u-boot/fs/fat/fat_write.c
Heinrich Schuchardt 3ecc5277f4 fs: fat: remove trailing periods from long name
The FAT32 File System Specification [1] requires leading and trailing
spaces as well as trailing periods of long names to be ignored.

[1]
    Microsoft Extensible Firmware Initiative
    FAT32 File System Specification
    Version 1.03, December 6, 2000
    Microsoft Corporation
    https://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2021-02-03 11:41:02 +01:00

1773 lines
38 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* fat_write.c
*
* R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
*/
#include <common.h>
#include <command.h>
#include <config.h>
#include <div64.h>
#include <fat.h>
#include <log.h>
#include <malloc.h>
#include <part.h>
#include <rand.h>
#include <asm/byteorder.h>
#include <asm/cache.h>
#include <linux/ctype.h>
#include <linux/math64.h>
#include "fat.c"
static dir_entry *find_directory_entry(fat_itr *itr, char *filename);
static int new_dir_table(fat_itr *itr);
/* Characters that may only be used in long file names */
static const char LONG_ONLY_CHARS[] = "+,;=[]";
/* Combined size of the name and ext fields in the directory entry */
#define SHORT_NAME_SIZE 11
/**
* str2fat() - convert string to valid FAT name characters
*
* Stop when reaching end of @src or a period.
* Ignore spaces.
* Replace characters that may only be used in long names by underscores.
* Convert lower case characters to upper case.
*
* To avoid assumptions about the code page we do not use characters
* above 0x7f for the short name.
*
* @dest: destination buffer
* @src: source buffer
* @length: size of destination buffer
* Return: number of bytes in destination buffer
*/
static int str2fat(char *dest, char *src, int length)
{
int i;
for (i = 0; i < length; ++src) {
char c = *src;
if (!c || c == '.')
break;
if (c == ' ')
continue;
if (strchr(LONG_ONLY_CHARS, c) || c > 0x7f)
c = '_';
else if (c >= 'a' && c <= 'z')
c &= 0xdf;
dest[i] = c;
++i;
}
return i;
}
/**
* fat_move_to_cluster() - position to first directory entry in cluster
*
* @itr: directory iterator
* @cluster cluster
* Return: 0 for success, -EIO on error
*/
static int fat_move_to_cluster(fat_itr *itr, unsigned int cluster)
{
unsigned int nbytes;
/* position to the start of the directory */
itr->next_clust = cluster;
itr->last_cluster = 0;
if (!fat_next_cluster(itr, &nbytes))
return -EIO;
itr->dent = (dir_entry *)itr->block;
itr->remaining = nbytes / sizeof(dir_entry) - 1;
return 0;
}
/**
* set_name() - set short name in directory entry
*
* The function determines if the @filename is a valid short name.
* In this case no long name is needed.
*
* If a long name is needed, a short name is constructed.
*
* @itr: directory iterator
* @filename: long file name
* @shortname: buffer of 11 bytes to receive chosen short name and extension
* Return: number of directory entries needed, negative on error
*/
static int set_name(fat_itr *itr, const char *filename, char *shortname)
{
char *period;
char *pos;
int period_location;
char buf[13];
int i;
int ret;
struct nameext dirent;
if (!filename)
return -EIO;
/* Initialize buffer */
memset(&dirent, ' ', sizeof(dirent));
/* Convert filename to upper case short name */
period = strrchr(filename, '.');
pos = (char *)filename;
if (*pos == '.') {
pos = period + 1;
period = 0;
}
if (period)
str2fat(dirent.ext, period + 1, sizeof(dirent.ext));
period_location = str2fat(dirent.name, pos, sizeof(dirent.name));
if (period_location < 0)
return period_location;
if (*dirent.name == ' ')
*dirent.name = '_';
/* 0xe5 signals a deleted directory entry. Replace it by 0x05. */
if (*dirent.name == 0xe5)
*dirent.name = 0x05;
/* If filename and short name are the same, quit. */
sprintf(buf, "%.*s.%.3s", period_location, dirent.name, dirent.ext);
if (!strcmp(buf, filename)) {
ret = 1;
goto out;
}
/* Construct an indexed short name */
for (i = 1; i < 0x200000; ++i) {
int suffix_len;
int suffix_start;
int j;
/* To speed up the search use random numbers */
if (i < 10) {
j = i;
} else {
j = 30 - fls(i);
j = 10 + (rand() >> j);
}
sprintf(buf, "~%d", j);
suffix_len = strlen(buf);
suffix_start = 8 - suffix_len;
if (suffix_start > period_location)
suffix_start = period_location;
memcpy(dirent.name + suffix_start, buf, suffix_len);
if (*dirent.ext != ' ')
sprintf(buf, "%.*s.%.3s", suffix_start + suffix_len,
