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5e510557e5
nuttx/fs/romfs/fs_romfsutil.c
patacongo 5e510557e5 ROMFS filesystem 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@902 42af7a65-404d-4744-a932-0658087f49c3
2008-09-10 19:27:49 +00:00

776 lines
21 KiB
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/****************************************************************************
* rm/romfs/fs_romfsutil.h
*
* Copyright (C) 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include "fs_romfs.h"
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: romfs_swap32
*
* Desciption:
* Convert the 32-bit big endian value to little endian
*
****************************************************************************/
#ifndef CONFIG_ENDIAN_BIG
static inline uint32 romfs_swap32(uint32 value)
{
return ((((value) & 0x000000ff) << 24) | (((value) & 0x0000ff00) << 8) |
(((value) & 0x00ff0000) >> 8) | (((value) & 0xff000000) >> 24));
}
#endif
/****************************************************************************
* Name: romfs_devread32
*
* Desciption:
* Read the big-endian 32-bit value from the mount device buffer
*
* Assumption:
* All values are aligned to 32-bit boundaries
*
****************************************************************************/
static uint32 romfs_devread32(struct romfs_mountpt_s *rm, int ndx)
{
/* Extract the value */
uint32 value = *(uint32*)&rm->rm_buffer[ndx];
/* Value is begin endian -- return the native host endian-ness. */
#ifdef CONFIG_ENDIAN_BIG
return value;
#else
return romfs_swap32(value);
#endif
}
/****************************************************************************
* Name: romfs_checkentry
*
* Desciption:
* Check if the entry at offset is a directory or file path segment
*
****************************************************************************/
static inline int romfs_checkentry(struct romfs_mountpt_s *rm, uint32 offset,
const char *entryname, int entrylen,
struct romfs_dirinfo_s *dirinfo)
{
char name[NAME_MAX+1];
uint32 linkoffset;
uint32 next;
uint32 info;
uint32 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_diroffset = linkoffset;
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_searchdir
*
* Desciption:
* 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 offset;
uint32 sector;
uint32 next;
uint16 ndx;
int ret;
/* Then loop through the current directory until the directory
* with the matching name is found.
*/
offset = dirinfo->rd_dir.fr_firstoffset;
for (;;)
{
/* Convert the offset into sector + index */
sector = SEC_NSECTORS(rm, offset);
ndx = offset & SEC_NDXMASK(rm);
/* 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).
*/
ret = romfs_devcacheread(rm, sector);
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.
*/
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 directoy with that name */
return -ENOENT;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: romfs_semtake
****************************************************************************/
void romfs_semtake(struct romfs_mountpt_s *rm)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&rm->rm_sem) != 0)
{
/* The only case that an error should occur here is if
* the wait was awakened by a signal.
*/
ASSERT(*get_errno_ptr() == EINTR);
}
}
/****************************************************************************
* Name: romfs_semgive
****************************************************************************/
void romfs_semgive(struct romfs_mountpt_s *rm)
{
sem_post(&rm->rm_sem);
}
/****************************************************************************
* Name: romfs_hwread
*
* Desciption: Read the specified sector into the sector buffer
*
****************************************************************************/
int romfs_hwread(struct romfs_mountpt_s *rm, ubyte *buffer, uint32 sector,
unsigned int nsectors)
{
struct inode *inode;;
ssize_t nsectorsread;
int ret = -ENODEV;
if (rm && rm->rm_blkdriver)
{
inode = rm->rm_blkdriver;
if (inode && inode->u.i_bops && 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_devcacheread
*
* Desciption:
* Read the specified sector into the sector cache
*
****************************************************************************/
int romfs_devcacheread(struct romfs_mountpt_s *rm, uint32 sector)
{
int ret;
/* rm->rm_cachesector holds the current sector that is buffered in
* rm->tm_buffer. If the requested sector is the same as this sector, then
* we do nothing. Otherwise, we will have to read the new sector.
*/
if (rm->rm_cachesector != sector)
{
ret = romfs_hwread(rm, rm->rm_buffer, sector, 1);
if (ret < 0)
{
return ret;
}
/* Update the cached sector number */
rm->rm_cachesector = sector;
}
return OK;
}
/****************************************************************************
* Name: romfs_filecacheread
*
* Desciption:
* Read the specified sector into the sector cache
*
****************************************************************************/
int romfs_filecacheread(struct romfs_mountpt_s *rm, struct romfs_file_s *rf, uint32 sector)
{
int ret;
/* rf->rf_cachesector holds the current sector that is buffered in
* rf->rf_buffer. If the requested sector is the same as this sector, then
* we do nothing. Otherwise, we will have to read the new sector.
