uipc_sem.c revision 1.36 1 1.36 joerg /* $NetBSD: uipc_sem.c,v 1.36 2012/03/08 21:59:30 joerg Exp $ */
2 1.3 thorpej
3 1.3 thorpej /*-
4 1.30 rmind * Copyright (c) 2011 The NetBSD Foundation, Inc.
5 1.3 thorpej * All rights reserved.
6 1.3 thorpej *
7 1.3 thorpej * This code is derived from software contributed to The NetBSD Foundation
8 1.30 rmind * by Mindaugas Rasiukevicius.
9 1.3 thorpej *
10 1.3 thorpej * Redistribution and use in source and binary forms, with or without
11 1.3 thorpej * modification, are permitted provided that the following conditions
12 1.3 thorpej * are met:
13 1.3 thorpej * 1. Redistributions of source code must retain the above copyright
14 1.3 thorpej * notice, this list of conditions and the following disclaimer.
15 1.3 thorpej * 2. Redistributions in binary form must reproduce the above copyright
16 1.3 thorpej * notice, this list of conditions and the following disclaimer in the
17 1.3 thorpej * documentation and/or other materials provided with the distribution.
18 1.3 thorpej *
19 1.3 thorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 1.3 thorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 1.3 thorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 1.3 thorpej * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 1.3 thorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 1.3 thorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 1.3 thorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 1.3 thorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 1.3 thorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 1.3 thorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 1.3 thorpej * POSSIBILITY OF SUCH DAMAGE.
30 1.3 thorpej */
31 1.1 christos
32 1.1 christos /*
33 1.1 christos * Copyright (c) 2002 Alfred Perlstein <alfred (at) FreeBSD.org>
34 1.1 christos * All rights reserved.
35 1.1 christos *
36 1.1 christos * Redistribution and use in source and binary forms, with or without
37 1.1 christos * modification, are permitted provided that the following conditions
38 1.1 christos * are met:
39 1.1 christos * 1. Redistributions of source code must retain the above copyright
40 1.1 christos * notice, this list of conditions and the following disclaimer.
41 1.1 christos * 2. Redistributions in binary form must reproduce the above copyright
42 1.1 christos * notice, this list of conditions and the following disclaimer in the
43 1.1 christos * documentation and/or other materials provided with the distribution.
44 1.1 christos *
45 1.1 christos * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
46 1.1 christos * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47 1.1 christos * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48 1.1 christos * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
49 1.1 christos * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
50 1.1 christos * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
51 1.1 christos * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
52 1.1 christos * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
53 1.1 christos * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
54 1.1 christos * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
55 1.1 christos * SUCH DAMAGE.
56 1.1 christos */
57 1.9 lukem
58 1.30 rmind /*
59 1.30 rmind * Implementation of POSIX semaphore.
60 1.30 rmind */
61 1.30 rmind
62 1.9 lukem #include <sys/cdefs.h>
63 1.36 joerg __KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.36 2012/03/08 21:59:30 joerg Exp $");
64 1.1 christos
65 1.1 christos #include <sys/param.h>
66 1.1 christos #include <sys/kernel.h>
67 1.34 rmind
68 1.34 rmind #include <sys/atomic.h>
69 1.1 christos #include <sys/proc.h>
70 1.1 christos #include <sys/ksem.h>
71 1.1 christos #include <sys/syscall.h>
72 1.1 christos #include <sys/stat.h>
73 1.21 ad #include <sys/kmem.h>
74 1.1 christos #include <sys/fcntl.h>
75 1.30 rmind #include <sys/file.h>