dirent.name, dirent.ext);
else
sprintf(buf, "%.*s", suffix_start + suffix_len,
dirent.name);
debug("generated short name: %s\n", buf);
/* Check that the short name does not exist yet. */
ret = fat_move_to_cluster(itr, itr->start_clust);
if (ret)
return ret;
if (find_directory_entry(itr, buf))
continue;
debug("chosen short name: %s\n", buf);
/* Each long name directory entry takes 13 characters. */
ret = (strlen(filename) + 25) / 13;
goto out;
}
return -EIO;
out:
memcpy(shortname, &dirent, SHORT_NAME_SIZE);
return ret;
}
static int total_sector;
static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
{
ulong ret;
if (!cur_dev)
return -1;
if (cur_part_info.start + block + nr_blocks >
cur_part_info.start + total_sector) {
printf("error: overflow occurs\n");
return -1;
}
ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
if (nr_blocks && ret == 0)
return -1;
return ret;
}
/*
* Write fat buffer into block device
*/
static int flush_dirty_fat_buffer(fsdata *mydata)
{
int getsize = FATBUFBLOCKS;
__u32 fatlength = mydata->fatlength;
__u8 *bufptr = mydata->fatbuf;
__u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
(int)mydata->fat_dirty);
if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
return 0;
/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
startblock += mydata->fat_sect;
/* Write FAT buf */
if (disk_write(startblock, getsize, bufptr) < 0) {
debug("error: writing FAT blocks\n");
return -1;
}
if (mydata->fats == 2) {
/* Update corresponding second FAT blocks */
startblock += mydata->fatlength;
if (disk_write(startblock, getsize, bufptr) < 0) {
debug("error: writing second FAT blocks\n");
return -1;
}
}
mydata->fat_dirty = 0;
return 0;
}
/**
* fat_find_empty_dentries() - find a sequence of available directory entries
*
* @itr: directory iterator
* @count: number of directory entries to find
* Return: 0 on success or negative error number
*/
static int fat_find_empty_dentries(fat_itr *itr, int count)
{
unsigned int cluster;
dir_entry *dent;
int remaining;
unsigned int n = 0;
int ret;
ret = fat_move_to_cluster(itr, itr->start_clust);
if (ret)
return ret;
for (;;) {
if (!itr->dent) {
log_debug("Not enough directory entries available\n");
return -ENOSPC;
}
switch (itr->dent->nameext.name[0]) {
case 0x00:
case DELETED_FLAG:
if (!n) {
/* Remember first deleted directory entry */
cluster = itr->clust;
dent = itr->dent;
remaining = itr->remaining;
}
++n;
if (n == count)
goto out;
break;
default:
n = 0;
break;
}
next_dent(itr);
if (!itr->dent &&
(!itr->is_root || itr->fsdata->fatsize == 32) &&
new_dir_table(itr))
return -ENOSPC;
}
out:
/* Position back to first directory entry */
if (itr->clust != cluster) {
ret = fat_move_to_cluster(itr, cluster);
if (ret)
return ret;
}
itr->dent = dent;
itr->remaining = remaining;
return 0;
}
/*
* Set the file name information from 'name' into 'slotptr',
*/
static int str2slot(dir_slot *slotptr, const char *name, int *idx)
{
int j, end_idx = 0;
for (j = 0; j <= 8; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name0_4[j] = 0;
slotptr->name0_4[j + 1] = 0;
end_idx++;
goto name0_4;
}
slotptr->name0_4[j] = name[*idx];
(*idx)++;
end_idx++;
}
for (j = 0; j <= 10; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name5_10[j] = 0;
slotptr->name5_10[j + 1] = 0;
end_idx++;
goto name5_10;
}
slotptr->name5_10[j] = name[*idx];
(*idx)++;
end_idx++;
}
for (j = 0; j <= 2; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name11_12[j] = 0;
slotptr->name11_12[j + 1] = 0;
end_idx++;
goto name11_12;
}
slotptr->name11_12[j] = name[*idx];
(*idx)++;
end_idx++;
}
if (name[*idx] == 0x00)
return 1;
return 0;
/* Not used characters are filled with 0xff 0xff */
name0_4:
for (; end_idx < 5; end_idx++) {
slotptr->name0_4[end_idx * 2] = 0xff;
slotptr->name0_4[end_idx * 2 + 1] = 0xff;
}
end_idx = 5;
name5_10:
end_idx -= 5;
for (; end_idx < 6; end_idx++) {
slotptr->name5_10[end_idx * 2] = 0xff;
slotptr->name5_10[end_idx * 2 + 1] = 0xff;
}
end_idx = 11;
name11_12:
end_idx -= 11;
for (; end_idx < 2; end_idx++) {
slotptr->name11_12[end_idx * 2] = 0xff;
slotptr->name11_12[end_idx * 2 + 1] = 0xff;
}
return 1;
}
static int flush_dir(fat_itr *itr);
/**
* fill_dir_slot() - fill directory entries for long name
*
* @itr: directory iterator
* @l_name: long name
* @shortname: short name
* Return: 0 for success, -errno otherwise
*/
static int
