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incubator-nuttx/fs/nxffs/nxffs_open.c

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/****************************************************************************
* fs/nxffs/nxffs_open.c
*
* Copyright (C) 2011, 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References: Linux/Documentation/filesystems/romfs.txt
*
* 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 <string.h>
#include <fcntl.h>
#include <time.h>
#include <crc32.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mtd/mtd.h>
#include "nxffs.h"
/****************************************************************************
* Private Data
****************************************************************************/
/* Since we are limited to a single file opened for writing, it makes sense
* to pre-allocate the write state structure.
*/
#ifdef CONFIG_NXFFS_PREALLOCATED
static struct nxffs_wrfile_s g_wrfile;
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxffs_hdrpos
*
* Description:
* Find a valid location for the inode header. A valid location will have
* these properties:
*
* 1. It will lie in the free flash region.
* 2. It will have enough contiguous memory to hold the entire header
* (excluding the file name which may lie in the next block).
* 3. The memory at this location will be fully erased.
*
* This function will only perform the checks of 1) and 2).
*
* Input Parameters:
* volume - Describes the NXFFS volume
* wrfile - Contains the current guess for the header position. On
* successful return, this field will hold the selected header
* position.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure. Of special interest
* the return error of -ENOSPC which means that the FLASH volume is
* full and should be repacked.
*
* On successful return the following are also valid:
*
* wrfile->ofile.entry.hoffset - FLASH offset to candidate header position
* volume->ioblock - Read/write block number of the block containing the
* header position
* volume->iooffset - The offset in the block to the candidate header
* position.
* volume->froffset - Updated offset to the first free FLASH block.
*
****************************************************************************/
static inline int nxffs_hdrpos(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_wrfile_s *wrfile)
{
int ret;
/* Reserve memory for the object */
ret = nxffs_wrreserve(volume, SIZEOF_NXFFS_INODE_HDR);
if (ret == OK)
{
/* Save the offset to the FLASH region reserved for the inode header */
wrfile->ofile.entry.hoffset = nxffs_iotell(volume);
}
return ret;
}
/****************************************************************************
* Name: nxffs_nampos
*
* Description:
* Find a valid location for the inode name. A valid location will have
* these properties:
*
* 1. It will lie in the free flash region.
* 2. It will have enough contiguous memory to hold the entire name
* 3. The memory at this location will be fully erased.
*
* This function will only perform the checks of 1) and 2).
*
* Input Parameters:
* volume - Describes the NXFFS volume
* wrfile - Contains the current guess for the name position. On
* successful return, this field will hold the selected name
* position.
* namlen - The length of the name.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure. Of special interest
* the return error of -ENOSPC which means that the FLASH volume is
* full and should be repacked.
*
* On successful return the following are also valid:
*
* wrfile->ofile.entry.noffset - FLASH offset to candidate name position
* volume->ioblock - Read/write block number of the block containing the
* name position
* volume->iooffset - The offset in the block to the candidate name
* position.
* volume->froffset - Updated offset to the first free FLASH block.
*
****************************************************************************/
static inline int nxffs_nampos(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_wrfile_s *wrfile,
int namlen)
{
int ret;
/* Reserve memory for the object */
ret = nxffs_wrreserve(volume, namlen);
if (ret == OK)
{
/* Save the offset to the FLASH region reserved for the inode name */
wrfile->ofile.entry.noffset = nxffs_iotell(volume);
}
return ret;
}
/****************************************************************************
* Name: nxffs_hdrerased
*
* Description:
* Find a valid location for the inode header. A valid location will have
* these properties:
*
* 1. It will lie in the free flash region.
* 2. It will have enough contiguous memory to hold the entire header
* (excluding the file name which may lie in the next block).
* 3. The memory at this location will be fully erased.
*
* This function will only perform the check 3).
*
* On entry it assumes:
*
* volume->ioblock - Read/write block number of the block containing the
* header position
* volume->iooffset - The offset in the block to the candidate header
* position.
*
* Input Parameters:
* volume - Describes the NXFFS volume
* wrfile - Contains the current guess for the header position. On
* successful return, this field will hold the selected header
* position.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure. Of special interest
* the return error of -ENOSPC which means that the FLASH volume is
* full and should be repacked.
*
* On successful return the following are also valid:
*
* wrfile->ofile.entry.hoffset - FLASH offset to candidate header position
* volume->ioblock - Read/write block number of the block containing the
* header position
* volume->iooffset - The offset in the block to the candidate header
* position.