76 1.30 rmind #include <sys/filedesc.h>
77 1.14 elad #include <sys/kauth.h>
78 1.27 ad #include <sys/module.h>
79 1.1 christos #include <sys/mount.h>
80 1.27 ad #include <sys/syscall.h>
81 1.1 christos #include <sys/syscallargs.h>
82 1.27 ad #include <sys/syscallvar.h>
83 1.1 christos
84 1.30 rmind MODULE(MODULE_CLASS_MISC, ksem, NULL);
85 1.30 rmind
86 1.30 rmind #define SEM_MAX_NAMELEN 14
87 1.30 rmind #define SEM_VALUE_MAX (~0U)
88 1.1 christos
89 1.30 rmind #define KS_UNLINKED 0x01
90 1.4 thorpej
91 1.30 rmind typedef struct ksem {
92 1.30 rmind LIST_ENTRY(ksem) ks_entry; /* global list entry */
93 1.30 rmind kmutex_t ks_lock; /* lock on this ksem */
94 1.30 rmind kcondvar_t ks_cv; /* condition variable */
95 1.30 rmind u_int ks_ref; /* number of references */
96 1.30 rmind u_int ks_value; /* current value */
97 1.30 rmind u_int ks_waiters; /* number of waiters */
98 1.30 rmind char * ks_name; /* name, if named */
99 1.30 rmind size_t ks_namelen; /* length of name */
100 1.30 rmind int ks_flags; /* for KS_UNLINKED */
101 1.30 rmind mode_t ks_mode; /* protection bits */
102 1.30 rmind uid_t ks_uid; /* creator uid */
103 1.30 rmind gid_t ks_gid; /* creator gid */
104 1.30 rmind } ksem_t;
105 1.30 rmind
106 1.30 rmind static kmutex_t ksem_lock __cacheline_aligned;
107 1.30 rmind static LIST_HEAD(,ksem) ksem_head __cacheline_aligned;
108 1.34 rmind static u_int nsems_total __cacheline_aligned;
109 1.30 rmind static u_int nsems __cacheline_aligned;
110 1.30 rmind
111 1.30 rmind static int ksem_sysinit(void);
112 1.30 rmind static int ksem_sysfini(bool);
113 1.30 rmind static int ksem_modcmd(modcmd_t, void *);
114 1.30 rmind static int ksem_close_fop(file_t *);
115 1.30 rmind
116 1.30 rmind static const struct fileops semops = {
117 1.30 rmind .fo_read = fbadop_read,
118 1.30 rmind .fo_write = fbadop_write,
119 1.30 rmind .fo_ioctl = fbadop_ioctl,
120 1.30 rmind .fo_fcntl = fnullop_fcntl,
121 1.30 rmind .fo_poll = fnullop_poll,
122 1.30 rmind .fo_stat = fbadop_stat,
123 1.30 rmind .fo_close = ksem_close_fop,
124 1.30 rmind .fo_kqfilter = fnullop_kqfilter,
125 1.30 rmind .fo_restart = fnullop_restart,
126 1.30 rmind };
127 1.27 ad
128 1.27 ad static const struct syscall_package ksem_syscalls[] = {
129 1.27 ad { SYS__ksem_init, 0, (sy_call_t *)sys__ksem_init },
130 1.27 ad { SYS__ksem_open, 0, (sy_call_t *)sys__ksem_open },
131 1.27 ad { SYS__ksem_unlink, 0, (sy_call_t *)sys__ksem_unlink },
132 1.27 ad { SYS__ksem_close, 0, (sy_call_t *)sys__ksem_close },
133 1.27 ad { SYS__ksem_post, 0, (sy_call_t *)sys__ksem_post },
134 1.27 ad { SYS__ksem_wait, 0, (sy_call_t *)sys__ksem_wait },
135 1.27 ad { SYS__ksem_trywait, 0, (sy_call_t *)sys__ksem_trywait },
136 1.27 ad { SYS__ksem_getvalue, 0, (sy_call_t *)sys__ksem_getvalue },
137 1.27 ad { SYS__ksem_destroy, 0, (sy_call_t *)sys__ksem_destroy },
138 1.36 joerg { SYS__ksem_timedwait, 0, (sy_call_t *)sys__ksem_timedwait },
139 1.27 ad { 0, 0, NULL },
140 1.27 ad };
141 1.1 christos
142 1.30 rmind static int
143 1.30 rmind ksem_sysinit(void)
144 1.3 thorpej {
145 1.30 rmind int error;
146 1.1 christos
147 1.30 rmind mutex_init(&ksem_lock, MUTEX_DEFAULT, IPL_NONE);
148 1.30 rmind LIST_INIT(&ksem_head);
149 1.34 rmind nsems_total = 0;
150 1.34 rmind nsems = 0;
151 1.20 ad
152 1.30 rmind error = syscall_establish(NULL, ksem_syscalls);
153 1.30 rmind if (error) {
154 1.30 rmind (void)ksem_sysfini(false);
155 1.3 thorpej }
156 1.30 rmind return error;
157 1.3 thorpej }
158 1.1 christos
159 1.30 rmind static int
160 1.30 rmind ksem_sysfini(bool interface)
161 1.1 christos {
162 1.30 rmind int error;
163 1.1 christos
164 1.30 rmind if (interface) {
165 1.30 rmind error = syscall_disestablish(NULL, ksem_syscalls);
166 1.30 rmind if (error != 0) {
167 1.30 rmind return error;
168 1.30 rmind }
169 1.34 rmind /*
170 1.34 rmind * Make sure that no semaphores are in use. Note: semops
171 1.34 rmind * must be unused at this point.
