heap.c

来自「xenomai 很好的linux实时补丁」· C语言 代码 · 共 178 行

/*
 * Copyright (C) 2001,2002,2003,2004 Philippe Gerum <[e-mail]>.
 *
 * 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 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <native/syscall.h>
#include <native/task.h>
#include <native/heap.h>

extern int __native_muxid;

static int __map_heap_memory (RT_HEAP *heap, RT_HEAP_PLACEHOLDER *php)

{
    int err, heapfd;

    /* Open the heap device to share the heap memory with the
       in-kernel skin and bound clients. */
    heapfd = open(XNHEAP_DEV_NAME,O_RDWR);

    if (heapfd < 0)
	return -ENOENT;

    /* Bind this file instance to the shared heap. */
    err = ioctl(heapfd,0,php->opaque2);

    if (err)
	goto close_and_exit;

    /* Map the heap memory into our address space. */
    php->mapbase = (caddr_t)mmap(NULL,
				 php->mapsize,
				 PROT_READ|PROT_WRITE,
				 MAP_SHARED,
				 heapfd,
				 0L);

    if (php->mapbase != MAP_FAILED)
	/* Copy back a complete placeholder only if all is ok. */
	*heap = *php;
    else
	err = -ENOMEM;

 close_and_exit:

    close(heapfd);

    return err;
}

int rt_heap_create (RT_HEAP *heap,
		    const char *name,
		    size_t heapsize,
		    int mode)
{
    RT_HEAP_PLACEHOLDER ph;
    int err;

    err = XENOMAI_SKINCALL4(__native_muxid,
			    __native_heap_create,
			    &ph,
			    name,
			    heapsize,
			    mode|H_MAPPABLE);
    if (err)
	return err;

    err = __map_heap_memory(heap,&ph);

    if (err)
	/* If the mapping fails, make sure we don't leave a dandling
	   heap in kernel space -- remove it. */
	XENOMAI_SKINCALL1(__native_muxid,
			  __native_heap_delete,
			  &ph);
    return err;
}

int rt_heap_bind (RT_HEAP *heap,
		  const char *name,
		  RTIME timeout)
{
    RT_HEAP_PLACEHOLDER ph;
    int err;

    err = XENOMAI_SKINCALL3(__native_muxid,
			    __native_heap_bind,
			    &ph,
			    name,
			    &timeout);

    return err ?: __map_heap_memory(heap,&ph);
}

int rt_heap_unbind (RT_HEAP *heap)

{
    int err = munmap(heap->mapbase,heap->mapsize);

    heap->opaque = XN_NO_HANDLE;
    heap->mapbase = NULL;
    heap->mapsize = 0;

    return err;
}

int rt_heap_delete (RT_HEAP *heap)

{
    int err;

    err = munmap(heap->mapbase,heap->mapsize);

    if (!err)
	err = XENOMAI_SKINCALL1(__native_muxid,
				__native_heap_delete,
				heap);

    /* If the deletion fails, there is likely something fishy about
       this heap descriptor, so we'd better clean it up anyway so
       that it could not be further used. */

    heap->opaque = XN_NO_HANDLE;
    heap->mapbase = NULL;
    heap->mapsize = 0;

    return err;
}

int rt_heap_alloc (RT_HEAP *heap,
		   size_t size,
		   RTIME timeout,
		   void **bufp)
{
    return XENOMAI_SKINCALL4(__native_muxid,
			     __native_heap_alloc,
			     heap,
			     size,
			     &timeout,
			     bufp);
}

int rt_heap_free (RT_HEAP *heap,
		  void *buf)
{
    return XENOMAI_SKINCALL2(__native_muxid,
			     __native_heap_free,
			     heap,
			     buf);
}

int rt_heap_inquire (RT_HEAP *heap,
		     RT_HEAP_INFO *info)
{
    return XENOMAI_SKINCALL2(__native_muxid,
			     __native_heap_inquire,
			     heap,
			     info);
}