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 1.42 2005/06/06 15:02:27 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/nlookup.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 #include <sys/kcore.h> 64 #include <sys/kinfo.h> 65 66 #include <vm/vm.h> 67 #include <vm/vm_extern.h> 68 69 #include <sys/thread2.h> 70 #include <sys/file2.h> 71 72 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 73 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 74 "file desc to leader structures"); 75 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 76 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 77 78 static d_open_t fdopen; 79 #define NUMFDESC 64 80 81 #define CDEV_MAJOR 22 82 static struct cdevsw fildesc_cdevsw = { 83 /* name */ "FD", 84 /* maj */ CDEV_MAJOR, 85 /* flags */ 0, 86 /* port */ NULL, 87 /* clone */ NULL, 88 89 /* open */ fdopen, 90 /* close */ noclose, 91 /* read */ noread, 92 /* write */ nowrite, 93 /* ioctl */ noioctl, 94 /* poll */ nopoll, 95 /* mmap */ nommap, 96 /* strategy */ nostrategy, 97 /* dump */ nodump, 98 /* psize */ nopsize 99 }; 100 101 static int badfo_readwrite (struct file *fp, struct uio *uio, 102 struct ucred *cred, int flags, struct thread *td); 103 static int badfo_ioctl (struct file *fp, u_long com, caddr_t data, 104 struct thread *td); 105 static int badfo_poll (struct file *fp, int events, 106 struct ucred *cred, struct thread *td); 107 static int badfo_kqfilter (struct file *fp, struct knote *kn); 108 static int badfo_stat (struct file *fp, struct stat *sb, struct thread *td); 109 static int badfo_close (struct file *fp, struct thread *td); 110 111 /* 112 * Descriptor management. 113 */ 114 struct filelist filehead; /* head of list of open files */ 115 int nfiles; /* actual number of open files */ 116 extern int cmask; 117 118 /* 119 * System calls on descriptors. 120 */ 121 /* ARGSUSED */ 122 int 123 getdtablesize(struct getdtablesize_args *uap) 124 { 125 struct proc *p = curproc; 126 127 uap->sysmsg_result = 128 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 129 return (0); 130 } 131 132 /* 133 * Duplicate a file descriptor to a particular value. 134 * 135 * note: keep in mind that a potential race condition exists when closing 136 * descriptors from a shared descriptor table (via rfork). 137 */ 138 /* ARGSUSED */ 139 int 140 dup2(struct dup2_args *uap) 141 { 142 int error; 143 144 error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds); 145 146 return (error); 147 } 148 149 /* 150 * Duplicate a file descriptor. 151 */ 152 /* ARGSUSED */ 153 int 154 dup(struct dup_args *uap) 155 { 156 int error; 157 158 error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds); 159 160 return (error); 161 } 162 163 int 164 kern_fcntl(int fd, int cmd, union fcntl_dat *dat) 165 { 166 struct thread *td = curthread; 167 struct proc *p = td->td_proc; 168 struct filedesc *fdp = p->p_fd; 169 struct file *fp; 170 char *pop; 171 struct vnode *vp; 172 u_int newmin; 173 int tmp, error, flg = F_POSIX; 174 175 KKASSERT(p); 176 177 if ((unsigned)fd >= fdp->fd_nfiles || 178 (fp = fdp->fd_ofiles[fd]) == NULL) 179 return (EBADF); 180 pop = &fdp->fd_ofileflags[fd]; 181 182 switch (cmd) { 183 case F_DUPFD: 184 newmin = dat->fc_fd; 185 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 186 newmin > maxfilesperproc) 187 return (EINVAL); 188 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); 189 return (error); 190 191 case F_GETFD: 192 dat->fc_cloexec = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 193 return (0); 194 195 case F_SETFD: 196 *pop = (*pop &~ UF_EXCLOSE) | 197 (dat->fc_cloexec & FD_CLOEXEC ? UF_EXCLOSE : 0); 198 return (0); 199 200 case F_GETFL: 201 dat->fc_flags = OFLAGS(fp->f_flag); 202 return (0); 203 204 case F_SETFL: 205 fhold(fp); 206 fp->f_flag &= ~FCNTLFLAGS; 207 fp->f_flag |= FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 208 tmp = fp->f_flag & FNONBLOCK; 209 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td); 210 if (error) { 211 fdrop(fp, td); 212 return (error); 213 } 214 tmp = fp->f_flag & FASYNC; 215 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, td); 216 if (!error) { 217 fdrop(fp, td); 218 return (0); 219 } 220 fp->f_flag &= ~FNONBLOCK; 221 tmp = 0; 222 fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td); 223 fdrop(fp, td); 224 return (error); 225 226 case F_GETOWN: 227 fhold(fp); 228 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, td); 229 fdrop(fp, td); 230 return(error); 231 232 case F_SETOWN: 233 fhold(fp); 234 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, td); 235 fdrop(fp, td); 236 return(error); 237 238 case F_SETLKW: 239 flg |= F_WAIT; 240 /* Fall into F_SETLK */ 241 242 case F_SETLK: 243 if (fp->f_type != DTYPE_VNODE) 244 return (EBADF); 245 vp = (struct vnode *)fp->f_data; 246 247 /* 248 * copyin/lockop may block 249 */ 250 fhold(fp); 251 if (dat->fc_flock.l_whence == SEEK_CUR) 252 dat->fc_flock.l_start += fp->f_offset; 253 254 switch (dat->fc_flock.l_type) { 255 case F_RDLCK: 256 if ((fp->f_flag & FREAD) == 0) { 257 error = EBADF; 258 break; 259 } 260 p->p_leader->p_flag |= P_ADVLOCK; 261 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 262 &dat->fc_flock, flg); 263 break; 264 case F_WRLCK: 265 if ((fp->f_flag & FWRITE) == 0) { 266 error = EBADF; 267 break; 268 } 269 p->p_leader->p_flag |= P_ADVLOCK; 270 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 271 &dat->fc_flock, flg); 272 break; 273 case F_UNLCK: 274 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 275 &dat->fc_flock, F_POSIX); 276 break; 277 default: 278 error = EINVAL; 279 break; 280 } 281 /* Check for race with close */ 282 if ((unsigned) fd >= fdp->fd_nfiles || 283 fp != fdp->fd_ofiles[fd]) { 