uipc_sem.c revision 1.15 1 1.15 ad /* $NetBSD: uipc_sem.c,v 1.15 2006/07/23 22:06:11 ad Exp $ */
2 1.3 thorpej
3 1.3 thorpej /*-
4 1.3 thorpej * Copyright (c) 2003 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 1.3 thorpej * by Jason R. Thorpe of Wasabi Systems, Inc.
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 * 3. All advertising materials mentioning features or use of this software
19 1.3 thorpej * must display the following acknowledgement:
20 1.3 thorpej * This product includes software developed by the NetBSD
21 1.3 thorpej * Foundation, Inc. and its contributors.
22 1.3 thorpej * 4. Neither the name of The NetBSD Foundation nor the names of its
23 1.3 thorpej * contributors may be used to endorse or promote products derived
24 1.3 thorpej * from this software without specific prior written permission.
25 1.3 thorpej *
26 1.3 thorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 1.3 thorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 1.3 thorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 1.3 thorpej * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 1.3 thorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 1.3 thorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 1.3 thorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 1.3 thorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 1.3 thorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 1.3 thorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 1.3 thorpej * POSSIBILITY OF SUCH DAMAGE.
37 1.3 thorpej */
38 1.1 christos
39 1.1 christos /*
40 1.1 christos * Copyright (c) 2002 Alfred Perlstein <alfred (at) FreeBSD.org>
41 1.1 christos * All rights reserved.
42 1.1 christos *
43 1.1 christos * Redistribution and use in source and binary forms, with or without
44 1.1 christos * modification, are permitted provided that the following conditions
45 1.1 christos * are met:
46 1.1 christos * 1. Redistributions of source code must retain the above copyright
47 1.1 christos * notice, this list of conditions and the following disclaimer.
48 1.1 christos * 2. Redistributions in binary form must reproduce the above copyright
49 1.1 christos * notice, this list of conditions and the following disclaimer in the
50 1.1 christos * documentation and/or other materials provided with the distribution.
51 1.1 christos *
52 1.1 christos * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
53 1.1 christos * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 1.1 christos * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 1.1 christos * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
56 1.1 christos * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 1.1 christos * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 1.1 christos * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 1.1 christos * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 1.1 christos * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 1.1 christos * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62 1.1 christos * SUCH DAMAGE.
63 1.1 christos */
64 1.9 lukem
65 1.9 lukem #include <sys/cdefs.h>
66 1.15 ad __KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.15 2006/07/23 22:06:11 ad Exp $");
67 1.1 christos
68 1.1 christos #include "opt_posix.h"
69 1.1 christos
70 1.1 christos #include <sys/param.h>
71 1.1 christos #include <sys/systm.h>
72 1.1 christos #include <sys/kernel.h>
73 1.1 christos #include <sys/proc.h>
74 1.1 christos #include <sys/lock.h>
75 1.1 christos #include <sys/ksem.h>
76 1.5 matt #include <sys/sa.h>
77 1.1 christos #include <sys/syscall.h>
78 1.1 christos #include <sys/stat.h>
79 1.1 christos #include <sys/malloc.h>
80 1.1 christos #include <sys/fcntl.h>
81 1.14 elad #include <sys/kauth.h>
82 1.1 christos
83 1.1 christos #include <sys/mount.h>
84 1.1 christos
85 1.1 christos #include <sys/syscallargs.h>
86 1.1 christos
87 1.1 christos #ifndef SEM_MAX
88 1.1 christos #define SEM_MAX 30
89 1.1 christos #endif
90 1.1 christos
91 1.1 christos #define SEM_MAX_NAMELEN 14
92 1.1 christos #define SEM_VALUE_MAX (~0U)
93 1.13 cube #define SEM_HASHTBL_SIZE 13
94 1.1 christos
95 1.13 cube #define SEM_TO_ID(x) (((x)->ks_id))
96 1.13 cube #define SEM_HASH(id) ((id) % SEM_HASHTBL_SIZE)
97 1.4 thorpej
98 1.4 thorpej MALLOC_DEFINE(M_SEM, "p1003_1b_sem", "p1003_1b semaphores");
99 1.1 christos
100 1.3 thorpej /*
101 1.3 thorpej * Note: to read the ks_name member, you need either the ks_interlock
102 1.3 thorpej * or the ksem_slock. To write the ks_name member, you need both. Make
103 1.3 thorpej * sure the order is ksem_slock -> ks_interlock.
