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, "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 | DUP_FCNTL, fd, newmin, 255 &dat->fc_fd); 256 return (error); 257 case F_DUPFD_CLOEXEC: 258 newmin = dat->fc_fd; 259 error = kern_dup(DUP_VARIABLE | DUP_CLOEXEC | DUP_FCNTL, 260 fd, newmin, &dat->fc_fd); 261 return (error); 262 case F_DUP2FD: 263 newmin = dat->fc_fd; 264 error = kern_dup(DUP_FIXED, fd, newmin, &dat->fc_fd); 265 return (error); 266 case F_DUP2FD_CLOEXEC: 267 newmin = dat->fc_fd; 268 error = kern_dup(DUP_FIXED | DUP_CLOEXEC, fd, newmin, 269 &dat->fc_fd); 270 return (error); 271 default: 272 break; 273 } 274 275 /* 276 * Operations on file pointers 277 */ 278 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 279 return (EBADF); 280 281 switch (cmd) { 282 case F_GETFL: 283 dat->fc_flags = OFLAGS(fp->f_flag); 284 error = 0; 285 break; 286 287 case F_SETFL: 288 oflags = fp->f_flag; 289 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 290 nflags |= oflags & ~FCNTLFLAGS; 291 292 error = 0; 293 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) 294 error = EINVAL; 295 if (error == 0 && ((nflags ^ oflags) & FASYNC)) { 296 tmp = nflags & FASYNC; 297 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, 298 cred, NULL); 299 } 300 if (error == 0) 301 fp->f_flag = nflags; 302 break; 303 304 case F_GETOWN: 305 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, 306 cred, NULL); 307 break; 308 309 case F_SETOWN: 310 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, 311 cred, NULL); 312 break; 313 314 case F_SETLKW: 315 flg |= F_WAIT; 316 /* Fall into F_SETLK */ 317 318 case F_SETLK: 319 if (fp->f_type != DTYPE_VNODE) { 320 error = EBADF; 321 break; 322 } 323 vp = (struct vnode *)fp->f_data; 324 325 /* 326 * copyin/lockop may block 327 */ 328 if (dat->fc_flock.l_whence == SEEK_CUR) 329 dat->fc_flock.l_start += fp->f_offset; 330 331 switch (dat->fc_flock.l_type) { 332 case F_RDLCK: 333 if ((fp->f_flag & FREAD) == 0) { 334 error = EBADF; 335 break; 336 } 337 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 338 lwkt_gettoken(&p->p_leader->p_token); 339 p->p_leader->p_flags |= P_ADVLOCK; 340 lwkt_reltoken(&p->p_leader->p_token); 341 } 342 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 343 &dat->fc_flock, flg); 344 break; 345 case F_WRLCK: 346 if ((fp->f_flag & FWRITE) == 0) { 347 error = EBADF; 348 break; 349 } 350 if ((p->p_leader->p_flags & P_ADVLOCK) == 0) { 351 lwkt_gettoken(&p->p_leader->p_token); 352 p->p_leader->p_flags |= P_ADVLOCK; 353 lwkt_reltoken(&p->p_leader->p_token); 354 } 355 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 356 &dat->fc_flock, flg); 357 break; 358 case F_UNLCK: 359 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 360 &dat->fc_flock, F_POSIX); 361 break; 362 default: 363 error = EINVAL; 364 break; 365 } 366 367 /* 368 * It is possible to race a close() on the descriptor while 369 * we were blocked getting the lock. If this occurs the 370 * close might not have caught the lock. 371 */ 372 if (checkfdclosed(p->p_fd, fd, fp)) { 373 dat->fc_flock.l_whence = SEEK_SET; 374 dat->fc_flock.l_start = 0; 375 dat->fc_flock.l_len = 0; 376 dat->fc_flock.l_type = F_UNLCK; 377 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 378 F_UNLCK, &dat->fc_flock, F_POSIX); 379 } 380 break; 381 382 case F_GETLK: 383 if (fp->f_type != DTYPE_VNODE) { 384 error = EBADF; 385 break; 386 } 387 vp = (struct vnode *)fp->f_data; 388 /* 389 * copyin/lockop may block 390 */ 391 if (dat->fc_flock.l_type != F_RDLCK && 392 dat->fc_flock.l_type != F_WRLCK && 393 dat->fc_flock.l_type != F_UNLCK) { 394 error = EINVAL; 395 break; 396 } 397 if (dat->fc_flock.l_whence == SEEK_CUR) 398 dat->fc_flock.l_start += fp->f_offset; 399 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 400 &dat->fc_flock, F_POSIX); 401 break; 402 default: 403 error = EINVAL; 404 break; 405 } 406 407 fdrop(fp); 408 return (error); 409 } 410 411 /* 412 * The file control system call. 413 * 414 * MPSAFE 415 */ 416 int 417 sys_fcntl(struct fcntl_args *uap) 418 { 419 union fcntl_dat dat; 420 int error; 421 422 switch (uap->cmd) { 423 case F_DUPFD: 424 case F_DUP2FD: 425 case F_DUPFD_CLOEXEC: 426 case F_DUP2FD_CLOEXEC: 427 dat.fc_fd = uap->arg; 428 break; 429 case F_SETFD: 430 dat.fc_cloexec = uap->arg; 431 break; 432 case F_SETFL: 433 dat.fc_flags = uap->arg; 434 break; 435 case F_SETOWN: 436 dat.fc_owner = uap->arg; 437 break; 438 case F_SETLKW: 439 case F_SETLK: 440 case F_GETLK: 441 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 442 sizeof(struct flock)); 443 if (error) 444 return (error); 445 break; 446 } 447 448 error = kern_fcntl(uap->fd, uap->cmd, &dat, curthread->td_ucred); 449 450 if (error == 0) { 451 switch (uap->cmd) { 452 case F_DUPFD: 453 case F_DUP2FD: 454 case F_DUPFD_CLOEXEC: 455 case F_DUP2FD_CLOEXEC: 456 uap->sysmsg_result = dat.fc_fd; 457 break; 458 case F_GETFD: 459 uap->sysmsg_result = dat.fc_cloexec; 460 break; 461 case F_GETFL: 462 uap->sysmsg_result = dat.fc_flags; 463 break; 464 case F_GETOWN: 465 uap->sysmsg_result = dat.fc_owner; 466 break; 467 case F_GETLK: 468 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 469 sizeof(struct flock)); 470 break; 471 } 472 } 473 474 return (error); 475 } 476 477 /* 478 * Common code for dup, dup2, and fcntl(F_DUPFD). 479 * 480 * There are four type flags: DUP_FCNTL, DUP_FIXED, DUP_VARIABLE, and 481 * DUP_CLOEXEC. 482 * 483 * DUP_FCNTL is for handling EINVAL vs. EBADF differences between 484 * fcntl()'s F_DUPFD and F_DUPFD_CLOEXEC and dup2() (per POSIX). 485 * The next two flags are mutually exclusive, and the fourth is optional. 486 * DUP_FIXED tells kern_dup() to destructively dup over an existing file 487 * descriptor if "new" is already open. DUP_VARIABLE tells kern_dup() 488 * to find the lowest unused file descriptor that is greater than or 489 * equal to "new". DUP_CLOEXEC, which works with either of the first 490 * two flags, sets the close-on-exec flag on the "new" file descriptor. 491 * 492 * MPSAFE 493 */ 494 int 495 kern_dup(int flags, int old, int new, int *res) 496 { 497 struct thread *td = curthread; 498 struct proc *p = td->td_proc; 499 struct filedesc *fdp = p->p_fd; 500 struct file *fp; 501 struct file *delfp; 502 int oldflags; 503 int holdleaders; 504 int dtsize; 505 int error, newfd; 506 507 /* 508 * Verify that we have a valid descriptor to dup from and 509 * possibly to dup to. When the new descriptor is out of 510 * bounds, fcntl()'s F_DUPFD and F_DUPFD_CLOEXEC must 511 * return EINVAL, while dup2() returns EBADF in 512 * this case. 513 * 514 * NOTE: maxfilesperuser is not applicable to dup() 515 */ 516 retry: 517 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 518 dtsize = INT_MAX; 519 else 520 dtsize = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 521 if (dtsize > maxfilesperproc) 522 dtsize = maxfilesperproc; 523 if (dtsize < minfilesperproc) 524 dtsize = minfilesperproc; 525 526 if (new < 0 || new > dtsize) 527 return (flags & DUP_FCNTL ? EINVAL : EBADF); 528 529 spin_lock(&fdp->fd_spin); 530 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { 531 spin_unlock(&fdp->fd_spin); 532 return (EBADF); 533 } 534 if ((flags & DUP_FIXED) && old == new) { 535 *res = new; 536 if (flags & DUP_CLOEXEC) 537 fdp->fd_files[new].fileflags |= UF_EXCLOSE; 538 spin_unlock(&fdp->fd_spin); 539 return (0); 540 } 541 fp = fdp->fd_files[old].fp; 542 oldflags = fdp->fd_files[old].fileflags; 543 fhold(fp); /* MPSAFE - can be called with a spinlock held */ 544 545 /* 546 * Allocate a new descriptor if DUP_VARIABLE, or expand the table 547 * if the requested descriptor is beyond the current table size. 548 * 549 * This can block. Retry if the source descriptor no longer matches 550 * or if our expectation in the expansion case races. 551 * 552 * If we are not expanding or allocating a new decriptor, then reset 553 * the target descriptor to a reserved state so we have a uniform 554 * setup for the next code block. 555 */ 556 if ((flags & DUP_VARIABLE) || new >= fdp->fd_nfiles) { 557 spin_unlock(&fdp->fd_spin); 558 error = fdalloc(p, new, &newfd); 559 spin_lock(&fdp->fd_spin); 560 if (error) { 561 spin_unlock(&fdp->fd_spin); 562 fdrop(fp); 563 return (error); 564 } 565 /* 566 * Check for ripout 567 */ 568 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { 569 fsetfd_locked(fdp, NULL, newfd); 570 spin_unlock(&fdp->fd_spin); 571 fdrop(fp); 572 goto retry; 573 } 574 /* 575 * Check for expansion race 576 */ 577 if ((flags & DUP_VARIABLE) == 0 && new != newfd) { 578 fsetfd_locked(fdp, NULL, newfd); 579 spin_unlock(&fdp->fd_spin); 580 fdrop(fp); 581 goto retry; 582 } 583 /* 584 * Check for ripout, newfd reused old (this case probably 585 * can't occur). 