frevoke - More fixes to fdfree()
[dragonfly.git] / sys / kern / kern_descrip.c
CommitLineData
984263bc 1/*
29d211fb
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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 *
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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
c4cb6d8b 72 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $
8f9f2535 73 * $DragonFly: src/sys/kern/kern_descrip.c,v 1.79 2008/08/31 13:18:28 aggelos Exp $
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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>
fef8985e 82#include <sys/device.h>
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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>
fad57d0e 88#include <sys/nlookup.h>
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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>
dda4b42b 96#include <sys/kern_syscall.h>
1c55bd1c 97#include <sys/kcore.h>
7b124c9f 98#include <sys/kinfo.h>
ea8f324c 99#include <sys/un.h>
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100
101#include <vm/vm.h>
102#include <vm/vm_extern.h>
103
e43a034f 104#include <sys/thread2.h>
dadab5e9 105#include <sys/file2.h>
85fceac1 106#include <sys/spinlock2.h>
dadab5e9 107
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108static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd);
109static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr);
110static struct file *funsetfd_locked (struct filedesc *fdp, int fd);
85fceac1 111static int checkfpclosed(struct filedesc *fdp, int fd, struct file *fp);
5b287bba 112static void ffree(struct file *fp);
fa541be6 113
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114static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
115static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader",
116 "file desc to leader structures");
117MALLOC_DEFINE(M_FILE, "file", "Open file structure");
118static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
119
120static d_open_t fdopen;
121#define NUMFDESC 64
122
123#define CDEV_MAJOR 22
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124static struct dev_ops fildesc_ops = {
125 { "FD", CDEV_MAJOR, 0 },
126 .d_open = fdopen,
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127};
128
402ed7e1 129static int badfo_readwrite (struct file *fp, struct uio *uio,
87de5057 130 struct ucred *cred, int flags);
402ed7e1 131static int badfo_ioctl (struct file *fp, u_long com, caddr_t data,
87de5057
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132 struct ucred *cred);
133static int badfo_poll (struct file *fp, int events, struct ucred *cred);
402ed7e1 134static int badfo_kqfilter (struct file *fp, struct knote *kn);
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MD
135static int badfo_stat (struct file *fp, struct stat *sb, struct ucred *cred);
136static int badfo_close (struct file *fp);
137static int badfo_shutdown (struct file *fp, int how);
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138
139/*
140 * Descriptor management.
141 */
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142static struct filelist filehead = LIST_HEAD_INITIALIZER(&filehead);
143static struct spinlock filehead_spin = SPINLOCK_INITIALIZER(&filehead_spin);
144static int nfiles; /* actual number of open files */
984263bc
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145extern int cmask;
146
8247b2f9
MD
147/*
148 * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared.
5b287bba
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149 *
150 * MPSAFE - must be called with fdp->fd_spin exclusively held
8247b2f9
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151 */
152static __inline
153void
5b287bba 154fdfixup_locked(struct filedesc *fdp, int fd)
8247b2f9
MD
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
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167/*
168 * System calls on descriptors.
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169 *
170 * MPSAFE
984263bc 171 */
984263bc 172int
753fd850 173sys_getdtablesize(struct getdtablesize_args *uap)
984263bc 174{
41c20dac 175 struct proc *p = curproc;
5b287bba 176 struct plimit *limit = p->p_limit;
984263bc 177
5b287bba 178 spin_lock_rd(&limit->p_spin);
c7114eea 179 uap->sysmsg_result =
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180 min((int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
181 spin_unlock_rd(&limit->p_spin);
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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).
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190 *
191 * MPSAFE
984263bc 192 */
984263bc 193int
753fd850 194sys_dup2(struct dup2_args *uap)
984263bc 195{
dda4b42b 196 int error;
973c11b9 197 int fd = 0;
dda4b42b 198
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MD
199 error = kern_dup(DUP_FIXED, uap->from, uap->to, &fd);
200 uap->sysmsg_fds[0] = fd;
dda4b42b
DRJ
201
202 return (error);
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203}
204
205/*
206 * Duplicate a file descriptor.
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207 *
208 * MPSAFE
984263bc 209 */
984263bc 210int
753fd850 211sys_dup(struct dup_args *uap)
984263bc 212{
dda4b42b 213 int error;
973c11b9 214 int fd = 0;
984263bc 215
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216 error = kern_dup(DUP_VARIABLE, uap->fd, 0, &fd);
217 uap->sysmsg_fds[0] = fd;
dda4b42b
DRJ
218
219 return (error);
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220}
221
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222/*
223 * MPALMOSTSAFE - acquires mplock for fp operations
224 */
984263bc 225int
87de5057 226kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred)
984263bc 227{
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228 struct thread *td = curthread;
229 struct proc *p = td->td_proc;
41c20dac 230 struct file *fp;
984263bc 231 struct vnode *vp;
984263bc 232 u_int newmin;
9ba76b73 233 u_int oflags;
3a907475 234 u_int nflags;
dda4b42b 235 int tmp, error, flg = F_POSIX;
984263bc 236
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237 KKASSERT(p);
238
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239 /*
240 * Operations on file descriptors that do not require a file pointer.
241 */
dda4b42b 242 switch (cmd) {
984263bc 243 case F_GETFD:
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MD
244 error = fgetfdflags(p->p_fd, fd, &tmp);
245 if (error == 0)
246 dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0;
5b287bba 247 return (error);
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248
249 case F_SETFD:
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250 if (dat->fc_cloexec & FD_CLOEXEC)
251 error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE);
252 else
253 error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE);
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MD
254 return (error);
255 case F_DUPFD:
256 newmin = dat->fc_fd;
257 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd);
258 return (error);
259 default:
85fceac1 260 break;
5b287bba 261 }
984263bc 262
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MD
263 /*
264 * Operations on file pointers
265 */
266 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL)
267 return (EBADF);
268
269 get_mplock();
270 switch (cmd) {
984263bc 271 case F_GETFL:
dda4b42b 272 dat->fc_flags = OFLAGS(fp->f_flag);
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273 error = 0;
274 break;
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275
276 case F_SETFL:
3a907475
MD
277 oflags = fp->f_flag;
278 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS;
279 nflags |= oflags & ~FCNTLFLAGS;
280
f58b505b 281 error = 0;
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282 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY))
283 error = EINVAL;
284 if (error == 0 && ((nflags ^ oflags) & FASYNC)) {
e8cdd284 285 tmp = nflags & FASYNC;
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MD
286 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, cred);
287 }
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MD
288 if (error == 0)
289 fp->f_flag = nflags;
85fceac1 290 break;
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291
292 case F_GETOWN:
87de5057 293 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, cred);
85fceac1 294 break;
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MD
295
296 case F_SETOWN:
87de5057 297 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, cred);
85fceac1 298 break;
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299
300 case F_SETLKW:
301 flg |= F_WAIT;
302 /* Fall into F_SETLK */
303
304 case F_SETLK:
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305 if (fp->f_type != DTYPE_VNODE) {
306 error = EBADF;
307 break;
308 }
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MD
309 vp = (struct vnode *)fp->f_data;
310
311 /*
312 * copyin/lockop may block
313 */
dda4b42b
DRJ
314 if (dat->fc_flock.l_whence == SEEK_CUR)
315 dat->fc_flock.l_start += fp->f_offset;
984263bc 316
dda4b42b 317 switch (dat->fc_flock.l_type) {
984263bc
MD
318 case F_RDLCK:
319 if ((fp->f_flag & FREAD) == 0) {
320 error = EBADF;
321 break;
322 }
323 p->p_leader->p_flag |= P_ADVLOCK;
324 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
dda4b42b 325 &dat->fc_flock, flg);
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MD
326 break;
327 case F_WRLCK:
328 if ((fp->f_flag & FWRITE) == 0) {
329 error = EBADF;
330 break;
331 }
332 p->p_leader->p_flag |= P_ADVLOCK;
333 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
dda4b42b 334 &dat->fc_flock, flg);
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MD
335 break;
336 case F_UNLCK:
337 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
dda4b42b 338 &dat->fc_flock, F_POSIX);
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MD
339 break;
340 default:
341 error = EINVAL;
342 break;
343 }
85fceac1
MD
344
345 /*
346 * It is possible to race a close() on the descriptor while
347 * we were blocked getting the lock. If this occurs the
348 * close might not have caught the lock.
349 */
350 if (checkfpclosed(p->p_fd, fd, fp)) {
dda4b42b
DRJ
351 dat->fc_flock.l_whence = SEEK_SET;
352 dat->fc_flock.l_start = 0;
353 dat->fc_flock.l_len = 0;
354 dat->fc_flock.l_type = F_UNLCK;
984263bc 355 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
dda4b42b 356 F_UNLCK, &dat->fc_flock, F_POSIX);
984263bc 357 }
85fceac1 358 break;
984263bc
MD
359
360 case F_GETLK:
85fceac1
MD
361 if (fp->f_type != DTYPE_VNODE) {
362 error = EBADF;
363 break;
364 }
984263bc
MD
365 vp = (struct vnode *)fp->f_data;
366 /*
367 * copyin/lockop may block
368 */
dda4b42b
DRJ
369 if (dat->fc_flock.l_type != F_RDLCK &&
370 dat->fc_flock.l_type != F_WRLCK &&
371 dat->fc_flock.l_type != F_UNLCK) {
85fceac1
MD
372 error = EINVAL;
373 break;
984263bc 374 }
dda4b42b
DRJ
375 if (dat->fc_flock.l_whence == SEEK_CUR)
376 dat->fc_flock.l_start += fp->f_offset;
984263bc 377 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
dda4b42b 378 &dat->fc_flock, F_POSIX);
85fceac1 379 break;
984263bc 380 default:
85fceac1
MD
381 error = EINVAL;
382 break;
984263bc 383 }
5b287bba
MD
384 rel_mplock();
385
85fceac1
MD
386 fdrop(fp);
387 return (error);
984263bc
MD
388}
389
dda4b42b
DRJ
390/*
391 * The file control system call.
5b287bba
MD
392 *
393 * MPSAFE
dda4b42b
DRJ
394 */
395int
753fd850 396sys_fcntl(struct fcntl_args *uap)
dda4b42b
DRJ
397{
398 union fcntl_dat dat;
399 int error;
400
401 switch (uap->cmd) {
402 case F_DUPFD:
403 dat.fc_fd = uap->arg;
404 break;
405 case F_SETFD:
406 dat.fc_cloexec = uap->arg;
407 break;
408 case F_SETFL:
409 dat.fc_flags = uap->arg;
410 break;
411 case F_SETOWN:
412 dat.fc_owner = uap->arg;
413 break;
414 case F_SETLKW:
415 case F_SETLK:
416 case F_GETLK:
417 error = copyin((caddr_t)uap->arg, &dat.fc_flock,
5b287bba 418 sizeof(struct flock));
dda4b42b
DRJ
419 if (error)
420 return (error);
421 break;
422 }
423
87de5057 424 error = kern_fcntl(uap->fd, uap->cmd, &dat, curproc->p_ucred);
dda4b42b
DRJ
425
426 if (error == 0) {
427 switch (uap->cmd) {
428 case F_DUPFD:
429 uap->sysmsg_result = dat.fc_fd;
430 break;
431 case F_GETFD:
432 uap->sysmsg_result = dat.fc_cloexec;
433 break;
434 case F_GETFL:
435 uap->sysmsg_result = dat.fc_flags;
436 break;
437 case F_GETOWN:
438 uap->sysmsg_result = dat.fc_owner;
439 case F_GETLK:
440 error = copyout(&dat.fc_flock, (caddr_t)uap->arg,
441 sizeof(struct flock));
442 break;
443 }
444 }
445
446 return (error);
447}
448
984263bc
MD
449/*
450 * Common code for dup, dup2, and fcntl(F_DUPFD).
dda4b42b
DRJ
451 *
452 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells
453 * kern_dup() to destructively dup over an existing file descriptor if new
454 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest
455 * unused file descriptor that is greater than or equal to new.
5b287bba
MD
456 *
457 * MPSAFE
984263bc 458 */
dda4b42b
DRJ
459int
460kern_dup(enum dup_type type, int old, int new, int *res)
984263bc 461{
dda4b42b
DRJ
462 struct thread *td = curthread;
463 struct proc *p = td->td_proc;
464 struct filedesc *fdp = p->p_fd;
984263bc
MD
465 struct file *fp;
466 struct file *delfp;
259b8ea0 467 int oldflags;
984263bc 468 int holdleaders;
dda4b42b
DRJ
469 int error, newfd;
470
471 /*
472 * Verify that we have a valid descriptor to dup from and
473 * possibly to dup to.
