1 /* 2 * Copyright (c) 2005 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Jeffrey Hsu. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * 35 * Copyright (c) 1982, 1986, 1989, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 68 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $ 69 */ 70 71 #include "opt_compat.h" 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/malloc.h> 75 #include <sys/sysproto.h> 76 #include <sys/conf.h> 77 #include <sys/device.h> 78 #include <sys/file.h> 79 #include <sys/filedesc.h> 80 #include <sys/kernel.h> 81 #include <sys/sysctl.h> 82 #include <sys/vnode.h> 83 #include <sys/proc.h> 84 #include <sys/nlookup.h> 85 #include <sys/stat.h> 86 #include <sys/filio.h> 87 #include <sys/fcntl.h> 88 #include <sys/unistd.h> 89 #include <sys/resourcevar.h> 90 #include <sys/event.h> 91 #include <sys/kern_syscall.h> 92 #include <sys/kcore.h> 93 #include <sys/kinfo.h> 94 #include <sys/un.h> 95 96 #include <vm/vm.h> 97 #include <vm/vm_extern.h> 98 99 #include <sys/thread2.h> 100 #include <sys/file2.h> 101 #include <sys/spinlock2.h> 102 103 static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd); 104 static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr); 105 static struct file *funsetfd_locked (struct filedesc *fdp, int fd); 106 static void ffree(struct file *fp); 107 108 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 109 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 110 "file desc to leader structures"); 111 MALLOC_DEFINE(M_FILE, "file", "Open file structure"); 112 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 113 114 static struct krate krate_uidinfo = { .freq = 1 }; 115 116 static d_open_t fdopen; 117 #define NUMFDESC 64 118 119 #define CDEV_MAJOR 22 120 static struct dev_ops fildesc_ops = { 121 { "FD", 0, 0 }, 122 .d_open = fdopen, 123 }; 124 125 /* 126 * Descriptor management. 127 */ 128 static struct filelist filehead = LIST_HEAD_INITIALIZER(&filehead); 129 static struct spinlock filehead_spin = SPINLOCK_INITIALIZER(&filehead_spin); 130 static int nfiles; /* actual number of open files */ 131 extern int cmask; 132 133 /* 134 * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared. 135 * 136 * MPSAFE - must be called with fdp->fd_spin exclusively held 137 */ 138 static __inline 139 void 140 fdfixup_locked(struct filedesc *fdp, int fd) 141 { 142 if (fd < fdp->fd_freefile) { 143 fdp->fd_freefile = fd; 144 } 145 while (fdp->fd_lastfile >= 0 && 146 fdp->fd_files[fdp->fd_lastfile].fp == NULL && 147 fdp->fd_files[fdp->fd_lastfile].reserved == 0 148 ) { 149 --fdp->fd_lastfile; 150 } 151 } 152 153 /* 154 * System calls on descriptors. 155 * 156 * MPSAFE 157 */ 158 int 159 sys_getdtablesize(struct getdtablesize_args *uap) 160 { 161 struct proc *p = curproc; 162 struct plimit *limit = p->p_limit; 163 int dtsize; 164 165 spin_lock(&limit->p_spin); 166 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 167 dtsize = INT_MAX; 168 else 169 dtsize = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 170 spin_unlock(&limit->p_spin); 171 172 if (dtsize > maxfilesperproc) 173 dtsize = maxfilesperproc; 174 if (dtsize < minfilesperproc) 175 dtsize = minfilesperproc; 176 if (p->p_ucred->cr_uid && dtsize > maxfilesperuser) 177 dtsize = maxfilesperuser; 178 uap->sysmsg_result = dtsize; 179 return (0); 180 } 181 182 /* 183 * Duplicate a file descriptor to a particular value. 184 * 185 * note: keep in mind that a potential race condition exists when closing 186 * descriptors from a shared descriptor table (via rfork). 187 * 188 * MPSAFE 189 */ 190 int 191 sys_dup2(struct dup2_args *uap) 192 { 193 int error; 194 int fd = 0; 195 196 error = kern_dup(DUP_FIXED, uap->from, uap->to, &fd); 197 uap->sysmsg_fds[0] = fd; 198 199 return (error); 200 } 201 202 /* 203 * Duplicate a file descriptor. 204 * 205 * MPSAFE 206 */ 207 int 208 sys_dup(struct dup_args *uap) 209 { 210 int error; 211 int fd = 0; 212 213 error = kern_dup(DUP_VARIABLE, uap->fd, 0, &fd); 214 uap->sysmsg_fds[0] = fd; 215 216 return (error); 217 } 218 219 /* 220 * MPALMOSTSAFE - acquires mplock for fp operations 221 */ 222 int 223 kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred) 224 { 225 struct thread *td = curthread; 226 struct proc *p = td->td_proc; 227 struct file *fp; 228 struct vnode *vp; 229 u_int newmin; 230 u_int oflags; 231 u_int nflags; 232 int tmp, error, flg = F_POSIX; 233 234 KKASSERT(p); 235 236 /* 237 * Operations on file descriptors that do not require a file pointer. 238 */ 239 switch (cmd) { 240 case F_GETFD: 241 error = fgetfdflags(p->p_fd, fd, &tmp); 242 if (error == 0) 243 dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0; 244 return (error); 245 246 case F_SETFD: 247 if (dat->fc_cloexec & FD_CLOEXEC) 248 error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE); 249 else 250 error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE); 251 return (error); 252 case F_DUPFD: 253 newmin = dat->fc_fd; 254 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); 255 return (error); 256 case F_DUP2FD: 257 newmin = dat->fc_fd; 258 error = kern_dup(DUP_FIXED, fd, newmin, &dat->fc_fd); 259 return (error); 260 case F_DUPFD_CLOEXEC: 261 newmin = dat->fc_fd; 262 error = kern_dup(DUP_VARIABLE | DUP_CLOEXEC, fd, newmin, 263 &dat->fc_fd); 264 return (error); 265 case F_DUP2FD_CLOEXEC: 266 newmin = dat->fc_fd; 267 error = kern_dup(DUP_FIXED | DUP_CLOEXEC, fd, newmin, 268 &dat->fc_fd); 269 return (error); 270 default: 271 break; 272 } 273 274 /* 275 * Operations on file pointers 276 */ 277 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 278 return (EBADF); 279 280 switch (cmd) { 281 case F_GETFL: 282 dat->fc_flags = OFLAGS(fp->f_flag); 283 error = 0; 284 break; 285 286 case F_SETFL: 287 oflags = fp->f_flag; 288 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 289 nflags |= oflags & ~FCNTLFLAGS; 290 291 error = 0; 292 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) 293 error = EINVAL; 294 if (error == 0 && ((nflags ^ oflags) & FASYNC)) { 295 tmp = nflags & FASYNC; 296 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, 297 cred, NULL); 298 } 299 if (error == 0) 300 fp->f_flag = nflags; 301 break; 302 303 case F_GETOWN: 304 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, 305 cred, NULL); 306 break; 307 308 case F_SETOWN: 309 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, 310 cred, NULL); 311 break; 312 313 case F_SETLKW: 314 flg |= F_WAIT; 315 /* Fall into F_SETLK */ 316 317 case F_SETLK: 318 if (fp->f_type != DTYPE_VNODE) { 319 error = EBADF; 320 break; 321 } 322 vp = (struct vnode *)fp->f_data; 323 324 /* 325 * copyin/lockop may block 326 */ 327 if (dat->fc_flock.l_whence == SEEK_CUR) 328 dat->fc_flock.l_start += fp->f_offset; 329 330 switch (dat->fc_flock.l_type) { 331 case F_RDLCK: 332 if ((fp->f_flag & FREAD) == 0) { 333 error = EBADF; 334 break; 335 } 336 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 337 lwkt_gettoken(&p->p_leader->p_token); 338 p->p_leader->p_flags |= P_ADVLOCK; 339 lwkt_reltoken(&p->p_leader->p_token); 340 } 341 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 342 &dat->fc_flock, flg); 343 break; 344 case F_WRLCK: 345 if ((fp->f_flag & FWRITE) == 0) { 346 error = EBADF; 347 break; 348 } 349 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 350 lwkt_gettoken(&p->p_leader->p_token); 351 p->p_leader->p_flags |= P_ADVLOCK; 352 lwkt_reltoken(&p->p_leader->p_token); 353 } 354 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 355 &dat->fc_flock, flg); 356 break; 357 case F_UNLCK: 358 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 359 &dat->fc_flock, F_POSIX); 360 break; 361 default: 362 error = EINVAL; 363 break; 364 } 365 366 /* 367 * It is possible to race a close() on the descriptor while 368 * we were blocked getting the lock. If this occurs the 369 * close might not have caught the lock. 370 */ 371 if (checkfdclosed(p->p_fd, fd, fp)) { 372 dat->fc_flock.l_whence = SEEK_SET; 373 dat->fc_flock.l_start = 0; 374 dat->fc_flock.l_len = 0; 375 dat->fc_flock.l_type = F_UNLCK; 376 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 377 F_UNLCK, &dat->fc_flock, F_POSIX); 378 } 379 break; 380 381 case F_GETLK: 382 if (fp->f_type != DTYPE_VNODE) { 383 error = EBADF; 384 break; 385 } 386 vp = (struct vnode *)fp->f_data; 387 /* 388 * copyin/lockop may block 389 */ 390 if (dat->fc_flock.l_type != F_RDLCK && 391 dat->fc_flock.l_type != F_WRLCK && 392 dat->fc_flock.l_type != F_UNLCK) { 393 error = EINVAL; 394 break; 395 } 396 if (dat->fc_flock.l_whence == SEEK_CUR) 397 dat->fc_flock.l_start += fp->f_offset; 398 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 399 &dat->fc_flock, F_POSIX); 400 break; 401 default: 402 error = EINVAL; 403 break; 404 } 405 406 fdrop(fp); 407 return (error); 408 } 409 410 /* 411 * The file control system call. 412 * 413 * MPSAFE 414 */ 415 int 416 sys_fcntl(struct fcntl_args *uap) 417 { 418 union fcntl_dat dat; 419 int error; 420 421 switch (uap->cmd) { 422 case F_DUPFD: 423 case F_DUP2FD: 424 case F_DUPFD_CLOEXEC: 425 case F_DUP2FD_CLOEXEC: 426 dat.fc_fd = uap->arg; 427 break; 428 case F_SETFD: 429 dat.fc_cloexec = uap->arg; 430 break; 431 case F_SETFL: 432 dat.fc_flags = uap->arg; 433 break; 434 case F_SETOWN: 435 dat.fc_owner = uap->arg; 436 break; 437 case F_SETLKW: 438 case F_SETLK: 439 case F_GETLK: 440 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 441 sizeof(struct flock)); 442 if (error) 443 return (error); 444 break; 445 } 446 447 error = kern_fcntl(uap->fd, uap->cmd, &dat, curthread->td_ucred); 448 449 if (error == 0) { 450 switch (uap->cmd) { 451 case F_DUPFD: 452 case F_DUP2FD: 453 case F_DUPFD_CLOEXEC: 454 case F_DUP2FD_CLOEXEC: 455 uap->sysmsg_result = dat.fc_fd; 456 break; 457 case F_GETFD: 458 uap->sysmsg_result = dat.fc_cloexec; 459 break; 460 case F_GETFL: 461 uap->sysmsg_result = dat.fc_flags; 462 break; 463 case F_GETOWN: 464 uap->sysmsg_result = dat.fc_owner; 465 break; 466 case F_GETLK: 467 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 468 sizeof(struct flock)); 469 break; 470 } 471 } 472 473 return (error); 474 } 475 476 /* 477 * Common code for dup, dup2, and fcntl(F_DUPFD). 