/*
 * Unix interface for virtual memory functions
 *
 * Copyright (C) 2020 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#if 0
#pragma makedep unix
#endif

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <stdarg.h>
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif
#if defined(__APPLE__)
# include <mach/mach_init.h>
# include <mach/mach_vm.h>
#endif

#include <stdio.h>

#include "ntstatus.h"
#define WIN32_NO_STATUS
#define NONAMELESSUNION
#define NONAMELESSSTRUCT
#include "windef.h"
#include "winnt.h"
#include "winternl.h"
#include "unix_private.h"
#include "wine/list.h"

struct preload_info
{
    void  *addr;
    size_t size;
};

struct reserved_area
{
    struct list entry;
    void       *base;
    size_t      size;
};

static struct list reserved_areas = LIST_INIT(reserved_areas);

static const unsigned int granularity_mask = 0xffff;  /* reserved areas have 64k granularity */

extern IMAGE_NT_HEADERS __wine_spec_nt_header;

#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
#ifndef MAP_TRYFIXED
#define MAP_TRYFIXED 0
#endif


static void reserve_area( void *addr, void *end )
{
#ifdef __APPLE__

#ifdef __i386__
    static const mach_vm_address_t max_address = VM_MAX_ADDRESS;
#else
    static const mach_vm_address_t max_address = MACH_VM_MAX_ADDRESS;
#endif
    mach_vm_address_t address = (mach_vm_address_t)addr;
    mach_vm_address_t end_address = (mach_vm_address_t)end;

    if (!end_address || max_address < end_address)
        end_address = max_address;

    while (address < end_address)
    {
        mach_vm_address_t hole_address = address;
        kern_return_t ret;
        mach_vm_size_t size;
        vm_region_basic_info_data_64_t info;
        mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT_64;
        mach_port_t dummy_object_name = MACH_PORT_NULL;

        /* find the mapped region at or above the current address. */
        ret = mach_vm_region(mach_task_self(), &address, &size, VM_REGION_BASIC_INFO_64,
                             (vm_region_info_t)&info, &count, &dummy_object_name);
        if (ret != KERN_SUCCESS)
        {
            address = max_address;
            size = 0;
        }

        if (end_address < address)
            address = end_address;
        if (hole_address < address)
        {
            /* found a hole, attempt to reserve it. */
            size_t hole_size = address - hole_address;
            mach_vm_address_t alloc_address = hole_address;

            ret = mach_vm_map( mach_task_self(), &alloc_address, hole_size, 0, VM_FLAGS_FIXED,
                               MEMORY_OBJECT_NULL, 0, 0, PROT_NONE, VM_PROT_ALL, VM_INHERIT_COPY );
            if (!ret) mmap_add_reserved_area( (void*)hole_address, hole_size );
            else if (ret == KERN_NO_SPACE)
            {
                /* something filled (part of) the hole before we could.
                   go back and look again. */
                address = hole_address;
                continue;
            }
        }
        address += size;
    }
#else
    void *ptr;
    int flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE | MAP_TRYFIXED;
    size_t size = (char *)end - (char *)addr;

    if (!size) return;

#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
    ptr = mmap( addr, size, PROT_NONE, flags | MAP_FIXED | MAP_EXCL, -1, 0 );
#else
    ptr = mmap( addr, size, PROT_NONE, flags, -1, 0 );
#endif
    if (ptr == addr)
    {
        mmap_add_reserved_area( addr, size );
        return;
    }
    if (ptr != (void *)-1) munmap( ptr, size );

    size = (size / 2) & ~granularity_mask;
    if (size)
    {
        reserve_area( addr, (char *)addr + size );
        reserve_area( (char *)addr + size, end );
    }
#endif /* __APPLE__ */
}


static void mmap_init( const struct preload_info *preload_info )
{
#ifdef __i386__
#ifndef __APPLE__
    char stack;
    char * const stack_ptr = &stack;
#endif
    char *user_space_limit = (char *)0x7ffe0000;
    int i;

    if (preload_info)
    {
        /* check for a reserved area starting at the user space limit */
        /* to avoid wasting time trying to allocate it again */
        for (i = 0; preload_info[i].size; i++)
        {
            if ((char *)preload_info[i].addr > user_space_limit) break;
            if ((char *)preload_info[i].addr + preload_info[i].size > user_space_limit)
            {
                user_space_limit = (char *)preload_info[i].addr + preload_info[i].size;
                break;
            }
        }
    }
    else reserve_area( (void *)0x00010000, (void *)0x40000000 );


#ifndef __APPLE__
    if (stack_ptr >= user_space_limit)
    {
        char *end = 0;
        char *base = stack_ptr - ((unsigned int)stack_ptr & granularity_mask) - (granularity_mask + 1);
        if (base > user_space_limit) reserve_area( user_space_limit, base );
        base = stack_ptr - ((unsigned int)stack_ptr & granularity_mask) + (granularity_mask + 1);
#if defined(linux) || defined(__FreeBSD__) || defined (__FreeBSD_kernel__) || defined(__DragonFly__)
        /* Heuristic: assume the stack is near the end of the address */
        /* space, this avoids a lot of futile allocation attempts */
        end = (char *)(((unsigned long)base + 0x0fffffff) & 0xf0000000);
#endif
        reserve_area( base, end );
    }
    else
#endif
        reserve_area( user_space_limit, 0 );