474 */
259b8ea0 475retry:
5b287bba
MD
476 spin_lock_wr(&fdp->fd_spin);
477 if (new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
478 new >= maxfilesperproc) {
479 spin_unlock_wr(&fdp->fd_spin);
480 return (EINVAL);
481 }
482 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) {
483 spin_unlock_wr(&fdp->fd_spin);
dda4b42b 484 return (EBADF);
5b287bba 485 }
dda4b42b
DRJ
486 if (type == DUP_FIXED && old == new) {
487 *res = new;
5b287bba 488 spin_unlock_wr(&fdp->fd_spin);
dda4b42b
DRJ
489 return (0);
490 }
0679adc4 491 fp = fdp->fd_files[old].fp;
259b8ea0 492 oldflags = fdp->fd_files[old].fileflags;
5b287bba 493 fhold(fp); /* MPSAFE - can be called with a spinlock held */
dda4b42b
DRJ
494
495 /*
259b8ea0
MD
496 * Allocate a new descriptor if DUP_VARIABLE, or expand the table
497 * if the requested descriptor is beyond the current table size.
498 *
499 * This can block. Retry if the source descriptor no longer matches
500 * or if our expectation in the expansion case races.
501 *
502 * If we are not expanding or allocating a new decriptor, then reset
503 * the target descriptor to a reserved state so we have a uniform
504 * setup for the next code block.
dda4b42b
DRJ
505 */
506 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) {
5b287bba 507 spin_unlock_wr(&fdp->fd_spin);
dda4b42b 508 error = fdalloc(p, new, &newfd);
5b287bba 509 spin_lock_wr(&fdp->fd_spin);
dda4b42b 510 if (error) {
5b287bba 511 spin_unlock_wr(&fdp->fd_spin);
9f87144f 512 fdrop(fp);
dda4b42b
DRJ
513 return (error);
514 }
5b287bba
MD
515 /*
516 * Check for ripout
517 */
259b8ea0 518 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) {
5b287bba
MD
519 fsetfd_locked(fdp, NULL, newfd);
520 spin_unlock_wr(&fdp->fd_spin);
259b8ea0
MD
521 fdrop(fp);
522 goto retry;
523 }
5b287bba
MD
524 /*
525 * Check for expansion race
526 */
259b8ea0 527 if (type != DUP_VARIABLE && new != newfd) {
5b287bba
MD
528 fsetfd_locked(fdp, NULL, newfd);
529 spin_unlock_wr(&fdp->fd_spin);
259b8ea0
MD
530 fdrop(fp);
531 goto retry;
532 }
5b287bba
MD
533 /*
534 * Check for ripout, newfd reused old (this case probably
535 * can't occur).
536 */
259b8ea0 537 if (old == newfd) {
5b287bba
MD
538 fsetfd_locked(fdp, NULL, newfd);
539 spin_unlock_wr(&fdp->fd_spin);
259b8ea0
MD
540 fdrop(fp);
541 goto retry;
542 }
dda4b42b 543 new = newfd;
259b8ea0
MD
544 delfp = NULL;
545 } else {
546 if (fdp->fd_files[new].reserved) {
5b287bba 547 spin_unlock_wr(&fdp->fd_spin);
259b8ea0 548 fdrop(fp);
6ea70f76 549 kprintf("Warning: dup(): target descriptor %d is reserved, waiting for it to be resolved\n", new);
259b8ea0
MD
550 tsleep(fdp, 0, "fdres", hz);
551 goto retry;
552 }
dda4b42b 553
259b8ea0
MD
554 /*
555 * If the target descriptor was never allocated we have
556 * to allocate it. If it was we have to clean out the
5b287bba
MD
557 * old descriptor. delfp inherits the ref from the
558 * descriptor table.
259b8ea0
MD
559 */
560 delfp = fdp->fd_files[new].fp;
561 fdp->fd_files[new].fp = NULL;
562 fdp->fd_files[new].reserved = 1;
563 if (delfp == NULL) {
5b287bba 564 fdreserve_locked(fdp, new, 1);
259b8ea0
MD
565 if (new > fdp->fd_lastfile)
566 fdp->fd_lastfile = new;
dda4b42b 567 }
259b8ea0 568
dda4b42b 569 }
984263bc 570
5b287bba
MD
571 /*
572 * NOTE: still holding an exclusive spinlock
573 */
574
984263bc 575 /*
259b8ea0
MD
576 * If a descriptor is being overwritten we may hve to tell
577 * fdfree() to sleep to ensure that all relevant process
578 * leaders can be traversed in closef().
984263bc 579 */
984263bc 580 if (delfp != NULL && p->p_fdtol != NULL) {
984263bc
MD
581 fdp->fd_holdleaderscount++;
582 holdleaders = 1;
259b8ea0 583 } else {
984263bc 584 holdleaders = 0;
259b8ea0 585 }
dda4b42b 586 KASSERT(delfp == NULL || type == DUP_FIXED,
259b8ea0 587 ("dup() picked an open file"));
984263bc
MD
588
589 /*
259b8ea0
MD
590 * Duplicate the source descriptor, update lastfile. If the new
591 * descriptor was not allocated and we aren't replacing an existing
592 * descriptor we have to mark the descriptor as being in use.
593 *
594 * The fd_files[] array inherits fp's hold reference.
984263bc 595 */
5b287bba 596 fsetfd_locked(fdp, fp, new);
259b8ea0 597 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE;
5b287bba
MD
598 spin_unlock_wr(&fdp->fd_spin);
599 fdrop(fp);
dda4b42b 600 *res = new;
984263bc
MD
601
602 /*
603 * If we dup'd over a valid file, we now own the reference to it
604 * and must dispose of it using closef() semantics (as if a
605 * close() were performed on it).
606 */
607 if (delfp) {
b8477cda 608 closef(delfp, p);
984263bc 609 if (holdleaders) {
5b287bba 610 spin_lock_wr(&fdp->fd_spin);
984263bc
MD
611 fdp->fd_holdleaderscount--;
612 if (fdp->fd_holdleaderscount == 0 &&
613 fdp->fd_holdleaderswakeup != 0) {
614 fdp->fd_holdleaderswakeup = 0;
5b287bba 615 spin_unlock_wr(&fdp->fd_spin);
984263bc 616 wakeup(&fdp->fd_holdleaderscount);
5b287bba
MD
617 } else {
618 spin_unlock_wr(&fdp->fd_spin);
984263bc
MD
619 }
620 }
621 }
622 return (0);
623}
624
625/*
626 * If sigio is on the list associated with a process or process group,
627 * disable signalling from the device, remove sigio from the list and
628 * free sigio.
629 */
630void
7bf8660a 631funsetown(struct sigio *sigio)
984263bc 632{
984263bc
MD
633 if (sigio == NULL)
634 return;
e43a034f 635 crit_enter();
984263bc 636 *(sigio->sio_myref) = NULL;
e43a034f 637 crit_exit();
984263bc
MD
638 if (sigio->sio_pgid < 0) {
639 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
640 sigio, sio_pgsigio);
641 } else /* if ((*sigiop)->sio_pgid > 0) */ {
642 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
643 sigio, sio_pgsigio);
644 }
645 crfree(sigio->sio_ucred);
efda3bd0 646 kfree(sigio, M_SIGIO);
984263bc
MD
647}
648
649/* Free a list of sigio structures. */
650void
7bf8660a 651funsetownlst(struct sigiolst *sigiolst)
984263bc
MD
652{
653 struct sigio *sigio;
654
655 while ((sigio = SLIST_FIRST(sigiolst)) != NULL)
656 funsetown(sigio);
657}
658
659/*
660 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
661 *
662 * After permission checking, add a sigio structure to the sigio list for
663 * the process or process group.
664 */
665int
7bf8660a 666fsetown(pid_t pgid, struct sigio **sigiop)
984263bc
MD
667{
668 struct proc *proc;
669 struct pgrp *pgrp;
670 struct sigio *sigio;
984263bc
MD
671
672 if (pgid == 0) {
673 funsetown(*sigiop);
674 return (0);
675 }
676 if (pgid > 0) {
677 proc = pfind(pgid);
678 if (proc == NULL)
679 return (ESRCH);
680
681 /*
682 * Policy - Don't allow a process to FSETOWN a process
683 * in another session.
684 *
685 * Remove this test to allow maximum flexibility or
686 * restrict FSETOWN to the current process or process
687 * group for maximum safety.
688 */
689 if (proc->p_session != curproc->p_session)
690 return (EPERM);
691
692 pgrp = NULL;
693 } else /* if (pgid < 0) */ {
694 pgrp = pgfind(-pgid);
695 if (pgrp == NULL)
696 return (ESRCH);
697
698 /*
699 * Policy - Don't allow a process to FSETOWN a process
700 * in another session.
701 *
702 * Remove this test to allow maximum flexibility or
703 * restrict FSETOWN to the current process or process
704 * group for maximum safety.
705 */
706 if (pgrp->pg_session != curproc->p_session)
707 return (EPERM);
708
709 proc = NULL;
710 }
711 funsetown(*sigiop);
efda3bd0 712 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK);
984263bc
MD
713 if (pgid > 0) {
714 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
715 sigio->sio_proc = proc;
716 } else {
717 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
718 sigio->sio_pgrp = pgrp;
719 }
720 sigio->sio_pgid = pgid;
e9a372eb 721 sigio->sio_ucred = crhold(curproc->p_ucred);
984263bc 722 /* It would be convenient if p_ruid was in ucred. */
41c20dac 723 sigio->sio_ruid = curproc->p_ucred->cr_ruid;
984263bc 724 sigio->sio_myref = sigiop;
e43a034f 725 crit_enter();
984263bc 726 *sigiop = sigio;
e43a034f 727 crit_exit();
984263bc
MD
728 return (0);
729}
730
731/*
732 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
733 */
734pid_t
7bf8660a 735fgetown(struct sigio *sigio)
984263bc
MD
736{
737 return (sigio != NULL ? sigio->sio_pgid : 0);
738}
739
4336d5df
JS
740/*
741 * Close many file descriptors.
5b287bba
MD
742 *
743 * MPSAFE
4336d5df 744 */
4336d5df 745int
753fd850 746sys_closefrom(struct closefrom_args *uap)
4336d5df
JS
747{
748 return(kern_closefrom(uap->fd));
749}
750
5b287bba
MD
751/*
752 * Close all file descriptors greater then or equal to fd
753 *
754 * MPSAFE
755 */
4336d5df
JS
756int
757kern_closefrom(int fd)
758{
759 struct thread *td = curthread;
760 struct proc *p = td->td_proc;
761 struct filedesc *fdp;
4336d5df
JS
762
763 KKASSERT(p);
764 fdp = p->p_fd;
765
5b287bba
MD
766 if (fd < 0)
767 return (EINVAL);
5e8cfac8 768
259b8ea0
MD
769 /*
770 * NOTE: This function will skip unassociated descriptors and
771 * reserved descriptors that have not yet been assigned.
772 * fd_lastfile can change as a side effect of kern_close().
773 */
5b287bba 774 spin_lock_wr(&fdp->fd_spin);
259b8ea0
MD
775 while (fd <= fdp->fd_lastfile) {
776 if (fdp->fd_files[fd].fp != NULL) {
5b287bba
MD
777 spin_unlock_wr(&fdp->fd_spin);
778 /* ok if this races another close */
259b8ea0
MD
779 if (kern_close(fd) == EINTR)
780 return (EINTR);
5b287bba 781 spin_lock_wr(&fdp->fd_spin);
259b8ea0
MD
782 }
783 ++fd;
784 }
5b287bba 785 spin_unlock_wr(&fdp->fd_spin);
4336d5df
JS
786 return (0);
787}
788
984263bc
MD
789/*
790 * Close a file descriptor.