* volume->froffset - Updated offset to the first free FLASH block.
*
****************************************************************************/
static inline int nxffs_hdrerased(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_wrfile_s *wrfile)
{
int ret;
/* Find a valid location to save the inode header */
ret = nxffs_wrverify(volume, SIZEOF_NXFFS_INODE_HDR);
if (ret == OK)
{
/* This is where we will put the header */
wrfile->ofile.entry.hoffset = nxffs_iotell(volume);
}
return ret;
}
/****************************************************************************
* Name: nxffs_namerased
*
* Description:
* Find a valid location for the inode name. A valid location will have
* these properties:
*
* 1. It will lie in the free flash region.
* 2. It will have enough contiguous memory to hold the entire name
* (excluding the file name which may lie in the next block).
* 3. The memory at this location will be fully erased.
*
* This function will only perform the check 3).
*
* On entry it assumes:
*
* volume->ioblock - Read/write block number of the block containing the
* name position
* volume->iooffset - The offset in the block to the candidate name
* position.
*
* Input Parameters:
* volume - Describes the NXFFS volume
* wrfile - Contains the current guess for the name position. On
* successful return, this field will hold the selected name
* position.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure. Of special interest
* the return error of -ENOSPC which means that the FLASH volume is
* full and should be repacked.
*
* On successful return the following are also valid:
*
* wrfile->ofile.entry.noffset - FLASH offset to candidate name position
* volume->ioblock - Read/write block number of the block containing the
* name position
* volume->iooffset - The offset in the block to the candidate name
* position.
* volume->froffset - Updated offset to the first free FLASH block.
*
****************************************************************************/
static inline int nxffs_namerased(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_wrfile_s *wrfile,
int namlen)
{
int ret;
/* Find a valid location to save the inode name */
ret = nxffs_wrverify(volume, namlen);
if (ret == OK)
{
/* This is where we will put the name */
wrfile->ofile.entry.noffset = nxffs_iotell(volume);
}
return ret;
}
/****************************************************************************
* Name: nxffs_wrname
*
* Description:
* Write the inode name to cache at the position verified by
* nxffs_namerased().
*
* On entry it assumes:
*
* entry->noffset - FLASH offset to final name position
* volume->ioblock - Read/write block number of the block containing the
* name position
* volume->iooffset - The offset in the block to the candidate name
* position.
*
* Input Parameters:
* volume - Describes the NXFFS volume
* entry - Describes the entry to be written.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure.
*
****************************************************************************/
static inline int nxffs_wrname(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_entry_s *entry,
int namlen)
{
int ret;
/* Seek to the inode name position and assure that it is in the volume
* cache.
*/
nxffs_ioseek(volume, entry->noffset);
ret = nxffs_rdcache(volume, volume->ioblock);
if (ret < 0)
{
ferr("ERROR: Failed to read inode name block %d: %d\n",
volume->ioblock, -ret);
return ret;
}
/* Copy the inode name to the volume cache and write the inode name block */
memcpy(&volume->cache[volume->iooffset], entry->name, namlen);
ret = nxffs_wrcache(volume);
if (ret < 0)
{
ferr("ERROR: Failed to write inode header block %d: %d\n",
volume->ioblock, -ret);
}
return ret;
}
/****************************************************************************
* Name: nxffs_wropen
*
* Description:
* Handle opening for writing. Only a single writer is permitted and only
* file creation is supported.
*
****************************************************************************/
static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
FAR const char *name, mode_t oflags,
FAR struct nxffs_ofile_s **ppofile)
{
FAR struct nxffs_wrfile_s *wrfile;
FAR struct nxffs_entry_s entry;
bool packed;
bool truncate = false;
int namlen;
int ret;
/* Limitation: Only a single writer is permitted. Writing may involve
* extension of the file system in FLASH. Since files are contiguous
* in FLASH, only a single file may be extending the FLASH region.
*/
ret = sem_wait(&volume->wrsem);
if (ret != OK)
{
ferr("ERROR: sem_wait failed: %d\n", ret);
ret = -get_errno();
goto errout;
}
/* Get exclusive access to the volume. Note that the volume exclsem
* protects the open file list. Note that exclsem is ALWAYS taken
* after wrsem to avoid deadlocks.