478 * 479 * There are three type flags: DUP_FIXED, DUP_VARIABLE, and DUP_CLOEXEC. 480 * The first two flags are mutually exclusive, and the third is optional. 481 * DUP_FIXED tells kern_dup() to destructively dup over an existing file 482 * descriptor if "new" is already open. DUP_VARIABLE tells kern_dup() 483 * to find the lowest unused file descriptor that is greater than or 484 * equal to "new". DUP_CLOEXEC, which works with either of the first 485 * two flags, sets the close-on-exec flag on the "new" file descriptor. 486 * 487 * MPSAFE 488 */ 489 int 490 kern_dup(int flags, int old, int new, int *res) 491 { 492 struct thread *td = curthread; 493 struct proc *p = td->td_proc; 494 struct filedesc *fdp = p->p_fd; 495 struct file *fp; 496 struct file *delfp; 497 int oldflags; 498 int holdleaders; 499 int dtsize; 500 int error, newfd; 501 502 /* 503 * Verify that we have a valid descriptor to dup from and 504 * possibly to dup to. 505 * 506 * NOTE: maxfilesperuser is not applicable to dup() 507 */ 508 retry: 509 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 510 dtsize = INT_MAX; 511 else 512 dtsize = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 513 if (dtsize > maxfilesperproc) 514 dtsize = maxfilesperproc; 515 if (dtsize < minfilesperproc) 516 dtsize = minfilesperproc; 517 518 if (new < 0 || new > dtsize) 519 return (EINVAL); 520 521 spin_lock(&fdp->fd_spin); 522 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { 523 spin_unlock(&fdp->fd_spin); 524 return (EBADF); 525 } 526 if ((flags & DUP_FIXED) && old == new) { 527 *res = new; 528 if (flags & DUP_CLOEXEC) 529 fdp->fd_files[new].fileflags |= UF_EXCLOSE; 530 spin_unlock(&fdp->fd_spin); 531 return (0); 532 } 533 fp = fdp->fd_files[old].fp; 534 oldflags = fdp->fd_files[old].fileflags; 535 fhold(fp); /* MPSAFE - can be called with a spinlock held */ 536 537 /* 538 * Allocate a new descriptor if DUP_VARIABLE, or expand the table 539 * if the requested descriptor is beyond the current table size. 540 * 541 * This can block. Retry if the source descriptor no longer matches 542 * or if our expectation in the expansion case races. 543 * 544 * If we are not expanding or allocating a new decriptor, then reset 545 * the target descriptor to a reserved state so we have a uniform 546 * setup for the next code block. 547 */ 548 if ((flags & DUP_VARIABLE) || new >= fdp->fd_nfiles) { 549 spin_unlock(&fdp->fd_spin); 550 error = fdalloc(p, new, &newfd); 551 spin_lock(&fdp->fd_spin); 552 if (error) { 553 spin_unlock(&fdp->fd_spin); 554 fdrop(fp); 555 return (error); 556 } 557 /* 558 * Check for ripout 559 */ 560 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { 561 fsetfd_locked(fdp, NULL, newfd); 562 spin_unlock(&fdp->fd_spin); 563 fdrop(fp); 564 goto retry; 565 } 566 /* 567 * Check for expansion race 568 */ 569 if ((flags & DUP_VARIABLE) == 0 && new != newfd) { 570 fsetfd_locked(fdp, NULL, newfd); 571 spin_unlock(&fdp->fd_spin); 572 fdrop(fp); 573 goto retry; 574 } 575 /* 576 * Check for ripout, newfd reused old (this case probably 577 * can't occur). 578 */ 579 if (old == newfd) { 580 fsetfd_locked(fdp, NULL, newfd); 581 spin_unlock(&fdp->fd_spin); 582 fdrop(fp); 583 goto retry; 584 } 585 new = newfd; 586 delfp = NULL; 587 } else { 588 if (fdp->fd_files[new].reserved) { 589 spin_unlock(&fdp->fd_spin); 590 fdrop(fp); 591 kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new); 592 tsleep(fdp, 0, "fdres", hz); 593 goto retry; 594 } 595 596 /* 597 * If the target descriptor was never allocated we have 598 * to allocate it. If it was we have to clean out the 599 * old descriptor. delfp inherits the ref from the 600 * descriptor table. 601 */ 602 delfp = fdp->fd_files[new].fp; 603 fdp->fd_files[new].fp = NULL; 604 fdp->fd_files[new].reserved = 1; 605 if (delfp == NULL) { 606 fdreserve_locked(fdp, new, 1); 607 if (new > fdp->fd_lastfile) 608 fdp->fd_lastfile = new; 609 } 610 611 } 612 613 /* 614 * NOTE: still holding an exclusive spinlock 615 */ 616 617 /* 618 * If a descriptor is being overwritten we may hve to tell 619 * fdfree() to sleep to ensure that all relevant process 620 * leaders can be traversed in closef(). 621 */ 622 if (delfp != NULL && p->p_fdtol != NULL) { 623 fdp->fd_holdleaderscount++; 624 holdleaders = 1; 625 } else { 626 holdleaders = 0; 627 } 628 KASSERT(delfp == NULL || (flags & DUP_FIXED), 629 ("dup() picked an open file")); 630 631 /* 632 * Duplicate the source descriptor, update lastfile. If the new 633 * descriptor was not allocated and we aren't replacing an existing 634 * descriptor we have to mark the descriptor as being in use. 635 * 636 * The fd_files[] array inherits fp's hold reference. 637 */ 638 fsetfd_locked(fdp, fp, new); 639 if ((flags & DUP_CLOEXEC) != 0) 640 fdp->fd_files[new].fileflags = oldflags | UF_EXCLOSE; 641 else 642 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; 643 spin_unlock(&fdp->fd_spin); 644 fdrop(fp); 645 *res = new; 646 647 /* 648 * If we dup'd over a valid file, we now own the reference to it 649 * and must dispose of it using closef() semantics (as if a 650 * close() were performed on it). 651 */ 652 if (delfp) { 653 if (SLIST_FIRST(&delfp->f_klist)) 654 knote_fdclose(delfp, fdp, new); 655 closef(delfp, p); 656 if (holdleaders) { 657 spin_lock(&fdp->fd_spin); 658 fdp->fd_holdleaderscount--; 659 if (fdp->fd_holdleaderscount == 0 && 660 fdp->fd_holdleaderswakeup != 0) { 661 fdp->fd_holdleaderswakeup = 0; 662 spin_unlock(&fdp->fd_spin); 663 wakeup(&fdp->fd_holdleaderscount); 664 } else { 665 spin_unlock(&fdp->fd_spin); 666 } 667 } 668 } 669 return (0); 670 } 671 672 /* 673 * If sigio is on the list associated with a process or process group, 674 * disable signalling from the device, remove sigio from the list and 675 * free sigio. 676 * 677 * MPSAFE 678 */ 679 void 680 funsetown(struct sigio **sigiop) 681 { 682 struct pgrp *pgrp; 683 struct proc *p; 684 struct sigio *sigio; 685 686 if ((sigio = *sigiop) != NULL) { 687 lwkt_gettoken(&sigio_token); /* protect sigio */ 688 KKASSERT(sigiop == sigio->sio_myref); 689 sigio = *sigiop; 690 *sigiop = NULL; 691 lwkt_reltoken(&sigio_token); 692 } 693 if (sigio == NULL) 694 return; 695 696 if (sigio->sio_pgid < 0) { 697 pgrp = sigio->sio_pgrp; 698 sigio->sio_pgrp = NULL; 699 lwkt_gettoken(&pgrp->pg_token); 700 SLIST_REMOVE(&pgrp->pg_sigiolst, sigio, sigio, sio_pgsigio); 701 lwkt_reltoken(&pgrp->pg_token); 702 pgrel(pgrp); 703 } else /* if ((*sigiop)->sio_pgid > 0) */ { 704 p = sigio->sio_proc; 705 sigio->sio_proc = NULL; 706 PHOLD(p); 707 lwkt_gettoken(&p->p_token); 708 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, sio_pgsigio); 709 lwkt_reltoken(&p->p_token); 710 PRELE(p); 711 } 712 crfree(sigio->sio_ucred); 713 sigio->sio_ucred = NULL; 714 kfree(sigio, M_SIGIO); 715 } 716 717 /* 718 * Free a list of sigio structures. Caller is responsible for ensuring 719 * that the list is MPSAFE. 720 * 721 * MPSAFE 722 */ 723 void 724 funsetownlst(struct sigiolst *sigiolst) 725 { 726 struct sigio *sigio; 727 728 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 729 funsetown(sigio->sio_myref); 730 } 731 732 /* 733 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 734 * 735 * After permission checking, add a sigio structure to the sigio list for 736 * the process or process group. 737 * 738 * MPSAFE 739 */ 740 int 741 fsetown(pid_t pgid, struct sigio **sigiop) 742 { 743 struct proc *proc = NULL; 744 struct pgrp *pgrp = NULL; 745 struct sigio *sigio; 746 int error; 747 748 if (pgid == 0) { 749 funsetown(sigiop); 750 return (0); 751 } 752 753 if (pgid > 0) { 754 proc = pfind(pgid); 755 if (proc == NULL) { 756 error = ESRCH; 757 goto done; 758 } 759 760 /* 761 * Policy - Don't allow a process to FSETOWN a process 762 * in another session. 763 * 764 * Remove this test to allow maximum flexibility or 765 * restrict FSETOWN to the current process or process 766 * group for maximum safety. 767 */ 768 if (proc->p_session != curproc->p_session) { 769 error = EPERM; 770 goto done; 771 } 772 } else /* if (pgid < 0) */ { 773 pgrp = pgfind(-pgid); 774 if (pgrp == NULL) { 775 error = ESRCH; 776 goto done; 777 } 778 779 /* 780 * Policy - Don't allow a process to FSETOWN a process 781 * in another session. 782 * 783 * Remove this test to allow maximum flexibility or 784 * restrict FSETOWN to the current process or process 785 * group for maximum safety. 