Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_descrip.c
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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 * $FreeBSD$ 40 */ 41 42 #include "opt_compat.h" 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/malloc.h> 46 #include <sys/sysproto.h> 47 #include <sys/conf.h> 48 #include <sys/filedesc.h> 49 #include <sys/kernel.h> 50 #include <sys/sysctl.h> 51 #include <sys/vnode.h> 52 #include <sys/proc.h> 53 #include <sys/namei.h> 54 #include <sys/file.h> 55 #include <sys/stat.h> 56 #include <sys/filio.h> 57 #include <sys/fcntl.h> 58 #include <sys/unistd.h> 59 #include <sys/resourcevar.h> 60 #include <sys/event.h> 61 62 #include <vm/vm.h> 63 #include <vm/vm_extern.h> 64 65 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 66 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 67 "file desc to leader structures"); 68 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 69 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 70 71 static d_open_t fdopen; 72 #define NUMFDESC 64 73 74 #define CDEV_MAJOR 22 75 static struct cdevsw fildesc_cdevsw = { 76 /* open */ fdopen, 77 /* close */ noclose, 78 /* read */ noread, 79 /* write */ nowrite, 80 /* ioctl */ noioctl, 81 /* poll */ nopoll, 82 /* mmap */ nommap, 83 /* strategy */ nostrategy, 84 /* name */ "FD", 85 /* maj */ CDEV_MAJOR, 86 /* dump */ nodump, 87 /* psize */ nopsize, 88 /* flags */ 0, 89 /* bmaj */ -1 90 }; 91 92 static int do_dup __P((struct filedesc *fdp, int old, int new, register_t *retval, struct proc *p)); 93 static int badfo_readwrite __P((struct file *fp, struct uio *uio, 94 struct ucred *cred, int flags, struct proc *p)); 95 static int badfo_ioctl __P((struct file *fp, u_long com, caddr_t data, 96 struct proc *p)); 97 static int badfo_poll __P((struct file *fp, int events, 98 struct ucred *cred, struct proc *p)); 99 static int badfo_kqfilter __P((struct file *fp, struct knote *kn)); 100 static int badfo_stat __P((struct file *fp, struct stat *sb, struct proc *p)); 101 static int badfo_close __P((struct file *fp, struct proc *p)); 102 103 /* 104 * Descriptor management. 105 */ 106 struct filelist filehead; /* head of list of open files */ 107 int nfiles; /* actual number of open files */ 108 extern int cmask; 109 110 /* 111 * System calls on descriptors. 112 */ 113 #ifndef _SYS_SYSPROTO_H_ 114 struct getdtablesize_args { 115 int dummy; 116 }; 117 #endif 118 /* ARGSUSED */ 119 int 120 getdtablesize(p, uap) 121 struct proc *p; 122 struct getdtablesize_args *uap; 123 { 124 125 p->p_retval[0] = 126 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 127 return (0); 128 } 129 130 /* 131 * Duplicate a file descriptor to a particular value. 132 * 133 * note: keep in mind that a potential race condition exists when closing 134 * descriptors from a shared descriptor table (via rfork). 135 */ 136 #ifndef _SYS_SYSPROTO_H_ 137 struct dup2_args { 138 u_int from; 139 u_int to; 140 }; 141 #endif 142 /* ARGSUSED */ 143 int 144 dup2(p, uap) 145 struct proc *p; 146 struct dup2_args *uap; 147 { 148 register struct filedesc *fdp = p->p_fd; 149 register u_int old = uap->from, new = uap->to; 150 int i, error; 151 152 retry: 153 if (old >= fdp->fd_nfiles || 154 fdp->fd_ofiles[old] == NULL || 155 new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 156 new >= maxfilesperproc) { 157 return (EBADF); 158 } 159 if (old == new) { 160 p->p_retval[0] = new; 161 return (0); 162 } 163 if (new >= fdp->fd_nfiles) { 164 if ((error = fdalloc(p, new, &i))) 165 return (error); 166 /* 167 * fdalloc() may block, retest everything. 168 */ 169 goto retry; 170 } 171 return (do_dup(fdp, (int)old, (int)new, p->p_retval, p)); 172 } 173 174 /* 175 * Duplicate a file descriptor. 176 */ 177 #ifndef _SYS_SYSPROTO_H_ 178 struct dup_args { 179 u_int fd; 180 }; 181 #endif 182 /* ARGSUSED */ 183 int 184 dup(p, uap) 185 struct proc *p; 186 struct dup_args *uap; 187 { 188 register struct filedesc *fdp; 189 u_int old; 190 int new, error; 191 192 old = uap->fd; 193 fdp = p->p_fd; 194 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) 195 return (EBADF); 196 if ((error = fdalloc(p, 0, &new))) 197 return (error); 198 return (do_dup(fdp, (int)old, new, p->p_retval, p)); 199 } 200 201 /* 202 * The file control system call. 203 */ 204 #ifndef _SYS_SYSPROTO_H_ 205 struct fcntl_args { 206 int fd; 207 int cmd; 208 long arg; 209 }; 210 #endif 211 /* ARGSUSED */ 212 int 213 fcntl(p, uap) 214 struct proc *p; 215 register struct fcntl_args *uap; 216 { 217 register struct filedesc *fdp = p->p_fd; 218 register struct file *fp; 219 register char *pop; 220 struct vnode *vp; 221 int i, tmp, error, flg = F_POSIX; 222 struct flock fl; 223 u_int newmin; 224 225 if ((unsigned)uap->fd >= fdp->fd_nfiles || 226 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 227 return (EBADF); 228 pop = &fdp->fd_ofileflags[uap->fd]; 229 230 switch (uap->cmd) { 231 case F_DUPFD: 232 newmin = uap->arg; 233 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur || 234 newmin >= maxfilesperproc) 235 return (EINVAL); 236 if ((error = fdalloc(p, newmin, &i))) 237 return (error); 238 return (do_dup(fdp, uap->fd, i, p->p_retval, p)); 239 240 case F_GETFD: 241 p->p_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 242 return (0); 243 244 case F_SETFD: 245 *pop = (*pop &~ UF_EXCLOSE) | 246 (uap->arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 247 return (0); 248 249 case F_GETFL: 250 p->p_retval[0] = OFLAGS(fp->f_flag); 251 return (0); 252 253 case F_SETFL: 254 fhold(fp); 255 fp->f_flag &= ~FCNTLFLAGS; 256 fp->f_flag |= FFLAGS(uap->arg & ~O_ACCMODE) & FCNTLFLAGS; 257 tmp = fp->f_flag & FNONBLOCK; 258 