586 */ 587 if (old == newfd) { 588 fsetfd_locked(fdp, NULL, newfd); 589 spin_unlock(&fdp->fd_spin); 590 fdrop(fp); 591 goto retry; 592 } 593 new = newfd; 594 delfp = NULL; 595 } else { 596 if (fdp->fd_files[new].reserved) { 597 spin_unlock(&fdp->fd_spin); 598 fdrop(fp); 599 kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new); 600 tsleep(fdp, 0, "fdres", hz); 601 goto retry; 602 } 603 604 /* 605 * If the target descriptor was never allocated we have 606 * to allocate it. If it was we have to clean out the 607 * old descriptor. delfp inherits the ref from the 608 * descriptor table. 609 */ 610 delfp = fdp->fd_files[new].fp; 611 fdp->fd_files[new].fp = NULL; 612 fdp->fd_files[new].reserved = 1; 613 if (delfp == NULL) { 614 fdreserve_locked(fdp, new, 1); 615 if (new > fdp->fd_lastfile) 616 fdp->fd_lastfile = new; 617 } 618 619 } 620 621 /* 622 * NOTE: still holding an exclusive spinlock 623 */ 624 625 /* 626 * If a descriptor is being overwritten we may hve to tell 627 * fdfree() to sleep to ensure that all relevant process 628 * leaders can be traversed in closef(). 629 */ 630 if (delfp != NULL && p->p_fdtol != NULL) { 631 fdp->fd_holdleaderscount++; 632 holdleaders = 1; 633 } else { 634 holdleaders = 0; 635 } 636 KASSERT(delfp == NULL || (flags & DUP_FIXED), 637 ("dup() picked an open file")); 638 639 /* 640 * Duplicate the source descriptor, update lastfile. If the new 641 * descriptor was not allocated and we aren't replacing an existing 642 * descriptor we have to mark the descriptor as being in use. 643 * 644 * The fd_files[] array inherits fp's hold reference. 645 */ 646 fsetfd_locked(fdp, fp, new); 647 if ((flags & DUP_CLOEXEC) != 0) 648 fdp->fd_files[new].fileflags = oldflags | UF_EXCLOSE; 649 else 650 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; 651 spin_unlock(&fdp->fd_spin); 652 fdrop(fp); 653 *res = new; 654 655 /* 656 * If we dup'd over a valid file, we now own the reference to it 657 * and must dispose of it using closef() semantics (as if a 658 * close() were performed on it). 659 */ 660 if (delfp) { 661 if (SLIST_FIRST(&delfp->f_klist)) 662 knote_fdclose(delfp, fdp, new); 663 closef(delfp, p); 664 if (holdleaders) { 665 spin_lock(&fdp->fd_spin); 666 fdp->fd_holdleaderscount--; 667 if (fdp->fd_holdleaderscount == 0 && 668 fdp->fd_holdleaderswakeup != 0) { 669 fdp->fd_holdleaderswakeup = 0; 670 spin_unlock(&fdp->fd_spin); 671 wakeup(&fdp->fd_holdleaderscount); 672 } else { 673 spin_unlock(&fdp->fd_spin); 674 } 675 } 676 } 677 return (0); 678 } 679 680 /* 681 * If sigio is on the list associated with a process or process group, 682 * disable signalling from the device, remove sigio from the list and 683 * free sigio. 684 * 685 * MPSAFE 686 */ 687 void 688 funsetown(struct sigio **sigiop) 689 { 690 struct pgrp *pgrp; 691 struct proc *p; 692 struct sigio *sigio; 693 694 if ((sigio = *sigiop) != NULL) { 695 lwkt_gettoken(&sigio_token); /* protect sigio */ 696 KKASSERT(sigiop == sigio->sio_myref); 697 sigio = *sigiop; 698 *sigiop = NULL; 699 lwkt_reltoken(&sigio_token); 700 } 701 if (sigio == NULL) 702 return; 703 704 if (sigio->sio_pgid < 0) { 705 pgrp = sigio->sio_pgrp; 706 sigio->sio_pgrp = NULL; 707 lwkt_gettoken(&pgrp->pg_token); 708 SLIST_REMOVE(&pgrp->pg_sigiolst, sigio, sigio, sio_pgsigio); 709 lwkt_reltoken(&pgrp->pg_token); 710 pgrel(pgrp); 711 } else /* if ((*sigiop)->sio_pgid > 0) */ { 712 p = sigio->sio_proc; 713 sigio->sio_proc = NULL; 714 PHOLD(p); 715 lwkt_gettoken(&p->p_token); 716 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, sio_pgsigio); 717 lwkt_reltoken(&p->p_token); 718 PRELE(p); 719 } 720 crfree(sigio->sio_ucred); 721 sigio->sio_ucred = NULL; 722 kfree(sigio, M_SIGIO); 723 } 724 725 /* 726 * Free a list of sigio structures. Caller is responsible for ensuring 727 * that the list is MPSAFE. 728 * 729 * MPSAFE 730 */ 731 void 732 funsetownlst(struct sigiolst *sigiolst) 733 { 734 struct sigio *sigio; 735 736 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 737 funsetown(sigio->sio_myref); 738 } 739 740 /* 741 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 742 * 743 * After permission checking, add a sigio structure to the sigio list for 744 * the process or process group. 745 * 746 * MPSAFE 747 */ 748 int 749 fsetown(pid_t pgid, struct sigio **sigiop) 750 { 751 struct proc *proc = NULL; 752 struct pgrp *pgrp = NULL; 753 struct sigio *sigio; 754 int error; 755 756 if (pgid == 0) { 757 funsetown(sigiop); 758 return (0); 759 } 760 761 if (pgid > 0) { 762 proc = pfind(pgid); 763 if (proc == NULL) { 764 error = ESRCH; 765 goto done; 766 } 767 768 /* 769 * Policy - Don't allow a process to FSETOWN a process 770 * in another session. 771 * 772 * Remove this test to allow maximum flexibility or 773 * restrict FSETOWN to the current process or process 774 * group for maximum safety. 775 */ 776 if (proc->p_session != curproc->p_session) { 777 error = EPERM; 778 goto done; 779 } 780 } else /* if (pgid < 0) */ { 781 pgrp = pgfind(-pgid); 782 if (pgrp == NULL) { 783 error = ESRCH; 784 goto done; 785 } 786 787 /* 788 * Policy - Don't allow a process to FSETOWN a process 789 * in another session. 790 * 791 * Remove this test to allow maximum flexibility or 792 * restrict FSETOWN to the current process or process 793 * group for maximum safety. 794 */ 795 if (pgrp->pg_session != curproc->p_session) { 796 error = EPERM; 797 goto done; 798 } 799 } 800 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK | M_ZERO); 801 if (pgid > 0) { 802 KKASSERT(pgrp == NULL); 803 lwkt_gettoken(&proc->p_token); 804 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 805 sigio->sio_proc = proc; 806 lwkt_reltoken(&proc->p_token); 807 } else { 808 KKASSERT(proc == NULL); 809 lwkt_gettoken(&pgrp->pg_token); 810 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 811 sigio->sio_pgrp = pgrp; 812 lwkt_reltoken(&pgrp->pg_token); 813 pgrp = NULL; 814 } 815 sigio->sio_pgid = pgid; 816 sigio->sio_ucred = crhold(curthread->td_ucred); 817 /* It would be convenient if p_ruid was in ucred. */ 818 sigio->sio_ruid = sigio->sio_ucred->cr_ruid; 819 sigio->sio_myref = sigiop; 820 821 lwkt_gettoken(&sigio_token); 822 while (*sigiop) 823 funsetown(sigiop); 824 *sigiop = sigio; 825 lwkt_reltoken(&sigio_token); 826 error = 0; 827 done: 828 if (pgrp) 829 pgrel(pgrp); 830 if (proc) 831 PRELE(proc); 832 return (error); 833 } 834 835 /* 836 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 837 * 838 * MPSAFE 839 */ 840 pid_t 841 fgetown(struct sigio **sigiop) 842 { 843 struct sigio *sigio; 844 pid_t own; 845 846 lwkt_gettoken_shared(&sigio_token); 847 sigio = *sigiop; 848 own = (sigio != NULL ? sigio->sio_pgid : 0); 849 lwkt_reltoken(&sigio_token); 850 851 return (own); 852 } 853 854 /* 855 * Close many file descriptors. 856 * 857 * MPSAFE 858 */ 859 int 860 sys_closefrom(struct closefrom_args *uap) 861 { 862 return(kern_closefrom(uap->fd)); 863 } 864 865 /* 866 * Close all file descriptors greater then or equal to fd 867 * 868 * MPSAFE 869 */ 870 int 871 kern_closefrom(int fd) 872 { 873 struct thread *td = curthread; 874 struct proc *p = td->td_proc; 875 struct filedesc *fdp; 876 877 KKASSERT(p); 878 fdp = p->p_fd; 879 880 if (fd < 0) 881 return (EINVAL); 882 883 /* 884 * NOTE: This function will skip unassociated descriptors and 885 * reserved descriptors that have not yet been assigned. 886 * fd_lastfile can change as a side effect of kern_close(). 887 */ 888 spin_lock(&fdp->fd_spin); 889 while (fd <= fdp->fd_lastfile) { 890 if (fdp->fd_files[fd].fp != NULL) { 891 spin_unlock(&fdp->fd_spin); 892 /* ok if this races another close */ 893 if (kern_close(fd) == EINTR) 894 return (EINTR); 895 spin_lock(&fdp->fd_spin); 896 } 897 ++fd; 898 } 899 spin_unlock(&fdp->fd_spin); 900 return (0); 901 } 902 903 /* 904 * Close a file descriptor. 905 * 906 * MPSAFE 907 */ 908 int 909 sys_close(struct close_args *uap) 910 { 911 return(kern_close(uap->fd)); 912 } 913 914 /* 915 * MPSAFE 916 */ 917 int 918 kern_close(int fd) 919 { 920 struct thread *td = curthread; 921 struct proc *p = td->td_proc; 922 struct filedesc *fdp; 923 struct file *fp; 924 int error; 925 int holdleaders; 926 927 KKASSERT(p); 928 fdp = p->p_fd; 929 930 spin_lock(&fdp->fd_spin); 931 if ((fp = funsetfd_locked(fdp, fd)) == NULL) { 932 spin_unlock(&fdp->fd_spin); 933 return (EBADF); 934 } 935 holdleaders = 0; 936 if (p->p_fdtol != NULL) { 937 /* 938 * Ask fdfree() to sleep to ensure that all relevant 939 * process leaders can be traversed in closef(). 940 */ 941 fdp->fd_holdleaderscount++; 942 holdleaders = 1; 943 } 944 945 /* 946 * we now hold the fp reference that used to be owned by the descriptor 947 * array. 