xref: /netbsd-src/sys/kern/sys_generic.c (revision 9573504567626934c7ee01c7dce0c4bb1dfe7403)
1 /*	$NetBSD: sys_generic.c,v 1.21 1995/10/07 06:28:34 mycroft Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. All advertising materials mentioning features or use of this software
21  *    must display the following acknowledgement:
22  *	This product includes software developed by the University of
23  *	California, Berkeley and its contributors.
24  * 4. Neither the name of the University nor the names of its contributors
25  *    may be used to endorse or promote products derived from this software
26  *    without specific prior written permission.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38  * SUCH DAMAGE.
39  *
40  *	@(#)sys_generic.c	8.5 (Berkeley) 1/21/94
41  */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/filedesc.h>
46 #include <sys/ioctl.h>
47 #include <sys/file.h>
48 #include <sys/proc.h>
49 #include <sys/socketvar.h>
50 #include <sys/uio.h>
51 #include <sys/kernel.h>
52 #include <sys/stat.h>
53 #include <sys/malloc.h>
54 #ifdef KTRACE
55 #include <sys/ktrace.h>
56 #endif
57 
58 #include <sys/mount.h>
59 #include <sys/syscallargs.h>
60 
61 /*
62  * Read system call.
63  */
64 /* ARGSUSED */
65 sys_read(p, v, retval)
66 	struct proc *p;
67 	void *v;
68 	register_t *retval;
69 {
70 	register struct sys_read_args /* {
71 		syscallarg(int) fd;
72 		syscallarg(char *) buf;
73 		syscallarg(u_int) nbyte;
74 	} */ *uap = v;
75 	register struct file *fp;
76 	register struct filedesc *fdp = p->p_fd;
77 	struct uio auio;
78 	struct iovec aiov;
79 	long cnt, error = 0;
80 #ifdef KTRACE
81 	struct iovec ktriov;
82 #endif
83 
84 	if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
85 	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
86 	    (fp->f_flag & FREAD) == 0)
87 		return (EBADF);
88 	aiov.iov_base = (caddr_t)SCARG(uap, buf);
89 	aiov.iov_len = SCARG(uap, nbyte);
90 	auio.uio_iov = &aiov;
91 	auio.uio_iovcnt = 1;
92 	auio.uio_resid = SCARG(uap, nbyte);
93 	auio.uio_rw = UIO_READ;
94 	auio.uio_segflg = UIO_USERSPACE;
95 	auio.uio_procp = p;
96 	if (auio.uio_resid < 0)
97 		return EINVAL;
98 #ifdef KTRACE
99 	/*
100 	 * if tracing, save a copy of iovec
101 	 */
102 	if (KTRPOINT(p, KTR_GENIO))
103 		ktriov = aiov;
104 #endif
105 	cnt = SCARG(uap, nbyte);
106 	if (error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred))
107 		if (auio.uio_resid != cnt && (error == ERESTART ||
108 		    error == EINTR || error == EWOULDBLOCK))
109 			error = 0;
110 	cnt -= auio.uio_resid;
111 #ifdef KTRACE
112 	if (KTRPOINT(p, KTR_GENIO) && error == 0)
113 		ktrgenio(p->p_tracep, SCARG(uap, fd), UIO_READ, &ktriov,
114 		    cnt, error);
115 #endif
116 	*retval = cnt;
117 	return (error);
118 }
119 
120 /*
121  * Scatter read system call.
