136 lines
4.1 KiB
C
136 lines
4.1 KiB
C
/*
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* Copyright (C) 2023 Xiaomi Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <errno.h>
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#include <kvdb.h>
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#include <stdatomic.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/system_properties.h>
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struct system_property_foreach_cookie {
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void* __cookie;
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void (*__callback)(const prop_info* __pi, void* __cookie);
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};
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static uint32_t __system_property_serial_num = 0;
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/*
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* Sets system property `name` to `value`, creating the system property if it doesn't already exist.
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*/
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int __system_property_set(const char* __name, const char* __value)
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{
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int ret = property_set(__name, __value);
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if (ret >= 0)
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__system_property_serial_num++;
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return ret;
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}
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/*
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* Returns a `prop_info` corresponding system property `name`, or nullptr if it doesn't exist.
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* Use __system_property_read_callback to query the current value.
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*
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* Property lookup is expensive, so it can be useful to cache the result of this function.
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*/
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const prop_info* __system_property_find(const char* __name)
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{
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int ret = property_get(__name, NULL, NULL);
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if (ret < 0)
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return NULL;
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return (const prop_info*)__name;
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}
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/*
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* Calls `callback` with a consistent trio of name, value, and serial number for property `pi`.
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*/
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void __system_property_read_callback(const prop_info* __pi,
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void (*__callback)(void* __cookie, const char* __name, const char* __value, uint32_t __serial),
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void* __cookie)
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{
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char value[PROP_VALUE_MAX];
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if (__callback == NULL)
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return;
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int ret = property_get((const char*)__pi, value, NULL);
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if (ret < 0)
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return;
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__callback(__cookie, (const char*)__pi, value, __system_property_serial_num);
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}
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/*
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* used by __system_property_foreach() to pass to property_list.
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*/
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static void __system_property_foreach_callback(const char* key, const char* value, void* cookie)
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{
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struct system_property_foreach_cookie* pcookie = cookie;
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pcookie->__callback((const prop_info*)key, pcookie->__cookie);
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}
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/*
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* Iterates over each system property and invokes the provided callback.
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* Use __system_property_read_callback() to read property values.
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*
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* This function is mainly for inspecting and debugging the property system.
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*/
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int __system_property_foreach(void (*__callback)(const prop_info* __pi, void* __cookie), void* __cookie)
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{
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struct system_property_foreach_cookie cookie = {
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.__cookie = __cookie,
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.__callback = __callback};
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return property_list(__system_property_foreach_callback, &cookie);
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}
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/*
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* Waits for the system property `pi` to be updated past `old_serial`, with an optional timeout.
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* If `pi` is NULL, it waits for the global serial number.
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* If the serial is unknown, pass 0.
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*
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* Returns true if updated within the timeout, false if the call times out.
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*/
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bool __system_property_wait(const prop_info* __pi, uint32_t __old_serial, uint32_t* __new_serial_ptr, const struct timespec* __relative_timeout)
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{
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int timems = __relative_timeout->tv_sec * 1000 + __relative_timeout->tv_nsec / 1000000;
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int ret = property_wait(__pi ? (const char*)__pi : "*", NULL, NULL, 0, timems);
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if (ret >= 0) {
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if (__new_serial_ptr)
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*__new_serial_ptr = __system_property_serial_num;
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return true;
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}
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return false;
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}
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int __system_property_read(const prop_info* __pi, char* __name, char* __value)
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{
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strlcpy(__name, (const char*)__pi, PROP_NAME_MAX);
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return property_get(__name, __value, NULL);
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}
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int __system_property_get(const char* __name, char* __value)
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{
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return property_get(__name, __value, NULL);
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}
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