104 1.3 thorpej */
105 1.1 christos struct ksem {
106 1.1 christos LIST_ENTRY(ksem) ks_entry; /* global list entry */
107 1.13 cube LIST_ENTRY(ksem) ks_hash; /* hash list entry */
108 1.3 thorpej struct simplelock ks_interlock; /* lock on this ksem */
109 1.1 christos char *ks_name; /* if named, this is the name */
110 1.3 thorpej unsigned int ks_ref; /* number of references */
111 1.1 christos mode_t ks_mode; /* protection bits */
112 1.1 christos uid_t ks_uid; /* creator uid */
113 1.1 christos gid_t ks_gid; /* creator gid */
114 1.1 christos unsigned int ks_value; /* current value */
115 1.3 thorpej unsigned int ks_waiters; /* number of waiters */
116 1.13 cube semid_t ks_id; /* unique identifier */
117 1.3 thorpej };
118 1.3 thorpej
119 1.3 thorpej struct ksem_ref {
120 1.3 thorpej LIST_ENTRY(ksem_ref) ksr_list;
121 1.3 thorpej struct ksem *ksr_ksem;
122 1.3 thorpej };
123 1.3 thorpej
124 1.3 thorpej struct ksem_proc {
125 1.3 thorpej struct lock kp_lock;
126 1.3 thorpej LIST_HEAD(, ksem_ref) kp_ksems;
127 1.1 christos };
128 1.1 christos
129 1.13 cube LIST_HEAD(ksem_list, ksem);
130 1.13 cube
131 1.1 christos /*
132 1.3 thorpej * ksem_slock protects ksem_head and nsems. Only named semaphores go
133 1.3 thorpej * onto ksem_head.
134 1.1 christos */
135 1.1 christos static struct simplelock ksem_slock;
136 1.13 cube static struct ksem_list ksem_head = LIST_HEAD_INITIALIZER(&ksem_head);
137 1.13 cube static struct ksem_list ksem_hash[SEM_HASHTBL_SIZE];
138 1.3 thorpej static int nsems = 0;
139 1.1 christos
140 1.13 cube /*
141 1.13 cube * ksem_counter is the last assigned semid_t. It needs to be COMPAT_NETBSD32
142 1.13 cube * friendly, even though semid_t itself is defined as uintptr_t.
143 1.13 cube */
144 1.13 cube static uint32_t ksem_counter = 1;
145 1.13 cube
146 1.13 cube
147 1.3 thorpej static void
148 1.3 thorpej ksem_free(struct ksem *ks)
149 1.3 thorpej {
150 1.1 christos
151 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
152 1.3 thorpej /*
153 1.3 thorpej * If the ksem is anonymous (or has been unlinked), then
154 1.3 thorpej * this is the end if its life.
155 1.3 thorpej */
156 1.3 thorpej if (ks->ks_name == NULL) {
157 1.3 thorpej simple_unlock(&ks->ks_interlock);
158 1.1 christos
159 1.3 thorpej simple_lock(&ksem_slock);
160 1.3 thorpej nsems--;
161 1.13 cube LIST_REMOVE(ks, ks_hash);
162 1.3 thorpej simple_unlock(&ksem_slock);
163 1.13 cube
164 1.13 cube free(ks, M_SEM);
165 1.3 thorpej return;
166 1.3 thorpej }
167 1.3 thorpej simple_unlock(&ks->ks_interlock);
168 1.3 thorpej }
169 1.1 christos
170 1.12 perry static inline void
171 1.3 thorpej ksem_addref(struct ksem *ks)
172 1.1 christos {
173 1.1 christos
174 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
175 1.1 christos ks->ks_ref++;
176 1.3 thorpej KASSERT(ks->ks_ref != 0); /* XXX KDASSERT */
177 1.1 christos }
178 1.1 christos
179 1.12 perry static inline void
180 1.3 thorpej ksem_delref(struct ksem *ks)
181 1.1 christos {
182 1.1 christos
183 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
184 1.3 thorpej KASSERT(ks->ks_ref != 0); /* XXX KDASSERT */
185 1.3 thorpej if (--ks->ks_ref == 0) {
186 1.1 christos ksem_free(ks);
187 1.3 thorpej return;
188 1.3 thorpej }
189 1.3 thorpej simple_unlock(&ks->ks_interlock);
190 1.3 thorpej }
191 1.3 thorpej
192 1.3 thorpej static struct ksem_proc *
193 1.3 thorpej ksem_proc_alloc(void)
194 1.3 thorpej {
195 1.3 thorpej struct ksem_proc *kp;
196 1.3 thorpej
197 1.3 thorpej kp = malloc(sizeof(*kp), M_SEM, M_WAITOK);
198 1.3 thorpej lockinit(&kp->kp_lock, PWAIT, "ksproc", 0, 0);
199 1.3 thorpej LIST_INIT(&kp->kp_ksems);
200 1.3 thorpej
201 1.3 thorpej return (kp);
202 1.1 christos }
203 1.1 christos
204 1.3 thorpej static void
205 1.3 thorpej ksem_add_proc(struct proc *p, struct ksem *ks)
206 1.3 thorpej {
207 1.3 thorpej struct ksem_proc *kp;
208 1.3 thorpej struct ksem_ref *ksr;
209 1.3 thorpej
210 1.3 thorpej if (p->p_ksems == NULL) {
211 1.3 thorpej kp = ksem_proc_alloc();
