| 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. All advertising materials mentioning features or use of this software |
| 52 | * must display the following acknowledgement: |
| 53 | * This product includes software developed by the University of |
| 54 | * California, Berkeley and its contributors. |
| 55 | * 4. Neither the name of the University nor the names of its contributors |
| 56 | * may be used to endorse or promote products derived from this software |
| 57 | * without specific prior written permission. |
| 58 | * |
| 59 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 60 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 61 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 62 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 63 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 64 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 65 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 66 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 67 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 68 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 69 | * SUCH DAMAGE. |
| 70 | * |
| 71 | * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 |
| 72 | * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $ |
| 73 | * $DragonFly: src/sys/kern/kern_descrip.c,v 1.79 2008/08/31 13:18:28 aggelos Exp $ |
| 74 | */ |
| 75 | |
| 76 | #include "opt_compat.h" |
| 77 | #include <sys/param.h> |
| 78 | #include <sys/systm.h> |
| 79 | #include <sys/malloc.h> |
| 80 | #include <sys/sysproto.h> |
| 81 | #include <sys/conf.h> |
| 82 | #include <sys/device.h> |
| 83 | #include <sys/filedesc.h> |
| 84 | #include <sys/kernel.h> |
| 85 | #include <sys/sysctl.h> |
| 86 | #include <sys/vnode.h> |
| 87 | #include <sys/proc.h> |
| 88 | #include <sys/nlookup.h> |
| 89 | #include <sys/file.h> |
| 90 | #include <sys/stat.h> |
| 91 | #include <sys/filio.h> |
| 92 | #include <sys/fcntl.h> |
| 93 | #include <sys/unistd.h> |
| 94 | #include <sys/resourcevar.h> |
| 95 | #include <sys/event.h> |
| 96 | #include <sys/kern_syscall.h> |
| 97 | #include <sys/kcore.h> |
| 98 | #include <sys/kinfo.h> |
| 99 | #include <sys/un.h> |
| 100 | |
| 101 | #include <vm/vm.h> |
| 102 | #include <vm/vm_extern.h> |
| 103 | |
| 104 | #include <sys/thread2.h> |
| 105 | #include <sys/file2.h> |
| 106 | #include <sys/spinlock2.h> |
| 107 | |
| 108 | static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd); |
| 109 | static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr); |
| 110 | static struct file *funsetfd_locked (struct filedesc *fdp, int fd); |
| 111 | static int checkfpclosed(struct filedesc *fdp, int fd, struct file *fp); |
| 112 | static void ffree(struct file *fp); |
| 113 | |
| 114 | static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); |
| 115 | static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", |
| 116 | "file desc to leader structures"); |
| 117 | MALLOC_DEFINE(M_FILE, "file", "Open file structure"); |
| 118 | static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); |
| 119 | |
| 120 | static d_open_t fdopen; |
| 121 | #define NUMFDESC 64 |
| 122 | |
| 123 | #define CDEV_MAJOR 22 |
| 124 | static struct dev_ops fildesc_ops = { |
| 125 | { "FD", CDEV_MAJOR, 0 }, |
| 126 | .d_open = fdopen, |
| 127 | }; |
| 128 | |
| 129 | static int badfo_readwrite (struct file *fp, struct uio *uio, |
| 130 | struct ucred *cred, int flags); |
| 131 | static int badfo_ioctl (struct file *fp, u_long com, caddr_t data, |
| 132 | struct ucred *cred); |
| 133 | static int badfo_poll (struct file *fp, int events, struct ucred *cred); |
| 134 | static int badfo_kqfilter (struct file *fp, struct knote *kn); |
| 135 | static int badfo_stat (struct file *fp, struct stat *sb, struct ucred *cred); |
| 136 | static int badfo_close (struct file *fp); |
| 137 | static int badfo_shutdown (struct file *fp, int how); |
| 138 | |
| 139 | /* |
| 140 | * Descriptor management. |
| 141 | */ |
| 142 | static struct filelist filehead = LIST_HEAD_INITIALIZER(&filehead); |
| 143 | static struct spinlock filehead_spin = SPINLOCK_INITIALIZER(&filehead_spin); |
| 144 | static int nfiles; /* actual number of open files */ |
| 145 | extern int cmask; |
| 146 | |
| 147 | /* |
| 148 | * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared. |
| 149 | * |
| 150 | * MPSAFE - must be called with fdp->fd_spin exclusively held |
| 151 | */ |
| 152 | static __inline |
| 153 | void |
| 154 | fdfixup_locked(struct filedesc *fdp, int fd) |
| 155 | { |
| 156 | if (fd < fdp->fd_freefile) { |
| 157 | fdp->fd_freefile = fd; |
| 158 | } |
| 159 | while (fdp->fd_lastfile >= 0 && |
| 160 | fdp->fd_files[fdp->fd_lastfile].fp == NULL && |
| 161 | fdp->fd_files[fdp->fd_lastfile].reserved == 0 |
| 162 | ) { |
| 163 | --fdp->fd_lastfile; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * System calls on descriptors. |
| 169 | * |
| 170 | * MPSAFE |
| 171 | */ |
| 172 | int |
| 173 | sys_getdtablesize(struct getdtablesize_args *uap) |
| 174 | { |
| 175 | struct proc *p = curproc; |
| 176 | struct plimit *limit = p->p_limit; |
| 177 | |
| 178 | spin_lock_rd(&limit->p_spin); |
| 179 | uap->sysmsg_result = |
| 180 | min((int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); |
| 181 | spin_unlock_rd(&limit->p_spin); |
| 182 | return (0); |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * Duplicate a file descriptor to a particular value. |
| 187 | * |
| 188 | * note: keep in mind that a potential race condition exists when closing |
| 189 | * descriptors from a shared descriptor table (via rfork). |
| 190 | * |
| 191 | * MPSAFE |
| 192 | */ |
| 193 | int |
| 194 | sys_dup2(struct dup2_args *uap) |
| 195 | { |
| 196 | int error; |
| 197 | |
| 198 | error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds); |
| 199 | |
| 200 | return (error); |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Duplicate a file descriptor. |
| 205 | * |
| 206 | * MPSAFE |
| 207 | */ |
| 208 | int |
| 209 | sys_dup(struct dup_args *uap) |
| 210 | { |
| 211 | int error; |
| 212 | |
| 213 | error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds); |
| 214 | |
| 215 | return (error); |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * MPALMOSTSAFE - acquires mplock for fp operations |
| 220 | */ |
| 221 | int |
| 222 | kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred) |
| 223 | { |
| 224 | struct thread *td = curthread; |
| 225 | struct proc *p = td->td_proc; |
| 226 | struct file *fp; |
| 227 | struct vnode *vp; |
| 228 | u_int newmin; |
| 229 | u_int oflags; |
| 230 | u_int nflags; |
| 231 | int tmp, error, flg = F_POSIX; |
| 232 | |
| 233 | KKASSERT(p); |
| 234 | |
| 235 | /* |
| 236 | * Operations on file descriptors that do not require a file pointer. |
| 237 | */ |
| 238 | switch (cmd) { |
| 239 | case F_GETFD: |
| 240 | error = fgetfdflags(p->p_fd, fd, &tmp); |
| 241 | if (error == 0) |
| 242 | dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0; |
| 243 | return (error); |
| 244 | |
| 245 | case F_SETFD: |
| 246 | if (dat->fc_cloexec & FD_CLOEXEC) |
| 247 | error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE); |
| 248 | else |
| 249 | error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE); |
| 250 | return (error); |
| 251 | case F_DUPFD: |
| 252 | newmin = dat->fc_fd; |
| 253 | error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd); |
| 254 | return (error); |
| 255 | default: |
| 256 | break; |
| 257 | } |
| 258 | |
| 259 | /* |
| 260 | * Operations on file pointers |
| 261 | */ |
| 262 | if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) |
| 263 | return (EBADF); |
| 264 | |
| 265 | get_mplock(); |
| 266 | switch (cmd) { |
| 267 | case F_GETFL: |
| 268 | dat->fc_flags = OFLAGS(fp->f_flag); |
| 269 | error = 0; |
| 270 | break; |
| 271 | |
| 272 | case F_SETFL: |
| 273 | oflags = fp->f_flag; |
| 274 | nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; |
| 275 | nflags |= oflags & ~FCNTLFLAGS; |
| 276 | |
| 277 | error = 0; |
| 278 | if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) |
| 279 | error = EINVAL; |
| 280 | if (error == 0 && ((nflags ^ oflags) & FASYNC)) { |
| 281 | tmp = fp->f_flag & FASYNC; |
| 282 | error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, cred); |
| 283 | } |
| 284 | if (error == 0) |
| 285 | fp->f_flag = nflags; |
| 286 | break; |
| 287 | |
| 288 | case F_GETOWN: |
| 289 | error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, cred); |
| 290 | break; |
| 291 | |
| 292 | case F_SETOWN: |
| 293 | error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, cred); |
| 294 | break; |
| 295 | |
| 296 | case F_SETLKW: |
| 297 | flg |= F_WAIT; |
| 298 | /* Fall into F_SETLK */ |
| 299 | |
| 300 | case F_SETLK: |
| 301 | if (fp->f_type != DTYPE_VNODE) { |
| 302 | error = EBADF; |
| 303 | break; |
| 304 | } |
| 305 | vp = (struct vnode *)fp->f_data; |
| 306 | |
| 307 | /* |
| 308 | * copyin/lockop may block |
| 309 | */ |
| 310 | if (dat->fc_flock.l_whence == SEEK_CUR) |
| 311 | dat->fc_flock.l_start += fp->f_offset; |
| 312 | |
| 313 | switch (dat->fc_flock.l_type) { |
| 314 | case F_RDLCK: |
| 315 | if ((fp->f_flag & FREAD) == 0) { |
| 316 | error = EBADF; |
| 317 | break; |
| 318 | } |
| 319 | p->p_leader->p_flag |= P_ADVLOCK; |
| 320 | error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, |
| 321 | &dat->fc_flock, flg); |
| 322 | break; |
| 323 | case F_WRLCK: |
| 324 | if ((fp->f_flag & FWRITE) == 0) { |
| 325 | error = EBADF; |
| 326 | break; |
| 327 | } |
| 328 | p->p_leader->p_flag |= P_ADVLOCK; |
| 329 | error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, |
| 330 | &dat->fc_flock, flg); |
| 331 | break; |
| 332 | case F_UNLCK: |
| 333 | error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, |
| 334 | &dat->fc_flock, F_POSIX); |
| 335 | break; |
| 336 | default: |
| 337 | error = EINVAL; |
| 338 | break; |
| 339 | } |
| 340 | |
| 341 | /* |
| 342 | * It is possible to race a close() on the descriptor while |
| 343 | * we were blocked getting the lock. If this occurs the |
| 344 | * close might not have caught the lock. |
| 345 | */ |
| 346 | if (checkfpclosed(p->p_fd, fd, fp)) { |
| 347 | dat->fc_flock.l_whence = SEEK_SET; |
| 348 | dat->fc_flock.l_start = 0; |
| 349 | dat->fc_flock.l_len = 0; |
| 350 | dat->fc_flock.l_type = F_UNLCK; |
| 351 | (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, |
| 352 | F_UNLCK, &dat->fc_flock, F_POSIX); |
| 353 | } |
| 354 | break; |
| 355 | |
| 356 | case F_GETLK: |
| 357 | if (fp->f_type != DTYPE_VNODE) { |
| 358 | error = EBADF; |
| 359 | break; |
| 360 | } |
| 361 | vp = (struct vnode *)fp->f_data; |