5b287bba
MD
791 *
792 * MPSAFE
984263bc 793 */
984263bc 794int
753fd850 795sys_close(struct close_args *uap)
12693083
MD
796{
797 return(kern_close(uap->fd));
798}
799
5b287bba
MD
800/*
801 * MPALMOSTSAFE - acquires mplock around knote_fdclose() calls
802 */
12693083
MD
803int
804kern_close(int fd)
984263bc 805{
dadab5e9
MD
806 struct thread *td = curthread;
807 struct proc *p = td->td_proc;
808 struct filedesc *fdp;
41c20dac 809 struct file *fp;
984263bc
MD
810 int error;
811 int holdleaders;
812
dadab5e9
MD
813 KKASSERT(p);
814 fdp = p->p_fd;
815
5b287bba
MD
816 spin_lock_wr(&fdp->fd_spin);
817 if ((fp = funsetfd_locked(fdp, fd)) == NULL) {
818 spin_unlock_wr(&fdp->fd_spin);
984263bc 819 return (EBADF);
5b287bba 820 }
984263bc
MD
821 holdleaders = 0;
822 if (p->p_fdtol != NULL) {
823 /*
824 * Ask fdfree() to sleep to ensure that all relevant
825 * process leaders can be traversed in closef().
826 */
827 fdp->fd_holdleaderscount++;
828 holdleaders = 1;
829 }
830
831 /*
832 * we now hold the fp reference that used to be owned by the descriptor
833 * array.
834 */
5b287bba
MD
835 spin_unlock_wr(&fdp->fd_spin);
836 if (fd < fdp->fd_knlistsize) {
837 get_mplock();
7749886d
MD
838 if (fd < fdp->fd_knlistsize)
839 knote_fdclose(p, fd);
5b287bba
MD
840 rel_mplock();
841 }
b8477cda 842 error = closef(fp, p);
984263bc 843 if (holdleaders) {
5b287bba 844 spin_lock_wr(&fdp->fd_spin);
984263bc
MD
845 fdp->fd_holdleaderscount--;
846 if (fdp->fd_holdleaderscount == 0 &&
847 fdp->fd_holdleaderswakeup != 0) {
848 fdp->fd_holdleaderswakeup = 0;
5b287bba 849 spin_unlock_wr(&fdp->fd_spin);
984263bc 850 wakeup(&fdp->fd_holdleaderscount);
5b287bba
MD
851 } else {
852 spin_unlock_wr(&fdp->fd_spin);
984263bc
MD
853 }
854 }
855 return (error);
856}
857
004d2de5
MD
858/*
859 * shutdown_args(int fd, int how)
860 */
861int
862kern_shutdown(int fd, int how)
863{
864 struct thread *td = curthread;
865 struct proc *p = td->td_proc;
004d2de5
MD
866 struct file *fp;
867 int error;
868
869 KKASSERT(p);
870
5b287bba 871 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL)
004d2de5 872 return (EBADF);
87de5057 873 error = fo_shutdown(fp, how);
9f87144f 874 fdrop(fp);
004d2de5
MD
875
876 return (error);
877}
878
879int
753fd850 880sys_shutdown(struct shutdown_args *uap)
004d2de5
MD
881{
882 int error;
883
884 error = kern_shutdown(uap->s, uap->how);
885
886 return (error);
887}
888
984263bc 889int
8f6f8622 890kern_fstat(int fd, struct stat *ub)
984263bc 891{
dadab5e9
MD
892 struct thread *td = curthread;
893 struct proc *p = td->td_proc;
41c20dac 894 struct file *fp;
984263bc
MD
895 int error;
896
dadab5e9 897 KKASSERT(p);
8f6f8622 898
5b287bba 899 if ((fp = holdfp(p->p_fd, fd, -1)) == NULL)
984263bc 900 return (EBADF);
87de5057 901 error = fo_stat(fp, ub, p->p_ucred);
9f87144f 902 fdrop(fp);
8f6f8622 903
984263bc
MD
904 return (error);
905}
984263bc
MD
906
907/*
908 * Return status information about a file descriptor.
909 */
984263bc 910int
753fd850 911sys_fstat(struct fstat_args *uap)
984263bc 912{
8f6f8622 913 struct stat st;
984263bc
MD
914 int error;
915
8f6f8622
DRJ
916 error = kern_fstat(uap->fd, &st);
917
984263bc 918 if (error == 0)
8f6f8622 919 error = copyout(&st, uap->sb, sizeof(st));
984263bc
MD
920 return (error);
921}
922
984263bc
MD
923/*
924 * Return pathconf information about a file descriptor.
925 */
984263bc
MD
926/* ARGSUSED */
927int
753fd850 928sys_fpathconf(struct fpathconf_args *uap)
984263bc 929{
dadab5e9
MD
930 struct thread *td = curthread;
931 struct proc *p = td->td_proc;
984263bc
MD
932 struct file *fp;
933 struct vnode *vp;
934 int error = 0;
935
dadab5e9 936 KKASSERT(p);
984263bc 937
5b287bba
MD
938 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL)
939 return (EBADF);
984263bc
MD
940
941 switch (fp->f_type) {
942 case DTYPE_PIPE:
943 case DTYPE_SOCKET:
944 if (uap->name != _PC_PIPE_BUF) {
945 error = EINVAL;
946 } else {
c7114eea 947 uap->sysmsg_result = PIPE_BUF;
984263bc
MD
948 error = 0;
949 }
950 break;
951 case DTYPE_FIFO:
952 case DTYPE_VNODE:
953 vp = (struct vnode *)fp->f_data;
c7114eea 954 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
984263bc
MD
955 break;
956 default:
957 error = EOPNOTSUPP;
958 break;
959 }
9f87144f 960 fdrop(fp);
984263bc
MD
961 return(error);
962}
963
984263bc
MD
964static int fdexpand;
965SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
966
5b287bba
MD
967/*
968 * Grow the file table so it can hold through descriptor (want).
969 *
970 * The fdp's spinlock must be held exclusively on entry and may be held
971 * exclusively on return. The spinlock may be cycled by the routine.
972 *
973 * MPSAFE
974 */
69908319 975static void
5b287bba 976fdgrow_locked(struct filedesc *fdp, int want)
69908319 977{
0679adc4
MD
978 struct fdnode *newfiles;
979 struct fdnode *oldfiles;
69908319
JH
980 int nf, extra;
981
982 nf = fdp->fd_nfiles;
983 do {
984 /* nf has to be of the form 2^n - 1 */
985 nf = 2 * nf + 1;
986 } while (nf <= want);
987
5b287bba 988 spin_unlock_wr(&fdp->fd_spin);
efda3bd0 989 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK);
5b287bba 990 spin_lock_wr(&fdp->fd_spin);
69908319
JH
991
992 /*
5b287bba
MD
993 * We could have raced another extend while we were not holding
994 * the spinlock.
69908319
JH
995 */
996 if (fdp->fd_nfiles >= nf) {
5b287bba 997 spin_unlock_wr(&fdp->fd_spin);
efda3bd0 998 kfree(newfiles, M_FILEDESC);
5b287bba 999 spin_lock_wr(&fdp->fd_spin);
69908319
JH
1000 return;
1001 }
69908319
JH
1002 /*
1003 * Copy the existing ofile and ofileflags arrays
1004 * and zero the new portion of each array.
1005 */
1006 extra = nf - fdp->fd_nfiles;
0679adc4
MD
1007 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode));
1008 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode));
1009
1010 oldfiles = fdp->fd_files;
1011 fdp->fd_files = newfiles;
69908319 1012 fdp->fd_nfiles = nf;
0679adc4 1013
5b287bba
MD
1014 if (oldfiles != fdp->fd_builtin_files) {
1015 spin_unlock_wr(&fdp->fd_spin);
efda3bd0 1016 kfree(oldfiles, M_FILEDESC);
5b287bba
MD
1017 spin_lock_wr(&fdp->fd_spin);
1018 }
69908319
JH
1019 fdexpand++;
1020}
1021
1022/*
1023 * Number of nodes in right subtree, including the root.
1024 */
1025static __inline int
1026right_subtree_size(int n)
1027{
1028 return (n ^ (n | (n + 1)));
1029}
1030
1031/*
1032 * Bigger ancestor.
1033 */
1034static __inline int
1035right_ancestor(int n)
1036{
1037 return (n | (n + 1));
1038}
1039
1040/*
1041 * Smaller ancestor.
1042 */
1043static __inline int
1044left_ancestor(int n)
1045{
1046 return ((n & (n + 1)) - 1);
1047}
1048
5b287bba
MD
1049/*
1050 * Traverse the in-place binary tree buttom-up adjusting the allocation
1051 * count so scans can determine where free descriptors are located.
1052 *
1053 * MPSAFE - caller must be holding an exclusive spinlock on fdp
1054 */
fa541be6 1055static
69908319 1056void
5b287bba 1057fdreserve_locked(struct filedesc *fdp, int fd, int incr)
69908319
JH
1058{
1059 while (fd >= 0) {
0679adc4
MD
1060 fdp->fd_files[fd].allocated += incr;
1061 KKASSERT(fdp->fd_files[fd].allocated >= 0);
69908319
JH
1062 fd = left_ancestor(fd);
1063 }
1064}
1065
1066/*
259b8ea0
MD
1067 * Reserve a file descriptor for the process. If no error occurs, the
1068 * caller MUST at some point call fsetfd() or assign a file pointer
1069 * or dispose of the reservation.
5b287bba
MD
1070 *
1071 * MPSAFE
69908319 1072 */
984263bc 1073int
dda4b42b 1074fdalloc(struct proc *p, int want, int *result)
984263bc 1075{
41c20dac 1076 struct filedesc *fdp = p->p_fd;
69908319
JH
1077 int fd, rsize, rsum, node, lim;
1078
5b287bba 1079 spin_lock_rd(&p->p_limit->p_spin);
69908319 1080 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
5b287bba 1081 spin_unlock_rd(&p->p_limit->p_spin);
69908319
JH
1082 if (want >= lim)
1083 return (EMFILE);
5b287bba 1084 spin_lock_wr(&fdp->fd_spin);
69908319 1085 if (want >= fdp->fd_nfiles)
5b287bba 1086 fdgrow_locked(fdp, want);
984263bc
MD
1087
1088 /*
1089 * Search for a free descriptor starting at the higher
1090 * of want or fd_freefile. If that fails, consider
1091 * expanding the ofile array.
259b8ea0
MD
1092 *
1093 * NOTE! the 'allocated' field is a cumulative recursive allocation
1094 * count. If we happen to see a value of 0 then we can shortcut
1095 * our search. Otherwise we run through through the tree going
1096 * down branches we know have free descriptor(s) until we hit a
1097 * leaf node. The leaf node will be free but will not necessarily
1098 * have an allocated field of 0.
984263bc 1099 */
69908319
JH
1100retry:
1101 /* move up the tree looking for a subtree with a free node */
1102 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim);
1103 fd = right_ancestor(fd)) {
0679adc4 1104 if (fdp->fd_files[fd].allocated == 0)
69908319 1105 goto found;
984263bc 1106
69908319 1107 rsize = right_subtree_size(fd);
0679adc4 1108 if (fdp->fd_files[fd].allocated == rsize)
69908319 1109 continue; /* right subtree full */
984263bc
MD
1110
1111 /*
69908319
JH
1112 * Free fd is in the right subtree of the tree rooted at fd.
1113 * Call that subtree R. Look for the smallest (leftmost)
1114 * subtree of R with an unallocated fd: continue moving
1115 * down the left branch until encountering a full left
1116 * subtree, then move to the right.
984263bc 1117 */
69908319
JH
1118 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) {
1119 node = fd + rsize;
0679adc4
MD
1120 rsum += fdp->fd_files[node].allocated;
1121 if (fdp->fd_files[fd].allocated == rsum + rsize) {
69908319 1122 fd = node; /* move to the right */
0679adc4 1123 if (fdp->fd_files[node].allocated == 0)
69908319
JH
1124 goto found;
1125 rsum = 0;
1126 }
984263bc 1127 }
69908319 1128 goto found;
984263bc 1129 }
69908319
JH
1130
1131 /*
1132 * No space in current array. Expand?
1133 */
5b287bba
MD
1134 if (fdp->fd_nfiles >= lim) {
1135 spin_unlock_wr(&fdp->fd_spin);
69908319 1136 return (EMFILE);
5b287bba
MD
1137 }
1138 fdgrow_locked(fdp, want);
69908319
JH
1139 goto retry;
1140
1141found:
1142 KKASSERT(fd < fdp->fd_nfiles);
69908319
JH
1143 if (fd > fdp->fd_lastfile)
1144 fdp->fd_lastfile = fd;
1145 if (want <= fdp->fd_freefile)
1146 fdp->fd_freefile = fd;
1147 *result = fd;
0679adc4 1148 KKASSERT(fdp->fd_files[fd].fp == NULL);
259b8ea0
MD
1149 KKASSERT(fdp->fd_files[fd].reserved == 0);
1150 fdp->fd_files[fd].fileflags = 0;
1151 fdp->fd_files[fd].reserved = 1;
5b287bba
MD
1152 fdreserve_locked(fdp, fd, 1);
1153 spin_unlock_wr(&fdp->fd_spin);
984263bc
MD
1154 return (0);
1155}
1156
1157/*
1158 * Check to see whether n user file descriptors
1159 * are available to the process p.