948 */ 949 spin_unlock(&fdp->fd_spin); 950 if (SLIST_FIRST(&fp->f_klist)) 951 knote_fdclose(fp, fdp, fd); 952 error = closef(fp, p); 953 if (holdleaders) { 954 spin_lock(&fdp->fd_spin); 955 fdp->fd_holdleaderscount--; 956 if (fdp->fd_holdleaderscount == 0 && 957 fdp->fd_holdleaderswakeup != 0) { 958 fdp->fd_holdleaderswakeup = 0; 959 spin_unlock(&fdp->fd_spin); 960 wakeup(&fdp->fd_holdleaderscount); 961 } else { 962 spin_unlock(&fdp->fd_spin); 963 } 964 } 965 return (error); 966 } 967 968 /* 969 * shutdown_args(int fd, int how) 970 */ 971 int 972 kern_shutdown(int fd, int how) 973 { 974 struct thread *td = curthread; 975 struct proc *p = td->td_proc; 976 struct file *fp; 977 int error; 978 979 KKASSERT(p); 980 981 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 982 return (EBADF); 983 error = fo_shutdown(fp, how); 984 fdrop(fp); 985 986 return (error); 987 } 988 989 /* 990 * MPALMOSTSAFE 991 */ 992 int 993 sys_shutdown(struct shutdown_args *uap) 994 { 995 int error; 996 997 error = kern_shutdown(uap->s, uap->how); 998 999 return (error); 1000 } 1001 1002 /* 1003 * MPSAFE 1004 */ 1005 int 1006 kern_fstat(int fd, struct stat *ub) 1007 { 1008 struct thread *td = curthread; 1009 struct proc *p = td->td_proc; 1010 struct file *fp; 1011 int error; 1012 1013 KKASSERT(p); 1014 1015 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) 1016 return (EBADF); 1017 error = fo_stat(fp, ub, td->td_ucred); 1018 fdrop(fp); 1019 1020 return (error); 1021 } 1022 1023 /* 1024 * Return status information about a file descriptor. 1025 * 1026 * MPSAFE 1027 */ 1028 int 1029 sys_fstat(struct fstat_args *uap) 1030 { 1031 struct stat st; 1032 int error; 1033 1034 error = kern_fstat(uap->fd, &st); 1035 1036 if (error == 0) 1037 error = copyout(&st, uap->sb, sizeof(st)); 1038 return (error); 1039 } 1040 1041 /* 1042 * Return pathconf information about a file descriptor. 1043 * 1044 * MPALMOSTSAFE 1045 */ 1046 int 1047 sys_fpathconf(struct fpathconf_args *uap) 1048 { 1049 struct thread *td = curthread; 1050 struct proc *p = td->td_proc; 1051 struct file *fp; 1052 struct vnode *vp; 1053 int error = 0; 1054 1055 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 1056 return (EBADF); 1057 1058 switch (fp->f_type) { 1059 case DTYPE_PIPE: 1060 case DTYPE_SOCKET: 1061 if (uap->name != _PC_PIPE_BUF) { 1062 error = EINVAL; 1063 } else { 1064 uap->sysmsg_result = PIPE_BUF; 1065 error = 0; 1066 } 1067 break; 1068 case DTYPE_FIFO: 1069 case DTYPE_VNODE: 1070 vp = (struct vnode *)fp->f_data; 1071 error = VOP_PATHCONF(vp, uap->name, &uap->sysmsg_reg); 1072 break; 1073 default: 1074 error = EOPNOTSUPP; 1075 break; 1076 } 1077 fdrop(fp); 1078 return(error); 1079 } 1080 1081 static int fdexpand; 1082 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, 1083 "Number of times a file table has been expanded"); 1084 1085 /* 1086 * Grow the file table so it can hold through descriptor (want). 1087 * 1088 * The fdp's spinlock must be held exclusively on entry and may be held 1089 * exclusively on return. The spinlock may be cycled by the routine. 1090 * 1091 * MPSAFE 1092 */ 1093 static void 1094 fdgrow_locked(struct filedesc *fdp, int want) 1095 { 1096 struct fdnode *newfiles; 1097 struct fdnode *oldfiles; 1098 int nf, extra; 1099 1100 nf = fdp->fd_nfiles; 1101 do { 1102 /* nf has to be of the form 2^n - 1 */ 1103 nf = 2 * nf + 1; 1104 } while (nf <= want); 1105 1106 spin_unlock(&fdp->fd_spin); 1107 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); 1108 spin_lock(&fdp->fd_spin); 1109 1110 /* 1111 * We could have raced another extend while we were not holding 1112 * the spinlock. 1113 */ 1114 if (fdp->fd_nfiles >= nf) { 1115 spin_unlock(&fdp->fd_spin); 1116 kfree(newfiles, M_FILEDESC); 1117 spin_lock(&fdp->fd_spin); 1118 return; 1119 } 1120 /* 1121 * Copy the existing ofile and ofileflags arrays 1122 * and zero the new portion of each array. 1123 */ 1124 extra = nf - fdp->fd_nfiles; 1125 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); 1126 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); 1127 1128 oldfiles = fdp->fd_files; 1129 fdp->fd_files = newfiles; 1130 fdp->fd_nfiles = nf; 1131 1132 if (oldfiles != fdp->fd_builtin_files) { 1133 spin_unlock(&fdp->fd_spin); 1134 kfree(oldfiles, M_FILEDESC); 1135 spin_lock(&fdp->fd_spin); 1136 } 1137 fdexpand++; 1138 } 1139 1140 /* 1141 * Number of nodes in right subtree, including the root. 1142 */ 1143 static __inline int 1144 right_subtree_size(int n) 1145 { 1146 return (n ^ (n | (n + 1))); 1147 } 1148 1149 /* 1150 * Bigger ancestor. 1151 */ 1152 static __inline int 1153 right_ancestor(int n) 1154 { 1155 return (n | (n + 1)); 1156 } 1157 1158 /* 1159 * Smaller ancestor. 1160 */ 1161 static __inline int 1162 left_ancestor(int n) 1163 { 1164 return ((n & (n + 1)) - 1); 1165 } 1166 1167 /* 1168 * Traverse the in-place binary tree buttom-up adjusting the allocation 1169 * count so scans can determine where free descriptors are located. 1170 * 1171 * MPSAFE - caller must be holding an exclusive spinlock on fdp 1172 */ 1173 static 1174 void 1175 fdreserve_locked(struct filedesc *fdp, int fd, int incr) 1176 { 1177 while (fd >= 0) { 1178 fdp->fd_files[fd].allocated += incr; 1179 KKASSERT(fdp->fd_files[fd].allocated >= 0); 1180 fd = left_ancestor(fd); 1181 } 1182 } 1183 1184 /* 1185 * Reserve a file descriptor for the process. If no error occurs, the 1186 * caller MUST at some point call fsetfd() or assign a file pointer 1187 * or dispose of the reservation. 1188 * 1189 * MPSAFE 1190 */ 1191 int 1192 fdalloc(struct proc *p, int want, int *result) 1193 { 1194 struct filedesc *fdp = p->p_fd; 1195 struct uidinfo *uip; 1196 int fd, rsize, rsum, node, lim; 1197 1198 /* 1199 * Check dtable size limit 1200 */ 1201 spin_lock(&p->p_limit->p_spin); 1202 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1203 lim = INT_MAX; 1204 else 1205 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1206 spin_unlock(&p->p_limit->p_spin); 1207 1208 if (lim > maxfilesperproc) 1209 lim = maxfilesperproc; 1210 if (lim < minfilesperproc) 1211 lim = minfilesperproc; 1212 if (want >= lim) 1213 return (EMFILE); 1214 1215 /* 1216 * Check that the user has not run out of descriptors (non-root only). 1217 * As a safety measure the dtable is allowed to have at least 1218 * minfilesperproc open fds regardless of the maxfilesperuser limit. 1219 */ 1220 if (p->p_ucred->cr_uid && fdp->fd_nfiles >= minfilesperproc) { 1221 uip = p->p_ucred->cr_uidinfo; 1222 if (uip->ui_openfiles > maxfilesperuser) { 1223 krateprintf(&krate_uidinfo, 1224 "Warning: user %d pid %d (%s) ran out of " 1225 "file descriptors (%d/%d)\n", 1226 p->p_ucred->cr_uid, (int)p->p_pid, 1227 p->p_comm, 1228 uip->ui_openfiles, maxfilesperuser); 1229 return(ENFILE); 1230 } 1231 } 1232 1233 /* 1234 * Grow the dtable if necessary 1235 */ 1236 spin_lock(&fdp->fd_spin); 1237 if (want >= fdp->fd_nfiles) 1238 fdgrow_locked(fdp, want); 1239 1240 /* 1241 * Search for a free descriptor starting at the higher 1242 * of want or fd_freefile. If that fails, consider 1243 * expanding the ofile array. 1244 * 1245 * NOTE! the 'allocated' field is a cumulative recursive allocation 1246 * count. If we happen to see a value of 0 then we can shortcut 1247 * our search. Otherwise we run through through the tree going 1248 * down branches we know have free descriptor(s) until we hit a 1249 * leaf node. The leaf node will be free but will not necessarily 1250 * have an allocated field of 0. 1251 */ 1252 retry: 1253 /* move up the tree looking for a subtree with a free node */ 1254 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); 1255 fd = right_ancestor(fd)) { 1256 if (fdp->fd_files[fd].allocated == 0) 1257 goto found; 1258 1259 rsize = right_subtree_size(fd); 1260 if (fdp->fd_files[fd].allocated == rsize) 1261 continue; /* right subtree full */ 1262 1263 /* 1264 * Free fd is in the right subtree of the tree rooted at fd. 1265 * Call that subtree R. Look for the smallest (leftmost) 1266 * subtree of R with an unallocated fd: continue moving 1267 * down the left branch until encountering a full left 1268 * subtree, then move to the right. 1269 */ 1270 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 1271 node = fd + rsize; 1272 rsum += fdp->fd_files[node].allocated; 1273 if (fdp->fd_files[fd].allocated == rsum + rsize) { 1274 fd = node; /* move to the right */ 1275 if (fdp->fd_files[node].allocated == 0) 1276 goto found; 1277 rsum = 0; 1278 } 1279 } 1280 goto found; 1281 } 1282 1283 /* 1284 * No space in current array. Expand? 