212 1.3 thorpej p->p_ksems = kp;
213 1.3 thorpej } else
214 1.3 thorpej kp = p->p_ksems;
215 1.3 thorpej
216 1.3 thorpej ksr = malloc(sizeof(*ksr), M_SEM, M_WAITOK);
217 1.3 thorpej ksr->ksr_ksem = ks;
218 1.3 thorpej
219 1.3 thorpej lockmgr(&kp->kp_lock, LK_EXCLUSIVE, NULL);
220 1.3 thorpej LIST_INSERT_HEAD(&kp->kp_ksems, ksr, ksr_list);
221 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
222 1.3 thorpej }
223 1.3 thorpej
224 1.3 thorpej /* We MUST have a write lock on the ksem_proc list! */
225 1.3 thorpej static struct ksem_ref *
226 1.3 thorpej ksem_drop_proc(struct ksem_proc *kp, struct ksem *ks)
227 1.1 christos {
228 1.3 thorpej struct ksem_ref *ksr;
229 1.1 christos
230 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
231 1.3 thorpej LIST_FOREACH(ksr, &kp->kp_ksems, ksr_list) {
232 1.3 thorpej if (ksr->ksr_ksem == ks) {
233 1.3 thorpej ksem_delref(ks);
234 1.3 thorpej LIST_REMOVE(ksr, ksr_list);
235 1.3 thorpej return (ksr);
236 1.3 thorpej }
237 1.1 christos }
238 1.3 thorpej #ifdef DIAGNOSTIC
239 1.3 thorpej panic("ksem_drop_proc: ksem_proc %p ksem %p", kp, ks);
240 1.3 thorpej #endif
241 1.1 christos return (NULL);
242 1.1 christos }
243 1.1 christos
244 1.3 thorpej static int
245 1.15 ad ksem_perm(struct lwp *l, struct ksem *ks)
246 1.3 thorpej {
247 1.14 elad kauth_cred_t uc;
248 1.3 thorpej
249 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
250 1.15 ad uc = l->l_cred;
251 1.14 elad if ((kauth_cred_geteuid(uc) == ks->ks_uid && (ks->ks_mode & S_IWUSR) != 0) ||
252 1.14 elad (kauth_cred_getegid(uc) == ks->ks_gid && (ks->ks_mode & S_IWGRP) != 0) ||
253 1.14 elad (ks->ks_mode & S_IWOTH) != 0 ||
254 1.15 ad kauth_authorize_generic(uc, KAUTH_GENERIC_ISSUSER, &l->l_acflag) == 0)
255 1.3 thorpej return (0);
256 1.3 thorpej return (EPERM);
257 1.3 thorpej }
258 1.3 thorpej
259 1.1 christos static struct ksem *
260 1.13 cube ksem_lookup_byid(semid_t id)
261 1.13 cube {
262 1.13 cube struct ksem *ks;
263 1.13 cube
264 1.13 cube LOCK_ASSERT(simple_lock_held(&ksem_slock));
265 1.13 cube LIST_FOREACH(ks, &ksem_hash[SEM_HASH(id)], ks_hash) {
266 1.13 cube if (ks->ks_id == id)
267 1.13 cube return ks;
268 1.13 cube }
269 1.13 cube return NULL;
270 1.13 cube }
271 1.13 cube
272 1.13 cube static struct ksem *
273 1.3 thorpej ksem_lookup_byname(const char *name)
274 1.1 christos {
275 1.1 christos struct ksem *ks;
276 1.1 christos
277 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ksem_slock));
278 1.3 thorpej LIST_FOREACH(ks, &ksem_head, ks_entry) {
279 1.3 thorpej if (strcmp(ks->ks_name, name) == 0) {
280 1.3 thorpej simple_lock(&ks->ks_interlock);
281 1.1 christos return (ks);
282 1.3 thorpej }
283 1.3 thorpej }
284 1.1 christos return (NULL);
285 1.1 christos }
286 1.1 christos
287 1.1 christos static int
288 1.15 ad ksem_create(struct lwp *l, const char *name, struct ksem **ksret,
289 1.3 thorpej mode_t mode, unsigned int value)
290 1.1 christos {
291 1.1 christos struct ksem *ret;
292 1.14 elad kauth_cred_t uc;
293 1.1 christos size_t len;
294 1.1 christos
295 1.15 ad uc = l->l_cred;
296 1.1 christos if (value > SEM_VALUE_MAX)
297 1.1 christos return (EINVAL);
298 1.1 christos ret = malloc(sizeof(*ret), M_SEM, M_WAITOK | M_ZERO);
299 1.1 christos if (name != NULL) {
300 1.1 christos len = strlen(name);
301 1.1 christos if (len > SEM_MAX_NAMELEN) {
302 1.1 christos free(ret, M_SEM);
303 1.1 christos return (ENAMETOOLONG);
304 1.1 christos }
305 1.1 christos /* name must start with a '/' but not contain one. */
306 1.1 christos if (*name != '/' || len < 2 || strchr(name + 1, '/') != NULL) {
307 1.1 christos free(ret, M_SEM);
308 1.1 christos return (EINVAL);
309 1.1 christos }
310 1.1 christos ret->ks_name = malloc(len + 1, M_SEM, M_WAITOK);
311 1.6 itojun strlcpy(ret->ks_name, name, len + 1);
312 1.3 thorpej } else
313 1.1 christos ret->ks_name = NULL;
314 1.1 christos ret->ks_mode = mode;
315 1.1 christos ret->ks_value = value;
316 1.1 christos ret->ks_ref = 1;