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, p); 259 if (error) { 260 fdrop(fp, p); 261 return (error); 262 } 263 tmp = fp->f_flag & FASYNC; 264 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, p); 265 if (!error) { 266 fdrop(fp, p); 267 return (0); 268 } 269 fp->f_flag &= ~FNONBLOCK; 270 tmp = 0; 271 (void)fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, p); 272 fdrop(fp, p); 273 return (error); 274 275 case F_GETOWN: 276 fhold(fp); 277 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)p->p_retval, p); 278 fdrop(fp, p); 279 return(error); 280 281 case F_SETOWN: 282 fhold(fp); 283 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&uap->arg, p); 284 fdrop(fp, p); 285 return(error); 286 287 case F_SETLKW: 288 flg |= F_WAIT; 289 /* Fall into F_SETLK */ 290 291 case F_SETLK: 292 if (fp->f_type != DTYPE_VNODE) 293 return (EBADF); 294 vp = (struct vnode *)fp->f_data; 295 296 /* 297 * copyin/lockop may block 298 */ 299 fhold(fp); 300 /* Copy in the lock structure */ 301 error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl, 302 sizeof(fl)); 303 if (error) { 304 fdrop(fp, p); 305 return (error); 306 } 307 if (fl.l_whence == SEEK_CUR) 308 fl.l_start += fp->f_offset; 309 310 switch (fl.l_type) { 311 case F_RDLCK: 312 if ((fp->f_flag & FREAD) == 0) { 313 error = EBADF; 314 break; 315 } 316 p->p_leader->p_flag |= P_ADVLOCK; 317 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 318 &fl, flg); 319 break; 320 case F_WRLCK: 321 if ((fp->f_flag & FWRITE) == 0) { 322 error = EBADF; 323 break; 324 } 325 p->p_leader->p_flag |= P_ADVLOCK; 326 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 327 &fl, flg); 328 break; 329 case F_UNLCK: 330 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 331 &fl, F_POSIX); 332 break; 333 default: 334 error = EINVAL; 335 break; 336 } 337 /* Check for race with close */ 338 if ((unsigned) uap->fd >= fdp->fd_nfiles || 339 fp != fdp->fd_ofiles[uap->fd]) { 340 fl.l_whence = SEEK_SET; 341 fl.l_start = 0; 342 fl.l_len = 0; 343 fl.l_type = F_UNLCK; 344 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 345 F_UNLCK, &fl, F_POSIX); 346 } 347 fdrop(fp, p); 348 return(error); 349 350 case F_GETLK: 351 if (fp->f_type != DTYPE_VNODE) 352 return (EBADF); 353 vp = (struct vnode *)fp->f_data; 354 /* 355 * copyin/lockop may block 356 */ 357 fhold(fp); 358 /* Copy in the lock structure */ 359 error = copyin((caddr_t)(intptr_t)uap->arg, (caddr_t)&fl, 360 sizeof(fl)); 361 if (error) { 362 fdrop(fp, p); 363 return (error); 364 } 365 if (fl.l_type != F_RDLCK && fl.l_type != F_WRLCK && 366 fl.l_type != F_UNLCK) { 367 fdrop(fp, p); 368 return (EINVAL); 369 } 370 if (fl.l_whence == SEEK_CUR) 371 fl.l_start += fp->f_offset; 372 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 373 &fl, F_POSIX); 374 fdrop(fp, p); 375 if (error == 0) { 376 error = copyout((caddr_t)&fl, 377 (caddr_t)(intptr_t)uap->arg, sizeof(fl)); 378 } 379 return(error); 380 default: 381 return (EINVAL); 382 } 383 /* NOTREACHED */ 384 } 385 386 /* 387 * Common code for dup, dup2, and fcntl(F_DUPFD). 388 */ 389 static int 390 do_dup(fdp, old, new, retval, p) 391 register struct filedesc *fdp; 392 register int old, new; 393 register_t *retval; 394 struct proc *p; 395 { 396 struct file *fp; 397 struct file *delfp; 398 int holdleaders; 399 400 /* 401 * Save info on the descriptor being overwritten. We have 402 * to do the unmap now, but we cannot close it without 403 * introducing an ownership race for the slot. 404 */ 405 delfp = fdp->fd_ofiles[new]; 406 if (delfp != NULL && p->p_fdtol != NULL) { 407 /* 408 * Ask fdfree() to sleep to ensure that all relevant 409 * process leaders can be traversed in closef(). 410 */ 411 fdp->fd_holdleaderscount++; 412 holdleaders = 1; 413 } else 414 holdleaders = 0; 415 #if 0 416 if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED)) 417 (void) munmapfd(p, new); 418 #endif 419 420 /* 421 * Duplicate the source descriptor, update lastfile 422 */ 423 fp = fdp->fd_ofiles[old]; 424 fdp->fd_ofiles[new] = fp; 425 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 426 fhold(fp); 427 if (new > fdp->fd_lastfile) 428 fdp->fd_lastfile = new; 429 *retval = new; 430 431 /* 432 * If we dup'd over a valid file, we now own the reference to it 433 * and must dispose of it using closef() semantics (as if a 434 * close() were performed on it). 435 */ 436 if (delfp) { 437 (void) closef(delfp, p); 438 if (holdleaders) { 439 fdp->fd_holdleaderscount--; 440 if (fdp->fd_holdleaderscount == 0 && 441 fdp->fd_holdleaderswakeup != 0) { 442 fdp->fd_holdleaderswakeup = 0; 443 wakeup(&fdp->fd_holdleaderscount); 444 } 445 } 446 } 447 return (0); 448 } 449 450 /* 451 * If sigio is on the list associated with a process or process group, 452 * disable signalling from the device, remove sigio from the list and 453 * free sigio. 454 */ 455 void 456 funsetown(sigio) 457 struct sigio *sigio; 458 { 459 int s; 460 461 if (sigio == NULL) 462 return; 463 s = splhigh(); 464 *(sigio->sio_myref) = NULL; 465 splx(s); 466 if (sigio->sio_pgid < 0) { 467 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 468 sigio, sio_pgsigio); 469 } else /* if ((*sigiop)->sio_pgid > 0) */ { 470 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 471 sigio, sio_pgsigio); 472 } 473 crfree(sigio->sio_ucred); 474 FREE(sigio, M_SIGIO); 475 } 476 477 /* Free a list of sigio structures. */ 478 void 479 funsetownlst(sigiolst) 480 struct sigiolst *sigiolst; 481 { 482 struct sigio *sigio; 483 484 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 485 funsetown(sigio); 486 } 487 488 /* 489 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 490 * 491 * After permission checking, add a sigio structure to the sigio list for 492 * the process or process group. 