forked from Archive/PX4-Autopilot
503 lines
15 KiB
C
503 lines
15 KiB
C
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/****************************************************************************
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* fs/nxffs/nxffs_inode.c
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* References: Linux/Documentation/filesystems/romfs.txt
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <string.h>
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#include <crc32.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/mtd.h>
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#include "nxffs.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/****************************************************************************
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* Public Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxffs_rdentry
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*
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* Description:
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* Read the inode entry at this offset. Called only from nxffs_nextentry().
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*
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* Input Parameters:
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* volume - Describes the current volume.
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* offset - The byte offset from the beginning of FLASH where the inode
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* header is expected.
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* entry - A memory location to return the expanded inode header
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* information.
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*
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* Returned Value:
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* Zero on success. Otherwise, a negated errno value is returned
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* indicating the nature of the failure.
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*
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* On return, the
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*
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****************************************************************************/
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static int nxffs_rdentry(FAR struct nxffs_volume_s *volume, off_t offset,
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FAR struct nxffs_entry_s *entry)
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{
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struct nxffs_inode_s inode;
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uint32_t ecrc;
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uint32_t crc;
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uint8_t state;
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int namlen;
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int ret;
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DEBUGASSERT(volume && entry);
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memset(entry, 0, sizeof(struct nxffs_entry_s));
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/* Read the header at the FLASH offset */
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nxffs_ioseek(volume, offset);
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memcpy(&inode, &volume->cache[volume->iooffset], SIZEOF_NXFFS_INODE_HDR);
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/* Check if the file state is recognized. */
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state = inode.state;
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if (state != INODE_STATE_FILE && state != INODE_STATE_DELETED)
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{
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/* This can't be a valid inode.. don't bother with the rest */
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ret = -ENOENT;
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goto errout_no_offset;
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}
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/* Copy the packed header into the user-friendly buffer */
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entry->hoffset = offset;
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entry->noffset = nxffs_rdle32(inode.noffs);
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entry->doffset = nxffs_rdle32(inode.doffs);
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entry->utc = nxffs_rdle32(inode.utc);
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entry->datlen = nxffs_rdle32(inode.datlen);
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/* Modify the packed header and perform the (partial) CRC calculation */
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ecrc = nxffs_rdle32(inode.crc);
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inode.state = CONFIG_NXFFS_ERASEDSTATE;
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memset(inode.crc, 0, 4);
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crc = crc32((FAR const uint8_t *)&inode, SIZEOF_NXFFS_INODE_HDR);
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/* Allocate memory to hold the variable-length file name */
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namlen = inode.namlen;
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entry->name = (FAR char *)kmalloc(namlen + 1);
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if (!entry->name)
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{
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fdbg("Failed to allocate name, namlen: %d\n", namlen);
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ret = -ENOMEM;
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goto errout_no_offset;
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}
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/* Seek to the expected location of the name in FLASH */
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nxffs_ioseek(volume, entry->noffset);
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/* Make sure that the block is in memory (the name may not be in the
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* same block as the inode header.
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*/
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ret = nxffs_rdcache(volume, volume->ioblock);
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if (ret < 0)
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{
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fdbg("nxffsx_rdcache failed: %d\n", -ret);
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goto errout_with_name;
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}
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/* Read the file name from the expected offset in FLASH */
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memcpy(entry->name, &volume->cache[volume->iooffset], namlen);
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entry->name[namlen] = '\0';
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/* Finish the CRC calculation and verify the entry */
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crc = crc32part((FAR const uint8_t *)entry->name, namlen, crc);
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if (crc != ecrc)
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{
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fdbg("CRC entry: %08x CRC calculated: %08x\n", ecrc, crc);
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ret = -EIO;
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goto errout_with_name;
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}
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/* We have a good inode header.. but it still could a deleted file.
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* Check the file state.
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*/
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if (state != INODE_STATE_FILE)
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{
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/* It is a deleted file. But still, the data offset and the
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* start size are good so we can use this information to advance
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* further in FLASH memory and reduce the search time.
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*/
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offset = nxffs_inodeend(volume, entry);
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nxffs_freeentry(entry);
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ret = -ENOENT;
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goto errout;
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}
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/* Everything is good.. leave the offset pointing to the valid inode
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* header.
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*/
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return OK;
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/* On errors where we are suspicious of the validity of the inode header,
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* we need to increment the file position to just after the "good" magic
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* word.