*/
ret = sem_wait(&volume->exclsem);
if (ret != OK)
{
ferr("ERROR: sem_wait failed: %d\n", ret);
ret = -get_errno();
goto errout_with_wrsem;
}
/* Check if the file exists */
ret = nxffs_findinode(volume, name, &entry);
if (ret == OK)
{
FAR struct nxffs_ofile_s *ofile;
/* It exists. Release the entry. */
nxffs_freeentry(&entry);
/* Is the file already open for reading? */
ofile = nxffs_findofile(volume, name);
if (ofile)
{
/* The file is already open.
* Limitation: Files cannot be open both for reading and writing.
*/
ferr("ERROR: File is open for reading\n");
ret = -ENOSYS;
goto errout_with_exclsem;
}
/* It would be an error if we are asked to create the file
* exclusively.
*/
else if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
{
ferr("ERROR: File exists, can't create O_EXCL\n");
ret = -EEXIST;
goto errout_with_exclsem;
}
/* Were we asked to truncate the file? NOTE: Don't truncate the
* file if we were not also asked to created it. See below...
* we will not re-create the file unless O_CREAT is also specified.
*/
else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
{
/* Just schedule the removal the file and fall through to re-create it.
* Note that the old file of the same name will not actually be removed
* until the new file is successfully written.
*/
truncate = true;
}
/* The file exists and we were not asked to truncate (and recreate) it.
* Limitation: Cannot write to existing files.
*/
else
{
ferr("ERROR: File %s exists and we were not asked to truncate it\n");
ret = -ENOSYS;
goto errout_with_exclsem;
}
}
/* Okay, the file is not open and does not exists (maybe because we deleted
* it). Now, make sure that we were asked to created it.
*/
if ((oflags & O_CREAT) == 0)
{
ferr("ERROR: Not asked to create the file\n");
ret = -ENOENT;
goto errout_with_exclsem;
}
/* Make sure that the length of the file name will fit in a uint8_t */
namlen = strlen(name);
if (namlen > CONFIG_NXFFS_MAXNAMLEN)
{
ferr("ERROR: Name is too long: %d\n", namlen);
ret = -EINVAL;
goto errout_with_exclsem;
}
/* Yes.. Create a new structure that will describe the state of this open
* file. NOTE that a special variant of the open file structure is used
* that includes additional information to support the write operation.
*/
#ifdef CONFIG_NXFFS_PREALLOCATED
wrfile = &g_wrfile;
memset(wrfile, 0, sizeof(struct nxffs_wrfile_s));
#else
wrfile = (FAR struct nxffs_wrfile_s *)kmm_zalloc(sizeof(struct nxffs_wrfile_s));
if (!wrfile)
{
ret = -ENOMEM;
goto errout_with_exclsem;
}
#endif
/* Initialize the open file state structure */
wrfile->ofile.crefs = 1;
wrfile->ofile.oflags = oflags;
wrfile->ofile.entry.utc = time(NULL);
wrfile->truncate = truncate;
/* Save a copy of the inode name. */
wrfile->ofile.entry.name = strdup(name);
if (!wrfile->ofile.entry.name)
{
ret = -ENOMEM;
goto errout_with_ofile;
}
/* Allocate FLASH memory for the file and set up for the write.
*
* Loop until the inode header is configured or until a failure occurs.
* Note that nothing is written to FLASH. The inode header is not
* written until the file is closed.
*/
packed = false;
for (; ; )
{
/* File a valid location to position the inode header. Start with the
* first byte in the free FLASH region.
*/
ret = nxffs_hdrpos(volume, wrfile);
if (ret == OK)
{
/* Find a region of memory in the block that is fully erased */
ret = nxffs_hdrerased(volume, wrfile);
if (ret == OK)
{
/* Valid memory for the inode header was found. Break out of
* the loop.
*/
break;
}
}
/* If no valid memory is found searching to the end of the volume,
* then -ENOSPC will be returned. Other errors are not handled.
*/
if (ret != -ENOSPC || packed)
{
ferr("ERROR: Failed to find inode header memory: %d\n", -ret);
goto errout_with_name;
}
/* -ENOSPC is a special case.. It means that the volume is full.
* Try to pack the volume in order to free up some space.
*/
ret = nxffs_pack(volume);
if (ret < 0)
{
ferr("ERROR: Failed to pack the volume: %d\n", -ret);
goto errout_with_name;
}
/* After packing the volume, froffset will be updated to point to the
* new free flash region. Try again.
*/
packed = true;
}
/* Loop until the inode name is configured or until a failure occurs.