fill_dir_slot(fat_itr *itr, const char *l_name, const char *shortname)
{
__u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
__u8 counter = 0, checksum;
int idx = 0, ret;
/* Get short file name checksum value */
checksum = mkcksum((void *)shortname);
do {
memset(slotptr, 0x00, sizeof(dir_slot));
ret = str2slot(slotptr, l_name, &idx);
slotptr->id = ++counter;
slotptr->attr = ATTR_VFAT;
slotptr->alias_checksum = checksum;
slotptr++;
} while (ret == 0);
slotptr--;
slotptr->id |= LAST_LONG_ENTRY_MASK;
while (counter >= 1) {
memcpy(itr->dent, slotptr, sizeof(dir_slot));
slotptr--;
counter--;
if (!itr->remaining) {
/* Write directory table to device */
ret = flush_dir(itr);
if (ret)
return ret;
}
next_dent(itr);
if (!itr->dent)
return -EIO;
}
return 0;
}
/*
* Set the entry at index 'entry' in a FAT (12/16/32) table.
*/
static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
{
__u32 bufnum, offset, off16;
__u16 val1, val2;
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
offset = entry - bufnum * FAT32BUFSIZE;
break;
case 16:
bufnum = entry / FAT16BUFSIZE;
offset = entry - bufnum * FAT16BUFSIZE;
break;
case 12:
bufnum = entry / FAT12BUFSIZE;
offset = entry - bufnum * FAT12BUFSIZE;
break;
default:
/* Unsupported FAT size */
return -1;
}
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
int getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
startblock += mydata->fat_sect;
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return -1;
}
mydata->fatbufnum = bufnum;
}
/* Mark as dirty */
mydata->fat_dirty = 1;
/* Set the actual entry */
switch (mydata->fatsize) {
case 32:
((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
break;
case 16:
((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
break;
case 12:
off16 = (offset * 3) / 4;
switch (offset & 0x3) {
case 0:
val1 = cpu_to_le16(entry_value) & 0xfff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
((__u16 *)mydata->fatbuf)[off16] |= val1;
break;
case 1:
val1 = cpu_to_le16(entry_value) & 0xf;
val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
break;
case 2:
val1 = cpu_to_le16(entry_value) & 0xff;
val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
break;
case 3:
val1 = cpu_to_le16(entry_value) & 0xfff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
break;
default:
break;
}
break;
default:
return -1;
}
return 0;
}
/*
* Determine the next free cluster after 'entry' in a FAT (12/16/32) table
* and link it to 'entry'. EOC marker is not set on returned entry.
*/
static __u32 determine_fatent(fsdata *mydata, __u32 entry)
{
__u32 next_fat, next_entry = entry + 1;
while (1) {
next_fat = get_fatent(mydata, next_entry);
if (next_fat == 0) {
/* found free entry, link to entry */
set_fatent_value(mydata, entry, next_entry);
break;
}
next_entry++;
}
debug("FAT%d: entry: %08x, entry_value: %04x\n",
mydata->fatsize, entry, next_entry);
return next_entry;
}
/**
* set_sectors() - write data to sectors
*
* Write 'size' bytes from 'buffer' into the specified sector.
*
* @mydata: data to be written
* @startsect: sector to be written to
* @buffer: data to be written
* @size: bytes to be written (but not more than the size of a cluster)
* Return: 0 on success, -1 otherwise
*/
static int
set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
{
int ret;
debug("startsect: %d\n", startsect);
if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
debug("FAT: Misaligned buffer address (%p)\n", buffer);
while (size >= mydata->sect_size) {
memcpy(tmpbuf, buffer, mydata->sect_size);
ret = disk_write(startsect++, 1, tmpbuf);
if (ret != 1) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
buffer += mydata->sect_size;
size -= mydata->sect_size;
}
} else if (size >= mydata->sect_size) {
u32 nsects;
nsects = size / mydata->sect_size;
ret = disk_write(startsect, nsects, buffer);
if (ret != nsects) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
startsect += nsects;
buffer += nsects * mydata->sect_size;
size -= nsects * mydata->sect_size;
}
if (size) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
/* Do not leak content of stack */
memset(tmpbuf, 0, mydata->sect_size);
memcpy(tmpbuf, buffer, size);
ret = disk_write(startsect, 1, tmpbuf);
if (ret != 1) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
}
return 0;
}
/**
* set_cluster() - write data to cluster
*
* Write 'size' bytes from 'buffer' into the specified cluster.