493 */ 494 int 495 fsetown(pgid, sigiop) 496 pid_t pgid; 497 struct sigio **sigiop; 498 { 499 struct proc *proc; 500 struct pgrp *pgrp; 501 struct sigio *sigio; 502 int s; 503 504 if (pgid == 0) { 505 funsetown(*sigiop); 506 return (0); 507 } 508 if (pgid > 0) { 509 proc = pfind(pgid); 510 if (proc == NULL) 511 return (ESRCH); 512 513 /* 514 * Policy - Don't allow a process to FSETOWN a process 515 * in another session. 516 * 517 * Remove this test to allow maximum flexibility or 518 * restrict FSETOWN to the current process or process 519 * group for maximum safety. 520 */ 521 if (proc->p_session != curproc->p_session) 522 return (EPERM); 523 524 pgrp = NULL; 525 } else /* if (pgid < 0) */ { 526 pgrp = pgfind(-pgid); 527 if (pgrp == NULL) 528 return (ESRCH); 529 530 /* 531 * Policy - Don't allow a process to FSETOWN a process 532 * in another session. 533 * 534 * Remove this test to allow maximum flexibility or 535 * restrict FSETOWN to the current process or process 536 * group for maximum safety. 537 */ 538 if (pgrp->pg_session != curproc->p_session) 539 return (EPERM); 540 541 proc = NULL; 542 } 543 funsetown(*sigiop); 544 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 545 if (pgid > 0) { 546 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 547 sigio->sio_proc = proc; 548 } else { 549 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 550 sigio->sio_pgrp = pgrp; 551 } 552 sigio->sio_pgid = pgid; 553 crhold(curproc->p_ucred); 554 sigio->sio_ucred = curproc->p_ucred; 555 /* It would be convenient if p_ruid was in ucred. */ 556 sigio->sio_ruid = curproc->p_cred->p_ruid; 557 sigio->sio_myref = sigiop; 558 s = splhigh(); 559 *sigiop = sigio; 560 splx(s); 561 return (0); 562 } 563 564 /* 565 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 566 */ 567 pid_t 568 fgetown(sigio) 569 struct sigio *sigio; 570 { 571 return (sigio != NULL ? sigio->sio_pgid : 0); 572 } 573 574 /* 575 * Close a file descriptor. 576 */ 577 #ifndef _SYS_SYSPROTO_H_ 578 struct close_args { 579 int fd; 580 }; 581 #endif 582 /* ARGSUSED */ 583 int 584 close(p, uap) 585 struct proc *p; 586 struct close_args *uap; 587 { 588 register struct filedesc *fdp = p->p_fd; 589 register struct file *fp; 590 register int fd = uap->fd; 591 int error; 592 int holdleaders; 593 594 if ((unsigned)fd >= fdp->fd_nfiles || 595 (fp = fdp->fd_ofiles[fd]) == NULL) 596 return (EBADF); 597 #if 0 598 if (fdp->fd_ofileflags[fd] & UF_MAPPED) 599 (void) munmapfd(p, fd); 600 #endif 601 fdp->fd_ofiles[fd] = NULL; 602 fdp->fd_ofileflags[fd] = 0; 603 holdleaders = 0; 604 if (p->p_fdtol != NULL) { 605 /* 606 * Ask fdfree() to sleep to ensure that all relevant 607 * process leaders can be traversed in closef(). 608 */ 609 fdp->fd_holdleaderscount++; 610 holdleaders = 1; 611 } 612 613 /* 614 * we now hold the fp reference that used to be owned by the descriptor 615 * array. 616 */ 617 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 618 fdp->fd_lastfile--; 619 if (fd < fdp->fd_freefile) 620 fdp->fd_freefile = fd; 621 if (fd < fdp->fd_knlistsize) 622 knote_fdclose(p, fd); 623 error = closef(fp, p); 624 if (holdleaders) { 625 fdp->fd_holdleaderscount--; 626 if (fdp->fd_holdleaderscount == 0 && 627 fdp->fd_holdleaderswakeup != 0) { 628 fdp->fd_holdleaderswakeup = 0; 629 wakeup(&fdp->fd_holdleaderscount); 630 } 631 } 632 return (error); 633 } 634 635 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) 636 /* 637 * Return status information about a file descriptor. 638 */ 639 #ifndef _SYS_SYSPROTO_H_ 640 struct ofstat_args { 641 int fd; 642 struct ostat *sb; 643 }; 644 #endif 645 /* ARGSUSED */ 646 int 647 ofstat(p, uap) 648 struct proc *p; 649 register struct ofstat_args *uap; 650 { 651 register struct filedesc *fdp = p->p_fd; 652 register struct file *fp; 653 struct stat ub; 654 struct ostat oub; 655 int error; 656 657 if ((unsigned)uap->fd >= fdp->fd_nfiles || 658 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 659 return (EBADF); 660 fhold(fp); 661 error = fo_stat(fp, &ub, p); 662 if (error == 0) { 663 cvtstat(&ub, &oub); 664 error = copyout((caddr_t)&oub, (caddr_t)uap->sb, sizeof (oub)); 665 } 666 fdrop(fp, p); 667 return (error); 668 } 669 #endif /* COMPAT_43 || COMPAT_SUNOS */ 670 671 /* 672 * Return status information about a file descriptor. 673 */ 674 #ifndef _SYS_SYSPROTO_H_ 675 struct fstat_args { 676 int fd; 677 struct stat *sb; 678 }; 679 #endif 680 /* ARGSUSED */ 681 int 682 fstat(p, uap) 683 struct proc *p; 684 register struct fstat_args *uap; 685 { 686 register struct filedesc *fdp = p->p_fd; 687 register struct file *fp; 688 struct stat ub; 689 int error; 690 691 if ((unsigned)uap->fd >= fdp->fd_nfiles || 692 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 693 return (EBADF); 694 fhold(fp); 695 error = fo_stat(fp, &ub, p); 696 if (error == 0) 697 error = copyout((caddr_t)&ub, (caddr_t)uap->sb, sizeof (ub)); 698 fdrop(fp, p); 699 return (error); 700 } 701 702 /* 703 * Return status information about a file descriptor. 704 */ 705 #ifndef _SYS_SYSPROTO_H_ 706 struct nfstat_args { 707 int fd; 708 struct nstat *sb; 709 }; 710 #endif 711 /* ARGSUSED */ 712 int 713 nfstat(p, uap) 714 struct proc *p; 715 register struct nfstat_args *uap; 716 { 717 register struct filedesc *fdp = p->p_fd; 718 register struct file *fp; 719 struct stat ub; 720 struct nstat nub; 721 int error; 722 723 if ((unsigned)uap->fd >= fdp->fd_nfiles || 724 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 725 return (EBADF); 726 fhold(fp); 727 error = fo_stat(fp, &ub, p); 728 if (error == 0) { 729 cvtnstat(&ub, &nub); 730 error = copyout((caddr_t)&nub, (caddr_t)uap->sb, sizeof (nub)); 731 } 732 fdrop(fp, p); 733 return (error); 734 } 735 736 /* 737 * Return pathconf information about a file descriptor. 