284 dat->fc_flock.l_whence = SEEK_SET; 285 dat->fc_flock.l_start = 0; 286 dat->fc_flock.l_len = 0; 287 dat->fc_flock.l_type = F_UNLCK; 288 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 289 F_UNLCK, &dat->fc_flock, F_POSIX); 290 } 291 fdrop(fp, td); 292 return(error); 293 294 case F_GETLK: 295 if (fp->f_type != DTYPE_VNODE) 296 return (EBADF); 297 vp = (struct vnode *)fp->f_data; 298 /* 299 * copyin/lockop may block 300 */ 301 fhold(fp); 302 if (dat->fc_flock.l_type != F_RDLCK && 303 dat->fc_flock.l_type != F_WRLCK && 304 dat->fc_flock.l_type != F_UNLCK) { 305 fdrop(fp, td); 306 return (EINVAL); 307 } 308 if (dat->fc_flock.l_whence == SEEK_CUR) 309 dat->fc_flock.l_start += fp->f_offset; 310 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 311 &dat->fc_flock, F_POSIX); 312 fdrop(fp, td); 313 return(error); 314 default: 315 return (EINVAL); 316 } 317 /* NOTREACHED */ 318 } 319 320 /* 321 * The file control system call. 322 */ 323 int 324 fcntl(struct fcntl_args *uap) 325 { 326 union fcntl_dat dat; 327 int error; 328 329 switch (uap->cmd) { 330 case F_DUPFD: 331 dat.fc_fd = uap->arg; 332 break; 333 case F_SETFD: 334 dat.fc_cloexec = uap->arg; 335 break; 336 case F_SETFL: 337 dat.fc_flags = uap->arg; 338 break; 339 case F_SETOWN: 340 dat.fc_owner = uap->arg; 341 break; 342 case F_SETLKW: 343 case F_SETLK: 344 case F_GETLK: 345 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 346 sizeof(struct flock)); 347 if (error) 348 return (error); 349 break; 350 } 351 352 error = kern_fcntl(uap->fd, uap->cmd, &dat); 353 354 if (error == 0) { 355 switch (uap->cmd) { 356 case F_DUPFD: 357 uap->sysmsg_result = dat.fc_fd; 358 break; 359 case F_GETFD: 360 uap->sysmsg_result = dat.fc_cloexec; 361 break; 362 case F_GETFL: 363 uap->sysmsg_result = dat.fc_flags; 364 break; 365 case F_GETOWN: 366 uap->sysmsg_result = dat.fc_owner; 367 case F_GETLK: 368 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 369 sizeof(struct flock)); 370 break; 371 } 372 } 373 374 return (error); 375 } 376 377 /* 378 * Common code for dup, dup2, and fcntl(F_DUPFD). 379 * 380 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells 381 * kern_dup() to destructively dup over an existing file descriptor if new 382 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest 383 * unused file descriptor that is greater than or equal to new. 384 */ 385 int 386 kern_dup(enum dup_type type, int old, int new, int *res) 387 { 388 struct thread *td = curthread; 389 struct proc *p = td->td_proc; 390 struct filedesc *fdp = p->p_fd; 391 struct file *fp; 392 struct file *delfp; 393 int holdleaders; 394 int error, newfd; 395 396 /* 397 * Verify that we have a valid descriptor to dup from and 398 * possibly to dup to. 399 */ 400 if (old < 0 || new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 401 new >= maxfilesperproc) 402 return (EBADF); 403 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) 404 return (EBADF); 405 if (type == DUP_FIXED && old == new) { 406 *res = new; 407 return (0); 408 } 409 fp = fdp->fd_ofiles[old]; 410 fhold(fp); 411 412 /* 413 * Expand the table for the new descriptor if needed. This may 414 * block and drop and reacquire the fidedesc lock. 415 */ 416 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) { 417 error = fdalloc(p, new, &newfd); 418 if (error) { 419 fdrop(fp, td); 420 return (error); 421 } 422 } 423 if (type == DUP_VARIABLE) 424 new = newfd; 425 426 /* 427 * If the old file changed out from under us then treat it as a 428 * bad file descriptor. Userland should do its own locking to 429 * avoid this case. 430 */ 431 if (fdp->fd_ofiles[old] != fp) { 432 if (fdp->fd_ofiles[new] == NULL) { 433 if (new < fdp->fd_freefile) 434 fdp->fd_freefile = new; 435 while (fdp->fd_lastfile > 0 && 436 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 437 fdp->fd_lastfile--; 438 } 439 fdrop(fp, td); 440 return (EBADF); 441 } 442 KASSERT(old != new, ("new fd is same as old")); 443 444 /* 445 * Save info on the descriptor being overwritten. We have 446 * to do the unmap now, but we cannot close it without 447 * introducing an ownership race for the slot. 448 */ 449 delfp = fdp->fd_ofiles[new]; 450 if (delfp != NULL && p->p_fdtol != NULL) { 451 /* 452 * Ask fdfree() to sleep to ensure that all relevant 453 * process leaders can be traversed in closef(). 454 */ 455 fdp->fd_holdleaderscount++; 456 holdleaders = 1; 457 } else 458 holdleaders = 0; 459 KASSERT(delfp == NULL || type == DUP_FIXED, 460 ("dup() picked an open file")); 461 #if 0 462 if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED)) 463 (void) munmapfd(p, new); 464 #endif 465 466 /* 467 * Duplicate the source descriptor, update lastfile 468 */ 469 fdp->fd_ofiles[new] = fp; 470 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 471 if (new > fdp->fd_lastfile) 472 fdp->fd_lastfile = new; 473 *res = new; 474 475 /* 476 * If we dup'd over a valid file, we now own the reference to it 477 * and must dispose of it using closef() semantics (as if a 478 * close() were performed on it). 479 */ 480 if (delfp) { 481 (void) closef(delfp, td); 482 if (holdleaders) { 483 fdp->fd_holdleaderscount--; 484 if (fdp->fd_holdleaderscount == 0 && 485 fdp->fd_holdleaderswakeup != 0) { 486 fdp->fd_holdleaderswakeup = 0; 487 wakeup(&fdp->fd_holdleaderscount); 488 } 489 } 490 } 491 return (0); 492 } 493 494 /* 495 * If sigio is on the list associated with a process or process group, 496 * disable signalling from the device, remove sigio from the list and 497 * free sigio. 