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incubator-nuttx/fs/romfs/fs_romfsutil.c

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/****************************************************************************
* rm/romfs/fs_romfsutil.c
*
* Copyright (C) 2008-2009, 2013, 2017 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 <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/fs/dirent.h>
#include <nuttx/mtd/mtd.h>
#include "fs_romfs.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: romfs_devread32
*
* Description:
* Read the big-endian 32-bit value from the mount device buffer
*
* Assumption:
* All values are aligned to 32-bit boundaries
*
****************************************************************************/
static uint32_t romfs_devread32(struct romfs_mountpt_s *rm, int ndx)
{
return ((((uint32_t)rm->rm_buffer[ndx] & 0xff) << 24) |
(((uint32_t)rm->rm_buffer[ndx + 1] & 0xff) << 16) |
(((uint32_t)rm->rm_buffer[ndx + 2] & 0xff) << 8) |
((uint32_t)rm->rm_buffer[ndx + 3] & 0xff));
}
/****************************************************************************
* Name: romfs_checkentry
*
* Description:
* Check if the entry at offset is a directory or file path segment
*
****************************************************************************/
static inline int romfs_checkentry(struct romfs_mountpt_s *rm,
uint32_t offset, const char *entryname,
int entrylen,
struct romfs_dirinfo_s *dirinfo)
{
char name[NAME_MAX + 1];
uint32_t linkoffset;
uint32_t next;
uint32_t info;
uint32_t size;
int ret;
/* Parse the directory entry at this offset (which may be re-directed
* to some other entry if HARLINKED).
*/
ret = romfs_parsedirentry(rm, offset, &linkoffset, &next, &info, &size);
if (ret < 0)
{
return ret;
}
/* Now we are pointing to the real entry of interest. Is it a
* directory? Or a file?
*/
if (IS_DIRECTORY(next) || IS_FILE(next))
{
/* Get the name of the directory entry. */
ret = romfs_parsefilename(rm, offset, name);
if (ret < 0)
{
return ret;
}
/* Then check if this the name segment we are looking for. The
* string comparison is awkward because there is no terminator
* on entryname (there is a terminator on name, however)
*/
if (memcmp(entryname, name, entrylen) == 0 &&
strlen(name) == entrylen)
{
/* Found it -- save the component info and return success */
if (IS_DIRECTORY(next))
{
dirinfo->rd_dir.fr_firstoffset = info;
dirinfo->rd_dir.fr_curroffset = info;
dirinfo->rd_size = 0;
}
else
{
dirinfo->rd_dir.fr_curroffset = offset;
dirinfo->rd_size = size;
}
dirinfo->rd_next = next;
return OK;
}
}
/* The entry is not a directory or it does not have the matching name */
return -ENOENT;
}
/****************************************************************************
* Name: romfs_devcacheread
*
* Description:
* Read the specified sector for specified offset into the sector cache.
* Return the index into the sector corresponding to the offset
*
****************************************************************************/
int16_t romfs_devcacheread(struct romfs_mountpt_s *rm, uint32_t offset)
{
uint32_t sector;
int ret;
/* rm->rm_cachesector holds the current sector that is buffer in or referenced
* by rm->tm_buffer. If the requested sector is the same as this sector,
* then we do nothing.
*/
sector = SEC_NSECTORS(rm, offset);
if (rm->rm_cachesector != sector)
{
/* Check the access mode */
if (rm->rm_xipbase)
{
/* In XIP mode, rf_buffer is just an offset pointer into the device
* address space.
*/
rm->rm_buffer = rm->rm_xipbase + SEC_ALIGN(rm, offset);
}
else
{
/* In non-XIP mode, we will have to read the new sector. */
ret = romfs_hwread(rm, rm->rm_buffer, sector, 1);
if (ret < 0)
{
return (int16_t)ret;
}
}
/* Update the cached sector number */
rm->rm_cachesector = sector;
}
/* Return the offset */
return offset & SEC_NDXMASK(rm);
}
/****************************************************************************
* Name: romfs_followhardlinks
*
* Description:
* Given the offset to a file header, check if the file is a hardlink.
* If so, traverse the hard links until the terminal, non-linked header
* so found and return that offset.