317 1.1 christos ret->ks_waiters = 0;
318 1.14 elad ret->ks_uid = kauth_cred_geteuid(uc);
319 1.14 elad ret->ks_gid = kauth_cred_getegid(uc);
320 1.3 thorpej simple_lock_init(&ret->ks_interlock);
321 1.3 thorpej
322 1.1 christos simple_lock(&ksem_slock);
323 1.1 christos if (nsems >= SEM_MAX) {
324 1.3 thorpej simple_unlock(&ksem_slock);
325 1.3 thorpej if (ret->ks_name != NULL)
326 1.3 thorpej free(ret->ks_name, M_SEM);
327 1.3 thorpej free(ret, M_SEM);
328 1.3 thorpej return (ENFILE);
329 1.1 christos }
330 1.3 thorpej nsems++;
331 1.13 cube while (ksem_lookup_byid(ksem_counter) != NULL) {
332 1.13 cube ksem_counter++;
333 1.13 cube /* 0 is a special value for libpthread */
334 1.13 cube if (ksem_counter == 0)
335 1.13 cube ksem_counter++;
336 1.13 cube }
337 1.13 cube ret->ks_id = ksem_counter;
338 1.13 cube LIST_INSERT_HEAD(&ksem_hash[SEM_HASH(ret->ks_id)], ret, ks_hash);
339 1.1 christos simple_unlock(&ksem_slock);
340 1.3 thorpej
341 1.3 thorpej *ksret = ret;
342 1.3 thorpej return (0);
343 1.1 christos }
344 1.1 christos
345 1.1 christos int
346 1.2 christos sys__ksem_init(struct lwp *l, void *v, register_t *retval)
347 1.1 christos {
348 1.2 christos struct sys__ksem_init_args /* {
349 1.1 christos unsigned int value;
350 1.1 christos semid_t *idp;
351 1.1 christos } */ *uap = v;
352 1.13 cube
353 1.13 cube return do_ksem_init(l, SCARG(uap, value), SCARG(uap, idp), copyout);
354 1.13 cube }
355 1.13 cube
356 1.13 cube int
357 1.13 cube do_ksem_init(struct lwp *l, unsigned int value, semid_t *idp,
358 1.13 cube copyout_t docopyout)
359 1.13 cube {
360 1.1 christos struct ksem *ks;
361 1.1 christos semid_t id;
362 1.1 christos int error;
363 1.1 christos
364 1.3 thorpej /* Note the mode does not matter for anonymous semaphores. */
365 1.15 ad error = ksem_create(l, NULL, &ks, 0, value);
366 1.1 christos if (error)
367 1.1 christos return (error);
368 1.1 christos id = SEM_TO_ID(ks);
369 1.13 cube error = (*docopyout)(&id, idp, sizeof(id));
370 1.1 christos if (error) {
371 1.3 thorpej simple_lock(&ks->ks_interlock);
372 1.3 thorpej ksem_delref(ks);
373 1.1 christos return (error);
374 1.1 christos }
375 1.3 thorpej
376 1.3 thorpej ksem_add_proc(l->l_proc, ks);
377 1.3 thorpej
378 1.3 thorpej return (0);
379 1.1 christos }
380 1.1 christos
381 1.1 christos int
382 1.2 christos sys__ksem_open(struct lwp *l, void *v, register_t *retval)
383 1.1 christos {
384 1.2 christos struct sys__ksem_open_args /* {
385 1.1 christos const char *name;
386 1.1 christos int oflag;
387 1.1 christos mode_t mode;
388 1.1 christos unsigned int value;
389 1.10 perry semid_t *idp;
390 1.1 christos } */ *uap = v;
391 1.13 cube
392 1.13 cube return do_ksem_open(l, SCARG(uap, name), SCARG(uap, oflag),
393 1.13 cube SCARG(uap, mode), SCARG(uap, value), SCARG(uap, idp), copyout);
394 1.13 cube }
395 1.13 cube
396 1.13 cube int
397 1.13 cube do_ksem_open(struct lwp *l, const char *semname, int oflag, mode_t mode,
398 1.13 cube unsigned int value, semid_t *idp, copyout_t docopyout)
399 1.13 cube {
400 1.1 christos char name[SEM_MAX_NAMELEN + 1];
401 1.1 christos size_t done;
402 1.1 christos int error;
403 1.1 christos struct ksem *ksnew, *ks;
404 1.1 christos semid_t id;
405 1.1 christos
406 1.13 cube error = copyinstr(semname, name, sizeof(name), &done);
407 1.1 christos if (error)
408 1.1 christos return (error);
409 1.1 christos
410 1.1 christos ksnew = NULL;
411 1.1 christos simple_lock(&ksem_slock);
412 1.1 christos ks = ksem_lookup_byname(name);
413 1.3 thorpej
414 1.3 thorpej /* Found one? */
415 1.3 thorpej if (ks != NULL) {
416 1.3 thorpej /* Check for exclusive create. */
417 1.13 cube if (oflag & O_EXCL) {
418 1.3 thorpej simple_unlock(&ks->ks_interlock);
419 1.1 christos simple_unlock(&ksem_slock);
420 1.3 thorpej return (EEXIST);
421 1.1 christos }
422 1.3 thorpej found_one:
423 1.1 christos /*
424 1.3 thorpej * Verify permissions. If we can access it, add
425 1.3 thorpej * this process's reference.
