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+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _INCLUDE_LEGACY_PROPERTIES_H
+#define _INCLUDE_LEGACY_PROPERTIES_H
+
+#include <sys/system_properties.h>
+
+typedef struct prop_area prop_area;
+typedef struct prop_msg prop_msg;
+
+#define PROP_AREA_MAGIC 0x504f5250
+#define PROP_AREA_VERSION 0x45434f76
+
+#define PROP_SERVICE_NAME "property_service"
+
+/* #define PROP_MAX_ENTRIES 247 */
+/* 247 -> 32620 bytes (<32768) */
+
+#define TOC_NAME_LEN(toc) ((toc) >> 24)
+#define TOC_TO_INFO(area, toc) ((prop_info*) (((char*) area) + ((toc) & 0xFFFFFF)))
+
+struct prop_area {
+ unsigned volatile count;
+ unsigned volatile serial;
+ unsigned magic;
+ unsigned version;
+ unsigned reserved[4];
+ unsigned toc[1];
+};
+
+#define SERIAL_VALUE_LEN(serial) ((serial) >> 24)
+#define SERIAL_DIRTY(serial) ((serial) & 1)
+
+struct prop_info {
+ char name[PROP_NAME_MAX];
+ unsigned volatile serial;
+ char value[PROP_VALUE_MAX];
+};
+
+struct prop_msg
+{
+ unsigned cmd;
+ char name[PROP_NAME_MAX];
+ char value[PROP_VALUE_MAX];
+};
+
+#define PROP_MSG_SETPROP 1
+
+/*
+** Rules:
+**
+** - there is only one writer, but many readers
+** - prop_area.count will never decrease in value
+** - once allocated, a prop_info's name will not change
+** - once allocated, a prop_info's offset will not change
+** - reading a value requires the following steps
+** 1. serial = pi->serial
+** 2. if SERIAL_DIRTY(serial), wait*, then goto 1
+** 3. memcpy(local, pi->value, SERIAL_VALUE_LEN(serial) + 1)
+** 4. if pi->serial != serial, goto 2
+**
+** - writing a value requires the following steps
+** 1. pi->serial = pi->serial | 1
+** 2. memcpy(pi->value, local_value, value_len)
+** 3. pi->serial = (value_len << 24) | ((pi->serial + 1) & 0xffffff)
+**
+** Improvements:
+** - maintain the toc sorted by pi->name to allow lookup
+** by binary search
+**
+*/
+
+#define PROP_PATH_RAMDISK_DEFAULT "/default.prop"
+#define PROP_PATH_SYSTEM_BUILD "/system/build.prop"
+#define PROP_PATH_SYSTEM_DEFAULT "/system/default.prop"
+#define PROP_PATH_LOCAL_OVERRIDE "/data/local.prop"
+
+#endif