*
* @mydata: data to be written
* @clustnum: cluster to be written to
* @buffer: data to be written
* @size: bytes to be written (but not more than the size of a cluster)
* Return: 0 on success, -1 otherwise
*/
static int
set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
{
return set_sectors(mydata, clust_to_sect(mydata, clustnum),
buffer, size);
}
/**
* flush_dir() - flush directory
*
* @itr: directory iterator
* Return: 0 for success, -EIO on error
*/
static int flush_dir(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
u32 startsect, sect_offset, nsects;
int ret;
if (!itr->is_root || mydata->fatsize == 32) {
ret = set_cluster(mydata, itr->clust, itr->block,
mydata->clust_size * mydata->sect_size);
goto out;
}
sect_offset = itr->clust * mydata->clust_size;
startsect = mydata->rootdir_sect + sect_offset;
/* do not write past the end of rootdir */
nsects = min_t(u32, mydata->clust_size,
mydata->rootdir_size - sect_offset);
ret = set_sectors(mydata, startsect, itr->block,
nsects * mydata->sect_size);
out:
if (ret) {
log_err("Error: writing directory entry\n");
return -EIO;
}
return 0;
}
/*
* Read and modify data on existing and consecutive cluster blocks
*/
static int
get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
loff_t size, loff_t *gotsize)
{
static u8 *tmpbuf_cluster;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 startsect;
loff_t wsize;
int clustcount, i, ret;
*gotsize = 0;
if (!size)
return 0;
if (!tmpbuf_cluster) {
tmpbuf_cluster = memalign(ARCH_DMA_MINALIGN, MAX_CLUSTSIZE);
if (!tmpbuf_cluster)
return -1;
}
assert(pos < bytesperclust);
startsect = clust_to_sect(mydata, clustnum);
debug("clustnum: %d, startsect: %d, pos: %lld\n",
clustnum, startsect, pos);
/* partial write at beginning */
if (pos) {
wsize = min(bytesperclust - pos, size);
ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(tmpbuf_cluster + pos, buffer, wsize);
ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
buffer += wsize;
*gotsize += wsize;
startsect += mydata->clust_size;
if (!size)
return 0;
}
/* full-cluster write */
if (size >= bytesperclust) {
clustcount = lldiv(size, bytesperclust);
if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
wsize = clustcount * bytesperclust;
ret = disk_write(startsect,
clustcount * mydata->clust_size,
buffer);
if (ret != clustcount * mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
buffer += wsize;
*gotsize += wsize;
startsect += clustcount * mydata->clust_size;
} else {
for (i = 0; i < clustcount; i++) {
memcpy(tmpbuf_cluster, buffer, bytesperclust);
ret = disk_write(startsect,
mydata->clust_size,
tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n",
ret);
return -1;
}
size -= bytesperclust;
buffer += bytesperclust;
*gotsize += bytesperclust;
startsect += mydata->clust_size;
}
}
}
/* partial write at end */
if (size) {
wsize = size;
ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(tmpbuf_cluster, buffer, wsize);
ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
*gotsize += wsize;
}
assert(!size);
return 0;
}
/*
* Find the first empty cluster
*/
static int find_empty_cluster(fsdata *mydata)
{
__u32 fat_val, entry = 3;
while (1) {
fat_val = get_fatent(mydata, entry);
if (fat_val == 0)
break;
entry++;
}
return entry;
}
/**
* new_dir_table() - allocate a cluster for additional directory entries
*
* @itr: directory iterator
* Return: 0 on success, -EIO otherwise
*/
static int new_dir_table(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
int dir_newclust = 0;
int dir_oldclust = itr->clust;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
dir_newclust = find_empty_cluster(mydata);
/*
* Flush before updating FAT to ensure valid directory structure
* in case of failure.
