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incubator-nuttx/fs/mount/fs_mount.c

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/****************************************************************************
* fs/mount/fs_mount.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/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"
/****************************************************************************
* 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) || defined(CONFIG_FS_LITTLEFS)
# define BDFS_SUPPORT 1
#endif
/* These file systems require MTD drivers */
#if (defined(CONFIG_FS_SPIFFS) || defined(CONFIG_FS_LITTLEFS)) && \
defined(CONFIG_MTD)
# define MDFS_SUPPORT 1
#endif
/* These file systems do not require block or MTD 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) || \
defined(CONFIG_FS_CROMFS) || defined(CONFIG_FS_UNIONFS) || \
defined(CONFIG_FS_HOSTFS)
# define NODFS_SUPPORT
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct fsmap_t
{
FAR const char *fs_filesystemtype;
FAR const struct mountpt_operations *fs_mops;
};
/****************************************************************************
* Private Data
****************************************************************************/
#ifdef BDFS_SUPPORT
/* File systems that require block drivers */
#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
#ifdef CONFIG_FS_LITTLEFS
extern const struct mountpt_operations littlefs_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
#ifdef CONFIG_FS_LITTLEFS
{ "littlefs", &littlefs_operations },
#endif
{ NULL, NULL },
};
#endif /* BDFS_SUPPORT */
#ifdef MDFS_SUPPORT
/* File systems that require MTD drivers */
#ifdef CONFIG_FS_ROMFS
extern const struct mountpt_operations romfs_operations;
#endif
#ifdef CONFIG_FS_SPIFFS
extern const struct mountpt_operations spiffs_operations;
#endif
#ifdef CONFIG_FS_LITTLEFS
extern const struct mountpt_operations littlefs_operations;
#endif
static const struct fsmap_t g_mdfsmap[] =
{
#ifdef CONFIG_FS_ROMFS
{ "romfs", &romfs_operations },
#endif
#ifdef CONFIG_FS_SPIFFS
{ "spiffs", &spiffs_operations },
#endif
#ifdef CONFIG_FS_LITTLEFS
{ "littlefs", &littlefs_operations },
#endif
{ NULL, NULL },
};
#endif /* MDFS_SUPPORT */
#ifdef NODFS_SUPPORT
/* File systems that require neither block nor MTD drivers */
#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
#ifdef CONFIG_FS_CROMFS
extern const struct mountpt_operations cromfs_operations;
#endif
#ifdef CONFIG_FS_UNIONFS
extern const struct mountpt_operations unionfs_operations;
#endif
#ifdef CONFIG_FS_RPMSGFS
extern const struct mountpt_operations rpmsgfs_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
#ifdef CONFIG_FS_CROMFS
{ "cromfs", &cromfs_operations },
#endif
#ifdef CONFIG_FS_UNIONFS
{ "unionfs", &unionfs_operations },
#endif
#ifdef CONFIG_FS_RPMSGFS
{ "rpmsgfs", &rpmsgfs_operations },
#endif
{ NULL, NULL },
};
#endif /* NODFS_SUPPORT */
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mount_findfs
*
* Description:
* find the specified filesystem
*
****************************************************************************/
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT) || defined(NODFS_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: nx_mount
*
* Description:
* nx_mount() is similar to the standard 'mount' interface except that is
* not a cancellation point and it does not modify the errno variable.
*
* nx_mount() is an internal NuttX interface and should not be called from
* applications.
*
* Returned Value:
* Zero is returned on success; a negated value is returned on any failure.
*
****************************************************************************/
int nx_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(MDFS_SUPPORT) || defined(NODFS_SUPPORT)
FAR struct inode *drvr_inode = NULL;
FAR struct inode *mountpt_inode;
FAR const struct mountpt_operations *mops = NULL;
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
struct inode_search_s desc;
#endif
void *fshandle;
int ret;
/* Verify required pointer arguments */
DEBUGASSERT(target && filesystemtype);
/* Find the specified filesystem. Try the block driver filesystems first */
if (source != NULL &&
find_blockdriver(source, mountflags, &drvr_inode) >= 0)
{
/* Find the block based file system */
#ifdef BDFS_SUPPORT
mops = mount_findfs(g_bdfsmap, filesystemtype);
#endif /* BDFS_SUPPORT */
if (mops == NULL)
{
ferr("ERROR: Failed to find block based file system %s\n",
filesystemtype);
ret = -ENODEV;
goto errout_with_inode;
}
}
else if (source != NULL &&
(ret = find_mtddriver(source, &drvr_inode)) >= 0)
{
/* Find the MTD based file system */
#ifdef MDFS_SUPPORT
mops = mount_findfs(g_mdfsmap, filesystemtype);
#endif /* MDFS_SUPPORT */
if (mops == NULL)
{
ferr("ERROR: Failed to find MTD based file system %s\n",
filesystemtype);
ret = -ENODEV;
goto errout_with_inode;
}
}
else
#ifdef NODFS_SUPPORT
if ((mops = mount_findfs(g_nonbdfsmap, filesystemtype)) != NULL)
{
}
else
#endif /* NODFS_SUPPORT */
{
ferr("ERROR: Failed to find block driver %s\n", source);
ret = -ENOTBLK;
goto errout;
}
ret = inode_lock();
if (ret < 0)
{
goto errout_with_inode;
}
#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_PSEUDODIR(mountpt_inode))
{
ferr("ERROR: target %s exists and is a special node\n", target);
ret = -ENOTDIR;
inode_release(mountpt_inode);
goto errout_with_lock;
}
}
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, 0777, &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);
goto errout_with_lock;
}
}
/* 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 == NULL)
{
/* The filesystem does not support the bind operation ??? */
ferr("ERROR: Filesystem does not support bind\n");
ret = -EINVAL;
goto errout_with_mountpt;
}
/* Increment reference count for the reference we pass to the file system */
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT)
#ifdef NODFS_SUPPORT
if (drvr_inode != NULL)
#endif
{
drvr_inode->i_crefs++;
}
#endif
/* On failure, the bind method returns -errorcode */
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT)
ret = mops->bind(drvr_inode, data, &fshandle);
#else
ret = mops->bind(NULL, data, &fshandle);
#endif
if (ret < 0)
{
/* The inode is unhappy with the driver 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);
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT)
#ifdef NODFS_SUPPORT
if (drvr_inode != NULL)
#endif
{
drvr_inode->i_crefs--;
}
#endif
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;
mountpt_inode->i_private = fshandle;
inode_unlock();
/* 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.
*/
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT)
#ifdef NODFS_SUPPORT
if (drvr_inode != NULL)
#endif
{
inode_release(drvr_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:
inode_release(mountpt_inode);
inode_remove(target);
errout_with_lock:
inode_unlock();
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
RELEASE_SEARCH(&desc);
#endif
errout_with_inode:
#if defined(BDFS_SUPPORT) || defined(MDFS_SUPPORT)
if (drvr_inode != NULL)
{
inode_release(drvr_inode);
}
#endif
errout:
return ret;
#else
ferr("ERROR: No filesystems enabled\n");
return -ENOSYS;
#endif /* BDFS_SUPPORT || MDFS_SUPPORT || NODFS_SUPPORT */
}
/****************************************************************************
* 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.'
*
* Returned Value:
* 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)
{
int ret;
ret = nx_mount(source, target, filesystemtype, mountflags, data);
if (ret < 0)
{
set_errno(-ret);
ret = ERROR;
}
return ret;
}
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