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*/
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errout_with_name:
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nxffs_freeentry(entry);
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errout_no_offset:
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offset += NXFFS_MAGICSIZE;
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errout:
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nxffs_ioseek(volume, offset);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxffs_freeentry
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*
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* Description:
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* The inode values returned by nxffs_nextentry() include allocated memory
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* (specifically, the file name string). This function should be called
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* to dispose of that memory when the inode entry is no longer needed.
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*
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* Note that the nxffs_entry_s containing structure is not freed. The
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* caller may call kfree upon return of this function if necessary to
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* free the entry container.
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*
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* Input parameters:
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* entry - The entry to be freed.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void nxffs_freeentry(FAR struct nxffs_entry_s *entry)
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{
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if (entry->name)
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{
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kfree(entry->name);
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entry->name = NULL;
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}
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}
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/****************************************************************************
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* Name: nxffs_nextentry
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*
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* Description:
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* Search for the next valid inode starting at the provided FLASH offset.
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*
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* Input Parameters:
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* volume - Describes the NXFFS volume.
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* offset - The FLASH memory offset to begin searching.
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* entry - A pointer to memory provided by the caller in which to return
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* the inode description.
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*
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* Returned Value:
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* Zero is returned on success. Otherwise, a negated errno is returned
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* that indicates the nature of the failure.
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*
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****************************************************************************/
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int nxffs_nextentry(FAR struct nxffs_volume_s *volume, off_t offset,
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FAR struct nxffs_entry_s *entry)
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{
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int nmagic;
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int ch;
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int nerased;
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int ret;
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/* Seek to the first FLASH offset provided by the caller. */
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nxffs_ioseek(volume, offset);
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/* Then begin searching */
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nerased = 0;
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nmagic = 0;
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for (;;)
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{
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/* Read the next character */
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ch = nxffs_getc(volume, SIZEOF_NXFFS_INODE_HDR - nmagic);
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if (ch < 0)
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{
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fvdbg("nxffs_getc failed: %d\n", -ch);
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return ch;
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}
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/* Check for another erased byte */
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else if (ch == CONFIG_NXFFS_ERASEDSTATE)
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{
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/* If we have encountered NXFFS_NERASED number of consecutive
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* erased bytes, then presume we have reached the end of valid
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* data.
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*/
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if (++nerased >= NXFFS_NERASED)
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{
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fvdbg("No entry found\n");
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return -ENOENT;
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}
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}
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else
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{
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nerased = 0;
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/* Check for the magic sequence indicating the start of an NXFFS
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* inode. There is the possibility of this magic sequnce occurring
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* in FLASH data. However, the header CRC should distinguish
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* between real NXFFS inode headers and such false alarms.
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*/
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if (ch != g_inodemagic[nmagic])
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{
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/* Ooops... this is the not the right character for the magic
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* Sequence. Check if we need to restart or to cancel the sequence:
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*/
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if (ch == g_inodemagic[0])
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{
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nmagic = 1;
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}
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else
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{
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nmagic = 0;
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}
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}
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else if (nmagic < NXFFS_MAGICSIZE - 1)
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{
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/* We have one more character in the magic sequence */
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nmagic++;
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}
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/* We have found the magic sequence in the FLASH data that may
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* indicate the beginning of an NXFFS inode.
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*/
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else
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{
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/* The the FLASH offset where we found the matching magic number */
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offset = nxffs_iotell(volume) - NXFFS_MAGICSIZE;
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/* Try to extract the inode header from that position */
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ret = nxffs_rdentry(volume, offset, entry);
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if (ret == OK)
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{
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fvdbg("Found a valid fileheader, offset: %d\n", offset);
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return OK;
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}
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/* False alarm.. keep looking */
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nmagic = 0;
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}
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}
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}
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/* We won't get here, but to keep some compilers happy: */
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return -ENOENT;
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}
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/****************************************************************************
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* Name: nxffs_findinode
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*
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* Description:
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* Search for an inode with the provided name starting with the first
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* valid inode and proceeding to the end FLASH or until the matching
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* inode is found.
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*
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* Input Parameters:
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* volume - Describes the NXFFS volume
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* name - The name of the inode to find
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* entry - The location to return information about the inode.
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*
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* Returned Value:
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* Zero is returned on success. Otherwise, a negated errno is returned
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* that indicates the nature of the failure.