#elif defined(__x86_64__) || defined(__aarch64__)

    if (preload_info) return;
    /* if we don't have a preloader, try to reserve the space now */
    reserve_area( (void *)0x000000010000, (void *)0x000068000000 );
    reserve_area( (void *)0x00007ff00000, (void *)0x00007fff0000 );
    reserve_area( (void *)0x7ffffe000000, (void *)0x7fffffff0000 );

#endif
}

void CDECL mmap_add_reserved_area( void *addr, SIZE_T size )
{
    struct reserved_area *area;
    struct list *ptr;

    if (!((char *)addr + size)) size--;  /* avoid wrap-around */

    LIST_FOR_EACH( ptr, &reserved_areas )
    {
        area = LIST_ENTRY( ptr, struct reserved_area, entry );
        if (area->base > addr)
        {
            /* try to merge with the next one */
            if ((char *)addr + size == (char *)area->base)
            {
                area->base = addr;
                area->size += size;
                return;
            }
            break;
        }
        else if ((char *)area->base + area->size == (char *)addr)
        {
            /* merge with the previous one */
            area->size += size;

            /* try to merge with the next one too */
            if ((ptr = list_next( &reserved_areas, ptr )))
            {
                struct reserved_area *next = LIST_ENTRY( ptr, struct reserved_area, entry );
                if ((char *)addr + size == (char *)next->base)
                {
                    area->size += next->size;
                    list_remove( &next->entry );
                    free( next );
                }
            }
            return;
        }
    }

    if ((area = malloc( sizeof(*area) )))
    {
        area->base = addr;
        area->size = size;
        list_add_before( ptr, &area->entry );
    }
}

void CDECL mmap_remove_reserved_area( void *addr, SIZE_T size )
{
    struct reserved_area *area;
    struct list *ptr;

    if (!((char *)addr + size)) size--;  /* avoid wrap-around */

    ptr = list_head( &reserved_areas );
    /* find the first area covering address */
    while (ptr)
    {
        area = LIST_ENTRY( ptr, struct reserved_area, entry );
        if ((char *)area->base >= (char *)addr + size) break;  /* outside the range */
        if ((char *)area->base + area->size > (char *)addr)  /* overlaps range */
        {
            if (area->base >= addr)
            {
                if ((char *)area->base + area->size > (char *)addr + size)
                {
                    /* range overlaps beginning of area only -> shrink area */
                    area->size -= (char *)addr + size - (char *)area->base;
                    area->base = (char *)addr + size;
                    break;
                }
                else
                {
                    /* range contains the whole area -> remove area completely */
                    ptr = list_next( &reserved_areas, ptr );
                    list_remove( &area->entry );
                    free( area );
                    continue;
                }
            }
            else
            {
                if ((char *)area->base + area->size > (char *)addr + size)
                {
                    /* range is in the middle of area -> split area in two */
                    struct reserved_area *new_area = malloc( sizeof(*new_area) );
                    if (new_area)
                    {
                        new_area->base = (char *)addr + size;
                        new_area->size = (char *)area->base + area->size - (char *)new_area->base;
                        list_add_after( ptr, &new_area->entry );
                    }
                    else size = (char *)area->base + area->size - (char *)addr;
                    area->size = (char *)addr - (char *)area->base;
                    break;
                }
                else
                {
                    /* range overlaps end of area only -> shrink area */
                    area->size = (char *)addr - (char *)area->base;
                }
            }
        }
        ptr = list_next( &reserved_areas, ptr );
    }
}

int CDECL mmap_is_in_reserved_area( void *addr, SIZE_T size )
{
    struct reserved_area *area;
    struct list *ptr;

    LIST_FOR_EACH( ptr, &reserved_areas )
    {
        area = LIST_ENTRY( ptr, struct reserved_area, entry );
        if (area->base > addr) break;
        if ((char *)area->base + area->size <= (char *)addr) continue;
        /* area must contain block completely */
        if ((char *)area->base + area->size < (char *)addr + size) return -1;
        return 1;
    }
    return 0;
}

int CDECL mmap_enum_reserved_areas( int (CDECL *enum_func)(void *base, SIZE_T size, void *arg),
                                    void *arg, int top_down )
{
    int ret = 0;
    struct list *ptr;

    if (top_down)
    {
        for (ptr = reserved_areas.prev; ptr != &reserved_areas; ptr = ptr->prev)
        {
            struct reserved_area *area = LIST_ENTRY( ptr, struct reserved_area, entry );
            if ((ret = enum_func( area->base, area->size, arg ))) break;
        }
    }
    else
    {
        for (ptr = reserved_areas.next; ptr != &reserved_areas; ptr = ptr->next)
        {
            struct reserved_area *area = LIST_ENTRY( ptr, struct reserved_area, entry );
            if ((ret = enum_func( area->base, area->size, arg ))) break;
        }
    }
    return ret;
}

void virtual_init(void)
{
    const struct preload_info **preload_info = dlsym( RTLD_DEFAULT, "wine_main_preload_info" );
    int i;

    if (preload_info && *preload_info)
        for (i = 0; (*preload_info)[i].size; i++)
            mmap_add_reserved_area( (*preload_info)[i].addr, (*preload_info)[i].size );

    mmap_init( preload_info ? *preload_info : NULL );
}