498 */ 499 void 500 funsetown(struct sigio *sigio) 501 { 502 if (sigio == NULL) 503 return; 504 crit_enter(); 505 *(sigio->sio_myref) = NULL; 506 crit_exit(); 507 if (sigio->sio_pgid < 0) { 508 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 509 sigio, sio_pgsigio); 510 } else /* if ((*sigiop)->sio_pgid > 0) */ { 511 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 512 sigio, sio_pgsigio); 513 } 514 crfree(sigio->sio_ucred); 515 free(sigio, M_SIGIO); 516 } 517 518 /* Free a list of sigio structures. */ 519 void 520 funsetownlst(struct sigiolst *sigiolst) 521 { 522 struct sigio *sigio; 523 524 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 525 funsetown(sigio); 526 } 527 528 /* 529 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 530 * 531 * After permission checking, add a sigio structure to the sigio list for 532 * the process or process group. 533 */ 534 int 535 fsetown(pid_t pgid, struct sigio **sigiop) 536 { 537 struct proc *proc; 538 struct pgrp *pgrp; 539 struct sigio *sigio; 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 crit_enter(); 595 *sigiop = sigio; 596 crit_exit(); 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 many file descriptors. 611 */ 612 /* ARGSUSED */ 613 614 int 615 closefrom(struct closefrom_args *uap) 616 { 617 return(kern_closefrom(uap->fd)); 618 } 619 620 int 621 kern_closefrom(int fd) 622 { 623 struct thread *td = curthread; 624 struct proc *p = td->td_proc; 625 struct filedesc *fdp; 626 627 KKASSERT(p); 628 fdp = p->p_fd; 629 630 if (fd < 0 || fd > fdp->fd_lastfile) 631 return (0); 632 633 do { 634 if (kern_close(fdp->fd_lastfile) == EINTR) 635 return (EINTR); 636 } while (fdp->fd_lastfile > fd); 637 638 return (0); 639 } 640 641 /* 642 * Close a file descriptor. 643 */ 644 /* ARGSUSED */ 645 646 int 647 close(struct close_args *uap) 648 { 649 return(kern_close(uap->fd)); 650 } 651 652 int 653 kern_close(int fd) 654 { 655 struct thread *td = curthread; 656 struct proc *p = td->td_proc; 657 struct filedesc *fdp; 658 struct file *fp; 659 int error; 660 int holdleaders; 661 662 KKASSERT(p); 663 fdp = p->p_fd; 664 665 if ((unsigned)fd >= fdp->fd_nfiles || 666 (fp = fdp->fd_ofiles[fd]) == NULL) 667 return (EBADF); 668 #if 0 669 if (fdp->fd_ofileflags[fd] & UF_MAPPED) 670 (void) munmapfd(p, fd); 671 #endif 672 fdp->fd_ofiles[fd] = NULL; 673 fdp->fd_ofileflags[fd] = 0; 674 holdleaders = 0; 675 if (p->p_fdtol != NULL) { 676 /* 677 * Ask fdfree() to sleep to ensure that all relevant 678 * process leaders can be traversed in closef(). 679 */ 680 fdp->fd_holdleaderscount++; 681 holdleaders = 1; 682 } 683 684 /* 685 * we now hold the fp reference that used to be owned by the descriptor 686 * array. 687 */ 688 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 689 fdp->fd_lastfile--; 690 if (fd < fdp->fd_freefile) 691 fdp->fd_freefile = fd; 692 if (fd < fdp->fd_knlistsize) 693 knote_fdclose(p, fd); 694 error = closef(fp, td); 695 if (holdleaders) { 696 fdp->fd_holdleaderscount--; 697 if (fdp->fd_holdleaderscount == 0 && 698 fdp->fd_holdleaderswakeup != 0) { 699 fdp->fd_holdleaderswakeup = 0; 700 wakeup(&fdp->fd_holdleaderscount); 701 } 702 } 703 return (error); 704 } 705 706 int 707 kern_fstat(int fd, struct stat *ub) 708 { 709 struct thread *td = curthread; 710 struct proc *p = td->td_proc; 711 struct filedesc *fdp; 712 struct file *fp; 713 int error; 714 715 KKASSERT(p); 716 717 fdp = p->p_fd; 718 if ((unsigned)fd >= fdp->fd_nfiles || 719 (fp = fdp->fd_ofiles[fd]) == NULL) 720 return (EBADF); 721 fhold(fp); 722 error = fo_stat(fp, ub, td); 723 fdrop(fp, td); 724 725 return (error); 726 } 727 728 /* 729 * Return status information about a file descriptor. 730 */ 731 int 732 fstat(struct fstat_args *uap) 733 { 734 struct stat st; 735 int error; 736 737 error = kern_fstat(uap->fd, &st); 738 739 if (error == 0) 740 error = copyout(&st, uap->sb, sizeof(st)); 741 return (error); 742 } 743 744 /* 745 * XXX: This is for source compatibility with NetBSD. Probably doesn't 746 * belong here. 747 */ 748 int 749 nfstat(struct nfstat_args *uap) 750 { 751 struct stat st; 752 struct nstat nst; 753 int error; 754 755 error = kern_fstat(uap->fd, &st); 756 757 if (error == 0) { 758 cvtnstat(&st, &nst); 759 error = copyout(&nst, uap->sb, sizeof (nst)); 760 } 761 return (error); 762 } 763 764 /* 765 * Return pathconf information about a file descriptor. 766 */ 767 /* ARGSUSED */ 768 int 769 fpathconf(struct fpathconf_args *uap) 770 { 771 struct thread *td = curthread; 772 struct proc *p = td->td_proc; 773 struct filedesc *fdp; 774 struct file *fp; 775 struct vnode *vp; 776 int error = 0; 777 778 KKASSERT(p); 779 fdp = p->p_fd; 780 if ((unsigned)uap->fd >= fdp->fd_nfiles || 781 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 782 return (EBADF); 783 784 fhold(fp); 785 786 switch (fp->f_type) { 787 case DTYPE_PIPE: 788 case DTYPE_SOCKET: 789 if (uap->name != _PC_PIPE_BUF) { 790 error = EINVAL; 791 } else { 792 uap->sysmsg_result = PIPE_BUF; 793 error = 0; 794 } 795 break; 796 case DTYPE_FIFO: 797 case DTYPE_VNODE: 798 vp = (struct vnode *)fp->f_data; 799 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds); 800 break; 801 default: 802 error = EOPNOTSUPP; 803 break; 804 } 805 fdrop(fp, td); 806 return(error); 807 } 808 809 /* 810 * Allocate a file descriptor for the process. 811 */ 812 static int fdexpand; 813 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, ""); 814 815 int 816 fdalloc(struct proc *p, int want, int *result) 817 { 818 struct filedesc *fdp = p->p_fd; 819 int i; 820 int lim, last, nfiles; 821 struct file **newofile; 822 char *newofileflags; 823 824 /* 825 * Search for a free descriptor starting at the higher 826 * of want or fd_freefile. If that fails, consider 827 * expanding the ofile array. 