| 362 | /* |
| 363 | * copyin/lockop may block |
| 364 | */ |
| 365 | if (dat->fc_flock.l_type != F_RDLCK && |
| 366 | dat->fc_flock.l_type != F_WRLCK && |
| 367 | dat->fc_flock.l_type != F_UNLCK) { |
| 368 | error = EINVAL; |
| 369 | break; |
| 370 | } |
| 371 | if (dat->fc_flock.l_whence == SEEK_CUR) |
| 372 | dat->fc_flock.l_start += fp->f_offset; |
| 373 | error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, |
| 374 | &dat->fc_flock, F_POSIX); |
| 375 | break; |
| 376 | default: |
| 377 | error = EINVAL; |
| 378 | break; |
| 379 | } |
| 380 | rel_mplock(); |
| 381 | |
| 382 | fdrop(fp); |
| 383 | return (error); |
| 384 | } |
| 385 | |
| 386 | /* |
| 387 | * The file control system call. |
| 388 | * |
| 389 | * MPSAFE |
| 390 | */ |
| 391 | int |
| 392 | sys_fcntl(struct fcntl_args *uap) |
| 393 | { |
| 394 | union fcntl_dat dat; |
| 395 | int error; |
| 396 | |
| 397 | switch (uap->cmd) { |
| 398 | case F_DUPFD: |
| 399 | dat.fc_fd = uap->arg; |
| 400 | break; |
| 401 | case F_SETFD: |
| 402 | dat.fc_cloexec = uap->arg; |
| 403 | break; |
| 404 | case F_SETFL: |
| 405 | dat.fc_flags = uap->arg; |
| 406 | break; |
| 407 | case F_SETOWN: |
| 408 | dat.fc_owner = uap->arg; |
| 409 | break; |
| 410 | case F_SETLKW: |
| 411 | case F_SETLK: |
| 412 | case F_GETLK: |
| 413 | error = copyin((caddr_t)uap->arg, &dat.fc_flock, |
| 414 | sizeof(struct flock)); |
| 415 | if (error) |
| 416 | return (error); |
| 417 | break; |
| 418 | } |
| 419 | |
| 420 | error = kern_fcntl(uap->fd, uap->cmd, &dat, curproc->p_ucred); |
| 421 | |
| 422 | if (error == 0) { |
| 423 | switch (uap->cmd) { |
| 424 | case F_DUPFD: |
| 425 | uap->sysmsg_result = dat.fc_fd; |
| 426 | break; |
| 427 | case F_GETFD: |
| 428 | uap->sysmsg_result = dat.fc_cloexec; |
| 429 | break; |
| 430 | case F_GETFL: |
| 431 | uap->sysmsg_result = dat.fc_flags; |
| 432 | break; |
| 433 | case F_GETOWN: |
| 434 | uap->sysmsg_result = dat.fc_owner; |
| 435 | case F_GETLK: |
| 436 | error = copyout(&dat.fc_flock, (caddr_t)uap->arg, |
| 437 | sizeof(struct flock)); |
| 438 | break; |
| 439 | } |
| 440 | } |
| 441 | |
| 442 | return (error); |
| 443 | } |
| 444 | |
| 445 | /* |
| 446 | * Common code for dup, dup2, and fcntl(F_DUPFD). |
| 447 | * |
| 448 | * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells |
| 449 | * kern_dup() to destructively dup over an existing file descriptor if new |
| 450 | * is already open. DUP_VARIABLE tells kern_dup() to find the lowest |
| 451 | * unused file descriptor that is greater than or equal to new. |
| 452 | * |
| 453 | * MPSAFE |
| 454 | */ |
| 455 | int |
| 456 | kern_dup(enum dup_type type, int old, int new, int *res) |
| 457 | { |
| 458 | struct thread *td = curthread; |
| 459 | struct proc *p = td->td_proc; |
| 460 | struct filedesc *fdp = p->p_fd; |
| 461 | struct file *fp; |
| 462 | struct file *delfp; |
| 463 | int oldflags; |
| 464 | int holdleaders; |
| 465 | int error, newfd; |
| 466 | |
| 467 | /* |
| 468 | * Verify that we have a valid descriptor to dup from and |
| 469 | * possibly to dup to. |
| 470 | */ |
| 471 | retry: |
| 472 | spin_lock_wr(&fdp->fd_spin); |
| 473 | if (new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur || |
| 474 | new >= maxfilesperproc) { |
| 475 | spin_unlock_wr(&fdp->fd_spin); |
| 476 | return (EINVAL); |
| 477 | } |
| 478 | if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { |
| 479 | spin_unlock_wr(&fdp->fd_spin); |
| 480 | return (EBADF); |
| 481 | } |
| 482 | if (type == DUP_FIXED && old == new) { |
| 483 | *res = new; |
| 484 | spin_unlock_wr(&fdp->fd_spin); |
| 485 | return (0); |
| 486 | } |
| 487 | fp = fdp->fd_files[old].fp; |
| 488 | oldflags = fdp->fd_files[old].fileflags; |
| 489 | fhold(fp); /* MPSAFE - can be called with a spinlock held */ |
| 490 | |
| 491 | /* |
| 492 | * Allocate a new descriptor if DUP_VARIABLE, or expand the table |
| 493 | * if the requested descriptor is beyond the current table size. |
| 494 | * |
| 495 | * This can block. Retry if the source descriptor no longer matches |
| 496 | * or if our expectation in the expansion case races. |
| 497 | * |
| 498 | * If we are not expanding or allocating a new decriptor, then reset |
| 499 | * the target descriptor to a reserved state so we have a uniform |
| 500 | * setup for the next code block. |
| 501 | */ |
| 502 | if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) { |
| 503 | spin_unlock_wr(&fdp->fd_spin); |
| 504 | error = fdalloc(p, new, &newfd); |
| 505 | spin_lock_wr(&fdp->fd_spin); |
| 506 | if (error) { |
| 507 | spin_unlock_wr(&fdp->fd_spin); |
| 508 | fdrop(fp); |
| 509 | return (error); |
| 510 | } |
| 511 | /* |
| 512 | * Check for ripout |
| 513 | */ |
| 514 | if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { |
| 515 | fsetfd_locked(fdp, NULL, newfd); |
| 516 | spin_unlock_wr(&fdp->fd_spin); |
| 517 | fdrop(fp); |
| 518 | goto retry; |
| 519 | } |
| 520 | /* |
| 521 | * Check for expansion race |
| 522 | */ |
| 523 | if (type != DUP_VARIABLE && new != newfd) { |
| 524 | fsetfd_locked(fdp, NULL, newfd); |
| 525 | spin_unlock_wr(&fdp->fd_spin); |
| 526 | fdrop(fp); |
| 527 | goto retry; |
| 528 | } |
| 529 | /* |
| 530 | * Check for ripout, newfd reused old (this case probably |
| 531 | * can't occur). |
| 532 | */ |
| 533 | if (old == newfd) { |
| 534 | fsetfd_locked(fdp, NULL, newfd); |
| 535 | spin_unlock_wr(&fdp->fd_spin); |
| 536 | fdrop(fp); |
| 537 | goto retry; |
| 538 | } |
| 539 | new = newfd; |
| 540 | delfp = NULL; |
| 541 | } else { |
| 542 | if (fdp->fd_files[new].reserved) { |
| 543 | spin_unlock_wr(&fdp->fd_spin); |
| 544 | fdrop(fp); |
| 545 | kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new); |
| 546 | tsleep(fdp, 0, "fdres", hz); |
| 547 | goto retry; |
| 548 | } |
| 549 | |
| 550 | /* |
| 551 | * If the target descriptor was never allocated we have |
| 552 | * to allocate it. If it was we have to clean out the |
| 553 | * old descriptor. delfp inherits the ref from the |
| 554 | * descriptor table. |
| 555 | */ |
| 556 | delfp = fdp->fd_files[new].fp; |
| 557 | fdp->fd_files[new].fp = NULL; |
| 558 | fdp->fd_files[new].reserved = 1; |
| 559 | if (delfp == NULL) { |
| 560 | fdreserve_locked(fdp, new, 1); |
| 561 | if (new > fdp->fd_lastfile) |
| 562 | fdp->fd_lastfile = new; |
| 563 | } |
| 564 | |
| 565 | } |
| 566 | |
| 567 | /* |
| 568 | * NOTE: still holding an exclusive spinlock |
| 569 | */ |
| 570 | |
| 571 | /* |
| 572 | * If a descriptor is being overwritten we may hve to tell |
| 573 | * fdfree() to sleep to ensure that all relevant process |
| 574 | * leaders can be traversed in closef(). |
| 575 | */ |
| 576 | if (delfp != NULL && p->p_fdtol != NULL) { |
| 577 | fdp->fd_holdleaderscount++; |
| 578 | holdleaders = 1; |
| 579 | } else { |
| 580 | holdleaders = 0; |
| 581 | } |
| 582 | KASSERT(delfp == NULL || type == DUP_FIXED, |
| 583 | ("dup() picked an open file")); |
| 584 | |
| 585 | /* |
| 586 | * Duplicate the source descriptor, update lastfile. If the new |
| 587 | * descriptor was not allocated and we aren't replacing an existing |
| 588 | * descriptor we have to mark the descriptor as being in use. |
| 589 | * |
| 590 | * The fd_files[] array inherits fp's hold reference. |
| 591 | */ |
| 592 | fsetfd_locked(fdp, fp, new); |
| 593 | fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; |
| 594 | spin_unlock_wr(&fdp->fd_spin); |
| 595 | fdrop(fp); |
| 596 | *res = new; |
| 597 | |
| 598 | /* |
| 599 | * If we dup'd over a valid file, we now own the reference to it |
| 600 | * and must dispose of it using closef() semantics (as if a |
| 601 | * close() were performed on it). |
| 602 | */ |
| 603 | if (delfp) { |
| 604 | closef(delfp, p); |
| 605 | if (holdleaders) { |
| 606 | spin_lock_wr(&fdp->fd_spin); |
| 607 | fdp->fd_holdleaderscount--; |
| 608 | if (fdp->fd_holdleaderscount == 0 && |
| 609 | fdp->fd_holdleaderswakeup != 0) { |
| 610 | fdp->fd_holdleaderswakeup = 0; |
| 611 | spin_unlock_wr(&fdp->fd_spin); |
| 612 | wakeup(&fdp->fd_holdleaderscount); |
| 613 | } else { |
| 614 | spin_unlock_wr(&fdp->fd_spin); |
| 615 | } |
| 616 | } |
| 617 | } |
| 618 | return (0); |
| 619 | } |
| 620 | |
| 621 | /* |
| 622 | * If sigio is on the list associated with a process or process group, |
| 623 | * disable signalling from the device, remove sigio from the list and |
| 624 | * free sigio. |
| 625 | */ |
| 626 | void |
| 627 | funsetown(struct sigio *sigio) |
| 628 | { |
| 629 | if (sigio == NULL) |
| 630 | return; |
| 631 | crit_enter(); |
| 632 | *(sigio->sio_myref) = NULL; |
| 633 | crit_exit(); |
| 634 | if (sigio->sio_pgid < 0) { |
| 635 | SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, |
| 636 | sigio, sio_pgsigio); |
| 637 | } else /* if ((*sigiop)->sio_pgid > 0) */ { |
| 638 | SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, |
| 639 | sigio, sio_pgsigio); |
| 640 | } |
| 641 | crfree(sigio->sio_ucred); |
| 642 | kfree(sigio, M_SIGIO); |
| 643 | } |
| 644 | |
| 645 | /* Free a list of sigio structures. */ |
| 646 | void |
| 647 | funsetownlst(struct sigiolst *sigiolst) |
| 648 | { |
| 649 | struct sigio *sigio; |
| 650 | |
| 651 | while ((sigio = SLIST_FIRST(sigiolst)) != NULL) |
| 652 | funsetown(sigio); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). |
| 657 | * |
| 658 | * After permission checking, add a sigio structure to the sigio list for |
| 659 | * the process or process group. |
| 660 | */ |
| 661 | int |
| 662 | fsetown(pid_t pgid, struct sigio **sigiop) |
| 663 | { |
| 664 | struct proc *proc; |
| 665 | struct pgrp *pgrp; |
| 666 | struct sigio *sigio; |
| 667 | |
| 668 | if (pgid == 0) { |
| 669 | funsetown(*sigiop); |
| 670 | return (0); |
| 671 | } |
| 672 | if (pgid > 0) { |
| 673 | proc = pfind(pgid); |
| 674 | if (proc == NULL) |
| 675 | return (ESRCH); |
| 676 | |
| 677 | /* |
| 678 | * Policy - Don't allow a process to FSETOWN a process |
| 679 | * in another session. |
| 680 | * |
| 681 | * Remove this test to allow maximum flexibility or |
| 682 | * restrict FSETOWN to the current process or process |
| 683 | * group for maximum safety. |
| 684 | */ |
| 685 | if (proc->p_session != curproc->p_session) |
| 686 | return (EPERM); |
| 687 | |
| 688 | pgrp = NULL; |
| 689 | } else /* if (pgid < 0) */ { |
| 690 | pgrp = pgfind(-pgid); |
| 691 | if (pgrp == NULL) |
| 692 | return (ESRCH); |
| 693 | |
| 694 | /* |
| 695 | * Policy - Don't allow a process to FSETOWN a process |
| 696 | * in another session. |
| 697 | * |
| 698 | * Remove this test to allow maximum flexibility or |
| 699 | * restrict FSETOWN to the current process or process |
| 700 | * group for maximum safety. |