122  */
123 sys_readv(p, v, retval)
124 	struct proc *p;
125 	void *v;
126 	register_t *retval;
127 {
128 	register struct sys_readv_args /* {
129 		syscallarg(int) fd;
130 		syscallarg(struct iovec *) iovp;
131 		syscallarg(u_int) iovcnt;
132 	} */ *uap = v;
133 	register struct file *fp;
134 	register struct filedesc *fdp = p->p_fd;
135 	struct uio auio;
136 	register struct iovec *iov;
137 	struct iovec *needfree;
138 	struct iovec aiov[UIO_SMALLIOV];
139 	long i, cnt, error = 0;
140 	u_int iovlen;
141 #ifdef KTRACE
142 	struct iovec *ktriov = NULL;
143 #endif
144 
145 	if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
146 	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
147 	    (fp->f_flag & FREAD) == 0)
148 		return (EBADF);
149 	/* note: can't use iovlen until iovcnt is validated */
150 	iovlen = SCARG(uap, iovcnt) * sizeof (struct iovec);
151 	if (SCARG(uap, iovcnt) > UIO_SMALLIOV) {
152 		if (SCARG(uap, iovcnt) > UIO_MAXIOV)
153 			return (EINVAL);
154 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
155 		needfree = iov;
156 	} else {
157 		iov = aiov;
158 		needfree = NULL;
159 	}
160 	auio.uio_iov = iov;
161 	auio.uio_iovcnt = SCARG(uap, iovcnt);
162 	auio.uio_rw = UIO_READ;
163 	auio.uio_segflg = UIO_USERSPACE;
164 	auio.uio_procp = p;
165 	if (error = copyin((caddr_t)SCARG(uap, iovp), (caddr_t)iov, iovlen))
166 		goto done;
167 	auio.uio_resid = 0;
168 	for (i = 0; i < SCARG(uap, iovcnt); i++) {
169 		if (iov->iov_len < 0) {
170 			error = EINVAL;
171 			goto done;
172 		}
173 		auio.uio_resid += iov->iov_len;
174 		if (auio.uio_resid < 0) {
175 			error = EINVAL;
176 			goto done;
177 		}
178 		iov++;
179 	}
180 #ifdef KTRACE
181 	/*
182 	 * if tracing, save a copy of iovec
183 	 */
184 	if (KTRPOINT(p, KTR_GENIO))  {
185 		MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
186 		bcopy((caddr_t)auio.uio_iov, (caddr_t)ktriov, iovlen);
187 	}
188 #endif
189 	cnt = auio.uio_resid;
190 	if (error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred))
191 		if (auio.uio_resid != cnt && (error == ERESTART ||
192 		    error == EINTR || error == EWOULDBLOCK))
193 			error = 0;
194 	cnt -= auio.uio_resid;
195 #ifdef KTRACE
196 	if (ktriov != NULL) {
197 		if (error == 0)
198 			ktrgenio(p->p_tracep, SCARG(uap, fd), UIO_READ, ktriov,
199 			    cnt, error);
200 		FREE(ktriov, M_TEMP);
201 	}
202 #endif
203 	*retval = cnt;
204 done:
205 	if (needfree)
206 		FREE(needfree, M_IOV);
207 	return (error);
208 }
209 
210 /*
211  * Write system call
212  */
213 sys_write(p, v, retval)
214 	struct proc *p;
215 	void *v;
216 	register_t *retval;
217 {
218 	register struct sys_write_args /* {
219 		syscallarg(int) fd;
220 		syscallarg(char *) buf;
221 		syscallarg(u_int) nbyte;
222 	} */ *uap = v;
223 	register struct file *fp;
224 	register struct filedesc *fdp = p->p_fd;
225 	struct uio auio;
226 	struct iovec aiov;
227 	long cnt, error = 0;
228 #ifdef KTRACE
229 	struct iovec ktriov;
230 #endif
231 
232 	if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
233 	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
234 	    (fp->f_flag & FWRITE) == 0)
235 		return (EBADF);
236 	aiov.iov_base = (caddr_t)SCARG(uap, buf);
237 	aiov.iov_len = SCARG(uap, nbyte);
238 	auio.uio_iov = &aiov;
239 	auio.uio_iovcnt = 1;
240 	auio.uio_resid = SCARG(uap, nbyte);