* Note that nothing is written to FLASH.
*/
for (; ; )
{
/* File a valid location to position the inode name. Start with the
* first byte in the free FLASH region.
*/
ret = nxffs_nampos(volume, wrfile, namlen);
if (ret == OK)
{
/* Find a region of memory in the block that is fully erased */
ret = nxffs_namerased(volume, wrfile, namlen);
if (ret == OK)
{
/* Valid memory for the inode header was found. Write the
* inode name to this location.
*/
ret = nxffs_wrname(volume, &wrfile->ofile.entry, namlen);
if (ret < 0)
{
ferr("ERROR: Failed to write the inode name: %d\n", -ret);
goto errout_with_name;
}
/* Then just break out of the loop reporting success. Note
* that the alllocated inode name string is retained; it
* will be needed later to calculate the inode CRC.
*/
break;
}
}
/* If no valid memory is found searching to the end of the volume,
* then -ENOSPC will be returned. Other errors are not handled.
*/
if (ret != -ENOSPC || packed)
{
ferr("ERROR: Failed to find inode name memory: %d\n", -ret);
goto errout_with_name;
}
/* -ENOSPC is a special case.. It means that the volume is full.
* Try to pack the volume in order to free up some space.
*/
ret = nxffs_pack(volume);
if (ret < 0)
{
ferr("ERROR: Failed to pack the volume: %d\n", -ret);
goto errout_with_name;
}
/* After packing the volume, froffset will be updated to point to the
* new free flash region. Try again.
*/
packed = true;
}
/* Add the open file structure to the head of the list of open files */
wrfile->ofile.flink = volume->ofiles;
volume->ofiles = &wrfile->ofile;
/* Indicate that the volume is open for writing and return the open file
* instance. Releasing exclsem allows other readers while the write is
* in progress. But wrsem is still held for this open file, preventing
* any further writers until this inode is closed.s
*/
*ppofile = &wrfile->ofile;
sem_post(&volume->exclsem);
return OK;
errout_with_name:
kmm_free(wrfile->ofile.entry.name);
errout_with_ofile:
#ifndef CONFIG_NXFFS_PREALLOCATED
kmm_free(wrfile);
#endif
errout_with_exclsem:
sem_post(&volume->exclsem);
errout_with_wrsem:
sem_post(&volume->wrsem);
errout:
return ret;
}
/****************************************************************************
* Name: nxffs_rdopen
*
* Description:
* Open an existing file for reading.
*
****************************************************************************/
static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
FAR const char *name,
FAR struct nxffs_ofile_s **ppofile)
{
FAR struct nxffs_ofile_s *ofile;
int ret;
/* Get exclusive access to the volume. Note that the volume exclsem
* protects the open file list.
*/
ret = sem_wait(&volume->exclsem);
if (ret != OK)
{
ferr("ERROR: sem_wait failed: %d\n", ret);
ret = -get_errno();
goto errout;
}
/* Check if the file has already been opened (for reading) */
ofile = nxffs_findofile(volume, name);
if (ofile)
{
/* The file is already open.
* Limitation: Files cannot be open both for reading and writing.
*/
if ((ofile->oflags & O_WROK) != 0)
{
ferr("ERROR: File is open for writing\n");
ret = -ENOSYS;
goto errout_with_exclsem;
}
/* Just increment the reference count on the ofile */
ofile->crefs++;
finfo("crefs: %d\n", ofile->crefs);
}
/* The file has not yet been opened.
* Limitation: The file must exist. We do not support creation of files
* read-only.
*/
else
{
/* Not already open.. create a new open structure */
ofile = (FAR struct nxffs_ofile_s *)kmm_zalloc(sizeof(struct nxffs_ofile_s));
if (!ofile)
{
ferr("ERROR: ofile allocation failed\n");
ret = -ENOMEM;
goto errout_with_exclsem;
}
/* Initialize the open file state structure */
ofile->crefs = 1;
ofile->oflags = O_RDOK;
/* Find the file on this volume associated with this file name */
ret = nxffs_findinode(volume, name, &ofile->entry);
if (ret != OK)
{
finfo("Inode '%s' not found: %d\n", name, -ret);
goto errout_with_ofile;
}
/* Add the open file structure to the head of the list of open files */
ofile->flink = volume->ofiles;
volume->ofiles = ofile;
}
/* Return the open file state structure */
*ppofile = ofile;
sem_post(&volume->exclsem);
return OK;
errout_with_ofile:
kmm_free(ofile);
errout_with_exclsem:
sem_post(&volume->exclsem);
errout:
return ret;
}
/****************************************************************************
* Name: nxffs_remofile
*
* Description:
* Remove an entry from the open file list.