738 */ 739 #ifndef _SYS_SYSPROTO_H_ 740 struct fpathconf_args { 741 int fd; 742 int name; 743 }; 744 #endif 745 /* ARGSUSED */ 746 int 747 fpathconf(p, uap) 748 struct proc *p; 749 register struct fpathconf_args *uap; 750 { 751 struct filedesc *fdp = p->p_fd; 752 struct file *fp; 753 struct vnode *vp; 754 int error = 0; 755 756 if ((unsigned)uap->fd >= fdp->fd_nfiles || 757 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 758 return (EBADF); 759 760 fhold(fp); 761 762 switch (fp->f_type) { 763 case DTYPE_PIPE: 764 case DTYPE_SOCKET: 765 if (uap->name != _PC_PIPE_BUF) { 766 error = EINVAL; 767 } else { 768 p->p_retval[0] = PIPE_BUF; 769 error = 0; 770 } 771 break; 772 case DTYPE_FIFO: 773 case DTYPE_VNODE: 774 vp = (struct vnode *)fp->f_data; 775 error = VOP_PATHCONF(vp, uap->name, p->p_retval); 776 break; 777 default: 778 error = EOPNOTSUPP; 779 break; 780 } 781 fdrop(fp, p); 782 return(error); 783 } 784 785 /* 786 * Allocate a file descriptor for the process. 787 */ 788 static int fdexpand; 789 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, ""); 790 791 int 792 fdalloc(p, want, result) 793 struct proc *p; 794 int want; 795 int *result; 796 { 797 register struct filedesc *fdp = p->p_fd; 798 register int i; 799 int lim, last, nfiles; 800 struct file **newofile; 801 char *newofileflags; 802 803 /* 804 * Search for a free descriptor starting at the higher 805 * of want or fd_freefile. If that fails, consider 806 * expanding the ofile array. 807 */ 808 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 809 for (;;) { 810 last = min(fdp->fd_nfiles, lim); 811 if ((i = want) < fdp->fd_freefile) 812 i = fdp->fd_freefile; 813 for (; i < last; i++) { 814 if (fdp->fd_ofiles[i] == NULL) { 815 fdp->fd_ofileflags[i] = 0; 816 if (i > fdp->fd_lastfile) 817 fdp->fd_lastfile = i; 818 if (want <= fdp->fd_freefile) 819 fdp->fd_freefile = i; 820 *result = i; 821 return (0); 822 } 823 } 824 825 /* 826 * No space in current array. Expand? 827 */ 828 if (fdp->fd_nfiles >= lim) 829 return (EMFILE); 830 if (fdp->fd_nfiles < NDEXTENT) 831 nfiles = NDEXTENT; 832 else 833 nfiles = 2 * fdp->fd_nfiles; 834 MALLOC(newofile, struct file **, nfiles * OFILESIZE, 835 M_FILEDESC, M_WAITOK); 836 837 /* 838 * deal with file-table extend race that might have occured 839 * when malloc was blocked. 840 */ 841 if (fdp->fd_nfiles >= nfiles) { 842 FREE(newofile, M_FILEDESC); 843 continue; 844 } 845 newofileflags = (char *) &newofile[nfiles]; 846 /* 847 * Copy the existing ofile and ofileflags arrays 848 * and zero the new portion of each array. 849 */ 850 bcopy(fdp->fd_ofiles, newofile, 851 (i = sizeof(struct file *) * fdp->fd_nfiles)); 852 bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i); 853 bcopy(fdp->fd_ofileflags, newofileflags, 854 (i = sizeof(char) * fdp->fd_nfiles)); 855 bzero(newofileflags + i, nfiles * sizeof(char) - i); 856 if (fdp->fd_nfiles > NDFILE) 857 FREE(fdp->fd_ofiles, M_FILEDESC); 858 fdp->fd_ofiles = newofile; 859 fdp->fd_ofileflags = newofileflags; 860 fdp->fd_nfiles = nfiles; 861 fdexpand++; 862 } 863 return (0); 864 } 865 866 /* 867 * Check to see whether n user file descriptors 868 * are available to the process p. 869 */ 870 int 871 fdavail(p, n) 872 struct proc *p; 873 register int n; 874 { 875 register struct filedesc *fdp = p->p_fd; 876 register struct file **fpp; 877 register int i, lim, last; 878 879 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); 880 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 881 return (1); 882 883 last = min(fdp->fd_nfiles, lim); 884 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 885 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 886 if (*fpp == NULL && --n <= 0) 887 return (1); 888 } 889 return (0); 890 } 891 892 /* 893 * Create a new open file structure and allocate 894 * a file decriptor for the process that refers to it. 895 */ 896 int 897 falloc(p, resultfp, resultfd) 898 register struct proc *p; 899 struct file **resultfp; 900 int *resultfd; 901 { 902 register struct file *fp, *fq; 903 int error, i; 904 int maxuserfiles = maxfiles - (maxfiles / 20); 905 static struct timeval lastfail; 906 static int curfail; 907 908 if ((nfiles >= maxuserfiles && p->p_cred->p_ruid != 0) 909 || nfiles >= maxfiles) { 910 if (ppsratecheck(&lastfail, &curfail, 1)) { 911 printf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n", 912 p->p_cred->p_ruid); 913 } 914 return (ENFILE); 915 } 916 /* 917 * Allocate a new file descriptor. 918 * If the process has file descriptor zero open, add to the list 919 * of open files at that point, otherwise put it at the front of 920 * the list of open files. 921 */ 922 nfiles++; 923 MALLOC(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK); 924 bzero(fp, sizeof(struct file)); 925 926 /* 927 * wait until after malloc (which may have blocked) returns before 928 * allocating the slot, else a race might have shrunk it if we had 929 * allocated it before the malloc. 930 */ 931 if ((error = fdalloc(p, 0, &i))) { 932 nfiles--; 933 FREE(fp, M_FILE); 934 return (error); 935 } 936 fp->f_count = 1; 937 fp->f_cred = p->p_ucred; 938 fp->f_ops = &badfileops; 939 fp->f_seqcount = 1; 940 crhold(fp->f_cred); 941 if ((fq = p->p_fd->fd_ofiles[0])) { 942 LIST_INSERT_AFTER(fq, fp, f_list); 943 } else { 944 LIST_INSERT_HEAD(&filehead, fp, f_list); 945 } 946 p->p_fd->fd_ofiles[i] = fp; 947 if (resultfp) 948 *resultfp = fp; 949 if (resultfd) 950 *resultfd = i; 951 return (0); 952 } 953 954 /* 955 * Free a file descriptor. 