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nuttx/fs/romfs/fs_romfsutil.c
Jiuzhu Dong fe17f747a7 fs/directory: move private directory information to filesystem 
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
2022-08-09 23:30:01 +08:00

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/****************************************************************************
* fs/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 <inttypes.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/mtd/mtd.h>
#include "fs_romfs.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define LINK_NOT_FOLLOWED 0
#define LINK_FOLLOWED 1
#define NODEINFO_NINCR 4
/****************************************************************************
* Private Types
****************************************************************************/
struct romfs_entryname_s
{
FAR const char *re_name;
size_t re_len;
};
/****************************************************************************
* 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(FAR 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
*
****************************************************************************/
#ifndef CONFIG_FS_ROMFS_CACHE_NODE
static inline int romfs_checkentry(FAR struct romfs_mountpt_s *rm,
uint32_t offset,
FAR const char *entryname, int entrylen,
FAR struct romfs_nodeinfo_s *nodeinfo)
{
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;
}
/* 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 (strlen(name) == entrylen &&
memcmp(entryname, name, entrylen) == 0)
{
/* Found it -- save the component info and return success */
if (IS_DIRECTORY(next))
{
nodeinfo->rn_offset = info;
nodeinfo->rn_size = 0;
}
else
{
nodeinfo->rn_offset = linkoffset;
nodeinfo->rn_size = size;
}
nodeinfo->rn_next = next;
return OK;
}
/* The entry is not a directory or it does not have the matching name */
return -ENOENT;
}
#endif
/****************************************************************************
* 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
*
****************************************************************************/
static int16_t romfs_devcacheread(FAR 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->rm_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(FAR struct romfs_mountpt_s *rm,
uint32_t offset, FAR 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_nodeinfo_search/romfs_nodeinfo_compare
*
* Description:
* Compare two names
*
****************************************************************************/
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
static int romfs_nodeinfo_search(FAR const void *a, FAR const void *b)
{
FAR struct romfs_nodeinfo_s *nodeinfo = *(FAR struct romfs_nodeinfo_s **)b;
FAR const struct romfs_entryname_s *entry = a;
FAR const char *name2 = nodeinfo->rn_name;
size_t len = nodeinfo->rn_namesize;
int ret;
if (len > entry->re_len)
{
len = entry->re_len;
}
ret = strncmp(entry->re_name, name2, len);
if (!ret)
{
if (entry->re_name[len] == '/' || entry->re_name[len] == '\0')
{
return name2[len] == '\0' ? 0 : -1;
}
else
{
return 1;
}
}
return ret;
}
static int romfs_nodeinfo_compare(FAR const void *a, FAR const void *b)
{
FAR struct romfs_nodeinfo_s *nodeinfo = *(FAR struct romfs_nodeinfo_s **)a;
struct romfs_entryname_s entry;
entry.re_name = nodeinfo->rn_name;
entry.re_len = nodeinfo->rn_namesize;
return romfs_nodeinfo_search(&entry, b);
}
#endif
/****************************************************************************
* Name: romfs_searchdir
*
* Description:
* This is part of the romfs_finddirentry log. Search the directory
* beginning at nodeinfo->rn_offset for entryname.
*
****************************************************************************/
static inline int romfs_searchdir(FAR struct romfs_mountpt_s *rm,
FAR const char *entryname, int entrylen,
FAR struct romfs_nodeinfo_s *nodeinfo)
{
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
FAR struct romfs_nodeinfo_s **cnodeinfo;
struct romfs_entryname_s entry;
entry.re_name = entryname;
entry.re_len = entrylen;
cnodeinfo = bsearch(&entry, nodeinfo->rn_child, nodeinfo->rn_count,
sizeof(*nodeinfo->rn_child), romfs_nodeinfo_search);
if (cnodeinfo)
{
memcpy(nodeinfo, *cnodeinfo, sizeof(*nodeinfo));
return OK;
}
#else
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 = nodeinfo->rn_offset;
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, nodeinfo);
if (ret == OK)
{
/* Its a match! Return success */
return OK;
}
/* No match... select the offset to the next entry */
offset = next;
}
while (next != 0);
#endif
/* There is nothing in this directory with that name */
return -ENOENT;
}
/****************************************************************************
* Name: romfs_cachenode
*
* Description:
* Alloc all entry node at once when filesystem is mounted
*
****************************************************************************/
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
static int romfs_cachenode(FAR struct romfs_mountpt_s *rm,
uint32_t offset, uint32_t next,
uint32_t size, FAR const char *name,
FAR struct romfs_nodeinfo_s **pnodeinfo)
