#include <stddef.h>

#include <sys/mman.h>

#include "moar.h"

#include "platform/mmap.h"

#include <errno.h>

/* MAP_ANONYMOUS is Linux, MAP_ANON is BSD */

#ifndef MVM_MAP_ANON

#if defined(MAP_ANONYMOUS)

#define MVM_MAP_ANON MAP_ANONYMOUS

#elif defined(MAP_ANON)

#define MVM_MAP_ANON MAP_ANON

#else

#error "Anonymous mmap() not supported. You need to define MVM_MAP_ANON manually if it is."

#endif

#endif

static int page_mode_to_prot_mode(int page_mode) {

    switch (page_mode) {

    case MVM_PAGE_READ:

        return PROT_READ;

    case MVM_PAGE_WRITE:

        return PROT_WRITE;

    case (MVM_PAGE_READ|MVM_PAGE_WRITE):

        return PROT_READ|PROT_WRITE;

    case MVM_PAGE_EXEC:

        return PROT_EXEC;

    case (MVM_PAGE_READ|MVM_PAGE_EXEC):

        return PROT_READ|PROT_EXEC;

    case (MVM_PAGE_WRITE|MVM_PAGE_EXEC):

        return PROT_WRITE|PROT_EXEC;

    case (MVM_PAGE_READ|MVM_PAGE_WRITE|MVM_PAGE_EXEC):

        return PROT_READ|PROT_WRITE|PROT_EXEC;

    default:

        return PROT_NONE;

    }

}

void *MVM_platform_alloc_pages(size_t size, int page_mode)

{

    int prot_mode = page_mode_to_prot_mode(page_mode);

    void *block = mmap(NULL, size, prot_mode, MVM_MAP_ANON | MAP_PRIVATE, -1, 0);

    if (block == MAP_FAILED)

        MVM_panic(1, "MVM_platform_alloc_pages failed: %d", errno);

    return block;

}

int MVM_platform_set_page_mode(void * block, size_t size, int page_mode) {

    int prot_mode = page_mode_to_prot_mode(page_mode);

    return mprotect(block, size, prot_mode) == 0;

}

int MVM_platform_free_pages(void *block, size_t size)

{

    return munmap(block, size) == 0;

}

void *MVM_platform_map_file(int fd, void **handle, size_t size, int writable)

{

    void *block = mmap(NULL, size,

        writable ? PROT_READ | PROT_WRITE : PROT_READ,

        writable ? MAP_SHARED : MAP_PRIVATE, fd, 0);

    (void)handle;

    return block != MAP_FAILED ? block : NULL;

}

int MVM_platform_unmap_file(void *block, void *handle, size_t size)

{

    (void)handle;

    return munmap(block, size) == 0;

}