*/
itr->clust = dir_newclust;
itr->next_clust = dir_newclust;
memset(itr->block, 0x00, bytesperclust);
if (flush_dir(itr))
return -EIO;
set_fatent_value(mydata, dir_oldclust, dir_newclust);
if (mydata->fatsize == 32)
set_fatent_value(mydata, dir_newclust, 0xffffff8);
else if (mydata->fatsize == 16)
set_fatent_value(mydata, dir_newclust, 0xfff8);
else if (mydata->fatsize == 12)
set_fatent_value(mydata, dir_newclust, 0xff8);
if (flush_dirty_fat_buffer(mydata) < 0)
return -EIO;
itr->dent = (dir_entry *)itr->block;
itr->last_cluster = 1;
itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
return 0;
}
/*
* Set empty cluster from 'entry' to the end of a file
*/
static int clear_fatent(fsdata *mydata, __u32 entry)
{
__u32 fat_val;
while (!CHECK_CLUST(entry, mydata->fatsize)) {
fat_val = get_fatent(mydata, entry);
if (fat_val != 0)
set_fatent_value(mydata, entry, 0);
else
break;
entry = fat_val;
}
/* Flush fat buffer */
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
return 0;
}
/*
* Set start cluster in directory entry
*/
static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
__u32 start_cluster)
{
if (mydata->fatsize == 32)
dentptr->starthi =
cpu_to_le16((start_cluster & 0xffff0000) >> 16);
dentptr->start = cpu_to_le16(start_cluster & 0xffff);
}
/*
* Check whether adding a file makes the file system to
* exceed the size of the block device
* Return -1 when overflow occurs, otherwise return 0
*/
static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
{
__u32 startsect, sect_num, offset;
if (clustnum > 0)
startsect = clust_to_sect(mydata, clustnum);
else
startsect = mydata->rootdir_sect;
sect_num = div_u64_rem(size, mydata->sect_size, &offset);
if (offset != 0)
sect_num++;
if (startsect + sect_num > total_sector)
return -1;
return 0;
}
/*
* Write at most 'maxsize' bytes from 'buffer' into
* the file associated with 'dentptr'
* Update the number of bytes written in *gotsize and return 0
* or return -1 on fatal errors.
*/
static int
set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
loff_t maxsize, loff_t *gotsize)
{
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 curclust = START(dentptr);
__u32 endclust = 0, newclust = 0;
u64 cur_pos, filesize;
loff_t offset, actsize, wsize;
*gotsize = 0;
filesize = pos + maxsize;
debug("%llu bytes\n", filesize);
if (!filesize) {
if (!curclust)
return 0;
if (!CHECK_CLUST(curclust, mydata->fatsize) ||
IS_LAST_CLUST(curclust, mydata->fatsize)) {
clear_fatent(mydata, curclust);
set_start_cluster(mydata, dentptr, 0);
return 0;
}
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
if (!curclust) {
assert(pos == 0);
goto set_clusters;
}
/* go to cluster at pos */
cur_pos = bytesperclust;
while (1) {
if (pos <= cur_pos)
break;
if (IS_LAST_CLUST(curclust, mydata->fatsize))
break;
newclust = get_fatent(mydata, curclust);
if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
cur_pos += bytesperclust;
curclust = newclust;
}
if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
assert(pos == cur_pos);
goto set_clusters;
}
assert(pos < cur_pos);
cur_pos -= bytesperclust;
/* overwrite */
assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
!CHECK_CLUST(curclust, mydata->fatsize));
while (1) {
/* search for allocated consecutive clusters */
actsize = bytesperclust;
endclust = curclust;
while (1) {
if (filesize <= (cur_pos + actsize))
break;
newclust = get_fatent(mydata, endclust);
if (newclust != endclust + 1)
break;
if (IS_LAST_CLUST(newclust, mydata->fatsize))
break;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
actsize += bytesperclust;
endclust = newclust;
}
/* overwrite to <curclust..endclust> */
if (pos < cur_pos)
offset = 0;
else
offset = pos - cur_pos;
wsize = min_t(unsigned long long, actsize, filesize - cur_pos);
wsize -= offset;
if (get_set_cluster(mydata, curclust, offset,
buffer, wsize, &actsize)) {
printf("Error get-and-setting cluster\n");
return -1;
}
buffer += wsize;
*gotsize += wsize;
cur_pos += offset + wsize;
if (filesize <= cur_pos)
break;
if (IS_LAST_CLUST(newclust, mydata->fatsize))
/* no more clusters */
break;
curclust = newclust;
}
if (filesize <= cur_pos) {
/* no more write */
newclust = get_fatent(mydata, endclust);
if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
/* truncate the rest */
clear_fatent(mydata, newclust);
/* Mark end of file in FAT */
if (mydata->fatsize == 12)
newclust = 0xfff;
else if (mydata->fatsize == 16)
newclust = 0xffff;
else if (mydata->fatsize == 32)