172 1.34 rmind */
173 1.34 rmind if (nsems_total) {
174 1.30 rmind error = syscall_establish(NULL, ksem_syscalls);
175 1.30 rmind KASSERT(error == 0);
176 1.30 rmind return EBUSY;
177 1.30 rmind }
178 1.3 thorpej }
179 1.30 rmind mutex_destroy(&ksem_lock);
180 1.30 rmind return 0;
181 1.3 thorpej }
182 1.3 thorpej
183 1.30 rmind static int
184 1.30 rmind ksem_modcmd(modcmd_t cmd, void *arg)
185 1.3 thorpej {
186 1.3 thorpej
187 1.30 rmind switch (cmd) {
188 1.30 rmind case MODULE_CMD_INIT:
189 1.30 rmind return ksem_sysinit();
190 1.3 thorpej
191 1.30 rmind case MODULE_CMD_FINI:
192 1.30 rmind return ksem_sysfini(true);
193 1.1 christos
194 1.30 rmind default:
195 1.30 rmind return ENOTTY;
196 1.16 thorpej }
197 1.16 thorpej }
198 1.16 thorpej
199 1.30 rmind static ksem_t *
200 1.30 rmind ksem_lookup(const char *name)
201 1.3 thorpej {
202 1.30 rmind ksem_t *ks;
203 1.3 thorpej
204 1.30 rmind KASSERT(mutex_owned(&ksem_lock));
205 1.3 thorpej
206 1.30 rmind LIST_FOREACH(ks, &ksem_head, ks_entry) {
207 1.30 rmind if (strcmp(ks->ks_name, name) == 0) {
208 1.30 rmind mutex_enter(&ks->ks_lock);
209 1.30 rmind return ks;
210 1.3 thorpej }
211 1.1 christos }
212 1.30 rmind return NULL;
213 1.1 christos }
214 1.1 christos
215 1.3 thorpej static int
216 1.30 rmind ksem_perm(lwp_t *l, ksem_t *ks)
217 1.3 thorpej {
218 1.30 rmind kauth_cred_t uc = l->l_cred;
219 1.30 rmind mode_t mode = ks->ks_mode;
220 1.3 thorpej
221 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
222 1.30 rmind if ((kauth_cred_geteuid(uc) == ks->ks_uid && (mode & S_IWUSR) != 0) ||
223 1.30 rmind (kauth_cred_getegid(uc) == ks->ks_gid && (mode & S_IWGRP) != 0) ||
224 1.30 rmind (mode & S_IWOTH) != 0 ||
225 1.19 elad kauth_authorize_generic(uc, KAUTH_GENERIC_ISSUSER, NULL) == 0)
226 1.30 rmind return 0;
227 1.30 rmind
228 1.30 rmind return EACCES;
229 1.3 thorpej }
230 1.3 thorpej
231 1.30 rmind /*
232 1.30 rmind * ksem_get: get the semaphore from the descriptor.
233 1.30 rmind *
234 1.30 rmind * => locks the semaphore, if found.
235 1.30 rmind * => holds a reference on the file descriptor.
236 1.30 rmind */
237 1.30 rmind static int
238 1.30 rmind ksem_get(int fd, ksem_t **ksret)
239 1.13 cube {
240 1.30 rmind ksem_t *ks;
241 1.30 rmind file_t *fp;
242 1.13 cube
243 1.30 rmind fp = fd_getfile(fd);
244 1.30 rmind if (__predict_false(fp == NULL)) {
245 1.30 rmind return EBADF;
246 1.30 rmind }
247 1.30 rmind if (__predict_false(fp->f_type != DTYPE_SEM)) {
248 1.30 rmind fd_putfile(fd);
249 1.30 rmind return EBADF;
250 1.13 cube }
251 1.30 rmind ks = fp->f_data;
252 1.30 rmind mutex_enter(&ks->ks_lock);
253 1.13 cube
254 1.30 rmind *ksret = ks;
255 1.30 rmind return 0;
256 1.1 christos }
257 1.1 christos
258 1.30 rmind /*
259 1.30 rmind * ksem_create: allocate and setup a new semaphore structure.