956 */ 957 void 958 ffree(fp) 959 register struct file *fp; 960 { 961 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 962 LIST_REMOVE(fp, f_list); 963 crfree(fp->f_cred); 964 nfiles--; 965 FREE(fp, M_FILE); 966 } 967 968 /* 969 * Build a new filedesc structure. 970 */ 971 struct filedesc * 972 fdinit(p) 973 struct proc *p; 974 { 975 register struct filedesc0 *newfdp; 976 register struct filedesc *fdp = p->p_fd; 977 978 MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0), 979 M_FILEDESC, M_WAITOK); 980 bzero(newfdp, sizeof(struct filedesc0)); 981 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 982 if (newfdp->fd_fd.fd_cdir) 983 VREF(newfdp->fd_fd.fd_cdir); 984 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 985 if (newfdp->fd_fd.fd_rdir) 986 VREF(newfdp->fd_fd.fd_rdir); 987 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 988 if (newfdp->fd_fd.fd_jdir) 989 VREF(newfdp->fd_fd.fd_jdir); 990 991 /* Create the file descriptor table. */ 992 newfdp->fd_fd.fd_refcnt = 1; 993 newfdp->fd_fd.fd_cmask = cmask; 994 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 995 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 996 newfdp->fd_fd.fd_nfiles = NDFILE; 997 newfdp->fd_fd.fd_knlistsize = -1; 998 999 return (&newfdp->fd_fd); 1000 } 1001 1002 /* 1003 * Share a filedesc structure. 1004 */ 1005 struct filedesc * 1006 fdshare(p) 1007 struct proc *p; 1008 { 1009 p->p_fd->fd_refcnt++; 1010 return (p->p_fd); 1011 } 1012 1013 /* 1014 * Copy a filedesc structure. 1015 */ 1016 struct filedesc * 1017 fdcopy(p) 1018 struct proc *p; 1019 { 1020 register struct filedesc *newfdp, *fdp = p->p_fd; 1021 register struct file **fpp; 1022 register int i; 1023 1024 /* Certain daemons might not have file descriptors. */ 1025 if (fdp == NULL) 1026 return (NULL); 1027 1028 MALLOC(newfdp, struct filedesc *, sizeof(struct filedesc0), 1029 M_FILEDESC, M_WAITOK); 1030 bcopy(fdp, newfdp, sizeof(struct filedesc)); 1031 if (newfdp->fd_cdir) 1032 VREF(newfdp->fd_cdir); 1033 if (newfdp->fd_rdir) 1034 VREF(newfdp->fd_rdir); 1035 if (newfdp->fd_jdir) 1036 VREF(newfdp->fd_jdir); 1037 newfdp->fd_refcnt = 1; 1038 1039 /* 1040 * If the number of open files fits in the internal arrays 1041 * of the open file structure, use them, otherwise allocate 1042 * additional memory for the number of descriptors currently 1043 * in use. 1044 */ 1045 if (newfdp->fd_lastfile < NDFILE) { 1046 newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles; 1047 newfdp->fd_ofileflags = 1048 ((struct filedesc0 *) newfdp)->fd_dfileflags; 1049 i = NDFILE; 1050 } else { 1051 /* 1052 * Compute the smallest multiple of NDEXTENT needed 1053 * for the file descriptors currently in use, 1054 * allowing the table to shrink. 1055 */ 1056 i = newfdp->fd_nfiles; 1057 while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2) 1058 i /= 2; 1059 MALLOC(newfdp->fd_ofiles, struct file **, i * OFILESIZE, 1060 M_FILEDESC, M_WAITOK); 1061 newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i]; 1062 } 1063 newfdp->fd_nfiles = i; 1064 bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **)); 1065 bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char)); 1066 1067 /* 1068 * kq descriptors cannot be copied. 1069 */ 1070 if (newfdp->fd_knlistsize != -1) { 1071 fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile]; 1072 for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) { 1073 if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) { 1074 *fpp = NULL; 1075 if (i < newfdp->fd_freefile) 1076 newfdp->fd_freefile = i; 1077 } 1078 if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0) 1079 newfdp->fd_lastfile--; 1080 } 1081 newfdp->fd_knlist = NULL; 1082 newfdp->fd_knlistsize = -1; 1083 newfdp->fd_knhash = NULL; 1084 newfdp->fd_knhashmask = 0; 1085 } 1086 1087 fpp = newfdp->fd_ofiles; 1088 for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) { 1089 if (*fpp != NULL) 1090 fhold(*fpp); 1091 } 1092 return (newfdp); 1093 } 1094 1095 /* 1096 * Release a filedesc structure. 1097 */ 1098 void 1099 fdfree(p) 1100 struct proc *p; 1101 { 1102 register struct filedesc *fdp = p->p_fd; 1103 struct file **fpp; 1104 register int i; 1105 struct filedesc_to_leader *fdtol; 1106 struct file *fp; 1107 struct vnode *vp; 1108 struct flock lf; 1109 1110 /* Certain daemons might not have file descriptors. */ 1111 if (fdp == NULL) 1112 return; 1113 1114 /* Check for special need to clear POSIX style locks */ 1115 fdtol = p->p_fdtol; 1116 if (fdtol != NULL) { 1117 KASSERT(fdtol->fdl_refcount > 0, 1118 ("filedesc_to_refcount botch: fdl_refcount=%d", 1119 fdtol->fdl_refcount)); 1120 if (fdtol->fdl_refcount == 1 && 1121 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1122 i = 0; 1123 fpp = fdp->fd_ofiles; 1124 for (i = 0, fpp = fdp->fd_ofiles; 1125 i <= fdp->fd_lastfile; 1126 i++, fpp++) { 1127 if (*fpp == NULL || 1128 (*fpp)->f_type != DTYPE_VNODE) 1129 continue; 1130 fp = *fpp; 1131 fhold(fp); 1132 lf.l_whence = SEEK_SET; 1133 lf.l_start = 0; 1134 lf.l_len = 0; 1135 lf.l_type = F_UNLCK; 1136 vp = (struct vnode *)fp->f_data; 1137 (void) VOP_ADVLOCK(vp, 1138 (caddr_t)p->p_leader, 1139 F_UNLCK, 1140 &lf, 1141 F_POSIX); 1142 fdrop(fp, p); 1143 fpp = fdp->fd_ofiles + i; 1144 } 1145 } 1146 retry: 1147 if (fdtol->fdl_refcount == 1) { 1148 if (fdp->fd_holdleaderscount > 0 && 1149 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 1150 /* 1151 * close() or do_dup() has cleared a reference 1152 * in a shared file descriptor table. 1153 */ 1154 fdp->fd_holdleaderswakeup = 1; 1155 tsleep(&fdp->fd_holdleaderscount, 1156 PLOCK, "fdlhold", 0); 1157 goto retry; 1158 } 1159 if (fdtol->fdl_holdcount > 0) { 1160 /* 1161 * Ensure that fdtol->fdl_leader 1162 * remains valid in closef(). 