828 */ 829 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 830 for (;;) { 831 last = min(fdp->fd_nfiles, lim); 832 if ((i = want) < fdp->fd_freefile) 833 i = fdp->fd_freefile; 834 for (; i < last; i++) { 835 if (fdp->fd_ofiles[i] == NULL) { 836 fdp->fd_ofileflags[i] = 0; 837 if (i > fdp->fd_lastfile) 838 fdp->fd_lastfile = i; 839 if (want <= fdp->fd_freefile) 840 fdp->fd_freefile = i; 841 *result = i; 842 return (0); 843 } 844 } 845 846 /* 847 * No space in current array. Expand? 848 */ 849 if (fdp->fd_nfiles >= lim) 850 return (EMFILE); 851 if (fdp->fd_nfiles < NDEXTENT) 852 nfiles = NDEXTENT; 853 else 854 nfiles = 2 * fdp->fd_nfiles; 855 newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK); 856 857 /* 858 * deal with file-table extend race that might have occured 859 * when malloc was blocked. 860 */ 861 if (fdp->fd_nfiles >= nfiles) { 862 free(newofile, M_FILEDESC); 863 continue; 864 } 865 newofileflags = (char *) &newofile[nfiles]; 866 /* 867 * Copy the existing ofile and ofileflags arrays 868 * and zero the new portion of each array. 869 */ 870 bcopy(fdp->fd_ofiles, newofile, 871 (i = sizeof(struct file *) * fdp->fd_nfiles)); 872 bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i); 873 bcopy(fdp->fd_ofileflags, newofileflags, 874 (i = sizeof(char) * fdp->fd_nfiles)); 875 bzero(newofileflags + i, nfiles * sizeof(char) - i); 876 if (fdp->fd_nfiles > NDFILE) 877 free(fdp->fd_ofiles, M_FILEDESC); 878 fdp->fd_ofiles = newofile; 879 fdp->fd_ofileflags = newofileflags; 880 fdp->fd_nfiles = nfiles; 881 fdexpand++; 882 } 883 return (0); 884 } 885 886 /* 887 * Check to see whether n user file descriptors 888 * are available to the process p. 889 */ 890 int 891 fdavail(struct proc *p, int n) 892 { 893 struct filedesc *fdp = p->p_fd; 894 struct file **fpp; 895 int i, lim, last; 896 897 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 898 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 899 return (1); 900 901 last = min(fdp->fd_nfiles, lim); 902 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 903 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 904 if (*fpp == NULL && --n <= 0) 905 return (1); 906 } 907 return (0); 908 } 909 910 /* 911 * falloc: 912 * Create a new open file structure and allocate a file decriptor 913 * for the process that refers to it. If p is NULL, no descriptor 914 * is allocated and the file pointer is returned unassociated with 915 * any process. resultfd is only used if p is not NULL and may 916 * separately be NULL indicating that you don't need the returned fd. 917 * 918 * A held file pointer is returned. If a descriptor has been allocated 919 * an additional hold on the fp will be made due to the fd_ofiles[] 920 * reference. 921 */ 922 int 923 falloc(struct proc *p, struct file **resultfp, int *resultfd) 924 { 925 static struct timeval lastfail; 926 static int curfail; 927 struct file *fp; 928 int error; 929 930 fp = NULL; 931 932 /* 933 * Handle filetable full issues and root overfill. 934 */ 935 if (nfiles >= maxfiles - maxfilesrootres && 936 ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) { 937 if (ppsratecheck(&lastfail, &curfail, 1)) { 938 printf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n", 939 (p ? p->p_ucred->cr_ruid : -1)); 940 } 941 error = ENFILE; 942 goto done; 943 } 944 945 /* 946 * Allocate a new file descriptor. 947 */ 948 nfiles++; 949 fp = malloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 950 fp->f_count = 1; 951 fp->f_ops = &badfileops; 952 fp->f_seqcount = 1; 953 if (p) 954 fp->f_cred = crhold(p->p_ucred); 955 else 956 fp->f_cred = crhold(proc0.p_ucred); 957 LIST_INSERT_HEAD(&filehead, fp, f_list); 958 if (resultfd) { 959 if ((error = fsetfd(p, fp, resultfd)) != 0) { 960 fdrop(fp, p->p_thread); 961 fp = NULL; 962 } 963 } else { 964 error = 0; 965 } 966 done: 967 *resultfp = fp; 968 return (error); 969 } 970 971 /* 972 * Associate a file pointer with a file descriptor. On success the fp 973 * will have an additional ref representing the fd_ofiles[] association. 974 */ 975 int 976 fsetfd(struct proc *p, struct file *fp, int *resultfd) 977 { 978 int i; 979 int error; 980 981 KKASSERT(p); 982 983 i = -1; 984 if ((error = fdalloc(p, 0, &i)) == 0) { 985 fhold(fp); 986 p->p_fd->fd_ofiles[i] = fp; 987 } 988 *resultfd = i; 989 return (0); 990 } 991 992 void 993 fsetcred(struct file *fp, struct ucred *cr) 994 { 995 crhold(cr); 996 crfree(fp->f_cred); 997 fp->f_cred = cr; 998 } 999 1000 /* 1001 * Free a file descriptor. 1002 */ 1003 void 1004 ffree(struct file *fp) 1005 { 1006 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 1007 LIST_REMOVE(fp, f_list); 1008 crfree(fp->f_cred); 1009 if (fp->f_ncp) { 1010 cache_drop(fp->f_ncp); 1011 fp->f_ncp = NULL; 1012 } 1013 nfiles--; 1014 free(fp, M_FILE); 1015 } 1016 1017 /* 1018 * Build a new filedesc structure. 1019 */ 1020 struct filedesc * 1021 fdinit(struct proc *p) 1022 { 1023 struct filedesc0 *newfdp; 1024 struct filedesc *fdp = p->p_fd; 1025 1026 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK|M_ZERO); 1027 if (fdp->fd_cdir) { 1028 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1029 vref(newfdp->fd_fd.fd_cdir); 1030 newfdp->fd_fd.fd_ncdir = cache_hold(fdp->fd_ncdir); 1031 } 1032 1033 /* 1034 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 1035 * proc0, but should unconditionally exist in other processes. 1036 */ 1037 if (fdp->fd_rdir) { 1038 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1039 vref(newfdp->fd_fd.fd_rdir); 1040 newfdp->fd_fd.fd_nrdir = cache_hold(fdp->fd_nrdir); 1041 } 1042 if (fdp->fd_jdir) { 1043 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1044 vref(newfdp->fd_fd.fd_jdir); 1045 newfdp->fd_fd.fd_njdir = cache_hold(fdp->fd_njdir); 1046 } 1047 1048 /* Create the file descriptor table. */ 1049 newfdp->fd_fd.fd_refcnt = 1; 1050 newfdp->fd_fd.fd_cmask = cmask; 1051 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1052 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1053 newfdp->fd_fd.fd_nfiles = NDFILE; 1054 newfdp->fd_fd.fd_knlistsize = -1; 1055 1056 return (&newfdp->fd_fd); 1057 } 1058 1059 /* 1060 * Share a filedesc structure. 