786 */ 787 if (pgrp->pg_session != curproc->p_session) { 788 error = EPERM; 789 goto done; 790 } 791 } 792 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK | M_ZERO); 793 if (pgid > 0) { 794 KKASSERT(pgrp == NULL); 795 lwkt_gettoken(&proc->p_token); 796 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 797 sigio->sio_proc = proc; 798 lwkt_reltoken(&proc->p_token); 799 } else { 800 KKASSERT(proc == NULL); 801 lwkt_gettoken(&pgrp->pg_token); 802 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 803 sigio->sio_pgrp = pgrp; 804 lwkt_reltoken(&pgrp->pg_token); 805 pgrp = NULL; 806 } 807 sigio->sio_pgid = pgid; 808 sigio->sio_ucred = crhold(curthread->td_ucred); 809 /* It would be convenient if p_ruid was in ucred. */ 810 sigio->sio_ruid = sigio->sio_ucred->cr_ruid; 811 sigio->sio_myref = sigiop; 812 813 lwkt_gettoken(&sigio_token); 814 while (*sigiop) 815 funsetown(sigiop); 816 *sigiop = sigio; 817 lwkt_reltoken(&sigio_token); 818 error = 0; 819 done: 820 if (pgrp) 821 pgrel(pgrp); 822 if (proc) 823 PRELE(proc); 824 return (error); 825 } 826 827 /* 828 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 829 * 830 * MPSAFE 831 */ 832 pid_t 833 fgetown(struct sigio **sigiop) 834 { 835 struct sigio *sigio; 836 pid_t own; 837 838 lwkt_gettoken_shared(&sigio_token); 839 sigio = *sigiop; 840 own = (sigio != NULL ? sigio->sio_pgid : 0); 841 lwkt_reltoken(&sigio_token); 842 843 return (own); 844 } 845 846 /* 847 * Close many file descriptors. 848 * 849 * MPSAFE 850 */ 851 int 852 sys_closefrom(struct closefrom_args *uap) 853 { 854 return(kern_closefrom(uap->fd)); 855 } 856 857 /* 858 * Close all file descriptors greater then or equal to fd 859 * 860 * MPSAFE 861 */ 862 int 863 kern_closefrom(int fd) 864 { 865 struct thread *td = curthread; 866 struct proc *p = td->td_proc; 867 struct filedesc *fdp; 868 869 KKASSERT(p); 870 fdp = p->p_fd; 871 872 if (fd < 0) 873 return (EINVAL); 874 875 /* 876 * NOTE: This function will skip unassociated descriptors and 877 * reserved descriptors that have not yet been assigned. 878 * fd_lastfile can change as a side effect of kern_close(). 879 */ 880 spin_lock(&fdp->fd_spin); 881 while (fd <= fdp->fd_lastfile) { 882 if (fdp->fd_files[fd].fp != NULL) { 883 spin_unlock(&fdp->fd_spin); 884 /* ok if this races another close */ 885 if (kern_close(fd) == EINTR) 886 return (EINTR); 887 spin_lock(&fdp->fd_spin); 888 } 889 ++fd; 890 } 891 spin_unlock(&fdp->fd_spin); 892 return (0); 893 } 894 895 /* 896 * Close a file descriptor. 897 * 898 * MPSAFE 899 */ 900 int 901 sys_close(struct close_args *uap) 902 { 903 return(kern_close(uap->fd)); 904 } 905 906 /* 907 * MPSAFE 908 */ 909 int 910 kern_close(int fd) 911 { 912 struct thread *td = curthread; 913 struct proc *p = td->td_proc; 914 struct filedesc *fdp; 915 struct file *fp; 916 int error; 917 int holdleaders; 918 919 KKASSERT(p); 920 fdp = p->p_fd; 921 922 spin_lock(&fdp->fd_spin); 923 if ((fp = funsetfd_locked(fdp, fd)) == NULL) { 924 spin_unlock(&fdp->fd_spin); 925 return (EBADF); 926 } 927 holdleaders = 0; 928 if (p->p_fdtol != NULL) { 929 /* 930 * Ask fdfree() to sleep to ensure that all relevant 931 * process leaders can be traversed in closef(). 932 */ 933 fdp->fd_holdleaderscount++; 934 holdleaders = 1; 935 } 936 937 /* 938 * we now hold the fp reference that used to be owned by the descriptor 939 * array. 940 */ 941 spin_unlock(&fdp->fd_spin); 942 if (SLIST_FIRST(&fp->f_klist)) 943 knote_fdclose(fp, fdp, fd); 944 error = closef(fp, p); 945 if (holdleaders) { 946 spin_lock(&fdp->fd_spin); 947 fdp->fd_holdleaderscount--; 948 if (fdp->fd_holdleaderscount == 0 && 949 fdp->fd_holdleaderswakeup != 0) { 950 fdp->fd_holdleaderswakeup = 0; 951 spin_unlock(&fdp->fd_spin); 952 wakeup(&fdp->fd_holdleaderscount); 953 } else { 954 spin_unlock(&fdp->fd_spin); 955 } 956 } 957 return (error); 958 } 959 960 /* 961 * shutdown_args(int fd, int how) 962 */ 963 int 964 kern_shutdown(int fd, int how) 965 { 966 struct thread *td = curthread; 967 struct proc *p = td->td_proc; 968 struct file *fp; 969 int error; 970 971 KKASSERT(p); 972 973 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 974 return (EBADF); 975 error = fo_shutdown(fp, how); 976 fdrop(fp); 977 978 return (error); 979 } 980 981 /* 982 * MPALMOSTSAFE 983 */ 984 int 985 sys_shutdown(struct shutdown_args *uap) 986 { 987 int error; 988 989 error = kern_shutdown(uap->s, uap->how); 990 991 return (error); 992 } 993 994 /* 995 * MPSAFE 996 */ 997 int 998 kern_fstat(int fd, struct stat *ub) 999 { 1000 struct thread *td = curthread; 1001 struct proc *p = td->td_proc; 1002 struct file *fp; 1003 int error; 1004 1005 KKASSERT(p); 1006 1007 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 1008 return (EBADF); 1009 error = fo_stat(fp, ub, td->td_ucred); 1010 fdrop(fp); 1011 1012 return (error); 1013 } 1014 1015 /* 1016 * Return status information about a file descriptor. 1017 * 1018 * MPSAFE 1019 */ 1020 int 1021 sys_fstat(struct fstat_args *uap) 1022 { 1023 struct stat st; 1024 int error; 1025 1026 error = kern_fstat(uap->fd, &st); 1027 1028 if (error == 0) 1029 error = copyout(&st, uap->sb, sizeof(st)); 1030 return (error); 1031 } 1032 1033 /* 1034 * Return pathconf information about a file descriptor. 1035 * 1036 * MPALMOSTSAFE 1037 */ 1038 int 1039 sys_fpathconf(struct fpathconf_args *uap) 1040 { 1041 struct thread *td = curthread; 1042 struct proc *p = td->td_proc; 1043 struct file *fp; 1044 struct vnode *vp; 1045 int error = 0; 1046 1047 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 1048 return (EBADF); 1049 1050 switch (fp->f_type) { 1051 case DTYPE_PIPE: 1052 case DTYPE_SOCKET: 1053 if (uap->name != _PC_PIPE_BUF) { 1054 error = EINVAL; 1055 } else { 1056 uap->sysmsg_result = PIPE_BUF; 1057 error = 0; 1058 } 1059 break; 1060 case DTYPE_FIFO: 1061 case DTYPE_VNODE: 1062 vp = (struct vnode *)fp->f_data; 1063 error = VOP_PATHCONF(vp, uap->name, &uap->sysmsg_reg); 1064 break; 1065 default: 1066 error = EOPNOTSUPP; 1067 break; 1068 } 1069 fdrop(fp); 1070 return(error); 1071 } 1072 1073 static int fdexpand; 1074 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, 1075 "Number of times a file table has been expanded"); 1076 1077 /* 1078 * Grow the file table so it can hold through descriptor (want). 1079 * 1080 * The fdp's spinlock must be held exclusively on entry and may be held 1081 * exclusively on return. The spinlock may be cycled by the routine. 1082 * 1083 * MPSAFE 1084 */ 1085 static void 1086 fdgrow_locked(struct filedesc *fdp, int want) 1087 { 1088 struct fdnode *newfiles; 1089 struct fdnode *oldfiles; 1090 int nf, extra; 1091 1092 nf = fdp->fd_nfiles; 1093 do { 1094 /* nf has to be of the form 2^n - 1 */ 1095 nf = 2 * nf + 1; 1096 } while (nf <= want); 1097 1098 spin_unlock(&fdp->fd_spin); 1099 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); 1100 spin_lock(&fdp->fd_spin); 1101 1102 /* 1103 * We could have raced another extend while we were not holding 1104 * the spinlock. 1105 */ 1106 if (fdp->fd_nfiles >= nf) { 1107 spin_unlock(&fdp->fd_spin); 1108 kfree(newfiles, M_FILEDESC); 1109 spin_lock(&fdp->fd_spin); 1110 return; 1111 } 1112 /* 1113 * Copy the existing ofile and ofileflags arrays 1114 * and zero the new portion of each array. 1115 */ 1116 extra = nf - fdp->fd_nfiles; 1117 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); 1118 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); 1119 1120 oldfiles = fdp->fd_files; 1121 fdp->fd_files = newfiles; 1122 fdp->fd_nfiles = nf; 1123 1124 if (oldfiles != fdp->fd_builtin_files) { 1125 spin_unlock(&fdp->fd_spin); 1126 kfree(oldfiles, M_FILEDESC); 1127 spin_lock(&fdp->fd_spin); 1128 } 1129 fdexpand++; 1130 } 1131 1132 /* 1133 * Number of nodes in right subtree, including the root. 1134 */ 1135 static __inline int 1136 right_subtree_size(int n) 1137 { 1138 return (n ^ (n | (n + 1))); 1139 } 1140 1141 /* 1142 * Bigger ancestor. 1143 */ 1144 static __inline int 1145 right_ancestor(int n) 1146 { 1147 return (n | (n + 1)); 1148 } 1149 1150 /* 1151 * Smaller ancestor. 1152 */ 1153 static __inline int 1154 left_ancestor(int n) 1155 { 1156 return ((n & (n + 1)) - 1); 1157 } 1158 1159 /* 1160 * Traverse the in-place binary tree buttom-up adjusting the allocation 1161 * count so scans can determine where free descriptors are located. 1162 * 1163 * MPSAFE - caller must be holding an exclusive spinlock on fdp 1164 */ 1165 static 1166 void 1167 fdreserve_locked(struct filedesc *fdp, int fd, int incr) 1168 { 1169 while (fd >= 0) { 1170 fdp->fd_files[fd].allocated += incr; 1171 KKASSERT(fdp->fd_files[fd].allocated >= 0); 1172 fd = left_ancestor(fd); 1173 } 1174 } 1175 1176 /* 1177 * Reserve a file descriptor for the process. If no error occurs, the 1178 * caller MUST at some point call fsetfd() or assign a file pointer 1179 * or dispose of the reservation. 1180 * 1181 * MPSAFE 1182 */ 1183 int 1184 fdalloc(struct proc *p, int want, int *result) 1185 { 1186 struct filedesc *fdp = p->p_fd; 1187 struct uidinfo *uip; 1188 int fd, rsize, rsum, node, lim; 1189 1190 /* 1191 * Check dtable size limit 1192 */ 1193 spin_lock(&p->p_limit->p_spin); 1194 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1195 lim = INT_MAX; 1196 else 1197 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1198 spin_unlock(&p->p_limit->p_spin); 1199 1200 if (lim > maxfilesperproc) 1201 lim = maxfilesperproc; 1202 if (lim < minfilesperproc) 1203 lim = minfilesperproc; 1204 if (want >= lim) 1205 return (EMFILE); 1206 1207 /* 1208 * Check that the user has not run out of descriptors (non-root only). 