1285 */ 1286 if (fdp->fd_nfiles >= lim) { 1287 spin_unlock(&fdp->fd_spin); 1288 return (EMFILE); 1289 } 1290 fdgrow_locked(fdp, want); 1291 goto retry; 1292 1293 found: 1294 KKASSERT(fd < fdp->fd_nfiles); 1295 if (fd > fdp->fd_lastfile) 1296 fdp->fd_lastfile = fd; 1297 if (want <= fdp->fd_freefile) 1298 fdp->fd_freefile = fd; 1299 *result = fd; 1300 KKASSERT(fdp->fd_files[fd].fp == NULL); 1301 KKASSERT(fdp->fd_files[fd].reserved == 0); 1302 fdp->fd_files[fd].fileflags = 0; 1303 fdp->fd_files[fd].reserved = 1; 1304 fdreserve_locked(fdp, fd, 1); 1305 spin_unlock(&fdp->fd_spin); 1306 return (0); 1307 } 1308 1309 /* 1310 * Check to see whether n user file descriptors 1311 * are available to the process p. 1312 * 1313 * MPSAFE 1314 */ 1315 int 1316 fdavail(struct proc *p, int n) 1317 { 1318 struct filedesc *fdp = p->p_fd; 1319 struct fdnode *fdnode; 1320 int i, lim, last; 1321 1322 spin_lock(&p->p_limit->p_spin); 1323 if (p->p_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1324 lim = INT_MAX; 1325 else 1326 lim = (int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 1327 spin_unlock(&p->p_limit->p_spin); 1328 1329 if (lim > maxfilesperproc) 1330 lim = maxfilesperproc; 1331 if (lim < minfilesperproc) 1332 lim = minfilesperproc; 1333 1334 spin_lock(&fdp->fd_spin); 1335 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { 1336 spin_unlock(&fdp->fd_spin); 1337 return (1); 1338 } 1339 last = min(fdp->fd_nfiles, lim); 1340 fdnode = &fdp->fd_files[fdp->fd_freefile]; 1341 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { 1342 if (fdnode->fp == NULL && --n <= 0) { 1343 spin_unlock(&fdp->fd_spin); 1344 return (1); 1345 } 1346 } 1347 spin_unlock(&fdp->fd_spin); 1348 return (0); 1349 } 1350 1351 /* 1352 * Revoke open descriptors referencing (f_data, f_type) 1353 * 1354 * Any revoke executed within a prison is only able to 1355 * revoke descriptors for processes within that prison. 1356 * 1357 * Returns 0 on success or an error code. 1358 */ 1359 struct fdrevoke_info { 1360 void *data; 1361 short type; 1362 short unused; 1363 int count; 1364 int intransit; 1365 struct ucred *cred; 1366 struct file *nfp; 1367 }; 1368 1369 static int fdrevoke_check_callback(struct file *fp, void *vinfo); 1370 static int fdrevoke_proc_callback(struct proc *p, void *vinfo); 1371 1372 int 1373 fdrevoke(void *f_data, short f_type, struct ucred *cred) 1374 { 1375 struct fdrevoke_info info; 1376 int error; 1377 1378 bzero(&info, sizeof(info)); 1379 info.data = f_data; 1380 info.type = f_type; 1381 info.cred = cred; 1382 error = falloc(NULL, &info.nfp, NULL); 1383 if (error) 1384 return (error); 1385 1386 /* 1387 * Scan the file pointer table once. dups do not dup file pointers, 1388 * only descriptors, so there is no leak. Set FREVOKED on the fps 1389 * being revoked. 1390 */ 1391 allfiles_scan_exclusive(fdrevoke_check_callback, &info); 1392 1393 /* 1394 * If any fps were marked track down the related descriptors 1395 * and close them. Any dup()s at this point will notice 1396 * the FREVOKED already set in the fp and do the right thing. 1397 * 1398 * Any fps with non-zero msgcounts (aka sent over a unix-domain 1399 * socket) bumped the intransit counter and will require a 1400 * scan. Races against fps leaving the socket are closed by 1401 * the socket code checking for FREVOKED. 1402 */ 1403 if (info.count) 1404 allproc_scan(fdrevoke_proc_callback, &info); 1405 if (info.intransit) 1406 unp_revoke_gc(info.nfp); 1407 fdrop(info.nfp); 1408 return(0); 1409 } 1410 1411 /* 1412 * Locate matching file pointers directly. 1413 * 1414 * WARNING: allfiles_scan_exclusive() holds a spinlock through these calls! 1415 */ 1416 static int 1417 fdrevoke_check_callback(struct file *fp, void *vinfo) 1418 { 1419 struct fdrevoke_info *info = vinfo; 1420 1421 /* 1422 * File pointers already flagged for revokation are skipped. 1423 */ 1424 if (fp->f_flag & FREVOKED) 1425 return(0); 1426 1427 /* 1428 * If revoking from a prison file pointers created outside of 1429 * that prison, or file pointers without creds, cannot be revoked. 1430 */ 1431 if (info->cred->cr_prison && 1432 (fp->f_cred == NULL || 1433 info->cred->cr_prison != fp->f_cred->cr_prison)) { 1434 return(0); 1435 } 1436 1437 /* 1438 * If the file pointer matches then mark it for revocation. The 1439 * flag is currently only used by unp_revoke_gc(). 1440 * 1441 * info->count is a heuristic and can race in a SMP environment. 1442 */ 1443 if (info->data == fp->f_data && info->type == fp->f_type) { 1444 atomic_set_int(&fp->f_flag, FREVOKED); 1445 info->count += fp->f_count; 1446 if (fp->f_msgcount) 1447 ++info->intransit; 1448 } 1449 return(0); 1450 } 1451 1452 /* 1453 * Locate matching file pointers via process descriptor tables. 1454 */ 1455 static int 1456 fdrevoke_proc_callback(struct proc *p, void *vinfo) 1457 { 1458 struct fdrevoke_info *info = vinfo; 1459 struct filedesc *fdp; 1460 struct file *fp; 1461 int n; 1462 1463 if (p->p_stat == SIDL || p->p_stat == SZOMB) 1464 return(0); 1465 if (info->cred->cr_prison && 1466 info->cred->cr_prison != p->p_ucred->cr_prison) { 1467 return(0); 1468 } 1469 1470 /* 1471 * If the controlling terminal of the process matches the 1472 * vnode being revoked we clear the controlling terminal. 1473 * 1474 * The normal spec_close() may not catch this because it 1475 * uses curproc instead of p. 1476 */ 1477 if (p->p_session && info->type == DTYPE_VNODE && 1478 info->data == p->p_session->s_ttyvp) { 1479 p->p_session->s_ttyvp = NULL; 1480 vrele(info->data); 1481 } 1482 1483 /* 1484 * Softref the fdp to prevent it from being destroyed 1485 */ 1486 spin_lock(&p->p_spin); 1487 if ((fdp = p->p_fd) == NULL) { 1488 spin_unlock(&p->p_spin); 1489 return(0); 1490 } 1491 atomic_add_int(&fdp->fd_softrefs, 1); 1492 spin_unlock(&p->p_spin); 1493 1494 /* 1495 * Locate and close any matching file descriptors. 1496 */ 1497 spin_lock(&fdp->fd_spin); 1498 for (n = 0; n < fdp->fd_nfiles; ++n) { 1499 if ((fp = fdp->fd_files[n].fp) == NULL) 1500 continue; 1501 if (fp->f_flag & FREVOKED) { 1502 fhold(info->nfp); 1503 fdp->fd_files[n].fp = info->nfp; 1504 spin_unlock(&fdp->fd_spin); 1505 knote_fdclose(fp, fdp, n); /* XXX */ 1506 closef(fp, p); 1507 spin_lock(&fdp->fd_spin); 1508 --info->count; 1509 } 1510 } 1511 spin_unlock(&fdp->fd_spin); 1512 atomic_subtract_int(&fdp->fd_softrefs, 1); 1513 return(0); 1514 } 1515 1516 /* 1517 * falloc: 1518 * Create a new open file structure and reserve a file decriptor 1519 * for the process that refers to it. 1520 * 1521 * Root creds are checked using lp, or assumed if lp is NULL. If 1522 * resultfd is non-NULL then lp must also be non-NULL. No file 1523 * descriptor is reserved (and no process context is needed) if 1524 * resultfd is NULL. 1525 * 1526 * A file pointer with a refcount of 1 is returned. Note that the 1527 * file pointer is NOT associated with the descriptor. If falloc 1528 * returns success, fsetfd() MUST be called to either associate the 1529 * file pointer or clear the reservation. 1530 * 1531 * MPSAFE 1532 */ 1533 int 1534 falloc(struct lwp *lp, struct file **resultfp, int *resultfd) 1535 { 1536 static struct timeval lastfail; 1537 static int curfail; 1538 struct file *fp; 1539 struct ucred *cred = lp ? lp->lwp_thread->td_ucred : proc0.p_ucred; 1540 int error; 1541 1542 fp = NULL; 1543 1544 /* 1545 * Handle filetable full issues and root overfill. 1546 */ 1547 if (nfiles >= maxfiles - maxfilesrootres && 1548 (cred->cr_ruid != 0 || nfiles >= maxfiles)) { 1549 if (ppsratecheck(&lastfail, &curfail, 1)) { 1550 kprintf("kern.maxfiles limit exceeded by uid %d, " 1551 "please see tuning(7).\n", 1552 cred->cr_ruid); 1553 } 1554 error = ENFILE; 1555 goto done; 1556 } 1557 1558 /* 1559 * Allocate a new file descriptor. 1560 */ 1561 fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); 1562 spin_init(&fp->f_spin, "falloc"); 1563 SLIST_INIT(&fp->f_klist); 1564 fp->f_count = 1; 1565 fp->f_ops = &badfileops; 1566 fp->f_seqcount = 1; 1567 fsetcred(fp, cred); 1568 spin_lock(&filehead_spin); 1569 nfiles++; 1570 LIST_INSERT_HEAD(&filehead, fp, f_list); 1571 spin_unlock(&filehead_spin); 1572 if (resultfd) { 1573 if ((error = fdalloc(lp->lwp_proc, 0, resultfd)) != 0) { 1574 fdrop(fp); 1575 fp = NULL; 1576 } 1577 } else { 1578 error = 0; 1579 } 1580 done: 1581 *resultfp = fp; 1582 return (error); 1583 } 1584 1585 /* 1586 * Check for races against a file descriptor by determining that the 1587 * file pointer is still associated with the specified file descriptor, 1588 * and a close is not currently in progress. 1589 * 1590 * MPSAFE 1591 */ 1592 int 1593 checkfdclosed(struct filedesc *fdp, int fd, struct file *fp) 1594 { 1595 int error; 1596 1597 spin_lock_shared(&fdp->fd_spin); 1598 if ((unsigned)fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) 1599 error = EBADF; 1600 else 1601 error = 0; 1602 spin_unlock_shared(&fdp->fd_spin); 1603 return (error); 1604 } 1605 1606 /* 1607 * Associate a file pointer with a previously reserved file descriptor. 1608 * This function always succeeds. 