newclust = 0xfffffff;
set_fatent_value(mydata, endclust, newclust);
}
return 0;
}
curclust = endclust;
filesize -= cur_pos;
assert(!do_div(cur_pos, bytesperclust));
set_clusters:
/* allocate and write */
assert(!pos);
/* Assure that curclust is valid */
if (!curclust) {
curclust = find_empty_cluster(mydata);
set_start_cluster(mydata, dentptr, curclust);
} else {
newclust = get_fatent(mydata, curclust);
if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
newclust = determine_fatent(mydata, curclust);
set_fatent_value(mydata, curclust, newclust);
curclust = newclust;
} else {
debug("error: something wrong\n");
return -1;
}
}
/* TODO: already partially written */
if (check_overflow(mydata, curclust, filesize)) {
printf("Error: no space left: %llu\n", filesize);
return -1;
}
actsize = bytesperclust;
endclust = curclust;
do {
/* search for consecutive clusters */
while (actsize < filesize) {
newclust = determine_fatent(mydata, endclust);
if ((newclust - 1) != endclust)
/* write to <curclust..endclust> */
goto getit;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("newclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
endclust = newclust;
actsize += bytesperclust;
}
/* set remaining bytes */
actsize = filesize;
if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
*gotsize += actsize;
/* Mark end of file in FAT */
if (mydata->fatsize == 12)
newclust = 0xfff;
else if (mydata->fatsize == 16)
newclust = 0xffff;
else if (mydata->fatsize == 32)
newclust = 0xfffffff;
set_fatent_value(mydata, endclust, newclust);
return 0;
getit:
if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
*gotsize += actsize;
filesize -= actsize;
buffer += actsize;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("newclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
actsize = bytesperclust;
curclust = endclust = newclust;
} while (1);
return 0;
}
/**
* fill_dentry() - fill directory entry with shortname
*
* @mydata: private filesystem parameters
* @dentptr: directory entry
* @shortname: chosen short name
* @start_cluster: first cluster of file
* @size: file size
* @attr: file attributes
*/
static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
const char *shortname, __u32 start_cluster, __u32 size, __u8 attr)
{
memset(dentptr, 0, sizeof(*dentptr));
set_start_cluster(mydata, dentptr, start_cluster);
dentptr->size = cpu_to_le32(size);
dentptr->attr = attr;
memcpy(&dentptr->nameext, shortname, SHORT_NAME_SIZE);
}
/**
* find_directory_entry() - find a directory entry by filename
*
* @itr: directory iterator
* @filename: name of file to find
* Return: directory entry or NULL
*/
static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
{
int match = 0;
while (fat_itr_next(itr)) {
/* check both long and short name: */
if (!strcasecmp(filename, itr->name))
match = 1;
else if (itr->name != itr->s_name &&
!strcasecmp(filename, itr->s_name))
match = 1;
if (!match)
continue;
if (itr->dent->nameext.name[0] == '\0')
return NULL;
else
return itr->dent;
}
return NULL;
}
static int split_filename(char *filename, char **dirname, char **basename)
{
char *p, *last_slash, *last_slash_cont;
again:
p = filename;
last_slash = NULL;
last_slash_cont = NULL;
while (*p) {
if (ISDIRDELIM(*p)) {
last_slash = p;
last_slash_cont = p;
/* continuous slashes */
while (ISDIRDELIM(*p))
last_slash_cont = p++;
if (!*p)
break;
}
p++;
}
if (last_slash) {
if (last_slash_cont == (filename + strlen(filename) - 1)) {
/* remove trailing slashes */
*last_slash = '\0';
goto again;
}
if (last_slash == filename) {
/* avoid ""(null) directory */
*dirname = "/";
} else {
*last_slash = '\0';
*dirname = filename;
}
*last_slash_cont = '\0';
filename = last_slash_cont + 1;
} else {
*dirname = "/"; /* root by default */
}
/*
* The FAT32 File System Specification v1.03 requires leading and
* trailing spaces as well as trailing periods to be ignored.
*/
for (; *filename == ' '; ++filename)
;
/* Keep special entries '.' and '..' */
if (filename[0] == '.' &&
(!filename[1] || (filename[1] == '.' && !filename[2])))
goto done;
/* Remove trailing periods and spaces */
for (p = filename + strlen(filename) - 1; p >= filename; --p) {
switch (*p) {
case ' ':
case '.':
*p = 0;
break;
default:
goto done;
}
}
done:
*basename = filename;
return 0;
}
/**
* normalize_longname() - check long file name and convert to lower case
*
* We assume here that the FAT file system is using an 8bit code page.
* Linux typically uses CP437, EDK2 assumes CP1250.