1061 */ 1062 struct filedesc * 1063 fdshare(struct proc *p) 1064 { 1065 p->p_fd->fd_refcnt++; 1066 return (p->p_fd); 1067 } 1068 1069 /* 1070 * Copy a filedesc structure. 1071 */ 1072 struct filedesc * 1073 fdcopy(struct proc *p) 1074 { 1075 struct filedesc *newfdp, *fdp = p->p_fd; 1076 struct file **fpp; 1077 int i; 1078 1079 /* Certain daemons might not have file descriptors. */ 1080 if (fdp == NULL) 1081 return (NULL); 1082 1083 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK); 1084 bcopy(fdp, newfdp, sizeof(struct filedesc)); 1085 if (newfdp->fd_cdir) { 1086 vref(newfdp->fd_cdir); 1087 newfdp->fd_ncdir = cache_hold(newfdp->fd_ncdir); 1088 } 1089 /* 1090 * We must check for fd_rdir here, at least for now because 1091 * the init process is created before we have access to the 1092 * rootvode to take a reference to it. 1093 */ 1094 if (newfdp->fd_rdir) { 1095 vref(newfdp->fd_rdir); 1096 newfdp->fd_nrdir = cache_hold(newfdp->fd_nrdir); 1097 } 1098 if (newfdp->fd_jdir) { 1099 vref(newfdp->fd_jdir); 1100 newfdp->fd_njdir = cache_hold(newfdp->fd_njdir); 1101 } 1102 newfdp->fd_refcnt = 1; 1103 1104 /* 1105 * If the number of open files fits in the internal arrays 1106 * of the open file structure, use them, otherwise allocate 1107 * additional memory for the number of descriptors currently 1108 * in use. 1109 */ 1110 if (newfdp->fd_lastfile < NDFILE) { 1111 newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles; 1112 newfdp->fd_ofileflags = 1113 ((struct filedesc0 *) newfdp)->fd_dfileflags; 1114 i = NDFILE; 1115 } else { 1116 /* 1117 * Compute the smallest multiple of NDEXTENT needed 1118 * for the file descriptors currently in use, 1119 * allowing the table to shrink. 1120 */ 1121 i = newfdp->fd_nfiles; 1122 while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2) 1123 i /= 2; 1124 newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK); 1125 newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i]; 1126 } 1127 newfdp->fd_nfiles = i; 1128 bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **)); 1129 bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char)); 1130 1131 /* 1132 * kq descriptors cannot be copied. 1133 */ 1134 if (newfdp->fd_knlistsize != -1) { 1135 fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile]; 1136 for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) { 1137 if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) { 1138 *fpp = NULL; 1139 if (i < newfdp->fd_freefile) 1140 newfdp->fd_freefile = i; 1141 } 1142 if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0) 1143 newfdp->fd_lastfile--; 1144 } 1145 newfdp->fd_knlist = NULL; 1146 newfdp->fd_knlistsize = -1; 1147 newfdp->fd_knhash = NULL; 1148 newfdp->fd_knhashmask = 0; 1149 } 1150 1151 fpp = newfdp->fd_ofiles; 1152 for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) { 1153 if (*fpp != NULL) 1154 fhold(*fpp); 1155 } 1156 return (newfdp); 1157 } 1158 1159 /* 1160 * Release a filedesc structure. 1161 */ 1162 void 1163 fdfree(struct proc *p) 1164 { 1165 struct thread *td = p->p_thread; 1166 struct filedesc *fdp = p->p_fd; 1167 struct file **fpp; 1168 int i; 1169 struct filedesc_to_leader *fdtol; 1170 struct file *fp; 1171 struct vnode *vp; 1172 struct flock lf; 1173 1174 /* Certain daemons might not have file descriptors. */ 1175 if (fdp == NULL) 1176 return; 1177 1178 /* Check for special need to clear POSIX style locks */ 1179 fdtol = p->p_fdtol; 1180 if (fdtol != NULL) { 1181 KASSERT(fdtol->fdl_refcount > 0, 1182 ("filedesc_to_refcount botch: fdl_refcount=%d", 1183 fdtol->fdl_refcount)); 1184 if (fdtol->fdl_refcount == 1 && 1185 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1186 i = 0; 1187 fpp = fdp->fd_ofiles; 1188 for (i = 0, fpp = fdp->fd_ofiles; 1189 i <= fdp->fd_lastfile; 1190 i++, fpp++) { 1191 if (*fpp == NULL || 1192 (*fpp)->f_type != DTYPE_VNODE) 1193 continue; 1194 fp = *fpp; 1195 fhold(fp); 1196 lf.l_whence = SEEK_SET; 1197 lf.l_start = 0; 1198 lf.l_len = 0; 1199 lf.l_type = F_UNLCK; 1200 vp = (struct vnode *)fp->f_data; 1201 (void) VOP_ADVLOCK(vp, 1202 (caddr_t)p->p_leader, 1203 F_UNLCK, 1204 &lf, 1205 F_POSIX); 1206 fdrop(fp, p->p_thread); 1207 fpp = fdp->fd_ofiles + i; 1208 } 1209 } 1210 retry: 1211 if (fdtol->fdl_refcount == 1) { 1212 if (fdp->fd_holdleaderscount > 0 && 1213 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1214 /* 1215 * close() or do_dup() has cleared a reference 1216 * in a shared file descriptor table. 1217 */ 1218 fdp->fd_holdleaderswakeup = 1; 1219 tsleep(&fdp->fd_holdleaderscount, 1220 0, "fdlhold", 0); 1221 goto retry; 1222 } 1223 if (fdtol->fdl_holdcount > 0) { 1224 /* 1225 * Ensure that fdtol->fdl_leader 1226 * remains valid in closef(). 1227 */ 1228 fdtol->fdl_wakeup = 1; 1229 tsleep(fdtol, 0, "fdlhold", 0); 1230 goto retry; 1231 } 1232 } 1233 fdtol->fdl_refcount--; 1234 if (fdtol->fdl_refcount == 0 && 1235 fdtol->fdl_holdcount == 0) { 1236 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1237 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1238 } else 1239 fdtol = NULL; 1240 p->p_fdtol = NULL; 1241 if (fdtol != NULL) 1242 free(fdtol, M_FILEDESC_TO_LEADER); 1243 } 1244 if (--fdp->fd_refcnt > 0) 1245 return; 1246 /* 1247 * we are the last reference to the structure, we can 1248 * safely assume it will not change out from under us. 1249 */ 1250 fpp = fdp->fd_ofiles; 1251 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1252 if (*fpp) 1253 (void) closef(*fpp, td); 1254 } 1255 if (fdp->fd_nfiles > NDFILE) 1256 free(fdp->fd_ofiles, M_FILEDESC); 1257 if (fdp->fd_cdir) { 1258 cache_drop(fdp->fd_ncdir); 1259 vrele(fdp->fd_cdir); 1260 } 1261 if (fdp->fd_rdir) { 1262 cache_drop(fdp->fd_nrdir); 1263 vrele(fdp->fd_rdir); 1264 } 1265 if (fdp->fd_jdir) { 1266 cache_drop(fdp->fd_njdir); 1267 vrele(fdp->fd_jdir); 1268 } 1269 if (fdp->fd_knlist) 1270 free(fdp->fd_knlist, M_KQUEUE); 1271 if (fdp->fd_knhash) 1272 free(fdp->fd_knhash, M_KQUEUE); 1273 free(fdp, M_FILEDESC); 1274 } 1275 1276 /* 1277 * For setugid programs, we don't want to people to use that setugidness 1278 * to generate error messages which write to a file which otherwise would 1279 * otherwise be off-limits to the process. 