{
FAR struct romfs_nodeinfo_s **child;
FAR struct romfs_nodeinfo_s *nodeinfo;
char childname[NAME_MAX + 1];
uint32_t linkoffset;
uint32_t info;
uint8_t num = 0;
int ret;
nodeinfo = kmm_zalloc(sizeof(struct romfs_nodeinfo_s) + strlen(name));
if (nodeinfo == NULL)
{
return -ENOMEM;
}
*pnodeinfo = nodeinfo;
nodeinfo->rn_offset = offset;
nodeinfo->rn_next = next;
nodeinfo->rn_namesize = strlen(name);
strcpy(nodeinfo->rn_name, name);
if (!IS_DIRECTORY(next))
{
nodeinfo->rn_size = size;
return 0;
}
child = nodeinfo->rn_child;
do
{
/* 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;
}
ret = romfs_parsefilename(rm, offset, childname);
if (ret < 0)
{
return ret;
}
if (strcmp(childname, ".") != 0 && strcmp(childname, "..") != 0)
{
if (child == NULL || nodeinfo->rn_count == num - 1)
{
FAR void *tmp;
tmp = kmm_realloc(nodeinfo->rn_child, (num + NODEINFO_NINCR) *
sizeof(*nodeinfo->rn_child));
if (tmp == NULL)
{
return -ENOMEM;
}
nodeinfo->rn_child = tmp;
memset(nodeinfo->rn_child + num, 0, NODEINFO_NINCR *
sizeof(*nodeinfo->rn_child));
num += NODEINFO_NINCR;
}
child = &nodeinfo->rn_child[nodeinfo->rn_count++];
if (IS_DIRECTORY(next))
{
linkoffset = info;
}
ret = romfs_cachenode(rm, linkoffset, next, size,
childname, child);
if (ret < 0)
{
nodeinfo->rn_count--;
return ret;
}
}
next &= RFNEXT_OFFSETMASK;
offset = next;
}
while (next != 0);
if (nodeinfo->rn_count > 1)
{
qsort(nodeinfo->rn_child, nodeinfo->rn_count,
sizeof(*nodeinfo->rn_child), romfs_nodeinfo_compare);
}
return 0;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: romfs_semtake
****************************************************************************/
int romfs_semtake(FAR struct romfs_mountpt_s *rm)
{
return nxsem_wait_uninterruptible(&rm->rm_sem);
}
/****************************************************************************
* Name: romfs_semgive
****************************************************************************/
void romfs_semgive(FAR 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(FAR struct romfs_mountpt_s *rm, FAR 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 */
FAR 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(FAR struct romfs_mountpt_s *rm,
FAR struct romfs_file_s *rf, uint32_t sector)
{
int ret;
finfo("sector: %" PRId32 " cached: %" PRId32
" 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(FAR struct romfs_mountpt_s *rm)
{
FAR 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, BIOC_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 = 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(FAR struct romfs_mountpt_s *rm)
{
FAR 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];
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
ndx = romfs_cachenode(rm, ROMFS_ALIGNUP(ROMFS_VHDR_VOLNAME +
strlen(name) + 1),
RFNEXT_DIRECTORY, 0, "", &rm->rm_root);
if (ndx < 0)
{
romfs_freenode(rm->rm_root);
return ndx;
}
#else
rm->rm_rootoffset = ROMFS_ALIGNUP(ROMFS_VHDR_VOLNAME + strlen(name) + 1);
#endif
/* 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(FAR struct romfs_mountpt_s *rm,
FAR 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(FAR struct romfs_mountpt_s *rm)
{
FAR 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_freenode
*
* Description:
* free all entry node at once when filesystem is unmounted
*
****************************************************************************/
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
void romfs_freenode(FAR struct romfs_nodeinfo_s *nodeinfo)
{
int i;
if (IS_DIRECTORY(nodeinfo->rn_next))
{
for (i = 0; i < nodeinfo->rn_count; i++)
{
romfs_freenode(nodeinfo->rn_child[i]);
}
kmm_free(nodeinfo->rn_child);
}
kmm_free(nodeinfo);
}
#endif
/****************************************************************************
* 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(FAR struct romfs_mountpt_s *rm,
FAR struct romfs_nodeinfo_s *nodeinfo,
FAR const char *path)
{
FAR const char *entryname;
FAR const char *terminator;
int entrylen;
int ret;
/* Start with the first element after the root directory */
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
memcpy(nodeinfo, rm->rm_root, sizeof(*nodeinfo));
#else
nodeinfo->rn_offset = rm->rm_rootoffset;
nodeinfo->rn_next = RFNEXT_DIRECTORY;
nodeinfo->rn_size = 0;
#endif
/* 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, nodeinfo);
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(nodeinfo->rn_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(FAR struct romfs_mountpt_s *rm, uint32_t offset,
FAR uint32_t *poffset, uint32_t *pnext,
FAR uint32_t *pinfo, FAR 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(FAR struct romfs_mountpt_s *rm, uint32_t offset,
FAR 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(FAR struct romfs_mountpt_s *rm,
FAR struct romfs_nodeinfo_s *nodeinfo,
FAR uint32_t *start)
{
#ifdef CONFIG_FS_ROMFS_CACHE_NODE
*start = ROMFS_ALIGNUP(nodeinfo->rn_offset +
ROMFS_FHDR_NAME + nodeinfo->rn_namesize + 1);
return OK;
#else
uint32_t offset = nodeinfo->rn_offset;
int16_t ndx;
/* 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 */
#endif
}
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