1609 * 1610 * If fp is NULL, the file descriptor is returned to the pool. 1611 */ 1612 1613 /* 1614 * MPSAFE (exclusive spinlock must be held on call) 1615 */ 1616 static void 1617 fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) 1618 { 1619 KKASSERT((unsigned)fd < fdp->fd_nfiles); 1620 KKASSERT(fdp->fd_files[fd].reserved != 0); 1621 if (fp) { 1622 fhold(fp); 1623 fdp->fd_files[fd].fp = fp; 1624 fdp->fd_files[fd].reserved = 0; 1625 } else { 1626 fdp->fd_files[fd].reserved = 0; 1627 fdreserve_locked(fdp, fd, -1); 1628 fdfixup_locked(fdp, fd); 1629 } 1630 } 1631 1632 /* 1633 * MPSAFE 1634 */ 1635 void 1636 fsetfd(struct filedesc *fdp, struct file *fp, int fd) 1637 { 1638 spin_lock(&fdp->fd_spin); 1639 fsetfd_locked(fdp, fp, fd); 1640 spin_unlock(&fdp->fd_spin); 1641 } 1642 1643 /* 1644 * MPSAFE (exclusive spinlock must be held on call) 1645 */ 1646 static 1647 struct file * 1648 funsetfd_locked(struct filedesc *fdp, int fd) 1649 { 1650 struct file *fp; 1651 1652 if ((unsigned)fd >= fdp->fd_nfiles) 1653 return (NULL); 1654 if ((fp = fdp->fd_files[fd].fp) == NULL) 1655 return (NULL); 1656 fdp->fd_files[fd].fp = NULL; 1657 fdp->fd_files[fd].fileflags = 0; 1658 1659 fdreserve_locked(fdp, fd, -1); 1660 fdfixup_locked(fdp, fd); 1661 return(fp); 1662 } 1663 1664 /* 1665 * MPSAFE 1666 */ 1667 int 1668 fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) 1669 { 1670 int error; 1671 1672 spin_lock(&fdp->fd_spin); 1673 if (((u_int)fd) >= fdp->fd_nfiles) { 1674 error = EBADF; 1675 } else if (fdp->fd_files[fd].fp == NULL) { 1676 error = EBADF; 1677 } else { 1678 *flagsp = fdp->fd_files[fd].fileflags; 1679 error = 0; 1680 } 1681 spin_unlock(&fdp->fd_spin); 1682 return (error); 1683 } 1684 1685 /* 1686 * MPSAFE 1687 */ 1688 int 1689 fsetfdflags(struct filedesc *fdp, int fd, int add_flags) 1690 { 1691 int error; 1692 1693 spin_lock(&fdp->fd_spin); 1694 if (((u_int)fd) >= fdp->fd_nfiles) { 1695 error = EBADF; 1696 } else if (fdp->fd_files[fd].fp == NULL) { 1697 error = EBADF; 1698 } else { 1699 fdp->fd_files[fd].fileflags |= add_flags; 1700 error = 0; 1701 } 1702 spin_unlock(&fdp->fd_spin); 1703 return (error); 1704 } 1705 1706 /* 1707 * MPSAFE 1708 */ 1709 int 1710 fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) 1711 { 1712 int error; 1713 1714 spin_lock(&fdp->fd_spin); 1715 if (((u_int)fd) >= fdp->fd_nfiles) { 1716 error = EBADF; 1717 } else if (fdp->fd_files[fd].fp == NULL) { 1718 error = EBADF; 1719 } else { 1720 fdp->fd_files[fd].fileflags &= ~rem_flags; 1721 error = 0; 1722 } 1723 spin_unlock(&fdp->fd_spin); 1724 return (error); 1725 } 1726 1727 /* 1728 * Set/Change/Clear the creds for a fp and synchronize the uidinfo. 1729 */ 1730 void 1731 fsetcred(struct file *fp, struct ucred *ncr) 1732 { 1733 struct ucred *ocr; 1734 struct uidinfo *uip; 1735 1736 ocr = fp->f_cred; 1737 if (ocr == NULL || ncr == NULL || ocr->cr_uidinfo != ncr->cr_uidinfo) { 1738 if (ocr) { 1739 uip = ocr->cr_uidinfo; 1740 atomic_add_int(&uip->ui_openfiles, -1); 1741 } 1742 if (ncr) { 1743 uip = ncr->cr_uidinfo; 1744 atomic_add_int(&uip->ui_openfiles, 1); 1745 } 1746 } 1747 if (ncr) 1748 crhold(ncr); 1749 fp->f_cred = ncr; 1750 if (ocr) 1751 crfree(ocr); 1752 } 1753 1754 /* 1755 * Free a file descriptor. 1756 */ 1757 static 1758 void 1759 ffree(struct file *fp) 1760 { 1761 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 1762 spin_lock(&filehead_spin); 1763 LIST_REMOVE(fp, f_list); 1764 nfiles--; 1765 spin_unlock(&filehead_spin); 1766 fsetcred(fp, NULL); 1767 if (fp->f_nchandle.ncp) 1768 cache_drop(&fp->f_nchandle); 1769 kfree(fp, M_FILE); 1770 } 1771 1772 /* 1773 * called from init_main, initialize filedesc0 for proc0. 1774 */ 1775 void 1776 fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) 1777 { 1778 p0->p_fd = fdp0; 1779 p0->p_fdtol = NULL; 1780 fdp0->fd_refcnt = 1; 1781 fdp0->fd_cmask = cmask; 1782 fdp0->fd_files = fdp0->fd_builtin_files; 1783 fdp0->fd_nfiles = NDFILE; 1784 fdp0->fd_lastfile = -1; 1785 spin_init(&fdp0->fd_spin, "fdinitbootstrap"); 1786 } 1787 1788 /* 1789 * Build a new filedesc structure. 1790 * 1791 * NOT MPSAFE (vref) 1792 */ 1793 struct filedesc * 1794 fdinit(struct proc *p) 1795 { 1796 struct filedesc *newfdp; 1797 struct filedesc *fdp = p->p_fd; 1798 1799 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); 1800 spin_lock(&fdp->fd_spin); 1801 if (fdp->fd_cdir) { 1802 newfdp->fd_cdir = fdp->fd_cdir; 1803 vref(newfdp->fd_cdir); 1804 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1805 } 1806 1807 /* 1808 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 1809 * proc0, but should unconditionally exist in other processes. 1810 */ 1811 if (fdp->fd_rdir) { 1812 newfdp->fd_rdir = fdp->fd_rdir; 1813 vref(newfdp->fd_rdir); 1814 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1815 } 1816 if (fdp->fd_jdir) { 1817 newfdp->fd_jdir = fdp->fd_jdir; 1818 vref(newfdp->fd_jdir); 1819 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1820 } 1821 spin_unlock(&fdp->fd_spin); 1822 1823 /* Create the file descriptor table. */ 1824 newfdp->fd_refcnt = 1; 1825 newfdp->fd_cmask = cmask; 1826 newfdp->fd_files = newfdp->fd_builtin_files; 1827 newfdp->fd_nfiles = NDFILE; 1828 newfdp->fd_lastfile = -1; 1829 spin_init(&newfdp->fd_spin, "fdinit"); 1830 1831 return (newfdp); 1832 } 1833 1834 /* 1835 * Share a filedesc structure. 1836 * 1837 * MPSAFE 1838 */ 1839 struct filedesc * 1840 fdshare(struct proc *p) 1841 { 1842 struct filedesc *fdp; 1843 1844 fdp = p->p_fd; 1845 spin_lock(&fdp->fd_spin); 1846 fdp->fd_refcnt++; 1847 spin_unlock(&fdp->fd_spin); 1848 return (fdp); 1849 } 1850 1851 /* 1852 * Copy a filedesc structure. 1853 * 1854 * MPSAFE 1855 */ 1856 int 1857 fdcopy(struct proc *p, struct filedesc **fpp) 1858 { 1859 struct filedesc *fdp = p->p_fd; 1860 struct filedesc *newfdp; 1861 struct fdnode *fdnode; 1862 int i; 1863 int ni; 1864 1865 /* 1866 * Certain daemons might not have file descriptors. 1867 */ 1868 if (fdp == NULL) 1869 return (0); 1870 1871 /* 1872 * Allocate the new filedesc and fd_files[] array. This can race 1873 * with operations by other threads on the fdp so we have to be 1874 * careful. 1875 */ 1876 newfdp = kmalloc(sizeof(struct filedesc), 1877 M_FILEDESC, M_WAITOK | M_ZERO | M_NULLOK); 1878 if (newfdp == NULL) { 1879 *fpp = NULL; 1880 return (-1); 1881 } 1882 again: 1883 spin_lock(&fdp->fd_spin); 1884 if (fdp->fd_lastfile < NDFILE) { 1885 newfdp->fd_files = newfdp->fd_builtin_files; 1886 i = NDFILE; 1887 } else { 1888 /* 1889 * We have to allocate (N^2-1) entries for our in-place 1890 * binary tree. Allow the table to shrink. 1891 */ 1892 i = fdp->fd_nfiles; 1893 ni = (i - 1) / 2; 1894 while (ni > fdp->fd_lastfile && ni > NDFILE) { 1895 i = ni; 1896 ni = (i - 1) / 2; 1897 } 1898 spin_unlock(&fdp->fd_spin); 1899 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), 1900 M_FILEDESC, M_WAITOK | M_ZERO); 1901 1902 /* 1903 * Check for race, retry 1904 */ 1905 spin_lock(&fdp->fd_spin); 1906 if (i <= fdp->fd_lastfile) { 1907 spin_unlock(&fdp->fd_spin); 1908 kfree(newfdp->fd_files, M_FILEDESC); 1909 goto again; 1910 } 1911 } 1912 1913 /* 1914 * Dup the remaining fields. vref() and cache_hold() can be 1915 * safely called while holding the read spinlock on fdp. 1916 * 1917 * The read spinlock on fdp is still being held. 1918 * 1919 * NOTE: vref and cache_hold calls for the case where the vnode 1920 * or cache entry already has at least one ref may be called 1921 * while holding spin locks. 1922 */ 1923 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { 1924 vref(newfdp->fd_cdir); 1925 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 1926 } 1927 /* 1928 * We must check for fd_rdir here, at least for now because 1929 * the init process is created before we have access to the 1930 * rootvode to take a reference to it. 1931 */ 1932 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { 1933 vref(newfdp->fd_rdir); 1934 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 1935 } 1936 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { 1937 vref(newfdp->fd_jdir); 1938 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 1939 } 1940 newfdp->fd_refcnt = 1; 1941 newfdp->fd_nfiles = i; 1942 newfdp->fd_lastfile = fdp->fd_lastfile; 1943 newfdp->fd_freefile = fdp->fd_freefile; 1944 newfdp->fd_cmask = fdp->fd_cmask; 1945 spin_init(&newfdp->fd_spin, "fdcopy"); 1946 1947 /* 1948 * Copy the descriptor table through (i). This also copies the 1949 * allocation state. Then go through and ref the file pointers 1950 * and clean up any KQ descriptors. 1951 * 1952 * kq descriptors cannot be copied. Since we haven't ref'd the 1953 * copied files yet we can ignore the return value from funsetfd(). 