241 	auio.uio_rw = UIO_WRITE;
242 	auio.uio_segflg = UIO_USERSPACE;
243 	auio.uio_procp = p;
244 	if (auio.uio_resid < 0)
245 		return EINVAL;
246 #ifdef KTRACE
247 	/*
248 	 * if tracing, save a copy of iovec
249 	 */
250 	if (KTRPOINT(p, KTR_GENIO))
251 		ktriov = aiov;
252 #endif
253 	cnt = SCARG(uap, nbyte);
254 	if (error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred)) {
255 		if (auio.uio_resid != cnt && (error == ERESTART ||
256 		    error == EINTR || error == EWOULDBLOCK))
257 			error = 0;
258 		if (error == EPIPE)
259 			psignal(p, SIGPIPE);
260 	}
261 	cnt -= auio.uio_resid;
262 #ifdef KTRACE
263 	if (KTRPOINT(p, KTR_GENIO) && error == 0)
264 		ktrgenio(p->p_tracep, SCARG(uap, fd), UIO_WRITE,
265 		    &ktriov, cnt, error);
266 #endif
267 	*retval = cnt;
268 	return (error);
269 }
270 
271 /*
272  * Gather write system call
273  */
274 sys_writev(p, v, retval)
275 	struct proc *p;
276 	void *v;
277 	register_t *retval;
278 {
279 	register struct sys_writev_args /* {
280 		syscallarg(int) fd;
281 		syscallarg(struct iovec *) iovp;
282 		syscallarg(u_int) iovcnt;
283 	} */ *uap = v;
284 	register struct file *fp;
285 	register struct filedesc *fdp = p->p_fd;
286 	struct uio auio;
287 	register struct iovec *iov;
288 	struct iovec *needfree;
289 	struct iovec aiov[UIO_SMALLIOV];
290 	long i, cnt, error = 0;
291 	u_int iovlen;
292 #ifdef KTRACE
293 	struct iovec *ktriov = NULL;
294 #endif
295 
296 	if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
297 	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
298 	    (fp->f_flag & FWRITE) == 0)
299 		return (EBADF);
300 	/* note: can't use iovlen until iovcnt is validated */
301 	iovlen = SCARG(uap, iovcnt) * sizeof (struct iovec);
302 	if (SCARG(uap, iovcnt) > UIO_SMALLIOV) {
303 		if (SCARG(uap, iovcnt) > UIO_MAXIOV)
304 			return (EINVAL);
305 		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
306 		needfree = iov;
307 	} else {
308 		iov = aiov;
309 		needfree = NULL;
310 	}
311 	auio.uio_iov = iov;
312 	auio.uio_iovcnt = SCARG(uap, iovcnt);
313 	auio.uio_rw = UIO_WRITE;
314 	auio.uio_segflg = UIO_USERSPACE;
315 	auio.uio_procp = p;
316 	if (error = copyin((caddr_t)SCARG(uap, iovp), (caddr_t)iov, iovlen))
317 		goto done;
318 	auio.uio_resid = 0;
319 	for (i = 0; i < SCARG(uap, iovcnt); i++) {
320 		if (iov->iov_len < 0) {
321 			error = EINVAL;
322 			goto done;
323 		}
324 		auio.uio_resid += iov->iov_len;
325 		if (auio.uio_resid < 0) {
326 			error = EINVAL;
327 			goto done;
328 		}
329 		iov++;
330 	}
331 #ifdef KTRACE
332 	/*
333 	 * if tracing, save a copy of iovec
334 	 */
335 	if (KTRPOINT(p, KTR_GENIO))  {
336 		MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
337 		bcopy((caddr_t)auio.uio_iov, (caddr_t)ktriov, iovlen);
338 	}
339 #endif
340 	cnt = auio.uio_resid;
341 	if (error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred)) {
342 		if (auio.uio_resid != cnt && (error == ERESTART ||
343 		    error == EINTR || error == EWOULDBLOCK))
344 			error = 0;
345 		if (error == EPIPE)
346 			psignal(p, SIGPIPE);
347 	}
348 	cnt -= auio.uio_resid;
349 #ifdef KTRACE
350 	if (ktriov != NULL) {
351 		if (error == 0)
352 			ktrgenio(p->p_tracep, SCARG(uap, fd), UIO_WRITE,
353 				ktriov, cnt, error);
354 		FREE(ktriov, M_TEMP);
355 	}
356 #endif
357 	*retval = cnt;
358 done:
359 	if (needfree)