*
* @l_filename: preallocated buffer receiving the normalized name
* @filename: filename to normalize
* Return: 0 on success, -1 on failure
*/
static int normalize_longname(char *l_filename, const char *filename)
{
const char *p, illegal[] = "<>:\"/\\|?*";
size_t len;
len = strlen(filename);
if (!len || len >= VFAT_MAXLEN_BYTES || filename[len - 1] == '.')
return -1;
for (p = filename; *p; ++p) {
if ((unsigned char)*p < 0x20)
return -1;
if (strchr(illegal, *p))
return -1;
}
strcpy(l_filename, filename);
downcase(l_filename, VFAT_MAXLEN_BYTES);
return 0;
}
int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
loff_t size, loff_t *actwrite)
{
dir_entry *retdent;
fsdata datablock = { .fatbuf = NULL, };
fsdata *mydata = &datablock;
fat_itr *itr = NULL;
int ret = -1;
char *filename_copy, *parent, *basename;
char l_filename[VFAT_MAXLEN_BYTES];
debug("writing %s\n", filename);
filename_copy = strdup(filename);
if (!filename_copy)
return -ENOMEM;
split_filename(filename_copy, &parent, &basename);
if (!strlen(basename)) {
ret = -EINVAL;
goto exit;
}
if (normalize_longname(l_filename, basename)) {
printf("FAT: illegal filename (%s)\n", basename);
ret = -EINVAL;
goto exit;
}
itr = malloc_cache_aligned(sizeof(fat_itr));
if (!itr) {
ret = -ENOMEM;
goto exit;
}
ret = fat_itr_root(itr, &datablock);
if (ret)
goto exit;
total_sector = datablock.total_sect;
ret = fat_itr_resolve(itr, parent, TYPE_DIR);
if (ret) {
printf("%s: doesn't exist (%d)\n", parent, ret);
goto exit;
}
retdent = find_directory_entry(itr, l_filename);
if (retdent) {
if (fat_itr_isdir(itr)) {
ret = -EISDIR;
goto exit;
}
/* A file exists */
if (pos == -1)
/* Append to the end */
pos = FAT2CPU32(retdent->size);
if (pos > retdent->size) {
/* No hole allowed */
ret = -EINVAL;
goto exit;
}
/* Update file size in a directory entry */
retdent->size = cpu_to_le32(pos + size);
} else {
/* Create a new file */
char shortname[SHORT_NAME_SIZE];
int ndent;
if (pos) {
/* No hole allowed */
ret = -EINVAL;
goto exit;
}
/* Check if long name is needed */
ndent = set_name(itr, basename, shortname);
if (ndent < 0) {
ret = ndent;
goto exit;
}
ret = fat_find_empty_dentries(itr, ndent);
if (ret)
goto exit;
if (ndent > 1) {
/* Set long name entries */
ret = fill_dir_slot(itr, basename, shortname);
if (ret)
goto exit;
}
/* Set short name entry */
fill_dentry(itr->fsdata, itr->dent, shortname, 0, size,
ATTR_ARCH);
retdent = itr->dent;
}
ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
if (ret < 0) {
printf("Error: writing contents\n");
ret = -EIO;
goto exit;
}
debug("attempt to write 0x%llx bytes\n", *actwrite);
/* Flush fat buffer */
ret = flush_dirty_fat_buffer(mydata);
if (ret) {
printf("Error: flush fat buffer\n");
ret = -EIO;
goto exit;
}
/* Write directory table to device */
ret = flush_dir(itr);
exit:
free(filename_copy);
free(mydata->fatbuf);
free(itr);
return ret;
}
int file_fat_write(const char *filename, void *buffer, loff_t offset,
loff_t maxsize, loff_t *actwrite)
{
return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
}
static int fat_dir_entries(fat_itr *itr)
{
fat_itr *dirs;
fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
/* for FATBUFSIZE */
int count;
dirs = malloc_cache_aligned(sizeof(fat_itr));
if (!dirs) {
debug("Error: allocating memory\n");
count = -ENOMEM;
goto exit;
}
/* duplicate fsdata */
fat_itr_child(dirs, itr);
fsdata = *dirs->fsdata;
/* allocate local fat buffer */
fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
if (!fsdata.fatbuf) {
debug("Error: allocating memory\n");
count = -ENOMEM;
goto exit;
}
fsdata.fatbufnum = -1;
dirs->fsdata = &fsdata;
for (count = 0; fat_itr_next(dirs); count++)
;
exit:
free(fsdata.fatbuf);
free(dirs);
return count;
}
/**
* delete_single_dentry() - delete a single directory entry
*
* @itr: directory iterator
* Return: 0 for success
*/
static int delete_single_dentry(fat_itr *itr)
{
struct dir_entry *dent = itr->dent;
memset(dent, 0, sizeof(*dent));
dent->nameext.name[0] = DELETED_FLAG;
