300 lines
9.6 KiB
C
300 lines
9.6 KiB
C
/****************************************************************************
|
|
* fs/mmap/fs_mmap.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/ioctl.h>
|
|
#include <stdint.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/kmalloc.h>
|
|
|
|
#include "inode/inode.h"
|
|
#include "fs_rammap.h"
|
|
#include "fs_anonmap.h"
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: file_mmap_
|
|
****************************************************************************/
|
|
|
|
static int file_mmap_(FAR struct file *filep, FAR void *start,
|
|
size_t length, int prot, int flags,
|
|
off_t offset, bool kernel, FAR void **mapped)
|
|
{
|
|
int ret = -ENOTTY;
|
|
|
|
/* Pass the information about the mapping in mm_map_entry_s structure.
|
|
* The driver may alter the structure, and if it supports unmap, it
|
|
* will also add it to the kernel maintained list of mappings.
|
|
*/
|
|
|
|
struct mm_map_entry_s entry =
|
|
{
|
|
NULL, /* sq_entry_t */
|
|
start,
|
|
length,
|
|
offset,
|
|
prot,
|
|
flags,
|
|
{ NULL }, /* priv.p */
|
|
NULL /* munmap */
|
|
};
|
|
|
|
/* Since only a tiny subset of mmap() functionality, we have to verify many
|
|
* things.
|
|
*/
|
|
|
|
/* A flags with MAP_PRIVATE and MAP_SHARED is invalid. */
|
|
|
|
if ((flags & MAP_PRIVATE) && (flags & MAP_SHARED))
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Fixed mappings and protections are not currently supported. These
|
|
* options could be supported in the KERNEL build with an MMU, but that
|
|
* logic is not in place.
|
|
*/
|
|
|
|
if ((flags & (MAP_FIXED | MAP_DENYWRITE)) != 0)
|
|
{
|
|
ferr("ERROR: Unsupported options, prot=%x flags=%04x\n", prot, flags);
|
|
return -ENOSYS;
|
|
}
|
|
|
|
/* A length of 0 is invalid. */
|
|
|
|
if (length == 0)
|
|
{
|
|
ferr("ERROR: Invalid length, length=%zu\n", length);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Check if we are just be asked to allocate memory, i.e., MAP_ANONYMOUS
|
|
* set meaning that the memory is not backed up from a file. The file
|
|
* descriptor should be -1 (or refer to opened /dev/zero) in this case.
|
|
* The file descriptor is ignored in either case.
|
|
*/
|
|
|
|
if ((flags & MAP_ANONYMOUS) != 0)
|
|
{
|
|
ret = map_anonymous(&entry, kernel);
|
|
|
|
/* According to the mmap(2) specification, anonymous pages should be
|
|
* initialized to zero unless the MAP_UNINITIALIZED is specified.
|
|
*/
|
|
|
|
if ((ret == OK) && (flags & MAP_UNINITIALIZED) == 0)
|
|
{
|
|
DEBUGASSERT(entry.vaddr != NULL);
|
|
memset(entry.vaddr, 0, entry.length);
|
|
}
|
|
|
|
goto out;
|
|
}
|
|
|
|
if (filep == NULL)
|
|
{
|
|
return -EBADF;
|
|
}
|
|
|
|
if ((flags & MAP_SHARED) &&
|
|
(filep->f_oflags & O_WROK) == 0 && prot == PROT_WRITE)
|
|
{
|
|
ferr("ERROR: Unsupported options for read-only file descriptor,"
|
|
"prot=%x flags=%04x\n", prot, flags);
|
|
return -EACCES;
|
|
}
|
|
|
|
if ((filep->f_oflags & O_RDOK) == 0)
|
|
{
|
|
ferr("ERROR: File descriptor does not have read permission\n");
|
|
return -EACCES;
|
|
}
|
|
|
|
/* Call driver's mmap to get the base address of the file in 'mapped'
|
|
* in memory.
|
|
*/
|
|
|
|
if (filep->f_inode &&
|
|
filep->f_inode->u.i_ops->mmap != NULL)
|
|
{
|
|
ret = filep->f_inode->u.i_ops->mmap(filep, &entry);
|
|
}
|
|
|
|
if (ret == -ENOTTY)
|
|
{
|
|
/* Caller request the private mapping. Or not directly mappable,
|
|
* probably because the underlying media doesn't support random access.
|
|
*/
|
|
|
|
/* Allocate memory and copy the file into memory. We would, of course,
|
|
* do much better in the KERNEL build using the MMU.