5b287bba
MD
1160 *
1161 * MPSAFE
984263bc
MD
1162 */
1163int
7bf8660a 1164fdavail(struct proc *p, int n)
984263bc 1165{
41c20dac 1166 struct filedesc *fdp = p->p_fd;
0679adc4 1167 struct fdnode *fdnode;
41c20dac 1168 int i, lim, last;
984263bc 1169
5b287bba 1170 spin_lock_rd(&p->p_limit->p_spin);
984263bc 1171 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
5b287bba 1172 spin_unlock_rd(&p->p_limit->p_spin);
984263bc 1173
5b287bba
MD
1174 spin_lock_rd(&fdp->fd_spin);
1175 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) {
1176 spin_unlock_rd(&fdp->fd_spin);
1177 return (1);
1178 }
984263bc 1179 last = min(fdp->fd_nfiles, lim);
0679adc4
MD
1180 fdnode = &fdp->fd_files[fdp->fd_freefile];
1181 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) {
5b287bba
MD
1182 if (fdnode->fp == NULL && --n <= 0) {
1183 spin_unlock_rd(&fdp->fd_spin);
984263bc 1184 return (1);
5b287bba 1185 }
984263bc 1186 }
5b287bba 1187 spin_unlock_rd(&fdp->fd_spin);
984263bc
MD
1188 return (0);
1189}
1190
b8477cda
MD
1191/*
1192 * Revoke open descriptors referencing (f_data, f_type)
1193 *
1194 * Any revoke executed within a prison is only able to
1195 * revoke descriptors for processes within that prison.
1196 *
1197 * Returns 0 on success or an error code.
1198 */
1199struct fdrevoke_info {
1200 void *data;
1201 short type;
1202 short unused;
1203 int count;
ea8f324c 1204 int intransit;
b8477cda
MD
1205 struct ucred *cred;
1206 struct file *nfp;
1207};
1208
ea8f324c
MD
1209static int fdrevoke_check_callback(struct file *fp, void *vinfo);
1210static int fdrevoke_proc_callback(struct proc *p, void *vinfo);
b8477cda
MD
1211
1212int
1213fdrevoke(void *f_data, short f_type, struct ucred *cred)
1214{
1215 struct fdrevoke_info info;
1216 int error;
1217
1218 bzero(&info, sizeof(info));
1219 info.data = f_data;
1220 info.type = f_type;
1221 info.cred = cred;
1222 error = falloc(NULL, &info.nfp, NULL);
1223 if (error)
1224 return (error);
ea8f324c
MD
1225
1226 /*
1227 * Scan the file pointer table once. dups do not dup file pointers,
1228 * only descriptors, so there is no leak. Set FREVOKED on the fps
1229 * being revoked.
1230 */
1231 allfiles_scan_exclusive(fdrevoke_check_callback, &info);
1232
1233 /*
1234 * If any fps were marked track down the related descriptors
1235 * and close them. Any dup()s at this point will notice
1236 * the FREVOKED already set in the fp and do the right thing.
1237 *
1238 * Any fps with non-zero msgcounts (aka sent over a unix-domain
1239 * socket) bumped the intransit counter and will require a
1240 * scan. Races against fps leaving the socket are closed by
1241 * the socket code checking for FREVOKED.
1242 */
1243 if (info.count)
1244 allproc_scan(fdrevoke_proc_callback, &info);
1245 if (info.intransit)
1246 unp_revoke_gc(info.nfp);
b8477cda 1247 fdrop(info.nfp);
ea8f324c 1248 return(0);
b8477cda
MD
1249}
1250
ea8f324c
MD
1251/*
1252 * Locate matching file pointers directly.
1253 */
b8477cda 1254static int
ea8f324c
MD
1255fdrevoke_check_callback(struct file *fp, void *vinfo)
1256{
1257 struct fdrevoke_info *info = vinfo;
1258
1259 /*
1260 * File pointers already flagged for revokation are skipped.
1261 */
1262 if (fp->f_flag & FREVOKED)
1263 return(0);
1264
1265 /*
1266 * If revoking from a prison file pointers created outside of
1267 * that prison, or file pointers without creds, cannot be revoked.
1268 */
1269 if (info->cred->cr_prison &&
1270 (fp->f_cred == NULL ||
1271 info->cred->cr_prison != fp->f_cred->cr_prison)) {
1272 return(0);
1273 }
1274
1275 /*
1276 * If the file pointer matches then mark it for revocation. The
1277 * flag is currently only used by unp_revoke_gc().
1278 *
1279 * info->count is a heuristic and can race in a SMP environment.
1280 */
1281 if (info->data == fp->f_data && info->type == fp->f_type) {
1282 atomic_set_int(&fp->f_flag, FREVOKED);
1283 info->count += fp->f_count;
1284 if (fp->f_msgcount)
1285 ++info->intransit;
1286 }
1287 return(0);
1288}
1289
1290/*
1291 * Locate matching file pointers via process descriptor tables.
1292 */
1293static int
1294fdrevoke_proc_callback(struct proc *p, void *vinfo)
b8477cda
MD
1295{
1296 struct fdrevoke_info *info = vinfo;
1297 struct filedesc *fdp;
1298 struct file *fp;
1299 int n;
1300
1301 if (p->p_stat == SIDL || p->p_stat == SZOMB)
1302 return(0);
1303 if (info->cred->cr_prison &&
1304 info->cred->cr_prison != p->p_ucred->cr_prison) {
1305 return(0);
1306 }
1307
1308 /*
1309 * If the controlling terminal of the process matches the
1310 * vnode being revoked we clear the controlling terminal.
1311 *
1312 * The normal spec_close() may not catch this because it
1313 * uses curproc instead of p.
1314 */
1315 if (p->p_session && info->type == DTYPE_VNODE &&
1316 info->data == p->p_session->s_ttyvp) {
1317 p->p_session->s_ttyvp = NULL;
1318 vrele(info->data);
1319 }
1320
1321 /*
0a4a9c77 1322 * Softref the fdp to prevent it from being destroyed
b8477cda 1323 */
0a4a9c77
MD
1324 spin_lock_wr(&p->p_spin);
1325 if ((fdp = p->p_fd) == NULL) {
1326 spin_unlock_wr(&p->p_spin);
b8477cda 1327 return(0);
0a4a9c77
MD
1328 }
1329 atomic_add_int(&fdp->fd_softrefs, 1);
1330 spin_unlock_wr(&p->p_spin);
1331
1332 /*
1333 * Locate and close any matching file descriptors.
1334 */
b8477cda
MD
1335 spin_lock_wr(&fdp->fd_spin);
1336 for (n = 0; n < fdp->fd_nfiles; ++n) {
1337 if ((fp = fdp->fd_files[n].fp) == NULL)
1338 continue;
ea8f324c 1339 if (fp->f_flag & FREVOKED) {
b8477cda
MD
1340 fhold(info->nfp);
1341 fdp->fd_files[n].fp = info->nfp;
1342 spin_unlock_wr(&fdp->fd_spin);
1343 closef(fp, p);
1344 spin_lock_wr(&fdp->fd_spin);
ea8f324c 1345 --info->count;
b8477cda
MD
1346 }
1347 }
1348 spin_unlock_wr(&fdp->fd_spin);
0a4a9c77 1349 atomic_subtract_int(&fdp->fd_softrefs, 1);
b8477cda
MD
1350 return(0);
1351}
1352
984263bc 1353/*
39f91578 1354 * falloc:
259b8ea0
MD
1355 * Create a new open file structure and reserve a file decriptor
1356 * for the process that refers to it.
1357 *
1358 * Root creds are checked using p, or assumed if p is NULL. If
1359 * resultfd is non-NULL then p must also be non-NULL. No file
1360 * descriptor is reserved if resultfd is NULL.
fad57d0e 1361 *
259b8ea0
MD
1362 * A file pointer with a refcount of 1 is returned. Note that the
1363 * file pointer is NOT associated with the descriptor. If falloc
1364 * returns success, fsetfd() MUST be called to either associate the
1365 * file pointer or clear the reservation.
5b287bba 1366 *
2dd63755 1367 * MPSAFE
984263bc
MD
1368 */
1369int
39f91578 1370falloc(struct proc *p, struct file **resultfp, int *resultfd)
984263bc 1371{
c4cb6d8b
HP
1372 static struct timeval lastfail;
1373 static int curfail;
fad57d0e
MD
1374 struct file *fp;
1375 int error;
c4cb6d8b 1376
fad57d0e
MD
1377 fp = NULL;
1378
1379 /*
1380 * Handle filetable full issues and root overfill.
1381 */
60ee93b9 1382 if (nfiles >= maxfiles - maxfilesrootres &&
9b3f1fd5 1383 ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) {
c4cb6d8b 1384 if (ppsratecheck(&lastfail, &curfail, 1)) {
6ea70f76 1385 kprintf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n",
9b3f1fd5 1386 (p ? p->p_ucred->cr_ruid : -1));
c4cb6d8b 1387 }
fad57d0e
MD
1388 error = ENFILE;
1389 goto done;
984263bc 1390 }
fad57d0e 1391
984263bc
MD
1392 /*
1393 * Allocate a new file descriptor.
984263bc 1394 */
efda3bd0 1395 fp = kmalloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO);
85fceac1 1396 spin_init(&fp->f_spin);
984263bc 1397 fp->f_count = 1;
984263bc
MD
1398 fp->f_ops = &badfileops;
1399 fp->f_seqcount = 1;
fad57d0e 1400 if (p)
a235f7bb 1401 fp->f_cred = crhold(p->p_ucred);
fad57d0e
MD
1402 else
1403 fp->f_cred = crhold(proc0.p_ucred);
2dd63755
MD
1404 spin_lock_wr(&filehead_spin);
1405 nfiles++;
fad57d0e 1406 LIST_INSERT_HEAD(&filehead, fp, f_list);
2dd63755 1407 spin_unlock_wr(&filehead_spin);
fad57d0e 1408 if (resultfd) {
259b8ea0 1409 if ((error = fdalloc(p, 0, resultfd)) != 0) {
9f87144f 1410 fdrop(fp);
fad57d0e 1411 fp = NULL;
39f91578 1412 }
a235f7bb 1413 } else {
fad57d0e 1414 error = 0;
984263bc 1415 }
fad57d0e
MD
1416done:
1417 *resultfp = fp;
64f33bc8 1418 return (error);
fad57d0e
MD
1419}
1420
85fceac1
MD
1421/*
1422 * MPSAFE
1423 */
1424static
1425int
1426checkfpclosed(struct filedesc *fdp, int fd, struct file *fp)
1427{
1428 int error;
1429
1430 spin_lock_rd(&fdp->fd_spin);
1431 if ((unsigned) fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp)
1432 error = EBADF;
1433 else
1434 error = 0;
1435 spin_unlock_rd(&fdp->fd_spin);
1436 return (error);
1437}
1438
fad57d0e 1439/*
259b8ea0
MD
1440 * Associate a file pointer with a previously reserved file descriptor.
1441 * This function always succeeds.