*
****************************************************************************/
static int romfs_followhardlinks(struct romfs_mountpt_s *rm, uint32_t offset,
uint32_t *poffset)
{
uint32_t next;
int16_t ndx;
int i;
/* Loop while we are redirected by hardlinks */
for (i = 0; i < ROMF_MAX_LINKS; i++)
{
/* Read the sector containing the offset into memory */
ndx = romfs_devcacheread(rm, offset);
if (ndx < 0)
{
return ndx;
}
/* Check if this is a hard link */
next = romfs_devread32(rm, ndx + ROMFS_FHDR_NEXT);
if (!IS_HARDLINK(next))
{
*poffset = offset;
return OK;
}
/* Follow the hard-link */
offset = romfs_devread32(rm, ndx + ROMFS_FHDR_INFO);
}
return -ELOOP;
}
/****************************************************************************
* Name: romfs_searchdir
*
* Description:
* This is part of the romfs_finddirentry log. Search the directory
* beginning at dirinfo->fr_firstoffset for entryname.
*
****************************************************************************/
static inline int romfs_searchdir(struct romfs_mountpt_s *rm,
const char *entryname, int entrylen,
struct romfs_dirinfo_s *dirinfo)
{
uint32_t offset;
uint32_t next;
int16_t ndx;
int ret;
/* Then loop through the current directory until the directory
* with the matching name is found. Or until all of the entries
* the directory have been examined.
*/
offset = dirinfo->rd_dir.fr_firstoffset;
do
{
/* Read the sector into memory (do this before calling
* romfs_checkentry() so we won't have to read the sector
* twice in the event that the offset refers to a hardlink).
*/
ndx = romfs_devcacheread(rm, offset);
if (ndx < 0)
{
return ndx;
}
/* Because everything is chunked and aligned to 16-bit boundaries,
* we know that most the basic node info fits into the sector.
*/
next = romfs_devread32(rm, ndx + ROMFS_FHDR_NEXT) & RFNEXT_OFFSETMASK;
/* Check if the name this entry is a directory with the matching
* name
*/
ret = romfs_checkentry(rm, offset, entryname, entrylen, dirinfo);
if (ret == OK)
{
/* Its a match! Return success */
return OK;
}
/* No match... select the offset to the next entry */
offset = next;
}
while (next != 0);
/* There is nothing in this directory with that name */
return -ENOENT;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: romfs_semtake
****************************************************************************/
void romfs_semtake(struct romfs_mountpt_s *rm)
{
nxsem_wait_uninterruptible(&rm->rm_sem);
}
/****************************************************************************
* Name: romfs_semgive
****************************************************************************/
void romfs_semgive(struct romfs_mountpt_s *rm)
{
nxsem_post(&rm->rm_sem);
}
/****************************************************************************
* Name: romfs_hwread
*
* Description: Read the specified sector into the sector buffer
*
****************************************************************************/
int romfs_hwread(struct romfs_mountpt_s *rm, uint8_t *buffer, uint32_t sector,
unsigned int nsectors)
{
int ret = OK;
/* Check the access mode */
if (rm->rm_xipbase)
{
/* In XIP mode, we just copy the requested data */
memcpy(buffer,
rm->rm_xipbase + sector*rm->rm_hwsectorsize,
nsectors*rm->rm_hwsectorsize);
}
else
{
/* In non-XIP mode, we have to read the data from the device */
struct inode *inode = rm->rm_blkdriver;
ssize_t nsectorsread = -ENODEV;
DEBUGASSERT(inode);
if (INODE_IS_MTD(inode))
{
nsectorsread =
MTD_BREAD(inode->u.i_mtd, sector, nsectors, buffer);
}
else if (inode->u.i_bops->read)
{
nsectorsread =
inode->u.i_bops->read(inode, buffer, sector, nsectors);
}
if (nsectorsread == (ssize_t)nsectors)
{
ret = OK;
}
else if (nsectorsread < 0)
{
ret = nsectorsread;
}
}
return ret;
}
/****************************************************************************
* Name: romfs_filecacheread
*
* Description:
* Read the specified sector into the sector cache
*
****************************************************************************/
int romfs_filecacheread(struct romfs_mountpt_s *rm, struct romfs_file_s *rf,
uint32_t sector)
{
int ret;
finfo("sector: %d cached: %d sectorsize: %d XIP base: %p buffer: %p\n",
sector, rf->rf_cachesector, rm->rm_hwsectorsize,
rm->rm_xipbase, rf->rf_buffer);
/* rf->rf_cachesector holds the current sector that is buffer in or referenced
* by rf->rf_buffer. If the requested sector is the same as this sector,
* then we do nothing.