1163 */ 1164 fdtol->fdl_wakeup = 1; 1165 tsleep(fdtol, PLOCK, "fdlhold", 0); 1166 goto retry; 1167 } 1168 } 1169 fdtol->fdl_refcount--; 1170 if (fdtol->fdl_refcount == 0 && 1171 fdtol->fdl_holdcount == 0) { 1172 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1173 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1174 } else 1175 fdtol = NULL; 1176 p->p_fdtol = NULL; 1177 if (fdtol != NULL) 1178 FREE(fdtol, M_FILEDESC_TO_LEADER); 1179 } 1180 if (--fdp->fd_refcnt > 0) 1181 return; 1182 /* 1183 * we are the last reference to the structure, we can 1184 * safely assume it will not change out from under us. 1185 */ 1186 fpp = fdp->fd_ofiles; 1187 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1188 if (*fpp) 1189 (void) closef(*fpp, p); 1190 } 1191 if (fdp->fd_nfiles > NDFILE) 1192 FREE(fdp->fd_ofiles, M_FILEDESC); 1193 if (fdp->fd_cdir) 1194 vrele(fdp->fd_cdir); 1195 if (fdp->fd_rdir) 1196 vrele(fdp->fd_rdir); 1197 if (fdp->fd_jdir) 1198 vrele(fdp->fd_jdir); 1199 if (fdp->fd_knlist) 1200 FREE(fdp->fd_knlist, M_KQUEUE); 1201 if (fdp->fd_knhash) 1202 FREE(fdp->fd_knhash, M_KQUEUE); 1203 FREE(fdp, M_FILEDESC); 1204 } 1205 1206 /* 1207 * For setugid programs, we don't want to people to use that setugidness 1208 * to generate error messages which write to a file which otherwise would 1209 * otherwise be off-limits to the process. 1210 * 1211 * This is a gross hack to plug the hole. A better solution would involve 1212 * a special vop or other form of generalized access control mechanism. We 1213 * go ahead and just reject all procfs file systems accesses as dangerous. 1214 * 1215 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1216 * sufficient. We also don't for check setugidness since we know we are. 1217 */ 1218 static int 1219 is_unsafe(struct file *fp) 1220 { 1221 if (fp->f_type == DTYPE_VNODE && 1222 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 1223 return (1); 1224 return (0); 1225 } 1226 1227 /* 1228 * Make this setguid thing safe, if at all possible. 1229 */ 1230 void 1231 setugidsafety(p) 1232 struct proc *p; 1233 { 1234 struct filedesc *fdp = p->p_fd; 1235 register int i; 1236 1237 /* Certain daemons might not have file descriptors. */ 1238 if (fdp == NULL) 1239 return; 1240 1241 /* 1242 * note: fdp->fd_ofiles may be reallocated out from under us while 1243 * we are blocked in a close. Be careful! 1244 */ 1245 for (i = 0; i <= fdp->fd_lastfile; i++) { 1246 if (i > 2) 1247 break; 1248 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1249 struct file *fp; 1250 1251 #if 0 1252 if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0) 1253 (void) munmapfd(p, i); 1254 #endif 1255 if (i < fdp->fd_knlistsize) 1256 knote_fdclose(p, i); 1257 /* 1258 * NULL-out descriptor prior to close to avoid 1259 * a race while close blocks. 1260 */ 1261 fp = fdp->fd_ofiles[i]; 1262 fdp->fd_ofiles[i] = NULL; 1263 fdp->fd_ofileflags[i] = 0; 1264 if (i < fdp->fd_freefile) 1265 fdp->fd_freefile = i; 1266 (void) closef(fp, p); 1267 } 1268 } 1269 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1270 fdp->fd_lastfile--; 1271 } 1272 1273 /* 1274 * Close any files on exec? 1275 */ 1276 void 1277 fdcloseexec(p) 1278 struct proc *p; 1279 { 1280 struct filedesc *fdp = p->p_fd; 1281 register int i; 1282 1283 /* Certain daemons might not have file descriptors. */ 1284 if (fdp == NULL) 1285 return; 1286 1287 /* 1288 * We cannot cache fd_ofiles or fd_ofileflags since operations 1289 * may block and rip them out from under us. 1290 */ 1291 for (i = 0; i <= fdp->fd_lastfile; i++) { 1292 if (fdp->fd_ofiles[i] != NULL && 1293 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1294 struct file *fp; 1295 1296 #if 0 1297 if (fdp->fd_ofileflags[i] & UF_MAPPED) 1298 (void) munmapfd(p, i); 1299 #endif 1300 if (i < fdp->fd_knlistsize) 1301 knote_fdclose(p, i); 1302 /* 1303 * NULL-out descriptor prior to close to avoid 1304 * a race while close blocks. 1305 */ 1306 fp = fdp->fd_ofiles[i]; 1307 fdp->fd_ofiles[i] = NULL; 1308 fdp->fd_ofileflags[i] = 0; 1309 if (i < fdp->fd_freefile) 1310 fdp->fd_freefile = i; 1311 (void) closef(fp, p); 1312 } 1313 } 1314 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL) 1315 fdp->fd_lastfile--; 1316 } 1317 1318 /* 1319 * It is unsafe for set[ug]id processes to be started with file 1320 * descriptors 0..2 closed, as these descriptors are given implicit 1321 * significance in the Standard C library. fdcheckstd() will create a 1322 * descriptor referencing /dev/null for each of stdin, stdout, and 1323 * stderr that is not already open. 1324 */ 1325 int 1326 fdcheckstd(p) 1327 struct proc *p; 1328 { 1329 struct nameidata nd; 1330 struct filedesc *fdp; 1331 struct file *fp; 1332 register_t retval; 1333 int fd, i, error, flags, devnull; 1334 1335 fdp = p->p_fd; 1336 if (fdp == NULL) 1337 return (0); 1338 devnull = -1; 1339 error = 0; 1340 for (i = 0; i < 3; i++) { 1341 if (fdp->fd_ofiles[i] != NULL) 1342 continue; 1343 if (devnull < 0) { 1344 error = falloc(p, &fp, &fd); 1345 if (error != 0) 1346 break; 1347 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null", 1348 p); 1349 flags = FREAD | FWRITE; 1350 error = vn_open(&nd, flags, 0); 1351 if (error != 0) { 1352 fdp->fd_ofiles[i] = NULL; 1353 fdrop(fp, p); 1354 break; 1355 } 1356 NDFREE(&nd, NDF_ONLY_PNBUF); 1357 fp->f_data = (caddr_t)nd.ni_vp; 1358 fp->f_flag = flags; 1359 fp->f_ops = &vnops; 1360 fp->f_type = DTYPE_VNODE; 1361 VOP_UNLOCK(nd.ni_vp, 0, p); 1362 devnull = fd; 1363 } else { 1364 error = fdalloc(p, 0, &fd); 1365 if (error != 0) 1366 break; 1367 error = do_dup(fdp, devnull, fd, &retval, p); 1368 if (error != 0) 1369 break; 1370 } 1371 } 1372 return (error); 1373 } 1374 1375 /* 1376 * Internal form of close. 