1442 *
1443 * If fp is NULL, the file descriptor is returned to the pool.
fad57d0e 1444 */
fad57d0e 1445
5b287bba
MD
1446/*
1447 * MPSAFE (exclusive spinlock must be held on call)
1448 */
1449static void
1450fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd)
1451{
259b8ea0
MD
1452 KKASSERT((unsigned)fd < fdp->fd_nfiles);
1453 KKASSERT(fdp->fd_files[fd].reserved != 0);
1454 if (fp) {
fad57d0e 1455 fhold(fp);
259b8ea0
MD
1456 fdp->fd_files[fd].fp = fp;
1457 fdp->fd_files[fd].reserved = 0;
d9b2033e
MD
1458 if (fp->f_type == DTYPE_KQUEUE) {
1459 if (fdp->fd_knlistsize < 0)
1460 fdp->fd_knlistsize = 0;
1461 }
259b8ea0
MD
1462 } else {
1463 fdp->fd_files[fd].reserved = 0;
5b287bba
MD
1464 fdreserve_locked(fdp, fd, -1);
1465 fdfixup_locked(fdp, fd);
fad57d0e 1466 }
984263bc
MD
1467}
1468
5b287bba
MD
1469/*
1470 * MPSAFE
1471 */
1472void
1473fsetfd(struct proc *p, struct file *fp, int fd)
1474{
1475 struct filedesc *fdp = p->p_fd;
1476
1477 spin_lock_wr(&fdp->fd_spin);
1478 fsetfd_locked(fdp, fp, fd);
1479 spin_unlock_wr(&fdp->fd_spin);
1480}
1481
1482/*
1483 * MPSAFE (exclusive spinlock must be held on call)
1484 */
fa541be6 1485static
259b8ea0 1486struct file *
5b287bba 1487funsetfd_locked(struct filedesc *fdp, int fd)
69908319 1488{
259b8ea0
MD
1489 struct file *fp;
1490
1491 if ((unsigned)fd >= fdp->fd_nfiles)
1492 return (NULL);
1493 if ((fp = fdp->fd_files[fd].fp) == NULL)
1494 return (NULL);
0679adc4
MD
1495 fdp->fd_files[fd].fp = NULL;
1496 fdp->fd_files[fd].fileflags = 0;
259b8ea0 1497
5b287bba
MD
1498 fdreserve_locked(fdp, fd, -1);
1499 fdfixup_locked(fdp, fd);
259b8ea0 1500 return(fp);
69908319
JH
1501}
1502
85fceac1
MD
1503/*
1504 * MPSAFE
1505 */
1506int
1507fgetfdflags(struct filedesc *fdp, int fd, int *flagsp)
1508{
1509 int error;
1510
1511 spin_lock_rd(&fdp->fd_spin);
1512 if (((u_int)fd) >= fdp->fd_nfiles) {
1513 error = EBADF;
1514 } else if (fdp->fd_files[fd].fp == NULL) {
1515 error = EBADF;
1516 } else {
1517 *flagsp = fdp->fd_files[fd].fileflags;
1518 error = 0;
1519 }
1520 spin_unlock_rd(&fdp->fd_spin);
1521 return (error);
1522}
1523
1524/*
1525 * MPSAFE
1526 */
228b401d
MD
1527int
1528fsetfdflags(struct filedesc *fdp, int fd, int add_flags)
1529{
85fceac1
MD
1530 int error;
1531
1532 spin_lock_wr(&fdp->fd_spin);
1533 if (((u_int)fd) >= fdp->fd_nfiles) {
1534 error = EBADF;
1535 } else if (fdp->fd_files[fd].fp == NULL) {
1536 error = EBADF;
1537 } else {
1538 fdp->fd_files[fd].fileflags |= add_flags;
1539 error = 0;
1540 }
1541 spin_unlock_wr(&fdp->fd_spin);
1542 return (error);
228b401d
MD
1543}
1544
85fceac1
MD
1545/*
1546 * MPSAFE
1547 */
228b401d
MD
1548int
1549fclrfdflags(struct filedesc *fdp, int fd, int rem_flags)
1550{
85fceac1
MD
1551 int error;
1552
1553 spin_lock_wr(&fdp->fd_spin);
1554 if (((u_int)fd) >= fdp->fd_nfiles) {
1555 error = EBADF;
1556 } else if (fdp->fd_files[fd].fp == NULL) {
1557 error = EBADF;
1558 } else {
1559 fdp->fd_files[fd].fileflags &= ~rem_flags;
1560 error = 0;
1561 }
1562 spin_unlock_wr(&fdp->fd_spin);
1563 return (error);
228b401d
MD
1564}
1565
a235f7bb
MD
1566void
1567fsetcred(struct file *fp, struct ucred *cr)
1568{
1569 crhold(cr);
1570 crfree(fp->f_cred);
1571 fp->f_cred = cr;
1572}
1573
984263bc
MD
1574/*
1575 * Free a file descriptor.
1576 */
5b287bba 1577static
984263bc 1578void
7bf8660a 1579ffree(struct file *fp)
984263bc
MD
1580{
1581 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!"));
2dd63755 1582 spin_lock_wr(&filehead_spin);
984263bc 1583 LIST_REMOVE(fp, f_list);
2dd63755
MD
1584 nfiles--;
1585 spin_unlock_wr(&filehead_spin);
984263bc 1586 crfree(fp->f_cred);
28623bf9
MD
1587 if (fp->f_nchandle.ncp)
1588 cache_drop(&fp->f_nchandle);
efda3bd0 1589 kfree(fp, M_FILE);
984263bc
MD
1590}
1591
228b401d
MD
1592/*
1593 * called from init_main, initialize filedesc0 for proc0.
1594 */
1595void
1596fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask)
1597{
1598 p0->p_fd = fdp0;
1599 p0->p_fdtol = NULL;
1600 fdp0->fd_refcnt = 1;
1601 fdp0->fd_cmask = cmask;
1602 fdp0->fd_files = fdp0->fd_builtin_files;
1603 fdp0->fd_nfiles = NDFILE;
259b8ea0 1604 fdp0->fd_lastfile = -1;
85fceac1 1605 spin_init(&fdp0->fd_spin);
228b401d
MD
1606}
1607
984263bc
MD
1608/*
1609 * Build a new filedesc structure.
5b287bba
MD
1610 *
1611 * NOT MPSAFE (vref)
984263bc
MD
1612 */
1613struct filedesc *
7bf8660a 1614fdinit(struct proc *p)
984263bc 1615{
0679adc4 1616 struct filedesc *newfdp;
41c20dac 1617 struct filedesc *fdp = p->p_fd;
984263bc 1618
efda3bd0 1619 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO);
5b287bba 1620 spin_lock_rd(&fdp->fd_spin);
bccde7a3 1621 if (fdp->fd_cdir) {
0679adc4
MD
1622 newfdp->fd_cdir = fdp->fd_cdir;
1623 vref(newfdp->fd_cdir);
28623bf9 1624 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir);
690a3127 1625 }
bccde7a3
MD
1626
1627 /*
1628 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of
1629 * proc0, but should unconditionally exist in other processes.
1630 */
1631 if (fdp->fd_rdir) {
0679adc4
MD
1632 newfdp->fd_rdir = fdp->fd_rdir;
1633 vref(newfdp->fd_rdir);
28623bf9 1634 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir);
bccde7a3
MD
1635 }
1636 if (fdp->fd_jdir) {
0679adc4
MD
1637 newfdp->fd_jdir = fdp->fd_jdir;
1638 vref(newfdp->fd_jdir);
28623bf9 1639 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir);
690a3127 1640 }
5b287bba 1641 spin_unlock_rd(&fdp->fd_spin);
690a3127 1642
984263bc 1643 /* Create the file descriptor table. */
0679adc4
MD
1644 newfdp->fd_refcnt = 1;
1645 newfdp->fd_cmask = cmask;
1646 newfdp->fd_files = newfdp->fd_builtin_files;
1647 newfdp->fd_nfiles = NDFILE;
1648 newfdp->fd_knlistsize = -1;
259b8ea0 1649 newfdp->fd_lastfile = -1;
85fceac1 1650 spin_init(&newfdp->fd_spin);
0679adc4
MD
1651
1652 return (newfdp);
984263bc
MD
1653}
1654
1655/*
1656 * Share a filedesc structure.
5b287bba
MD
1657 *
1658 * MPSAFE
984263bc
MD
1659 */
1660struct filedesc *
7bf8660a 1661fdshare(struct proc *p)
984263bc 1662{
5b287bba
MD
1663 struct filedesc *fdp;
1664
1665 fdp = p->p_fd;
1666 spin_lock_wr(&fdp->fd_spin);
1667 fdp->fd_refcnt++;
1668 spin_unlock_wr(&fdp->fd_spin);
1669 return (fdp);
984263bc
MD
1670}
1671
1672/*
1673 * Copy a filedesc structure.
5b287bba
MD
1674 *
1675 * MPSAFE
984263bc
MD
1676 */
1677struct filedesc *
7bf8660a 1678fdcopy(struct proc *p)
984263bc 1679{
5b287bba
MD
1680 struct filedesc *fdp = p->p_fd;
1681 struct filedesc *newfdp;
0679adc4 1682 struct fdnode *fdnode;
41c20dac 1683 int i;
5b287bba 1684 int ni;
984263bc 1685
5b287bba
MD
1686 /*
1687 * Certain daemons might not have file descriptors.
1688 */
984263bc
MD
1689 if (fdp == NULL)
1690 return (NULL);
1691
5b287bba
MD
1692 /*
1693 * Allocate the new filedesc and fd_files[] array. This can race
1694 * with operations by other threads on the fdp so we have to be
1695 * careful.
1696 */
efda3bd0 1697 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK | M_ZERO);
5b287bba
MD
1698again:
1699 spin_lock_rd(&fdp->fd_spin);
1700 if (fdp->fd_lastfile < NDFILE) {
1701 newfdp->fd_files = newfdp->fd_builtin_files;
1702 i = NDFILE;
1703 } else {
1704 /*
1705 * We have to allocate (N^2-1) entries for our in-place
1706 * binary tree. Allow the table to shrink.
1707 */
1708 i = fdp->fd_nfiles;
1709 ni = (i - 1) / 2;
1710 while (ni > fdp->fd_lastfile && ni > NDFILE) {
1711 i = ni;
1712 ni = (i - 1) / 2;
1713 }
1714 spin_unlock_rd(&fdp->fd_spin);
77652cad 1715 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode),
5b287bba
MD
1716 M_FILEDESC, M_WAITOK | M_ZERO);
1717
1718 /*
1719 * Check for race, retry
1720 */
1721 spin_lock_rd(&fdp->fd_spin);
1722 if (i <= fdp->fd_lastfile) {
1723 spin_unlock_rd(&fdp->fd_spin);
efda3bd0 1724 kfree(newfdp->fd_files, M_FILEDESC);
5b287bba
MD
1725 goto again;
1726 }
1727 }
1728
1729 /*
1730 * Dup the remaining fields. vref() and cache_hold() can be
1731 * safely called while holding the read spinlock on fdp.
1732 *
1733 * The read spinlock on fdp is still being held.
1734 *
1735 * NOTE: vref and cache_hold calls for the case where the vnode
1736 * or cache entry already has at least one ref may be called
1737 * while holding spin locks.
1738 */
1739 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) {
597aea93 1740 vref(newfdp->fd_cdir);
28623bf9 1741 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir);
690a3127 1742 }
6bdbb368
DR
1743 /*
1744 * We must check for fd_rdir here, at least for now because
1745 * the init process is created before we have access to the
1746 * rootvode to take a reference to it.
1747 */
5b287bba 1748 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) {
597aea93 1749 vref(newfdp->fd_rdir);
28623bf9 1750 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir);
690a3127 1751 }
5b287bba 1752 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) {
597aea93 1753 vref(newfdp->fd_jdir);
28623bf9 1754 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir);
690a3127 1755 }
984263bc 1756 newfdp->fd_refcnt = 1;
984263bc 1757 newfdp->fd_nfiles = i;
5b287bba
MD
1758 newfdp->fd_lastfile = fdp->fd_lastfile;
1759 newfdp->fd_freefile = fdp->fd_freefile;
1760 newfdp->fd_cmask = fdp->fd_cmask;
1761 newfdp->fd_knlist = NULL;
1762 newfdp->fd_knlistsize = -1;
1763 newfdp->fd_knhash = NULL;
1764 newfdp->fd_knhashmask = 0;
1765 spin_init(&newfdp->fd_spin);
984263bc
MD
1766
1767 /*
5b287bba
MD
1768 * Copy the descriptor table through (i). This also copies the
1769 * allocation state. Then go through and ref the file pointers
1770 * and clean up any KQ descriptors.
1771 *
259b8ea0
MD
1772 * kq descriptors cannot be copied. Since we haven't ref'd the
1773 * copied files yet we can ignore the return value from funsetfd().
5b287bba
MD
1774 *
1775 * The read spinlock on fdp is still being held.
