */ NULL, 84 /* clone */ NULL, 85 86 /* open */ fdopen, 87 /* close */ noclose, 88 /* read */ noread, 89 /* write */ nowrite, 90 /* ioctl */ noioctl, 91 /* poll */ nopoll, 92 /* mmap */ nommap, 93 /* strategy */ nostrategy, 94 /* dump */ nodump, 95 /* psize */ nopsize 96 }; 97 98 static int badfo_readwrite (struct file *fp, struct uio *uio, 99 struct ucred *cred, int flags, struct thread *td); 100 static int badfo_ioctl (struct file *fp, u_long com, caddr_t data, 101 struct thread *td); 102 static int badfo_poll (struct file *fp, int events, 103 struct ucred *cred, struct thread *td); 104 static int badfo_kqfilter (struct file *fp, struct knote *kn); 105 static int badfo_stat (struct file *fp, struct stat *sb, struct thread *td); 106 static int badfo_close (struct file *fp, struct thread *td); 107 108 /* 109 * Descriptor management. 110 */ 111 struct filelist filehead; /* head of list of open files */ 112 int nfiles; /* actual number of open files */ 113 extern int cmask; 114 115 /* 116 * System calls on descriptors. 117 */ 118 /* ARGSUSED */ 119 int 120 getdtablesize(struct getdtablesize_args *uap) 121 { 122 struct proc *p = curproc; 123 124 uap->sysmsg_result = 125 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 126 return (0); 127 } 128 129 /* 130 * Duplicate a file descriptor to a particular value. 131 * 132 * note: keep in mind that a potential race condition exists when closing 133 * descriptors from a shared descriptor table (via rfork). 134 */ 135 /* ARGSUSED */ 136 int 137 dup2(struct dup2_args *uap) 138 { 139 int error; 140 141 error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds); 142 143 return (error); 144 } 145 146 /* 147 * Duplicate a file descriptor. 148 */ 149 /* ARGSUSED */ 150 int 151 dup(struct dup_args *uap) 152 { 153 int error; 154 155 error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds); 156 157 return (error); 158 } 159 160 int 161 kern_fcntl(int fd, int cmd, union fcntl_dat *dat) 162 { 163 struct thread *td = curthread; 164 struct proc *p = td->td_proc; 165 struct filedesc *fdp = p->p_fd; 166 struct file *fp; 167 char *pop; 168 struct vnode *vp; 169 u_int newmin; 170 int tmp, error, flg = F_POSIX; 171 172 KKASSERT(p); 173 174 if ((unsigned)fd >= fdp->fd_nfiles || 175 (fp = fdp->fd_ofiles[fd]) == NULL) 176 return (EBADF); 177 pop = &fdp->fd_ofileflags[fd]; 178 179 switch (cmd) { 180 case F_DUPFD: 181 newmin = dat->fc_fd; 182 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 183 newmin > maxfilesperproc) 184 return (EINVAL); 185 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); 186 return (error); 187 188 case F_GETFD: 189 dat->fc_cloexec = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 190 return (0); 191 192 case F_SETFD: 193 *pop = (*pop &~ UF_EXCLOSE) | 194 (dat->fc_cloexec & FD_CLOEXEC ? UF_EXCLOSE : 0); 195 return (0); 196 197 case F_GETFL: 198 dat->fc_flags = OFLAGS(fp->f_flag); 199 return (0); 200 201 case F_SETFL: 202 fhold(fp); 203 fp->f_flag &= ~FCNTLFLAGS; 204 fp->f_flag |= FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 205 tmp = fp->f_flag & FNONBLOCK; 206 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td); 207 if (error) { 208 fdrop(fp, td); 209 return (error); 210 } 211 tmp = fp->f_flag & FASYNC; 212 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, td); 213 if (!error) { 214 fdrop(fp, td); 215 return (0); 216 } 217 fp->f_flag &= ~FNONBLOCK; 218 tmp = 0; 219 fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td); 220 fdrop(fp, td); 221 return (error); 222 223 case F_GETOWN: 224 fhold(fp); 225 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, td); 226 fdrop(fp, td); 227 return(error); 228 229 case F_SETOWN: 230 fhold(fp); 231 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, td); 232 fdrop(fp, td); 233 return(error); 234 235 case F_SETLKW: 236 flg |= F_WAIT; 237 /* Fall into F_SETLK */ 238 239 case F_SETLK: 240 if (fp->f_type != DTYPE_VNODE) 241 return (EBADF); 242 vp = (struct vnode *)fp->f_data; 243 244 /* 245 * copyin/lockop may block 246 */ 247 fhold(fp); 248 if (dat->fc_flock.l_whence == SEEK_CUR) 249 dat->fc_flock.l_start += fp->f_offset; 250 251 switch (dat->fc_flock.l_type) { 252 case F_RDLCK: 253 if ((fp->f_flag & FREAD) == 0) { 254 error = EBADF; 255 break; 256 } 257 p->p_leader->p_flag |= P_ADVLOCK; 258 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 259 &dat->fc_flock, flg); 260 break; 261 case F_WRLCK: 262 if ((fp->f_flag & FWRITE) == 0) { 263 error = EBADF; 264 break; 265 } 266 p->p_leader->p_flag |= P_ADVLOCK; 267 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 268 &dat->fc_flock, flg); 269 break; 270 case F_UNLCK: 271 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 272 &dat->fc_flock, F_POSIX); 273 break; 274 default: 275 error = EINVAL; 276 break; 277 } 278 /* Check for race with close */ 279 if ((unsigned) fd >= fdp->fd_nfiles || 280 fp != fdp->fd_ofiles[fd]) { 281 dat->fc_flock.l_whence = SEEK_SET; 282 dat->fc_flock.l_start = 0; 283 dat->fc_flock.l_len = 0; 284 dat->fc_flock.l_type = F_UNLCK; 285 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 286 F_UNLCK, &dat->fc_flock, F_POSIX); 287 } 288 fdrop(fp, td); 289 return(error); 290 291 case F_GETLK: 292 if (fp->f_type != DTYPE_VNODE) 293 return (EBADF); 294 vp = (struct vnode *)fp->f_data; 295 /* 296 * copyin/lockop may block 297 */ 298 fhold(fp); 299 if (dat->fc_flock.l_type != F_RDLCK && 300 dat->fc_flock.l_type != F_WRLCK && 301 dat->fc_flock.l_type != F_UNLCK) { 302 fdrop(fp, td); 303 return (EINVAL); 304 } 305 if (dat->fc_flock.l_whence == SEEK_CUR) 306 dat->fc_flock.l_start += fp->f_offset; 307 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 308 &dat->fc_flock, F_POSIX); 309 fdrop(fp, td); 310 return(error); 311 default: 312 return (EINVAL); 313 } 314 /* NOTREACHED */ 315 } 316 317 /* 318 * The file control system call. 319 */ 320 int 321 fcntl(struct fcntl_args *uap) 322 { 323 union fcntl_dat dat; 324 int error; 325 326 switch (uap->cmd) { 327 case F_DUPFD: 328 dat.fc_fd = uap->arg; 329 break; 330 case F_SETFD: 331 dat.fc_cloexec = uap->arg; 332 break; 333 case F_SETFL: 334 dat.fc_flags = uap->arg; 335 break; 336 case F_SETOWN: 337 dat.fc_owner = uap->arg; 338 break; 339 case F_SETLKW: 340 case F_SETLK: 341 case F_GETLK: 342 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 343 sizeof(struct flock)); 344 if (error) 345 return (error); 346 break; 347 } 348 349 error = kern_fcntl(uap->fd, uap->cmd, &dat); 350 351 if (error == 0) { 352 switch (uap->cmd) { 353 case F_DUPFD: 354 uap->sysmsg_result = dat.fc_fd; 355 break; 356 case F_GETFD: 357 uap->sysmsg_result = dat.fc_cloexec; 358 break; 359 case F_GETFL: 360 uap->sysmsg_result = dat.fc_flags; 361 break; 362 case F_GETOWN: 363 uap->sysmsg_result = dat.fc_owner; 364 case F_GETLK: 365 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 366 sizeof(struct flock)); 367 break; 368 } 369 } 370 371 return (error); 372 } 373 374 /* 375 * Common code for dup, dup2, and fcntl(F_DUPFD). 376 * 377 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells 378 * kern_dup() to destructively dup over an existing file descriptor if new 379 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest 380 * unused file descriptor that is greater than or equal to new. 381 */ 382 int 383 kern_dup(enum dup_type type, int old, int new, int *res) 384 { 385 struct thread *td = curthread; 386 struct proc *p = td->td_proc; 387 struct filedesc *fdp = p->p_fd; 388 struct file *fp; 389 struct file *delfp; 390 int holdleaders; 391 int error, newfd; 392 393 /* 394 * Verify that we have a valid descriptor to dup from and 395 * possibly to dup to. 396 */ 397 if (old < 0 || new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 398 new >= maxfilesperproc) 399 return (EBADF); 400 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) 401 return (EBADF); 402 if (type == DUP_FIXED && old == new) { 403 *res = new; 404 return (0); 405 } 406 fp = fdp->fd_ofiles[old]; 407 fhold(fp); 408 409 /* 410 * Expand the table for the new descriptor if needed. This may 411 * block and drop and reacquire the fidedesc lock. 412 */ 413 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) { 414 error = fdalloc(p, new, &newfd); 415 if (error) { 416 fdrop(fp, td); 417 return (error); 418 } 419 } 420 if (type == DUP_VARIABLE) 421 new = newfd; 422 423 /* 424 * If the old file changed out from under us then treat it as a 425 * bad file descriptor. Userland should do its own locking to 426 * avoid this case. 427 */ 428 if (fdp->fd_ofiles[old] != fp) { 429 if (fdp->fd_ofiles[new] == NULL) { 430 if (new < fdp->fd_freefile) 431 fdp->fd_freefile = new; 432 while (fdp->fd_lastfile > 0 && 433 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 434 fdp->fd_lastfile--; 435 } 436 fdrop(fp, td); 437 return (EBADF); 438 } 439 KASSERT(old != new, ("new fd is same as old")); 440 441 /* 442 * Save info on the descriptor being overwritten. We have 443 * to do the unmap now, but we cannot close it without 444 * introducing an ownership race for the slot. 445 */ 446 delfp = fdp->fd_ofiles[new]; 447 if (delfp != NULL && p->p_fdtol != NULL) { 448 /* 449 * Ask fdfree() to sleep to ensure that all relevant 450 * process leaders can be traversed in closef(). 451 */ 452 fdp->fd_holdleaderscount++; 453 holdleaders = 1; 454 } else 455 holdleaders = 0; 456 KASSERT(delfp == NULL || type == DUP_FIXED, 457 ("dup() picked an open file")); 458 #if 0 459 if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED)) 460 (void) munmapfd(p, new); 461 #endif 462 463 /* 464 * Duplicate the source descriptor, update lastfile 465 */ 466 fdp->fd_ofiles[new] = fp; 467 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 468 if (new > fdp->fd_lastfile) 469 fdp->fd_lastfile = new; 470 *res = new; 471 472 /* 473 * If we dup'd over a valid file, we now own the reference to it 474 * and must dispose of it using closef() semantics (as if a 475 * close() were performed on it). 476 */ 477 if (delfp) { 478 (void) closef(delfp, td); 479 if (holdleaders) { 480 fdp->fd_holdleaderscount--; 481 if (fdp->fd_holdleaderscount == 0 && 482 fdp->fd_holdleaderswakeup != 0) { 483 fdp->fd_holdleaderswakeup = 0; 484 wakeup(&fdp->fd_holdleaderscount); 485 } 486 } 487 } 488 return (0); 489 } 490 491 /* 492 * If sigio is on the list associated with a process or process group, 493 * disable signalling from the device, remove sigio from the list and 494 * free sigio. 495 */ 496 void 497 funsetown(struct sigio *sigio) 498 { 499 int s; 500 501 if (sigio == NULL) 502 return; 503 s = splhigh(); 504 *(sigio->sio_myref) = NULL; 505 splx(s); 506 if (sigio->sio_pgid < 0) { 507 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 508 sigio, sio_pgsigio); 509 } else /* if ((*sigiop)->sio_pgid > 0) */ { 510 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 511 sigio, sio_pgsigio); 512 } 513 crfree(sigio->sio_ucred); 514 free(sigio, M_SIGIO); 515 } 516 517 /* Free a list of sigio structures. */ 518 void 519 funsetownlst(struct sigiolst *sigiolst) 520 { 521 struct sigio *sigio; 522 523 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 524 funsetown(sigio); 525 } 526 527 /* 528 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 529 * 530 * After permission checking, add a sigio structure to the sigio list for 531 * the process or process group. 