1209 * As a safety measure the dtable is allowed to have at least 1210 * minfilesperproc open fds regardless of the maxfilesperuser limit. 1211 */ 1212 if (p->p_ucred->cr_uid && fdp->fd_nfiles >= minfilesperproc) { 1213 uip = p->p_ucred->cr_uidinfo; 1214 if (uip->ui_openfiles > maxfilesperuser) { 1215 krateprintf(&krate_uidinfo, 1216 "Warning: user %d pid %d (%s) ran out of " 1217 "file descriptors (%d/%d)\n", 1218 p->p_ucred->cr_uid, (int)p->p_pid, 1219 p->p_comm, 1220 uip->ui_openfiles, maxfilesperuser); 1221 return(ENFILE); 1222 } 1223 } 1224 1225 /* 1226 * Grow the dtable if necessary 1227 */ 1228 spin_lock(&fdp->fd_spin); 1229 if (want >= fdp->fd_nfiles) 1230 fdgrow_locked(fdp, want); 1231 1232 /* 1233 * Search for a free descriptor starting at the higher 1234 * of want or fd_freefile. If that fails, consider 1235 * expanding the ofile array. 1236 * 1237 * NOTE! the 'allocated' field is a cumulative recursive allocation 1238 * count. If we happen to see a value of 0 then we can shortcut 1239 * our search. Otherwise we run through through the tree going 1240 * down branches we know have free descriptor(s) until we hit a 1241 * leaf node. The leaf node will be free but will not necessarily 1242 * have an allocated field of 0. 1243 */ 1244 retry: 1245 /* move up the tree looking for a subtree with a free node */ 1246 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); 1247 fd = right_ancestor(fd)) { 1248 if (fdp->fd_files[fd].allocated == 0) 1249 goto found; 1250 1251 rsize = right_subtree_size(fd); 1252 if (fdp->fd_files[fd].allocated == rsize) 1253 continue; /* right subtree full */ 1254 1255 /* 1256 * Free fd is in the right subtree of the tree rooted at fd. 1257 * Call that subtree R. Look for the smallest (leftmost) 1258 * subtree of R with an unallocated fd: continue moving 1259 * down the left branch until encountering a full left 1260 * subtree, then move to the right. 1261 */ 1262 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 1263 node = fd + rsize; 1264 rsum += fdp->fd_files[node].allocated; 1265 if (fdp->fd_files[fd].allocated == rsum + rsize) { 1266 fd = node; /* move to the right */ 1267 if (fdp->fd_files[node].allocated == 0) 1268 goto found; 1269 rsum = 0; 1270 } 1271 } 1272 goto found; 1273 } 1274 1275 /* 1276 * No space in current array. Expand? 1277 */ 1278 if (fdp->fd_nfiles >= lim) { 1279 spin_unlock(&fdp->fd_spin); 1280 return (EMFILE); 1281 } 1282 fdgrow_locked(fdp, want); 1283 goto retry; 1284 1285 found: 1286 KKASSERT(fd < fdp->fd_nfiles); 1287 if (fd > fdp->fd_lastfile) 1288 fdp->fd_lastfile = fd; 1289 if (want <= fdp->fd_freefile) 1290 fdp->fd_freefile = fd; 1291 *result = fd; 1292 KKASSERT(fdp->fd_files[fd].fp == NULL); 1293 KKASSERT(fdp->fd_files[fd].reserved == 0); 1294 fdp->fd_files[fd].fileflags = 0; 1295 fdp->fd_files[fd].reserved = 1; 1296 fdreserve_locked(fdp, fd, 1); 1297 spin_unlock(&fdp->fd_spin); 1298 return (0); 1299 } 1300 1301 /* 1302 * Check to see whether n user file descriptors 1303 * are available to the process p. 1304 * 1305 * MPSAFE 1306 */ 1307 int 1308 fdavail(struct proc *p, int n) 1309 { 1310 struct filedesc *fdp = p->p_fd; 1311 struct fdnode *fdnode; 1312 int i, lim, last; 1313 1314 spin_lock(&p->p_limit->p_spin); 1315 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1316 lim = INT_MAX; 1317 else 1318 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1319 spin_unlock(&p->p_limit->p_spin); 1320 1321 if (lim > maxfilesperproc) 1322 lim = maxfilesperproc; 1323 if (lim < minfilesperproc) 1324 lim = minfilesperproc; 1325 1326 spin_lock(&fdp->fd_spin); 1327 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { 1328 spin_unlock(&fdp->fd_spin); 1329 return (1); 1330 } 1331 last = min(fdp->fd_nfiles, lim); 1332 fdnode = &fdp->fd_files[fdp->fd_freefile]; 1333 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { 1334 if (fdnode->fp == NULL && --n <= 0) { 1335 spin_unlock(&fdp->fd_spin); 1336 return (1); 1337 } 1338 } 1339 spin_unlock(&fdp->fd_spin); 1340 return (0); 1341 } 1342 1343 /* 1344 * Revoke open descriptors referencing (f_data, f_type) 1345 * 1346 * Any revoke executed within a prison is only able to 1347 * revoke descriptors for processes within that prison. 1348 * 1349 * Returns 0 on success or an error code. 1350 */ 1351 struct fdrevoke_info { 1352 void *data; 1353 short type; 1354 short unused; 1355 int count; 1356 int intransit; 1357 struct ucred *cred; 1358 struct file *nfp; 1359 }; 1360 1361 static int fdrevoke_check_callback(struct file *fp, void *vinfo); 1362 static int fdrevoke_proc_callback(struct proc *p, void *vinfo); 1363 1364 int 1365 fdrevoke(void *f_data, short f_type, struct ucred *cred) 1366 { 1367 struct fdrevoke_info info; 1368 int error; 1369 1370 bzero(&info, sizeof(info)); 1371 info.data = f_data; 1372 info.type = f_type; 1373 info.cred = cred; 1374 error = falloc(NULL, &info.nfp, NULL); 1375 if (error) 1376 return (error); 1377 1378 /* 1379 * Scan the file pointer table once. dups do not dup file pointers, 1380 * only descriptors, so there is no leak. Set FREVOKED on the fps 1381 * being revoked. 1382 */ 1383 allfiles_scan_exclusive(fdrevoke_check_callback, &info); 1384 1385 /* 1386 * If any fps were marked track down the related descriptors 1387 * and close them. Any dup()s at this point will notice 1388 * the FREVOKED already set in the fp and do the right thing. 1389 * 1390 * Any fps with non-zero msgcounts (aka sent over a unix-domain 1391 * socket) bumped the intransit counter and will require a 1392 * scan. Races against fps leaving the socket are closed by 1393 * the socket code checking for FREVOKED. 1394 */ 1395 if (info.count) 1396 allproc_scan(fdrevoke_proc_callback, &info); 1397 if (info.intransit) 1398 unp_revoke_gc(info.nfp); 1399 fdrop(info.nfp); 1400 return(0); 1401 } 1402 1403 /* 1404 * Locate matching file pointers directly. 1405 * 1406 * WARNING: allfiles_scan_exclusive() holds a spinlock through these calls! 1407 */ 1408 static int 1409 fdrevoke_check_callback(struct file *fp, void *vinfo) 1410 { 1411 struct fdrevoke_info *info = vinfo; 1412 1413 /* 1414 * File pointers already flagged for revokation are skipped. 1415 */ 1416 if (fp->f_flag & FREVOKED) 1417 return(0); 1418 1419 /* 1420 * If revoking from a prison file pointers created outside of 1421 * that prison, or file pointers without creds, cannot be revoked. 1422 */ 1423 if (info->cred->cr_prison && 1424 (fp->f_cred == NULL || 1425 info->cred->cr_prison != fp->f_cred->cr_prison)) { 1426 return(0); 1427 } 1428 1429 /* 1430 * If the file pointer matches then mark it for revocation. The 1431 * flag is currently only used by unp_revoke_gc(). 1432 * 1433 * info->count is a heuristic and can race in a SMP environment. 1434 */ 1435 if (info->data == fp->f_data && info->type == fp->f_type) { 1436 atomic_set_int(&fp->f_flag, FREVOKED); 1437 info->count += fp->f_count; 1438 if (fp->f_msgcount) 1439 ++info->intransit; 1440 } 1441 return(0); 1442 } 1443 1444 /* 1445 * Locate matching file pointers via process descriptor tables. 1446 */ 1447 static int 1448 fdrevoke_proc_callback(struct proc *p, void *vinfo) 1449 { 1450 struct fdrevoke_info *info = vinfo; 1451 struct filedesc *fdp; 1452 struct file *fp; 1453 int n; 1454 1455 if (p->p_stat == SIDL || p->p_stat == SZOMB) 1456 return(0); 1457 if (info->cred->cr_prison && 1458 info->cred->cr_prison != p->p_ucred->cr_prison) { 1459 return(0); 1460 } 1461 1462 /* 1463 * If the controlling terminal of the process matches the 1464 * vnode being revoked we clear the controlling terminal. 1465 * 1466 * The normal spec_close() may not catch this because it 1467 * uses curproc instead of p. 1468 */ 1469 if (p->p_session && info->type == DTYPE_VNODE && 1470 info->data == p->p_session->s_ttyvp) { 1471 p->p_session->s_ttyvp = NULL; 1472 vrele(info->data); 1473 } 1474 1475 /* 1476 * Softref the fdp to prevent it from being destroyed 1477 */ 1478 spin_lock(&p->p_spin); 1479 if ((fdp = p->p_fd) == NULL) { 1480 spin_unlock(&p->p_spin); 1481 return(0); 1482 } 1483 atomic_add_int(&fdp->fd_softrefs, 1); 1484 spin_unlock(&p->p_spin); 1485 1486 /* 1487 * Locate and close any matching file descriptors. 1488 */ 1489 spin_lock(&fdp->fd_spin); 1490 for (n = 0; n < fdp->fd_nfiles; ++n) { 1491 if ((fp = fdp->fd_files[n].fp) == NULL) 1492 continue; 1493 if (fp->f_flag & FREVOKED) { 1494 fhold(info->nfp); 1495 fdp->fd_files[n].fp = info->nfp; 1496 spin_unlock(&fdp->fd_spin); 1497 knote_fdclose(fp, fdp, n); /* XXX */ 1498 closef(fp, p); 1499 spin_lock(&fdp->fd_spin); 1500 --info->count; 1501 } 1502 } 1503 spin_unlock(&fdp->fd_spin); 1504 atomic_subtract_int(&fdp->fd_softrefs, 1); 1505 return(0); 1506 } 1507 1508 /* 1509 * falloc: 1510 * Create a new open file structure and reserve a file decriptor 1511 * for the process that refers to it. 1512 * 1513 * Root creds are checked using lp, or assumed if lp is NULL. If 1514 * resultfd is non-NULL then lp must also be non-NULL. No file 1515 * descriptor is reserved (and no process context is needed) if 1516 * resultfd is NULL. 1517 * 1518 * A file pointer with a refcount of 1 is returned. Note that the 1519 * file pointer is NOT associated with the descriptor. If falloc 1520 * returns success, fsetfd() MUST be called to either associate the 1521 * file pointer or clear the reservation. 