1954 * 1955 * The read spinlock on fdp is still being held. 1956 */ 1957 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); 1958 for (i = 0 ; i < newfdp->fd_nfiles; ++i) { 1959 fdnode = &newfdp->fd_files[i]; 1960 if (fdnode->reserved) { 1961 fdreserve_locked(newfdp, i, -1); 1962 fdnode->reserved = 0; 1963 fdfixup_locked(newfdp, i); 1964 } else if (fdnode->fp) { 1965 if (fdnode->fp->f_type == DTYPE_KQUEUE) { 1966 (void)funsetfd_locked(newfdp, i); 1967 } else { 1968 fhold(fdnode->fp); 1969 } 1970 } 1971 } 1972 spin_unlock(&fdp->fd_spin); 1973 *fpp = newfdp; 1974 return (0); 1975 } 1976 1977 /* 1978 * Release a filedesc structure. 1979 * 1980 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) 1981 */ 1982 void 1983 fdfree(struct proc *p, struct filedesc *repl) 1984 { 1985 struct filedesc *fdp; 1986 struct fdnode *fdnode; 1987 int i; 1988 struct filedesc_to_leader *fdtol; 1989 struct file *fp; 1990 struct vnode *vp; 1991 struct flock lf; 1992 1993 /* 1994 * Certain daemons might not have file descriptors. 1995 */ 1996 fdp = p->p_fd; 1997 if (fdp == NULL) { 1998 p->p_fd = repl; 1999 return; 2000 } 2001 2002 /* 2003 * Severe messing around to follow. 2004 */ 2005 spin_lock(&fdp->fd_spin); 2006 2007 /* Check for special need to clear POSIX style locks */ 2008 fdtol = p->p_fdtol; 2009 if (fdtol != NULL) { 2010 KASSERT(fdtol->fdl_refcount > 0, 2011 ("filedesc_to_refcount botch: fdl_refcount=%d", 2012 fdtol->fdl_refcount)); 2013 if (fdtol->fdl_refcount == 1 && 2014 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 2015 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2016 fdnode = &fdp->fd_files[i]; 2017 if (fdnode->fp == NULL || 2018 fdnode->fp->f_type != DTYPE_VNODE) { 2019 continue; 2020 } 2021 fp = fdnode->fp; 2022 fhold(fp); 2023 spin_unlock(&fdp->fd_spin); 2024 2025 lf.l_whence = SEEK_SET; 2026 lf.l_start = 0; 2027 lf.l_len = 0; 2028 lf.l_type = F_UNLCK; 2029 vp = (struct vnode *)fp->f_data; 2030 (void) VOP_ADVLOCK(vp, 2031 (caddr_t)p->p_leader, 2032 F_UNLCK, 2033 &lf, 2034 F_POSIX); 2035 fdrop(fp); 2036 spin_lock(&fdp->fd_spin); 2037 } 2038 } 2039 retry: 2040 if (fdtol->fdl_refcount == 1) { 2041 if (fdp->fd_holdleaderscount > 0 && 2042 (p->p_leader->p_flags & P_ADVLOCK) != 0) { 2043 /* 2044 * close() or do_dup() has cleared a reference 2045 * in a shared file descriptor table. 2046 */ 2047 fdp->fd_holdleaderswakeup = 1; 2048 ssleep(&fdp->fd_holdleaderscount, 2049 &fdp->fd_spin, 0, "fdlhold", 0); 2050 goto retry; 2051 } 2052 if (fdtol->fdl_holdcount > 0) { 2053 /* 2054 * Ensure that fdtol->fdl_leader 2055 * remains valid in closef(). 2056 */ 2057 fdtol->fdl_wakeup = 1; 2058 ssleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); 2059 goto retry; 2060 } 2061 } 2062 fdtol->fdl_refcount--; 2063 if (fdtol->fdl_refcount == 0 && 2064 fdtol->fdl_holdcount == 0) { 2065 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2066 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2067 } else { 2068 fdtol = NULL; 2069 } 2070 p->p_fdtol = NULL; 2071 if (fdtol != NULL) { 2072 spin_unlock(&fdp->fd_spin); 2073 kfree(fdtol, M_FILEDESC_TO_LEADER); 2074 spin_lock(&fdp->fd_spin); 2075 } 2076 } 2077 if (--fdp->fd_refcnt > 0) { 2078 spin_unlock(&fdp->fd_spin); 2079 spin_lock(&p->p_spin); 2080 p->p_fd = repl; 2081 spin_unlock(&p->p_spin); 2082 return; 2083 } 2084 2085 /* 2086 * Even though we are the last reference to the structure allproc 2087 * scans may still reference the structure. Maintain proper 2088 * locks until we can replace p->p_fd. 2089 * 2090 * Also note that kqueue's closef still needs to reference the 2091 * fdp via p->p_fd, so we have to close the descriptors before 2092 * we replace p->p_fd. 2093 */ 2094 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2095 if (fdp->fd_files[i].fp) { 2096 fp = funsetfd_locked(fdp, i); 2097 if (fp) { 2098 spin_unlock(&fdp->fd_spin); 2099 if (SLIST_FIRST(&fp->f_klist)) 2100 knote_fdclose(fp, fdp, i); 2101 closef(fp, p); 2102 spin_lock(&fdp->fd_spin); 2103 } 2104 } 2105 } 2106 spin_unlock(&fdp->fd_spin); 2107 2108 /* 2109 * Interlock against an allproc scan operations (typically frevoke). 2110 */ 2111 spin_lock(&p->p_spin); 2112 p->p_fd = repl; 2113 spin_unlock(&p->p_spin); 2114 2115 /* 2116 * Wait for any softrefs to go away. This race rarely occurs so 2117 * we can use a non-critical-path style poll/sleep loop. The 2118 * race only occurs against allproc scans. 2119 * 2120 * No new softrefs can occur with the fdp disconnected from the 2121 * process. 2122 */ 2123 if (fdp->fd_softrefs) { 2124 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid); 2125 while (fdp->fd_softrefs) 2126 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1); 2127 } 2128 2129 if (fdp->fd_files != fdp->fd_builtin_files) 2130 kfree(fdp->fd_files, M_FILEDESC); 2131 if (fdp->fd_cdir) { 2132 cache_drop(&fdp->fd_ncdir); 2133 vrele(fdp->fd_cdir); 2134 } 2135 if (fdp->fd_rdir) { 2136 cache_drop(&fdp->fd_nrdir); 2137 vrele(fdp->fd_rdir); 2138 } 2139 if (fdp->fd_jdir) { 2140 cache_drop(&fdp->fd_njdir); 2141 vrele(fdp->fd_jdir); 2142 } 2143 kfree(fdp, M_FILEDESC); 2144 } 2145 2146 /* 2147 * Retrieve and reference the file pointer associated with a descriptor. 2148 * 2149 * MPSAFE 2150 */ 2151 struct file * 2152 holdfp(struct filedesc *fdp, int fd, int flag) 2153 { 2154 struct file* fp; 2155 2156 spin_lock_shared(&fdp->fd_spin); 2157 if (((u_int)fd) >= fdp->fd_nfiles) { 2158 fp = NULL; 2159 goto done; 2160 } 2161 if ((fp = fdp->fd_files[fd].fp) == NULL) 2162 goto done; 2163 if ((fp->f_flag & flag) == 0 && flag != -1) { 2164 fp = NULL; 2165 goto done; 2166 } 2167 fhold(fp); 2168 done: 2169 spin_unlock_shared(&fdp->fd_spin); 2170 return (fp); 2171 } 2172 2173 /* 2174 * holdsock() - load the struct file pointer associated 2175 * with a socket into *fpp. If an error occurs, non-zero 2176 * will be returned and *fpp will be set to NULL. 2177 * 2178 * MPSAFE 2179 */ 2180 int 2181 holdsock(struct filedesc *fdp, int fd, struct file **fpp) 2182 { 2183 struct file *fp; 2184 int error; 2185 2186 spin_lock_shared(&fdp->fd_spin); 2187 if ((unsigned)fd >= fdp->fd_nfiles) { 2188 error = EBADF; 2189 fp = NULL; 2190 goto done; 2191 } 2192 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2193 error = EBADF; 2194 goto done; 2195 } 2196 if (fp->f_type != DTYPE_SOCKET) { 2197 error = ENOTSOCK; 2198 goto done; 2199 } 2200 fhold(fp); 2201 error = 0; 2202 done: 2203 spin_unlock_shared(&fdp->fd_spin); 2204 *fpp = fp; 2205 return (error); 2206 } 2207 2208 /* 2209 * Convert a user file descriptor to a held file pointer. 2210 * 2211 * MPSAFE 2212 */ 2213 int 2214 holdvnode(struct filedesc *fdp, int fd, struct file **fpp) 2215 { 2216 struct file *fp; 2217 int error; 2218 2219 spin_lock_shared(&fdp->fd_spin); 2220 if ((unsigned)fd >= fdp->fd_nfiles) { 2221 error = EBADF; 2222 fp = NULL; 2223 goto done; 2224 } 2225 if ((fp = fdp->fd_files[fd].fp) == NULL) { 2226 error = EBADF; 2227 goto done; 2228 } 2229 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2230 fp = NULL; 2231 error = EINVAL; 2232 goto done; 2233 } 2234 fhold(fp); 2235 error = 0; 2236 done: 2237 spin_unlock_shared(&fdp->fd_spin); 2238 *fpp = fp; 2239 return (error); 2240 } 2241 2242 /* 2243 * For setugid programs, we don't want to people to use that setugidness 2244 * to generate error messages which write to a file which otherwise would 2245 * otherwise be off-limits to the process. 2246 * 2247 * This is a gross hack to plug the hole. A better solution would involve 2248 * a special vop or other form of generalized access control mechanism. We 2249 * go ahead and just reject all procfs file systems accesses as dangerous. 2250 * 2251 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 2252 * sufficient. We also don't for check setugidness since we know we are. 2253 */ 2254 static int 2255 is_unsafe(struct file *fp) 2256 { 2257 if (fp->f_type == DTYPE_VNODE && 2258 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 2259 return (1); 2260 return (0); 2261 } 2262 2263 /* 2264 * Make this setguid thing safe, if at all possible. 2265 * 2266 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2267 */ 2268 void 2269 setugidsafety(struct proc *p) 2270 { 2271 struct filedesc *fdp = p->p_fd; 2272 int i; 2273 2274 /* Certain daemons might not have file descriptors. */ 2275 if (fdp == NULL) 2276 return; 2277 2278 /* 2279 * note: fdp->fd_files may be reallocated out from under us while 2280 * we are blocked in a close. Be careful! 2281 */ 2282 for (i = 0; i <= fdp->fd_lastfile; i++) { 2283 if (i > 2) 2284 break; 2285 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { 2286 struct file *fp; 2287 2288 /* 2289 * NULL-out descriptor prior to close to avoid 2290 * a race while close blocks. 