532 */ 533 int 534 fsetown(pid_t pgid, struct sigio **sigiop) 535 { 536 struct proc *proc; 537 struct pgrp *pgrp; 538 struct sigio *sigio; 539 int s; 540 541 if (pgid == 0) { 542 funsetown(*sigiop); 543 return (0); 544 } 545 if (pgid > 0) { 546 proc = pfind(pgid); 547 if (proc == NULL) 548 return (ESRCH); 549 550 /* 551 * Policy - Don't allow a process to FSETOWN a process 552 * in another session. 553 * 554 * Remove this test to allow maximum flexibility or 555 * restrict FSETOWN to the current process or process 556 * group for maximum safety. 557 */ 558 if (proc->p_session != curproc->p_session) 559 return (EPERM); 560 561 pgrp = NULL; 562 } else /* if (pgid < 0) */ { 563 pgrp = pgfind(-pgid); 564 if (pgrp == NULL) 565 return (ESRCH); 566 567 /* 568 * Policy - Don't allow a process to FSETOWN a process 569 * in another session. 570 * 571 * Remove this test to allow maximum flexibility or 572 * restrict FSETOWN to the current process or process 573 * group for maximum safety. 574 */ 575 if (pgrp->pg_session != curproc->p_session) 576 return (EPERM); 577 578 proc = NULL; 579 } 580 funsetown(*sigiop); 581 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); 582 if (pgid > 0) { 583 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 584 sigio->sio_proc = proc; 585 } else { 586 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 587 sigio->sio_pgrp = pgrp; 588 } 589 sigio->sio_pgid = pgid; 590 sigio->sio_ucred = crhold(curproc->p_ucred); 591 /* It would be convenient if p_ruid was in ucred. */ 592 sigio->sio_ruid = curproc->p_ucred->cr_ruid; 593 sigio->sio_myref = sigiop; 594 s = splhigh(); 595 *sigiop = sigio; 596 splx(s); 597 return (0); 598 } 599 600 /* 601 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 602 */ 603 pid_t 604 fgetown(struct sigio *sigio) 605 { 606 return (sigio != NULL ? sigio->sio_pgid : 0); 607 } 608 609 /* 610 * Close a file descriptor. 611 */ 612 /* ARGSUSED */ 613 int 614 close(struct close_args *uap) 615 { 616 struct thread *td = curthread; 617 struct proc *p = td->td_proc; 618 struct filedesc *fdp; 619 struct file *fp; 620 int fd = uap->fd; 621 int error; 622 int holdleaders; 623 624 KKASSERT(p); 625 fdp = p->p_fd; 626 627 if ((unsigned)fd >= fdp->fd_nfiles || 628 (fp = fdp->fd_ofiles[fd]) == NULL) 629 return (EBADF); 630 #if 0 631 if (fdp->fd_ofileflags[fd] & UF_MAPPED) 632 (void) munmapfd(p, fd); 633 #endif 634 fdp->fd_ofiles[fd] = NULL; 635 fdp->fd_ofileflags[fd] = 0; 636 holdleaders = 0; 637 if (p->p_fdtol != NULL) { 638 /* 639 * Ask fdfree() to sleep to ensure that all relevant 640 * process leaders can be traversed in closef(). 641 */ 642 fdp->fd_holdleaderscount++; 643 holdleaders = 1; 644 } 645 646 /* 647 * we now hold the fp reference that used to be owned by the descriptor 648 * array. 649 */ 650 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 651 fdp->fd_lastfile--; 652 if (fd < fdp->fd_freefile) 653 fdp->fd_freefile = fd; 654 if (fd < fdp->fd_knlistsize) 655 knote_fdclose(p, fd); 656 error = closef(fp, td); 657 if (holdleaders) { 658 fdp->fd_holdleaderscount--; 659 if (fdp->fd_holdleaderscount == 0 && 660 fdp->fd_holdleaderswakeup != 0) { 661 fdp->fd_holdleaderswakeup = 0; 662 wakeup(&fdp->fd_holdleaderscount); 663 } 664 } 665 return (error); 666 } 667 668 int 669 kern_fstat(int fd, struct stat *ub) 670 { 671 struct thread *td = curthread; 672 struct proc *p = td->td_proc; 673 struct filedesc *fdp; 674 struct file *fp; 675 int error; 676 677 KKASSERT(p); 678 679 fdp = p->p_fd; 680 if ((unsigned)fd >= fdp->fd_nfiles || 681 (fp = fdp->fd_ofiles[fd]) == NULL) 682 return (EBADF); 683 fhold(fp); 684 error = fo_stat(fp, ub, td); 685 fdrop(fp, td); 686 687 return (error); 688 } 689 690 /* 691 * Return status information about a file descriptor. 692 */ 693 int 694 fstat(struct fstat_args *uap) 695 { 696 struct stat st; 697 int error; 698 699 error = kern_fstat(uap->fd, &st); 700 701 if (error == 0) 702 error = copyout(&st, uap->sb, sizeof(st)); 703 return (error); 704 } 705 706 /* 707 * XXX: This is for source compatibility with NetBSD. Probably doesn't 708 * belong here. 709 */ 710 int 711 nfstat(struct nfstat_args *uap) 712 { 713 struct stat st; 714 struct nstat nst; 715 int error; 716 717 error = kern_fstat(uap->fd, &st); 718 719 if (error == 0) { 720 cvtnstat(&st, &nst); 721 error = copyout(&nst, uap->sb, sizeof (nst)); 722 } 723 return (error); 724 } 725 726 /* 727 * Return pathconf information about a file descriptor. 728 */ 729 /* ARGSUSED */ 730 int 731 fpathconf(struct fpathconf_args *uap) 732 { 733 struct thread *td = curthread; 734 struct proc *p = td->td_proc; 735 struct filedesc *fdp; 736 struct file *fp; 737 struct vnode *vp; 738 int error = 0; 739 740 KKASSERT(p); 741 fdp = p->p_fd; 742 if ((unsigned)uap->fd >= fdp->fd_nfiles || 743 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 744 return (EBADF); 745 746 fhold(fp); 747 748 switch (fp->f_type) { 749 case DTYPE_PIPE: 750 case DTYPE_SOCKET: 751 if (uap->name != _PC_PIPE_BUF) { 752 error = EINVAL; 753 } else { 754 uap->sysmsg_result = PIPE_BUF; 755 error = 0; 756 } 757 break; 758 case DTYPE_FIFO: 759 case DTYPE_VNODE: 760 vp = (struct vnode *)fp->f_data; 761 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds); 762 break; 763 default: 764 error = EOPNOTSUPP; 765 break; 766 } 767 fdrop(fp, td); 768 return(error); 769 } 770 771 /* 772 * Allocate a file descriptor for the process. 