// Copyright (C) 2001-2004 by Digital Mars, www.digitalmars.com
// All Rights Reserved
// Written by Walter Bright

import std.c.linux.linuxextern;
import std.c.linux.linux;

/+
extern (C)
{
    // from <sys/mman.h>
    void* mmap(void* addr, uint len, int prot, int flags, int fd, uint offset);
    int munmap(void* addr, uint len);
    const void* MAP_FAILED = cast(void*)-1;

    // from <bits/mman.h>
    enum { PROT_NONE = 0, PROT_READ = 1, PROT_WRITE = 2, PROT_EXEC = 4 }
    enum { MAP_SHARED = 1, MAP_PRIVATE = 2, MAP_TYPE = 0x0F,
	   MAP_FIXED = 0x10, MAP_FILE = 0, MAP_ANON = 0x20 }
}
+/

/***********************************
 * Map memory.
 */

void *os_mem_map(uint nbytes)
{   void *p;

    //errno = 0;
    p = mmap(null, nbytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
    return (p == MAP_FAILED) ? null : p;
}

/***********************************
 * Commit memory.
 * Returns:
 *	0	success
 *	!=0	failure
 */

int os_mem_commit(void *base, uint offset, uint nbytes)
{
    return 0;
}


/***********************************
 * Decommit memory.
 * Returns:
 *	0	success
 *	!=0	failure
 */

int os_mem_decommit(void *base, uint offset, uint nbytes)
{
    return 0;
}

/***********************************
 * Unmap memory allocated with os_mem_map().
 * Returns:
 *	0	success
 *	!=0	failure
 */

int os_mem_unmap(void *base, uint nbytes)
{
    return munmap(base, nbytes);
}


/**********************************************
 * Determine "bottom" of stack (actually the top on x86 systems).
 */

void *os_query_stackBottom()
{
    version (none)
    {	// See discussion: http://autopackage.org/forums/viewtopic.php?t=22
	static void** libc_stack_end;

	if (libc_stack_end == libc_stack_end.init)
	{
	    void* handle = dlopen(null, RTLD_NOW);
	    libc_stack_end = cast(void **)dlsym(handle, "__libc_stack_end");
	    dlclose(handle);
	}
	return *libc_stack_end;
    }
    else
    {	// This doesn't resolve on all versions of Linux
	return __libc_stack_end;
    }
}


/**********************************************
 * Determine base address and size of static data segment.
 */

void os_query_staticdataseg(void **base, uint *nbytes)
{
    *base = cast(void *)&__data_start;
    *nbytes = cast(byte *)&_end - cast(byte *)&__data_start;
}