426 1.1 christos */
427 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
428 1.15 ad error = ksem_perm(l, ks);
429 1.3 thorpej if (error == 0)
430 1.3 thorpej ksem_addref(ks);
431 1.3 thorpej simple_unlock(&ks->ks_interlock);
432 1.1 christos simple_unlock(&ksem_slock);
433 1.1 christos if (error)
434 1.1 christos return (error);
435 1.3 thorpej
436 1.1 christos id = SEM_TO_ID(ks);
437 1.13 cube error = (*docopyout)(&id, idp, sizeof(id));
438 1.1 christos if (error) {
439 1.3 thorpej simple_lock(&ks->ks_interlock);
440 1.3 thorpej ksem_delref(ks);
441 1.1 christos return (error);
442 1.1 christos }
443 1.3 thorpej
444 1.3 thorpej ksem_add_proc(l->l_proc, ks);
445 1.3 thorpej
446 1.3 thorpej return (0);
447 1.3 thorpej }
448 1.3 thorpej
449 1.3 thorpej /*
450 1.3 thorpej * didn't ask for creation? error.
451 1.3 thorpej */
452 1.13 cube if ((oflag & O_CREAT) == 0) {
453 1.1 christos simple_unlock(&ksem_slock);
454 1.3 thorpej return (ENOENT);
455 1.1 christos }
456 1.1 christos
457 1.3 thorpej /*
458 1.3 thorpej * We may block during creation, so drop the lock.
459 1.3 thorpej */
460 1.3 thorpej simple_unlock(&ksem_slock);
461 1.15 ad error = ksem_create(l, name, &ksnew, mode, value);
462 1.3 thorpej if (error != 0)
463 1.3 thorpej return (error);
464 1.3 thorpej
465 1.3 thorpej id = SEM_TO_ID(ksnew);
466 1.13 cube error = (*docopyout)(&id, idp, sizeof(id));
467 1.3 thorpej if (error) {
468 1.3 thorpej free(ksnew->ks_name, M_SEM);
469 1.3 thorpej ksnew->ks_name = NULL;
470 1.1 christos
471 1.3 thorpej simple_lock(&ksnew->ks_interlock);
472 1.3 thorpej ksem_delref(ksnew);
473 1.3 thorpej return (error);
474 1.3 thorpej }
475 1.1 christos
476 1.3 thorpej /*
477 1.3 thorpej * We need to make sure we haven't lost a race while
478 1.3 thorpej * allocating during creation.
479 1.3 thorpej */
480 1.3 thorpej simple_lock(&ksem_slock);
481 1.3 thorpej if ((ks = ksem_lookup_byname(name)) != NULL) {
482 1.13 cube if (oflag & O_EXCL) {
483 1.3 thorpej simple_unlock(&ks->ks_interlock);
484 1.3 thorpej simple_unlock(&ksem_slock);
485 1.1 christos
486 1.3 thorpej free(ksnew->ks_name, M_SEM);
487 1.3 thorpej ksnew->ks_name = NULL;
488 1.1 christos
489 1.3 thorpej simple_lock(&ksnew->ks_interlock);
490 1.3 thorpej ksem_delref(ksnew);
491 1.3 thorpej return (EEXIST);
492 1.3 thorpej }
493 1.3 thorpej goto found_one;
494 1.3 thorpej } else {
495 1.3 thorpej /* ksnew already has its initial reference. */
496 1.10 perry LIST_INSERT_HEAD(&ksem_head, ksnew, ks_entry);
497 1.3 thorpej simple_unlock(&ksem_slock);
498 1.1 christos
499 1.3 thorpej ksem_add_proc(l->l_proc, ksnew);
500 1.1 christos }
501 1.3 thorpej return (error);
502 1.1 christos }
503 1.1 christos
504 1.3 thorpej /* We must have a read lock on the ksem_proc list! */
505 1.3 thorpej static struct ksem *
506 1.3 thorpej ksem_lookup_proc(struct ksem_proc *kp, semid_t id)
507 1.1 christos {
508 1.3 thorpej struct ksem_ref *ksr;
509 1.1 christos
510 1.3 thorpej LIST_FOREACH(ksr, &kp->kp_ksems, ksr_list) {
511 1.13 cube if (id == SEM_TO_ID(ksr->ksr_ksem)) {
512 1.3 thorpej simple_lock(&ksr->ksr_ksem->ks_interlock);
513 1.3 thorpej return (ksr->ksr_ksem);
514 1.3 thorpej }
515 1.1 christos }
516 1.3 thorpej
517 1.3 thorpej return (NULL);
518 1.1 christos }
519 1.1 christos
520 1.1 christos int
521 1.2 christos sys__ksem_unlink(struct lwp *l, void *v, register_t *retval)
522 1.1 christos {
523 1.2 christos struct sys__ksem_unlink_args /* {
524 1.1 christos const char *name;
525 1.1 christos } */ *uap = v;
526 1.3 thorpej char name[SEM_MAX_NAMELEN + 1], *cp;
527 1.1 christos size_t done;
528 1.1 christos struct ksem *ks;