1377 * Decrement reference count on file structure. 1378 * Note: p may be NULL when closing a file 1379 * that was being passed in a message. 1380 */ 1381 int 1382 closef(fp, p) 1383 register struct file *fp; 1384 register struct proc *p; 1385 { 1386 struct vnode *vp; 1387 struct flock lf; 1388 struct filedesc_to_leader *fdtol; 1389 1390 if (fp == NULL) 1391 return (0); 1392 /* 1393 * POSIX record locking dictates that any close releases ALL 1394 * locks owned by this process. This is handled by setting 1395 * a flag in the unlock to free ONLY locks obeying POSIX 1396 * semantics, and not to free BSD-style file locks. 1397 * If the descriptor was in a message, POSIX-style locks 1398 * aren't passed with the descriptor. 1399 */ 1400 if (p != NULL && 1401 fp->f_type == DTYPE_VNODE) { 1402 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) { 1403 lf.l_whence = SEEK_SET; 1404 lf.l_start = 0; 1405 lf.l_len = 0; 1406 lf.l_type = F_UNLCK; 1407 vp = (struct vnode *)fp->f_data; 1408 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 1409 &lf, F_POSIX); 1410 } 1411 fdtol = p->p_fdtol; 1412 if (fdtol != NULL) { 1413 /* 1414 * Handle special case where file descriptor table 1415 * is shared between multiple process leaders. 1416 */ 1417 for (fdtol = fdtol->fdl_next; 1418 fdtol != p->p_fdtol; 1419 fdtol = fdtol->fdl_next) { 1420 if ((fdtol->fdl_leader->p_flag & 1421 P_ADVLOCK) == 0) 1422 continue; 1423 fdtol->fdl_holdcount++; 1424 lf.l_whence = SEEK_SET; 1425 lf.l_start = 0; 1426 lf.l_len = 0; 1427 lf.l_type = F_UNLCK; 1428 vp = (struct vnode *)fp->f_data; 1429 (void) VOP_ADVLOCK(vp, 1430 (caddr_t)p->p_leader, 1431 F_UNLCK, &lf, F_POSIX); 1432 fdtol->fdl_holdcount--; 1433 if (fdtol->fdl_holdcount == 0 && 1434 fdtol->fdl_wakeup != 0) { 1435 fdtol->fdl_wakeup = 0; 1436 wakeup(fdtol); 1437 } 1438 } 1439 } 1440 } 1441 return (fdrop(fp, p)); 1442 } 1443 1444 int 1445 fdrop(fp, p) 1446 struct file *fp; 1447 struct proc *p; 1448 { 1449 struct flock lf; 1450 struct vnode *vp; 1451 int error; 1452 1453 if (--fp->f_count > 0) 1454 return (0); 1455 if (fp->f_count < 0) 1456 panic("fdrop: count < 0"); 1457 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 1458 lf.l_whence = SEEK_SET; 1459 lf.l_start = 0; 1460 lf.l_len = 0; 1461 lf.l_type = F_UNLCK; 1462 vp = (struct vnode *)fp->f_data; 1463 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 1464 } 1465 if (fp->f_ops != &badfileops) 1466 error = fo_close(fp, p); 1467 else 1468 error = 0; 1469 ffree(fp); 1470 return (error); 1471 } 1472 1473 /* 1474 * Apply an advisory lock on a file descriptor. 1475 * 1476 * Just attempt to get a record lock of the requested type on 1477 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 1478 */ 1479 #ifndef _SYS_SYSPROTO_H_ 1480 struct flock_args { 1481 int fd; 1482 int how; 1483 }; 1484 #endif 1485 /* ARGSUSED */ 1486 int 1487 flock(p, uap) 1488 struct proc *p; 1489 register struct flock_args *uap; 1490 { 1491 register struct filedesc *fdp = p->p_fd; 1492 register struct file *fp; 1493 struct vnode *vp; 1494 struct flock lf; 1495 1496 if ((unsigned)uap->fd >= fdp->fd_nfiles || 1497 (fp = fdp->fd_ofiles[uap->fd]) == NULL) 1498 return (EBADF); 1499 if (fp->f_type != DTYPE_VNODE) 1500 return (EOPNOTSUPP); 1501 vp = (struct vnode *)fp->f_data; 1502 lf.l_whence = SEEK_SET; 1503 lf.l_start = 0; 1504 lf.l_len = 0; 1505 if (uap->how & LOCK_UN) { 1506 lf.l_type = F_UNLCK; 1507 fp->f_flag &= ~FHASLOCK; 1508 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK)); 1509 } 1510 if (uap->how & LOCK_EX) 1511 lf.l_type = F_WRLCK; 1512 else if (uap->how & LOCK_SH) 1513 lf.l_type = F_RDLCK; 1514 else 1515 return (EBADF); 1516 fp->f_flag |= FHASLOCK; 1517 if (uap->how & LOCK_NB) 1518 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK)); 1519 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT)); 1520 } 1521 1522 /* 1523 * File Descriptor pseudo-device driver (/dev/fd/). 1524 * 1525 * Opening minor device N dup()s the file (if any) connected to file 1526 * descriptor N belonging to the calling process. Note that this driver 1527 * consists of only the ``open()'' routine, because all subsequent 1528 * references to this file will be direct to the other driver. 1529 */ 1530 /* ARGSUSED */ 1531 static int 1532 fdopen(dev, mode, type, p) 1533 dev_t dev; 1534 int mode, type; 1535 struct proc *p; 1536 { 1537 1538 /* 1539 * XXX Kludge: set curproc->p_dupfd to contain the value of the 1540 * the file descriptor being sought for duplication. The error 1541 * return ensures that the vnode for this device will be released 1542 * by vn_open. Open will detect this special error and take the 1543 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 1544 * will simply report the error. 1545 */ 1546 p->p_dupfd = minor(dev); 1547 return (ENODEV); 1548 } 1549 1550 /* 1551 * Duplicate the specified descriptor to a free descriptor. 1552 */ 1553 int 1554 dupfdopen(p, fdp, indx, dfd, mode, error) 1555 struct proc *p; 1556 struct filedesc *fdp; 1557 int indx, dfd; 1558 int mode; 1559 int error; 1560 { 1561 register struct file *wfp; 1562 struct file *fp; 1563 1564 /* 1565 * If the to-be-dup'd fd number is greater than the allowed number 1566 * of file descriptors, or the fd to be dup'd has already been 1567 * closed, then reject. 1568 */ 1569 if ((u_int)dfd >= fdp->fd_nfiles || 1570 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 1571 return (EBADF); 1572 } 1573 1574 /* 1575 * There are two cases of interest here. 1576 * 1577 * For ENODEV simply dup (dfd) to file descriptor 1578 * (indx) and return. 