360 		FREE(needfree, M_IOV);
361 	return (error);
362 }
363 
364 /*
365  * Ioctl system call
366  */
367 /* ARGSUSED */
368 sys_ioctl(p, v, retval)
369 	struct proc *p;
370 	void *v;
371 	register_t *retval;
372 {
373 	register struct sys_ioctl_args /* {
374 		syscallarg(int) fd;
375 		syscallarg(u_long) com;
376 		syscallarg(caddr_t) data;
377 	} */ *uap = v;
378 	register struct file *fp;
379 	register struct filedesc *fdp;
380 	register u_long com;
381 	register int error;
382 	register u_int size;
383 	caddr_t data, memp;
384 	int tmp;
385 #define STK_PARAMS	128
386 	char stkbuf[STK_PARAMS];
387 
388 	fdp = p->p_fd;
389 	if ((u_int)SCARG(uap, fd) >= fdp->fd_nfiles ||
390 	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL)
391 		return (EBADF);
392 
393 	if ((fp->f_flag & (FREAD | FWRITE)) == 0)
394 		return (EBADF);
395 
396 	switch (com = SCARG(uap, com)) {
397 	case FIONCLEX:
398 		fdp->fd_ofileflags[SCARG(uap, fd)] &= ~UF_EXCLOSE;
399 		return (0);
400 	case FIOCLEX:
401 		fdp->fd_ofileflags[SCARG(uap, fd)] |= UF_EXCLOSE;
402 		return (0);
403 	}
404 
405 	/*
406 	 * Interpret high order word to find amount of data to be
407 	 * copied to/from the user's address space.
408 	 */
409 	size = IOCPARM_LEN(com);
410 	if (size > IOCPARM_MAX)
411 		return (ENOTTY);
412 	memp = NULL;
413 	if (size > sizeof (stkbuf)) {
414 		memp = (caddr_t)malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
415 		data = memp;
416 	} else
417 		data = stkbuf;
418 	if (com&IOC_IN) {
419 		if (size) {
420 			error = copyin(SCARG(uap, data), data, (u_int)size);
421 			if (error) {
422 				if (memp)
423 					free(memp, M_IOCTLOPS);
424 				return (error);
425 			}
426 		} else
427 			*(caddr_t *)data = SCARG(uap, data);
428 	} else if ((com&IOC_OUT) && size)
429 		/*
430 		 * Zero the buffer so the user always
431 		 * gets back something deterministic.
432 		 */
433 		bzero(data, size);
434 	else if (com&IOC_VOID)
435 		*(caddr_t *)data = SCARG(uap, data);
436 
437 	switch (com) {
438 
439 	case FIONBIO:
440 		if (tmp = *(int *)data)
441 			fp->f_flag |= FNONBLOCK;
442 		else
443 			fp->f_flag &= ~FNONBLOCK;
444 		error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
445 		break;
446 
447 	case FIOASYNC:
448 		if (tmp = *(int *)data)
449 			fp->f_flag |= FASYNC;
450 		else
451 			fp->f_flag &= ~FASYNC;
452 		error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
453 		break;
454 
455 	case FIOSETOWN:
456 		tmp = *(int *)data;
457 		if (fp->f_type == DTYPE_SOCKET) {
458 			((struct socket *)fp->f_data)->so_pgid = tmp;
459 			error = 0;
460 			break;
461 		}
462 		if (tmp <= 0) {
463 			tmp = -tmp;
464 		} else {
465 			struct proc *p1 = pfind(tmp);
466 			if (p1 == 0) {
467 				error = ESRCH;
468 				break;
469 			}
470 			tmp = p1->p_pgrp->pg_id;
471 		}
472 		error = (*fp->f_ops->fo_ioctl)
473 			(fp, (int)TIOCSPGRP, (caddr_t)&tmp, p);
474 		break;
475 
476 	case FIOGETOWN:
477 		if (fp->f_type == DTYPE_SOCKET) {
478 			error = 0;
479 			*(int *)data = ((struct socket *)fp->f_data)->so_pgid;
480 			break;
481 		}
482 		error = (*fp->f_ops->fo_ioctl)(fp, TIOCGPGRP, data, p);
483 		*(int *)data = -*(int *)data;
484 		break;
485 
486 	default:
487 		error = (*fp->f_ops->fo_ioctl)(fp, com, data, p);
488 		/*
489 		 * Copy any data to user, size was
490 		 * already set and checked above.