*/
if (rf->rf_cachesector != sector)
{
/* Check the access mode */
if (rm->rm_xipbase)
{
/* In XIP mode, rf_buffer is just an offset pointer into the device
* address space.
*/
rf->rf_buffer = rm->rm_xipbase + sector * rm->rm_hwsectorsize;
finfo("XIP buffer: %p\n", rf->rf_buffer);
}
else
{
/* In non-XIP mode, we will have to read the new sector. */
finfo("Calling romfs_hwread\n");
ret = romfs_hwread(rm, rf->rf_buffer, sector, 1);
if (ret < 0)
{
ferr("ERROR: romfs_hwread failed: %d\n", ret);
return ret;
}
}
/* Update the cached sector number */
rf->rf_cachesector = sector;
}
return OK;
}
/****************************************************************************
* Name: romfs_hwconfigure
*
* Description:
* This function is called as part of the ROMFS mount operation It
* configures the ROMFS filestem for use on this block driver. This includes
* the accounting for the geometry of the device, setting up any XIP modes
* of operation, and/or allocating any cache buffers.
*
****************************************************************************/
int romfs_hwconfigure(struct romfs_mountpt_s *rm)
{
struct inode *inode = rm->rm_blkdriver;
int ret;
/* Get the underlying device geometry */
#ifdef CONFIG_DEBUG_FEATURES
if (inode == NULL)
{
return -ENODEV;
}
#endif
if (INODE_IS_MTD(inode))
{
struct mtd_geometry_s mgeo;
ret = MTD_IOCTL(inode->u.i_mtd, MTDIOC_GEOMETRY,
(unsigned long)&mgeo);
if (ret != OK)
{
return ret;
}
/* Save that information in the mount structure */
rm->rm_hwsectorsize = mgeo.blocksize;
rm->rm_hwnsectors = mgeo.neraseblocks *
(mgeo.erasesize / mgeo.blocksize);
}
else
{
struct geometry geo;
ret = inode->u.i_bops->geometry(inode, &geo);
if (ret != OK)
{
return ret;
}
if (!geo.geo_available)
{
return -EBUSY;
}
/* Save that information in the mount structure */
rm->rm_hwsectorsize = geo.geo_sectorsize;
rm->rm_hwnsectors = geo.geo_nsectors;
}
/* Determine if block driver supports the XIP mode of operation */
rm->rm_cachesector = (uint32_t)-1;
if (INODE_IS_MTD(inode))
{
ret = MTD_IOCTL(inode->u.i_mtd, MTDIOC_XIPBASE,
(unsigned long)&rm->rm_xipbase);
}
else if (inode->u.i_bops->ioctl != NULL)
{
ret = inode->u.i_bops->ioctl(inode, BIOC_XIPBASE,
(unsigned long)&rm->rm_xipbase);
}
else
{
ret = -ENOTSUP;
}
if (ret == OK && rm->rm_xipbase)
{
/* Yes.. Then we will directly access the media (vs.
* copying into an allocated sector buffer.
*/
rm->rm_buffer = rm->rm_xipbase;
rm->rm_cachesector = 0;
return OK;
}
/* Allocate the device cache buffer for normal sector accesses */
rm->rm_buffer = (FAR uint8_t *)kmm_malloc(rm->rm_hwsectorsize);
if (!rm->rm_buffer)
{
return -ENOMEM;
}
return OK;
}
/****************************************************************************
* Name: romfs_fsconfigure
*
* Description:
* This function is called as part of the ROMFS mount operation It
* sets up the mount structure to include configuration information contained
* in the ROMFS header. This is the place where we actually determine if
* the media contains a ROMFS filesystem.
*
****************************************************************************/
int romfs_fsconfigure(struct romfs_mountpt_s *rm)
{
const char *name;
int16_t ndx;
/* Then get information about the ROMFS filesystem on the devices managed
* by this block driver. Read sector zero which contains the volume header.