773 */ 774 static int fdexpand; 775 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, ""); 776 777 int 778 fdalloc(struct proc *p, int want, int *result) 779 { 780 struct filedesc *fdp = p->p_fd; 781 int i; 782 int lim, last, nfiles; 783 struct file **newofile; 784 char *newofileflags; 785 786 /* 787 * Search for a free descriptor starting at the higher 788 * of want or fd_freefile. If that fails, consider 789 * expanding the ofile array. 790 */ 791 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 792 for (;;) { 793 last = min(fdp->fd_nfiles, lim); 794 if ((i = want) < fdp->fd_freefile) 795 i = fdp->fd_freefile; 796 for (; i < last; i++) { 797 if (fdp->fd_ofiles[i] == NULL) { 798 fdp->fd_ofileflags[i] = 0; 799 if (i > fdp->fd_lastfile) 800 fdp->fd_lastfile = i; 801 if (want <= fdp->fd_freefile) 802 fdp->fd_freefile = i; 803 *result = i; 804 return (0); 805 } 806 } 807 808 /* 809 * No space in current array. Expand? 810 */ 811 if (fdp->fd_nfiles >= lim) 812 return (EMFILE); 813 if (fdp->fd_nfiles < NDEXTENT) 814 nfiles = NDEXTENT; 815 else 816 nfiles = 2 * fdp->fd_nfiles; 817 newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK); 818 819 /* 820 * deal with file-table extend race that might have occured 821 * when malloc was blocked. 822 */ 823 if (fdp->fd_nfiles >= nfiles) { 824 free(newofile, M_FILEDESC); 825 continue; 826 } 827 newofileflags = (char *) &newofile[nfiles]; 828 /* 829 * Copy the existing ofile and ofileflags arrays 830 * and zero the new portion of each array. 831 */ 832 bcopy(fdp->fd_ofiles, newofile, 833 (i = sizeof(struct file *) * fdp->fd_nfiles)); 834 bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i); 835 bcopy(fdp->fd_ofileflags, newofileflags, 836 (i = sizeof(char) * fdp->fd_nfiles)); 837 bzero(newofileflags + i, nfiles * sizeof(char) - i); 838 if (fdp->fd_nfiles > NDFILE) 839 free(fdp->fd_ofiles, M_FILEDESC); 840 fdp->fd_ofiles = newofile; 841 fdp->fd_ofileflags = newofileflags; 842 fdp->fd_nfiles = nfiles; 843 fdexpand++; 844 } 845 return (0); 846 } 847 848 /* 849 * Check to see whether n user file descriptors 850 * are available to the process p. 851 */ 852 int 853 fdavail(struct proc *p, int n) 854 { 855 struct filedesc *fdp = p->p_fd; 856 struct file **fpp; 857 int i, lim, last; 858 859 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 860 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 861 return (1); 862 863 last = min(fdp->fd_nfiles, lim); 864 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 865 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 866 if (*fpp == NULL && --n <= 0) 867 return (1); 868 } 869 return (0); 870 } 871 872 /* 873 * falloc: 874 * Create a new open file structure and allocate a file decriptor 875 * for the process that refers to it. If p is NULL, no descriptor 876 * is allocated and the file pointer is returned unassociated with 877 * any process. resultfd is only used if p is not NULL and may 878 * separately be NULL indicating that you don't need the returned fd. 879 */ 880 int 881 falloc(struct proc *p, struct file **resultfp, int *resultfd) 882 { 883 struct file *fp, *fq; 884 int error, i; 885 static struct timeval lastfail; 886 static int curfail; 887 888 if (nfiles >= maxfiles - maxfilesrootres && 889 ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) { 890 if (ppsratecheck(&lastfail, &curfail, 1)) { 891 printf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n", 892 (p ? p->p_ucred->cr_ruid : -1)); 893 } 894 return (ENFILE); 895 } 896 /* 897 * Allocate a new file descriptor. 898 * If the process has file descriptor zero open, add to the list 899 * of open files at that point, otherwise put it at the front of 900 * the list of open files. 901 */ 902 nfiles++; 903 fp = malloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 904 905 /* 906 * wait until after malloc (which may have blocked) returns before 907 * allocating the slot, else a race might have shrunk it if we had 908 * allocated it before the malloc. 909 */ 910 i = -1; 911 if (p && (error = fdalloc(p, 0, &i))) { 912 nfiles--; 913 free(fp, M_FILE); 914 return (error); 915 } 916 fp->f_count = 1; 917 fp->f_ops = &badfileops; 918 fp->f_seqcount = 1; 919 if (p) { 920 fp->f_cred = crhold(p->p_ucred); 921 if ((fq = p->p_fd->fd_ofiles[0]) != NULL) { 922 LIST_INSERT_AFTER(fq, fp, f_list); 923 } else { 924 LIST_INSERT_HEAD(&filehead, fp, f_list); 925 } 926 p->p_fd->fd_ofiles[i] = fp; 927 } else { 928 fp->f_cred = crhold(proc0.p_ucred); 929 LIST_INSERT_HEAD(&filehead, fp, f_list); 930 } 931 if (resultfp) 932 *resultfp = fp; 933 if (resultfd) 934 *resultfd = i; 935 return (0); 936 } 937 938 void 939 fsetcred(struct file *fp, struct ucred *cr) 940 { 941 crhold(cr); 942 crfree(fp->f_cred); 943 fp->f_cred = cr; 944 } 945 946 /* 947 * Free a file descriptor. 948 */ 949 void 950 ffree(struct file *fp) 951 { 952 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 953 LIST_REMOVE(fp, f_list); 954 crfree(fp->f_cred); 955 nfiles--; 956 free(fp, M_FILE); 957 } 958 959 /* 960 * Build a new filedesc structure. 