491 		 */
492 		if (error == 0 && (com&IOC_OUT) && size)
493 			error = copyout(data, SCARG(uap, data), (u_int)size);
494 		break;
495 	}
496 	if (memp)
497 		free(memp, M_IOCTLOPS);
498 	return (error);
499 }
500 
501 int	selwait, nselcoll;
502 
503 /*
504  * Select system call.
505  */
506 sys_select(p, v, retval)
507 	register struct proc *p;
508 	void *v;
509 	register_t *retval;
510 {
511 	register struct sys_select_args /* {
512 		syscallarg(u_int) nd;
513 		syscallarg(fd_set *) in;
514 		syscallarg(fd_set *) ou;
515 		syscallarg(fd_set *) ex;
516 		syscallarg(struct timeval *) tv;
517 	} */ *uap = v;
518 	fd_set ibits[3], obits[3];
519 	struct timeval atv;
520 	int s, ncoll, error = 0, timo;
521 	u_int ni;
522 
523 	bzero((caddr_t)ibits, sizeof(ibits));
524 	bzero((caddr_t)obits, sizeof(obits));
525 	if (SCARG(uap, nd) > FD_SETSIZE)
526 		return (EINVAL);
527 	if (SCARG(uap, nd) > p->p_fd->fd_nfiles) {
528 		/* forgiving; slightly wrong */
529 		SCARG(uap, nd) = p->p_fd->fd_nfiles;
530 	}
531 	ni = howmany(SCARG(uap, nd), NFDBITS) * sizeof(fd_mask);
532 
533 #define	getbits(name, x) \
534 	if (SCARG(uap, name) && (error = copyin((caddr_t)SCARG(uap, name), \
535 	    (caddr_t)&ibits[x], ni))) \
536 		goto done;
537 	getbits(in, 0);
538 	getbits(ou, 1);
539 	getbits(ex, 2);
540 #undef	getbits
541 
542 	if (SCARG(uap, tv)) {
543 		error = copyin((caddr_t)SCARG(uap, tv), (caddr_t)&atv,
544 			sizeof (atv));
545 		if (error)
546 			goto done;
547 		if (itimerfix(&atv)) {
548 			error = EINVAL;
549 			goto done;
550 		}
551 		s = splclock();
552 		timeradd(&atv, &time, &atv);
553 		timo = hzto(&atv);
554 		/*
555 		 * Avoid inadvertently sleeping forever.