*
****************************************************************************/
static inline void nxffs_remofile(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_ofile_s *ofile)
{
FAR struct nxffs_ofile_s *prev;
FAR struct nxffs_ofile_s *curr;
/* Find the open file structure to be removed */
for (prev = NULL, curr = volume->ofiles;
curr && curr != ofile;
prev = curr, curr = curr->flink);
/* Was it found? */
if (curr)
{
/* Yes.. at the head of the list? */
if (prev)
{
prev->flink = ofile->flink;
}
else
{
volume->ofiles = ofile->flink;
}
}
else
{
ferr("ERROR: Open inode %p not found\n", ofile);
}
}
/****************************************************************************
* Name: nxffs_freeofile
*
* Description:
* Free resources held by an open file.
*
****************************************************************************/
static inline void nxffs_freeofile(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_ofile_s *ofile)
{
/* Release the open file entry */
nxffs_freeentry(&ofile->entry);
/* Then free the open file container (unless this the pre-alloated
* write-only open file container)
*/
#ifdef CONFIG_NXFFS_PREALLOCATED
if ((FAR struct nxffs_wrfile_s *)ofile != &g_wrfile)
#endif
{
kmm_free(ofile);
}
}
/****************************************************************************
* Name: nxffs_wrclose
*
* Description:
* Perform special operations when a file is closed:
* 1. Write the file block header
* 2. Remove any file with the same name that was discovered when the
* file was open for writing, and finally,
* 3. Write the new file inode.
*
* Input parameters
* volume - Describes the NXFFS volume
* wrfile - Describes the state of the open file
*
****************************************************************************/
static inline int nxffs_wrclose(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_wrfile_s *wrfile)
{
int ret;
/* Is there an unfinalized write data? */
if (wrfile->datlen > 0)
{
/* Yes.. Write the final file block header */
ret = nxffs_wrblkhdr(volume, wrfile);
if (ret < 0)
{
ferr("ERROR: Failed to write the final block of the file: %d\n", -ret);
goto errout;
}
}
/* Truncation is implemented by writing the new file, then deleting the
* older version of the file. Note that we removed the entry from the
* open file list earlier in the close sequence; this will prevent the
* open file check from failing when we remove the old version of the
* file.
*/
if (wrfile->truncate && wrfile->ofile.entry.name)
{
finfo("Removing old file: %s\n", wrfile->ofile.entry.name);
ret = nxffs_rminode(volume, wrfile->ofile.entry.name);
if (ret < 0)
{
ferr("ERROR: nxffs_rminode failed: %d\n", -ret);
goto errout;
}
}
/* Write the inode header to FLASH */
ret = nxffs_wrinode(volume, &wrfile->ofile.entry);
/* The volume is now available for other writers */
errout:
sem_post(&volume->wrsem);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxffs_findofile
*
* Description:
* Search the list of already opened files to see if the inode of this
* name is one of the opened files.
*
* Input Parameters:
* name - The name of the inode to check.
*
* Returned Value:
* If an inode of this name is found in the list of opened inodes, then
* a reference to the open file structure is returned. NULL is returned
* otherwise.
*
****************************************************************************/
FAR struct nxffs_ofile_s *nxffs_findofile(FAR struct nxffs_volume_s *volume,
FAR const char *name)
{
FAR struct nxffs_ofile_s *ofile;
/* Check every open file. Note that the volume exclsem protects the
* list of open files.
*/
for (ofile = volume->ofiles; ofile; ofile = ofile->flink)
{
/* Check for a name match */
if (strcmp(name, ofile->entry.name) == 0)
{
return ofile;
}
}
return NULL;
}
/****************************************************************************
* Name: nxffs_findwriter
*
* Description:
* Search the list of already opened files and return the open file
* instance for the write.
*
* Input Parameters:
* volume - Describes the NXFFS volume.
*
* Returned Value:
* If there is an active writer of the volume, its open file instance is
* returned. NULL is returned otherwise.
*
****************************************************************************/
FAR struct nxffs_wrfile_s *nxffs_findwriter(FAR struct nxffs_volume_s *volume)
{
/* We can tell if the write is in-use because it will have an allocated
* name attached.