529 1.1 christos int error;
530 1.1 christos
531 1.1 christos error = copyinstr(SCARG(uap, name), name, sizeof(name), &done);
532 1.1 christos if (error)
533 1.1 christos return error;
534 1.1 christos
535 1.1 christos simple_lock(&ksem_slock);
536 1.1 christos ks = ksem_lookup_byname(name);
537 1.3 thorpej if (ks == NULL) {
538 1.3 thorpej simple_unlock(&ksem_slock);
539 1.3 thorpej return (ENOENT);
540 1.1 christos }
541 1.3 thorpej
542 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
543 1.3 thorpej
544 1.3 thorpej LIST_REMOVE(ks, ks_entry);
545 1.3 thorpej cp = ks->ks_name;
546 1.3 thorpej ks->ks_name = NULL;
547 1.3 thorpej
548 1.1 christos simple_unlock(&ksem_slock);
549 1.3 thorpej
550 1.3 thorpej if (ks->ks_ref == 0)
551 1.3 thorpej ksem_free(ks);
552 1.3 thorpej else
553 1.3 thorpej simple_unlock(&ks->ks_interlock);
554 1.3 thorpej
555 1.3 thorpej free(cp, M_SEM);
556 1.3 thorpej
557 1.3 thorpej return (0);
558 1.1 christos }
559 1.1 christos
560 1.1 christos int
561 1.2 christos sys__ksem_close(struct lwp *l, void *v, register_t *retval)
562 1.1 christos {
563 1.2 christos struct sys__ksem_close_args /* {
564 1.1 christos semid_t id;
565 1.1 christos } */ *uap = v;
566 1.3 thorpej struct ksem_proc *kp;
567 1.3 thorpej struct ksem_ref *ksr;
568 1.1 christos struct ksem *ks;
569 1.1 christos
570 1.3 thorpej if ((kp = l->l_proc->p_ksems) == NULL)
571 1.3 thorpej return (EINVAL);
572 1.3 thorpej
573 1.3 thorpej lockmgr(&kp->kp_lock, LK_EXCLUSIVE, NULL);
574 1.3 thorpej
575 1.3 thorpej ks = ksem_lookup_proc(kp, SCARG(uap, id));
576 1.3 thorpej if (ks == NULL) {
577 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
578 1.3 thorpej return (EINVAL);
579 1.3 thorpej }
580 1.3 thorpej
581 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
582 1.3 thorpej if (ks->ks_name == NULL) {
583 1.3 thorpej simple_unlock(&ks->ks_interlock);
584 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
585 1.3 thorpej return (EINVAL);
586 1.3 thorpej }
587 1.3 thorpej
588 1.3 thorpej ksr = ksem_drop_proc(kp, ks);
589 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
590 1.3 thorpej free(ksr, M_SEM);
591 1.3 thorpej
592 1.3 thorpej return (0);
593 1.1 christos }
594 1.1 christos
595 1.1 christos int
596 1.2 christos sys__ksem_post(struct lwp *l, void *v, register_t *retval)
597 1.1 christos {
598 1.2 christos struct sys__ksem_post_args /* {
599 1.1 christos semid_t id;
600 1.1 christos } */ *uap = v;
601 1.3 thorpej struct ksem_proc *kp;
602 1.1 christos struct ksem *ks;
603 1.1 christos int error;
604 1.1 christos
605 1.3 thorpej if ((kp = l->l_proc->p_ksems) == NULL)
606 1.3 thorpej return (EINVAL);
607 1.3 thorpej
608 1.3 thorpej lockmgr(&kp->kp_lock, LK_SHARED, NULL);
609 1.3 thorpej ks = ksem_lookup_proc(kp, SCARG(uap, id));
610 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
611 1.3 thorpej if (ks == NULL)
612 1.3 thorpej return (EINVAL);
613 1.3 thorpej
614 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
615 1.1 christos if (ks->ks_value == SEM_VALUE_MAX) {
616 1.1 christos error = EOVERFLOW;
617 1.3 thorpej goto out;
618 1.1 christos }
619 1.1 christos ++ks->ks_value;
620 1.3 thorpej if (ks->ks_waiters)
621 1.1 christos wakeup(ks);
622 1.1 christos error = 0;
623 1.3 thorpej out:
624 1.3 thorpej simple_unlock(&ks->ks_interlock);
625 1.3 thorpej return (error);
626 1.3 thorpej }
627 1.3 thorpej
628 1.3 thorpej static int
629 1.3 thorpej ksem_wait(struct lwp *l, semid_t id, int tryflag)
630 1.3 thorpej {
631 1.3 thorpej struct ksem_proc *kp;
632 1.3 thorpej struct ksem *ks;
633 1.3 thorpej int error;
634 1.3 thorpej
635 1.3 thorpej if ((kp = l->l_proc->p_ksems) == NULL)