260 1.30 rmind */
261 1.1 christos static int
262 1.30 rmind ksem_create(lwp_t *l, const char *name, ksem_t **ksret, mode_t mode, u_int val)
263 1.1 christos {
264 1.30 rmind ksem_t *ks;
265 1.14 elad kauth_cred_t uc;
266 1.30 rmind char *kname;
267 1.1 christos size_t len;
268 1.1 christos
269 1.30 rmind /* Pre-check for the limit. */
270 1.30 rmind if (nsems >= ksem_max) {
271 1.30 rmind return ENFILE;
272 1.30 rmind }
273 1.30 rmind
274 1.30 rmind if (val > SEM_VALUE_MAX) {
275 1.30 rmind return EINVAL;
276 1.30 rmind }
277 1.30 rmind
278 1.1 christos if (name != NULL) {
279 1.1 christos len = strlen(name);
280 1.1 christos if (len > SEM_MAX_NAMELEN) {
281 1.30 rmind return ENAMETOOLONG;
282 1.1 christos }
283 1.30 rmind /* Name must start with a '/' but not contain one. */
284 1.1 christos if (*name != '/' || len < 2 || strchr(name + 1, '/') != NULL) {
285 1.30 rmind return EINVAL;
286 1.1 christos }
287 1.30 rmind kname = kmem_alloc(++len, KM_SLEEP);
288 1.30 rmind strlcpy(kname, name, len);
289 1.30 rmind } else {
290 1.30 rmind kname = NULL;
291 1.30 rmind len = 0;
292 1.30 rmind }
293 1.30 rmind
294 1.30 rmind ks = kmem_zalloc(sizeof(ksem_t), KM_SLEEP);
295 1.30 rmind mutex_init(&ks->ks_lock, MUTEX_DEFAULT, IPL_NONE);
296 1.30 rmind cv_init(&ks->ks_cv, "psem");
297 1.30 rmind ks->ks_name = kname;
298 1.30 rmind ks->ks_namelen = len;
299 1.30 rmind ks->ks_mode = mode;
300 1.30 rmind ks->ks_value = val;
301 1.30 rmind ks->ks_ref = 1;
302 1.30 rmind
303 1.30 rmind uc = l->l_cred;
304 1.30 rmind ks->ks_uid = kauth_cred_geteuid(uc);
305 1.30 rmind ks->ks_gid = kauth_cred_getegid(uc);
306 1.30 rmind
307 1.34 rmind atomic_inc_uint(&nsems_total);
308 1.30 rmind *ksret = ks;
309 1.30 rmind return 0;
310 1.30 rmind }
311 1.30 rmind
312 1.30 rmind static void
313 1.30 rmind ksem_free(ksem_t *ks)
314 1.30 rmind {
315 1.3 thorpej
316 1.34 rmind KASSERT(!cv_has_waiters(&ks->ks_cv));
317 1.34 rmind
318 1.30 rmind if (ks->ks_name) {
319 1.30 rmind KASSERT(ks->ks_namelen > 0);
320 1.30 rmind kmem_free(ks->ks_name, ks->ks_namelen);
321 1.13 cube }
322 1.30 rmind mutex_destroy(&ks->ks_lock);
323 1.30 rmind cv_destroy(&ks->ks_cv);
324 1.30 rmind kmem_free(ks, sizeof(ksem_t));
325 1.34 rmind
326 1.34 rmind atomic_dec_uint(&nsems_total);
327 1.1 christos }
328 1.1 christos
329 1.1 christos int
330 1.30 rmind sys__ksem_init(struct lwp *l, const struct sys__ksem_init_args *uap,
331 1.30 rmind register_t *retval)
332 1.1 christos {
333 1.23 dsl /* {
334 1.1 christos unsigned int value;
335 1.29 ad intptr_t *idp;
336 1.23 dsl } */
337 1.13 cube
338 1.13 cube return do_ksem_init(l, SCARG(uap, value), SCARG(uap, idp), copyout);
339 1.13 cube }
340 1.13 cube
341 1.13 cube int
342 1.30 rmind do_ksem_init(lwp_t *l, u_int val, intptr_t *idp, copyout_t docopyout)
343 1.13 cube {
344 1.30 rmind proc_t *p = l->l_proc;
345 1.30 rmind ksem_t *ks;
346 1.30 rmind file_t *fp;
347 1.29 ad intptr_t id;
348 1.30 rmind int fd, error;
349 1.1 christos
350 1.30 rmind error = fd_allocfile(&fp, &fd);
351 1.1 christos if (error) {
352 1.30 rmind return error;
353 1.1 christos }
354 1.30 rmind fp->f_type = DTYPE_SEM;
355 1.30 rmind fp->f_flag = FREAD | FWRITE;
356 1.30 rmind fp->f_ops = &semops;
357 1.3 thorpej