961 */ 962 struct filedesc * 963 fdinit(struct proc *p) 964 { 965 struct filedesc0 *newfdp; 966 struct filedesc *fdp = p->p_fd; 967 968 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK|M_ZERO); 969 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 970 if (newfdp->fd_fd.fd_cdir) 971 vref(newfdp->fd_fd.fd_cdir); 972 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 973 vref(newfdp->fd_fd.fd_rdir); 974 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 975 if (newfdp->fd_fd.fd_jdir) 976 vref(newfdp->fd_fd.fd_jdir); 977 978 /* Create the file descriptor table. */ 979 newfdp->fd_fd.fd_refcnt = 1; 980 newfdp->fd_fd.fd_cmask = cmask; 981 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 982 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 983 newfdp->fd_fd.fd_nfiles = NDFILE; 984 newfdp->fd_fd.fd_knlistsize = -1; 985 986 return (&newfdp->fd_fd); 987 } 988 989 /* 990 * Share a filedesc structure. 991 */ 992 struct filedesc * 993 fdshare(struct proc *p) 994 { 995 p->p_fd->fd_refcnt++; 996 return (p->p_fd); 997 } 998 999 /* 1000 * Copy a filedesc structure. 1001 */ 1002 struct filedesc * 1003 fdcopy(struct proc *p) 1004 { 1005 struct filedesc *newfdp, *fdp = p->p_fd; 1006 struct file **fpp; 1007 int i; 1008 1009 /* Certain daemons might not have file descriptors. */ 1010 if (fdp == NULL) 1011 return (NULL); 1012 1013 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK); 1014 bcopy(fdp, newfdp, sizeof(struct filedesc)); 1015 if (newfdp->fd_cdir) 1016 vref(newfdp->fd_cdir); 1017 /* 1018 * We must check for fd_rdir here, at least for now because 1019 * the init process is created before we have access to the 1020 * rootvode to take a reference to it. 1021 */ 1022 if (newfdp->fd_rdir) 1023 vref(newfdp->fd_rdir); 1024 if (newfdp->fd_jdir) 1025 vref(newfdp->fd_jdir); 1026 newfdp->fd_refcnt = 1; 1027 1028 /* 1029 * If the number of open files fits in the internal arrays 1030 * of the open file structure, use them, otherwise allocate 1031 * additional memory for the number of descriptors currently 1032 * in use. 1033 */ 1034 if (newfdp->fd_lastfile < NDFILE) { 1035 newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles; 1036 newfdp->fd_ofileflags = 1037 ((struct filedesc0 *) newfdp)->fd_dfileflags; 1038 i = NDFILE; 1039 } else { 1040 /* 1041 * Compute the smallest multiple of NDEXTENT needed 1042 * for the file descriptors currently in use, 1043 * allowing the table to shrink. 1044 */ 1045 i = newfdp->fd_nfiles; 1046 while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2) 1047 i /= 2; 1048 newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK); 1049 newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i]; 1050 } 1051 newfdp->fd_nfiles = i; 1052 bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **)); 1053 bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char)); 1054 1055 /* 1056 * kq descriptors cannot be copied. 1057 */ 1058 if (newfdp->fd_knlistsize != -1) { 1059 fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile]; 1060 for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) { 1061 if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) { 1062 *fpp = NULL; 1063 if (i < newfdp->fd_freefile) 1064 newfdp->fd_freefile = i; 1065 } 1066 if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0) 1067 newfdp->fd_lastfile--; 1068 } 1069 newfdp->fd_knlist = NULL; 1070 newfdp->fd_knlistsize = -1; 1071 newfdp->fd_knhash = NULL; 1072 newfdp->fd_knhashmask = 0; 1073 } 1074 1075 fpp = newfdp->fd_ofiles; 1076 for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) { 1077 if (*fpp != NULL) 1078 fhold(*fpp); 1079 } 1080 return (newfdp); 1081 } 1082 1083 /* 1084 * Release a filedesc structure. 1085 */ 1086 void 1087 fdfree(struct proc *p) 1088 { 1089 struct thread *td = p->p_thread; 1090 struct filedesc *fdp = p->p_fd; 1091 struct file **fpp; 1092 int i; 1093 struct filedesc_to_leader *fdtol; 1094 struct file *fp; 1095 struct vnode *vp; 1096 struct flock lf; 1097 1098 /* Certain daemons might not have file descriptors. */ 1099 if (fdp == NULL) 1100 return; 1101 1102 /* Check for special need to clear POSIX style locks */ 1103 fdtol = p->p_fdtol; 1104 if (fdtol != NULL) { 1105 KASSERT(fdtol->fdl_refcount > 0, 1106 ("filedesc_to_refcount botch: fdl_refcount=%d", 1107 fdtol->fdl_refcount)); 1108 if (fdtol->fdl_refcount == 1 && 1109 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1110 i = 0; 1111 fpp = fdp->fd_ofiles; 1112 for (i = 0, fpp = fdp->fd_ofiles; 1113 i <= fdp->fd_lastfile; 1114 i++, fpp++) { 1115 if (*fpp == NULL || 1116 (*fpp)->f_type != DTYPE_VNODE) 1117 continue; 1118 fp = *fpp; 1119 fhold(fp); 1120 lf.l_whence = SEEK_SET; 1121 lf.l_start = 0; 1122 lf.l_len = 0; 1123 lf.l_type = F_UNLCK; 1124 vp = (struct vnode *)fp->f_data; 1125 (void) VOP_ADVLOCK(vp, 1126 (caddr_t)p->p_leader, 1127 F_UNLCK, 1128 &lf, 1129 F_POSIX); 1130 fdrop(fp, p->p_thread); 1131 fpp = fdp->fd_ofiles + i; 1132 } 1133 } 1134 retry: 1135 if (fdtol->fdl_refcount == 1) { 1136 if (fdp->fd_holdleaderscount > 0 && 1137 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1138 /* 1139 * close() or do_dup() has cleared a reference 1140 * in a shared file descriptor table. 1141 */ 1142 fdp->fd_holdleaderswakeup = 1; 1143 tsleep(&fdp->fd_holdleaderscount, 1144 0, "fdlhold", 0); 1145 goto retry; 1146 } 1147 if (fdtol->fdl_holdcount > 0) { 1148 /* 1149 * Ensure that fdtol->fdl_leader 1150 * remains valid in closef(). 