1579 * 1580 * For ENXIO steal away the file structure from (dfd) and 1581 * store it in (indx). (dfd) is effectively closed by 1582 * this operation. 1583 * 1584 * Any other error code is just returned. 1585 */ 1586 switch (error) { 1587 case ENODEV: 1588 /* 1589 * Check that the mode the file is being opened for is a 1590 * subset of the mode of the existing descriptor. 1591 */ 1592 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) 1593 return (EACCES); 1594 fp = fdp->fd_ofiles[indx]; 1595 #if 0 1596 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1597 (void) munmapfd(p, indx); 1598 #endif 1599 fdp->fd_ofiles[indx] = wfp; 1600 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1601 fhold(wfp); 1602 if (indx > fdp->fd_lastfile) 1603 fdp->fd_lastfile = indx; 1604 /* 1605 * we now own the reference to fp that the ofiles[] array 1606 * used to own. Release it. 1607 */ 1608 if (fp) 1609 fdrop(fp, p); 1610 return (0); 1611 1612 case ENXIO: 1613 /* 1614 * Steal away the file pointer from dfd, and stuff it into indx. 1615 */ 1616 fp = fdp->fd_ofiles[indx]; 1617 #if 0 1618 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED) 1619 (void) munmapfd(p, indx); 1620 #endif 1621 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 1622 fdp->fd_ofiles[dfd] = NULL; 1623 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 1624 fdp->fd_ofileflags[dfd] = 0; 1625 1626 /* 1627 * we now own the reference to fp that the ofiles[] array 1628 * used to own. Release it. 1629 */ 1630 if (fp) 1631 fdrop(fp, p); 1632 /* 1633 * Complete the clean up of the filedesc structure by 1634 * recomputing the various hints. 1635 */ 1636 if (indx > fdp->fd_lastfile) { 1637 fdp->fd_lastfile = indx; 1638 } else { 1639 while (fdp->fd_lastfile > 0 && 1640 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) { 1641 fdp->fd_lastfile--; 1642 } 1643 if (dfd < fdp->fd_freefile) 1644 fdp->fd_freefile = dfd; 1645 } 1646 return (0); 1647 1648 default: 1649 return (error); 1650 } 1651 /* NOTREACHED */ 1652 } 1653 1654 1655 struct filedesc_to_leader * 1656 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 1657 struct proc *leader) 1658 { 1659 struct filedesc_to_leader *fdtol; 1660 1661 MALLOC(fdtol, struct filedesc_to_leader *, 1662 sizeof(struct filedesc_to_leader), 1663 M_FILEDESC_TO_LEADER, 1664 M_WAITOK); 1665 fdtol->fdl_refcount = 1; 1666 fdtol->fdl_holdcount = 0; 1667 fdtol->fdl_wakeup = 0; 1668 fdtol->fdl_leader = leader; 1669 if (old != NULL) { 1670 fdtol->fdl_next = old->fdl_next; 1671 fdtol->fdl_prev = old; 1672 old->fdl_next = fdtol; 1673 fdtol->fdl_next->fdl_prev = fdtol; 1674 } else { 1675 fdtol->fdl_next = fdtol; 1676 fdtol->fdl_prev = fdtol; 1677 } 1678 return fdtol; 1679 } 1680 1681 /* 1682 * Get file structures. 1683 */ 1684 static int 1685 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 1686 { 1687 int error; 1688 struct file *fp; 1689 1690 if (!req->oldptr) { 1691 /* 1692 * overestimate by 10 files 1693 */ 1694 return (SYSCTL_OUT(req, 0, sizeof(filehead) + 1695 (nfiles + 10) * sizeof(struct file))); 1696 } 1697 1698 error = SYSCTL_OUT(req, (caddr_t)&filehead, sizeof(filehead)); 1699 if (error) 1700 return (error); 1701 1702 /* 1703 * followed by an array of file structures 1704 */ 1705 LIST_FOREACH(fp, &filehead, f_list) { 1706 error = SYSCTL_OUT(req, (caddr_t)fp, sizeof (struct file)); 1707 if (error) 1708 return (error); 1709 } 1710 return (0); 1711 } 1712 1713 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 1714 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 1715 1716 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 1717 &maxfilesperproc, 0, "Maximum files allowed open per process"); 1718 1719 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 1720 &maxfiles, 0, "Maximum number of files"); 1721 1722 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 1723 &nfiles, 0, "System-wide number of open files"); 1724 1725 static void 1726 fildesc_drvinit(void *unused) 1727 { 1728 int fd; 1729 1730 for (fd = 0; fd < NUMFDESC; fd++) 1731 make_dev(&fildesc_cdevsw, fd, 1732 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 1733 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 1734 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 1735 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 1736 } 1737 1738 struct fileops badfileops = { 1739 badfo_readwrite, 1740 badfo_readwrite, 1741 badfo_ioctl, 1742 badfo_poll, 1743 badfo_kqfilter, 1744 badfo_stat, 1745 badfo_close 1746 }; 1747 1748 static int 1749 badfo_readwrite(fp, uio, cred, flags, p) 1750 struct file *fp; 1751 struct uio *uio; 1752 struct ucred *cred; 1753 struct proc *p; 1754 int flags; 1755 { 1756 1757 return (EBADF); 1758 } 1759 1760 static int 1761 badfo_ioctl(fp, com, data, p) 1762 struct file *fp; 1763 u_long com; 1764 caddr_t data; 1765 struct proc *p; 1766 { 1767 1768 return (EBADF); 1769 } 1770 1771 static int 1772 badfo_poll(fp, events, cred, p) 1773 struct file *fp; 1774 int events; 1775 struct ucred *cred; 1776 struct proc *p; 1777 { 1778 1779 return (0); 1780 } 1781 1782 static int 1783 badfo_kqfilter(fp, kn) 1784 struct file *fp; 1785 struct knote *kn; 1786 { 1787 1788 return (0); 1789 } 1790 1791 static int 1792 badfo_stat(fp, sb, p) 1793 struct file *fp; 1794 struct stat *sb; 1795 struct proc *p; 1796 { 1797 1798 return (EBADF); 1799 } 1800 1801 static int 1802 badfo_close(fp, p) 1803 struct file *fp; 1804 struct proc *p; 1805 { 1806 1807 return (EBADF); 1808 } 1809 1810 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 1811 fildesc_drvinit,NULL)
Cache object: 898ad5abdc0f4cfaae80f3d7f996868d
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