358 1.30 rmind id = (intptr_t)fd;
359 1.30 rmind error = (*docopyout)(&id, idp, sizeof(*idp));
360 1.30 rmind if (error) {
361 1.30 rmind fd_abort(p, fp, fd);
362 1.30 rmind return error;
363 1.30 rmind }
364 1.3 thorpej
365 1.30 rmind /* Note the mode does not matter for anonymous semaphores. */
366 1.30 rmind error = ksem_create(l, NULL, &ks, 0, val);
367 1.30 rmind if (error) {
368 1.30 rmind fd_abort(p, fp, fd);
369 1.30 rmind return error;
370 1.30 rmind }
371 1.30 rmind fp->f_data = ks;
372 1.30 rmind fd_affix(p, fp, fd);
373 1.30 rmind return error;
374 1.1 christos }
375 1.1 christos
376 1.1 christos int
377 1.30 rmind sys__ksem_open(struct lwp *l, const struct sys__ksem_open_args *uap,
378 1.30 rmind register_t *retval)
379 1.1 christos {
380 1.23 dsl /* {
381 1.1 christos const char *name;
382 1.1 christos int oflag;
383 1.1 christos mode_t mode;
384 1.1 christos unsigned int value;
385 1.29 ad intptr_t *idp;
386 1.23 dsl } */
387 1.13 cube
388 1.13 cube return do_ksem_open(l, SCARG(uap, name), SCARG(uap, oflag),
389 1.13 cube SCARG(uap, mode), SCARG(uap, value), SCARG(uap, idp), copyout);
390 1.13 cube }
391 1.13 cube
392 1.13 cube int
393 1.13 cube do_ksem_open(struct lwp *l, const char *semname, int oflag, mode_t mode,
394 1.29 ad unsigned int value, intptr_t *idp, copyout_t docopyout)
395 1.13 cube {
396 1.1 christos char name[SEM_MAX_NAMELEN + 1];
397 1.30 rmind proc_t *p = l->l_proc;
398 1.30 rmind ksem_t *ksnew = NULL, *ks;
399 1.30 rmind file_t *fp;
400 1.29 ad intptr_t id;
401 1.30 rmind int fd, error;
402 1.1 christos
403 1.30 rmind error = copyinstr(semname, name, sizeof(name), NULL);
404 1.30 rmind if (error) {
405 1.30 rmind return error;
406 1.30 rmind }
407 1.30 rmind error = fd_allocfile(&fp, &fd);
408 1.30 rmind if (error) {
409 1.30 rmind return error;
410 1.30 rmind }
411 1.30 rmind fp->f_type = DTYPE_SEM;
412 1.30 rmind fp->f_flag = FREAD | FWRITE;
413 1.30 rmind fp->f_ops = &semops;
414 1.30 rmind
415 1.30 rmind /*
416 1.30 rmind * The ID (file descriptor number) can be stored early.
417 1.30 rmind * Note that zero is a special value for libpthread.
418 1.30 rmind */
419 1.30 rmind id = (intptr_t)fd;
420 1.30 rmind error = (*docopyout)(&id, idp, sizeof(*idp));
421 1.30 rmind if (error) {
422 1.30 rmind goto err;
423 1.30 rmind }
424 1.30 rmind
425 1.30 rmind if (oflag & O_CREAT) {
426 1.30 rmind /* Create a new semaphore. */
427 1.30 rmind error = ksem_create(l, name, &ksnew, mode, value);
428 1.30 rmind if (error) {
429 1.30 rmind goto err;
430 1.30 rmind }
431 1.30 rmind KASSERT(ksnew != NULL);
432 1.30 rmind }
433 1.1 christos
434 1.30 rmind /* Lookup for a semaphore with such name. */
435 1.30 rmind mutex_enter(&ksem_lock);
436 1.30 rmind ks = ksem_lookup(name);
437 1.30 rmind if (ks) {
438 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
439 1.30 rmind mutex_exit(&ksem_lock);
440 1.3 thorpej
441 1.3 thorpej /* Check for exclusive create. */
442 1.13 cube if (oflag & O_EXCL) {
443 1.30 rmind mutex_exit(&ks->ks_lock);
444 1.30 rmind error = EEXIST;
445 1.30 rmind goto err;
446 1.1 christos }
447 1.1 christos /*
448 1.30 rmind * Verify permissions. If we can access it,
449 1.30 rmind * add the reference of this thread.
