MaxOS::processes::SharedMemory Class Reference

A block memory that is mapped into multiple processes. More...

#include <ipc.h>

Inheritance diagram for MaxOS::processes::SharedMemory:

Public Member Functions
	SharedMemory (const string &name, size_t size, resources::resource_type_t type)
	Creates a new shared memory block.
void	open (size_t flags) final
	Map the shared memory into the address space of the owning process.
void	close (size_t flags) final
	Frees the page containing the shared memory.
int	read (void *buffer, size_t size, size_t flags) final
	Get the address that the current process has this shared memory mapped to.
uintptr_t	physical_address () const
	Gets the physical address of the shared memory block.
size_t	size () const
	Gets the size of the shared memory block.

Detailed Description

A block memory that is mapped into multiple processes.

Definition at line 45 of file ipc.h.

Constructor & Destructor Documentation

SharedMemory()

SharedMemory::SharedMemory	(	const string &	name,
		size_t	size,
		resources::resource_type_t	type
	)

Creates a new shared memory block.

Parameters

name	The name of the block
size	The size of the shared memory region
type	The type of resource

Definition at line 30 of file ipc.cpp.

: Resource(name, size, MaxOS::KPI::ResourceType::SHARED_MEMORY),
  m_size(size)
{
    m_physical_address = (uintptr_t) PhysicalMemoryManager::s_current_manager->allocate_area(0, size);
}

References MaxOS::memory::PhysicalMemoryManager::s_current_manager, and size().

Member Function Documentation

close()

void SharedMemory::close ( size_t  flags )

final

Frees the page containing the shared memory.

Parameters

flags

Not used for this resource

Definition at line 99 of file ipc.cpp.

                                     {
 
    PhysicalMemoryManager::s_current_manager->free_area(m_physical_address, m_size);
 
}

References MaxOS::memory::PhysicalMemoryManager::free_area(), and MaxOS::memory::PhysicalMemoryManager::s_current_manager.

open()

void SharedMemory::open ( size_t  flags )

final

Map the shared memory into the address space of the owning process.

Parameters

flags

Not used for this resource

Definition at line 82 of file ipc.cpp.

                                    {
 
    // Process has already opened this memory
    auto it = m_mappings.find(GlobalScheduler::current_process()->pid());
    if(it != m_mappings.end())
        return;
 
    auto virtual_address = (uintptr_t)GlobalScheduler::current_process()->memory_manager->vmm()->load_shared_memory(m_physical_address, m_size);
    m_mappings.insert(GlobalScheduler::current_process()->pid(), virtual_address);
 
}

References MaxOS::processes::GlobalScheduler::current_process(), MaxOS::memory::VirtualMemoryManager::load_shared_memory(), MaxOS::processes::Process::memory_manager, MaxOS::processes::Process::pid(), and MaxOS::memory::BumpMemoryManager::vmm().

physical_address()

uintptr_t SharedMemory::physical_address

(

)

const

Gets the physical address of the shared memory block.

Returns

The physical address

Definition at line 62 of file ipc.cpp.

                                               {
 
    return m_physical_address;
}

read()

int SharedMemory::read ( void *  buffer, size_t  size, size_t  flags  )

final

Get the address that the current process has this shared memory mapped to.

Parameters

buffer	Not used
size	Not used
flags	Not used

Returns

The virtual address in the current process's address space or 0 if not found

Definition at line 47 of file ipc.cpp.

                                                              {
 
    // Process hasn't opened the resource
    auto it = m_mappings.find(GlobalScheduler::current_process()->pid());
    if(it == m_mappings.end())
        return 0;
 
    return it->second;
}

References MaxOS::processes::GlobalScheduler::current_process().

size()

size_t SharedMemory::size

(

)

const

Gets the size of the shared memory block.

Returns

The size

Definition at line 72 of file ipc.cpp.

                                {
 
    return m_size;
}

Referenced by SharedMemory().

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The documentation for this class was generated from the following files:

• /home/runner/work/MaxOS/MaxOS/kernel/include/processes/ipc.h
• /home/runner/work/MaxOS/MaxOS/kernel/src/processes/ipc.cpp