1280 * 1281 * This is a gross hack to plug the hole. A better solution would involve 1282 * a special vop or other form of generalized access control mechanism. We 1283 * go ahead and just reject all procfs file systems accesses as dangerous. 1284 * 1285 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1286 * sufficient. We also don't for check setugidness since we know we are. 1287 */ 1288 static int 1289 is_unsafe(struct file *fp) 1290 { 1291 if (fp->f_type == DTYPE_VNODE && 1292 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 1293 return (1); 1294 return (0); 1295 } 1296 1297 /* 1298 * Make this setguid thing safe, if at all possible. 1299 */ 1300 void 1301 setugidsafety(struct proc *p) 1302 { 1303 struct thread *td = p->p_thread; 1304 struct filedesc *fdp = p->p_fd; 1305 int i; 1306 1307 /* Certain daemons might not have file descriptors. */ 1308 if (fdp == NULL) 1309 return; 1310 1311 /* 1312 * note: fdp->fd_ofiles may be reallocated out from under us while 1313 * we are blocked in a close. Be careful! 1314 */ 1315 for (i = 0; i <= fdp->fd_lastfile; i++) { 1316 if (i > 2) 1317 break; 1318 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1319 struct file *fp; 1320 1321 #if 0 1322 if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0) 1323 (void) munmapfd(p, i); 1324 #endif 1325 if (i < fdp->fd_knlistsize) 1326 knote_fdclose(p, i); 1327 /* 1328 * NULL-out descriptor prior to close to avoid 1329 * a race while close blocks. 1330 */ 1331 fp = fdp->fd_ofiles[i]; 1332 fdp->fd_ofiles[i] = NULL; 1333 fdp->fd_ofileflags[i] = 0; 1334 if (i < fdp->fd_freefile) 1335 fdp->fd_freefile = i; 1336 (void) closef(fp, td); 1337 } 1338 } 1339 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1340 fdp->fd_lastfile--; 1341 } 1342 1343 /* 1344 * Close any files on exec? 1345 */ 1346 void 1347 fdcloseexec(struct proc *p) 1348 { 1349 struct thread *td = p->p_thread; 1350 struct filedesc *fdp = p->p_fd; 1351 int i; 1352 1353 /* Certain daemons might not have file descriptors. */ 1354 if (fdp == NULL) 1355 return; 1356 1357 /* 1358 * We cannot cache fd_ofiles or fd_ofileflags since operations 1359 * may block and rip them out from under us. 1360 */ 1361 for (i = 0; i <= fdp->fd_lastfile; i++) { 1362 if (fdp->fd_ofiles[i] != NULL && 1363 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1364 struct file *fp; 1365 1366 #if 0 1367 if (fdp->fd_ofileflags[i] & UF_MAPPED) 1368 (void) munmapfd(p, i); 1369 #endif 1370 if (i < fdp->fd_knlistsize) 1371 knote_fdclose(p, i); 1372 /* 1373 * NULL-out descriptor prior to close to avoid 1374 * a race while close blocks. 1375 */ 1376 fp = fdp->fd_ofiles[i]; 1377 fdp->fd_ofiles[i] = NULL; 1378 fdp->fd_ofileflags[i] = 0; 1379 if (i < fdp->fd_freefile) 1380 fdp->fd_freefile = i; 1381 (void) closef(fp, td); 1382 } 1383 } 1384 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1385 fdp->fd_lastfile--; 1386 } 1387 1388 /* 1389 * It is unsafe for set[ug]id processes to be started with file 1390 * descriptors 0..2 closed, as these descriptors are given implicit 1391 * significance in the Standard C library. fdcheckstd() will create a 1392 * descriptor referencing /dev/null for each of stdin, stdout, and 1393 * stderr that is not already open. 1394 */ 1395 int 1396 fdcheckstd(struct proc *p) 1397 { 1398 struct thread *td = p->p_thread; 1399 struct nlookupdata nd; 1400 struct filedesc *fdp; 1401 struct file *fp; 1402 register_t retval; 1403 int fd, i, error, flags, devnull; 1404 1405 fdp = p->p_fd; 1406 if (fdp == NULL) 1407 return (0); 1408 devnull = -1; 1409 error = 0; 1410 for (i = 0; i < 3; i++) { 1411 if (fdp->fd_ofiles[i] != NULL) 1412 continue; 1413 if (devnull < 0) { 1414 if ((error = falloc(p, &fp, NULL)) != 0) 1415 break; 1416 1417 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 1418 NLC_FOLLOW|NLC_LOCKVP); 1419 flags = FREAD | FWRITE; 1420 if (error == 0) 1421 error = vn_open(&nd, fp, flags, 0); 1422 if (error == 0) 1423 error = fsetfd(p, fp, &fd); 1424 fdrop(fp, td); 1425 nlookup_done(&nd); 1426 if (error) 1427 break; 1428 KKASSERT(i == fd); 1429 devnull = fd; 1430 } else { 1431 error = kern_dup(DUP_FIXED, devnull, i, &retval); 1432 if (error != 0) 1433 break; 1434 } 1435 } 1436 return (error); 1437 } 1438 1439 /* 1440 * Internal form of close. 1441 * Decrement reference count on file structure. 1442 * Note: td and/or p may be NULL when closing a file 1443 * that was being passed in a message. 1444 */ 1445 int 1446 closef(struct file *fp, struct thread *td) 1447 { 1448 struct vnode *vp; 1449 struct flock lf; 1450 struct filedesc_to_leader *fdtol; 1451 struct proc *p; 1452 1453 if (fp == NULL) 1454 return (0); 1455 if (td == NULL) { 1456 td = curthread; 1457 p = NULL; /* allow no proc association */ 1458 } else { 1459 p = td->td_proc; /* can also be NULL */ 1460 } 1461 /* 1462 * POSIX record locking dictates that any close releases ALL 1463 * locks owned by this process. This is handled by setting 1464 * a flag in the unlock to free ONLY locks obeying POSIX 1465 * semantics, and not to free BSD-style file locks. 