556 		 */
557 		if (timo == 0)
558 			timo = 1;
559 		splx(s);
560 	} else
561 		timo = 0;
562 retry:
563 	ncoll = nselcoll;
564 	p->p_flag |= P_SELECT;
565 	error = selscan(p, ibits, obits, SCARG(uap, nd), retval);
566 	if (error || *retval)
567 		goto done;
568 	s = splhigh();
569 	/* this should be timercmp(&time, &atv, >=) */
570 	if (SCARG(uap, tv) && (time.tv_sec > atv.tv_sec ||
571 	    time.tv_sec == atv.tv_sec && time.tv_usec >= atv.tv_usec)) {
572 		splx(s);
573 		goto done;
574 	}
575 	if ((p->p_flag & P_SELECT) == 0 || nselcoll != ncoll) {
576 		splx(s);
577 		goto retry;
578 	}
579 	p->p_flag &= ~P_SELECT;
580 	error = tsleep((caddr_t)&selwait, PSOCK | PCATCH, "select", timo);
581 	splx(s);
582 	if (error == 0)
583 		goto retry;
584 done:
585 	p->p_flag &= ~P_SELECT;
586 	/* select is not restarted after signals... */
587 	if (error == ERESTART)
588 		error = EINTR;
589 	if (error == EWOULDBLOCK)
590 		error = 0;
591 #define	putbits(name, x) \
592 	if (SCARG(uap, name) && (error2 = copyout((caddr_t)&obits[x], \
593 	    (caddr_t)SCARG(uap, name), ni))) \
594 		error = error2;
595 	if (error == 0) {
596 		int error2;
597 
598 		putbits(in, 0);
599 		putbits(ou, 1);
600 		putbits(ex, 2);
601 #undef putbits
602 	}
603 	return (error);
604 }
605 
606 selscan(p, ibits, obits, nfd, retval)
607 	struct proc *p;
608 	fd_set *ibits, *obits;
609 	int nfd;
610 	register_t *retval;
611 {
612 	register struct filedesc *fdp = p->p_fd;
613 	register int msk, i, j, fd;
614 	register fd_mask bits;
615 	struct file *fp;
616 	int n = 0;
617 	static int flag[3] = { FREAD, FWRITE, 0 };
618 
619 	for (msk = 0; msk < 3; msk++) {
620 		for (i = 0; i < nfd; i += NFDBITS) {
621 			bits = ibits[msk].fds_bits[i/NFDBITS];
622 			while ((j = ffs(bits)) && (fd = i + --j) < nfd) {
623 				bits &= ~(1 << j);
624 				fp = fdp->fd_ofiles[fd];
625 				if (fp == NULL)
626 					return (EBADF);
627 				if ((*fp->f_ops->fo_select)(fp, flag[msk], p)) {
628 					FD_SET(fd, &obits[msk]);
629 					n++;
630 				}
631 			}
632 		}
633 	}
634 	*retval = n;
635 	return (0);
636 }
637 
638 /*ARGSUSED*/
639 seltrue(dev, flag, p)
640 	dev_t dev;
641 	int flag;
642 	struct proc *p;
643 {
644 
645 	return (1);
646 }
647 
648 /*
649  * Record a select request.
650  */
651 void
652 selrecord(selector, sip)
653 	struct proc *selector;
654 	struct selinfo *sip;
655 {
656 	struct proc *p;
657 	pid_t mypid;
658 
659 	mypid = selector->p_pid;
660 	if (sip->si_pid == mypid)
661 		return;
662 	if (sip->si_pid && (p = pfind(sip->si_pid)) &&
663 	    p->p_wchan == (caddr_t)&selwait)
664 		sip->si_flags |= SI_COLL;
665 	else
666 		sip->si_pid = mypid;
667 }
668 
669 /*
670  * Do a wakeup when a selectable event occurs.
671  */
672 void
673 selwakeup(sip)
674 	register struct selinfo *sip;
675 {
676 	register struct proc *p;
677 	int s;
678 
679 	if (sip->si_pid == 0)
680 		return;
681 	if (sip->si_flags & SI_COLL) {
682 		nselcoll++;
683 		sip->si_flags &= ~SI_COLL;
684 		wakeup((caddr_t)&selwait);
685 	}
686 	p = pfind(sip->si_pid);
687 	sip->si_pid = 0;
688 	if (p != NULL) {
689 		s = splhigh();
690 		if (p->p_wchan == (caddr_t)&selwait) {
691 			if (p->p_stat == SSLEEP)
692 				setrunnable(p);
693 			else
694 				unsleep(p);
695 		} else if (p->p_flag & P_SELECT)
696 			p->p_flag &= ~P_SELECT;
697 		splx(s);
698 	}
699 }
700