984263bc 1776 */
5b287bba
MD
1777 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode));
1778 for (i = 0 ; i < newfdp->fd_nfiles; ++i) {
259b8ea0
MD
1779 fdnode = &newfdp->fd_files[i];
1780 if (fdnode->reserved) {
5b287bba 1781 fdreserve_locked(newfdp, i, -1);
259b8ea0 1782 fdnode->reserved = 0;
5b287bba
MD
1783 fdfixup_locked(newfdp, i);
1784 } else if (fdnode->fp) {
1785 if (fdnode->fp->f_type == DTYPE_KQUEUE) {
1786 (void)funsetfd_locked(newfdp, i);
1787 } else {
1788 fhold(fdnode->fp);
1789 }
259b8ea0 1790 }
984263bc 1791 }
5b287bba 1792 spin_unlock_rd(&fdp->fd_spin);
984263bc
MD
1793 return (newfdp);
1794}
1795
1796/*
1797 * Release a filedesc structure.
5b287bba
MD
1798 *
1799 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE)
984263bc
MD
1800 */
1801void
0a4a9c77 1802fdfree(struct proc *p, struct filedesc *repl)
984263bc 1803{
0a4a9c77 1804 struct filedesc *fdp;
0679adc4 1805 struct fdnode *fdnode;
41c20dac 1806 int i;
984263bc
MD
1807 struct filedesc_to_leader *fdtol;
1808 struct file *fp;
1809 struct vnode *vp;
1810 struct flock lf;
1811
0a4a9c77
MD
1812 /*
1813 * Certain daemons might not have file descriptors.
1814 */
464e801e
MD
1815 fdp = p->p_fd;
1816 if (fdp == NULL) {
1817 p->p_fd = repl;
984263bc 1818 return;
464e801e 1819 }
984263bc 1820
5b287bba 1821 /*
0a4a9c77 1822 * Severe messing around to follow.
5b287bba
MD
1823 */
1824 spin_lock_wr(&fdp->fd_spin);
1825
984263bc
MD
1826 /* Check for special need to clear POSIX style locks */
1827 fdtol = p->p_fdtol;
1828 if (fdtol != NULL) {
1829 KASSERT(fdtol->fdl_refcount > 0,
1830 ("filedesc_to_refcount botch: fdl_refcount=%d",
1831 fdtol->fdl_refcount));
1832 if (fdtol->fdl_refcount == 1 &&
1833 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
259b8ea0
MD
1834 for (i = 0; i <= fdp->fd_lastfile; ++i) {
1835 fdnode = &fdp->fd_files[i];
0679adc4 1836 if (fdnode->fp == NULL ||
259b8ea0 1837 fdnode->fp->f_type != DTYPE_VNODE) {
984263bc 1838 continue;
259b8ea0 1839 }
0679adc4 1840 fp = fdnode->fp;
984263bc 1841 fhold(fp);
5b287bba
MD
1842 spin_unlock_wr(&fdp->fd_spin);
1843
984263bc
MD
1844 lf.l_whence = SEEK_SET;
1845 lf.l_start = 0;
1846 lf.l_len = 0;
1847 lf.l_type = F_UNLCK;
1848 vp = (struct vnode *)fp->f_data;
1849 (void) VOP_ADVLOCK(vp,
1850 (caddr_t)p->p_leader,
1851 F_UNLCK,
1852 &lf,
1853 F_POSIX);
9f87144f 1854 fdrop(fp);
5b287bba 1855 spin_lock_wr(&fdp->fd_spin);
984263bc
MD
1856 }
1857 }
1858 retry:
1859 if (fdtol->fdl_refcount == 1) {
1860 if (fdp->fd_holdleaderscount > 0 &&
1861 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1862 /*
1863 * close() or do_dup() has cleared a reference
1864 * in a shared file descriptor table.
1865 */
1866 fdp->fd_holdleaderswakeup = 1;
7749886d
MD
1867 msleep(&fdp->fd_holdleaderscount,
1868 &fdp->fd_spin, 0, "fdlhold", 0);
984263bc
MD
1869 goto retry;
1870 }
1871 if (fdtol->fdl_holdcount > 0) {
1872 /*
1873 * Ensure that fdtol->fdl_leader
1874 * remains valid in closef().
1875 */
1876 fdtol->fdl_wakeup = 1;
7749886d 1877 msleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0);
984263bc
MD
1878 goto retry;
1879 }
1880 }
1881 fdtol->fdl_refcount--;
1882 if (fdtol->fdl_refcount == 0 &&
1883 fdtol->fdl_holdcount == 0) {
1884 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1885 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
5b287bba 1886 } else {
984263bc 1887 fdtol = NULL;
5b287bba 1888 }
984263bc 1889 p->p_fdtol = NULL;
5b287bba
MD
1890 if (fdtol != NULL) {
1891 spin_unlock_wr(&fdp->fd_spin);
efda3bd0 1892 kfree(fdtol, M_FILEDESC_TO_LEADER);
5b287bba
MD
1893 spin_lock_wr(&fdp->fd_spin);
1894 }
984263bc 1895 }
5b287bba
MD
1896 if (--fdp->fd_refcnt > 0) {
1897 spin_unlock_wr(&fdp->fd_spin);
464e801e
MD
1898 spin_lock_wr(&p->p_spin);
1899 p->p_fd = repl;
1900 spin_unlock_wr(&p->p_spin);
984263bc 1901 return;
5b287bba 1902 }
464e801e
MD
1903
1904 /*
1905 * Even though we are the last reference to the structure allproc
1906 * scans may still reference the structure. Maintain proper
1907 * locks until we can replace p->p_fd.
1908 *
1909 * Also note that kqueue's closef still needs to reference the
1910 * fdp via p->p_fd, so we have to close the descriptors before
1911 * we replace p->p_fd.
1912 */
1913 for (i = 0; i <= fdp->fd_lastfile; ++i) {
1914 if (fdp->fd_files[i].fp) {
1915 fp = funsetfd_locked(fdp, i);
1916 if (fp) {
1917 spin_unlock_wr(&fdp->fd_spin);
1918 closef(fp, p);
1919 spin_lock_wr(&fdp->fd_spin);
1920 }
1921 }
1922 }
5b287bba
MD
1923 spin_unlock_wr(&fdp->fd_spin);
1924
464e801e
MD
1925 /*
1926 * Interlock against an allproc scan operations (typically frevoke).
1927 */
1928 spin_lock_wr(&p->p_spin);
1929 p->p_fd = repl;
1930 spin_unlock_wr(&p->p_spin);
1931
0a4a9c77
MD
1932 /*
1933 * Wait for any softrefs to go away. This race rarely occurs so
1934 * we can use a non-critical-path style poll/sleep loop. The
1935 * race only occurs against allproc scans.
1936 *
1937 * No new softrefs can occur with the fdp disconnected from the
1938 * process.
1939 */
1940 if (fdp->fd_softrefs) {
1941 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid);
1942 while (fdp->fd_softrefs)
1943 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1);
1944 }
1945
0679adc4 1946 if (fdp->fd_files != fdp->fd_builtin_files)
efda3bd0 1947 kfree(fdp->fd_files, M_FILEDESC);
690a3127 1948 if (fdp->fd_cdir) {
28623bf9 1949 cache_drop(&fdp->fd_ncdir);
984263bc 1950 vrele(fdp->fd_cdir);
690a3127 1951 }
bccde7a3 1952 if (fdp->fd_rdir) {
28623bf9 1953 cache_drop(&fdp->fd_nrdir);
bccde7a3
MD
1954 vrele(fdp->fd_rdir);
1955 }
690a3127 1956 if (fdp->fd_jdir) {
28623bf9 1957 cache_drop(&fdp->fd_njdir);
984263bc 1958 vrele(fdp->fd_jdir);
690a3127 1959 }
984263bc 1960 if (fdp->fd_knlist)
efda3bd0 1961 kfree(fdp->fd_knlist, M_KQUEUE);
984263bc 1962 if (fdp->fd_knhash)
efda3bd0
MD
1963 kfree(fdp->fd_knhash, M_KQUEUE);
1964 kfree(fdp, M_FILEDESC);
984263bc
MD
1965}
1966
fa541be6
MD
1967/*
1968 * Retrieve and reference the file pointer associated with a descriptor.
85fceac1
MD
1969 *
1970 * MPSAFE
fa541be6
MD
1971 */
1972struct file *
1973holdfp(struct filedesc *fdp, int fd, int flag)
1974{
1975 struct file* fp;
1976
85fceac1
MD
1977 spin_lock_rd(&fdp->fd_spin);
1978 if (((u_int)fd) >= fdp->fd_nfiles) {
1979 fp = NULL;
1980 goto done;
1981 }
fa541be6 1982 if ((fp = fdp->fd_files[fd].fp) == NULL)
85fceac1
MD
1983 goto done;
1984 if ((fp->f_flag & flag) == 0 && flag != -1) {
1985 fp = NULL;
1986 goto done;
1987 }
fa541be6 1988 fhold(fp);
85fceac1
MD
1989done:
1990 spin_unlock_rd(&fdp->fd_spin);
fa541be6
MD
1991 return (fp);
1992}
1993
1994/*
1995 * holdsock() - load the struct file pointer associated
1996 * with a socket into *fpp. If an error occurs, non-zero
1997 * will be returned and *fpp will be set to NULL.
5b287bba
MD
1998 *
1999 * MPSAFE
fa541be6
MD
2000 */
2001int
5b287bba 2002holdsock(struct filedesc *fdp, int fd, struct file **fpp)
fa541be6
MD
2003{
2004 struct file *fp;
5b287bba 2005 int error;
fa541be6 2006
5b287bba
MD
2007 spin_lock_rd(&fdp->fd_spin);
2008 if ((unsigned)fd >= fdp->fd_nfiles) {
2009 error = EBADF;
2010 fp = NULL;
2011 goto done;
2012 }
2013 if ((fp = fdp->fd_files[fd].fp) == NULL) {
2014 error = EBADF;
2015 goto done;
2016 }
2017 if (fp->f_type != DTYPE_SOCKET) {
2018 error = ENOTSOCK;
2019 goto done;
2020 }
fa541be6 2021 fhold(fp);
5b287bba
MD
2022 error = 0;
2023done:
2024 spin_unlock_rd(&fdp->fd_spin);
fa541be6
MD
2025 *fpp = fp;
2026 return (error);
2027}
2028
228b401d 2029/*
5b287bba
MD
2030 * Convert a user file descriptor to a held file pointer.
2031 *
2032 * MPSAFE
228b401d
MD
2033 */
2034int
5b287bba 2035holdvnode(struct filedesc *fdp, int fd, struct file **fpp)
228b401d
MD
2036{
2037 struct file *fp;
5b287bba
MD
2038 int error;
2039
2040 spin_lock_rd(&fdp->fd_spin);
2041 if ((unsigned)fd >= fdp->fd_nfiles) {
2042 error = EBADF;
2043 fp = NULL;
2044 goto done;
2045 }
2046 if ((fp = fdp->fd_files[fd].fp) == NULL) {
2047 error = EBADF;
2048 goto done;
2049 }
2050 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) {
8f9f2535 2051 fp = NULL;
5b287bba
MD
2052 error = EINVAL;
2053 goto done;
2054 }
2055 fhold(fp);
2056 error = 0;
2057done:
2058 spin_unlock_rd(&fdp->fd_spin);
228b401d 2059 *fpp = fp;
5b287bba 2060 return (error);
228b401d
MD
2061}
2062
984263bc
MD
2063/*
2064 * For setugid programs, we don't want to people to use that setugidness
2065 * to generate error messages which write to a file which otherwise would
2066 * otherwise be off-limits to the process.
2067 *
2068 * This is a gross hack to plug the hole. A better solution would involve
2069 * a special vop or other form of generalized access control mechanism. We
2070 * go ahead and just reject all procfs file systems accesses as dangerous.
2071 *
2072 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
2073 * sufficient. We also don't for check setugidness since we know we are.
2074 */
2075static int
2076is_unsafe(struct file *fp)
2077{
2078 if (fp->f_type == DTYPE_VNODE &&
2079 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
2080 return (1);
2081 return (0);
2082}
2083
2084/*
2085 * Make this setguid thing safe, if at all possible.
5b287bba
MD
2086 *
2087 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose()
984263bc
MD
2088 */
2089void
dadab5e9 2090setugidsafety(struct proc *p)
984263bc
MD
2091{
2092 struct filedesc *fdp = p->p_fd;
41c20dac 2093 int i;
984263bc
MD
2094
2095 /* Certain daemons might not have file descriptors. */
2096 if (fdp == NULL)
2097 return;
2098
2099 /*
0679adc4 2100 * note: fdp->fd_files may be reallocated out from under us while
984263bc
MD
2101 * we are blocked in a close. Be careful!