1522 * 1523 * MPSAFE 1524 */ 1525 int 1526 falloc(struct lwp *lp, struct file **resultfp, int *resultfd) 1527 { 1528 static struct timeval lastfail; 1529 static int curfail; 1530 struct file *fp; 1531 struct ucred *cred = lp ? lp->lwp_thread->td_ucred : proc0.p_ucred; 1532 int error; 1533 1534 fp = NULL; 1535 1536 /* 1537 * Handle filetable full issues and root overfill. 1538 */ 1539 if (nfiles >= maxfiles - maxfilesrootres && 1540 (cred->cr_ruid != 0 || nfiles >= maxfiles)) { 1541 if (ppsratecheck(&lastfail, &curfail, 1)) { 1542 kprintf("kern.maxfiles limit exceeded by uid %d, " 1543 "please see tuning(7).\n", 1544 cred->cr_ruid); 1545 } 1546 error = ENFILE; 1547 goto done; 1548 } 1549 1550 /* 1551 * Allocate a new file descriptor. 1552 */ 1553 fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 1554 spin_init(&fp->f_spin); 1555 SLIST_INIT(&fp->f_klist); 1556 fp->f_count = 1; 1557 fp->f_ops = &badfileops; 1558 fp->f_seqcount = 1; 1559 fsetcred(fp, cred); 1560 spin_lock(&filehead_spin); 1561 nfiles++; 1562 LIST_INSERT_HEAD(&filehead, fp, f_list); 1563 spin_unlock(&filehead_spin); 1564 if (resultfd) { 1565 if ((error = fdalloc(lp->lwp_proc, 0, resultfd)) != 0) { 1566 fdrop(fp); 1567 fp = NULL; 1568 } 1569 } else { 1570 error = 0; 1571 } 1572 done: 1573 *resultfp = fp; 1574 return (error); 1575 } 1576 1577 /* 1578 * Check for races against a file descriptor by determining that the 1579 * file pointer is still associated with the specified file descriptor, 1580 * and a close is not currently in progress. 1581 * 1582 * MPSAFE 1583 */ 1584 int 1585 checkfdclosed(struct filedesc *fdp, int fd, struct file *fp) 1586 { 1587 int error; 1588 1589 spin_lock_shared(&fdp->fd_spin); 1590 if ((unsigned)fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) 1591 error = EBADF; 1592 else 1593 error = 0; 1594 spin_unlock_shared(&fdp->fd_spin); 1595 return (error); 1596 } 1597 1598 /* 1599 * Associate a file pointer with a previously reserved file descriptor. 1600 * This function always succeeds. 1601 * 1602 * If fp is NULL, the file descriptor is returned to the pool. 1603 */ 1604 1605 /* 1606 * MPSAFE (exclusive spinlock must be held on call) 1607 */ 1608 static void 1609 fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) 1610 { 1611 KKASSERT((unsigned)fd < fdp->fd_nfiles); 1612 KKASSERT(fdp->fd_files[fd].reserved != 0); 1613 if (fp) { 1614 fhold(fp); 1615 fdp->fd_files[fd].fp = fp; 1616 fdp->fd_files[fd].reserved = 0; 1617 } else { 1618 fdp->fd_files[fd].reserved = 0; 1619 fdreserve_locked(fdp, fd, -1); 1620 fdfixup_locked(fdp, fd); 1621 } 1622 } 1623 1624 /* 1625 * MPSAFE 1626 */ 1627 void 1628 fsetfd(struct filedesc *fdp, struct file *fp, int fd) 1629 { 1630 spin_lock(&fdp->fd_spin); 1631 fsetfd_locked(fdp, fp, fd); 1632 spin_unlock(&fdp->fd_spin); 1633 } 1634 1635 /* 1636 * MPSAFE (exclusive spinlock must be held on call) 1637 */ 1638 static 1639 struct file * 1640 funsetfd_locked(struct filedesc *fdp, int fd) 1641 { 1642 struct file *fp; 1643 1644 if ((unsigned)fd >= fdp->fd_nfiles) 1645 return (NULL); 1646 if ((fp = fdp->fd_files[fd].fp) == NULL) 1647 return (NULL); 1648 fdp->fd_files[fd].fp = NULL; 1649 fdp->fd_files[fd].fileflags = 0; 1650 1651 fdreserve_locked(fdp, fd, -1); 1652 fdfixup_locked(fdp, fd); 1653 return(fp); 1654 } 1655 1656 /* 1657 * MPSAFE 1658 */ 1659 int 1660 fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) 1661 { 1662 int error; 1663 1664 spin_lock(&fdp->fd_spin); 1665 if (((u_int)fd) >= fdp->fd_nfiles) { 1666 error = EBADF; 1667 } else if (fdp->fd_files[fd].fp == NULL) { 1668 error = EBADF; 1669 } else { 1670 *flagsp = fdp->fd_files[fd].fileflags; 1671 error = 0; 1672 } 1673 spin_unlock(&fdp->fd_spin); 1674 return (error); 1675 } 1676 1677 /* 1678 * MPSAFE 1679 */ 1680 int 1681 fsetfdflags(struct filedesc *fdp, int fd, int add_flags) 1682 { 1683 int error; 1684 1685 spin_lock(&fdp->fd_spin); 1686 if (((u_int)fd) >= fdp->fd_nfiles) { 1687 error = EBADF; 1688 } else if (fdp->fd_files[fd].fp == NULL) { 1689 error = EBADF; 1690 } else { 1691 fdp->fd_files[fd].fileflags |= add_flags; 1692 error = 0; 1693 } 1694 spin_unlock(&fdp->fd_spin); 1695 return (error); 1696 } 1697 1698 /* 1699 * MPSAFE 1700 */ 1701 int 1702 fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) 1703 { 1704 int error; 1705 1706 spin_lock(&fdp->fd_spin); 1707 if (((u_int)fd) >= fdp->fd_nfiles) { 1708 error = EBADF; 1709 } else if (fdp->fd_files[fd].fp == NULL) { 1710 error = EBADF; 1711 } else { 1712 fdp->fd_files[fd].fileflags &= ~rem_flags; 1713 error = 0; 1714 } 1715 spin_unlock(&fdp->fd_spin); 1716 return (error); 1717 } 1718 1719 /* 1720 * Set/Change/Clear the creds for a fp and synchronize the uidinfo. 1721 */ 1722 void 1723 fsetcred(struct file *fp, struct ucred *ncr) 1724 { 1725 struct ucred *ocr; 1726 struct uidinfo *uip; 1727 1728 ocr = fp->f_cred; 1729 if (ocr == NULL || ncr == NULL || ocr->cr_uidinfo != ncr->cr_uidinfo) { 1730 if (ocr) { 1731 uip = ocr->cr_uidinfo; 1732 atomic_add_int(&uip->ui_openfiles, -1); 1733 } 1734 if (ncr) { 1735 uip = ncr->cr_uidinfo; 1736 atomic_add_int(&uip->ui_openfiles, 1); 1737 } 1738 } 1739 if (ncr) 1740 crhold(ncr); 1741 fp->f_cred = ncr; 1742 if (ocr) 1743 crfree(ocr); 1744 } 1745 1746 /* 1747 * Free a file descriptor. 1748 */ 1749 static 1750 void 1751 ffree(struct file *fp) 1752 { 1753 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 1754 spin_lock(&filehead_spin); 1755 LIST_REMOVE(fp, f_list); 1756 nfiles--; 1757 spin_unlock(&filehead_spin); 1758 fsetcred(fp, NULL); 1759 if (fp->f_nchandle.ncp) 1760 cache_drop(&fp->f_nchandle); 1761 kfree(fp, M_FILE); 1762 } 1763 1764 /* 1765 * called from init_main, initialize filedesc0 for proc0. 1766 */ 1767 void 1768 fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) 1769 { 1770 p0->p_fd = fdp0; 1771 p0->p_fdtol = NULL; 1772 fdp0->fd_refcnt = 1; 1773 fdp0->fd_cmask = cmask; 1774 fdp0->fd_files = fdp0->fd_builtin_files; 1775 fdp0->fd_nfiles = NDFILE; 1776 fdp0->fd_lastfile = -1; 1777 spin_init(&fdp0->fd_spin); 1778 } 1779 1780 /* 1781 * Build a new filedesc structure. 1782 * 1783 * NOT MPSAFE (vref) 1784 */ 1785 struct filedesc * 1786 fdinit(struct proc *p) 1787 { 1788 struct filedesc *newfdp; 1789 struct filedesc *fdp = p->p_fd; 1790 1791 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); 1792 spin_lock(&fdp->fd_spin); 1793 if (fdp->fd_cdir) { 1794 newfdp->fd_cdir = fdp->fd_cdir; 1795 vref(newfdp->fd_cdir); 1796 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1797 } 1798 1799 /* 1800 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 1801 * proc0, but should unconditionally exist in other processes. 1802 */ 1803 if (fdp->fd_rdir) { 1804 newfdp->fd_rdir = fdp->fd_rdir; 1805 vref(newfdp->fd_rdir); 1806 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1807 } 1808 if (fdp->fd_jdir) { 1809 newfdp->fd_jdir = fdp->fd_jdir; 1810 vref(newfdp->fd_jdir); 1811 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1812 } 1813 spin_unlock(&fdp->fd_spin); 1814 1815 /* Create the file descriptor table. */ 1816 newfdp->fd_refcnt = 1; 1817 newfdp->fd_cmask = cmask; 1818 newfdp->fd_files = newfdp->fd_builtin_files; 1819 newfdp->fd_nfiles = NDFILE; 1820 newfdp->fd_lastfile = -1; 1821 spin_init(&newfdp->fd_spin); 1822 1823 return (newfdp); 1824 } 1825 1826 /* 1827 * Share a filedesc structure. 1828 * 1829 * MPSAFE 1830 */ 1831 struct filedesc * 1832 fdshare(struct proc *p) 1833 { 1834 struct filedesc *fdp; 1835 1836 fdp = p->p_fd; 1837 spin_lock(&fdp->fd_spin); 1838 fdp->fd_refcnt++; 1839 spin_unlock(&fdp->fd_spin); 1840 return (fdp); 1841 } 1842 1843 /* 1844 * Copy a filedesc structure. 1845 * 1846 * MPSAFE 1847 */ 1848 int 1849 fdcopy(struct proc *p, struct filedesc **fpp) 1850 { 1851 struct filedesc *fdp = p->p_fd; 1852 struct filedesc *newfdp; 1853 struct fdnode *fdnode; 1854 int i; 1855 int ni; 1856 1857 /* 1858 * Certain daemons might not have file descriptors. 1859 */ 1860 if (fdp == NULL) 1861 return (0); 1862 1863 /* 1864 * Allocate the new filedesc and fd_files[] array. This can race 1865 * with operations by other threads on the fdp so we have to be 1866 * careful. 1867 */ 1868 newfdp = kmalloc(sizeof(struct filedesc), 1869 M_FILEDESC, M_WAITOK | M_ZERO | M_NULLOK); 1870 if (newfdp == NULL) { 1871 *fpp = NULL; 1872 return (-1); 1873 } 1874 again: 1875 spin_lock(&fdp->fd_spin); 1876 if (fdp->fd_lastfile < NDFILE) { 1877 newfdp->fd_files = newfdp->fd_builtin_files; 1878 i = NDFILE; 1879 } else { 1880 /* 1881 * We have to allocate (N^2-1) entries for our in-place 1882 * binary tree. Allow the table to shrink. 1883 */ 1884 i = fdp->fd_nfiles; 1885 ni = (i - 1) / 2; 1886 while (ni > fdp->fd_lastfile && ni > NDFILE) { 1887 i = ni; 1888 ni = (i - 1) / 2; 1889 } 1890 spin_unlock(&fdp->fd_spin); 1891 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), 1892 M_FILEDESC, M_WAITOK | M_ZERO); 1893 1894 /* 1895 * Check for race, retry 1896 */ 1897 spin_lock(&fdp->fd_spin); 1898 if (i <= fdp->fd_lastfile) { 1899 spin_unlock(&fdp->fd_spin); 1900 kfree(newfdp->fd_files, M_FILEDESC); 1901 goto again; 1902 } 1903 } 1904 1905 /* 1906 * Dup the remaining fields. vref() and cache_hold() can be 1907 * safely called while holding the read spinlock on fdp. 1908 * 1909 * The read spinlock on fdp is still being held. 1910 * 1911 * NOTE: vref and cache_hold calls for the case where the vnode 1912 * or cache entry already has at least one ref may be called 1913 * while holding spin locks. 