Shared Memory

Shared Memory. More...

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Detailed Description

Shared Memory.

Shared memory is exposed in the /dev/shmem directory. Shared memory allows multiple processes to share a section of memory for inter-process communication (IPC).

Creating Shared Memory

Shared memory objects are created using the /dev/shmem/new file. Opening this file using open() will create a new anonymous shared memory object and return a file descriptor to it.

Using Shared Memory

Shared memory objects can be mapped to the current process's address space using the mmap() system call. The first call to mmap() will decide the size of the shared memory object. Subsequent calls to mmap() will map the existing shared memory object.

Data Structures
struct	shmem_object_t
	Represents a shared memory object. More...

Functions
static void	shmem_object_free (shmem_object_t *shmem)
static shmem_object_t *	shmem_object_new (void)
static void	shmem_vmm_callback (void *private)
static void *	shmem_object_allocate_pages (shmem_object_t *shmem, uint64_t pageAmount, space_t *space, void *address, pml_flags_t flags)
static uint64_t	shmem_open (file_t *file)
static void	shmem_close (file_t *file)
static void *	shmem_mmap (file_t *file, void *address, size_t length, size_t *offset, pml_flags_t flags)
static uint64_t	shmem_init (void)
static void	shmem_deinit (void)

Variables
static dentry_t *	shmemDir = NULL
static dentry_t *	newFile = NULL
static file_ops_t	fileOps

Function Documentation

shmem_object_free()

static void shmem_object_free ( shmem_object_t *  shmem )

static

Definition at line 54 of file shmem.c.

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shmem_object_new()

static shmem_object_t * shmem_object_new ( void  )

static

Definition at line 74 of file shmem.c.

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shmem_vmm_callback()

static void shmem_vmm_callback ( void *  private )

static

Definition at line 89 of file shmem.c.

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shmem_object_allocate_pages()

static void * shmem_object_allocate_pages ( shmem_object_t *  shmem, uint64_t  pageAmount, space_t *  space, void *  address, pml_flags_t  flags  )

static

Definition at line 100 of file shmem.c.

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shmem_open()

static uint64_t shmem_open ( file_t *  file )

static

Definition at line 145 of file shmem.c.

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shmem_close()

static void shmem_close ( file_t *  file )

static

Definition at line 157 of file shmem.c.

shmem_mmap()

static void * shmem_mmap ( file_t *  file, void *  address, size_t  length, size_t *  offset, pml_flags_t  flags  )

static

Definition at line 168 of file shmem.c.

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shmem_init()

static uint64_t shmem_init ( void  )

static

Definition at line 229 of file shmem.c.

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shmem_deinit()

static void shmem_deinit ( void  )

static

Definition at line 249 of file shmem.c.

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Variable Documentation

shmemDir

dentry_t* shmemDir = NULL

static

Definition at line 51 of file shmem.c.

newFile

dentry_t* newFile = NULL

static

Definition at line 52 of file shmem.c.

fileOps

file_ops_t fileOps

static

Initial value:

= {
    .open = shmem_open,
    .close = shmem_close,
    .mmap = shmem_mmap,
}

Definition at line 223 of file shmem.c.