| 701 | */ |
| 702 | if (pgrp->pg_session != curproc->p_session) |
| 703 | return (EPERM); |
| 704 | |
| 705 | proc = NULL; |
| 706 | } |
| 707 | funsetown(*sigiop); |
| 708 | sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); |
| 709 | if (pgid > 0) { |
| 710 | SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); |
| 711 | sigio->sio_proc = proc; |
| 712 | } else { |
| 713 | SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); |
| 714 | sigio->sio_pgrp = pgrp; |
| 715 | } |
| 716 | sigio->sio_pgid = pgid; |
| 717 | sigio->sio_ucred = crhold(curproc->p_ucred); |
| 718 | /* It would be convenient if p_ruid was in ucred. */ |
| 719 | sigio->sio_ruid = curproc->p_ucred->cr_ruid; |
| 720 | sigio->sio_myref = sigiop; |
| 721 | crit_enter(); |
| 722 | *sigiop = sigio; |
| 723 | crit_exit(); |
| 724 | return (0); |
| 725 | } |
| 726 | |
| 727 | /* |
| 728 | * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). |
| 729 | */ |
| 730 | pid_t |
| 731 | fgetown(struct sigio *sigio) |
| 732 | { |
| 733 | return (sigio != NULL ? sigio->sio_pgid : 0); |
| 734 | } |
| 735 | |
| 736 | /* |
| 737 | * Close many file descriptors. |
| 738 | * |
| 739 | * MPSAFE |
| 740 | */ |
| 741 | int |
| 742 | sys_closefrom(struct closefrom_args *uap) |
| 743 | { |
| 744 | return(kern_closefrom(uap->fd)); |
| 745 | } |
| 746 | |
| 747 | /* |
| 748 | * Close all file descriptors greater then or equal to fd |
| 749 | * |
| 750 | * MPSAFE |
| 751 | */ |
| 752 | int |
| 753 | kern_closefrom(int fd) |
| 754 | { |
| 755 | struct thread *td = curthread; |
| 756 | struct proc *p = td->td_proc; |
| 757 | struct filedesc *fdp; |
| 758 | |
| 759 | KKASSERT(p); |
| 760 | fdp = p->p_fd; |
| 761 | |
| 762 | if (fd < 0) |
| 763 | return (EINVAL); |
| 764 | |
| 765 | /* |
| 766 | * NOTE: This function will skip unassociated descriptors and |
| 767 | * reserved descriptors that have not yet been assigned. |
| 768 | * fd_lastfile can change as a side effect of kern_close(). |
| 769 | */ |
| 770 | spin_lock_wr(&fdp->fd_spin); |
| 771 | while (fd <= fdp->fd_lastfile) { |
| 772 | if (fdp->fd_files[fd].fp != NULL) { |
| 773 | spin_unlock_wr(&fdp->fd_spin); |
| 774 | /* ok if this races another close */ |
| 775 | if (kern_close(fd) == EINTR) |
| 776 | return (EINTR); |
| 777 | spin_lock_wr(&fdp->fd_spin); |
| 778 | } |
| 779 | ++fd; |
| 780 | } |
| 781 | spin_unlock_wr(&fdp->fd_spin); |
| 782 | return (0); |
| 783 | } |
| 784 | |
| 785 | /* |
| 786 | * Close a file descriptor. |
| 787 | * |
| 788 | * MPSAFE |
| 789 | */ |
| 790 | int |
| 791 | sys_close(struct close_args *uap) |
| 792 | { |
| 793 | return(kern_close(uap->fd)); |
| 794 | } |
| 795 | |
| 796 | /* |
| 797 | * MPALMOSTSAFE - acquires mplock around knote_fdclose() calls |
| 798 | */ |
| 799 | int |
| 800 | kern_close(int fd) |
| 801 | { |
| 802 | struct thread *td = curthread; |
| 803 | struct proc *p = td->td_proc; |
| 804 | struct filedesc *fdp; |
| 805 | struct file *fp; |
| 806 | int error; |
| 807 | int holdleaders; |
| 808 | |
| 809 | KKASSERT(p); |
| 810 | fdp = p->p_fd; |
| 811 | |
| 812 | spin_lock_wr(&fdp->fd_spin); |
| 813 | if ((fp = funsetfd_locked(fdp, fd)) == NULL) { |
| 814 | spin_unlock_wr(&fdp->fd_spin); |
| 815 | return (EBADF); |
| 816 | } |
| 817 | holdleaders = 0; |
| 818 | if (p->p_fdtol != NULL) { |
| 819 | /* |
| 820 | * Ask fdfree() to sleep to ensure that all relevant |
| 821 | * process leaders can be traversed in closef(). |
| 822 | */ |
| 823 | fdp->fd_holdleaderscount++; |
| 824 | holdleaders = 1; |
| 825 | } |
| 826 | |
| 827 | /* |
| 828 | * we now hold the fp reference that used to be owned by the descriptor |
| 829 | * array. |
| 830 | */ |
| 831 | spin_unlock_wr(&fdp->fd_spin); |
| 832 | if (fd < fdp->fd_knlistsize) { |
| 833 | get_mplock(); |
| 834 | if (fd < fdp->fd_knlistsize) |
| 835 | knote_fdclose(p, fd); |
| 836 | rel_mplock(); |
| 837 | } |
| 838 | error = closef(fp, p); |
| 839 | if (holdleaders) { |
| 840 | spin_lock_wr(&fdp->fd_spin); |
| 841 | fdp->fd_holdleaderscount--; |
| 842 | if (fdp->fd_holdleaderscount == 0 && |
| 843 | fdp->fd_holdleaderswakeup != 0) { |
| 844 | fdp->fd_holdleaderswakeup = 0; |
| 845 | spin_unlock_wr(&fdp->fd_spin); |
| 846 | wakeup(&fdp->fd_holdleaderscount); |
| 847 | } else { |
| 848 | spin_unlock_wr(&fdp->fd_spin); |
| 849 | } |
| 850 | } |
| 851 | return (error); |
| 852 | } |
| 853 | |
| 854 | /* |
| 855 | * shutdown_args(int fd, int how) |
| 856 | */ |
| 857 | int |
| 858 | kern_shutdown(int fd, int how) |
| 859 | { |
| 860 | struct thread *td = curthread; |
| 861 | struct proc *p = td->td_proc; |
| 862 | struct file *fp; |
| 863 | int error; |
| 864 | |
| 865 | KKASSERT(p); |
| 866 | |
| 867 | if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) |
| 868 | return (EBADF); |
| 869 | error = fo_shutdown(fp, how); |
| 870 | fdrop(fp); |
| 871 | |
| 872 | return (error); |
| 873 | } |
| 874 | |
| 875 | int |
| 876 | sys_shutdown(struct shutdown_args *uap) |
| 877 | { |
| 878 | int error; |
| 879 | |
| 880 | error = kern_shutdown(uap->s, uap->how); |
| 881 | |
| 882 | return (error); |
| 883 | } |
| 884 | |
| 885 | int |
| 886 | kern_fstat(int fd, struct stat *ub) |
| 887 | { |
| 888 | struct thread *td = curthread; |
| 889 | struct proc *p = td->td_proc; |
| 890 | struct file *fp; |
| 891 | int error; |
| 892 | |
| 893 | KKASSERT(p); |
| 894 | |
| 895 | if ((fp = holdfp(p->p_fd, fd, -1)) == NULL) |
| 896 | return (EBADF); |
| 897 | error = fo_stat(fp, ub, p->p_ucred); |
| 898 | fdrop(fp); |
| 899 | |
| 900 | return (error); |
| 901 | } |
| 902 | |
| 903 | /* |
| 904 | * Return status information about a file descriptor. |
| 905 | */ |
| 906 | int |
| 907 | sys_fstat(struct fstat_args *uap) |
| 908 | { |
| 909 | struct stat st; |
| 910 | int error; |
| 911 | |
| 912 | error = kern_fstat(uap->fd, &st); |
| 913 | |
| 914 | if (error == 0) |
| 915 | error = copyout(&st, uap->sb, sizeof(st)); |
| 916 | return (error); |
| 917 | } |
| 918 | |
| 919 | /* |
| 920 | * Return pathconf information about a file descriptor. |
| 921 | */ |
| 922 | /* ARGSUSED */ |
| 923 | int |
| 924 | sys_fpathconf(struct fpathconf_args *uap) |
| 925 | { |
| 926 | struct thread *td = curthread; |
| 927 | struct proc *p = td->td_proc; |
| 928 | struct file *fp; |
| 929 | struct vnode *vp; |
| 930 | int error = 0; |
| 931 | |
| 932 | KKASSERT(p); |
| 933 | |
| 934 | if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) |
| 935 | return (EBADF); |
| 936 | |
| 937 | switch (fp->f_type) { |
| 938 | case DTYPE_PIPE: |
| 939 | case DTYPE_SOCKET: |
| 940 | if (uap->name != _PC_PIPE_BUF) { |
| 941 | error = EINVAL; |
| 942 | } else { |
| 943 | uap->sysmsg_result = PIPE_BUF; |
| 944 | error = 0; |
| 945 | } |
| 946 | break; |
| 947 | case DTYPE_FIFO: |
| 948 | case DTYPE_VNODE: |
| 949 | vp = (struct vnode *)fp->f_data; |
| 950 | error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds); |
| 951 | break; |
| 952 | default: |
| 953 | error = EOPNOTSUPP; |
| 954 | break; |
| 955 | } |
| 956 | fdrop(fp); |
| 957 | return(error); |
| 958 | } |
| 959 | |
| 960 | static int fdexpand; |
| 961 | SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, ""); |
| 962 | |
| 963 | /* |
| 964 | * Grow the file table so it can hold through descriptor (want). |
| 965 | * |
| 966 | * The fdp's spinlock must be held exclusively on entry and may be held |
| 967 | * exclusively on return. The spinlock may be cycled by the routine. |
| 968 | * |
| 969 | * MPSAFE |
| 970 | */ |
| 971 | static void |
| 972 | fdgrow_locked(struct filedesc *fdp, int want) |
| 973 | { |
| 974 | struct fdnode *newfiles; |
| 975 | struct fdnode *oldfiles; |
| 976 | int nf, extra; |
| 977 | |
| 978 | nf = fdp->fd_nfiles; |
| 979 | do { |
| 980 | /* nf has to be of the form 2^n - 1 */ |
| 981 | nf = 2 * nf + 1; |
| 982 | } while (nf <= want); |
| 983 | |
| 984 | spin_unlock_wr(&fdp->fd_spin); |
| 985 | newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); |
| 986 | spin_lock_wr(&fdp->fd_spin); |
| 987 | |
| 988 | /* |
| 989 | * We could have raced another extend while we were not holding |
| 990 | * the spinlock. |
| 991 | */ |
| 992 | if (fdp->fd_nfiles >= nf) { |
| 993 | spin_unlock_wr(&fdp->fd_spin); |
| 994 | kfree(newfiles, M_FILEDESC); |
| 995 | spin_lock_wr(&fdp->fd_spin); |
| 996 | return; |
| 997 | } |
| 998 | /* |
| 999 | * Copy the existing ofile and ofileflags arrays |
| 1000 | * and zero the new portion of each array. |
| 1001 | */ |
| 1002 | extra = nf - fdp->fd_nfiles; |
| 1003 | bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); |
| 1004 | bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); |
| 1005 | |
| 1006 | oldfiles = fdp->fd_files; |
| 1007 | fdp->fd_files = newfiles; |
| 1008 | fdp->fd_nfiles = nf; |
| 1009 | |
| 1010 | if (oldfiles != fdp->fd_builtin_files) { |
| 1011 | spin_unlock_wr(&fdp->fd_spin); |
| 1012 | kfree(oldfiles, M_FILEDESC); |
| 1013 | spin_lock_wr(&fdp->fd_spin); |
| 1014 | } |
| 1015 | fdexpand++; |
| 1016 | } |
| 1017 | |
| 1018 | /* |
| 1019 | * Number of nodes in right subtree, including the root. |
| 1020 | */ |
| 1021 | static __inline int |
| 1022 | right_subtree_size(int n) |
| 1023 | { |
| 1024 | return (n ^ (n | (n + 1))); |
| 1025 | } |
| 1026 | |
| 1027 | /* |
| 1028 | * Bigger ancestor. |
| 1029 | */ |
| 1030 | static __inline int |
| 1031 | right_ancestor(int n) |
| 1032 | { |
| 1033 | return (n | (n + 1)); |
| 1034 | } |
| 1035 | |
| 1036 | /* |
| 1037 | * Smaller ancestor. |
| 1038 | */ |
| 1039 | static __inline int |
| 1040 | left_ancestor(int n) |
| 1041 | { |
| 1042 | return ((n & (n + 1)) - 1); |
| 1043 | } |
| 1044 | |
| 1045 | /* |
| 1046 | * Traverse the in-place binary tree buttom-up adjusting the allocation |
| 1047 | * count so scans can determine where free descriptors are located. |
| 1048 | * |
| 1049 | * MPSAFE - caller must be holding an exclusive spinlock on fdp |
| 1050 | */ |
| 1051 | static |
| 1052 | void |
| 1053 | fdreserve_locked(struct filedesc *fdp, int fd, int incr) |
| 1054 | { |
| 1055 | while (fd >= 0) { |
| 1056 | fdp->fd_files[fd].allocated += incr; |
| 1057 | KKASSERT(fdp->fd_files[fd].allocated >= 0); |
| 1058 | fd = left_ancestor(fd); |
| 1059 | } |
| 1060 | } |
| 1061 | |
| 1062 | /* |
| 1063 | * Reserve a file descriptor for the process. If no error occurs, the |
| 1064 | * caller MUST at some point call fsetfd() or assign a file pointer |
| 1065 | * or dispose of the reservation. |
| 1066 | * |
| 1067 | * MPSAFE |
| 1068 | */ |
| 1069 | int |
| 1070 | fdalloc(struct proc *p, int want, int *result) |
| 1071 | { |
| 1072 | struct filedesc *fdp = p->p_fd; |
| 1073 | int fd, rsize, rsum, node, lim; |