1151 */ 1152 fdtol->fdl_wakeup = 1; 1153 tsleep(fdtol, 0, "fdlhold", 0); 1154 goto retry; 1155 } 1156 } 1157 fdtol->fdl_refcount--; 1158 if (fdtol->fdl_refcount == 0 && 1159 fdtol->fdl_holdcount == 0) { 1160 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1161 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1162 } else 1163 fdtol = NULL; 1164 p->p_fdtol = NULL; 1165 if (fdtol != NULL) 1166 free(fdtol, M_FILEDESC_TO_LEADER); 1167 } 1168 if (--fdp->fd_refcnt > 0) 1169 return; 1170 /* 1171 * we are the last reference to the structure, we can 1172 * safely assume it will not change out from under us. 1173 */ 1174 fpp = fdp->fd_ofiles; 1175 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1176 if (*fpp) 1177 (void) closef(*fpp, td); 1178 } 1179 if (fdp->fd_nfiles > NDFILE) 1180 free(fdp->fd_ofiles, M_FILEDESC); 1181 if (fdp->fd_cdir) 1182 vrele(fdp->fd_cdir); 1183 vrele(fdp->fd_rdir); 1184 if (fdp->fd_jdir) 1185 vrele(fdp->fd_jdir); 1186 if (fdp->fd_knlist) 1187 free(fdp->fd_knlist, M_KQUEUE); 1188 if (fdp->fd_knhash) 1189 free(fdp->fd_knhash, M_KQUEUE); 1190 free(fdp, M_FILEDESC); 1191 } 1192 1193 /* 1194 * For setugid programs, we don't want to people to use that setugidness 1195 * to generate error messages which write to a file which otherwise would 1196 * otherwise be off-limits to the process. 1197 * 1198 * This is a gross hack to plug the hole. A better solution would involve 1199 * a special vop or other form of generalized access control mechanism. We 1200 * go ahead and just reject all procfs file systems accesses as dangerous. 1201 * 1202 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1203 * sufficient. We also don't for check setugidness since we know we are. 1204 */ 1205 static int 1206 is_unsafe(struct file *fp) 1207 { 1208 if (fp->f_type == DTYPE_VNODE && 1209 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 1210 return (1); 1211 return (0); 1212 } 1213 1214 /* 1215 * Make this setguid thing safe, if at all possible. 1216 */ 1217 void 1218 setugidsafety(struct proc *p) 1219 { 1220 struct thread *td = p->p_thread; 1221 struct filedesc *fdp = p->p_fd; 1222 int i; 1223 1224 /* Certain daemons might not have file descriptors. */ 1225 if (fdp == NULL) 1226 return; 1227 1228 /* 1229 * note: fdp->fd_ofiles may be reallocated out from under us while 1230 * we are blocked in a close. Be careful! 1231 */ 1232 for (i = 0; i <= fdp->fd_lastfile; i++) { 1233 if (i > 2) 1234 break; 1235 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1236 struct file *fp; 1237 1238 #if 0 1239 if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0) 1240 (void) munmapfd(p, i); 1241 #endif 1242 if (i < fdp->fd_knlistsize) 1243 knote_fdclose(p, i); 1244 /* 1245 * NULL-out descriptor prior to close to avoid 1246 * a race while close blocks. 1247 */ 1248 fp = fdp->fd_ofiles[i]; 1249 fdp->fd_ofiles[i] = NULL; 1250 fdp->fd_ofileflags[i] = 0; 1251 if (i < fdp->fd_freefile) 1252 fdp->fd_freefile = i; 1253 (void) closef(fp, td); 1254 } 1255 } 1256 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1257 fdp->fd_lastfile--; 1258 } 1259 1260 /* 1261 * Close any files on exec? 1262 */ 1263 void 1264 fdcloseexec(struct proc *p) 1265 { 1266 struct thread *td = p->p_thread; 1267 struct filedesc *fdp = p->p_fd; 1268 int i; 1269 1270 /* Certain daemons might not have file descriptors. */ 1271 if (fdp == NULL) 1272 return; 1273 1274 /* 1275 * We cannot cache fd_ofiles or fd_ofileflags since operations 1276 * may block and rip them out from under us. 1277 */ 1278 for (i = 0; i <= fdp->fd_lastfile; i++) { 1279 if (fdp->fd_ofiles[i] != NULL && 1280 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1281 struct file *fp; 1282 1283 #if 0 1284 if (fdp->fd_ofileflags[i] & UF_MAPPED) 1285 (void) munmapfd(p, i); 1286 #endif 1287 if (i < fdp->fd_knlistsize) 1288 knote_fdclose(p, i); 1289 /* 1290 * NULL-out descriptor prior to close to avoid 1291 * a race while close blocks. 1292 */ 1293 fp = fdp->fd_ofiles[i]; 1294 fdp->fd_ofiles[i] = NULL; 1295 fdp->fd_ofileflags[i] = 0; 1296 if (i < fdp->fd_freefile) 1297 fdp->fd_freefile = i; 1298 (void) closef(fp, td); 1299 } 1300 } 1301 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1302 fdp->fd_lastfile--; 1303 } 1304 1305 /* 1306 * It is unsafe for set[ug]id processes to be started with file 1307 * descriptors 0..2 closed, as these descriptors are given implicit 1308 * significance in the Standard C library. fdcheckstd() will create a 1309 * descriptor referencing /dev/null for each of stdin, stdout, and 1310 * stderr that is not already open. 1311 */ 1312 int 1313 fdcheckstd(struct proc *p) 1314 { 1315 struct thread *td = p->p_thread; 1316 struct nameidata nd; 1317 struct filedesc *fdp; 1318 struct file *fp; 1319 register_t retval; 1320 int fd, i, error, flags, devnull; 1321 1322 fdp = p->p_fd; 1323 if (fdp == NULL) 1324 return (0); 1325 devnull = -1; 1326 error = 0; 1327 for (i = 0; i < 3; i++) { 1328 if (fdp->fd_ofiles[i] != NULL) 1329 continue; 1330 if (devnull < 0) { 1331 error = falloc(p, &fp, &fd); 1332 if (error != 0) 1333 break; 1334 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE, 1335 "/dev/null", td); 1336 flags = FREAD | FWRITE; 1337 error = vn_open(&nd, flags, 0); 1338 if (error != 0) { 1339 fdp->fd_ofiles[i] = NULL; 1340 fdrop(fp, td); 1341 break; 1342 } 1343 NDFREE(&nd, NDF_ONLY_PNBUF); 1344 fp->f_data = (caddr_t)nd.ni_vp; 1345 fp->f_flag = flags; 1346 fp->f_ops = &vnops; 1347 fp->f_type = DTYPE_VNODE; 1348 VOP_UNLOCK(nd.ni_vp, NULL, 0, td); 1349 devnull = fd; 1350 } else { 1351 error = kern_dup(DUP_FIXED, devnull, i, &retval); 1352 if (error != 0) 1353 break; 1354 } 1355 } 1356 return (error); 1357 } 1358 1359 /* 1360 * Internal form of close. 1361 * Decrement reference count on file structure. 