17c79a9e23
Besides adapting the components to the use of base/log.h, the patch cleans up a few base headers, i.e., it removes unused includes from root/component.h, specifically base/heap.h and ram_session/ram_session.h. Hence, components that relied on the implicit inclusion of those headers have to manually include those headers now. While adjusting the log messages, I repeatedly stumbled over the problem that printing char * arguments is ambiguous. It is unclear whether to print the argument as pointer or null-terminated string. To overcome this problem, the patch introduces a new type 'Cstring' that allows the caller to express that the argument should be handled as null-terminated string. As a nice side effect, with this type in place, the optional len argument of the 'String' class could be removed. Instead of supplying a pair of (char const *, size_t), the constructor accepts a 'Cstring'. This, in turn, clears the way let the 'String' constructor use the new output mechanism to assemble a string from multiple arguments (and thereby getting rid of snprintf within Genode in the near future). To enforce the explicit resolution of the char * ambiguity, the 'char *' overload of the 'print' function is marked as deleted. Issue #1987
114 lines
2.7 KiB
C++
114 lines
2.7 KiB
C++
/*
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* \brief A guard for arbitrary allocators to limit memory exhaustion
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* \author Stefan Kalkowski
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* \date 2010-08-20
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*/
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/*
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* Copyright (C) 2010-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__BASE__ALLOCATOR_GUARD_H_
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#define _INCLUDE__BASE__ALLOCATOR_GUARD_H_
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#include <base/allocator.h>
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#include <base/log.h>
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#include <base/stdint.h>
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namespace Genode { class Allocator_guard; }
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/**
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* This class acts as guard for arbitrary allocators to limit
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* memory exhaustion
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*/
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class Genode::Allocator_guard : public Allocator
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{
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private:
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Allocator *_allocator; /* allocator to guard */
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size_t _amount; /* total amount */
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size_t _consumed; /* already consumed bytes */
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public:
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Allocator_guard(Allocator *allocator, size_t amount)
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: _allocator(allocator), _amount(amount), _consumed(0) { }
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/**
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* Extend allocation limit
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*/
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void upgrade(size_t additional_amount) {
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_amount += additional_amount; }
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/**
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* Consume bytes without actually allocating them
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*/
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bool withdraw(size_t size)
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{
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if ((_amount - _consumed) < size)
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return false;
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_consumed += size;
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return true;
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}
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/*************************
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** Allocator interface **
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*************************/
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/**
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* Allocate block
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*
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* \param size block size to allocate
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* \param out_addr resulting pointer to the new block,
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* undefined in the error case
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* \return true on success
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*/
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bool alloc(size_t size, void **out_addr) override
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{
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if ((_amount - _consumed) < (size + _allocator->overhead(size))) {
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warning("Quota exceeded! amount=", _amount,
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", size=", (size + _allocator->overhead(size)),
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", consumed=", _consumed);
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return false;
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}
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bool const b = _allocator->alloc(size, out_addr);
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if (b)
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_consumed += size + _allocator->overhead(size);
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return b;
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}
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/**
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* Free block a previously allocated block
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*/
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void free(void *addr, size_t size) override
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{
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_allocator->free(addr, size);
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_consumed -= size + _allocator->overhead(size);
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}
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/**
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* Return amount of backing store consumed by the allocator
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*/
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size_t consumed() const override { return _consumed; }
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/**
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* Return allocation limit
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*/
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size_t quota() const { return _amount; }
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/**
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* Return meta-data overhead per block
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*/
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size_t overhead(size_t size) const override { return _allocator->overhead(size); }
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bool need_size_for_free() const override {
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return _allocator->need_size_for_free(); }
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};
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#endif /* _INCLUDE__BASE__ALLOCATOR_GUARD_H_ */
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