2102 */
2103 for (i = 0; i <= fdp->fd_lastfile; i++) {
2104 if (i > 2)
2105 break;
0679adc4 2106 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) {
984263bc
MD
2107 struct file *fp;
2108
984263bc
MD
2109 if (i < fdp->fd_knlistsize)
2110 knote_fdclose(p, i);
2111 /*
2112 * NULL-out descriptor prior to close to avoid
2113 * a race while close blocks.
2114 */
5b287bba 2115 if ((fp = funsetfd_locked(fdp, i)) != NULL)
b8477cda 2116 closef(fp, p);
984263bc
MD
2117 }
2118 }
984263bc
MD
2119}
2120
2121/*
2122 * Close any files on exec?
5b287bba
MD
2123 *
2124 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose()
984263bc
MD
2125 */
2126void
dadab5e9 2127fdcloseexec(struct proc *p)
984263bc
MD
2128{
2129 struct filedesc *fdp = p->p_fd;
41c20dac 2130 int i;
984263bc
MD
2131
2132 /* Certain daemons might not have file descriptors. */
2133 if (fdp == NULL)
2134 return;
2135
2136 /*
0679adc4
MD
2137 * We cannot cache fd_files since operations may block and rip
2138 * them out from under us.
984263bc
MD
2139 */
2140 for (i = 0; i <= fdp->fd_lastfile; i++) {
0679adc4
MD
2141 if (fdp->fd_files[i].fp != NULL &&
2142 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) {
984263bc
MD
2143 struct file *fp;
2144
984263bc
MD
2145 if (i < fdp->fd_knlistsize)
2146 knote_fdclose(p, i);
2147 /*
2148 * NULL-out descriptor prior to close to avoid
2149 * a race while close blocks.
2150 */
5b287bba 2151 if ((fp = funsetfd_locked(fdp, i)) != NULL)
b8477cda 2152 closef(fp, p);
984263bc
MD
2153 }
2154 }
984263bc
MD
2155}
2156
2157/*
2158 * It is unsafe for set[ug]id processes to be started with file
2159 * descriptors 0..2 closed, as these descriptors are given implicit
2160 * significance in the Standard C library. fdcheckstd() will create a
2161 * descriptor referencing /dev/null for each of stdin, stdout, and
2162 * stderr that is not already open.
5b287bba
MD
2163 *
2164 * NOT MPSAFE - calls falloc, vn_open, etc
984263bc
MD
2165 */
2166int
dadab5e9 2167fdcheckstd(struct proc *p)
984263bc 2168{
fad57d0e 2169 struct nlookupdata nd;
dadab5e9
MD
2170 struct filedesc *fdp;
2171 struct file *fp;
973c11b9 2172 int retval;
259b8ea0 2173 int i, error, flags, devnull;
984263bc 2174
ea8f324c
MD
2175 fdp = p->p_fd;
2176 if (fdp == NULL)
2177 return (0);
2178 devnull = -1;
2179 error = 0;
2180 for (i = 0; i < 3; i++) {
0679adc4 2181 if (fdp->fd_files[i].fp != NULL)
fad57d0e
MD
2182 continue;
2183 if (devnull < 0) {
259b8ea0 2184 if ((error = falloc(p, &fp, &devnull)) != 0)
fad57d0e
MD
2185 break;
2186
2187 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE,
2188 NLC_FOLLOW|NLC_LOCKVP);
2189 flags = FREAD | FWRITE;
2190 if (error == 0)
2191 error = vn_open(&nd, fp, flags, 0);
2192 if (error == 0)
259b8ea0
MD
2193 fsetfd(p, fp, devnull);
2194 else
2195 fsetfd(p, NULL, devnull);
9f87144f 2196 fdrop(fp);
fad57d0e
MD
2197 nlookup_done(&nd);
2198 if (error)
2199 break;
259b8ea0 2200 KKASSERT(i == devnull);
fad57d0e
MD
2201 } else {
2202 error = kern_dup(DUP_FIXED, devnull, i, &retval);
2203 if (error != 0)
2204 break;
2205 }
ea8f324c
MD
2206 }
2207 return (error);
984263bc
MD
2208}
2209
2210/*
2211 * Internal form of close.
2212 * Decrement reference count on file structure.
dadab5e9 2213 * Note: td and/or p may be NULL when closing a file
984263bc 2214 * that was being passed in a message.
5b287bba
MD
2215 *
2216 * MPALMOSTSAFE - acquires mplock for VOP operations
984263bc
MD
2217 */
2218int
b8477cda 2219closef(struct file *fp, struct proc *p)
984263bc
MD
2220{
2221 struct vnode *vp;
2222 struct flock lf;
2223 struct filedesc_to_leader *fdtol;
2224
2225 if (fp == NULL)
2226 return (0);
b8477cda 2227
984263bc
MD
2228 /*
2229 * POSIX record locking dictates that any close releases ALL
2230 * locks owned by this process. This is handled by setting
2231 * a flag in the unlock to free ONLY locks obeying POSIX
2232 * semantics, and not to free BSD-style file locks.
2233 * If the descriptor was in a message, POSIX-style locks
2234 * aren't passed with the descriptor.
2235 */
7749886d
MD
2236 if (p != NULL && fp->f_type == DTYPE_VNODE &&
2237 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS)
2238 ) {
2239 get_mplock();
984263bc
MD
2240 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) {
2241 lf.l_whence = SEEK_SET;
2242 lf.l_start = 0;
2243 lf.l_len = 0;
2244 lf.l_type = F_UNLCK;
2245 vp = (struct vnode *)fp->f_data;
2246 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
2247 &lf, F_POSIX);
2248 }
2249 fdtol = p->p_fdtol;
2250 if (fdtol != NULL) {
2251 /*
2252 * Handle special case where file descriptor table
2253 * is shared between multiple process leaders.
2254 */
2255 for (fdtol = fdtol->fdl_next;
2256 fdtol != p->p_fdtol;
2257 fdtol = fdtol->fdl_next) {
2258 if ((fdtol->fdl_leader->p_flag &
2259 P_ADVLOCK) == 0)
2260 continue;
2261 fdtol->fdl_holdcount++;
2262 lf.l_whence = SEEK_SET;
2263 lf.l_start = 0;
2264 lf.l_len = 0;
2265 lf.l_type = F_UNLCK;
2266 vp = (struct vnode *)fp->f_data;
2267 (void) VOP_ADVLOCK(vp,
661fc1a0 2268 (caddr_t)fdtol->fdl_leader,
984263bc
MD
2269 F_UNLCK, &lf, F_POSIX);
2270 fdtol->fdl_holdcount--;
2271 if (fdtol->fdl_holdcount == 0 &&
2272 fdtol->fdl_wakeup != 0) {
2273 fdtol->fdl_wakeup = 0;
2274 wakeup(fdtol);
2275 }
2276 }
2277 }
7749886d 2278 rel_mplock();
984263bc 2279 }
9f87144f 2280 return (fdrop(fp));
984263bc
MD
2281}
2282
85fceac1
MD
2283/*
2284 * MPSAFE
2285 *
2286 * fhold() can only be called if f_count is already at least 1 (i.e. the
2287 * caller of fhold() already has a reference to the file pointer in some
5b287bba
MD
2288 * manner or other).
2289 *
bc1eb676
MD
2290 * f_count is not spin-locked. Instead, atomic ops are used for
2291 * incrementing, decrementing, and handling the 1->0 transition.
85fceac1
MD
2292 */
2293void
2294fhold(struct file *fp)
2295{
2296 atomic_add_int(&fp->f_count, 1);
2297}
2298
2299/*
bc1eb676 2300 * fdrop() - drop a reference to a descriptor
85fceac1 2301 *
5b287bba 2302 * MPALMOSTSAFE - acquires mplock for final close sequence
85fceac1 2303 */
984263bc 2304int
9f87144f 2305fdrop(struct file *fp)
984263bc
MD
2306{
2307 struct flock lf;
2308 struct vnode *vp;
2309 int error;
2310
bc1eb676
MD
2311 /*
2312 * A combined fetch and subtract is needed to properly detect
2313 * 1->0 transitions, otherwise two cpus dropping from a ref
2314 * count of 2 might both try to run the 1->0 code.
2315 */
2316 if (atomic_fetchadd_int(&fp->f_count, -1) > 1)
984263bc 2317 return (0);
85fceac1 2318
5b287bba
MD
2319 get_mplock();
2320
85fceac1
MD
2321 /*
2322 * The last reference has gone away, we own the fp structure free
2323 * and clear.
2324 */
984263bc
MD
2325 if (fp->f_count < 0)
2326 panic("fdrop: count < 0");
7749886d
MD
2327 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE &&
2328 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS)
2329 ) {
984263bc
MD
2330 lf.l_whence = SEEK_SET;
2331 lf.l_start = 0;
2332 lf.l_len = 0;
2333 lf.l_type = F_UNLCK;
2334 vp = (struct vnode *)fp->f_data;
71c18fe3 2335 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0);
984263bc
MD
2336 }
2337 if (fp->f_ops != &badfileops)
87de5057 2338 error = fo_close(fp);
984263bc
MD
2339 else
2340 error = 0;
2341 ffree(fp);
5b287bba 2342 rel_mplock();
984263bc
MD
2343 return (error);
2344}
2345
2346/*
2347 * Apply an advisory lock on a file descriptor.
2348 *
2349 * Just attempt to get a record lock of the requested type on
2350 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
2351 */
984263bc 2352int
753fd850 2353sys_flock(struct flock_args *uap)
984263bc 2354{
41c20dac 2355 struct proc *p = curproc;
41c20dac 2356 struct file *fp;
984263bc
MD
2357 struct vnode *vp;
2358 struct flock lf;
5b287bba 2359 int error;
984263bc 2360
5b287bba 2361 if ((fp = holdfp(p->p_fd, uap->fd, -1)) == NULL)
984263bc 2362 return (EBADF);
5b287bba
MD
2363 if (fp->f_type != DTYPE_VNODE) {
2364 error = EOPNOTSUPP;
2365 goto done;
2366 }
984263bc
MD
2367 vp = (struct vnode *)fp->f_data;
2368 lf.l_whence = SEEK_SET;
2369 lf.l_start = 0;
2370 lf.l_len = 0;
2371 if (uap->how & LOCK_UN) {
2372 lf.l_type = F_UNLCK;
2373 fp->f_flag &= ~FHASLOCK;
5b287bba
MD
2374 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0);
2375 goto done;
984263bc
MD
2376 }
2377 if (uap->how & LOCK_EX)
2378 lf.l_type = F_WRLCK;
2379 else if (uap->how & LOCK_SH)
2380 lf.l_type = F_RDLCK;
5b287bba
MD
2381 else {
2382 error = EBADF;
2383 goto done;
2384 }
984263bc
MD
2385 fp->f_flag |= FHASLOCK;
2386 if (uap->how & LOCK_NB)
5b287bba
MD
2387 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0);
2388 else
2389 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT);
2390done:
2391 fdrop(fp);
2392 return (error);
984263bc
MD
2393}
2394
2395/*
2396 * File Descriptor pseudo-device driver (/dev/fd/).
2397 *
2398 * Opening minor device N dup()s the file (if any) connected to file
2399 * descriptor N belonging to the calling process. Note that this driver
2400 * consists of only the ``open()'' routine, because all subsequent
2401 * references to this file will be direct to the other driver.
2402 */
2403/* ARGSUSED */
2404static int
fef8985e 2405fdopen(struct dev_open_args *ap)
984263bc 2406{
fef8985e
MD
2407 thread_t td = curthread;
2408
fbfe4e7d 2409 KKASSERT(td->td_lwp != NULL);
984263bc
MD
2410
2411 /*
fbfe4e7d 2412 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the
984263bc
MD
2413 * the file descriptor being sought for duplication. The error
2414 * return ensures that the vnode for this device will be released
2415 * by vn_open. Open will detect this special error and take the
2416 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
2417 * will simply report the error.
2418 */
fef8985e 2419 td->td_lwp->lwp_dupfd = minor(ap->a_head.a_dev);
984263bc
MD
2420 return (ENODEV);
2421}
2422
2423/*
259b8ea0
MD
2424 * The caller has reserved the file descriptor dfd for us. On success we
2425 * must fsetfd() it. On failure the caller will clean it up.