1362 * Note: td and/or p may be NULL when closing a file 1363 * that was being passed in a message. 1364 */ 1365 int 1366 closef(struct file *fp, struct thread *td) 1367 { 1368 struct vnode *vp; 1369 struct flock lf; 1370 struct filedesc_to_leader *fdtol; 1371 struct proc *p; 1372 1373 if (fp == NULL) 1374 return (0); 1375 if (td == NULL) { 1376 td = curthread; 1377 p = NULL; /* allow no proc association */ 1378 } else { 1379 p = td->td_proc; /* can also be NULL */ 1380 } 1381 /* 1382 * POSIX record locking dictates that any close releases ALL 1383 * locks owned by this process. This is handled by setting 1384 * a flag in the unlock to free ONLY locks obeying POSIX 1385 * semantics, and not to free BSD-style file locks. 1386 * If the descriptor was in a message, POSIX-style locks 1387 * aren't passed with the descriptor. 1388 */ 1389 if (p != NULL && 1390 fp->f_type == DTYPE_VNODE) { 1391 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) { 1392 lf.l_whence = SEEK_SET; 1393 lf.l_start = 0; 1394 lf.l_len = 0; 1395 lf.l_type = F_UNLCK; 1396 vp = (struct vnode *)fp->f_data; 1397 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 1398 &lf, F_POSIX); 1399 } 1400 fdtol = p->p_fdtol; 1401 if (fdtol != NULL) { 1402 /* 1403 * Handle special case where file descriptor table 1404 * is shared between multiple process leaders. 1405 */ 1406 for (fdtol = fdtol->fdl_next; 1407 fdtol != p->p_fdtol; 1408 fdtol = fdtol->fdl_next) { 1409 if ((fdtol->fdl_leader->p_flag & 1410 P_ADVLOCK) == 0) 1411 continue; 1412 fdtol->fdl_holdcount++; 1413 lf.l_whence = SEEK_SET; 1414 lf.l_start = 0; 1415 lf.l_len = 0; 1416 lf.l_type = F_UNLCK; 1417 vp = (struct vnode *)fp->f_data; 1418 (void) VOP_ADVLOCK(vp, 1419 (caddr_t)p->p_leader, 1420 F_UNLCK, &lf, F_POSIX); 1421 fdtol->fdl_holdcount--; 1422 if (fdtol->fdl_holdcount == 0 && 1423 fdtol->fdl_wakeup != 0) { 1424 fdtol->fdl_wakeup = 0; 1425 wakeup(fdtol); 1426 } 1427 } 1428 } 1429 } 1430 return (fdrop(fp, td)); 1431 } 1432 1433 int 1434 fdrop(struct file *fp, struct thread *td) 1435 { 1436 struct flock lf; 1437 struct vnode *vp; 1438 int error; 1439 1440 if (--fp->f_count > 0) 1441 return (0); 1442 if (fp->f_count < 0) 1443 panic("fdrop: count < 0"); 1444 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 1445 lf.l_whence = SEEK_SET; 1446 lf.l_start = 0; 1447 lf.l_len = 0; 1448 lf.l_type = F_UNLCK; 1449 vp = (struct vnode *)fp->f_data; 1450 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 1451 } 1452 if (fp->f_ops != &badfileops) 1453 error = fo_close(fp, td); 1454 else 1455 error = 0; 1456 ffree(fp); 1457 return (error); 1458 } 1459 1460 /* 1461 * Apply an advisory lock on a file descriptor. 1462 * 1463 * Just attempt to get a record lock of the requested type on 1464 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 1465 */ 1466 /* ARGSUSED */ 1467 int 1468 flock(struct flock_args *uap) 1469 { 1470 struct proc *p = curproc; 1471 struct filedesc *fdp = p->p_fd; 1472 struct file *fp; 1473 struct vnode *vp; 1474 struct flock lf; 1475 1476 if ((unsigned)uap->fd >= fdp->fd_nfiles || 1477 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 1478 return (EBADF); 1479 if (fp->f_type != DTYPE_VNODE) 1480 return (EOPNOTSUPP); 1481 vp = (struct vnode *)fp->f_data; 1482 lf.l_whence = SEEK_SET; 1483 lf.l_start = 0; 1484 lf.l_len = 0; 1485 if (uap->how & LOCK_UN) { 1486 lf.l_type = F_UNLCK; 1487 fp->f_flag &= ~FHASLOCK; 1488 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK)); 1489 } 1490 if (uap->how & LOCK_EX) 1491 lf.l_type = F_WRLCK; 1492 else if (uap->how & LOCK_SH) 1493 lf.l_type = F_RDLCK; 1494 else 1495 return (EBADF); 1496 fp->f_flag |= FHASLOCK; 1497 if (uap->how & LOCK_NB) 1498 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK)); 1499 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT)); 1500 } 1501 1502 /* 1503 * File Descriptor pseudo-device driver (/dev/fd/). 1504 * 1505 * Opening minor device N dup()s the file (if any) connected to file 1506 * descriptor N belonging to the calling process. Note that this driver 1507 * consists of only the ``open()'' routine, because all subsequent 1508 * references to this file will be direct to the other driver. 1509 */ 1510 /* ARGSUSED */ 1511 static int 1512 fdopen(dev_t dev, int mode, int type, struct thread *td) 1513 { 1514 KKASSERT(td->td_proc != NULL); 1515 1516 /* 1517 * XXX Kludge: set curproc->p_dupfd to contain the value of the 1518 * the file descriptor being sought for duplication. The error 1519 * return ensures that the vnode for this device will be released 1520 * by vn_open. Open will detect this special error and take the 1521 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 1522 * will simply report the error. 1523 */ 1524 td->td_proc->p_dupfd = minor(dev); 1525 return (ENODEV); 1526 } 1527 1528 /* 1529 * Duplicate the specified descriptor to a free descriptor. 1530 */ 1531 int 1532 dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode, int error) 1533 { 1534 struct file *wfp; 1535 struct file *fp; 1536 1537 /* 1538 * If the to-be-dup'd fd number is greater than the allowed number 1539 * of file descriptors, or the fd to be dup'd has already been 1540 * closed, then reject. 1541 */ 1542 if ((u_int)dfd >= fdp->fd_nfiles || 1543 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 1544 return (EBADF); 1545 } 1546 1547 /* 1548 * There are two cases of interest here. 1549 * 1550 * For ENODEV simply dup (dfd) to file descriptor 1551 * (indx) and return. 