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nuttx/fs/mount/fs_mount.c
Gregory Nutt 6e9039bb08 Squashed commit of the following: 
fs/userfs:  This completes coding of the UserFS client and of the UserFS feature in general.  This feature is being merged to main now because I believe it is innocuous.  It is, however, untesed.  The next step will be to develop a test case to verify the feature.
    fs/userfs:  Completes the request logic for the UserFS client.  Still need the logic that receives the responses.
    fs/userfs:  Completes coding for most of the server side of the user filesystem logic.
    fs/userfs:  Big design changes, simplications. Use Unix domain local sockets instead of message queues.  Easier to transfer big data in local sockets than message queues.  Remove character drvier 'factory' it is not necessary.
    fs/userfs:  Minor reparitioning; volume private info does not need to be held on the OS client side.
    libc/userfs:  Add some of the server side logic.
    fs/userfs:  Add some UserFS initialization logic.
    fs/userfs:  Add frame work for the UserFS proxy.  Remove all references to a block driver.  There is no block dricer... what was I thinking?
    fs/userfs: Add some initialization of the character driver, 'factory' device.
    fs/userfs:  Rename from fusefs to userfs to that we don't stomp on someone else's cool name.
    Add a header file describing the fusefs interface.
2017-10-30 18:07:42 -06:00

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/****************************************************************************
* fs/mount/fs_mount.c
*
* Copyright (C) 2007-2009, 2011-2013, 2015, 2017 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 <stdbool.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include "inode/inode.h"
#include "driver/driver.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) || \
defined(CONFIG_FS_TMPFS) || defined(CONFIG_FS_USERFS)
# define NONBDFS_SUPPORT
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct fsmap_t
{
FAR const char *fs_filesystemtype;
FAR const struct mountpt_operations *fs_mops;
};
/****************************************************************************
* Private Data
****************************************************************************/
#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_FS_TMPFS
extern const struct mountpt_operations tmpfs_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
#ifdef CONFIG_FS_USERFS
extern const struct mountpt_operations userfs_operations;
#endif
#ifdef CONFIG_FS_HOSTFS
extern const struct mountpt_operations hostfs_operations;
#endif
static const struct fsmap_t g_nonbdfsmap[] =
{
#ifdef CONFIG_FS_NXFFS
{ "nxffs", &nxffs_operations },
#endif
#ifdef CONFIG_FS_TMPFS
{ "tmpfs", &tmpfs_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
#ifdef CONFIG_FS_USERFS
{ "userfs", &userfs_operations },
#endif
#ifdef CONFIG_FS_HOSTFS
{ "hostfs", &hostfs_operations },
#endif
{ NULL, NULL },
};
#endif /* NONBDFS_SUPPORT */
/****************************************************************************
* 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;
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
struct inode_search_s desc;
#endif
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)
{
ferr("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 */
{
ferr("ERROR: Failed to find file system %s\n", filesystemtype);
errcode = ENODEV;
goto errout;
}
inode_semtake();
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
/* Check if the inode already exists */
SETUP_SEARCH(&desc, target, false);
ret = inode_find(&desc);
if (ret >= 0)
{
/* Successfully found. The reference count on the inode has been
* incremented.
*/
mountpt_inode = desc.node;
DEBUGASSERT(mountpt_inode != NULL);
/* But is it a directory node (i.e., not a driver or other special
* node)?
*/
if (INODE_IS_SPECIAL(mountpt_inode))
{
ferr("ERROR: target %s exists and is a special node\n", target);
errcode = -ENOTDIR;
inode_release(mountpt_inode);
goto errout_with_semaphore;
}
}
else
#endif
/* Insert a dummy node -- we need to hold the inode semaphore
* to do this because we will have a momentarily bad structure.
* NOTE that the new inode will be created with an initial reference
* count of zero.
*/
{
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
*/
ferr("ERROR: Failed to reserve inode for target %s\n", target);
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 ??? */
ferr("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.
*/
ferr("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 umount2() is called.
*/
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
inode_release(blkdrvr_inode);
}
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
RELEASE_SEARCH(&desc);
#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);
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
RELEASE_SEARCH(&desc);
#endif
goto errout;
errout_with_semaphore:
inode_semgive();
#ifdef BDFS_SUPPORT
#ifdef NONBDFS_SUPPORT
if (blkdrvr_inode)
#endif
{
inode_release(blkdrvr_inode);
}
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
RELEASE_SEARCH(&desc);
#endif
errout:
set_errno(errcode);
return ERROR;
#else
ferr("ERROR: No filesystems enabled\n");
set_errno(ENOSYS);
return ERROR;
#endif /* BDFS_SUPPORT || NONBDFS_SUPPORT */
}
#endif /* CONFIG_FS_READABLE */
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