1 /* $NetBSD: sem.c,v 1.2 2003/03/09 00:44:43 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>. 41 * All rights reserved. 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(s), this list of conditions and the following disclaimer as 48 * the first lines of this file unmodified other than the possible 49 * addition of one or more copyright notices. 50 * 2. Redistributions in binary form must reproduce the above copyright 51 * notice(s), this list of conditions and the following disclaimer in 52 * the documentation and/or other materials provided with the 53 * distribution. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 56 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 58 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 59 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 60 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 61 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 62 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 63 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 64 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 65 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 66 */ 67 68 #include <sys/cdefs.h> 69 __RCSID("$NetBSD: sem.c,v 1.2 2003/03/09 00:44:43 lukem Exp $"); 70 71 /* 72 * If an application is linked against both librt and libpthread, the 73 * libpthread versions must be used. Provide weak aliases to cause 74 * this behavior. 75 */ 76 #define sem_init _librt_sem_init 77 #define sem_destroy _librt_sem_destroy 78 #define sem_open _librt_sem_open 79 #define sem_close _librt_sem_close 80 #define sem_unlink _librt_sem_unlink 81 #define sem_wait _librt_sem_wait 82 #define sem_trywait _librt_sem_trywait 83 #define sem_post _librt_sem_post 84 #define sem_getvalue _librt_sem_getvalue 85 86 #define _LIBC /* XXX to get semid_t type */ 87 88 #include <sys/types.h> 89 #include <sys/ksem.h> 90 #include <sys/queue.h> 91 #include <stdlib.h> 92 #include <errno.h> 93 #include <fcntl.h> 94 #include <semaphore.h> 95 #include <stdarg.h> 96 97 struct _sem_st { 98 unsigned int ksem_magic; 99 #define KSEM_MAGIC 0x90af0421U 100 101 LIST_ENTRY(_sem_st) ksem_list; 102 semid_t ksem_semid; /* 0 -> user (non-shared) */ 103 sem_t *ksem_identity; 104 }; 105 106 static int sem_alloc(unsigned int value, semid_t semid, sem_t *semp); 107 static void sem_free(sem_t sem); 108 109 static LIST_HEAD(, _sem_st) named_sems = LIST_HEAD_INITIALIZER(&named_sems); 110 111 __weak_alias(sem_init,_librt_sem_init) 112 __weak_alias(sem_destroy,_librt_sem_destroy) 113 __weak_alias(sem_open,_librt_sem_open) 114 __weak_alias(sem_close,_librt_sem_close) 115 __weak_alias(sem_unlink,_librt_sem_unlink) 116 __weak_alias(sem_wait,_librt_sem_wait) 117 __weak_alias(sem_trywait,_librt_sem_trywait) 118 __weak_alias(sem_post,_librt_sem_post) 119 __weak_alias(sem_getvalue,_librt_sem_getvalue) 120 121 static void 122 sem_free(sem_t sem) 123 { 124 125 sem->ksem_magic = 0; 126 free(sem); 127 } 128 129 static int 130 sem_alloc(unsigned int value, semid_t semid, sem_t *semp) 131 { 132 sem_t sem; 133 134 if (value > SEM_VALUE_MAX) 135 return (EINVAL); 136 137 if ((sem = malloc(sizeof(struct _sem_st))) == NULL) 138 return (ENOSPC); 139 140 sem->ksem_magic = KSEM_MAGIC; 141 sem->ksem_semid = semid; 142 143 *semp = sem; 144 return (0); 145 } 146 147 /* ARGSUSED */ 148 int 149 sem_init(sem_t *sem, int pshared, unsigned int value) 150 { 151 semid_t semid; 152 int error; 153 154 if (_ksem_init(value, &semid) == -1) 155 return (-1); 156 157 if ((error = sem_alloc(value, semid, sem)) != 0) { 158 _ksem_destroy(semid); 159 errno = error; 160 return (-1); 161 } 162 163 return (0); 164 } 165 166 int 167 sem_destroy(sem_t *sem) 168 { 169 170 #ifdef ERRORCHECK 171 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 172 errno = EINVAL; 173 return (-1); 174 } 175 #endif 176 177 if (_ksem_destroy((*sem)->ksem_semid) == -1) 178 return (-1); 179 180 sem_free(*sem); 181 182 return (0); 183 } 184 185 sem_t * 186 sem_open(const char *name, int oflag, ...) 187 { 188 sem_t *sem, s; 189 semid_t semid; 190 mode_t mode; 191 unsigned int value; 192 int error; 193 va_list ap; 194 195 mode = 0; 196 value = 0; 197 198 if (oflag & O_CREAT) { 199 va_start(ap, oflag); 200 mode = va_arg(ap, int); 201 value = va_arg(ap, unsigned int); 202 va_end(ap); 203 } 204 205 /* 206 * We can be lazy and let the kernel handle the oflag, 207 * we'll just merge duplicate IDs into our list. 208 */ 209 if (_ksem_open(name, oflag, mode, value, &semid) == -1) 210 return (SEM_FAILED); 211 212 /* 213 * Search for a duplicate ID, we must return the same sem_t * 214 * if we locate one. 215 */ 216 LIST_FOREACH(s, &named_sems, ksem_list) { 217 if (s->ksem_semid == semid) 218 return (s->ksem_identity); 219 } 220 221 if ((sem = malloc(sizeof(*sem))) == NULL) { 222 error = ENOSPC; 223 goto bad; 224 } 225 if ((error = sem_alloc(value, semid, sem)) != 0) 226 goto bad; 227 228 LIST_INSERT_HEAD(&named_sems, *sem, ksem_list); 229 (*sem)->ksem_identity = sem; 230 231 return (sem); 232 233 bad: 234 _ksem_close(semid); 235 if (sem != NULL) { 236 if (*sem != NULL) 237 sem_free(*sem); 238 free(sem); 239 } 240 errno = error; 241 return (SEM_FAILED); 242 } 243 244 int 245 sem_close(sem_t *sem) 246 { 247 248 #ifdef ERRORCHECK 249 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 250 errno = EINVAL; 251 return (-1); 252 } 253 #endif 254 255 if (_ksem_close((*sem)->ksem_semid) == -1) 256 return (-1); 257 258 LIST_REMOVE((*sem), ksem_list); 259 sem_free(*sem); 260 free(sem); 261 return (0); 262 } 263 264 int 265 sem_unlink(const char *name) 266 { 267 268 return (_ksem_unlink(name)); 269 } 270 271 int 272 sem_wait(sem_t *sem) 273 { 274 275 #ifdef ERRORCHECK 276 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 277 errno = EINVAL; 278 return (-1); 279 } 280 #endif 281 282 return (_ksem_wait((*sem)->ksem_semid)); 283 } 284 285 int 286 sem_trywait(sem_t *sem) 287 { 288 289 #ifdef ERRORCHECK 290 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 291 errno = EINVAL; 292 return (-1); 293 } 294 #endif 295 296 return (_ksem_trywait((*sem)->ksem_semid)); 297 } 298 299 int 300 sem_post(sem_t *sem) 301 { 302 303 #ifdef ERRORCHECK 304 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 305 errno = EINVAL; 306 return (-1); 307 } 308 #endif 309 310 return (_ksem_post((*sem)->ksem_semid)); 311 } 312 313 int 314 sem_getvalue(sem_t * __restrict sem, int * __restrict sval) 315 { 316 317 #ifdef ERRORCHECK 318 if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) { 319 errno = EINVAL; 320 return (-1); 321 } 322 #endif 323 return (_ksem_getvalue((*sem)->ksem_semid, sval)); 324 } 325