2291 */ 2292 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2293 knote_fdclose(fp, fdp, i); 2294 closef(fp, p); 2295 } 2296 } 2297 } 2298 } 2299 2300 /* 2301 * Close any files on exec? 2302 * 2303 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2304 */ 2305 void 2306 fdcloseexec(struct proc *p) 2307 { 2308 struct filedesc *fdp = p->p_fd; 2309 int i; 2310 2311 /* Certain daemons might not have file descriptors. */ 2312 if (fdp == NULL) 2313 return; 2314 2315 /* 2316 * We cannot cache fd_files since operations may block and rip 2317 * them out from under us. 2318 */ 2319 for (i = 0; i <= fdp->fd_lastfile; i++) { 2320 if (fdp->fd_files[i].fp != NULL && 2321 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { 2322 struct file *fp; 2323 2324 /* 2325 * NULL-out descriptor prior to close to avoid 2326 * a race while close blocks. 2327 */ 2328 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2329 knote_fdclose(fp, fdp, i); 2330 closef(fp, p); 2331 } 2332 } 2333 } 2334 } 2335 2336 /* 2337 * It is unsafe for set[ug]id processes to be started with file 2338 * descriptors 0..2 closed, as these descriptors are given implicit 2339 * significance in the Standard C library. fdcheckstd() will create a 2340 * descriptor referencing /dev/null for each of stdin, stdout, and 2341 * stderr that is not already open. 2342 * 2343 * NOT MPSAFE - calls falloc, vn_open, etc 2344 */ 2345 int 2346 fdcheckstd(struct lwp *lp) 2347 { 2348 struct nlookupdata nd; 2349 struct filedesc *fdp; 2350 struct file *fp; 2351 int retval; 2352 int i, error, flags, devnull; 2353 2354 fdp = lp->lwp_proc->p_fd; 2355 if (fdp == NULL) 2356 return (0); 2357 devnull = -1; 2358 error = 0; 2359 for (i = 0; i < 3; i++) { 2360 if (fdp->fd_files[i].fp != NULL) 2361 continue; 2362 if (devnull < 0) { 2363 if ((error = falloc(lp, &fp, &devnull)) != 0) 2364 break; 2365 2366 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 2367 NLC_FOLLOW|NLC_LOCKVP); 2368 flags = FREAD | FWRITE; 2369 if (error == 0) 2370 error = vn_open(&nd, fp, flags, 0); 2371 if (error == 0) 2372 fsetfd(fdp, fp, devnull); 2373 else 2374 fsetfd(fdp, NULL, devnull); 2375 fdrop(fp); 2376 nlookup_done(&nd); 2377 if (error) 2378 break; 2379 KKASSERT(i == devnull); 2380 } else { 2381 error = kern_dup(DUP_FIXED, devnull, i, &retval); 2382 if (error != 0) 2383 break; 2384 } 2385 } 2386 return (error); 2387 } 2388 2389 /* 2390 * Internal form of close. 2391 * Decrement reference count on file structure. 2392 * Note: td and/or p may be NULL when closing a file 2393 * that was being passed in a message. 2394 * 2395 * MPALMOSTSAFE - acquires mplock for VOP operations 2396 */ 2397 int 2398 closef(struct file *fp, struct proc *p) 2399 { 2400 struct vnode *vp; 2401 struct flock lf; 2402 struct filedesc_to_leader *fdtol; 2403 2404 if (fp == NULL) 2405 return (0); 2406 2407 /* 2408 * POSIX record locking dictates that any close releases ALL 2409 * locks owned by this process. This is handled by setting 2410 * a flag in the unlock to free ONLY locks obeying POSIX 2411 * semantics, and not to free BSD-style file locks. 2412 * If the descriptor was in a message, POSIX-style locks 2413 * aren't passed with the descriptor. 2414 */ 2415 if (p != NULL && fp->f_type == DTYPE_VNODE && 2416 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2417 ) { 2418 if ((p->p_leader->p_flags & P_ADVLOCK) != 0) { 2419 lf.l_whence = SEEK_SET; 2420 lf.l_start = 0; 2421 lf.l_len = 0; 2422 lf.l_type = F_UNLCK; 2423 vp = (struct vnode *)fp->f_data; 2424 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 2425 &lf, F_POSIX); 2426 } 2427 fdtol = p->p_fdtol; 2428 if (fdtol != NULL) { 2429 lwkt_gettoken(&p->p_token); 2430 /* 2431 * Handle special case where file descriptor table 2432 * is shared between multiple process leaders. 2433 */ 2434 for (fdtol = fdtol->fdl_next; 2435 fdtol != p->p_fdtol; 2436 fdtol = fdtol->fdl_next) { 2437 if ((fdtol->fdl_leader->p_flags & 2438 P_ADVLOCK) == 0) 2439 continue; 2440 fdtol->fdl_holdcount++; 2441 lf.l_whence = SEEK_SET; 2442 lf.l_start = 0; 2443 lf.l_len = 0; 2444 lf.l_type = F_UNLCK; 2445 vp = (struct vnode *)fp->f_data; 2446 (void) VOP_ADVLOCK(vp, 2447 (caddr_t)fdtol->fdl_leader, 2448 F_UNLCK, &lf, F_POSIX); 2449 fdtol->fdl_holdcount--; 2450 if (fdtol->fdl_holdcount == 0 && 2451 fdtol->fdl_wakeup != 0) { 2452 fdtol->fdl_wakeup = 0; 2453 wakeup(fdtol); 2454 } 2455 } 2456 lwkt_reltoken(&p->p_token); 2457 } 2458 } 2459 return (fdrop(fp)); 2460 } 2461 2462 /* 2463 * MPSAFE 2464 * 2465 * fhold() can only be called if f_count is already at least 1 (i.e. the 2466 * caller of fhold() already has a reference to the file pointer in some 2467 * manner or other). 2468 * 2469 * f_count is not spin-locked. Instead, atomic ops are used for 2470 * incrementing, decrementing, and handling the 1->0 transition. 2471 */ 2472 void 2473 fhold(struct file *fp) 2474 { 2475 atomic_add_int(&fp->f_count, 1); 2476 } 2477 2478 /* 2479 * fdrop() - drop a reference to a descriptor 2480 * 2481 * MPALMOSTSAFE - acquires mplock for final close sequence 2482 */ 2483 int 2484 fdrop(struct file *fp) 2485 { 2486 struct flock lf; 2487 struct vnode *vp; 2488 int error; 2489 2490 /* 2491 * A combined fetch and subtract is needed to properly detect 2492 * 1->0 transitions, otherwise two cpus dropping from a ref 2493 * count of 2 might both try to run the 1->0 code. 2494 */ 2495 if (atomic_fetchadd_int(&fp->f_count, -1) > 1) 2496 return (0); 2497 2498 KKASSERT(SLIST_FIRST(&fp->f_klist) == NULL); 2499 2500 /* 2501 * The last reference has gone away, we own the fp structure free 2502 * and clear. 2503 */ 2504 if (fp->f_count < 0) 2505 panic("fdrop: count < 0"); 2506 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && 2507 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2508 ) { 2509 lf.l_whence = SEEK_SET; 2510 lf.l_start = 0; 2511 lf.l_len = 0; 2512 lf.l_type = F_UNLCK; 2513 vp = (struct vnode *)fp->f_data; 2514 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2515 } 2516 if (fp->f_ops != &badfileops) 2517 error = fo_close(fp); 2518 else 2519 error = 0; 2520 ffree(fp); 2521 return (error); 2522 } 2523 2524 /* 2525 * Apply an advisory lock on a file descriptor. 2526 * 2527 * Just attempt to get a record lock of the requested type on 2528 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2529 * 2530 * MPALMOSTSAFE 2531 */ 2532 int 2533 sys_flock(struct flock_args *uap) 2534 { 2535 struct proc *p = curproc; 2536 struct file *fp; 2537 struct vnode *vp; 2538 struct flock lf; 2539 int error; 2540 2541 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) 2542 return (EBADF); 2543 if (fp->f_type != DTYPE_VNODE) { 2544 error = EOPNOTSUPP; 2545 goto done; 2546 } 2547 vp = (struct vnode *)fp->f_data; 2548 lf.l_whence = SEEK_SET; 2549 lf.l_start = 0; 2550 lf.l_len = 0; 2551 if (uap->how & LOCK_UN) { 2552 lf.l_type = F_UNLCK; 2553 fp->f_flag &= ~FHASLOCK; 2554 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 2555 goto done; 2556 } 2557 if (uap->how & LOCK_EX) 2558 lf.l_type = F_WRLCK; 2559 else if (uap->how & LOCK_SH) 2560 lf.l_type = F_RDLCK; 2561 else { 2562 error = EBADF; 2563 goto done; 2564 } 2565 fp->f_flag |= FHASLOCK; 2566 if (uap->how & LOCK_NB) 2567 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); 2568 else 2569 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); 2570 done: 2571 fdrop(fp); 2572 return (error); 2573 } 2574 2575 /* 2576 * File Descriptor pseudo-device driver (/dev/fd/). 2577 * 2578 * Opening minor device N dup()s the file (if any) connected to file 2579 * descriptor N belonging to the calling process. Note that this driver 2580 * consists of only the ``open()'' routine, because all subsequent 2581 * references to this file will be direct to the other driver. 2582 */ 2583 static int 2584 fdopen(struct dev_open_args *ap) 2585 { 2586 thread_t td = curthread; 2587 2588 KKASSERT(td->td_lwp != NULL); 2589 2590 /* 2591 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the 2592 * the file descriptor being sought for duplication. The error 2593 * return ensures that the vnode for this device will be released 2594 * by vn_open. Open will detect this special error and take the 2595 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2596 * will simply report the error. 2597 */ 2598 td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev); 2599 return (ENODEV); 2600 } 2601 2602 /* 2603 * The caller has reserved the file descriptor dfd for us. On success we 2604 * must fsetfd() it. On failure the caller will clean it up. 2605 * 2606 * MPSAFE 2607 */ 2608 int 2609 dupfdopen(struct filedesc *fdp, int dfd, int sfd, int mode, int error) 2610 { 2611 struct file *wfp; 2612 struct file *xfp; 2613 int werror; 2614 2615 if ((wfp = holdfp(fdp, sfd, -1)) == NULL) 2616 return (EBADF); 2617 2618 /* 2619 * Close a revoke/dup race. Duping a descriptor marked as revoked 2620 * will dup a dummy descriptor instead of the real one. 2621 */ 2622 if (wfp->f_flag & FREVOKED) { 2623 kprintf("Warning: attempt to dup() a revoked descriptor\n"); 2624 fdrop(wfp); 2625 wfp = NULL; 2626 werror = falloc(NULL, &wfp, NULL); 2627 if (werror) 2628 return (werror); 2629 } 2630 2631 /* 2632 * There are two cases of interest here. 2633 * 2634 * For ENODEV simply dup sfd to file descriptor dfd and return. 