636 1.3 thorpej return (EINVAL);
637 1.3 thorpej
638 1.3 thorpej lockmgr(&kp->kp_lock, LK_SHARED, NULL);
639 1.3 thorpej ks = ksem_lookup_proc(kp, id);
640 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
641 1.3 thorpej if (ks == NULL)
642 1.3 thorpej return (EINVAL);
643 1.3 thorpej
644 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
645 1.3 thorpej ksem_addref(ks);
646 1.3 thorpej while (ks->ks_value == 0) {
647 1.3 thorpej ks->ks_waiters++;
648 1.10 perry error = tryflag ? EAGAIN : ltsleep(ks, PCATCH, "psem", 0,
649 1.3 thorpej &ks->ks_interlock);
650 1.3 thorpej ks->ks_waiters--;
651 1.3 thorpej if (error)
652 1.3 thorpej goto out;
653 1.3 thorpej }
654 1.3 thorpej ks->ks_value--;
655 1.3 thorpej error = 0;
656 1.3 thorpej out:
657 1.3 thorpej ksem_delref(ks);
658 1.1 christos return (error);
659 1.1 christos }
660 1.1 christos
661 1.1 christos int
662 1.2 christos sys__ksem_wait(struct lwp *l, void *v, register_t *retval)
663 1.1 christos {
664 1.2 christos struct sys__ksem_wait_args /* {
665 1.1 christos semid_t id;
666 1.1 christos } */ *uap = v;
667 1.1 christos
668 1.1 christos return ksem_wait(l, SCARG(uap, id), 0);
669 1.1 christos }
670 1.1 christos
671 1.1 christos int
672 1.2 christos sys__ksem_trywait(struct lwp *l, void *v, register_t *retval)
673 1.1 christos {
674 1.2 christos struct sys__ksem_trywait_args /* {
675 1.1 christos semid_t id;
676 1.1 christos } */ *uap = v;
677 1.1 christos
678 1.1 christos return ksem_wait(l, SCARG(uap, id), 1);
679 1.1 christos }
680 1.1 christos
681 1.1 christos int
682 1.2 christos sys__ksem_getvalue(struct lwp *l, void *v, register_t *retval)
683 1.1 christos {
684 1.2 christos struct sys__ksem_getvalue_args /* {
685 1.1 christos semid_t id;
686 1.1 christos unsigned int *value;
687 1.1 christos } */ *uap = v;
688 1.3 thorpej struct ksem_proc *kp;
689 1.1 christos struct ksem *ks;
690 1.1 christos unsigned int val;
691 1.1 christos
692 1.3 thorpej if ((kp = l->l_proc->p_ksems) == NULL)
693 1.3 thorpej return (EINVAL);
694 1.3 thorpej
695 1.3 thorpej lockmgr(&kp->kp_lock, LK_SHARED, NULL);
696 1.3 thorpej ks = ksem_lookup_proc(kp, SCARG(uap, id));
697 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
698 1.3 thorpej if (ks == NULL)
699 1.1 christos return (EINVAL);
700 1.3 thorpej
701 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
702 1.1 christos val = ks->ks_value;
703 1.3 thorpej simple_unlock(&ks->ks_interlock);
704 1.3 thorpej
705 1.3 thorpej return (copyout(&val, SCARG(uap, value), sizeof(val)));
706 1.1 christos }
707 1.1 christos
708 1.1 christos int
709 1.2 christos sys__ksem_destroy(struct lwp *l, void *v, register_t *retval)
710 1.1 christos {
711 1.2 christos struct sys__ksem_destroy_args /*{
712 1.1 christos semid_t id;
713 1.1 christos } */ *uap = v;
714 1.3 thorpej struct ksem_proc *kp;
715 1.3 thorpej struct ksem_ref *ksr;
716 1.1 christos struct ksem *ks;
717 1.1 christos
718 1.3 thorpej if ((kp = l->l_proc->p_ksems) == NULL)
719 1.3 thorpej return (EINVAL);
720 1.3 thorpej
721 1.3 thorpej lockmgr(&kp->kp_lock, LK_EXCLUSIVE, NULL);
722 1.3 thorpej
723 1.3 thorpej ks = ksem_lookup_proc(kp, SCARG(uap, id));
724 1.3 thorpej if (ks == NULL) {
725 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
726 1.3 thorpej return (EINVAL);
727 1.3 thorpej }
728 1.3 thorpej
729 1.3 thorpej LOCK_ASSERT(simple_lock_held(&ks->ks_interlock));
730 1.3 thorpej
731 1.3 thorpej /*
732 1.3 thorpej * XXX This misses named semaphores which have been unlink'd,
733 1.3 thorpej * XXX but since behavior of destroying a named semaphore is
734 1.3 thorpej * XXX undefined, this is technically allowed.
