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nuttx/fs/fs_mount.c

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/****************************************************************************
* fs/fs_mount.c
*
* Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/mount.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include "fs_internal.h"
/* At least one filesystem must be defined, or this file will not compile.
* It may be desire-able to make filesystems dynamically registered at
* some time in the future, but at present, this file needs to know about
* every configured filesystem.
*/
#ifdef CONFIG_FS_READABLE
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* In the canonical case, a file system is bound to a block driver. However,
* some less typical cases a block driver is not required. Examples are
* pseudo file systems (like BINFS or PROCFS) and MTD file systems (like NXFFS).
*
* These file systems all require block drivers:
*/
#if defined(CONFIG_FS_FAT) || defined(CONFIG_FS_ROMFS) || \
defined(CONFIG_FS_SMARTFS)
# define BDFS_SUPPORT 1
#endif
/* These file systems do not require block drivers */
#if defined(CONFIG_FS_NXFFS) || defined(CONFIG_FS_BINFS) || \
defined(CONFIG_FS_PROCFS) || defined(CONFIG_NFS)
# define NONBDFS_SUPPORT
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct fsmap_t
{
FAR const char *fs_filesystemtype;
FAR const struct mountpt_operations *fs_mops;
};
/****************************************************************************
* Private Variables
****************************************************************************/
#ifdef BDFS_SUPPORT
#ifdef CONFIG_FS_FAT
extern const struct mountpt_operations fat_operations;
#endif
#ifdef CONFIG_FS_ROMFS
extern const struct mountpt_operations romfs_operations;
#endif
#ifdef CONFIG_FS_SMARTFS
extern const struct mountpt_operations smartfs_operations;
#endif
static const struct fsmap_t g_bdfsmap[] =
{
#ifdef CONFIG_FS_FAT
{ "vfat", &fat_operations },
#endif
#ifdef CONFIG_FS_ROMFS
{ "romfs", &romfs_operations },
#endif
#ifdef CONFIG_FS_SMARTFS
{ "smartfs", &smartfs_operations },
#endif
{ NULL, NULL },
};
#endif /* BDFS_SUPPORT*/
#ifdef NONBDFS_SUPPORT
#ifdef CONFIG_FS_NXFFS
extern const struct mountpt_operations nxffs_operations;
#endif
#ifdef CONFIG_NFS
extern const struct mountpt_operations nfs_operations;
#endif
#ifdef CONFIG_FS_BINFS
extern const struct mountpt_operations binfs_operations;
#endif
#ifdef CONFIG_FS_PROCFS
extern const struct mountpt_operations procfs_operations;
#endif
static const struct fsmap_t g_nonbdfsmap[] =
{
#ifdef CONFIG_FS_NXFFS
{ "nxffs", &nxffs_operations },
#endif
#ifdef CONFIG_NFS
{ "nfs", &nfs_operations },
#endif
#ifdef CONFIG_FS_BINFS
{ "binfs", &binfs_operations },
#endif
#ifdef CONFIG_FS_PROCFS
{ "procfs", &procfs_operations },
#endif
{ NULL, NULL },
};
#endif /* NONBDFS_SUPPORT */
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mount_findfs
*
* Description:
* find the specified filesystem
*
****************************************************************************/
#if defined(BDFS_SUPPORT) || defined(NONBDFS_SUPPORT)
static FAR const struct mountpt_operations *
mount_findfs(FAR const struct fsmap_t *fstab, FAR const char *filesystemtype)
{
FAR const struct fsmap_t *fsmap;
for (fsmap = fstab; fsmap->fs_filesystemtype; fsmap++)
{
if (strcmp(filesystemtype, fsmap->fs_filesystemtype) == 0)
{
return fsmap->fs_mops;
}
}
return NULL;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mount
*
* Description:
* mount() attaches the filesystem specified by the 'source' block device
* name into the root file system at the path specified by 'target.'
*
* Return:
* Zero is returned on success; -1 is returned on an error and errno is
* set appropriately:
*
* EACCES A component of a path was not searchable or mounting a read-only
* filesystem was attempted without giving the MS_RDONLY flag.
* EBUSY 'source' is already mounted.
* EFAULT One of the pointer arguments points outside the user address
* space.
* EINVAL 'source' had an invalid superblock.
* ENODEV 'filesystemtype' not configured
* ENOENT A pathname was empty or had a nonexistent component.
* ENOMEM Could not allocate a memory to copy filenames or data into.