450 1.1 christos */
451 1.15 ad error = ksem_perm(l, ks);
452 1.30 rmind if (error == 0) {
453 1.30 rmind ks->ks_ref++;
454 1.30 rmind }
455 1.30 rmind mutex_exit(&ks->ks_lock);
456 1.1 christos if (error) {
457 1.30 rmind goto err;
458 1.30 rmind }
459 1.30 rmind } else {
460 1.30 rmind /* Fail if not found and not creating. */
461 1.30 rmind if ((oflag & O_CREAT) == 0) {
462 1.30 rmind mutex_exit(&ksem_lock);
463 1.30 rmind KASSERT(ksnew == NULL);
464 1.31 rmind error = ENOENT;
465 1.31 rmind goto err;
466 1.1 christos }
467 1.3 thorpej
468 1.30 rmind /* Check for the limit locked. */
469 1.30 rmind if (nsems >= ksem_max) {
470 1.30 rmind mutex_exit(&ksem_lock);
471 1.30 rmind error = ENFILE;
472 1.30 rmind goto err;
473 1.30 rmind }
474 1.3 thorpej
475 1.30 rmind /*
476 1.32 rmind * Finally, insert semaphore into the list.
477 1.30 rmind * Note: it already has the initial reference.
478 1.30 rmind */
479 1.30 rmind ks = ksnew;
480 1.30 rmind LIST_INSERT_HEAD(&ksem_head, ks, ks_entry);
481 1.30 rmind nsems++;
482 1.30 rmind mutex_exit(&ksem_lock);
483 1.30 rmind
484 1.30 rmind ksnew = NULL;
485 1.30 rmind }
486 1.30 rmind KASSERT(ks != NULL);
487 1.30 rmind fp->f_data = ks;
488 1.30 rmind fd_affix(p, fp, fd);
489 1.30 rmind err:
490 1.30 rmind if (error) {
491 1.30 rmind fd_abort(p, fp, fd);
492 1.3 thorpej }
493 1.30 rmind if (ksnew) {
494 1.30 rmind ksem_free(ksnew);
495 1.1 christos }
496 1.30 rmind return error;
497 1.30 rmind }
498 1.1 christos
499 1.30 rmind int
500 1.30 rmind sys__ksem_close(struct lwp *l, const struct sys__ksem_close_args *uap,
501 1.30 rmind register_t *retval)
502 1.30 rmind {
503 1.30 rmind /* {
504 1.30 rmind intptr_t id;
505 1.30 rmind } */
506 1.33 rmind int fd = (int)SCARG(uap, id);
507 1.33 rmind
508 1.33 rmind if (fd_getfile(fd) == NULL) {
509 1.33 rmind return EBADF;
510 1.33 rmind }
511 1.33 rmind return fd_close(fd);
512 1.1 christos }
513 1.1 christos
514 1.30 rmind static int
515 1.30 rmind ksem_close_fop(file_t *fp)
516 1.1 christos {
517 1.30 rmind ksem_t *ks = fp->f_data;
518 1.30 rmind bool destroy = false;
519 1.1 christos
520 1.30 rmind mutex_enter(&ks->ks_lock);
521 1.30 rmind KASSERT(ks->ks_ref > 0);
522 1.30 rmind if (--ks->ks_ref == 0) {
523 1.30 rmind /*
524 1.30 rmind * Destroy if the last reference and semaphore is unnamed,
525 1.30 rmind * or unlinked (for named semaphore).