1552 * 1553 * For ENXIO steal away the file structure from (dfd) and 1554 * store it in (indx). (dfd) is effectively closed by 1555 * this operation. 1556 * 1557 * Any other error code is just returned. 1558 */ 1559 switch (error) { 1560 case ENODEV: 1561 /* 1562 * Check that the mode the file is being opened for is a 1563 * subset of the mode of the existing descriptor. 1564 */ 1565 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) 1566 return (EACCES); 1567 fp = fdp->fd_ofiles[indx]; 1568 #if 0 1569 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1570 (void) munmapfd(p, indx); 1571 #endif 1572 fdp->fd_ofiles[indx] = wfp; 1573 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1574 fhold(wfp); 1575 if (indx > fdp->fd_lastfile) 1576 fdp->fd_lastfile = indx; 1577 /* 1578 * we now own the reference to fp that the ofiles[] array 1579 * used to own. Release it. 1580 */ 1581 if (fp) 1582 fdrop(fp, curthread); 1583 return (0); 1584 1585 case ENXIO: 1586 /* 1587 * Steal away the file pointer from dfd, and stuff it into indx. 1588 */ 1589 fp = fdp->fd_ofiles[indx]; 1590 #if 0 1591 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1592 (void) munmapfd(p, indx); 1593 #endif 1594 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 1595 fdp->fd_ofiles[dfd] = NULL; 1596 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1597 fdp->fd_ofileflags[dfd] = 0; 1598 1599 /* 1600 * we now own the reference to fp that the ofiles[] array 1601 * used to own. Release it. 1602 */ 1603 if (fp) 1604 fdrop(fp, curthread); 1605 /* 1606 * Complete the clean up of the filedesc structure by 1607 * recomputing the various hints. 1608 */ 1609 if (indx > fdp->fd_lastfile) { 1610 fdp->fd_lastfile = indx; 1611 } else { 1612 while (fdp->fd_lastfile > 0 && 1613 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) { 1614 fdp->fd_lastfile--; 1615 } 1616 if (dfd < fdp->fd_freefile) 1617 fdp->fd_freefile = dfd; 1618 } 1619 return (0); 1620 1621 default: 1622 return (error); 1623 } 1624 /* NOTREACHED */ 1625 } 1626 1627 1628 struct filedesc_to_leader * 1629 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 1630 struct proc *leader) 1631 { 1632 struct filedesc_to_leader *fdtol; 1633 1634 fdtol = malloc(sizeof(struct filedesc_to_leader), 1635 M_FILEDESC_TO_LEADER, M_WAITOK); 1636 fdtol->fdl_refcount = 1; 1637 fdtol->fdl_holdcount = 0; 1638 fdtol->fdl_wakeup = 0; 1639 fdtol->fdl_leader = leader; 1640 if (old != NULL) { 1641 fdtol->fdl_next = old->fdl_next; 1642 fdtol->fdl_prev = old; 1643 old->fdl_next = fdtol; 1644 fdtol->fdl_next->fdl_prev = fdtol; 1645 } else { 1646 fdtol->fdl_next = fdtol; 1647 fdtol->fdl_prev = fdtol; 1648 } 1649 return fdtol; 1650 } 1651 1652 /* 1653 * Get file structures. 1654 */ 1655 static int 1656 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 1657 { 1658 int error; 1659 struct file *fp; 1660 1661 if (!req->oldptr) { 1662 /* 1663 * overestimate by 10 files 1664 */ 1665 return (SYSCTL_OUT(req, 0, sizeof(filehead) + 1666 (nfiles + 10) * sizeof(struct file))); 1667 } 1668 1669 error = SYSCTL_OUT(req, (caddr_t)&filehead, sizeof(filehead)); 1670 if (error) 1671 return (error); 1672 1673 /* 1674 * followed by an array of file structures 1675 */ 1676 LIST_FOREACH(fp, &filehead, f_list) { 1677 error = SYSCTL_OUT(req, (caddr_t)fp, sizeof (struct file)); 1678 if (error) 1679 return (error); 1680 } 1681 return (0); 1682 } 1683 1684 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 1685 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 1686 1687 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 1688 &maxfilesperproc, 0, "Maximum files allowed open per process"); 1689 1690 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 1691 &maxfiles, 0, "Maximum number of files"); 1692 1693 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 1694 &maxfilesrootres, 0, "Descriptors reserved for root use"); 1695 1696 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 1697 &nfiles, 0, "System-wide number of open files"); 1698 1699 static void 1700 fildesc_drvinit(void *unused) 1701 { 1702 int fd; 1703 1704 cdevsw_add(&fildesc_cdevsw, 0, 0); 1705 for (fd = 0; fd < NUMFDESC; fd++) { 1706 make_dev(&fildesc_cdevsw, fd, 1707 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 1708 } 1709 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 1710 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 1711 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 1712 } 1713 1714 struct fileops badfileops = { 1715 NULL, /* port */ 1716 NULL, /* clone */ 1717 badfo_readwrite, 1718 badfo_readwrite, 1719 badfo_ioctl, 1720 badfo_poll, 1721 badfo_kqfilter, 1722 badfo_stat, 1723 badfo_close 1724 }; 1725 1726 static int 1727 badfo_readwrite( 1728 struct file *fp, 1729 struct uio *uio, 1730 struct ucred *cred, 1731 int flags, 1732 struct thread *td 1733 ) { 1734 return (EBADF); 1735 } 1736 1737 static int 1738 badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td) 1739 { 1740 return (EBADF); 1741 } 1742 1743 static int 1744 badfo_poll(struct file *fp, int events, struct ucred *cred, struct thread *td) 1745 { 1746 return (0); 1747 } 1748 1749 static int 1750 badfo_kqfilter(struct file *fp, struct knote *kn) 1751 { 1752 return (0); 1753 } 1754 1755 static int 1756 badfo_stat(struct file *fp, struct stat *sb, struct thread *td) 1757 { 1758 return (EBADF); 1759 } 1760 1761 static int 1762 badfo_close(struct file *fp, struct thread *td) 1763 { 1764 return (EBADF); 1765 } 1766 1767 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 1768 fildesc_drvinit,NULL) 1769