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nuttx/fs/romfs/fs_romfsutil.c
Gregory Nutt 32e98790c0 Correct ROMFS hardlink handling 
This PR corrects an error in the ROMFS file system.  The error occurred after following a hard link (depending on how the ROMFS image is organized).  The error occurred because some of the information buffered before following the links was stale and, hence, out of sync after following the hard link.  This would cause random errors when paths containing hardlinks were used with ROMFS.

This PR resolves Issue #1543.  Please compare the following output with the output in Issue #1543 to see how the problem was resolved:

    NuttShell (NSH) NuttX-9.1.0
    nsh> mount
      /etc type romfs
      /proc type procfs
      /tmp type vfat
    nsh> ls -Rl /etc
    /etc:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      20 group
     dr-xr-xr-x       0 init.d/
     -r-xr-xr-x      35 passwd
    /etc/init.d:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      71 rcS

    nsh> ls -l /etc/init.d
    /etc/init.d:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      71 rcS
    nsh> ls -l /etc/init.d/.
    /etc/init.d/.:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      71 rcS

    nsh> ls -l /etc/init.d/..
    /etc/init.d/..:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      20 group
     dr-xr-xr-x       0 init.d/
     -r-xr-xr-x      35 passwd
    nsh> ls -l /etc/init.d/../.
    /etc/init.d/../.:
     dr-xr-xr-x       0 .
     dr-xr-xr-x       0 ..
     -r-xr-xr-x      20 group
     dr-xr-xr-x       0 init.d/
     -r-xr-xr-x      35 passwd
    nsh>
2020-08-10 07:32:06 -07:00

1001 lines
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/****************************************************************************
* rm/romfs/fs_romfsutil.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/* References: Linux/Documentation/filesystems/romfs.txt */
/****************************************************************************
* 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"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define LINK_NOT_FOLLOWED 0
#define LINK_FOLLOWED 1
/****************************************************************************
* 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)
{
/* This should not read past the end of the sector since the directory
* entries are aligned at 16-byte boundaries.
*/
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
* this 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.
*
* Return value:
* < 0 : An error occurred
* 0 : No link followed
* 1 : Link followed, poffset is the new volume offset
*
****************************************************************************/
static int romfs_followhardlinks(struct romfs_mountpt_s *rm, uint32_t offset,
uint32_t *poffset)
{
uint32_t next;
int16_t ndx;
int i;
int ret = LINK_NOT_FOLLOWED;
/* 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 ret;
}
/* Follow the hard-link. Set return to indicate that we followed a
* link and that poffset was set to the link offset is valid.
*/
offset = romfs_devread32(rm, ndx + ROMFS_FHDR_INFO);
ret = LINK_FOLLOWED;
}
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
****************************************************************************/
int romfs_semtake(struct romfs_mountpt_s *rm)
{
return 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
* include 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;
}
if (entrylen == 0)
{
return OK;
}
/* 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;
}
else if (ret > 0)
{
/* The link was followed */
ndx = romfs_devcacheread(rm, *poffset);
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. The
* associated name may not, however.
*
* NOTE: Since ROMFS directory entries are aligned to 16-byte boundaries,
* we are assured that ndx + ROMFS_FHDR_INFO/SIZE will lie wholly within
* the sector buffer.
*/
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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