526 1.30 rmind */
527 1.30 rmind destroy = (ks->ks_flags & KS_UNLINKED) || (ks->ks_name == NULL);
528 1.1 christos }
529 1.30 rmind mutex_exit(&ks->ks_lock);
530 1.3 thorpej
531 1.30 rmind if (destroy) {
532 1.30 rmind ksem_free(ks);
533 1.30 rmind }
534 1.30 rmind return 0;
535 1.1 christos }
536 1.1 christos
537 1.1 christos int
538 1.30 rmind sys__ksem_unlink(struct lwp *l, const struct sys__ksem_unlink_args *uap,
539 1.30 rmind register_t *retval)
540 1.1 christos {
541 1.23 dsl /* {
542 1.1 christos const char *name;
543 1.23 dsl } */
544 1.30 rmind char name[SEM_MAX_NAMELEN + 1];
545 1.30 rmind ksem_t *ks;
546 1.30 rmind u_int refcnt;
547 1.1 christos int error;
548 1.1 christos
549 1.30 rmind error = copyinstr(SCARG(uap, name), name, sizeof(name), NULL);
550 1.1 christos if (error)
551 1.1 christos return error;
552 1.1 christos
553 1.30 rmind mutex_enter(&ksem_lock);
554 1.30 rmind ks = ksem_lookup(name);
555 1.3 thorpej if (ks == NULL) {
556 1.30 rmind mutex_exit(&ksem_lock);
557 1.30 rmind return ENOENT;
558 1.1 christos }
559 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
560 1.3 thorpej
561 1.30 rmind /* Verify permissions. */
562 1.30 rmind error = ksem_perm(l, ks);
563 1.30 rmind if (error) {
564 1.30 rmind mutex_exit(&ks->ks_lock);
565 1.30 rmind mutex_exit(&ksem_lock);
566 1.30 rmind return error;
567 1.30 rmind }
568 1.3 thorpej
569 1.31 rmind /* Remove from the global list. */
570 1.3 thorpej LIST_REMOVE(ks, ks_entry);
571 1.30 rmind nsems--;
572 1.31 rmind mutex_exit(&ksem_lock);
573 1.3 thorpej
574 1.30 rmind refcnt = ks->ks_ref;
575 1.30 rmind if (refcnt) {
576 1.30 rmind /* Mark as unlinked, if there are references. */
577 1.30 rmind ks->ks_flags |= KS_UNLINKED;
578 1.30 rmind }
579 1.30 rmind mutex_exit(&ks->ks_lock);
580 1.3 thorpej
581 1.30 rmind if (refcnt == 0) {
582 1.3 thorpej ksem_free(ks);
583 1.30 rmind }
584 1.30 rmind return 0;
585 1.1 christos }
586 1.1 christos
587 1.1 christos int
588 1.30 rmind sys__ksem_post(struct lwp *l, const struct sys__ksem_post_args *uap,
589 1.30 rmind register_t *retval)
590 1.1 christos {
591 1.23 dsl /* {
592 1.29 ad intptr_t id;
593 1.23 dsl } */
594 1.30 rmind int fd = (int)SCARG(uap, id), error;
595 1.30 rmind ksem_t *ks;
596 1.1 christos
597 1.30 rmind error = ksem_get(fd, &ks);
598 1.30 rmind if (error) {
599 1.30 rmind return error;
600 1.3 thorpej }
601 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
602 1.1 christos if (ks->ks_value == SEM_VALUE_MAX) {
603 1.1 christos error = EOVERFLOW;
604 1.3 thorpej goto out;
605 1.1 christos }
606 1.30 rmind ks->ks_value++;
607 1.30 rmind if (ks->ks_waiters) {
608 1.20 ad cv_broadcast(&ks->ks_cv);
609 1.30 rmind }
610 1.30 rmind out:
611 1.30 rmind mutex_exit(&ks->ks_lock);
612 1.30 rmind fd_putfile(fd);
613 1.30 rmind return error;
614 1.3 thorpej }
615 1.3 thorpej
616 1.36 joerg int
617 1.36 joerg do_ksem_wait(lwp_t *l, intptr_t id, bool try, struct timespec *abstime)
618 1.3 thorpej {
619 1.36 joerg int fd = (int)id, error, timeo;
620 1.30 rmind ksem_t *ks;
621 1.3 thorpej
622 1.30 rmind error = ksem_get(fd, &ks);
623 1.30 rmind if (error) {
624 1.30 rmind return error;
625 1.30 rmind }
626 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
627 1.3 thorpej while (ks->ks_value == 0) {
628 1.3 thorpej ks->ks_waiters++;
629 1.36 joerg if (!try && abstime != NULL) {
630 1.36 joerg error = abstimeout2timo(abstime, &timeo);
631 1.36 joerg if (error != 0)
632 1.36 joerg goto out;
633 1.36 joerg } else {
634 1.36 joerg timeo = 0;
635 1.36 joerg }
636 1.36 joerg error = try ? EAGAIN : cv_timedwait_sig(&ks->ks_cv,
637 1.36 joerg &ks->ks_lock, timeo);
638 1.3 thorpej ks->ks_waiters--;