2635 * 2636 * For ENXIO steal away the file structure from sfd and store it 2637 * dfd. sfd is effectively closed by this operation. 2638 * 2639 * Any other error code is just returned. 2640 */ 2641 switch (error) { 2642 case ENODEV: 2643 /* 2644 * Check that the mode the file is being opened for is a 2645 * subset of the mode of the existing descriptor. 2646 */ 2647 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2648 error = EACCES; 2649 break; 2650 } 2651 spin_lock(&fdp->fd_spin); 2652 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2653 fsetfd_locked(fdp, wfp, dfd); 2654 spin_unlock(&fdp->fd_spin); 2655 error = 0; 2656 break; 2657 case ENXIO: 2658 /* 2659 * Steal away the file pointer from dfd, and stuff it into indx. 2660 */ 2661 spin_lock(&fdp->fd_spin); 2662 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; 2663 fsetfd(fdp, wfp, dfd); 2664 if ((xfp = funsetfd_locked(fdp, sfd)) != NULL) { 2665 spin_unlock(&fdp->fd_spin); 2666 fdrop(xfp); 2667 } else { 2668 spin_unlock(&fdp->fd_spin); 2669 } 2670 error = 0; 2671 break; 2672 default: 2673 break; 2674 } 2675 fdrop(wfp); 2676 return (error); 2677 } 2678 2679 /* 2680 * NOT MPSAFE - I think these refer to a common file descriptor table 2681 * and we need to spinlock that to link fdtol in. 2682 */ 2683 struct filedesc_to_leader * 2684 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2685 struct proc *leader) 2686 { 2687 struct filedesc_to_leader *fdtol; 2688 2689 fdtol = kmalloc(sizeof(struct filedesc_to_leader), 2690 M_FILEDESC_TO_LEADER, M_WAITOK | M_ZERO); 2691 fdtol->fdl_refcount = 1; 2692 fdtol->fdl_holdcount = 0; 2693 fdtol->fdl_wakeup = 0; 2694 fdtol->fdl_leader = leader; 2695 if (old != NULL) { 2696 fdtol->fdl_next = old->fdl_next; 2697 fdtol->fdl_prev = old; 2698 old->fdl_next = fdtol; 2699 fdtol->fdl_next->fdl_prev = fdtol; 2700 } else { 2701 fdtol->fdl_next = fdtol; 2702 fdtol->fdl_prev = fdtol; 2703 } 2704 return fdtol; 2705 } 2706 2707 /* 2708 * Scan all file pointers in the system. The callback is made with 2709 * the master list spinlock held exclusively. 2710 * 2711 * MPSAFE 2712 */ 2713 void 2714 allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) 2715 { 2716 struct file *fp; 2717 int res; 2718 2719 spin_lock(&filehead_spin); 2720 LIST_FOREACH(fp, &filehead, f_list) { 2721 res = callback(fp, data); 2722 if (res < 0) 2723 break; 2724 } 2725 spin_unlock(&filehead_spin); 2726 } 2727 2728 /* 2729 * Get file structures. 2730 * 2731 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) 2732 */ 2733 2734 struct sysctl_kern_file_info { 2735 int count; 2736 int error; 2737 struct sysctl_req *req; 2738 }; 2739 2740 static int sysctl_kern_file_callback(struct proc *p, void *data); 2741 2742 static int 2743 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2744 { 2745 struct sysctl_kern_file_info info; 2746 2747 /* 2748 * Note: because the number of file descriptors is calculated 2749 * in different ways for sizing vs returning the data, 2750 * there is information leakage from the first loop. However, 2751 * it is of a similar order of magnitude to the leakage from 2752 * global system statistics such as kern.openfiles. 2753 * 2754 * When just doing a count, note that we cannot just count 2755 * the elements and add f_count via the filehead list because 2756 * threaded processes share their descriptor table and f_count might 2757 * still be '1' in that case. 2758 * 2759 * Since the SYSCTL op can block, we must hold the process to 2760 * prevent it being ripped out from under us either in the 2761 * file descriptor loop or in the greater LIST_FOREACH. The 2762 * process may be in varying states of disrepair. If the process 2763 * is in SZOMB we may have caught it just as it is being removed 2764 * from the allproc list, we must skip it in that case to maintain 2765 * an unbroken chain through the allproc list. 2766 */ 2767 info.count = 0; 2768 info.error = 0; 2769 info.req = req; 2770 allproc_scan(sysctl_kern_file_callback, &info); 2771 2772 /* 2773 * When just calculating the size, overestimate a bit to try to 2774 * prevent system activity from causing the buffer-fill call 2775 * to fail later on. 2776 */ 2777 if (req->oldptr == NULL) { 2778 info.count = (info.count + 16) + (info.count / 10); 2779 info.error = SYSCTL_OUT(req, NULL, 2780 info.count * sizeof(struct kinfo_file)); 2781 } 2782 return (info.error); 2783 } 2784 2785 static int 2786 sysctl_kern_file_callback(struct proc *p, void *data) 2787 { 2788 struct sysctl_kern_file_info *info = data; 2789 struct kinfo_file kf; 2790 struct filedesc *fdp; 2791 struct file *fp; 2792 uid_t uid; 2793 int n; 2794 2795 if (p->p_stat == SIDL || p->p_stat == SZOMB) 2796 return(0); 2797 if (!PRISON_CHECK(info->req->td->td_ucred, p->p_ucred) != 0) 2798 return(0); 2799 2800 /* 2801 * Softref the fdp to prevent it from being destroyed 2802 */ 2803 spin_lock(&p->p_spin); 2804 if ((fdp = p->p_fd) == NULL) { 2805 spin_unlock(&p->p_spin); 2806 return(0); 2807 } 2808 atomic_add_int(&fdp->fd_softrefs, 1); 2809 spin_unlock(&p->p_spin); 2810 2811 /* 2812 * The fdp's own spinlock prevents the contents from being 2813 * modified. 2814 */ 2815 spin_lock_shared(&fdp->fd_spin); 2816 for (n = 0; n < fdp->fd_nfiles; ++n) { 2817 if ((fp = fdp->fd_files[n].fp) == NULL) 2818 continue; 2819 if (info->req->oldptr == NULL) { 2820 ++info->count; 2821 } else { 2822 uid = p->p_ucred ? p->p_ucred->cr_uid : -1; 2823 kcore_make_file(&kf, fp, p->p_pid, uid, n); 2824 spin_unlock_shared(&fdp->fd_spin); 2825 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); 2826 spin_lock_shared(&fdp->fd_spin); 2827 if (info->error) 2828 break; 2829 } 2830 } 2831 spin_unlock_shared(&fdp->fd_spin); 2832 atomic_subtract_int(&fdp->fd_softrefs, 1); 2833 if (info->error) 2834 return(-1); 2835 return(0); 2836 } 2837 2838 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2839 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 2840 2841 SYSCTL_INT(_kern, OID_AUTO, minfilesperproc, CTLFLAG_RW, 2842 &minfilesperproc, 0, "Minimum files allowed open per process"); 2843 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2844 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2845 SYSCTL_INT(_kern, OID_AUTO, maxfilesperuser, CTLFLAG_RW, 2846 &maxfilesperuser, 0, "Maximum files allowed open per user"); 2847 2848 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2849 &maxfiles, 0, "Maximum number of files"); 2850 2851 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 2852 &maxfilesrootres, 0, "Descriptors reserved for root use"); 2853 2854 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2855 &nfiles, 0, "System-wide number of open files"); 2856 2857 static void 2858 fildesc_drvinit(void *unused) 2859 { 2860 int fd; 2861 2862 for (fd = 0; fd < NUMFDESC; fd++) { 2863 make_dev(&fildesc_ops, fd, 2864 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 2865 } 2866 2867 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 2868 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 2869 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 2870 } 2871 2872 /* 2873 * MPSAFE 2874 */ 2875 struct fileops badfileops = { 2876 .fo_read = badfo_readwrite, 2877 .fo_write = badfo_readwrite, 2878 .fo_ioctl = badfo_ioctl, 2879 .fo_kqfilter = badfo_kqfilter, 2880 .fo_stat = badfo_stat, 2881 .fo_close = badfo_close, 2882 .fo_shutdown = badfo_shutdown 2883 }; 2884 2885 int 2886 badfo_readwrite( 2887 struct file *fp, 2888 struct uio *uio, 2889 struct ucred *cred, 2890 int flags 2891 ) { 2892 return (EBADF); 2893 } 2894 2895 int 2896 badfo_ioctl(struct file *fp, u_long com, caddr_t data, 2897 struct ucred *cred, struct sysmsg *msgv) 2898 { 2899 return (EBADF); 2900 } 2901 2902 /* 2903 * Must return an error to prevent registration, typically 2904 * due to a revoked descriptor (file_filtops assigned). 2905 */ 2906 int 2907 badfo_kqfilter(struct file *fp, struct knote *kn) 2908 { 2909 return (EOPNOTSUPP); 2910 } 2911 2912 /* 2913 * MPSAFE 2914 */ 2915 int 2916 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) 2917 { 2918 return (EBADF); 2919 } 2920 2921 /* 2922 * MPSAFE 2923 */ 2924 int 2925 badfo_close(struct file *fp) 2926 { 2927 return (EBADF); 2928 } 2929 2930 /* 2931 * MPSAFE 2932 */ 2933 int 2934 badfo_shutdown(struct file *fp, int how) 2935 { 2936 return (EBADF); 2937 } 2938 2939 /* 2940 * MPSAFE 2941 */ 2942 int 2943 nofo_shutdown(struct file *fp, int how) 2944 { 2945 return (EOPNOTSUPP); 2946 } 2947 2948 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2949 fildesc_drvinit,NULL) 2950