* ENOTBLK 'source' is not a block device
*
****************************************************************************/
int mount(FAR const char *source, FAR const char *target,
FAR const char *filesystemtype, unsigned long mountflags,
FAR const void *data)
{
#if defined(BDFS_SUPPORT) || defined(NONBDFS_SUPPORT)
#ifdef BDFS_SUPPORT
FAR struct inode *blkdrvr_inode = NULL;
#endif
FAR struct inode *mountpt_inode;
FAR const struct mountpt_operations *mops;
void *fshandle;
int errcode;
int ret;
/* Verify required pointer arguments */
DEBUGASSERT(target && filesystemtype);
/* Find the specified filesystem. Try the block driver file systems first */
#ifdef BDFS_SUPPORT
if (source && (mops = mount_findfs(g_bdfsmap, filesystemtype)) != NULL)
{
/* Make sure that a block driver argument was provided */
DEBUGASSERT(source);
/* Find the block driver */
ret = find_blockdriver(source, mountflags, &blkdrvr_inode);
if (ret < 0)
{
fdbg("ERROR: Failed to find block driver %s\n", source);
errcode = -ret;
goto errout;
}
}
else
#endif /* BDFS_SUPPORT */
#ifdef NONBDFS_SUPPORT
if ((mops = mount_findfs(g_nonbdfsmap, filesystemtype)) != NULL)
{
}
else
#endif /* NONBDFS_SUPPORT */
{
fdbg("ERROR: Failed to find file system %s\n", filesystemtype);
errcode = ENODEV;
goto errout;
}
/* Insert a dummy node -- we need to hold the inode semaphore
* to do this because we will have a momentarily bad structure.
*/
inode_semtake();
ret = inode_reserve(target, &mountpt_inode);
if (ret < 0)
{
/* inode_reserve can fail for a couple of reasons, but the most likely
* one is that the inode already exists. inode_reserve may return:
*
* -EINVAL - 'path' is invalid for this operation
* -EEXIST - An inode already exists at 'path'
* -ENOMEM - Failed to allocate in-memory resources for the operation
*/
fdbg("ERROR: Failed to reserve inode\n");
errcode = -ret;
goto errout_with_semaphore;
}
/* Bind the block driver to an instance of the file system. The file
* system returns a reference to some opaque, fs-dependent structure
* that encapsulates this binding.
*/
if (!mops->bind)
{
/* The filesystem does not support the bind operation ??? */
fdbg("ERROR: Filesystem does not support bind\n");
errcode = EINVAL;
goto errout_with_mountpt;
}
/* Increment reference count for the reference we pass to the file system */
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
blkdrvr_inode->i_crefs++;
}
#endif
/* On failure, the bind method returns -errorcode */
#ifdef BDFS_SUPPORT
ret = mops->bind(blkdrvr_inode, data, &fshandle);
#else
ret = mops->bind(NULL, data, &fshandle);
#endif
if (ret != 0)
{
/* The inode is unhappy with the blkdrvr for some reason. Back out
* the count for the reference we failed to pass and exit with an
* error.
*/
fdbg("ERROR: Bind method failed: %d\n", ret);
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
blkdrvr_inode->i_crefs--;
}
#endif
errcode = -ret;
goto errout_with_mountpt;
}
/* We have it, now populate it with driver specific information. */
INODE_SET_MOUNTPT(mountpt_inode);
mountpt_inode->u.i_mops = mops;
#ifdef CONFIG_FILE_MODE
mountpt_inode->i_mode = mode;
#endif
mountpt_inode->i_private = fshandle;
inode_semgive();
/* We can release our reference to the blkdrver_inode, if the filesystem
* wants to retain the blockdriver inode (which it should), then it must
* have called inode_addref(). There is one reference on mountpt_inode
* that will persist until umount() is called.
*/
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
inode_release(blkdrvr_inode);
}
#endif
return OK;
/* A lot of goto's! But they make the error handling much simpler */
errout_with_mountpt:
mountpt_inode->i_crefs = 0;
inode_remove(target);
inode_semgive();
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
inode_release(blkdrvr_inode);
}
#endif
inode_release(mountpt_inode);
goto errout;
errout_with_semaphore:
inode_semgive();
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
inode_release(blkdrvr_inode);
}
#endif
errout:
set_errno(errcode);
return ERROR;
#else
fdbg("ERROR: No filesystems enabled\n");
set_errno(ENOSYS);
return ERROR;
#endif /* BDFS_SUPPORT || NONBDFS_SUPPORT */
}
#endif /* CONFIG_FS_READABLE */
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