root/Whitix/trunk/memory/shmem.c

/*  This file is part of Whitix.
 *
 *  Whitix is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Whitix is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Whitix; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <fs/vfs.h>
#include <vmm.h>
#include <llist.h>
#include <malloc.h>
#include <typedefs.h>
#include <i386/i386.h>
#include <slab.h>
#include <user_acc.h>
#include <sys.h>
#include <module.h>
#include <print.h>

#define SHMEM_MAX_DESCS         10

struct SharedMemoryDesc
{
        int creatorPid;
        DWORD size;
        DWORD* pages;
};

struct SharedMemoryDesc* shMemDescs[SHMEM_MAX_DESCS];

int ShMemNoPage(struct VMArea* area, DWORD address, DWORD offset);
int ShMemAddPage(struct VMArea* area, DWORD address);

struct VmAreaOps shMemOps=
{
        .handleNoPage = ShMemNoPage,
        .addPage = ShMemAddPage,
};

static struct SharedMemoryDesc* ShMemGetDesc(int i)
{
        if (i < 0 || i >= SHMEM_MAX_DESCS)
                return NULL;

        return shMemDescs[i];
}

int SharedMemCreate(size_t size, int flags)
{
        int numPages=PAGE_ALIGN_UP(size) >> PAGE_SHIFT;
        int i, id;
        struct SharedMemoryDesc* shDesc;

        if (!numPages)
                return -EINVAL;

        /* Find an empty shared memory description slot. */
        for (i=0; i<SHMEM_MAX_DESCS; i++)
                /* Descriptor slot not occupied? */
                if (!shMemDescs[i])
                        break;

        if (i == SHMEM_MAX_DESCS)
                return -EMFILE;

        shMemDescs[i]=shDesc=(struct SharedMemoryDesc*)MemAlloc(sizeof(struct SharedMemoryDesc));

        id=i;

        if (!shDesc)
                return -ENOMEM;

        /* Fill in the shared memory descriptor */
        shDesc->size=PAGE_ALIGN_UP(size);
        shDesc->pages=(DWORD*)MemAlloc(sizeof(DWORD)*numPages);

        if (!shDesc->pages)
                return -ENOMEM;

        for (i=0; i<numPages; i++)
                shDesc->pages[i]=0;

        return id+1;
}

int SysSharedMemoryGet(unsigned int key, size_t size, int flags)
{
//      KePrint("SysSharedMemoryGet(%d, %u)\n", key, size);
        if (key == 0)
                return SharedMemCreate(size, flags);
        else{
                KePrint("SysSharedMemoryGet: key > 0\n");
                return -EINVAL;
        }

        return 0;
}

DWORD SysSharedMemoryAttach(int id, DWORD address, int flags)
{
        struct SharedMemoryDesc* desc=ShMemGetDesc(id-1);

//      KePrint("%s: SysSharedMemoryAttach(%d, %#X), %#X, size = %#X\n", current->name, id, address, desc, desc->size);

        if (!desc)
                return 0;

        return MMapDo(current, NULL, address, desc->size, 7, 0, MMAP_PRIVATE, &shMemOps);
}

/* FIXME: Rewrite. */
struct SharedMemoryDesc* ShMemFind(DWORD length)
{
        /* FIXME: Have private field for VMArea. */
        int i=0;

        for (i=0; i<SHMEM_MAX_DESCS; i++)
        {
                /* FIXME: Hack! */
                if (shMemDescs[i] && shMemDescs[i]->size == length)
                        break;
        }

        if (i == SHMEM_MAX_DESCS)
                return NULL;

        return shMemDescs[i];
}

int ShMemAddPage(struct VMArea* area, DWORD address)
{
        struct SharedMemoryDesc* shMem=ShMemFind(area->length);
        int pageIndex=(address-area->start) >> PAGE_SHIFT;

//      KePrint("pageIndex = %d\n", pageIndex);

        if (!shMem)
                return -EFAULT;

        while (1);

        return 0;
}

/* TODO: Try to merge with the general mmap code perhaps? */
int ShMemNoPage(struct VMArea* area, DWORD address, DWORD offset)
{
        int pageIndex=offset >> PAGE_SHIFT;
        struct SharedMemoryDesc* shMem=ShMemFind(area->length);

        if (!shMem)
                return -EFAULT;

        if (!shMem->pages[pageIndex])
                shMem->pages[pageIndex]=PageAlloc()->physAddr;

//      KePrint("%s: ShMemNoPage(%d) = %#X\n", current->name, pageIndex, shMem->pages[pageIndex]);

        /* HACK: Need to have flag and reconsider whether should map here. */
        struct VNode* vNode;

        NameToVNode(&vNode,DEVICES_PATH "Special/Zero",0, NULL);

        if (area->vNode->id == vNode->id)
        {
                VirtMemMapPage(address, shMem->pages[pageIndex], 7);
                return 0;
        }

        return -EFAULT;
}

int SysSharedMemoryControl(int id, int command, void* buffer)
{
        KePrint("SysSharedMemoryControl(%d)\n", id);
        return 0;
}

int SysSharedMemoryDetach(const void* address)
{
        KePrint("SysSharedMemoryDetach(%#X)\n", address);
        return 0;
}

struct SysCall shMemSysCalls[]=
{
        SysEntry(SysSharedMemoryGet, 12),
        SysEntry(SysSharedMemoryAttach, 12),
        SysEntry(SysSharedMemoryControl, 12),
        SysEntry(SysSharedMemoryDetach, 4),
        SysEntryEnd(),
};

int ShMemInit()
{
        SysRegisterRange(SYS_SHMEM_BASE, shMemSysCalls);
        return 0;
}

ModuleInit(ShMemInit);