| 1074 | |
| 1075 | spin_lock_rd(&p->p_limit->p_spin); |
| 1076 | lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); |
| 1077 | spin_unlock_rd(&p->p_limit->p_spin); |
| 1078 | if (want >= lim) |
| 1079 | return (EMFILE); |
| 1080 | spin_lock_wr(&fdp->fd_spin); |
| 1081 | if (want >= fdp->fd_nfiles) |
| 1082 | fdgrow_locked(fdp, want); |
| 1083 | |
| 1084 | /* |
| 1085 | * Search for a free descriptor starting at the higher |
| 1086 | * of want or fd_freefile. If that fails, consider |
| 1087 | * expanding the ofile array. |
| 1088 | * |
| 1089 | * NOTE! the 'allocated' field is a cumulative recursive allocation |
| 1090 | * count. If we happen to see a value of 0 then we can shortcut |
| 1091 | * our search. Otherwise we run through through the tree going |
| 1092 | * down branches we know have free descriptor(s) until we hit a |
| 1093 | * leaf node. The leaf node will be free but will not necessarily |
| 1094 | * have an allocated field of 0. |
| 1095 | */ |
| 1096 | retry: |
| 1097 | /* move up the tree looking for a subtree with a free node */ |
| 1098 | for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); |
| 1099 | fd = right_ancestor(fd)) { |
| 1100 | if (fdp->fd_files[fd].allocated == 0) |
| 1101 | goto found; |
| 1102 | |
| 1103 | rsize = right_subtree_size(fd); |
| 1104 | if (fdp->fd_files[fd].allocated == rsize) |
| 1105 | continue; /* right subtree full */ |
| 1106 | |
| 1107 | /* |
| 1108 | * Free fd is in the right subtree of the tree rooted at fd. |
| 1109 | * Call that subtree R. Look for the smallest (leftmost) |
| 1110 | * subtree of R with an unallocated fd: continue moving |
| 1111 | * down the left branch until encountering a full left |
| 1112 | * subtree, then move to the right. |
| 1113 | */ |
| 1114 | for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { |
| 1115 | node = fd + rsize; |
| 1116 | rsum += fdp->fd_files[node].allocated; |
| 1117 | if (fdp->fd_files[fd].allocated == rsum + rsize) { |
| 1118 | fd = node; /* move to the right */ |
| 1119 | if (fdp->fd_files[node].allocated == 0) |
| 1120 | goto found; |
| 1121 | rsum = 0; |
| 1122 | } |
| 1123 | } |
| 1124 | goto found; |
| 1125 | } |
| 1126 | |
| 1127 | /* |
| 1128 | * No space in current array. Expand? |
| 1129 | */ |
| 1130 | if (fdp->fd_nfiles >= lim) { |
| 1131 | spin_unlock_wr(&fdp->fd_spin); |
| 1132 | return (EMFILE); |
| 1133 | } |
| 1134 | fdgrow_locked(fdp, want); |
| 1135 | goto retry; |
| 1136 | |
| 1137 | found: |
| 1138 | KKASSERT(fd < fdp->fd_nfiles); |
| 1139 | if (fd > fdp->fd_lastfile) |
| 1140 | fdp->fd_lastfile = fd; |
| 1141 | if (want <= fdp->fd_freefile) |
| 1142 | fdp->fd_freefile = fd; |
| 1143 | *result = fd; |
| 1144 | KKASSERT(fdp->fd_files[fd].fp == NULL); |
| 1145 | KKASSERT(fdp->fd_files[fd].reserved == 0); |
| 1146 | fdp->fd_files[fd].fileflags = 0; |
| 1147 | fdp->fd_files[fd].reserved = 1; |
| 1148 | fdreserve_locked(fdp, fd, 1); |
| 1149 | spin_unlock_wr(&fdp->fd_spin); |
| 1150 | return (0); |
| 1151 | } |
| 1152 | |
| 1153 | /* |
| 1154 | * Check to see whether n user file descriptors |
| 1155 | * are available to the process p. |
| 1156 | * |
| 1157 | * MPSAFE |
| 1158 | */ |
| 1159 | int |
| 1160 | fdavail(struct proc *p, int n) |
| 1161 | { |
| 1162 | struct filedesc *fdp = p->p_fd; |
| 1163 | struct fdnode *fdnode; |
| 1164 | int i, lim, last; |
| 1165 | |
| 1166 | spin_lock_rd(&p->p_limit->p_spin); |
| 1167 | lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); |
| 1168 | spin_unlock_rd(&p->p_limit->p_spin); |
| 1169 | |
| 1170 | spin_lock_rd(&fdp->fd_spin); |
| 1171 | if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { |
| 1172 | spin_unlock_rd(&fdp->fd_spin); |
| 1173 | return (1); |
| 1174 | } |
| 1175 | last = min(fdp->fd_nfiles, lim); |
| 1176 | fdnode = &fdp->fd_files[fdp->fd_freefile]; |
| 1177 | for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { |
| 1178 | if (fdnode->fp == NULL && --n <= 0) { |
| 1179 | spin_unlock_rd(&fdp->fd_spin); |
| 1180 | return (1); |
| 1181 | } |
| 1182 | } |
| 1183 | spin_unlock_rd(&fdp->fd_spin); |
| 1184 | return (0); |
| 1185 | } |
| 1186 | |
| 1187 | /* |
| 1188 | * Revoke open descriptors referencing (f_data, f_type) |
| 1189 | * |
| 1190 | * Any revoke executed within a prison is only able to |
| 1191 | * revoke descriptors for processes within that prison. |
| 1192 | * |
| 1193 | * Returns 0 on success or an error code. |
| 1194 | */ |
| 1195 | struct fdrevoke_info { |
| 1196 | void *data; |
| 1197 | short type; |
| 1198 | short unused; |
| 1199 | int count; |
| 1200 | int intransit; |
| 1201 | struct ucred *cred; |
| 1202 | struct file *nfp; |
| 1203 | }; |
| 1204 | |
| 1205 | static int fdrevoke_check_callback(struct file *fp, void *vinfo); |
| 1206 | static int fdrevoke_proc_callback(struct proc *p, void *vinfo); |
| 1207 | |
| 1208 | int |
| 1209 | fdrevoke(void *f_data, short f_type, struct ucred *cred) |
| 1210 | { |
| 1211 | struct fdrevoke_info info; |
| 1212 | int error; |
| 1213 | |
| 1214 | bzero(&info, sizeof(info)); |
| 1215 | info.data = f_data; |
| 1216 | info.type = f_type; |
| 1217 | info.cred = cred; |
| 1218 | error = falloc(NULL, &info.nfp, NULL); |
| 1219 | if (error) |
| 1220 | return (error); |
| 1221 | |
| 1222 | /* |
| 1223 | * Scan the file pointer table once. dups do not dup file pointers, |
| 1224 | * only descriptors, so there is no leak. Set FREVOKED on the fps |
| 1225 | * being revoked. |
| 1226 | */ |
| 1227 | allfiles_scan_exclusive(fdrevoke_check_callback, &info); |
| 1228 | |
| 1229 | /* |
| 1230 | * If any fps were marked track down the related descriptors |
| 1231 | * and close them. Any dup()s at this point will notice |
| 1232 | * the FREVOKED already set in the fp and do the right thing. |
| 1233 | * |
| 1234 | * Any fps with non-zero msgcounts (aka sent over a unix-domain |
| 1235 | * socket) bumped the intransit counter and will require a |
| 1236 | * scan. Races against fps leaving the socket are closed by |
| 1237 | * the socket code checking for FREVOKED. |
| 1238 | */ |
| 1239 | if (info.count) |
| 1240 | allproc_scan(fdrevoke_proc_callback, &info); |
| 1241 | if (info.intransit) |
| 1242 | unp_revoke_gc(info.nfp); |
| 1243 | fdrop(info.nfp); |
| 1244 | return(0); |
| 1245 | } |
| 1246 | |
| 1247 | /* |
| 1248 | * Locate matching file pointers directly. |
| 1249 | */ |
| 1250 | static int |
| 1251 | fdrevoke_check_callback(struct file *fp, void *vinfo) |
| 1252 | { |
| 1253 | struct fdrevoke_info *info = vinfo; |
| 1254 | |
| 1255 | /* |
| 1256 | * File pointers already flagged for revokation are skipped. |
| 1257 | */ |
| 1258 | if (fp->f_flag & FREVOKED) |
| 1259 | return(0); |
| 1260 | |
| 1261 | /* |
| 1262 | * If revoking from a prison file pointers created outside of |
| 1263 | * that prison, or file pointers without creds, cannot be revoked. |
| 1264 | */ |
| 1265 | if (info->cred->cr_prison && |
| 1266 | (fp->f_cred == NULL || |
| 1267 | info->cred->cr_prison != fp->f_cred->cr_prison)) { |
| 1268 | return(0); |
| 1269 | } |
| 1270 | |
| 1271 | /* |
| 1272 | * If the file pointer matches then mark it for revocation. The |
| 1273 | * flag is currently only used by unp_revoke_gc(). |
| 1274 | * |
| 1275 | * info->count is a heuristic and can race in a SMP environment. |
| 1276 | */ |
| 1277 | if (info->data == fp->f_data && info->type == fp->f_type) { |
| 1278 | atomic_set_int(&fp->f_flag, FREVOKED); |
| 1279 | info->count += fp->f_count; |
| 1280 | if (fp->f_msgcount) |
| 1281 | ++info->intransit; |
| 1282 | } |
| 1283 | return(0); |
| 1284 | } |
| 1285 | |
| 1286 | /* |
| 1287 | * Locate matching file pointers via process descriptor tables. |
| 1288 | */ |
| 1289 | static int |
| 1290 | fdrevoke_proc_callback(struct proc *p, void *vinfo) |
| 1291 | { |
| 1292 | struct fdrevoke_info *info = vinfo; |
| 1293 | struct filedesc *fdp; |
| 1294 | struct file *fp; |
| 1295 | int n; |
| 1296 | |
| 1297 | if (p->p_stat == SIDL || p->p_stat == SZOMB) |
| 1298 | return(0); |
| 1299 | if (info->cred->cr_prison && |
| 1300 | info->cred->cr_prison != p->p_ucred->cr_prison) { |
| 1301 | return(0); |
| 1302 | } |
| 1303 | |
| 1304 | /* |
| 1305 | * If the controlling terminal of the process matches the |
| 1306 | * vnode being revoked we clear the controlling terminal. |
| 1307 | * |
| 1308 | * The normal spec_close() may not catch this because it |
| 1309 | * uses curproc instead of p. |
| 1310 | */ |
| 1311 | if (p->p_session && info->type == DTYPE_VNODE && |
| 1312 | info->data == p->p_session->s_ttyvp) { |
| 1313 | p->p_session->s_ttyvp = NULL; |
| 1314 | vrele(info->data); |
| 1315 | } |
| 1316 | |
| 1317 | /* |
| 1318 | * Locate and close any matching file descriptors. |
| 1319 | */ |
| 1320 | if ((fdp = p->p_fd) == NULL) |
| 1321 | return(0); |
| 1322 | spin_lock_wr(&fdp->fd_spin); |
| 1323 | for (n = 0; n < fdp->fd_nfiles; ++n) { |
| 1324 | if ((fp = fdp->fd_files[n].fp) == NULL) |
| 1325 | continue; |
| 1326 | if (fp->f_flag & FREVOKED) { |
| 1327 | fhold(info->nfp); |
| 1328 | fdp->fd_files[n].fp = info->nfp; |
| 1329 | spin_unlock_wr(&fdp->fd_spin); |
| 1330 | closef(fp, p); |
| 1331 | spin_lock_wr(&fdp->fd_spin); |
| 1332 | --info->count; |
| 1333 | } |
| 1334 | } |
| 1335 | spin_unlock_wr(&fdp->fd_spin); |
| 1336 | return(0); |
| 1337 | } |
| 1338 | |
| 1339 | /* |
| 1340 | * falloc: |
| 1341 | * Create a new open file structure and reserve a file decriptor |
| 1342 | * for the process that refers to it. |
| 1343 | * |
| 1344 | * Root creds are checked using p, or assumed if p is NULL. If |
| 1345 | * resultfd is non-NULL then p must also be non-NULL. No file |
| 1346 | * descriptor is reserved if resultfd is NULL. |
| 1347 | * |
| 1348 | * A file pointer with a refcount of 1 is returned. Note that the |
| 1349 | * file pointer is NOT associated with the descriptor. If falloc |
| 1350 | * returns success, fsetfd() MUST be called to either associate the |
| 1351 | * file pointer or clear the reservation. |
| 1352 | * |
| 1353 | * MPSAFE |
| 1354 | */ |
| 1355 | int |
| 1356 | falloc(struct proc *p, struct file **resultfp, int *resultfd) |
| 1357 | { |
| 1358 | static struct timeval lastfail; |
| 1359 | static int curfail; |
| 1360 | struct file *fp; |
| 1361 | int error; |
| 1362 | |
| 1363 | fp = NULL; |
| 1364 | |
| 1365 | /* |
| 1366 | * Handle filetable full issues and root overfill. |
| 1367 | */ |
| 1368 | if (nfiles >= maxfiles - maxfilesrootres && |
| 1369 | ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) { |
| 1370 | if (ppsratecheck(&lastfail, &curfail, 1)) { |
| 1371 | kprintf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n", |