|
|
*/
|
|
|
|
ret = rammap(filep, &entry, kernel);
|
|
}
|
|
|
|
/* Return */
|
|
|
|
out:
|
|
if (ret >= OK)
|
|
{
|
|
*mapped = entry.vaddr;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: file_mmap
|
|
*
|
|
* Description:
|
|
* Equivalent to the standard mmap() function except that is accepts
|
|
* a struct file instance instead of a file descriptor and it does not set
|
|
* the errno variable.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int file_mmap(FAR struct file *filep, FAR void *start, size_t length,
|
|
int prot, int flags, off_t offset, FAR void **mapped)
|
|
{
|
|
return file_mmap_(filep, start, length,
|
|
prot, flags, offset, true, mapped);
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: mmap
|
|
*
|
|
* Description:
|
|
* NuttX operates in a flat open address space. Therefore, it generally
|
|
* does not require mmap() functionality. There are two exceptions:
|
|
*
|
|
* 1. mmap() is the API that is used to support direct access to random
|
|
* access media under the following very restrictive conditions:
|
|
*
|
|
* a. The filesystem implements the mmap file operation. Any file
|
|
* system that maps files contiguously on the media should support
|
|
* this ioctl. (vs. file system that scatter files over the media
|
|
* in non-contiguous sectors). As of this writing, ROMFS is the
|
|
* only file system that meets this requirement.
|
|
* b. The underlying block driver supports the BIOC_XIPBASE ioctl
|
|
* command that maps the underlying media to a randomly accessible
|
|
* address. At present, only the RAM/ROM disk driver does this.
|
|
*
|
|
* 2. If CONFIG_FS_RAMMAP is defined in the configuration, then mmap() will
|
|
* support simulation of memory mapped files by copying files whole
|
|
* into RAM.
|
|
*
|
|
* Input Parameters:
|
|
* start A hint at where to map the memory -- ignored. The address
|
|
* of the underlying media is fixed and cannot be re-mapped without
|
|
* MMU support.
|
|
* length The length of the mapping. For exception #1 above, this length
|
|
* ignored: The entire underlying media is always accessible.
|
|
* prot See the PROT_* definitions in sys/mman.h.
|
|
* PROT_NONE - Will cause an error
|
|
* PROT_READ - PROT_WRITE and PROT_EXEC also assumed
|
|
* PROT_WRITE - PROT_READ and PROT_EXEC also assumed
|
|
* PROT_EXEC - PROT_READ and PROT_WRITE also assumed
|
|
* flags See the MAP_* definitions in sys/mman.h.
|
|
* MAP_SHARED - MAP_PRIVATE or MAP_SHARED required
|
|
* MAP_PRIVATE - MAP_PRIVATE or MAP_SHARED required
|
|
* MAP_FIXED - Will cause an error
|
|
* MAP_FILE - Ignored
|
|
* MAP_ANONYMOUS - Optional
|
|
* MAP_ANON - Will cause an error
|
|
* MAP_GROWSDOWN - Ignored
|
|
* MAP_DENYWRITE - Will cause an error
|
|
* MAP_EXECUTABLE - Ignored
|
|
* MAP_LOCKED - Ignored
|
|
* MAP_NORESERVE - Ignored
|
|
* MAP_POPULATE - Ignored
|
|
* MAP_NONBLOCK - Ignored
|
|
* fd file descriptor of the backing file.
|
|
* offset The offset into the file to map
|
|
*
|
|
* Returned Value:
|
|
* On success, mmap() returns a pointer to the mapped area. On error, the
|
|
* value MAP_FAILED is returned, and errno is set appropriately.
|
|
*
|
|
* EACCES
|
|
* The fd argument is not open for read, regardless of the
|
|
* protection specified, or fd is not open for write and PROT_WRITE
|
|
* was specified for a MAP_SHARED type mapping.
|
|
* ENOSYS
|
|
* Returned if any of the unsupported mmap() features are attempted
|
|
* EBADF
|
|
* 'fd' is not a valid file descriptor.
|
|
* EINVAL
|
|
* Length is 0. flags contained neither MAP_PRIVATE or MAP_SHARED, or
|
|
* contained both of these values.
|
|
* ENODEV
|
|
* The underlying filesystem of the specified file does not support
|
|
* memory mapping.
|
|
* ENOMEM
|
|
* Insufficient memory is available to map the file.
|
|
*
|
|
****************************************************************************/
|
|
|
|
FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
|
|
int fd, off_t offset)
|
|
{
|
|
FAR struct file *filep = NULL;
|
|
FAR void *mapped = NULL;
|
|
int ret;
|
|
|
|
if (fd != -1 && fs_getfilep(fd, &filep) < 0)
|
|
{
|
|
ferr("ERROR: fd:%d referred file whose type is not supported\n", fd);
|
|
ret = -ENODEV;
|
|
goto errout;
|
|
}
|
|
|
|
ret = file_mmap_(filep, start, length,
|
|
prot, flags, offset, false, &mapped);
|
|
if (ret < 0)
|
|
{
|
|
goto errout;
|
|
}
|
|
|
|
return mapped;
|
|
|
|
errout:
|
|
set_errno(-ret);
|
|
return MAP_FAILED;
|
|
}
|