5b287bba
MD
2426 *
2427 * NOT MPSAFE - isn't getting spinlocks, possibly other things
984263bc
MD
2428 */
2429int
259b8ea0 2430dupfdopen(struct proc *p, int dfd, int sfd, int mode, int error)
984263bc 2431{
259b8ea0 2432 struct filedesc *fdp = p->p_fd;
41c20dac 2433 struct file *wfp;
259b8ea0 2434 struct file *xfp;
ea8f324c 2435 int werror;
984263bc 2436
259b8ea0 2437 if ((wfp = holdfp(fdp, sfd, -1)) == NULL)
984263bc 2438 return (EBADF);
984263bc 2439
ea8f324c
MD
2440 /*
2441 * Close a revoke/dup race. Duping a descriptor marked as revoked
2442 * will dup a dummy descriptor instead of the real one.
2443 */
2444 if (wfp->f_flag & FREVOKED) {
2445 kprintf("Warning: attempt to dup() a revoked descriptor\n");
2446 fdrop(wfp);
2447 wfp = NULL;
2448 werror = falloc(NULL, &wfp, NULL);
2449 if (werror)
2450 return (werror);
2451 }
2452
984263bc
MD
2453 /*
2454 * There are two cases of interest here.
2455 *
259b8ea0 2456 * For ENODEV simply dup sfd to file descriptor dfd and return.
984263bc 2457 *
259b8ea0
MD
2458 * For ENXIO steal away the file structure from sfd and store it
2459 * dfd. sfd is effectively closed by this operation.
984263bc
MD
2460 *
2461 * Any other error code is just returned.
2462 */
2463 switch (error) {
2464 case ENODEV:
2465 /*
2466 * Check that the mode the file is being opened for is a
2467 * subset of the mode of the existing descriptor.
2468 */
ea8f324c
MD
2469 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
2470 error = EACCES;
2471 break;
2472 }
259b8ea0
MD
2473 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags;
2474 fsetfd(p, wfp, dfd);
2475 error = 0;
2476 break;
984263bc
MD
2477 case ENXIO:
2478 /*
2479 * Steal away the file pointer from dfd, and stuff it into indx.
2480 */
259b8ea0
MD
2481 fdp->fd_files[dfd].fileflags = fdp->fd_files[sfd].fileflags;
2482 fsetfd(p, wfp, dfd);
5b287bba 2483 if ((xfp = funsetfd_locked(fdp, sfd)) != NULL)
259b8ea0 2484 fdrop(xfp);
259b8ea0
MD
2485 error = 0;
2486 break;
984263bc 2487 default:
259b8ea0 2488 break;
984263bc 2489 }
259b8ea0
MD
2490 fdrop(wfp);
2491 return (error);
984263bc
MD
2492}
2493
5b287bba
MD
2494/*
2495 * NOT MPSAFE - I think these refer to a common file descriptor table
2496 * and we need to spinlock that to link fdtol in.
2497 */
984263bc
MD
2498struct filedesc_to_leader *
2499filedesc_to_leader_alloc(struct filedesc_to_leader *old,
2500 struct proc *leader)
2501{
2502 struct filedesc_to_leader *fdtol;
2503
77652cad 2504 fdtol = kmalloc(sizeof(struct filedesc_to_leader),
7bf8660a 2505 M_FILEDESC_TO_LEADER, M_WAITOK);
984263bc
MD
2506 fdtol->fdl_refcount = 1;
2507 fdtol->fdl_holdcount = 0;
2508 fdtol->fdl_wakeup = 0;
2509 fdtol->fdl_leader = leader;
2510 if (old != NULL) {
2511 fdtol->fdl_next = old->fdl_next;
2512 fdtol->fdl_prev = old;
2513 old->fdl_next = fdtol;
2514 fdtol->fdl_next->fdl_prev = fdtol;
2515 } else {
2516 fdtol->fdl_next = fdtol;
2517 fdtol->fdl_prev = fdtol;
2518 }
2519 return fdtol;
2520}
2521
2dd63755
MD
2522/*
2523 * Scan all file pointers in the system. The callback is made with
ea8f324c 2524 * the master list spinlock held exclusively.
2dd63755
MD
2525 *
2526 * MPSAFE
2dd63755
MD
2527 */
2528void
2529allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data)
2530{
2531 struct file *fp;
2532 int res;
2533
2534 spin_lock_wr(&filehead_spin);
2535 LIST_FOREACH(fp, &filehead, f_list) {
2dd63755 2536 res = callback(fp, data);
2dd63755
MD
2537 if (res < 0)
2538 break;
2539 }
2540 spin_unlock_wr(&filehead_spin);
2541}
2542
984263bc
MD
2543/*
2544 * Get file structures.
5b287bba
MD
2545 *
2546 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe)
984263bc 2547 */
8fa76237
MD
2548
2549struct sysctl_kern_file_info {
2550 int count;
2551 int error;
2552 struct sysctl_req *req;
2553};
2554
2555static int sysctl_kern_file_callback(struct proc *p, void *data);
2556
984263bc
MD
2557static int
2558sysctl_kern_file(SYSCTL_HANDLER_ARGS)
2559{
8fa76237 2560 struct sysctl_kern_file_info info;
984263bc
MD
2561
2562 /*
7b124c9f
JS
2563 * Note: because the number of file descriptors is calculated
2564 * in different ways for sizing vs returning the data,
2565 * there is information leakage from the first loop. However,
2566 * it is of a similar order of magnitude to the leakage from
2567 * global system statistics such as kern.openfiles.
6d132b4d
MD
2568 *
2569 * When just doing a count, note that we cannot just count
2570 * the elements and add f_count via the filehead list because
2571 * threaded processes share their descriptor table and f_count might
2572 * still be '1' in that case.
e38910da
MD
2573 *
2574 * Since the SYSCTL op can block, we must hold the process to
2575 * prevent it being ripped out from under us either in the
2576 * file descriptor loop or in the greater LIST_FOREACH. The
2577 * process may be in varying states of disrepair. If the process
2578 * is in SZOMB we may have caught it just as it is being removed
2579 * from the allproc list, we must skip it in that case to maintain
2580 * an unbroken chain through the allproc list.
984263bc 2581 */
8fa76237
MD
2582 info.count = 0;
2583 info.error = 0;
2584 info.req = req;
2585 allproc_scan(sysctl_kern_file_callback, &info);
6d132b4d
MD
2586
2587 /*
2588 * When just calculating the size, overestimate a bit to try to
2589 * prevent system activity from causing the buffer-fill call
2590 * to fail later on.
2591 */
2592 if (req->oldptr == NULL) {
8fa76237
MD
2593 info.count = (info.count + 16) + (info.count / 10);
2594 info.error = SYSCTL_OUT(req, NULL,
2595 info.count * sizeof(struct kinfo_file));
6d132b4d 2596 }
8fa76237
MD
2597 return (info.error);
2598}
2599
2600static int
2601sysctl_kern_file_callback(struct proc *p, void *data)
2602{
2603 struct sysctl_kern_file_info *info = data;
2604 struct kinfo_file kf;
2605 struct filedesc *fdp;
2606 struct file *fp;
2607 uid_t uid;
2608 int n;
2609
416d05d7 2610 if (p->p_stat == SIDL || p->p_stat == SZOMB)
8fa76237
MD
2611 return(0);
2612 if (!PRISON_CHECK(info->req->td->td_proc->p_ucred, p->p_ucred) != 0)
2613 return(0);
0a4a9c77
MD
2614
2615 /*
2616 * Softref the fdp to prevent it from being destroyed
2617 */
2618 spin_lock_wr(&p->p_spin);
2619 if ((fdp = p->p_fd) == NULL) {
2620 spin_unlock_wr(&p->p_spin);
8fa76237 2621 return(0);
0a4a9c77
MD
2622 }
2623 atomic_add_int(&fdp->fd_softrefs, 1);
2624 spin_unlock_wr(&p->p_spin);
2625
2626 /*
2627 * The fdp's own spinlock prevents the contents from being
2628 * modified.
2629 */
8fa76237
MD
2630 spin_lock_rd(&fdp->fd_spin);
2631 for (n = 0; n < fdp->fd_nfiles; ++n) {
2632 if ((fp = fdp->fd_files[n].fp) == NULL)
2633 continue;
2634 if (info->req->oldptr == NULL) {
2635 ++info->count;
2636 } else {
2637 uid = p->p_ucred ? p->p_ucred->cr_uid : -1;
2638 kcore_make_file(&kf, fp, p->p_pid, uid, n);
2639 spin_unlock_rd(&fdp->fd_spin);
2640 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf));
2641 spin_lock_rd(&fdp->fd_spin);
2642 if (info->error)
2643 break;
2644 }
2645 }
2646 spin_unlock_rd(&fdp->fd_spin);
0a4a9c77 2647 atomic_subtract_int(&fdp->fd_softrefs, 1);
8fa76237
MD
2648 if (info->error)
2649 return(-1);
2650 return(0);
984263bc
MD
2651}
2652
2653SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
2654 0, 0, sysctl_kern_file, "S,file", "Entire file table");
2655
2656SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
2657 &maxfilesperproc, 0, "Maximum files allowed open per process");
2658
2659SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
2660 &maxfiles, 0, "Maximum number of files");
2661
60ee93b9
MD
2662SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW,
2663 &maxfilesrootres, 0, "Descriptors reserved for root use");
2664
984263bc
MD
2665SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
2666 &nfiles, 0, "System-wide number of open files");
2667
2668static void
2669fildesc_drvinit(void *unused)
2670{
2671 int fd;
2672
fef8985e 2673 dev_ops_add(&fildesc_ops, 0, 0);
e4c9c0c8 2674 for (fd = 0; fd < NUMFDESC; fd++) {
fef8985e 2675 make_dev(&fildesc_ops, fd,
984263bc 2676 UID_BIN, GID_BIN, 0666, "fd/%d", fd);
e4c9c0c8 2677 }
fef8985e
MD
2678 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin");
2679 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout");
2680 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr");
984263bc
MD
2681}
2682
d9b2033e
MD
2683/*
2684 * MPSAFE
2685 */
984263bc 2686struct fileops badfileops = {
b2d248cb
MD
2687 .fo_read = badfo_readwrite,
2688 .fo_write = badfo_readwrite,
2689 .fo_ioctl = badfo_ioctl,
2690 .fo_poll = badfo_poll,
2691 .fo_kqfilter = badfo_kqfilter,
2692 .fo_stat = badfo_stat,
2693 .fo_close = badfo_close,
2694 .fo_shutdown = badfo_shutdown
984263bc
MD
2695};
2696
d9b2033e
MD
2697/*
2698 * MPSAFE
2699 */
984263bc 2700static int
dadab5e9
MD
2701badfo_readwrite(
2702 struct file *fp,
2703 struct uio *uio,
2704 struct ucred *cred,
87de5057 2705 int flags
dadab5e9 2706) {
984263bc
MD
2707 return (EBADF);
2708}
2709
d9b2033e
MD
2710/*
2711 * MPSAFE
2712 */
984263bc 2713static int
87de5057 2714badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *cred)
984263bc 2715{
984263bc
MD
2716 return (EBADF);
2717}
2718
d9b2033e
MD
2719/*
2720 * MPSAFE
2721 */
984263bc 2722static int
87de5057 2723badfo_poll(struct file *fp, int events, struct ucred *cred)
984263bc 2724{
984263bc
MD
2725 return (0);
2726}
2727
d9b2033e
MD
2728/*
2729 * MPSAFE
2730 */
984263bc 2731static int
dadab5e9 2732badfo_kqfilter(struct file *fp, struct knote *kn)
984263bc 2733{
984263bc
MD
2734 return (0);
2735}
2736
2737static int
87de5057 2738badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred)
984263bc 2739{
984263bc
MD
2740 return (EBADF);
2741}
2742
d9b2033e
MD
2743/*
2744 * MPSAFE
2745 */
984263bc 2746static int
87de5057 2747badfo_close(struct file *fp)
984263bc 2748{
984263bc
MD
2749 return (EBADF);
2750}
2751
d9b2033e
MD
2752/*
2753 * MPSAFE
2754 */
004d2de5 2755static int
87de5057 2756badfo_shutdown(struct file *fp, int how)
004d2de5
MD
2757{
2758 return (EBADF);
2759}
2760
d9b2033e
MD
2761/*
2762 * MPSAFE
2763 */
004d2de5 2764int
87de5057 2765nofo_shutdown(struct file *fp, int how)
004d2de5
MD
2766{
2767 return (EOPNOTSUPP);
2768}
2769
984263bc
MD
2770SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
2771 fildesc_drvinit,NULL)