735 1.3 thorpej */
736 1.3 thorpej if (ks->ks_name != NULL) {
737 1.3 thorpej simple_unlock(&ks->ks_interlock);
738 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
739 1.3 thorpej return (EINVAL);
740 1.3 thorpej }
741 1.3 thorpej
742 1.3 thorpej if (ks->ks_waiters) {
743 1.3 thorpej simple_unlock(&ks->ks_interlock);
744 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
745 1.3 thorpej return (EBUSY);
746 1.3 thorpej }
747 1.3 thorpej
748 1.3 thorpej ksr = ksem_drop_proc(kp, ks);
749 1.3 thorpej lockmgr(&kp->kp_lock, LK_RELEASE, NULL);
750 1.3 thorpej free(ksr, M_SEM);
751 1.3 thorpej
752 1.3 thorpej return (0);
753 1.3 thorpej }
754 1.3 thorpej
755 1.3 thorpej static void
756 1.3 thorpej ksem_forkhook(struct proc *p2, struct proc *p1)
757 1.3 thorpej {
758 1.3 thorpej struct ksem_proc *kp1, *kp2;
759 1.3 thorpej struct ksem_ref *ksr, *ksr1;
760 1.3 thorpej
761 1.3 thorpej if ((kp1 = p1->p_ksems) == NULL) {
762 1.3 thorpej p2->p_ksems = NULL;
763 1.3 thorpej return;
764 1.3 thorpej }
765 1.3 thorpej
766 1.3 thorpej p2->p_ksems = kp2 = ksem_proc_alloc();
767 1.3 thorpej
768 1.3 thorpej lockmgr(&kp1->kp_lock, LK_SHARED, NULL);
769 1.3 thorpej
770 1.3 thorpej if (!LIST_EMPTY(&kp1->kp_ksems)) {
771 1.3 thorpej LIST_FOREACH(ksr, &kp1->kp_ksems, ksr_list) {
772 1.3 thorpej ksr1 = malloc(sizeof(*ksr), M_SEM, M_WAITOK);
773 1.3 thorpej ksr1->ksr_ksem = ksr->ksr_ksem;
774 1.3 thorpej simple_lock(&ksr->ksr_ksem->ks_interlock);
775 1.3 thorpej ksem_addref(ksr->ksr_ksem);
776 1.3 thorpej simple_unlock(&ksr->ksr_ksem->ks_interlock);
777 1.3 thorpej LIST_INSERT_HEAD(&kp2->kp_ksems, ksr1, ksr_list);
778 1.3 thorpej }
779 1.1 christos }
780 1.3 thorpej
781 1.3 thorpej lockmgr(&kp1->kp_lock, LK_RELEASE, NULL);
782 1.1 christos }
783 1.1 christos
784 1.1 christos static void
785 1.8 fvdl ksem_exithook(struct proc *p, void *arg)
786 1.1 christos {
787 1.3 thorpej struct ksem_proc *kp;
788 1.3 thorpej struct ksem_ref *ksr;
789 1.3 thorpej
790 1.8 fvdl if ((kp = p->p_ksems) == NULL)
791 1.3 thorpej return;
792 1.1 christos
793 1.3 thorpej /* Don't bother locking; process is dying. */
794 1.3 thorpej
795 1.3 thorpej while ((ksr = LIST_FIRST(&kp->kp_ksems)) != NULL) {
796 1.3 thorpej LIST_REMOVE(ksr, ksr_list);
797 1.3 thorpej simple_lock(&ksr->ksr_ksem->ks_interlock);
798 1.3 thorpej ksem_delref(ksr->ksr_ksem);
799 1.3 thorpej free(ksr, M_SEM);
800 1.1 christos }
801 1.1 christos }
802 1.1 christos
803 1.1 christos void
804 1.1 christos ksem_init(void)
805 1.1 christos {
806 1.13 cube int i;
807 1.3 thorpej
808 1.1 christos simple_lock_init(&ksem_slock);
809 1.1 christos exithook_establish(ksem_exithook, NULL);
810 1.1 christos exechook_establish(ksem_exithook, NULL);
811 1.3 thorpej forkhook_establish(ksem_forkhook);
812 1.13 cube
813 1.13 cube for (i = 0; i < SEM_HASHTBL_SIZE; i++)
814 1.13 cube LIST_INIT(&ksem_hash[i]);
815 1.1 christos }
816