initial version

src/shmarea.c

@@ -0,0 +1,93 @@
+/*
+ *  IPC SHM area manager
+ *  Copyright (c) 2003 by Jaroslav Kysela <perex@suse.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"
+
+struct snd_shm_area {
+	struct list_head list;
+	int shmid;
+	void *ptr;
+	int share;
+};
+
+static LIST_HEAD(shm_areas);
+
+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;
+}
+
+struct snd_shm_area *snd_shm_area_share(struct snd_shm_area *area)
+{
+	if (area == NULL)
+		return NULL;
+	area->share++;
+	return area;
+}
+
+static void _x_destroy(struct snd_shm_area *area)
+{
+	struct shmid_ds buf;
+
+	shmdt(area->ptr);
+	if (shmctl(area->shmid, IPC_STAT, &buf) >= 0) {
+		if (buf.shm_nattch == 0)
+			shmctl(area->shmid, IPC_RMID, NULL);
+	}
+}
+
+int snd_shm_area_destroy(struct snd_shm_area *area)
+{
+	if (area == NULL)
+		return -ENOENT;
+	if (--area->share)
+		return 0;
+	list_del(&area->list);
+	_x_destroy(area);
+	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);
+		_x_destroy(area);
+	}
+}