*/
ndx = romfs_devcacheread(rm, 0);
if (ndx < 0)
{
return ndx;
}
/* Verify the magic number at that identifies this as a ROMFS filesystem */
if (memcmp(rm->rm_buffer, ROMFS_VHDR_MAGIC, 8) != 0)
{
return -EINVAL;
}
/* Then extract the values we need from the header and return success */
rm->rm_volsize = romfs_devread32(rm, ROMFS_VHDR_SIZE);
/* The root directory entry begins right after the header */
name = (FAR const char *)&rm->rm_buffer[ROMFS_VHDR_VOLNAME];
rm->rm_rootoffset = ROMFS_ALIGNUP(ROMFS_VHDR_VOLNAME + strlen(name) + 1);
/* and return success */
rm->rm_mounted = true;
return OK;
}
/****************************************************************************
* Name: romfs_fileconfigure
*
* Description:
* This function is called as part of the ROMFS file open operation It
* sets up the file structure to handle buffer appropriately, depending
* upon XIP mode or not.
*
****************************************************************************/
int romfs_fileconfigure(struct romfs_mountpt_s *rm, struct romfs_file_s *rf)
{
/* Check if XIP access mode is supported. If so, then we do not need
* to allocate anything.
*/
if (rm->rm_xipbase)
{
/* We'll put a valid address in rf_buffer just in case. */
rf->rf_cachesector = 0;
rf->rf_buffer = rm->rm_xipbase;
}
else
{
/* Nothing in the cache buffer */
rf->rf_cachesector = (uint32_t)-1;
/* Create a file buffer to support partial sector accesses */
rf->rf_buffer = (FAR uint8_t *)kmm_malloc(rm->rm_hwsectorsize);
if (!rf->rf_buffer)
{
return -ENOMEM;
}
}
return OK;
}
/****************************************************************************
* Name: romfs_checkmount
*
* Description: Check if the mountpoint is still valid.
*
* The caller should hold the mountpoint semaphore
*
****************************************************************************/
int romfs_checkmount(struct romfs_mountpt_s *rm)
{
struct inode *inode;
struct geometry geo;
int ret;
/* If the fs_mounted flag is false, then we have already handled the loss
* of the mount.
*/
DEBUGASSERT(rm && rm->rm_blkdriver);
if (rm->rm_mounted)
{
/* We still think the mount is healthy. Check an see if this is
* still the case
*/
inode = rm->rm_blkdriver;
if (INODE_IS_MTD(inode))
{
/* It is impossible to remove MTD device */
return OK;
}
else if (inode->u.i_bops->geometry)
{
ret = inode->u.i_bops->geometry(inode, &geo);
if (ret == OK && geo.geo_available && !geo.geo_mediachanged)
{
return OK;
}
}
/* If we get here, the mount is NOT healthy */
rm->rm_mounted = false;
}
return -ENODEV;
}
/****************************************************************************
* Name: romfs_finddirentry
*
* Description:
* Given a path to something that may or may not be in the file system,
* return the directory entry of the item.
*
****************************************************************************/
int romfs_finddirentry(struct romfs_mountpt_s *rm,
struct romfs_dirinfo_s *dirinfo, const char *path)
{
const char *entryname;
const char *terminator;
int entrylen;
int ret;
/* Start with the first element after the root directory */
dirinfo->rd_dir.fr_firstoffset = rm->rm_rootoffset;
dirinfo->rd_dir.fr_curroffset = rm->rm_rootoffset;
dirinfo->rd_next = RFNEXT_DIRECTORY;
dirinfo->rd_size = 0;
/* The root directory is a special case */
if (!path || path[0] == '\0')
{
return OK;
}
/* Then loop for each directory/file component in the full path */
entryname = path;
terminator = NULL;
for (; ; )
{
/* Find the start of the next path component */
while (*entryname == '/') entryname++;
/* Find the end of the next path component */
terminator = strchr(entryname, '/');
if (!terminator)
{
entrylen = strlen(entryname);
}
else
{
entrylen = terminator - entryname;
}
/* Long path segment names will be truncated to NAME_MAX */
if (entrylen > NAME_MAX)
{
entrylen = NAME_MAX;
}
/* Then find the entry in the current directory with the
* matching name.
*/
ret = romfs_searchdir(rm, entryname, entrylen, dirinfo);
if (ret < 0)
{
return ret;
}
/* Was that the last path component? */
if (!terminator)
{
/* Yes.. return success */
return OK;
}
/* No... If that was not the last path component, then it had
* better have been a directory
*/
if (!IS_DIRECTORY(dirinfo->rd_next))
{
return -ENOTDIR;
}
/* Setup to search the next directory for the next component
* of the path
*/
entryname = terminator;
}
return ERROR; /* Won't get here */
}
/****************************************************************************
* Name: romfs_parsedirentry
*
* Description:
* Return the directory entry at this offset. If rf is NULL, then the
* mount device resources are used. Otherwise, file resources are used.