| 1372 | (p ? p->p_ucred->cr_ruid : -1)); |
| 1373 | } |
| 1374 | error = ENFILE; |
| 1375 | goto done; |
| 1376 | } |
| 1377 | |
| 1378 | /* |
| 1379 | * Allocate a new file descriptor. |
| 1380 | */ |
| 1381 | fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO); |
| 1382 | spin_init(&fp->f_spin); |
| 1383 | fp->f_count = 1; |
| 1384 | fp->f_ops = &badfileops; |
| 1385 | fp->f_seqcount = 1; |
| 1386 | if (p) |
| 1387 | fp->f_cred = crhold(p->p_ucred); |
| 1388 | else |
| 1389 | fp->f_cred = crhold(proc0.p_ucred); |
| 1390 | spin_lock_wr(&filehead_spin); |
| 1391 | nfiles++; |
| 1392 | LIST_INSERT_HEAD(&filehead, fp, f_list); |
| 1393 | spin_unlock_wr(&filehead_spin); |
| 1394 | if (resultfd) { |
| 1395 | if ((error = fdalloc(p, 0, resultfd)) != 0) { |
| 1396 | fdrop(fp); |
| 1397 | fp = NULL; |
| 1398 | } |
| 1399 | } else { |
| 1400 | error = 0; |
| 1401 | } |
| 1402 | done: |
| 1403 | *resultfp = fp; |
| 1404 | return (error); |
| 1405 | } |
| 1406 | |
| 1407 | /* |
| 1408 | * MPSAFE |
| 1409 | */ |
| 1410 | static |
| 1411 | int |
| 1412 | checkfpclosed(struct filedesc *fdp, int fd, struct file *fp) |
| 1413 | { |
| 1414 | int error; |
| 1415 | |
| 1416 | spin_lock_rd(&fdp->fd_spin); |
| 1417 | if ((unsigned) fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) |
| 1418 | error = EBADF; |
| 1419 | else |
| 1420 | error = 0; |
| 1421 | spin_unlock_rd(&fdp->fd_spin); |
| 1422 | return (error); |
| 1423 | } |
| 1424 | |
| 1425 | /* |
| 1426 | * Associate a file pointer with a previously reserved file descriptor. |
| 1427 | * This function always succeeds. |
| 1428 | * |
| 1429 | * If fp is NULL, the file descriptor is returned to the pool. |
| 1430 | */ |
| 1431 | |
| 1432 | /* |
| 1433 | * MPSAFE (exclusive spinlock must be held on call) |
| 1434 | */ |
| 1435 | static void |
| 1436 | fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) |
| 1437 | { |
| 1438 | KKASSERT((unsigned)fd < fdp->fd_nfiles); |
| 1439 | KKASSERT(fdp->fd_files[fd].reserved != 0); |
| 1440 | if (fp) { |
| 1441 | fhold(fp); |
| 1442 | fdp->fd_files[fd].fp = fp; |
| 1443 | fdp->fd_files[fd].reserved = 0; |
| 1444 | if (fp->f_type == DTYPE_KQUEUE) { |
| 1445 | if (fdp->fd_knlistsize < 0) |
| 1446 | fdp->fd_knlistsize = 0; |
| 1447 | } |
| 1448 | } else { |
| 1449 | fdp->fd_files[fd].reserved = 0; |
| 1450 | fdreserve_locked(fdp, fd, -1); |
| 1451 | fdfixup_locked(fdp, fd); |
| 1452 | } |
| 1453 | } |
| 1454 | |
| 1455 | /* |
| 1456 | * MPSAFE |
| 1457 | */ |
| 1458 | void |
| 1459 | fsetfd(struct proc *p, struct file *fp, int fd) |
| 1460 | { |
| 1461 | struct filedesc *fdp = p->p_fd; |
| 1462 | |
| 1463 | spin_lock_wr(&fdp->fd_spin); |
| 1464 | fsetfd_locked(fdp, fp, fd); |
| 1465 | spin_unlock_wr(&fdp->fd_spin); |
| 1466 | } |
| 1467 | |
| 1468 | /* |
| 1469 | * MPSAFE (exclusive spinlock must be held on call) |
| 1470 | */ |
| 1471 | static |
| 1472 | struct file * |
| 1473 | funsetfd_locked(struct filedesc *fdp, int fd) |
| 1474 | { |
| 1475 | struct file *fp; |
| 1476 | |
| 1477 | if ((unsigned)fd >= fdp->fd_nfiles) |
| 1478 | return (NULL); |
| 1479 | if ((fp = fdp->fd_files[fd].fp) == NULL) |
| 1480 | return (NULL); |
| 1481 | fdp->fd_files[fd].fp = NULL; |
| 1482 | fdp->fd_files[fd].fileflags = 0; |
| 1483 | |
| 1484 | fdreserve_locked(fdp, fd, -1); |
| 1485 | fdfixup_locked(fdp, fd); |
| 1486 | return(fp); |
| 1487 | } |
| 1488 | |
| 1489 | /* |
| 1490 | * MPSAFE |
| 1491 | */ |
| 1492 | int |
| 1493 | fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) |
| 1494 | { |
| 1495 | int error; |
| 1496 | |
| 1497 | spin_lock_rd(&fdp->fd_spin); |
| 1498 | if (((u_int)fd) >= fdp->fd_nfiles) { |
| 1499 | error = EBADF; |
| 1500 | } else if (fdp->fd_files[fd].fp == NULL) { |
| 1501 | error = EBADF; |
| 1502 | } else { |
| 1503 | *flagsp = fdp->fd_files[fd].fileflags; |
| 1504 | error = 0; |
| 1505 | } |
| 1506 | spin_unlock_rd(&fdp->fd_spin); |
| 1507 | return (error); |
| 1508 | } |
| 1509 | |
| 1510 | /* |
| 1511 | * MPSAFE |
| 1512 | */ |
| 1513 | int |
| 1514 | fsetfdflags(struct filedesc *fdp, int fd, int add_flags) |
| 1515 | { |
| 1516 | int error; |
| 1517 | |
| 1518 | spin_lock_wr(&fdp->fd_spin); |
| 1519 | if (((u_int)fd) >= fdp->fd_nfiles) { |
| 1520 | error = EBADF; |
| 1521 | } else if (fdp->fd_files[fd].fp == NULL) { |
| 1522 | error = EBADF; |
| 1523 | } else { |
| 1524 | fdp->fd_files[fd].fileflags |= add_flags; |
| 1525 | error = 0; |
| 1526 | } |
| 1527 | spin_unlock_wr(&fdp->fd_spin); |
| 1528 | return (error); |
| 1529 | } |
| 1530 | |
| 1531 | /* |
| 1532 | * MPSAFE |
| 1533 | */ |
| 1534 | int |
| 1535 | fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) |
| 1536 | { |
| 1537 | int error; |
| 1538 | |
| 1539 | spin_lock_wr(&fdp->fd_spin); |
| 1540 | if (((u_int)fd) >= fdp->fd_nfiles) { |
| 1541 | error = EBADF; |
| 1542 | } else if (fdp->fd_files[fd].fp == NULL) { |
| 1543 | error = EBADF; |
| 1544 | } else { |
| 1545 | fdp->fd_files[fd].fileflags &= ~rem_flags; |
| 1546 | error = 0; |
| 1547 | } |
| 1548 | spin_unlock_wr(&fdp->fd_spin); |
| 1549 | return (error); |
| 1550 | } |
| 1551 | |
| 1552 | void |
| 1553 | fsetcred(struct file *fp, struct ucred *cr) |
| 1554 | { |
| 1555 | crhold(cr); |
| 1556 | crfree(fp->f_cred); |
| 1557 | fp->f_cred = cr; |
| 1558 | } |
| 1559 | |
| 1560 | /* |
| 1561 | * Free a file descriptor. |
| 1562 | */ |
| 1563 | static |
| 1564 | void |
| 1565 | ffree(struct file *fp) |
| 1566 | { |
| 1567 | KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); |
| 1568 | spin_lock_wr(&filehead_spin); |
| 1569 | LIST_REMOVE(fp, f_list); |
| 1570 | nfiles--; |
| 1571 | spin_unlock_wr(&filehead_spin); |
| 1572 | crfree(fp->f_cred); |
| 1573 | if (fp->f_nchandle.ncp) |
| 1574 | cache_drop(&fp->f_nchandle); |
| 1575 | kfree(fp, M_FILE); |
| 1576 | } |
| 1577 | |
| 1578 | /* |
| 1579 | * called from init_main, initialize filedesc0 for proc0. |
| 1580 | */ |
| 1581 | void |
| 1582 | fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) |
| 1583 | { |
| 1584 | p0->p_fd = fdp0; |
| 1585 | p0->p_fdtol = NULL; |
| 1586 | fdp0->fd_refcnt = 1; |
| 1587 | fdp0->fd_cmask = cmask; |
| 1588 | fdp0->fd_files = fdp0->fd_builtin_files; |
| 1589 | fdp0->fd_nfiles = NDFILE; |
| 1590 | fdp0->fd_lastfile = -1; |
| 1591 | spin_init(&fdp0->fd_spin); |
| 1592 | } |
| 1593 | |
| 1594 | /* |
| 1595 | * Build a new filedesc structure. |
| 1596 | * |
| 1597 | * NOT MPSAFE (vref) |
| 1598 | */ |
| 1599 | struct filedesc * |
| 1600 | fdinit(struct proc *p) |
| 1601 | { |
| 1602 | struct filedesc *newfdp; |
| 1603 | struct filedesc *fdp = p->p_fd; |
| 1604 | |
| 1605 | newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); |
| 1606 | spin_lock_rd(&fdp->fd_spin); |
| 1607 | if (fdp->fd_cdir) { |
| 1608 | newfdp->fd_cdir = fdp->fd_cdir; |
| 1609 | vref(newfdp->fd_cdir); |
| 1610 | cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); |
| 1611 | } |
| 1612 | |
| 1613 | /* |
| 1614 | * rdir may not be set in e.g. proc0 or anything vm_fork'd off of |
| 1615 | * proc0, but should unconditionally exist in other processes. |
| 1616 | */ |
| 1617 | if (fdp->fd_rdir) { |
| 1618 | newfdp->fd_rdir = fdp->fd_rdir; |
| 1619 | vref(newfdp->fd_rdir); |
| 1620 | cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); |
| 1621 | } |
| 1622 | if (fdp->fd_jdir) { |
| 1623 | newfdp->fd_jdir = fdp->fd_jdir; |
| 1624 | vref(newfdp->fd_jdir); |
| 1625 | cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); |
| 1626 | } |
| 1627 | spin_unlock_rd(&fdp->fd_spin); |
| 1628 | |
| 1629 | /* Create the file descriptor table. */ |
| 1630 | newfdp->fd_refcnt = 1; |
| 1631 | newfdp->fd_cmask = cmask; |
| 1632 | newfdp->fd_files = newfdp->fd_builtin_files; |
| 1633 | newfdp->fd_nfiles = NDFILE; |
| 1634 | newfdp->fd_knlistsize = -1; |
| 1635 | newfdp->fd_lastfile = -1; |
| 1636 | spin_init(&newfdp->fd_spin); |
| 1637 | |
| 1638 | return (newfdp); |
| 1639 | } |
| 1640 | |
| 1641 | /* |
| 1642 | * Share a filedesc structure. |
| 1643 | * |
| 1644 | * MPSAFE |
| 1645 | */ |
| 1646 | struct filedesc * |
| 1647 | fdshare(struct proc *p) |
| 1648 | { |
| 1649 | struct filedesc *fdp; |
| 1650 | |
| 1651 | fdp = p->p_fd; |
| 1652 | spin_lock_wr(&fdp->fd_spin); |
| 1653 | fdp->fd_refcnt++; |
| 1654 | spin_unlock_wr(&fdp->fd_spin); |
| 1655 | return (fdp); |
| 1656 | } |
| 1657 | |
| 1658 | /* |
| 1659 | * Copy a filedesc structure. |
| 1660 | * |
| 1661 | * MPSAFE |
| 1662 | */ |
| 1663 | struct filedesc * |
| 1664 | fdcopy(struct proc *p) |
| 1665 | { |
| 1666 | struct filedesc *fdp = p->p_fd; |
| 1667 | struct filedesc *newfdp; |
| 1668 | struct fdnode *fdnode; |
| 1669 | int i; |
| 1670 | int ni; |
| 1671 | |
| 1672 | /* |
| 1673 | * Certain daemons might not have file descriptors. |
| 1674 | */ |
| 1675 | if (fdp == NULL) |
| 1676 | return (NULL); |
| 1677 | |
| 1678 | /* |
| 1679 | * Allocate the new filedesc and fd_files[] array. This can race |
| 1680 | * with operations by other threads on the fdp so we have to be |
| 1681 | * careful. |
| 1682 | */ |
| 1683 | newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK | M_ZERO); |
| 1684 | again: |
| 1685 | spin_lock_rd(&fdp->fd_spin); |
| 1686 | if (fdp->fd_lastfile < NDFILE) { |
| 1687 | newfdp->fd_files = newfdp->fd_builtin_files; |
| 1688 | i = NDFILE; |
| 1689 | } else { |
| 1690 | /* |
| 1691 | * We have to allocate (N^2-1) entries for our in-place |
| 1692 | * binary tree. Allow the table to shrink. |
| 1693 | */ |
| 1694 | i = fdp->fd_nfiles; |
| 1695 | ni = (i - 1) / 2; |
| 1696 | while (ni > fdp->fd_lastfile && ni > NDFILE) { |
| 1697 | i = ni; |
| 1698 | ni = (i - 1) / 2; |
| 1699 | } |
| 1700 | spin_unlock_rd(&fdp->fd_spin); |
| 1701 | newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), |
| 1702 | M_FILEDESC, M_WAITOK | M_ZERO); |
| 1703 | |
| 1704 | /* |
| 1705 | * Check for race, retry |
| 1706 | */ |
| 1707 | spin_lock_rd(&fdp->fd_spin); |
| 1708 | if (i <= fdp->fd_lastfile) { |
| 1709 | spin_unlock_rd(&fdp->fd_spin); |
| 1710 | kfree(newfdp->fd_files, M_FILEDESC); |
| 1711 | goto again; |
| 1712 | } |
| 1713 | } |
| 1714 | |
| 1715 | /* |
| 1716 | * Dup the remaining fields. vref() and cache_hold() can be |
| 1717 | * safely called while holding the read spinlock on fdp. |
| 1718 | * |
| 1719 | * The read spinlock on fdp is still being held. |
| 1720 | * |
| 1721 | * NOTE: vref and cache_hold calls for the case where the vnode |
| 1722 | * or cache entry already has at least one ref may be called |
| 1723 | * while holding spin locks. |
| 1724 | */ |
| 1725 | if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { |
| 1726 | vref(newfdp->fd_cdir); |