1914 */ 1915 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { 1916 vref(newfdp->fd_cdir); 1917 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1918 } 1919 /* 1920 * We must check for fd_rdir here, at least for now because 1921 * the init process is created before we have access to the 1922 * rootvode to take a reference to it. 1923 */ 1924 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { 1925 vref(newfdp->fd_rdir); 1926 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1927 } 1928 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { 1929 vref(newfdp->fd_jdir); 1930 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1931 } 1932 newfdp->fd_refcnt = 1; 1933 newfdp->fd_nfiles = i; 1934 newfdp->fd_lastfile = fdp->fd_lastfile; 1935 newfdp->fd_freefile = fdp->fd_freefile; 1936 newfdp->fd_cmask = fdp->fd_cmask; 1937 spin_init(&newfdp->fd_spin); 1938 1939 /* 1940 * Copy the descriptor table through (i). This also copies the 1941 * allocation state. Then go through and ref the file pointers 1942 * and clean up any KQ descriptors. 1943 * 1944 * kq descriptors cannot be copied. Since we haven't ref'd the 1945 * copied files yet we can ignore the return value from funsetfd(). 1946 * 1947 * The read spinlock on fdp is still being held. 1948 */ 1949 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); 1950 for (i = 0 ; i < newfdp->fd_nfiles; ++i) { 1951 fdnode = &newfdp->fd_files[i]; 1952 if (fdnode->reserved) { 1953 fdreserve_locked(newfdp, i, -1); 1954 fdnode->reserved = 0; 1955 fdfixup_locked(newfdp, i); 1956 } else if (fdnode->fp) { 1957 if (fdnode->fp->f_type == DTYPE_KQUEUE) { 1958 (void)funsetfd_locked(newfdp, i); 1959 } else { 1960 fhold(fdnode->fp); 1961 } 1962 } 1963 } 1964 spin_unlock(&fdp->fd_spin); 1965 *fpp = newfdp; 1966 return (0); 1967 } 1968 1969 /* 1970 * Release a filedesc structure. 1971 * 1972 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) 1973 */ 1974 void 1975 fdfree(struct proc *p, struct filedesc *repl) 1976 { 1977 struct filedesc *fdp; 1978 struct fdnode *fdnode; 1979 int i; 1980 struct filedesc_to_leader *fdtol; 1981 struct file *fp; 1982 struct vnode *vp; 1983 struct flock lf; 1984 1985 /* 1986 * Certain daemons might not have file descriptors. 1987 */ 1988 fdp = p->p_fd; 1989 if (fdp == NULL) { 1990 p->p_fd = repl; 1991 return; 1992 } 1993 1994 /* 1995 * Severe messing around to follow. 1996 */ 1997 spin_lock(&fdp->fd_spin); 1998 1999 /* Check for special need to clear POSIX style locks */ 2000 fdtol = p->p_fdtol; 2001 if (fdtol != NULL) { 2002 KASSERT(fdtol->fdl_refcount > 0, 2003 ("filedesc_to_refcount botch: fdl_refcount=%d", 2004 fdtol->fdl_refcount)); 2005 if (fdtol->fdl_refcount == 1 && 2006 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 2007 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2008 fdnode = &fdp->fd_files[i]; 2009 if (fdnode->fp == NULL || 2010 fdnode->fp->f_type != DTYPE_VNODE) { 2011 continue; 2012 } 2013 fp = fdnode->fp; 2014 fhold(fp); 2015 spin_unlock(&fdp->fd_spin); 2016 2017 lf.l_whence = SEEK_SET; 2018 lf.l_start = 0; 2019 lf.l_len = 0; 2020 lf.l_type = F_UNLCK; 2021 vp = (struct vnode *)fp->f_data; 2022 (void) VOP_ADVLOCK(vp, 2023 (caddr_t)p->p_leader, 2024 F_UNLCK, 2025 &lf, 2026 F_POSIX); 2027 fdrop(fp); 2028 spin_lock(&fdp->fd_spin); 2029 } 2030 } 2031 retry: 2032 if (fdtol->fdl_refcount == 1) { 2033 if (fdp->fd_holdleaderscount > 0 && 2034 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 2035 /* 2036 * close() or do_dup() has cleared a reference 2037 * in a shared file descriptor table. 2038 */ 2039 fdp->fd_holdleaderswakeup = 1; 2040 ssleep(&fdp->fd_holdleaderscount, 2041 &fdp->fd_spin, 0, "fdlhold", 0); 2042 goto retry; 2043 } 2044 if (fdtol->fdl_holdcount > 0) { 2045 /* 2046 * Ensure that fdtol->fdl_leader 2047 * remains valid in closef(). 2048 */ 2049 fdtol->fdl_wakeup = 1; 2050 ssleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); 2051 goto retry; 2052 } 2053 } 2054 fdtol->fdl_refcount--; 2055 if (fdtol->fdl_refcount == 0 && 2056 fdtol->fdl_holdcount == 0) { 2057 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2058 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2059 } else { 2060 fdtol = NULL; 2061 } 2062 p->p_fdtol = NULL; 2063 if (fdtol != NULL) { 2064 spin_unlock(&fdp->fd_spin); 2065 kfree(fdtol, M_FILEDESC_TO_LEADER); 2066 spin_lock(&fdp->fd_spin); 2067 } 2068 } 2069 if (--fdp->fd_refcnt > 0) { 2070 spin_unlock(&fdp->fd_spin); 2071 spin_lock(&p->p_spin); 2072 p->p_fd = repl; 2073 spin_unlock(&p->p_spin); 2074 return; 2075 } 2076 2077 /* 2078 * Even though we are the last reference to the structure allproc 2079 * scans may still reference the structure. Maintain proper 2080 * locks until we can replace p->p_fd. 2081 * 2082 * Also note that kqueue's closef still needs to reference the 2083 * fdp via p->p_fd, so we have to close the descriptors before 2084 * we replace p->p_fd. 2085 */ 2086 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2087 if (fdp->fd_files[i].fp) { 2088 fp = funsetfd_locked(fdp, i); 2089 if (fp) { 2090 spin_unlock(&fdp->fd_spin); 2091 if (SLIST_FIRST(&fp->f_klist)) 2092 knote_fdclose(fp, fdp, i); 2093 closef(fp, p); 2094 spin_lock(&fdp->fd_spin); 2095 } 2096 } 2097 } 2098 spin_unlock(&fdp->fd_spin); 2099 2100 /* 2101 * Interlock against an allproc scan operations (typically frevoke). 2102 */ 2103 spin_lock(&p->p_spin); 2104 p->p_fd = repl; 2105 spin_unlock(&p->p_spin); 2106 2107 /* 2108 * Wait for any softrefs to go away. This race rarely occurs so 2109 * we can use a non-critical-path style poll/sleep loop. The 2110 * race only occurs against allproc scans. 2111 * 2112 * No new softrefs can occur with the fdp disconnected from the 2113 * process. 2114 */ 2115 if (fdp->fd_softrefs) { 2116 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid); 2117 while (fdp->fd_softrefs) 2118 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1); 2119 } 2120 2121 if (fdp->fd_files != fdp->fd_builtin_files) 2122 kfree(fdp->fd_files, M_FILEDESC); 2123 if (fdp->fd_cdir) { 2124 cache_drop(&fdp->fd_ncdir); 2125 vrele(fdp->fd_cdir); 2126 } 2127 if (fdp->fd_rdir) { 2128 cache_drop(&fdp->fd_nrdir); 2129 vrele(fdp->fd_rdir); 2130 } 2131 if (fdp->fd_jdir) { 2132 cache_drop(&fdp->fd_njdir); 2133 vrele(fdp->fd_jdir); 2134 } 2135 kfree(fdp, M_FILEDESC); 2136 } 2137 2138 /* 2139 * Retrieve and reference the file pointer associated with a descriptor. 2140 * 2141 * MPSAFE 2142 */ 2143 struct file * 2144 holdfp(struct filedesc *fdp, int fd, int flag) 2145 { 2146 struct file* fp; 2147 2148 spin_lock_shared(&fdp->fd_spin); 2149 if (((u_int)fd) >= fdp->fd_nfiles) { 2150 fp = NULL; 2151 goto done; 2152 } 2153 if ((fp = fdp->fd_files[fd].fp) == NULL) 2154 goto done; 2155 if ((fp->f_flag & flag) == 0 && flag != -1) { 2156 fp = NULL; 2157 goto done; 2158 } 2159 fhold(fp); 2160 done: 2161 spin_unlock_shared(&fdp->fd_spin); 2162 return (fp); 2163 } 2164 2165 /* 2166 * holdsock() - load the struct file pointer associated 2167 * with a socket into *fpp. If an error occurs, non-zero 2168 * will be returned and *fpp will be set to NULL. 2169 * 2170 * MPSAFE 2171 */ 2172 int 2173 holdsock(struct filedesc *fdp, int fd, struct file **fpp) 2174 { 2175 struct file *fp; 2176 int error; 2177 2178 spin_lock_shared(&fdp->fd_spin); 2179 if ((unsigned)fd >= fdp->fd_nfiles) { 2180 error = EBADF; 2181 fp = NULL; 2182 goto done; 2183 } 2184 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2185 error = EBADF; 2186 goto done; 2187 } 2188 if (fp->f_type != DTYPE_SOCKET) { 2189 error = ENOTSOCK; 2190 goto done; 2191 } 2192 fhold(fp); 2193 error = 0; 2194 done: 2195 spin_unlock_shared(&fdp->fd_spin); 2196 *fpp = fp; 2197 return (error); 2198 } 2199 2200 /* 2201 * Convert a user file descriptor to a held file pointer. 2202 * 2203 * MPSAFE 2204 */ 2205 int 2206 holdvnode(struct filedesc *fdp, int fd, struct file **fpp) 2207 { 2208 struct file *fp; 2209 int error; 2210 2211 spin_lock_shared(&fdp->fd_spin); 2212 if ((unsigned)fd >= fdp->fd_nfiles) { 2213 error = EBADF; 2214 fp = NULL; 2215 goto done; 2216 } 2217 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2218 error = EBADF; 2219 goto done; 2220 } 2221 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2222 fp = NULL; 2223 error = EINVAL; 2224 goto done; 2225 } 2226 fhold(fp); 2227 error = 0; 2228 done: 2229 spin_unlock_shared(&fdp->fd_spin); 2230 *fpp = fp; 2231 return (error); 2232 } 2233 2234 /* 2235 * For setugid programs, we don't want to people to use that setugidness 2236 * to generate error messages which write to a file which otherwise would 2237 * otherwise be off-limits to the process. 2238 * 2239 * This is a gross hack to plug the hole. A better solution would involve 2240 * a special vop or other form of generalized access control mechanism. We 2241 * go ahead and just reject all procfs file systems accesses as dangerous. 2242 * 2243 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 2244 * sufficient. We also don't for check setugidness since we know we are. 2245 */ 2246 static int 2247 is_unsafe(struct file *fp) 2248 { 2249 if (fp->f_type == DTYPE_VNODE && 2250 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 2251 return (1); 2252 return (0); 2253 } 2254 2255 /* 2256 * Make this setguid thing safe, if at all possible. 