1466 * If the descriptor was in a message, POSIX-style locks 1467 * aren't passed with the descriptor. 1468 */ 1469 if (p != NULL && 1470 fp->f_type == DTYPE_VNODE) { 1471 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) { 1472 lf.l_whence = SEEK_SET; 1473 lf.l_start = 0; 1474 lf.l_len = 0; 1475 lf.l_type = F_UNLCK; 1476 vp = (struct vnode *)fp->f_data; 1477 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 1478 &lf, F_POSIX); 1479 } 1480 fdtol = p->p_fdtol; 1481 if (fdtol != NULL) { 1482 /* 1483 * Handle special case where file descriptor table 1484 * is shared between multiple process leaders. 1485 */ 1486 for (fdtol = fdtol->fdl_next; 1487 fdtol != p->p_fdtol; 1488 fdtol = fdtol->fdl_next) { 1489 if ((fdtol->fdl_leader->p_flag & 1490 P_ADVLOCK) == 0) 1491 continue; 1492 fdtol->fdl_holdcount++; 1493 lf.l_whence = SEEK_SET; 1494 lf.l_start = 0; 1495 lf.l_len = 0; 1496 lf.l_type = F_UNLCK; 1497 vp = (struct vnode *)fp->f_data; 1498 (void) VOP_ADVLOCK(vp, 1499 (caddr_t)p->p_leader, 1500 F_UNLCK, &lf, F_POSIX); 1501 fdtol->fdl_holdcount--; 1502 if (fdtol->fdl_holdcount == 0 && 1503 fdtol->fdl_wakeup != 0) { 1504 fdtol->fdl_wakeup = 0; 1505 wakeup(fdtol); 1506 } 1507 } 1508 } 1509 } 1510 return (fdrop(fp, td)); 1511 } 1512 1513 int 1514 fdrop(struct file *fp, struct thread *td) 1515 { 1516 struct flock lf; 1517 struct vnode *vp; 1518 int error; 1519 1520 if (--fp->f_count > 0) 1521 return (0); 1522 if (fp->f_count < 0) 1523 panic("fdrop: count < 0"); 1524 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 1525 lf.l_whence = SEEK_SET; 1526 lf.l_start = 0; 1527 lf.l_len = 0; 1528 lf.l_type = F_UNLCK; 1529 vp = (struct vnode *)fp->f_data; 1530 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 1531 } 1532 if (fp->f_ops != &badfileops) 1533 error = fo_close(fp, td); 1534 else 1535 error = 0; 1536 ffree(fp); 1537 return (error); 1538 } 1539 1540 /* 1541 * Apply an advisory lock on a file descriptor. 1542 * 1543 * Just attempt to get a record lock of the requested type on 1544 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 1545 */ 1546 /* ARGSUSED */ 1547 int 1548 flock(struct flock_args *uap) 1549 { 1550 struct proc *p = curproc; 1551 struct filedesc *fdp = p->p_fd; 1552 struct file *fp; 1553 struct vnode *vp; 1554 struct flock lf; 1555 1556 if ((unsigned)uap->fd >= fdp->fd_nfiles || 1557 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 1558 return (EBADF); 1559 if (fp->f_type != DTYPE_VNODE) 1560 return (EOPNOTSUPP); 1561 vp = (struct vnode *)fp->f_data; 1562 lf.l_whence = SEEK_SET; 1563 lf.l_start = 0; 1564 lf.l_len = 0; 1565 if (uap->how & LOCK_UN) { 1566 lf.l_type = F_UNLCK; 1567 fp->f_flag &= ~FHASLOCK; 1568 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK)); 1569 } 1570 if (uap->how & LOCK_EX) 1571 lf.l_type = F_WRLCK; 1572 else if (uap->how & LOCK_SH) 1573 lf.l_type = F_RDLCK; 1574 else 1575 return (EBADF); 1576 fp->f_flag |= FHASLOCK; 1577 if (uap->how & LOCK_NB) 1578 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK)); 1579 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT)); 1580 } 1581 1582 /* 1583 * File Descriptor pseudo-device driver (/dev/fd/). 1584 * 1585 * Opening minor device N dup()s the file (if any) connected to file 1586 * descriptor N belonging to the calling process. Note that this driver 1587 * consists of only the ``open()'' routine, because all subsequent 1588 * references to this file will be direct to the other driver. 1589 */ 1590 /* ARGSUSED */ 1591 static int 1592 fdopen(dev_t dev, int mode, int type, struct thread *td) 1593 { 1594 KKASSERT(td->td_proc != NULL); 1595 1596 /* 1597 * XXX Kludge: set curproc->p_dupfd to contain the value of the 1598 * the file descriptor being sought for duplication. The error 1599 * return ensures that the vnode for this device will be released 1600 * by vn_open. Open will detect this special error and take the 1601 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 1602 * will simply report the error. 1603 */ 1604 td->td_proc->p_dupfd = minor(dev); 1605 return (ENODEV); 1606 } 1607 1608 /* 1609 * Duplicate the specified descriptor to a free descriptor. 1610 */ 1611 int 1612 dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode, int error) 1613 { 1614 struct file *wfp; 1615 struct file *fp; 1616 1617 /* 1618 * If the to-be-dup'd fd number is greater than the allowed number 1619 * of file descriptors, or the fd to be dup'd has already been 1620 * closed, then reject. 1621 */ 1622 if ((u_int)dfd >= fdp->fd_nfiles || 1623 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 1624 return (EBADF); 1625 } 1626 1627 /* 1628 * There are two cases of interest here. 1629 * 1630 * For ENODEV simply dup (dfd) to file descriptor 1631 * (indx) and return. 1632 * 1633 * For ENXIO steal away the file structure from (dfd) and 1634 * store it in (indx). (dfd) is effectively closed by 1635 * this operation. 1636 * 1637 * Any other error code is just returned. 1638 */ 1639 switch (error) { 1640 case ENODEV: 1641 /* 1642 * Check that the mode the file is being opened for is a 1643 * subset of the mode of the existing descriptor. 