| 1727 | cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); |
| 1728 | } |
| 1729 | /* |
| 1730 | * We must check for fd_rdir here, at least for now because |
| 1731 | * the init process is created before we have access to the |
| 1732 | * rootvode to take a reference to it. |
| 1733 | */ |
| 1734 | if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { |
| 1735 | vref(newfdp->fd_rdir); |
| 1736 | cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); |
| 1737 | } |
| 1738 | if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { |
| 1739 | vref(newfdp->fd_jdir); |
| 1740 | cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); |
| 1741 | } |
| 1742 | newfdp->fd_refcnt = 1; |
| 1743 | newfdp->fd_nfiles = i; |
| 1744 | newfdp->fd_lastfile = fdp->fd_lastfile; |
| 1745 | newfdp->fd_freefile = fdp->fd_freefile; |
| 1746 | newfdp->fd_cmask = fdp->fd_cmask; |
| 1747 | newfdp->fd_knlist = NULL; |
| 1748 | newfdp->fd_knlistsize = -1; |
| 1749 | newfdp->fd_knhash = NULL; |
| 1750 | newfdp->fd_knhashmask = 0; |
| 1751 | spin_init(&newfdp->fd_spin); |
| 1752 | |
| 1753 | /* |
| 1754 | * Copy the descriptor table through (i). This also copies the |
| 1755 | * allocation state. Then go through and ref the file pointers |
| 1756 | * and clean up any KQ descriptors. |
| 1757 | * |
| 1758 | * kq descriptors cannot be copied. Since we haven't ref'd the |
| 1759 | * copied files yet we can ignore the return value from funsetfd(). |
| 1760 | * |
| 1761 | * The read spinlock on fdp is still being held. |
| 1762 | */ |
| 1763 | bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); |
| 1764 | for (i = 0 ; i < newfdp->fd_nfiles; ++i) { |
| 1765 | fdnode = &newfdp->fd_files[i]; |
| 1766 | if (fdnode->reserved) { |
| 1767 | fdreserve_locked(newfdp, i, -1); |
| 1768 | fdnode->reserved = 0; |
| 1769 | fdfixup_locked(newfdp, i); |
| 1770 | } else if (fdnode->fp) { |
| 1771 | if (fdnode->fp->f_type == DTYPE_KQUEUE) { |
| 1772 | (void)funsetfd_locked(newfdp, i); |
| 1773 | } else { |
| 1774 | fhold(fdnode->fp); |
| 1775 | } |
| 1776 | } |
| 1777 | } |
| 1778 | spin_unlock_rd(&fdp->fd_spin); |
| 1779 | return (newfdp); |
| 1780 | } |
| 1781 | |
| 1782 | /* |
| 1783 | * Release a filedesc structure. |
| 1784 | * |
| 1785 | * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) |
| 1786 | */ |
| 1787 | void |
| 1788 | fdfree(struct proc *p) |
| 1789 | { |
| 1790 | struct filedesc *fdp = p->p_fd; |
| 1791 | struct fdnode *fdnode; |
| 1792 | int i; |
| 1793 | struct filedesc_to_leader *fdtol; |
| 1794 | struct file *fp; |
| 1795 | struct vnode *vp; |
| 1796 | struct flock lf; |
| 1797 | |
| 1798 | /* Certain daemons might not have file descriptors. */ |
| 1799 | if (fdp == NULL) |
| 1800 | return; |
| 1801 | |
| 1802 | /* |
| 1803 | * Severe messing around to follow |
| 1804 | */ |
| 1805 | spin_lock_wr(&fdp->fd_spin); |
| 1806 | |
| 1807 | /* Check for special need to clear POSIX style locks */ |
| 1808 | fdtol = p->p_fdtol; |
| 1809 | if (fdtol != NULL) { |
| 1810 | KASSERT(fdtol->fdl_refcount > 0, |
| 1811 | ("filedesc_to_refcount botch: fdl_refcount=%d", |
| 1812 | fdtol->fdl_refcount)); |
| 1813 | if (fdtol->fdl_refcount == 1 && |
| 1814 | (p->p_leader->p_flag & P_ADVLOCK) != 0) { |
| 1815 | for (i = 0; i <= fdp->fd_lastfile; ++i) { |
| 1816 | fdnode = &fdp->fd_files[i]; |
| 1817 | if (fdnode->fp == NULL || |
| 1818 | fdnode->fp->f_type != DTYPE_VNODE) { |
| 1819 | continue; |
| 1820 | } |
| 1821 | fp = fdnode->fp; |
| 1822 | fhold(fp); |
| 1823 | spin_unlock_wr(&fdp->fd_spin); |
| 1824 | |
| 1825 | lf.l_whence = SEEK_SET; |
| 1826 | lf.l_start = 0; |
| 1827 | lf.l_len = 0; |
| 1828 | lf.l_type = F_UNLCK; |
| 1829 | vp = (struct vnode *)fp->f_data; |
| 1830 | (void) VOP_ADVLOCK(vp, |
| 1831 | (caddr_t)p->p_leader, |
| 1832 | F_UNLCK, |
| 1833 | &lf, |
| 1834 | F_POSIX); |
| 1835 | fdrop(fp); |
| 1836 | spin_lock_wr(&fdp->fd_spin); |
| 1837 | } |
| 1838 | } |
| 1839 | retry: |
| 1840 | if (fdtol->fdl_refcount == 1) { |
| 1841 | if (fdp->fd_holdleaderscount > 0 && |
| 1842 | (p->p_leader->p_flag & P_ADVLOCK) != 0) { |
| 1843 | /* |
| 1844 | * close() or do_dup() has cleared a reference |
| 1845 | * in a shared file descriptor table. |
| 1846 | */ |
| 1847 | fdp->fd_holdleaderswakeup = 1; |
| 1848 | msleep(&fdp->fd_holdleaderscount, |
| 1849 | &fdp->fd_spin, 0, "fdlhold", 0); |
| 1850 | goto retry; |
| 1851 | } |
| 1852 | if (fdtol->fdl_holdcount > 0) { |
| 1853 | /* |
| 1854 | * Ensure that fdtol->fdl_leader |
| 1855 | * remains valid in closef(). |
| 1856 | */ |
| 1857 | fdtol->fdl_wakeup = 1; |
| 1858 | msleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); |
| 1859 | goto retry; |
| 1860 | } |
| 1861 | } |
| 1862 | fdtol->fdl_refcount--; |
| 1863 | if (fdtol->fdl_refcount == 0 && |
| 1864 | fdtol->fdl_holdcount == 0) { |
| 1865 | fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; |
| 1866 | fdtol->fdl_prev->fdl_next = fdtol->fdl_next; |
| 1867 | } else { |
| 1868 | fdtol = NULL; |
| 1869 | } |
| 1870 | p->p_fdtol = NULL; |
| 1871 | if (fdtol != NULL) { |
| 1872 | spin_unlock_wr(&fdp->fd_spin); |
| 1873 | kfree(fdtol, M_FILEDESC_TO_LEADER); |
| 1874 | spin_lock_wr(&fdp->fd_spin); |
| 1875 | } |
| 1876 | } |
| 1877 | if (--fdp->fd_refcnt > 0) { |
| 1878 | spin_unlock_wr(&fdp->fd_spin); |
| 1879 | return; |
| 1880 | } |
| 1881 | spin_unlock_wr(&fdp->fd_spin); |
| 1882 | |
| 1883 | /* |
| 1884 | * we are the last reference to the structure, we can |
| 1885 | * safely assume it will not change out from under us. |
| 1886 | */ |
| 1887 | for (i = 0; i <= fdp->fd_lastfile; ++i) { |
| 1888 | if (fdp->fd_files[i].fp) |
| 1889 | closef(fdp->fd_files[i].fp, p); |
| 1890 | } |
| 1891 | if (fdp->fd_files != fdp->fd_builtin_files) |
| 1892 | kfree(fdp->fd_files, M_FILEDESC); |
| 1893 | if (fdp->fd_cdir) { |
| 1894 | cache_drop(&fdp->fd_ncdir); |
| 1895 | vrele(fdp->fd_cdir); |
| 1896 | } |
| 1897 | if (fdp->fd_rdir) { |
| 1898 | cache_drop(&fdp->fd_nrdir); |
| 1899 | vrele(fdp->fd_rdir); |
| 1900 | } |
| 1901 | if (fdp->fd_jdir) { |
| 1902 | cache_drop(&fdp->fd_njdir); |
| 1903 | vrele(fdp->fd_jdir); |
| 1904 | } |
| 1905 | if (fdp->fd_knlist) |
| 1906 | kfree(fdp->fd_knlist, M_KQUEUE); |
| 1907 | if (fdp->fd_knhash) |
| 1908 | kfree(fdp->fd_knhash, M_KQUEUE); |
| 1909 | kfree(fdp, M_FILEDESC); |
| 1910 | } |
| 1911 | |
| 1912 | /* |
| 1913 | * Retrieve and reference the file pointer associated with a descriptor. |
| 1914 | * |
| 1915 | * MPSAFE |
| 1916 | */ |
| 1917 | struct file * |
| 1918 | holdfp(struct filedesc *fdp, int fd, int flag) |
| 1919 | { |
| 1920 | struct file* fp; |
| 1921 | |
| 1922 | spin_lock_rd(&fdp->fd_spin); |
| 1923 | if (((u_int)fd) >= fdp->fd_nfiles) { |
| 1924 | fp = NULL; |
| 1925 | goto done; |
| 1926 | } |
| 1927 | if ((fp = fdp->fd_files[fd].fp) == NULL) |
| 1928 | goto done; |
| 1929 | if ((fp->f_flag & flag) == 0 && flag != -1) { |
| 1930 | fp = NULL; |
| 1931 | goto done; |
| 1932 | } |
| 1933 | fhold(fp); |
| 1934 | done: |
| 1935 | spin_unlock_rd(&fdp->fd_spin); |
| 1936 | return (fp); |
| 1937 | } |
| 1938 | |
| 1939 | /* |
| 1940 | * holdsock() - load the struct file pointer associated |
| 1941 | * with a socket into *fpp. If an error occurs, non-zero |
| 1942 | * will be returned and *fpp will be set to NULL. |
| 1943 | * |
| 1944 | * MPSAFE |
| 1945 | */ |
| 1946 | int |
| 1947 | holdsock(struct filedesc *fdp, int fd, struct file **fpp) |
| 1948 | { |
| 1949 | struct file *fp; |
| 1950 | int error; |
| 1951 | |
| 1952 | spin_lock_rd(&fdp->fd_spin); |
| 1953 | if ((unsigned)fd >= fdp->fd_nfiles) { |
| 1954 | error = EBADF; |
| 1955 | fp = NULL; |
| 1956 | goto done; |
| 1957 | } |
| 1958 | if ((fp = fdp->fd_files[fd].fp) == NULL) { |
| 1959 | error = EBADF; |
| 1960 | goto done; |
| 1961 | } |
| 1962 | if (fp->f_type != DTYPE_SOCKET) { |
| 1963 | error = ENOTSOCK; |
| 1964 | goto done; |
| 1965 | } |
| 1966 | fhold(fp); |
| 1967 | error = 0; |
| 1968 | done: |
| 1969 | spin_unlock_rd(&fdp->fd_spin); |
| 1970 | *fpp = fp; |
| 1971 | return (error); |
| 1972 | } |
| 1973 | |
| 1974 | /* |
| 1975 | * Convert a user file descriptor to a held file pointer. |
| 1976 | * |
| 1977 | * MPSAFE |
| 1978 | */ |
| 1979 | int |
| 1980 | holdvnode(struct filedesc *fdp, int fd, struct file **fpp) |
| 1981 | { |
| 1982 | struct file *fp; |
| 1983 | int error; |
| 1984 | |
| 1985 | spin_lock_rd(&fdp->fd_spin); |
| 1986 | if ((unsigned)fd >= fdp->fd_nfiles) { |
| 1987 | error = EBADF; |
| 1988 | fp = NULL; |
| 1989 | goto done; |
| 1990 | } |
| 1991 | if ((fp = fdp->fd_files[fd].fp) == NULL) { |
| 1992 | error = EBADF; |
| 1993 | goto done; |
| 1994 | } |
| 1995 | if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { |
| 1996 | fp = NULL; |
| 1997 | error = EINVAL; |
| 1998 | goto done; |
| 1999 | } |
| 2000 | fhold(fp); |
| 2001 | error = 0; |
| 2002 | done: |
| 2003 | spin_unlock_rd(&fdp->fd_spin); |
| 2004 | *fpp = fp; |
| 2005 | return (error); |
| 2006 | } |
| 2007 | |
| 2008 | /* |
| 2009 | * For setugid programs, we don't want to people to use that setugidness |
| 2010 | * to generate error messages which write to a file which otherwise would |
| 2011 | * otherwise be off-limits to the process. |
| 2012 | * |
| 2013 | * This is a gross hack to plug the hole. A better solution would involve |
| 2014 | * a special vop or other form of generalized access control mechanism. We |
| 2015 | * go ahead and just reject all procfs file systems accesses as dangerous. |
| 2016 | * |
| 2017 | * Since setugidsafety calls this only for fd 0, 1 and 2, this check is |
| 2018 | * sufficient. We also don't for check setugidness since we know we are. |
| 2019 | */ |
| 2020 | static int |
| 2021 | is_unsafe(struct file *fp) |
| 2022 | { |
| 2023 | if (fp->f_type == DTYPE_VNODE && |
| 2024 | ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) |
| 2025 | return (1); |
| 2026 | return (0); |
| 2027 | } |
| 2028 | |
| 2029 | /* |
| 2030 | * Make this setguid thing safe, if at all possible. |
| 2031 | * |
| 2032 | * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() |
| 2033 | */ |
| 2034 | void |
| 2035 | setugidsafety(struct proc *p) |
| 2036 | { |
| 2037 | struct filedesc *fdp = p->p_fd; |
| 2038 | int i; |
| 2039 | |
| 2040 | /* Certain daemons might not have file descriptors. */ |
| 2041 | if (fdp == NULL) |
| 2042 | return; |
| 2043 | |
| 2044 | /* |
| 2045 | * note: fdp->fd_files may be reallocated out from under us while |
| 2046 | * we are blocked in a close. Be careful! |
| 2047 | */ |
| 2048 | for (i = 0; i <= fdp->fd_lastfile; i++) { |
| 2049 | if (i > 2) |
| 2050 | break; |
| 2051 | if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { |
| 2052 | struct file *fp; |
| 2053 | |
| 2054 | if (i < fdp->fd_knlistsize) |
| 2055 | knote_fdclose(p, i); |
| 2056 | /* |
| 2057 | * NULL-out descriptor prior to close to avoid |
| 2058 | * a race while close blocks. |
| 2059 | */ |
| 2060 | if ((fp = funsetfd_locked(fdp, i)) != NULL) |
| 2061 | closef(fp, p); |
| 2062 | } |
| 2063 | } |
| 2064 | } |
| 2065 | |
| 2066 | /* |
| 2067 | * Close any files on exec? |
| 2068 | * |
| 2069 | * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() |
| 2070 | */ |
| 2071 | void |
| 2072 | fdcloseexec(struct proc *p) |
| 2073 | { |
| 2074 | struct filedesc *fdp = p->p_fd; |
| 2075 | int i; |
| 2076 | |
| 2077 | /* Certain daemons might not have file descriptors. */ |
| 2078 | if (fdp == NULL) |
| 2079 | return; |
| 2080 | |
| 2081 | /* |
| 2082 | * We cannot cache fd_files since operations may block and rip |
| 2083 | * them out from under us. |
| 2084 | */ |
| 2085 | for (i = 0; i <= fdp->fd_lastfile; i++) { |
| 2086 | if (fdp->fd_files[i].fp != NULL && |
| 2087 | (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { |
| 2088 | struct file *fp; |
| 2089 | |
| 2090 | if (i < fdp->fd_knlistsize) |
| 2091 | knote_fdclose(p, i); |
| 2092 | /* |
| 2093 | * NULL-out descriptor prior to close to avoid |
| 2094 | * a race while close blocks. |
| 2095 | */ |
| 2096 | if ((fp = funsetfd_locked(fdp, i)) != NULL) |
| 2097 | closef(fp, p); |
| 2098 | } |
| 2099 | } |
| 2100 | } |
| 2101 | |
| 2102 | /* |
| 2103 | * It is unsafe for set[ug]id processes to be started with file |
| 2104 | * descriptors 0..2 closed, as these descriptors are given implicit |
| 2105 | * significance in the Standard C library. fdcheckstd() will create a |
| 2106 | * descriptor referencing /dev/null for each of stdin, stdout, and |
| 2107 | * stderr that is not already open. |
| 2108 | * |
| 2109 | * NOT MPSAFE - calls falloc, vn_open, etc |
| 2110 | */ |
| 2111 | int |
| 2112 | fdcheckstd(struct proc *p) |
| 2113 | { |
| 2114 | struct nlookupdata nd; |
| 2115 | struct filedesc *fdp; |
| 2116 | struct file *fp; |
| 2117 | register_t retval; |
| 2118 | int i, error, flags, devnull; |
| 2119 | |
| 2120 | fdp = p->p_fd; |
| 2121 | if (fdp == NULL) |
| 2122 | return (0); |
| 2123 | devnull = -1; |
| 2124 | error = 0; |
| 2125 | for (i = 0; i < 3; i++) { |
| 2126 | if (fdp->fd_files[i].fp != NULL) |
| 2127 | continue; |
| 2128 | if (devnull < 0) { |
| 2129 | if ((error = falloc(p, &fp, &devnull)) != 0) |
| 2130 | break; |
| 2131 | |
| 2132 | error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, |
| 2133 | NLC_FOLLOW|NLC_LOCKVP); |
| 2134 | flags = FREAD | FWRITE; |
| 2135 | if (error == 0) |
| 2136 | error = vn_open(&nd, fp, flags, 0); |
| 2137 | if (error == 0) |
| 2138 | fsetfd(p, fp, devnull); |
| 2139 | else |
| 2140 | fsetfd(p, NULL, devnull); |
| 2141 | fdrop(fp); |
| 2142 | nlookup_done(&nd); |
| 2143 | if (error) |
| 2144 | break; |
| 2145 | KKASSERT(i == devnull); |
| 2146 | } else { |
| 2147 | error = kern_dup(DUP_FIXED, devnull, i, &retval); |
| 2148 | if (error != 0) |
| 2149 | break; |
| 2150 | } |
| 2151 | } |
| 2152 | return (error); |
| 2153 | } |
| 2154 | |
| 2155 | /* |
| 2156 | * Internal form of close. |
| 2157 | * Decrement reference count on file structure. |
| 2158 | * Note: td and/or p may be NULL when closing a file |
| 2159 | * that was being passed in a message. |
| 2160 | * |
| 2161 | * MPALMOSTSAFE - acquires mplock for VOP operations |
| 2162 | */ |
| 2163 | int |
| 2164 | closef(struct file *fp, struct proc *p) |
| 2165 | { |
| 2166 | struct vnode *vp; |
| 2167 | struct flock lf; |
| 2168 | struct filedesc_to_leader *fdtol; |
| 2169 | |
| 2170 | if (fp == NULL) |
| 2171 | return (0); |
| 2172 | |
| 2173 | /* |
| 2174 | * POSIX record locking dictates that any close releases ALL |
| 2175 | * locks owned by this process. This is handled by setting |
| 2176 | * a flag in the unlock to free ONLY locks obeying POSIX |
| 2177 | * semantics, and not to free BSD-style file locks. |
| 2178 | * If the descriptor was in a message, POSIX-style locks |
| 2179 | * aren't passed with the descriptor. |
| 2180 | */ |
| 2181 | if (p != NULL && fp->f_type == DTYPE_VNODE && |
| 2182 | (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) |
| 2183 | ) { |
| 2184 | get_mplock(); |
| 2185 | if ((p->p_leader->p_flag & P_ADVLOCK) != 0) { |
| 2186 | lf.l_whence = SEEK_SET; |
| 2187 | lf.l_start = 0; |
| 2188 | lf.l_len = 0; |
| 2189 | lf.l_type = F_UNLCK; |
| 2190 | vp = (struct vnode *)fp->f_data; |
| 2191 | (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, |
| 2192 | &lf, F_POSIX); |
| 2193 | } |
| 2194 | fdtol = p->p_fdtol; |
| 2195 | if (fdtol != NULL) { |
| 2196 | /* |
| 2197 | * Handle special case where file descriptor table |
| 2198 | * is shared between multiple process leaders. |
| 2199 | */ |
| 2200 | for (fdtol = fdtol->fdl_next; |
| 2201 | fdtol != p->p_fdtol; |
| 2202 | fdtol = fdtol->fdl_next) { |
| 2203 | if ((fdtol->fdl_leader->p_flag & |
| 2204 | P_ADVLOCK) == 0) |
| 2205 | continue; |
| 2206 | fdtol->fdl_holdcount++; |
| 2207 | lf.l_whence = SEEK_SET; |
| 2208 | lf.l_start = 0; |
| 2209 | lf.l_len = 0; |
| 2210 | lf.l_type = F_UNLCK; |
| 2211 | vp = (struct vnode *)fp->f_data; |
| 2212 | (void) VOP_ADVLOCK(vp, |
| 2213 | (caddr_t)fdtol->fdl_leader, |
| 2214 | F_UNLCK, &lf, F_POSIX); |
| 2215 | fdtol->fdl_holdcount--; |
| 2216 | if (fdtol->fdl_holdcount == 0 && |
| 2217 | fdtol->fdl_wakeup != 0) { |
| 2218 | fdtol->fdl_wakeup = 0; |
| 2219 | wakeup(fdtol); |
| 2220 | } |
| 2221 | } |
| 2222 | } |
| 2223 | rel_mplock(); |
| 2224 | } |
| 2225 | return (fdrop(fp)); |
| 2226 | } |
| 2227 | |
| 2228 | /* |
| 2229 | * MPSAFE |
| 2230 | * |
| 2231 | * fhold() can only be called if f_count is already at least 1 (i.e. the |
| 2232 | * caller of fhold() already has a reference to the file pointer in some |
| 2233 | * manner or other). |
| 2234 | * |
| 2235 | * f_count is not spin-locked. Instead, atomic ops are used for |
| 2236 | * incrementing, decrementing, and handling the 1->0 transition. |
| 2237 | */ |
| 2238 | void |
| 2239 | fhold(struct file *fp) |
| 2240 | { |
| 2241 | atomic_add_int(&fp->f_count, 1); |
| 2242 | } |
| 2243 | |
| 2244 | /* |
| 2245 | * fdrop() - drop a reference to a descriptor |
| 2246 | * |
| 2247 | * MPALMOSTSAFE - acquires mplock for final close sequence |
| 2248 | */ |
| 2249 | int |
| 2250 | fdrop(struct file *fp) |
| 2251 | { |
| 2252 | struct flock lf; |
| 2253 | struct vnode *vp; |
| 2254 | int error; |
| 2255 | |
| 2256 | /* |
| 2257 | * A combined fetch and subtract is needed to properly detect |
| 2258 | * 1->0 transitions, otherwise two cpus dropping from a ref |
| 2259 | * count of 2 might both try to run the 1->0 code. |
| 2260 | */ |
| 2261 | if (atomic_fetchadd_int(&fp->f_count, -1) > 1) |
| 2262 | return (0); |
| 2263 | |
| 2264 | get_mplock(); |
| 2265 | |
| 2266 | /* |
| 2267 | * The last reference has gone away, we own the fp structure free |
| 2268 | * and clear. |
| 2269 | */ |
| 2270 | if (fp->f_count < 0) |
| 2271 | panic("fdrop: count < 0"); |
| 2272 | if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && |
| 2273 | (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) |
| 2274 | ) { |
| 2275 | lf.l_whence = SEEK_SET; |
| 2276 | lf.l_start = 0; |
| 2277 | lf.l_len = 0; |
| 2278 | lf.l_type = F_UNLCK; |
| 2279 | vp = (struct vnode *)fp->f_data; |
| 2280 | (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); |
| 2281 | } |
| 2282 | if (fp->f_ops != &badfileops) |
| 2283 | error = fo_close(fp); |
| 2284 | else |
| 2285 | error = 0; |
| 2286 | ffree(fp); |
| 2287 | rel_mplock(); |
| 2288 | return (error); |
| 2289 | } |
| 2290 | |
| 2291 | /* |
| 2292 | * Apply an advisory lock on a file descriptor. |
| 2293 | * |
| 2294 | * Just attempt to get a record lock of the requested type on |
| 2295 | * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). |
| 2296 | */ |
| 2297 | int |
| 2298 | sys_flock(struct flock_args *uap) |
| 2299 | { |
| 2300 | struct proc *p = curproc; |
| 2301 | struct file *fp; |
| 2302 | struct vnode *vp; |
| 2303 | struct flock lf; |
| 2304 | int error; |
| 2305 | |
| 2306 | if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL) |
| 2307 | return (EBADF); |
| 2308 | if (fp->f_type != DTYPE_VNODE) { |
| 2309 | error = EOPNOTSUPP; |
| 2310 | goto done; |
| 2311 | } |
| 2312 | vp = (struct vnode *)fp->f_data; |
| 2313 | lf.l_whence = SEEK_SET; |
| 2314 | lf.l_start = 0; |
| 2315 | lf.l_len = 0; |
| 2316 | if (uap->how & LOCK_UN) { |
| 2317 | lf.l_type = F_UNLCK; |
| 2318 | fp->f_flag &= ~FHASLOCK; |
| 2319 | error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); |
| 2320 | goto done; |
| 2321 | } |
| 2322 | if (uap->how & LOCK_EX) |
| 2323 | lf.l_type = F_WRLCK; |
| 2324 | else if (uap->how & LOCK_SH) |
| 2325 | lf.l_type = F_RDLCK; |
| 2326 | else { |
| 2327 | error = EBADF; |
| 2328 | goto done; |
| 2329 | } |
| 2330 | fp->f_flag |= FHASLOCK; |
| 2331 | if (uap->how & LOCK_NB) |
| 2332 | error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); |
| 2333 | else |
| 2334 | error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); |
| 2335 | done: |
| 2336 | fdrop(fp); |
| 2337 | return (error); |
| 2338 | } |
| 2339 | |
| 2340 | /* |
| 2341 | * File Descriptor pseudo-device driver (/dev/fd/). |
| 2342 | * |
| 2343 | * Opening minor device N dup()s the file (if any) connected to file |
| 2344 | * descriptor N belonging to the calling process. Note that this driver |
| 2345 | * consists of only the ``open()'' routine, because all subsequent |
| 2346 | * references to this file will be direct to the other driver. |
| 2347 | */ |
| 2348 | /* ARGSUSED */ |
| 2349 | static int |
| 2350 | fdopen(struct dev_open_args *ap) |
| 2351 | { |
| 2352 | thread_t td = curthread; |
| 2353 | |
| 2354 | KKASSERT(td->td_lwp != NULL); |
| 2355 | |
| 2356 | /* |
| 2357 | * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the |
| 2358 | * the file descriptor being sought for duplication. The error |
| 2359 | * return ensures that the vnode for this device will be released |
| 2360 | * by vn_open. Open will detect this special error and take the |
| 2361 | * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN |
| 2362 | * will simply report the error. |
| 2363 | */ |
| 2364 | td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev); |
| 2365 | return (ENODEV); |
| 2366 | } |
| 2367 | |
| 2368 | /* |
| 2369 | * The caller has reserved the file descriptor dfd for us. On success we |
| 2370 | * must fsetfd() it. On failure the caller will clean it up. |
| 2371 | * |
| 2372 | * NOT MPSAFE - isn't getting spinlocks, possibly other things |