2257 * 2258 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2259 */ 2260 void 2261 setugidsafety(struct proc *p) 2262 { 2263 struct filedesc *fdp = p->p_fd; 2264 int i; 2265 2266 /* Certain daemons might not have file descriptors. */ 2267 if (fdp == NULL) 2268 return; 2269 2270 /* 2271 * note: fdp->fd_files may be reallocated out from under us while 2272 * we are blocked in a close. Be careful! 2273 */ 2274 for (i = 0; i <= fdp->fd_lastfile; i++) { 2275 if (i > 2) 2276 break; 2277 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { 2278 struct file *fp; 2279 2280 /* 2281 * NULL-out descriptor prior to close to avoid 2282 * a race while close blocks. 2283 */ 2284 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2285 knote_fdclose(fp, fdp, i); 2286 closef(fp, p); 2287 } 2288 } 2289 } 2290 } 2291 2292 /* 2293 * Close any files on exec? 2294 * 2295 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2296 */ 2297 void 2298 fdcloseexec(struct proc *p) 2299 { 2300 struct filedesc *fdp = p->p_fd; 2301 int i; 2302 2303 /* Certain daemons might not have file descriptors. */ 2304 if (fdp == NULL) 2305 return; 2306 2307 /* 2308 * We cannot cache fd_files since operations may block and rip 2309 * them out from under us. 2310 */ 2311 for (i = 0; i <= fdp->fd_lastfile; i++) { 2312 if (fdp->fd_files[i].fp != NULL && 2313 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { 2314 struct file *fp; 2315 2316 /* 2317 * NULL-out descriptor prior to close to avoid 2318 * a race while close blocks. 2319 */ 2320 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2321 knote_fdclose(fp, fdp, i); 2322 closef(fp, p); 2323 } 2324 } 2325 } 2326 } 2327 2328 /* 2329 * It is unsafe for set[ug]id processes to be started with file 2330 * descriptors 0..2 closed, as these descriptors are given implicit 2331 * significance in the Standard C library. fdcheckstd() will create a 2332 * descriptor referencing /dev/null for each of stdin, stdout, and 2333 * stderr that is not already open. 2334 * 2335 * NOT MPSAFE - calls falloc, vn_open, etc 2336 */ 2337 int 2338 fdcheckstd(struct lwp *lp) 2339 { 2340 struct nlookupdata nd; 2341 struct filedesc *fdp; 2342 struct file *fp; 2343 int retval; 2344 int i, error, flags, devnull; 2345 2346 fdp = lp->lwp_proc->p_fd; 2347 if (fdp == NULL) 2348 return (0); 2349 devnull = -1; 2350 error = 0; 2351 for (i = 0; i < 3; i++) { 2352 if (fdp->fd_files[i].fp != NULL) 2353 continue; 2354 if (devnull < 0) { 2355 if ((error = falloc(lp, &fp, &devnull)) != 0) 2356 break; 2357 2358 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 2359 NLC_FOLLOW|NLC_LOCKVP); 2360 flags = FREAD | FWRITE; 2361 if (error == 0) 2362 error = vn_open(&nd, fp, flags, 0); 2363 if (error == 0) 2364 fsetfd(fdp, fp, devnull); 2365 else 2366 fsetfd(fdp, NULL, devnull); 2367 fdrop(fp); 2368 nlookup_done(&nd); 2369 if (error) 2370 break; 2371 KKASSERT(i == devnull); 2372 } else { 2373 error = kern_dup(DUP_FIXED, devnull, i, &retval); 2374 if (error != 0) 2375 break; 2376 } 2377 } 2378 return (error); 2379 } 2380 2381 /* 2382 * Internal form of close. 2383 * Decrement reference count on file structure. 2384 * Note: td and/or p may be NULL when closing a file 2385 * that was being passed in a message. 2386 * 2387 * MPALMOSTSAFE - acquires mplock for VOP operations 2388 */ 2389 int 2390 closef(struct file *fp, struct proc *p) 2391 { 2392 struct vnode *vp; 2393 struct flock lf; 2394 struct filedesc_to_leader *fdtol; 2395 2396 if (fp == NULL) 2397 return (0); 2398 2399 /* 2400 * POSIX record locking dictates that any close releases ALL 2401 * locks owned by this process. This is handled by setting 2402 * a flag in the unlock to free ONLY locks obeying POSIX 2403 * semantics, and not to free BSD-style file locks. 2404 * If the descriptor was in a message, POSIX-style locks 2405 * aren't passed with the descriptor. 2406 */ 2407 if (p != NULL && fp->f_type == DTYPE_VNODE && 2408 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2409 ) { 2410 if ((p->p_leader->p_flags & P_ADVLOCK) != 0) { 2411 lf.l_whence = SEEK_SET; 2412 lf.l_start = 0; 2413 lf.l_len = 0; 2414 lf.l_type = F_UNLCK; 2415 vp = (struct vnode *)fp->f_data; 2416 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 2417 &lf, F_POSIX); 2418 } 2419 fdtol = p->p_fdtol; 2420 if (fdtol != NULL) { 2421 lwkt_gettoken(&p->p_token); 2422 /* 2423 * Handle special case where file descriptor table 2424 * is shared between multiple process leaders. 2425 */ 2426 for (fdtol = fdtol->fdl_next; 2427 fdtol != p->p_fdtol; 2428 fdtol = fdtol->fdl_next) { 2429 if ((fdtol->fdl_leader->p_flags & 2430 P_ADVLOCK) == 0) 2431 continue; 2432 fdtol->fdl_holdcount++; 2433 lf.l_whence = SEEK_SET; 2434 lf.l_start = 0; 2435 lf.l_len = 0; 2436 lf.l_type = F_UNLCK; 2437 vp = (struct vnode *)fp->f_data; 2438 (void) VOP_ADVLOCK(vp, 2439 (caddr_t)fdtol->fdl_leader, 2440 F_UNLCK, &lf, F_POSIX); 2441 fdtol->fdl_holdcount--; 2442 if (fdtol->fdl_holdcount == 0 && 2443 fdtol->fdl_wakeup != 0) { 2444 fdtol->fdl_wakeup = 0; 2445 wakeup(fdtol); 2446 } 2447 } 2448 lwkt_reltoken(&p->p_token); 2449 } 2450 } 2451 return (fdrop(fp)); 2452 } 2453 2454 /* 2455 * MPSAFE 2456 * 2457 * fhold() can only be called if f_count is already at least 1 (i.e. the 2458 * caller of fhold() already has a reference to the file pointer in some 2459 * manner or other). 2460 * 2461 * f_count is not spin-locked. Instead, atomic ops are used for 2462 * incrementing, decrementing, and handling the 1->0 transition. 2463 */ 2464 void 2465 fhold(struct file *fp) 2466 { 2467 atomic_add_int(&fp->f_count, 1); 2468 } 2469 2470 /* 2471 * fdrop() - drop a reference to a descriptor 2472 * 2473 * MPALMOSTSAFE - acquires mplock for final close sequence 2474 */ 2475 int 2476 fdrop(struct file *fp) 2477 { 2478 struct flock lf; 2479 struct vnode *vp; 2480 int error; 2481 2482 /* 2483 * A combined fetch and subtract is needed to properly detect 2484 * 1->0 transitions, otherwise two cpus dropping from a ref 2485 * count of 2 might both try to run the 1->0 code. 2486 */ 2487 if (atomic_fetchadd_int(&fp->f_count, -1) > 1) 2488 return (0); 2489 2490 KKASSERT(SLIST_FIRST(&fp->f_klist) == NULL); 2491 2492 /* 2493 * The last reference has gone away, we own the fp structure free 2494 * and clear. 2495 */ 2496 if (fp->f_count < 0) 2497 panic("fdrop: count < 0"); 2498 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && 2499 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2500 ) { 2501 lf.l_whence = SEEK_SET; 2502 lf.l_start = 0; 2503 lf.l_len = 0; 2504 lf.l_type = F_UNLCK; 2505 vp = (struct vnode *)fp->f_data; 2506 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2507 } 2508 if (fp->f_ops != &badfileops) 2509 error = fo_close(fp); 2510 else 2511 error = 0; 2512 ffree(fp); 2513 return (error); 2514 } 2515 2516 /* 2517 * Apply an advisory lock on a file descriptor. 2518 * 2519 * Just attempt to get a record lock of the requested type on 2520 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2521 * 2522 * MPALMOSTSAFE 2523 */ 2524 int 2525 sys_flock(struct flock_args *uap) 2526 { 2527 struct proc *p = curproc; 2528 struct file *fp; 2529 struct vnode *vp; 2530 struct flock lf; 2531 int error; 2532 2533 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 2534 return (EBADF); 2535 if (fp->f_type != DTYPE_VNODE) { 2536 error = EOPNOTSUPP; 2537 goto done; 2538 } 2539 vp = (struct vnode *)fp->f_data; 2540 lf.l_whence = SEEK_SET; 2541 lf.l_start = 0; 2542 lf.l_len = 0; 2543 if (uap->how & LOCK_UN) { 2544 lf.l_type = F_UNLCK; 2545 fp->f_flag &= ~FHASLOCK; 2546 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2547 goto done; 2548 } 2549 if (uap->how & LOCK_EX) 2550 lf.l_type = F_WRLCK; 2551 else if (uap->how & LOCK_SH) 2552 lf.l_type = F_RDLCK; 2553 else { 2554 error = EBADF; 2555 goto done; 2556 } 2557 fp->f_flag |= FHASLOCK; 2558 if (uap->how & LOCK_NB) 2559 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); 2560 else 2561 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); 2562 done: 2563 fdrop(fp); 2564 return (error); 2565 } 2566 2567 /* 2568 * File Descriptor pseudo-device driver (/dev/fd/). 2569 * 2570 * Opening minor device N dup()s the file (if any) connected to file 2571 * descriptor N belonging to the calling process. Note that this driver 2572 * consists of only the ``open()'' routine, because all subsequent 2573 * references to this file will be direct to the other driver. 2574 */ 2575 static int 2576 fdopen(struct dev_open_args *ap) 2577 { 2578 thread_t td = curthread; 2579 2580 KKASSERT(td->td_lwp != NULL); 2581 2582 /* 2583 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the 2584 * the file descriptor being sought for duplication. The error 2585 * return ensures that the vnode for this device will be released 2586 * by vn_open. Open will detect this special error and take the 2587 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2588 * will simply report the error. 