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*
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****************************************************************************/
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int nxffs_findinode(FAR struct nxffs_volume_s *volume, FAR const char *name,
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FAR struct nxffs_entry_s *entry)
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{
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off_t offset;
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int ret;
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/* Start with the first valid inode that was discovered when the volume
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* was created (or modified after the last file system re-packing).
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*/
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offset = volume->inoffset;
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/* Loop, checking each NXFFS inode until either: (1) we find the NXFFS inode
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* with the matching name, or (2) we reach the end of data written on the
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|
|
* media.
|
||
|
|
*/
|
||
|
|
|
||
|
|
for (;;)
|
||
|
|
{
|
||
|
|
/* Get the next, valid NXFFS inode entry */
|
||
|
|
|
||
|
|
ret = nxffs_nextentry(volume, offset, entry);
|
||
|
|
if (ret < 0)
|
||
|
|
{
|
||
|
|
fvdbg("No inode found: %d\n", -ret);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Is this the NXFFS inode we are looking for? */
|
||
|
|
|
||
|
|
else if (strcmp(name, entry->name) == 0)
|
||
|
|
{
|
||
|
|
/* Yes, return success with the entry data in 'entry' */
|
||
|
|
|
||
|
|
return OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Discard this entry and try the next one. Here we set the
|
||
|
|
* next offset using the raw data length as the offset
|
||
|
|
* increment. This is, of course, not accurate because it
|
||
|
|
* does not account for the data headers that enclose the
|
||
|
|
* data. But it is guaranteed to be less than or equal to
|
||
|
|
* the correct offset and, hence, better then searching
|
||
|
|
* byte-for-byte.
|
||
|
|
*/
|
||
|
|
|
||
|
|
offset = nxffs_inodeend(volume, entry);
|
||
|
|
nxffs_freeentry(entry);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* We won't get here, but for some compilers: */
|
||
|
|
|
||
|
|
return -ENOENT;
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: nxffs_inodeend
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* Return an *approximiate* FLASH offset to end of the inode data. The
|
||
|
|
* returned value is guaranteed to be be less then or equal to the offset
|
||
|
|
* of the thing-of-interest in FLASH. Parsing for interesting things
|
||
|
|
* can begin at that point.
|
||
|
|
*
|
||
|
|
* Assumption: The inode header has been verified by the caller and is
|
||
|
|
* known to contain valid data.
|
||
|
|
*
|
||
|
|
* Input Parameters:
|
||
|
|
* volume - Describes the NXFFS volume
|
||
|
|
* entry - Describes the inode.
|
||
|
|
*
|
||
|
|
* Returned Value:
|
||
|
|
* A FLASH offset to the (approximate) end of the inode data. No errors
|
||
|
|
* are detected.
|
||
|
|
*
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
off_t nxffs_inodeend(FAR struct nxffs_volume_s *volume,
|
||
|
|
FAR struct nxffs_entry_s *entry)
|
||
|
|
{
|
||
|
|
/* A zero length file will have no data blocks */
|
||
|
|
|
||
|
|
if (entry->doffset)
|
||
|
|
{
|
||
|
|
/* This is the maximum size of one data block. It is the physcal size
|
||
|
|
* of the block minus the minimum number of headers: block sna data
|
||
|
|
*/
|
||
|
|
|
||
|
|
uint16_t maxsize = volume->geo.blocksize - SIZEOF_NXFFS_BLOCK_HDR - SIZEOF_NXFFS_DATA_HDR;
|
||
|
|
|
||
|
|
/* This is the minimum number of blocks require to span all of the
|
||
|
|
* inode data. One additional block could possibly be required -- we
|
||
|
|
* could make this accurate by looking at the size of the first, perhaps
|
||
|
|
* partial, data block.
|
||
|
|
*/
|
||
|
|
|
||
|
|
off_t minblocks = (entry->datlen + maxsize - 1) / maxsize;
|
||
|
|
|
||
|
|
/* And this is our best, simple guess at the end of the inode data */
|
||
|
|
|
||
|
|
return entry->doffset + entry->datlen + minblocks * SIZEOF_NXFFS_DATA_HDR;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Otherwise, return an offset that accounts only for the inode header and
|
||
|
|
* the inode name.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* All valid inodes will have a name associated with them */
|
||
|
|
|
||
|
|
DEBUGASSERT(entry->noffset);
|
||
|
|
return entry->noffset + strlen(entry->name);
|
||
|
|
}
|
||
|
|
|
||
|
|
|