639 1.3 thorpej if (error)
640 1.3 thorpej goto out;
641 1.3 thorpej }
642 1.3 thorpej ks->ks_value--;
643 1.30 rmind out:
644 1.30 rmind mutex_exit(&ks->ks_lock);
645 1.30 rmind fd_putfile(fd);
646 1.30 rmind return error;
647 1.1 christos }
648 1.1 christos
649 1.1 christos int
650 1.30 rmind sys__ksem_wait(struct lwp *l, const struct sys__ksem_wait_args *uap,
651 1.30 rmind register_t *retval)
652 1.1 christos {
653 1.23 dsl /* {
654 1.29 ad intptr_t id;
655 1.23 dsl } */
656 1.1 christos
657 1.36 joerg return do_ksem_wait(l, SCARG(uap, id), false, NULL);
658 1.36 joerg }
659 1.36 joerg
660 1.36 joerg int
661 1.36 joerg sys__ksem_timedwait(struct lwp *l, const struct sys__ksem_timedwait_args *uap,
662 1.36 joerg register_t *retval)
663 1.36 joerg {
664 1.36 joerg /* {
665 1.36 joerg intptr_t id;
666 1.36 joerg const struct timespec *abstime;
667 1.36 joerg } */
668 1.36 joerg struct timespec ts;
669 1.36 joerg int error;
670 1.36 joerg
671 1.36 joerg error = copyin(SCARG(uap, abstime), &ts, sizeof(ts));
672 1.36 joerg if (error != 0)
673 1.36 joerg return error;
674 1.36 joerg
675 1.36 joerg if (ts.tv_sec < 0 || ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000)
676 1.36 joerg return EINVAL;
677 1.36 joerg
678 1.36 joerg error = do_ksem_wait(l, SCARG(uap, id), false, &ts);
679 1.36 joerg if (error == EWOULDBLOCK)
680 1.36 joerg error = ETIMEDOUT;
681 1.36 joerg return error;
682 1.1 christos }
683 1.1 christos
684 1.1 christos int
685 1.30 rmind sys__ksem_trywait(struct lwp *l, const struct sys__ksem_trywait_args *uap,
686 1.30 rmind register_t *retval)
687 1.1 christos {
688 1.23 dsl /* {
689 1.29 ad intptr_t id;
690 1.23 dsl } */
691 1.1 christos
692 1.36 joerg return do_ksem_wait(l, SCARG(uap, id), true, NULL);
693 1.1 christos }
694 1.1 christos
695 1.1 christos int
696 1.30 rmind sys__ksem_getvalue(struct lwp *l, const struct sys__ksem_getvalue_args *uap,
697 1.30 rmind register_t *retval)
698 1.1 christos {
699 1.23 dsl /* {
700 1.29 ad intptr_t id;
701 1.1 christos unsigned int *value;
702 1.23 dsl } */
703 1.30 rmind int fd = (int)SCARG(uap, id), error;
704 1.30 rmind ksem_t *ks;
705 1.1 christos unsigned int val;
706 1.1 christos
707 1.30 rmind error = ksem_get(fd, &ks);
708 1.30 rmind if (error) {
709 1.30 rmind return error;
710 1.30 rmind }
711 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
712 1.1 christos val = ks->ks_value;
713 1.30 rmind mutex_exit(&ks->ks_lock);
714 1.30 rmind fd_putfile(fd);
715 1.3 thorpej
716 1.30 rmind return copyout(&val, SCARG(uap, value), sizeof(val));
717 1.1 christos }
718 1.1 christos
719 1.1 christos int
720 1.30 rmind sys__ksem_destroy(struct lwp *l, const struct sys__ksem_destroy_args *uap,
721 1.30 rmind register_t *retval)
722 1.1 christos {
723 1.23 dsl /* {
724 1.29 ad intptr_t id;
725 1.23 dsl } */
726 1.30 rmind int fd = (int)SCARG(uap, id), error;
727 1.30 rmind ksem_t *ks;
728 1.1 christos
729 1.30 rmind error = ksem_get(fd, &ks);
730 1.30 rmind if (error) {
731 1.30 rmind return error;
732 1.3 thorpej }
733 1.30 rmind KASSERT(mutex_owned(&ks->ks_lock));
734 1.3 thorpej
735 1.30 rmind /* Operation is only for unnamed semaphores. */
736 1.3 thorpej if (ks->ks_name != NULL) {
737 1.30 rmind error = EINVAL;
738 1.30 rmind goto out;
739 1.3 thorpej }
740 1.30 rmind /* Cannot destroy if there are waiters. */
741 1.3 thorpej if (ks->ks_waiters) {
742 1.30 rmind error = EBUSY;
743 1.30 rmind goto out;
744 1.3 thorpej }
745 1.30 rmind out:
746 1.30 rmind mutex_exit(&ks->ks_lock);
747 1.30 rmind if (error) {
748 1.32 rmind fd_putfile(fd);
749 1.27 ad return error;
750 1.27 ad }
751 1.32 rmind return fd_close(fd);
752 1.22 rmind }
753