2589 */ 2590 td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev); 2591 return (ENODEV); 2592 } 2593 2594 /* 2595 * The caller has reserved the file descriptor dfd for us. On success we 2596 * must fsetfd() it. On failure the caller will clean it up. 2597 * 2598 * MPSAFE 2599 */ 2600 int 2601 dupfdopen(struct filedesc *fdp, int dfd, int sfd, int mode, int error) 2602 { 2603 struct file *wfp; 2604 struct file *xfp; 2605 int werror; 2606 2607 if ((wfp = holdfp(fdp, sfd, -1)) == NULL) 2608 return (EBADF); 2609 2610 /* 2611 * Close a revoke/dup race. Duping a descriptor marked as revoked 2612 * will dup a dummy descriptor instead of the real one. 2613 */ 2614 if (wfp->f_flag & FREVOKED) { 2615 kprintf("Warning: attempt to dup() a revoked descriptor\n"); 2616 fdrop(wfp); 2617 wfp = NULL; 2618 werror = falloc(NULL, &wfp, NULL); 2619 if (werror) 2620 return (werror); 2621 } 2622 2623 /* 2624 * There are two cases of interest here. 2625 * 2626 * For ENODEV simply dup sfd to file descriptor dfd and return. 2627 * 2628 * For ENXIO steal away the file structure from sfd and store it 2629 * dfd. sfd is effectively closed by this operation. 2630 * 2631 * Any other error code is just returned. 2632 */ 2633 switch (error) { 2634 case ENODEV: 2635 /* 2636 * Check that the mode the file is being opened for is a 2637 * subset of the mode of the existing descriptor. 2638 */ 2639 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2640 error = EACCES; 2641 break; 2642 } 2643 spin_lock(&fdp->fd_spin); 2644 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2645 fsetfd_locked(fdp, wfp, dfd); 2646 spin_unlock(&fdp->fd_spin); 2647 error = 0; 2648 break; 2649 case ENXIO: 2650 /* 2651 * Steal away the file pointer from dfd, and stuff it into indx. 2652 */ 2653 spin_lock(&fdp->fd_spin); 2654 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2655 fsetfd(fdp, wfp, dfd); 2656 if ((xfp = funsetfd_locked(fdp, sfd)) != NULL) { 2657 spin_unlock(&fdp->fd_spin); 2658 fdrop(xfp); 2659 } else { 2660 spin_unlock(&fdp->fd_spin); 2661 } 2662 error = 0; 2663 break; 2664 default: 2665 break; 2666 } 2667 fdrop(wfp); 2668 return (error); 2669 } 2670 2671 /* 2672 * NOT MPSAFE - I think these refer to a common file descriptor table 2673 * and we need to spinlock that to link fdtol in. 2674 */ 2675 struct filedesc_to_leader * 2676 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2677 struct proc *leader) 2678 { 2679 struct filedesc_to_leader *fdtol; 2680 2681 fdtol = kmalloc(sizeof(struct filedesc_to_leader), 2682 M_FILEDESC_TO_LEADER, M_WAITOK | M_ZERO); 2683 fdtol->fdl_refcount = 1; 2684 fdtol->fdl_holdcount = 0; 2685 fdtol->fdl_wakeup = 0; 2686 fdtol->fdl_leader = leader; 2687 if (old != NULL) { 2688 fdtol->fdl_next = old->fdl_next; 2689 fdtol->fdl_prev = old; 2690 old->fdl_next = fdtol; 2691 fdtol->fdl_next->fdl_prev = fdtol; 2692 } else { 2693 fdtol->fdl_next = fdtol; 2694 fdtol->fdl_prev = fdtol; 2695 } 2696 return fdtol; 2697 } 2698 2699 /* 2700 * Scan all file pointers in the system. The callback is made with 2701 * the master list spinlock held exclusively. 2702 * 2703 * MPSAFE 2704 */ 2705 void 2706 allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) 2707 { 2708 struct file *fp; 2709 int res; 2710 2711 spin_lock(&filehead_spin); 2712 LIST_FOREACH(fp, &filehead, f_list) { 2713 res = callback(fp, data); 2714 if (res < 0) 2715 break; 2716 } 2717 spin_unlock(&filehead_spin); 2718 } 2719 2720 /* 2721 * Get file structures. 2722 * 2723 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) 2724 */ 2725 2726 struct sysctl_kern_file_info { 2727 int count; 2728 int error; 2729 struct sysctl_req *req; 2730 }; 2731 2732 static int sysctl_kern_file_callback(struct proc *p, void *data); 2733 2734 static int 2735 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2736 { 2737 struct sysctl_kern_file_info info; 2738 2739 /* 2740 * Note: because the number of file descriptors is calculated 2741 * in different ways for sizing vs returning the data, 2742 * there is information leakage from the first loop. However, 2743 * it is of a similar order of magnitude to the leakage from 2744 * global system statistics such as kern.openfiles. 2745 * 2746 * When just doing a count, note that we cannot just count 2747 * the elements and add f_count via the filehead list because 2748 * threaded processes share their descriptor table and f_count might 2749 * still be '1' in that case. 2750 * 2751 * Since the SYSCTL op can block, we must hold the process to 2752 * prevent it being ripped out from under us either in the 2753 * file descriptor loop or in the greater LIST_FOREACH. The 2754 * process may be in varying states of disrepair. If the process 2755 * is in SZOMB we may have caught it just as it is being removed 2756 * from the allproc list, we must skip it in that case to maintain 2757 * an unbroken chain through the allproc list. 2758 */ 2759 info.count = 0; 2760 info.error = 0; 2761 info.req = req; 2762 allproc_scan(sysctl_kern_file_callback, &info); 2763 2764 /* 2765 * When just calculating the size, overestimate a bit to try to 2766 * prevent system activity from causing the buffer-fill call 2767 * to fail later on. 2768 */ 2769 if (req->oldptr == NULL) { 2770 info.count = (info.count + 16) + (info.count / 10); 2771 info.error = SYSCTL_OUT(req, NULL, 2772 info.count * sizeof(struct kinfo_file)); 2773 } 2774 return (info.error); 2775 } 2776 2777 static int 2778 sysctl_kern_file_callback(struct proc *p, void *data) 2779 { 2780 struct sysctl_kern_file_info *info = data; 2781 struct kinfo_file kf; 2782 struct filedesc *fdp; 2783 struct file *fp; 2784 uid_t uid; 2785 int n; 2786 2787 if (p->p_stat == SIDL || p->p_stat == SZOMB) 2788 return(0); 2789 if (!PRISON_CHECK(info->req->td->td_ucred, p->p_ucred) != 0) 2790 return(0); 2791 2792 /* 2793 * Softref the fdp to prevent it from being destroyed 2794 */ 2795 spin_lock(&p->p_spin); 2796 if ((fdp = p->p_fd) == NULL) { 2797 spin_unlock(&p->p_spin); 2798 return(0); 2799 } 2800 atomic_add_int(&fdp->fd_softrefs, 1); 2801 spin_unlock(&p->p_spin); 2802 2803 /* 2804 * The fdp's own spinlock prevents the contents from being 2805 * modified. 2806 */ 2807 spin_lock_shared(&fdp->fd_spin); 2808 for (n = 0; n < fdp->fd_nfiles; ++n) { 2809 if ((fp = fdp->fd_files[n].fp) == NULL) 2810 continue; 2811 if (info->req->oldptr == NULL) { 2812 ++info->count; 2813 } else { 2814 uid = p->p_ucred ? p->p_ucred->cr_uid : -1; 2815 kcore_make_file(&kf, fp, p->p_pid, uid, n); 2816 spin_unlock_shared(&fdp->fd_spin); 2817 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); 2818 spin_lock_shared(&fdp->fd_spin); 2819 if (info->error) 2820 break; 2821 } 2822 } 2823 spin_unlock_shared(&fdp->fd_spin); 2824 atomic_subtract_int(&fdp->fd_softrefs, 1); 2825 if (info->error) 2826 return(-1); 2827 return(0); 2828 } 2829 2830 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2831 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 2832 2833 SYSCTL_INT(_kern, OID_AUTO, minfilesperproc, CTLFLAG_RW, 2834 &minfilesperproc, 0, "Minimum files allowed open per process"); 2835 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2836 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2837 SYSCTL_INT(_kern, OID_AUTO, maxfilesperuser, CTLFLAG_RW, 2838 &maxfilesperuser, 0, "Maximum files allowed open per user"); 2839 2840 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2841 &maxfiles, 0, "Maximum number of files"); 2842 2843 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 2844 &maxfilesrootres, 0, "Descriptors reserved for root use"); 2845 2846 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2847 &nfiles, 0, "System-wide number of open files"); 2848 2849 static void 2850 fildesc_drvinit(void *unused) 2851 { 2852 int fd; 2853 2854 for (fd = 0; fd < NUMFDESC; fd++) { 2855 make_dev(&fildesc_ops, fd, 2856 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 2857 } 2858 2859 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 2860 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 2861 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 2862 } 2863 2864 /* 2865 * MPSAFE 2866 */ 2867 struct fileops badfileops = { 2868 .fo_read = badfo_readwrite, 2869 .fo_write = badfo_readwrite, 2870 .fo_ioctl = badfo_ioctl, 2871 .fo_kqfilter = badfo_kqfilter, 2872 .fo_stat = badfo_stat, 2873 .fo_close = badfo_close, 2874 .fo_shutdown = badfo_shutdown 2875 }; 2876 2877 int 2878 badfo_readwrite( 2879 struct file *fp, 2880 struct uio *uio, 2881 struct ucred *cred, 2882 int flags 2883 ) { 2884 return (EBADF); 2885 } 2886 2887 int 2888 badfo_ioctl(struct file *fp, u_long com, caddr_t data, 2889 struct ucred *cred, struct sysmsg *msgv) 2890 { 2891 return (EBADF); 2892 } 2893 2894 /* 2895 * Must return an error to prevent registration, typically 2896 * due to a revoked descriptor (file_filtops assigned). 2897 */ 2898 int 2899 badfo_kqfilter(struct file *fp, struct knote *kn) 2900 { 2901 return (EOPNOTSUPP); 2902 } 2903 2904 /* 2905 * MPSAFE 2906 */ 2907 int 2908 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) 2909 { 2910 return (EBADF); 2911 } 2912 2913 /* 2914 * MPSAFE 2915 */ 2916 int 2917 badfo_close(struct file *fp) 2918 { 2919 return (EBADF); 2920 } 2921 2922 /* 2923 * MPSAFE 2924 */ 2925 int 2926 badfo_shutdown(struct file *fp, int how) 2927 { 2928 return (EBADF); 2929 } 2930 2931 /* 2932 * MPSAFE 2933 */ 2934 int 2935 nofo_shutdown(struct file *fp, int how) 2936 { 2937 return (EOPNOTSUPP); 2938 } 2939 2940 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2941 fildesc_drvinit,NULL) 2942