| 2373 | */ |
| 2374 | int |
| 2375 | dupfdopen(struct proc *p, int dfd, int sfd, int mode, int error) |
| 2376 | { |
| 2377 | struct filedesc *fdp = p->p_fd; |
| 2378 | struct file *wfp; |
| 2379 | struct file *xfp; |
| 2380 | int werror; |
| 2381 | |
| 2382 | if ((wfp = holdfp(fdp, sfd, -1)) == NULL) |
| 2383 | return (EBADF); |
| 2384 | |
| 2385 | /* |
| 2386 | * Close a revoke/dup race. Duping a descriptor marked as revoked |
| 2387 | * will dup a dummy descriptor instead of the real one. |
| 2388 | */ |
| 2389 | if (wfp->f_flag & FREVOKED) { |
| 2390 | kprintf("Warning: attempt to dup() a revoked descriptor\n"); |
| 2391 | fdrop(wfp); |
| 2392 | wfp = NULL; |
| 2393 | werror = falloc(NULL, &wfp, NULL); |
| 2394 | if (werror) |
| 2395 | return (werror); |
| 2396 | } |
| 2397 | |
| 2398 | /* |
| 2399 | * There are two cases of interest here. |
| 2400 | * |
| 2401 | * For ENODEV simply dup sfd to file descriptor dfd and return. |
| 2402 | * |
| 2403 | * For ENXIO steal away the file structure from sfd and store it |
| 2404 | * dfd. sfd is effectively closed by this operation. |
| 2405 | * |
| 2406 | * Any other error code is just returned. |
| 2407 | */ |
| 2408 | switch (error) { |
| 2409 | case ENODEV: |
| 2410 | /* |
| 2411 | * Check that the mode the file is being opened for is a |
| 2412 | * subset of the mode of the existing descriptor. |
| 2413 | */ |
| 2414 | if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { |
| 2415 | error = EACCES; |
| 2416 | break; |
| 2417 | } |
| 2418 | fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; |
| 2419 | fsetfd(p, wfp, dfd); |
| 2420 | error = 0; |
| 2421 | break; |
| 2422 | case ENXIO: |
| 2423 | /* |
| 2424 | * Steal away the file pointer from dfd, and stuff it into indx. |
| 2425 | */ |
| 2426 | fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags; |
| 2427 | fsetfd(p, wfp, dfd); |
| 2428 | if ((xfp = funsetfd_locked(fdp, sfd)) != NULL) |
| 2429 | fdrop(xfp); |
| 2430 | error = 0; |
| 2431 | break; |
| 2432 | default: |
| 2433 | break; |
| 2434 | } |
| 2435 | fdrop(wfp); |
| 2436 | return (error); |
| 2437 | } |
| 2438 | |
| 2439 | /* |
| 2440 | * NOT MPSAFE - I think these refer to a common file descriptor table |
| 2441 | * and we need to spinlock that to link fdtol in. |
| 2442 | */ |
| 2443 | struct filedesc_to_leader * |
| 2444 | filedesc_to_leader_alloc(struct filedesc_to_leader *old, |
| 2445 | struct proc *leader) |
| 2446 | { |
| 2447 | struct filedesc_to_leader *fdtol; |
| 2448 | |
| 2449 | fdtol = kmalloc(sizeof(struct filedesc_to_leader), |
| 2450 | M_FILEDESC_TO_LEADER, M_WAITOK); |
| 2451 | fdtol->fdl_refcount = 1; |
| 2452 | fdtol->fdl_holdcount = 0; |
| 2453 | fdtol->fdl_wakeup = 0; |
| 2454 | fdtol->fdl_leader = leader; |
| 2455 | if (old != NULL) { |
| 2456 | fdtol->fdl_next = old->fdl_next; |
| 2457 | fdtol->fdl_prev = old; |
| 2458 | old->fdl_next = fdtol; |
| 2459 | fdtol->fdl_next->fdl_prev = fdtol; |
| 2460 | } else { |
| 2461 | fdtol->fdl_next = fdtol; |
| 2462 | fdtol->fdl_prev = fdtol; |
| 2463 | } |
| 2464 | return fdtol; |
| 2465 | } |
| 2466 | |
| 2467 | /* |
| 2468 | * Scan all file pointers in the system. The callback is made with |
| 2469 | * the master list spinlock held exclusively. |
| 2470 | * |
| 2471 | * MPSAFE |
| 2472 | */ |
| 2473 | void |
| 2474 | allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) |
| 2475 | { |
| 2476 | struct file *fp; |
| 2477 | int res; |
| 2478 | |
| 2479 | spin_lock_wr(&filehead_spin); |
| 2480 | LIST_FOREACH(fp, &filehead, f_list) { |
| 2481 | res = callback(fp, data); |
| 2482 | if (res < 0) |
| 2483 | break; |
| 2484 | } |
| 2485 | spin_unlock_wr(&filehead_spin); |
| 2486 | } |
| 2487 | |
| 2488 | /* |
| 2489 | * Get file structures. |
| 2490 | * |
| 2491 | * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) |
| 2492 | */ |
| 2493 | |
| 2494 | struct sysctl_kern_file_info { |
| 2495 | int count; |
| 2496 | int error; |
| 2497 | struct sysctl_req *req; |
| 2498 | }; |
| 2499 | |
| 2500 | static int sysctl_kern_file_callback(struct proc *p, void *data); |
| 2501 | |
| 2502 | static int |
| 2503 | sysctl_kern_file(SYSCTL_HANDLER_ARGS) |
| 2504 | { |
| 2505 | struct sysctl_kern_file_info info; |
| 2506 | |
| 2507 | /* |
| 2508 | * Note: because the number of file descriptors is calculated |
| 2509 | * in different ways for sizing vs returning the data, |
| 2510 | * there is information leakage from the first loop. However, |
| 2511 | * it is of a similar order of magnitude to the leakage from |
| 2512 | * global system statistics such as kern.openfiles. |
| 2513 | * |
| 2514 | * When just doing a count, note that we cannot just count |
| 2515 | * the elements and add f_count via the filehead list because |
| 2516 | * threaded processes share their descriptor table and f_count might |
| 2517 | * still be '1' in that case. |
| 2518 | * |
| 2519 | * Since the SYSCTL op can block, we must hold the process to |
| 2520 | * prevent it being ripped out from under us either in the |
| 2521 | * file descriptor loop or in the greater LIST_FOREACH. The |
| 2522 | * process may be in varying states of disrepair. If the process |
| 2523 | * is in SZOMB we may have caught it just as it is being removed |
| 2524 | * from the allproc list, we must skip it in that case to maintain |
| 2525 | * an unbroken chain through the allproc list. |
| 2526 | */ |
| 2527 | info.count = 0; |
| 2528 | info.error = 0; |
| 2529 | info.req = req; |
| 2530 | allproc_scan(sysctl_kern_file_callback, &info); |
| 2531 | |
| 2532 | /* |
| 2533 | * When just calculating the size, overestimate a bit to try to |
| 2534 | * prevent system activity from causing the buffer-fill call |
| 2535 | * to fail later on. |
| 2536 | */ |
| 2537 | if (req->oldptr == NULL) { |
| 2538 | info.count = (info.count + 16) + (info.count / 10); |
| 2539 | info.error = SYSCTL_OUT(req, NULL, |
| 2540 | info.count * sizeof(struct kinfo_file)); |
| 2541 | } |
| 2542 | return (info.error); |
| 2543 | } |
| 2544 | |
| 2545 | static int |
| 2546 | sysctl_kern_file_callback(struct proc *p, void *data) |
| 2547 | { |
| 2548 | struct sysctl_kern_file_info *info = data; |
| 2549 | struct kinfo_file kf; |
| 2550 | struct filedesc *fdp; |
| 2551 | struct file *fp; |
| 2552 | uid_t uid; |
| 2553 | int n; |
| 2554 | |
| 2555 | if (p->p_stat == SIDL || p->p_stat == SZOMB) |
| 2556 | return(0); |
| 2557 | if (!PRISON_CHECK(info->req->td->td_proc->p_ucred, p->p_ucred) != 0) |
| 2558 | return(0); |
| 2559 | if ((fdp = p->p_fd) == NULL) |
| 2560 | return(0); |
| 2561 | spin_lock_rd(&fdp->fd_spin); |
| 2562 | for (n = 0; n < fdp->fd_nfiles; ++n) { |
| 2563 | if ((fp = fdp->fd_files[n].fp) == NULL) |
| 2564 | continue; |
| 2565 | if (info->req->oldptr == NULL) { |
| 2566 | ++info->count; |
| 2567 | } else { |
| 2568 | uid = p->p_ucred ? p->p_ucred->cr_uid : -1; |
| 2569 | kcore_make_file(&kf, fp, p->p_pid, uid, n); |
| 2570 | spin_unlock_rd(&fdp->fd_spin); |
| 2571 | info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); |
| 2572 | spin_lock_rd(&fdp->fd_spin); |
| 2573 | if (info->error) |
| 2574 | break; |
| 2575 | } |
| 2576 | } |
| 2577 | spin_unlock_rd(&fdp->fd_spin); |
| 2578 | if (info->error) |
| 2579 | return(-1); |
| 2580 | return(0); |
| 2581 | } |
| 2582 | |
| 2583 | SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, |
| 2584 | 0, 0, sysctl_kern_file, "S,file", "Entire file table"); |
| 2585 | |
| 2586 | SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, |
| 2587 | &maxfilesperproc, 0, "Maximum files allowed open per process"); |
| 2588 | |
| 2589 | SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, |
| 2590 | &maxfiles, 0, "Maximum number of files"); |
| 2591 | |
| 2592 | SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, |
| 2593 | &maxfilesrootres, 0, "Descriptors reserved for root use"); |
| 2594 | |
| 2595 | SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, |
| 2596 | &nfiles, 0, "System-wide number of open files"); |
| 2597 | |
| 2598 | static void |
| 2599 | fildesc_drvinit(void *unused) |
| 2600 | { |
| 2601 | int fd; |
| 2602 | |
| 2603 | dev_ops_add(&fildesc_ops, 0, 0); |
| 2604 | for (fd = 0; fd < NUMFDESC; fd++) { |
| 2605 | make_dev(&fildesc_ops, fd, |
| 2606 | UID_BIN, GID_BIN, 0666, "fd/%d", fd); |
| 2607 | } |
| 2608 | make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); |
| 2609 | make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); |
| 2610 | make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); |
| 2611 | } |
| 2612 | |
| 2613 | /* |
| 2614 | * MPSAFE |
| 2615 | */ |
| 2616 | struct fileops badfileops = { |
| 2617 | .fo_read = badfo_readwrite, |
| 2618 | .fo_write = badfo_readwrite, |
| 2619 | .fo_ioctl = badfo_ioctl, |
| 2620 | .fo_poll = badfo_poll, |
| 2621 | .fo_kqfilter = badfo_kqfilter, |
| 2622 | .fo_stat = badfo_stat, |
| 2623 | .fo_close = badfo_close, |
| 2624 | .fo_shutdown = badfo_shutdown |
| 2625 | }; |
| 2626 | |
| 2627 | /* |
| 2628 | * MPSAFE |
| 2629 | */ |
| 2630 | static int |
| 2631 | badfo_readwrite( |
| 2632 | struct file *fp, |
| 2633 | struct uio *uio, |
| 2634 | struct ucred *cred, |
| 2635 | int flags |
| 2636 | ) { |
| 2637 | return (EBADF); |
| 2638 | } |
| 2639 | |
| 2640 | /* |
| 2641 | * MPSAFE |
| 2642 | */ |
| 2643 | static int |
| 2644 | badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *cred) |
| 2645 | { |
| 2646 | return (EBADF); |
| 2647 | } |
| 2648 | |
| 2649 | /* |
| 2650 | * MPSAFE |
| 2651 | */ |
| 2652 | static int |
| 2653 | badfo_poll(struct file *fp, int events, struct ucred *cred) |
| 2654 | { |
| 2655 | return (0); |
| 2656 | } |
| 2657 | |
| 2658 | /* |
| 2659 | * MPSAFE |
| 2660 | */ |
| 2661 | static int |
| 2662 | badfo_kqfilter(struct file *fp, struct knote *kn) |
| 2663 | { |
| 2664 | return (0); |
| 2665 | } |
| 2666 | |
| 2667 | static int |
| 2668 | badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) |
| 2669 | { |
| 2670 | return (EBADF); |
| 2671 | } |
| 2672 | |
| 2673 | /* |
| 2674 | * MPSAFE |
| 2675 | */ |
| 2676 | static int |
| 2677 | badfo_close(struct file *fp) |
| 2678 | { |
| 2679 | return (EBADF); |
| 2680 | } |
| 2681 | |
| 2682 | /* |
| 2683 | * MPSAFE |
| 2684 | */ |
| 2685 | static int |
| 2686 | badfo_shutdown(struct file *fp, int how) |
| 2687 | { |
| 2688 | return (EBADF); |
| 2689 | } |
| 2690 | |
| 2691 | /* |
| 2692 | * MPSAFE |
| 2693 | */ |
| 2694 | int |
| 2695 | nofo_shutdown(struct file *fp, int how) |
| 2696 | { |
| 2697 | return (EOPNOTSUPP); |
| 2698 | } |
| 2699 | |
| 2700 | SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, |
| 2701 | fildesc_drvinit,NULL) |