*
****************************************************************************/
int romfs_parsedirentry(struct romfs_mountpt_s *rm, uint32_t offset,
uint32_t *poffset, uint32_t *pnext, uint32_t *pinfo,
uint32_t *psize)
{
uint32_t save;
uint32_t next;
int16_t ndx;
int ret;
/* Read the sector into memory */
ndx = romfs_devcacheread(rm, offset);
if (ndx < 0)
{
return ndx;
}
/* Yes.. Save the first 'next' value. That has the offset needed to
* traverse the parent directory. But we may need to change the type
* after we follow the hard links.
*/
save = romfs_devread32(rm, ndx + ROMFS_FHDR_NEXT);
/* Traverse hardlinks as necessary to get to the real file header */
ret = romfs_followhardlinks(rm, offset, poffset);
if (ret < 0)
{
return ret;
}
/* Because everything is chunked and aligned to 16-bit boundaries,
* we know that most the basic node info fits into the sector. The
* associated name may not, however.
*/
next = romfs_devread32(rm, ndx + ROMFS_FHDR_NEXT);
*pnext = (save & RFNEXT_OFFSETMASK) | (next & RFNEXT_ALLMODEMASK);
*pinfo = romfs_devread32(rm, ndx + ROMFS_FHDR_INFO);
*psize = romfs_devread32(rm, ndx + ROMFS_FHDR_SIZE);
return OK;
}
/****************************************************************************
* Name: romfs_parsefilename
*
* Description:
* Return the filename from directory entry at this offset
*
****************************************************************************/
int romfs_parsefilename(struct romfs_mountpt_s *rm, uint32_t offset,
char *pname)
{
int16_t ndx;
uint16_t namelen;
uint16_t chunklen;
bool done;
/* Loop until the whole name is obtained or until NAME_MAX characters
* of the name have been parsed.
*/
offset += ROMFS_FHDR_NAME;
for (namelen = 0, done = false; namelen < NAME_MAX && !done; )
{
/* Read the sector into memory */
ndx = romfs_devcacheread(rm, offset + namelen);
if (ndx < 0)
{
return ndx;
}
/* Is the name terminated in this 16-byte block */
if (rm->rm_buffer[ndx + 15] == '\0')
{
/* Yes.. then this chunk is less than 16 */
chunklen = strlen((FAR char *)&rm->rm_buffer[ndx]);
done = true;
}
else
{
/* No.. then this chunk is 16 bytes in length */
chunklen = 16;
}
/* Check if we would exceed the NAME_MAX */
if (namelen + chunklen > NAME_MAX)
{
chunklen = NAME_MAX - namelen;
done = true;
}
/* Copy the chunk */
memcpy(&pname[namelen], &rm->rm_buffer[ndx], chunklen);
namelen += chunklen;
}
/* Terminate the name (NAME_MAX+1 chars total) and return success */
pname[namelen] = '\0';
return OK;
}
/****************************************************************************
* Name: romfs_datastart
*
* Description:
* Given the offset to a file header, return the offset to the start of
* the file data
*
****************************************************************************/
int romfs_datastart(struct romfs_mountpt_s *rm, uint32_t offset,
uint32_t *start)
{
int16_t ndx;
int ret;
/* Traverse hardlinks as necessary to get to the real file header */
ret = romfs_followhardlinks(rm, offset, &offset);
if (ret < 0)
{
return ret;
}
/* Loop until the header size is obtained. */
offset += ROMFS_FHDR_NAME;
for (; ; )
{
/* Read the sector into memory */
ndx = romfs_devcacheread(rm, offset);
if (ndx < 0)
{
return ndx;
}
/* Get the offset to the next chunk */
offset += 16;
if (offset >= rm->rm_volsize)
{
return -EIO;
}
/* Is the name terminated in this 16-byte block */
if (rm->rm_buffer[ndx + 15] == '\0')
{
/* Yes.. then the data starts at the next chunk */
*start = offset;
return OK;
}
}
return -EINVAL; /* Won't get here */
}
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