| /* |
| * IPC SHM area manager |
| * Copyright (c) 2003 by Jaroslav Kysela <perex@perex.cz> |
| * |
| * This library is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU Lesser General Public License as |
| * published by the Free Software Foundation; either version 2.1 of |
| * the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| |
| #include <stdio.h> |
| #include <malloc.h> |
| #include <string.h> |
| #include <errno.h> |
| #include <sys/poll.h> |
| #include <sys/mman.h> |
| #include <sys/shm.h> |
| #include "list.h" |
| |
| #ifndef DOC_HIDDEN |
| struct snd_shm_area { |
| struct list_head list; |
| int shmid; |
| void *ptr; |
| int share; |
| }; |
| #endif |
| |
| static LIST_HEAD(shm_areas); |
| |
| /** |
| * \brief Create a shm area record |
| * \param shmid IPC SHM ID |
| * \param ptr the shared area pointer |
| * \return The allocated shm area record, NULL if fail |
| * |
| * Allocates a shared area record with the given SHM ID and pointer. |
| * The record has a reference counter, which is initialized to 1 by this function. |
| */ |
| struct snd_shm_area *snd_shm_area_create(int shmid, void *ptr) |
| { |
| struct snd_shm_area *area = malloc(sizeof(*area)); |
| if (area) { |
| area->shmid = shmid; |
| area->ptr = ptr; |
| area->share = 1; |
| list_add_tail(&area->list, &shm_areas); |
| } |
| return area; |
| } |
| |
| /** |
| * \brief Increase the reference counter of shm area record |
| * \param area shm area record |
| * \return the shm area record (identical with the argument) |
| * |
| * Increases the reference counter of the given shared area record. |
| */ |
| struct snd_shm_area *snd_shm_area_share(struct snd_shm_area *area) |
| { |
| if (area == NULL) |
| return NULL; |
| area->share++; |
| return area; |
| } |
| |
| /** |
| * \brief Release the shared area record |
| * \param area the shared are record |
| * \return 0 if successful, or a negative error code |
| * |
| * Decreases the reference counter of the given shared area record, and |
| * releases the resources automaticall if it reaches to 0. |
| */ |
| int snd_shm_area_destroy(struct snd_shm_area *area) |
| { |
| if (area == NULL) |
| return -ENOENT; |
| if (--area->share) |
| return 0; |
| list_del(&area->list); |
| shmdt(area->ptr); |
| free(area); |
| return 0; |
| } |
| |
| void snd_shm_area_destructor(void) __attribute__ ((destructor)); |
| |
| void snd_shm_area_destructor(void) |
| { |
| struct list_head *pos; |
| struct snd_shm_area *area; |
| |
| list_for_each(pos, &shm_areas) { |
| area = list_entry(pos, struct snd_shm_area, list); |
| shmdt(area->ptr); |
| } |
| } |