91 lines
3.9 KiB
C++
91 lines
3.9 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#pragma once
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#include <stdint.h>
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#include <sys/param.h>
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#include <sys/system_properties.h>
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#include "contexts.h"
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#include "contexts_pre_split.h"
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#include "contexts_serialized.h"
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#include "contexts_split.h"
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constexpr int PROP_FILENAME_MAX = 1024;
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class SystemProperties {
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public:
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friend struct LocalPropertyTestState;
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friend class SystemPropertiesTest;
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// Note that system properties are initialized before libc calls static initializers, so
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// doing any initialization in this constructor is an error. Even a Constructor that zero
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// initializes this class will clobber the previous property initialization.
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// We rely on the static SystemProperties in libc to be placed in .bss and zero initialized.
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SystemProperties() = default;
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// Special constructor for testing that also zero initializes the important members.
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explicit SystemProperties(bool initialized) : initialized_(initialized) {
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}
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DISALLOW_COPY_AND_ASSIGN(SystemProperties);
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bool Init(const char* filename);
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bool AreaInit(const char* filename, bool* fsetxattr_failed);
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uint32_t AreaSerial();
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const prop_info* Find(const char* name);
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int Read(const prop_info* pi, char* name, char* value);
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void ReadCallback(const prop_info* pi,
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void (*callback)(void* cookie, const char* name, const char* value,
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uint32_t serial),
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void* cookie);
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int Get(const char* name, char* value);
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int Update(prop_info* pi, const char* value, unsigned int len);
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int Add(const char* name, unsigned int namelen, const char* value, unsigned int valuelen);
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int Delete(const char *name);
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uint32_t Serial(const prop_info* pi);
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uint32_t WaitAny(uint32_t old_serial);
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bool Wait(const prop_info* pi, uint32_t old_serial, uint32_t* new_serial_ptr,
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const timespec* relative_timeout);
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const prop_info* FindNth(unsigned n);
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int Foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie);
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private:
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// We don't want to use new or malloc in properties (b/31659220), and we don't want to waste a
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// full page by using mmap(), so we set aside enough space to create any context of the three
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// contexts.
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static constexpr size_t kMaxContextsAlign =
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MAX(alignof(ContextsSerialized), MAX(alignof(ContextsSplit), alignof(ContextsPreSplit)));
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static constexpr size_t kMaxContextsSize =
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MAX(sizeof(ContextsSerialized), MAX(sizeof(ContextsSplit), sizeof(ContextsPreSplit)));
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alignas(kMaxContextsAlign) char contexts_data_[kMaxContextsSize];
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Contexts* contexts_;
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bool initialized_;
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char property_filename_[PROP_FILENAME_MAX];
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};
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