*/
#ifdef CONFIG_NXFFS_PREALLOCATED
return g_wrfile.ofile.entry.name != NULL ? &g_wrfile : NULL;
#else
# error "Missing implementation"
#endif
}
/****************************************************************************
* Name: nxffs_open
*
* Description:
* This is the standard mountpoint open method.
*
****************************************************************************/
int nxffs_open(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode)
{
FAR struct nxffs_volume_s *volume;
FAR struct nxffs_ofile_s *ofile = NULL;
int ret;
finfo("Open '%s'\n", relpath);
/* Sanity checks */
DEBUGASSERT(filep->f_priv == NULL && filep->f_inode != NULL);
/* Get the mountpoint private data from the NuttX inode reference in the
* file structure
*/
volume = (FAR struct nxffs_volume_s *)filep->f_inode->i_private;
DEBUGASSERT(volume != NULL);
#ifdef CONFIG_FILE_MODE
# warning "Missing check for privileges based on inode->i_mode"
#endif
/* Limitation: A file must be opened for reading or writing, but not both.
* There is no general way of extending the size of a file. Extending the
* file size of possible if the file to be extended is the last in the
* sequence on FLASH, but since that case is not the general case, no file
* extension is supported.
*/
switch (oflags & (O_WROK | O_RDOK))
{
case 0:
default:
ferr("ERROR: One of O_WRONLY/O_RDONLY must be provided\n");
return -EINVAL;
case O_WROK:
ret = nxffs_wropen(volume, relpath, oflags, &ofile);
break;
case O_RDOK:
ret = nxffs_rdopen(volume, relpath, &ofile);
break;
case O_WROK | O_RDOK:
ferr("ERROR: O_RDWR is not supported\n");
return -ENOSYS;
}
/* Save the reference to the open-specific state in filep->f_priv */
if (ret == OK)
{
filep->f_priv = ofile;
}
return ret;
}
/****************************************************************************
* Name: binfs_dup
*
* Description:
* Duplicate open file data in the new file structure.
*
****************************************************************************/
int nxffs_dup(FAR const struct file *oldp, FAR struct file *newp)
{
#ifdef CONFIG_DEBUG_ASSERTIONS
FAR struct nxffs_volume_s *volume;
#endif
FAR struct nxffs_ofile_s *ofile;
finfo("Dup %p->%p\n", oldp, newp);
/* Sanity checks */
#ifdef CONFIG_DEBUG_ASSERTIONS
DEBUGASSERT(oldp->f_priv == NULL && oldp->f_inode != NULL);
/* Get the mountpoint private data from the NuttX inode reference in the
* file structure
*/
volume = (FAR struct nxffs_volume_s *)oldp->f_inode->i_private;
DEBUGASSERT(volume != NULL);
#endif
/* Recover the open file state from the struct file instance */
ofile = (FAR struct nxffs_ofile_s *)oldp->f_priv;
/* I do not think we need exclusive access to the volume to do this.
* The volume exclsem protects the open file list and, hence, would
* assure that the ofile is stable. However, it is assumed that the
* caller holds a value file descriptor associated with this ofile,
* so it should be stable throughout the life of this function.
*/
/* Limitations: I do not think we have to be concerned about the
* usual NXFFS file limitations here: dup'ing cannot resulting
* in mixed reading and writing to the same file, or multiple
* writer to different file.
*
* I notice that nxffs_wropen will prohibit multiple opens for
* writing. But I do not thing that dup'ing a file already opened
* for writing suffers from any of these issues.
*/
/* Just increment the reference count on the ofile */
ofile->crefs++;
newp->f_priv = (FAR void *)ofile;
return OK;
}
/****************************************************************************
* Name: nxffs_close
*
* Description:
* This is the standard mountpoint close method.
*
****************************************************************************/
int nxffs_close(FAR struct file *filep)
{
FAR struct nxffs_volume_s *volume;
FAR struct nxffs_ofile_s *ofile;
int ret;
finfo("Closing\n");
/* Sanity checks */
DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
/* Recover the open file state from the struct file instance */
ofile = (FAR struct nxffs_ofile_s *)filep->f_priv;
/* Recover the volume state from the open file */
volume = (FAR struct nxffs_volume_s *)filep->f_inode->i_private;
DEBUGASSERT(volume != NULL);
/* Get exclusive access to the volume. Note that the volume exclsem
* protects the open file list.