1644 */ 1645 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) 1646 return (EACCES); 1647 fp = fdp->fd_ofiles[indx]; 1648 #if 0 1649 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1650 (void) munmapfd(p, indx); 1651 #endif 1652 fdp->fd_ofiles[indx] = wfp; 1653 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1654 fhold(wfp); 1655 if (indx > fdp->fd_lastfile) 1656 fdp->fd_lastfile = indx; 1657 /* 1658 * we now own the reference to fp that the ofiles[] array 1659 * used to own. Release it. 1660 */ 1661 if (fp) 1662 fdrop(fp, curthread); 1663 return (0); 1664 1665 case ENXIO: 1666 /* 1667 * Steal away the file pointer from dfd, and stuff it into indx. 1668 */ 1669 fp = fdp->fd_ofiles[indx]; 1670 #if 0 1671 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1672 (void) munmapfd(p, indx); 1673 #endif 1674 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 1675 fdp->fd_ofiles[dfd] = NULL; 1676 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1677 fdp->fd_ofileflags[dfd] = 0; 1678 1679 /* 1680 * we now own the reference to fp that the ofiles[] array 1681 * used to own. Release it. 1682 */ 1683 if (fp) 1684 fdrop(fp, curthread); 1685 /* 1686 * Complete the clean up of the filedesc structure by 1687 * recomputing the various hints. 1688 */ 1689 if (indx > fdp->fd_lastfile) { 1690 fdp->fd_lastfile = indx; 1691 } else { 1692 while (fdp->fd_lastfile > 0 && 1693 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) { 1694 fdp->fd_lastfile--; 1695 } 1696 if (dfd < fdp->fd_freefile) 1697 fdp->fd_freefile = dfd; 1698 } 1699 return (0); 1700 1701 default: 1702 return (error); 1703 } 1704 /* NOTREACHED */ 1705 } 1706 1707 1708 struct filedesc_to_leader * 1709 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 1710 struct proc *leader) 1711 { 1712 struct filedesc_to_leader *fdtol; 1713 1714 fdtol = malloc(sizeof(struct filedesc_to_leader), 1715 M_FILEDESC_TO_LEADER, M_WAITOK); 1716 fdtol->fdl_refcount = 1; 1717 fdtol->fdl_holdcount = 0; 1718 fdtol->fdl_wakeup = 0; 1719 fdtol->fdl_leader = leader; 1720 if (old != NULL) { 1721 fdtol->fdl_next = old->fdl_next; 1722 fdtol->fdl_prev = old; 1723 old->fdl_next = fdtol; 1724 fdtol->fdl_next->fdl_prev = fdtol; 1725 } else { 1726 fdtol->fdl_next = fdtol; 1727 fdtol->fdl_prev = fdtol; 1728 } 1729 return fdtol; 1730 } 1731 1732 /* 1733 * Get file structures. 1734 */ 1735 static int 1736 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 1737 { 1738 struct kinfo_file kf; 1739 struct filedesc *fdp; 1740 struct file *fp; 1741 struct proc *p; 1742 int count; 1743 int error; 1744 int n; 1745 1746 /* 1747 * Note: because the number of file descriptors is calculated 1748 * in different ways for sizing vs returning the data, 1749 * there is information leakage from the first loop. However, 1750 * it is of a similar order of magnitude to the leakage from 1751 * global system statistics such as kern.openfiles. 1752 * 1753 * When just doing a count, note that we cannot just count 1754 * the elements and add f_count via the filehead list because 1755 * threaded processes share their descriptor table and f_count might 1756 * still be '1' in that case. 1757 */ 1758 count = 0; 1759 error = 0; 1760 LIST_FOREACH(p, &allproc, p_list) { 1761 if (p->p_stat == SIDL) 1762 continue; 1763 if (!PRISON_CHECK(req->td->td_proc->p_ucred, p->p_ucred) != 0) 1764 continue; 1765 if ((fdp = p->p_fd) == NULL) 1766 continue; 1767 for (n = 0; n < fdp->fd_nfiles; ++n) { 1768 if ((fp = fdp->fd_ofiles[n]) == NULL) 1769 continue; 1770 if (req->oldptr == NULL) { 1771 ++count; 1772 } else { 1773 kcore_make_file(&kf, fp, p->p_pid, 1774 p->p_ucred->cr_uid, n); 1775 error = SYSCTL_OUT(req, &kf, sizeof(kf)); 1776 if (error) 1777 break; 1778 } 1779 } 1780 if (error) 1781 break; 1782 } 1783 1784 /* 1785 * When just calculating the size, overestimate a bit to try to 1786 * prevent system activity from causing the buffer-fill call 1787 * to fail later on. 1788 */ 1789 if (req->oldptr == NULL) { 1790 count = (count + 16) + (count / 10); 1791 error = SYSCTL_OUT(req, NULL, count * sizeof(kf)); 1792 } 1793 return (error); 1794 } 1795 1796 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 1797 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 1798 1799 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 1800 &maxfilesperproc, 0, "Maximum files allowed open per process"); 1801 1802 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 1803 &maxfiles, 0, "Maximum number of files"); 1804 1805 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 1806 &maxfilesrootres, 0, "Descriptors reserved for root use"); 1807 1808 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 1809 &nfiles, 0, "System-wide number of open files"); 1810 1811 static void 1812 fildesc_drvinit(void *unused) 1813 { 1814 int fd; 1815 1816 cdevsw_add(&fildesc_cdevsw, 0, 0); 1817 for (fd = 0; fd < NUMFDESC; fd++) { 1818 make_dev(&fildesc_cdevsw, fd, 1819 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 1820 } 1821 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 1822 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 1823 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 1824 } 1825 1826 struct fileops badfileops = { 1827 NULL, /* port */ 1828 NULL, /* clone */ 1829 badfo_readwrite, 1830 badfo_readwrite, 1831 badfo_ioctl, 1832 badfo_poll, 1833 badfo_kqfilter, 1834 badfo_stat, 1835 badfo_close 1836 }; 1837 1838 static int 1839 badfo_readwrite( 1840 struct file *fp, 1841 struct uio *uio, 1842 struct ucred *cred, 1843 int flags, 1844 struct thread *td 1845 ) { 1846 return (EBADF); 1847 } 1848 1849 static int 1850 badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td) 1851 { 1852 return (EBADF); 1853 } 1854 1855 static int 1856 badfo_poll(struct file *fp, int events, struct ucred *cred, struct thread *td) 1857 { 1858 return (0); 1859 } 1860 1861 static int 1862 badfo_kqfilter(struct file *fp, struct knote *kn) 1863 { 1864 return (0); 1865 } 1866 1867 static int 1868 badfo_stat(struct file *fp, struct stat *sb, struct thread *td) 1869 { 1870 return (EBADF); 1871 } 1872 1873 static int 1874 badfo_close(struct file *fp, struct thread *td) 1875 { 1876 return (EBADF); 1877 } 1878 1879 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 1880 fildesc_drvinit,NULL) 1881