*/
if (rf->rf_cachesector != sector)
{
ret = romfs_hwread(rm, rf->rf_buffer, sector, 1);
if (ret < 0)
{
return ret;
}
/* Update the cached sector number */
rf->rf_cachesector = sector;
}
return OK;
}
/****************************************************************************
* Name: romfs_getgeometry
*
* Desciption:
* Get the geometry of the device (part of the mount operation)
*
****************************************************************************/
int romfs_getgeometry(struct romfs_mountpt_s *rm)
{
struct inode *inode = rm->rm_blkdriver;
struct geometry geo;
int ret;
/* Get the underlying device geometry */
if (!inode || !inode->u.i_bops || !inode->u.i_bops->geometry)
{
return -ENODEV;
}
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;
return OK;
}
/****************************************************************************
* Name: romfs_mount
*
* Desciption:
* Setup ROMFS on the block driver
*
****************************************************************************/
int romfs_mount(struct romfs_mountpt_s *rm)
{
const char *name;
int ret;
/* Then get information about the ROMFS filesystem on the devices managed
* by this block driver. Read sector zero which contains the volume header.
*/
ret = romfs_devcacheread(rm, 0);
if (ret != 0)
{
return ret;
}
/* 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 = (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_checkmount
*
* Desciption: Check if the mountpoint is still valid.
*
* The caller should hold the mountpoint semaphore
*
****************************************************************************/
int romfs_checkmount(struct romfs_mountpt_s *rm)
{
/* If the fs_mounted flag is FALSE, then we have already handled the loss
* of the mount.
*/
if (rm && rm->rm_mounted)
{
struct romfs_file_s *file;
/* We still think the mount is healthy. Check an see if this is
* still the case
*/
if (rm->rm_blkdriver)
{
struct inode *inode = rm->rm_blkdriver;
if (inode && inode->u.i_bops && inode->u.i_bops->geometry)
{
struct geometry geo;
int errcode = inode->u.i_bops->geometry(inode, &geo);
if (errcode == OK && geo.geo_available && !geo.geo_mediachanged)
{
return OK;
}
}
}
/* If we get here, the mount is NOT healthy */
rm->rm_mounted = FALSE;
/* Make sure that this is flagged in every opened file */
for (file = rm->rm_head; file; file = file->rf_next)
{
file->rf_open = FALSE;
}
}
return -ENODEV;
}
/****************************************************************************
* Name: romfs_finddirentry
*
* Desciption:
* 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_diroffset = 0;
dirinfo->rd_dir.fr_firstoffset = rm->rm_rootoffset;
dirinfo->rd_dir.fr_curroffset = rm->rm_rootoffset;
dirinfo->rd_next = 0;
dirinfo->rd_size = 0;
/* 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
*
* Desciption:
* 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 offset, uint32 *poffset,
uint32 *pnext, uint32 *pinfo, uint32 *psize)
{
uint32 sector;
uint32 save;
uint32 next;
uint32 info;
uint32 size;
uint16 ndx;
int ret;
int i;
/* Loop while we are redirected by hardlinks */
for (i = 0; i < ROMF_MAX_LINKS; i++)
{
/* Convert the offset into sector + index */
sector = SEC_NSECTORS(rm, offset);
ndx = offset & SEC_NDXMASK(rm);
/* Read the sector into memory */
ret = romfs_devcacheread(rm, sector);
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);
info = romfs_devread32(rm, ndx + ROMFS_FHDR_INFO);
size = romfs_devread32(rm, ndx + ROMFS_FHDR_SIZE);
/* Is this the first offset we have tried? */
if (i == 0)
{
/* Yes.. Save the first 'next' value. That has the offset needed to
* traverse the parent directory.
*/
save = next;
}
/* Is this a hardlink? */
if (IS_HARDLINK(next))
{
/* Yes.. then the info field is the offset to the actual entry
* that we are interested in.
*/
offset = info;
}
else
{
/* No... then break returning the directory information.
* Retaining the original offset
*/
*poffset = offset;
*pnext = (save & RFNEXT_OFFSETMASK) | (next & RFNEXT_MODEMASK);
*pinfo = info;
*psize = size;
return OK;
}
}
/* Too many hard links -- probably an infinite loop */
return -ELOOP;
}
/****************************************************************************
* Name: romfs_parsefilename
*
* Desciption:
* Return the filename from directory entry at this offset
*
****************************************************************************/
int romfs_parsefilename(struct romfs_mountpt_s *rm, uint32 offset, char *pname)
{
uint32 sector;
uint16 ndx;
uint16 namelen;
uint16 chunklen;
boolean done;
int ret;
/* 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;)
{
/* Convert the offset into sector + index */
sector = SEC_NSECTORS(rm, offset);
ndx = offset & SEC_NDXMASK(rm);
/* Read the sector into memory */
ret = romfs_devcacheread(rm, sector);
if (ret < 0)
{
return ret;
}
/* 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((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;
}
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