*/
ret = sem_wait(&volume->exclsem);
if (ret != OK)
{
ret = -get_errno();
ferr("ERROR: sem_wait failed: %d\n", ret);
goto errout;
}
/* Decrement the reference count on the open file */
ret = OK;
if (ofile->crefs == 1)
{
/* Decrementing the reference count would take it zero.
*
* Remove the entry from the open file list. We do this early
* to avoid some chick-and-egg problems with file truncation.
*/
nxffs_remofile(volume, ofile);
/* Handle special finalization of the write operation. */
if ((ofile->oflags & O_WROK) != 0)
{
ret = nxffs_wrclose(volume, (FAR struct nxffs_wrfile_s *)ofile);
}
/* Release all resouces held by the open file */
nxffs_freeofile(volume, ofile);
}
else
{
/* Just decrement the reference count */
ofile->crefs--;
}
filep->f_priv = NULL;
sem_post(&volume->exclsem);
errout:
return ret;
}
/****************************************************************************
* Name: nxffs_wrinode
*
* Description:
* Write the inode header (only to FLASH. This is done in two contexts:
*
* 1. When an inode is closed, or
* 2. As part of the file system packing logic when an inode is moved.
*
* Note that in either case, the inode name has already been written to
* FLASH.
*
* Input parameters
* volume - Describes the NXFFS volume
* entry - Describes the inode header to write
*
* Returned Value:
* Zero is returned on success; Otherwise, a negated errno value is returned
* indicating the nature of the failure.
*
****************************************************************************/
int nxffs_wrinode(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_entry_s *entry)
{
FAR struct nxffs_inode_s *inode;
uint32_t crc;
int namlen;
int ret;
/* Seek to the inode header position and assure that it is in the volume
* cache.
*/
nxffs_ioseek(volume, entry->hoffset);
ret = nxffs_rdcache(volume, volume->ioblock);
if (ret < 0)
{
ferr("ERROR: Failed to read inode header block %d: %d\n",
volume->ioblock, -ret);
goto errout;
}
/* Get the length of the inode name */
namlen = strlen(entry->name);
DEBUGASSERT(namlen < CONFIG_NXFFS_MAXNAMLEN); /* This was verified earlier */
/* Initialize the inode header */
inode = (FAR struct nxffs_inode_s *)&volume->cache[volume->iooffset];
memcpy(inode->magic, g_inodemagic, NXFFS_MAGICSIZE);
inode->state = CONFIG_NXFFS_ERASEDSTATE;
inode->namlen = namlen;
nxffs_wrle32(inode->noffs, entry->noffset);
nxffs_wrle32(inode->doffs, entry->doffset);
nxffs_wrle32(inode->utc, entry->utc);
nxffs_wrle32(inode->crc, 0);
nxffs_wrle32(inode->datlen, entry->datlen);
/* Calculate the CRC */
crc = crc32((FAR const uint8_t *)inode, SIZEOF_NXFFS_INODE_HDR);
crc = crc32part((FAR const uint8_t *)entry->name, namlen, crc);
/* Finish the inode header */
inode->state = INODE_STATE_FILE;
nxffs_wrle32(inode->crc, crc);
/* Write the block with the inode header */
ret = nxffs_wrcache(volume);
if (ret < 0)
{
ferr("ERROR: Failed to write inode header block %d: %d\n",
volume->ioblock, -ret);
}
/* The volume is now available for other writers */
errout:
sem_post(&volume->wrsem);
return ret;
}
/****************************************************************************
* Name: nxffs_updateinode
*
* Description:
* The packing logic has moved an inode. Check if any open files are using
* this inode and, if so, move the data in the open file structure as well.
*
* Input parameters
* volume - Describes the NXFFS volume
* entry - Describes the new inode entry
*
* Returned Value:
* Zero is returned on success; Otherwise, a negated errno value is returned
* indicating the nature of the failure.
*
****************************************************************************/
int nxffs_updateinode(FAR struct nxffs_volume_s *volume,
FAR struct nxffs_entry_s *entry)
{
FAR struct nxffs_ofile_s *ofile;
/* Find the open inode structure matching this name */
ofile = nxffs_findofile(volume, entry->name);
if (ofile)
{
/* Yes.. the file is open. Update the FLASH offsets to inode headers */
ofile->entry.hoffset = entry->hoffset;
ofile->entry.noffset = entry->noffset;
ofile->entry.doffset = entry->doffset;
}
return OK;
}
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