if (!itr->remaining)
return flush_dir(itr);
return 0;
}
/**
* delete_long_name() - delete long name directory entries
*
* @itr: directory iterator
* Return: 0 for success
*/
static int delete_long_name(fat_itr *itr)
{
int seqn = itr->dent->nameext.name[0] & ~LAST_LONG_ENTRY_MASK;
while (seqn--) {
struct dir_entry *dent;
int ret;
ret = delete_single_dentry(itr);
if (ret)
return ret;
dent = next_dent(itr);
if (!dent)
return -EIO;
}
return 0;
}
/**
* delete_dentry_long() - remove directory entry
*
* @itr: directory iterator
* Return: 0 for success
*/
static int delete_dentry_long(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
dir_entry *dent = itr->dent;
/* free cluster blocks */
clear_fatent(mydata, START(dent));
if (flush_dirty_fat_buffer(mydata) < 0) {
printf("Error: flush fat buffer\n");
return -EIO;
}
/* Position to first directory entry for long name */
if (itr->clust != itr->dent_clust) {
int ret;
ret = fat_move_to_cluster(itr, itr->dent_clust);
if (ret)
return ret;
}
itr->dent = itr->dent_start;
itr->remaining = itr->dent_rem;
dent = itr->dent_start;
/* Delete long name */
if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
(dent->nameext.name[0] & LAST_LONG_ENTRY_MASK)) {
int ret;
ret = delete_long_name(itr);
if (ret)
return ret;
}
/* Delete short name */
delete_single_dentry(itr);
return flush_dir(itr);
}
int fat_unlink(const char *filename)
{
fsdata fsdata = { .fatbuf = NULL, };
fat_itr *itr = NULL;
int n_entries, ret;
char *filename_copy, *dirname, *basename;
filename_copy = strdup(filename);
if (!filename_copy) {
printf("Error: allocating memory\n");
ret = -ENOMEM;
goto exit;
}
split_filename(filename_copy, &dirname, &basename);
if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
printf("Error: cannot remove root\n");
ret = -EINVAL;
goto exit;
}
itr = malloc_cache_aligned(sizeof(fat_itr));
if (!itr) {
printf("Error: allocating memory\n");
ret = -ENOMEM;
goto exit;
}
ret = fat_itr_root(itr, &fsdata);
if (ret)
goto exit;
total_sector = fsdata.total_sect;
ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
if (ret) {
printf("%s: doesn't exist (%d)\n", dirname, ret);
ret = -ENOENT;
goto exit;
}
if (!find_directory_entry(itr, basename)) {
printf("%s: doesn't exist\n", basename);
ret = -ENOENT;
goto exit;
}
if (fat_itr_isdir(itr)) {
n_entries = fat_dir_entries(itr);
if (n_entries < 0) {
ret = n_entries;
goto exit;
}
if (n_entries > 2) {
printf("Error: directory is not empty: %d\n",
n_entries);
ret = -EINVAL;
goto exit;
}
}
ret = delete_dentry_long(itr);
exit:
free(fsdata.fatbuf);
free(itr);
free(filename_copy);
return ret;
}
int fat_mkdir(const char *dirname)
{
dir_entry *retdent;
fsdata datablock = { .fatbuf = NULL, };
fsdata *mydata = &datablock;
fat_itr *itr = NULL;
char *dirname_copy, *parent, *basename;
char l_dirname[VFAT_MAXLEN_BYTES];
int ret = -1;
loff_t actwrite;
unsigned int bytesperclust;
dir_entry *dotdent = NULL;
dirname_copy = strdup(dirname);
if (!dirname_copy)
goto exit;
split_filename(dirname_copy, &parent, &basename);
if (!strlen(basename)) {
ret = -EINVAL;
goto exit;
}
if (normalize_longname(l_dirname, basename)) {
printf("FAT: illegal filename (%s)\n", basename);
ret = -EINVAL;
goto exit;
}
itr = malloc_cache_aligned(sizeof(fat_itr));
if (!itr) {
ret = -ENOMEM;
goto exit;
}
ret = fat_itr_root(itr, &datablock);
if (ret)
goto exit;
total_sector = datablock.total_sect;
ret = fat_itr_resolve(itr, parent, TYPE_DIR);
if (ret) {
printf("%s: doesn't exist (%d)\n", parent, ret);
goto exit;
}
retdent = find_directory_entry(itr, l_dirname);
if (retdent) {
printf("%s: already exists\n", l_dirname);
ret = -EEXIST;
goto exit;
} else {
char shortname[SHORT_NAME_SIZE];
int ndent;
if (itr->is_root) {
/* root dir cannot have "." or ".." */
if (!strcmp(l_dirname, ".") ||
!strcmp(l_dirname, "..")) {
ret = -EINVAL;
goto exit;
}
}
/* Check if long name is needed */
ndent = set_name(itr, basename, shortname);
if (ndent < 0) {
ret = ndent;
goto exit;
}
ret = fat_find_empty_dentries(itr, ndent);
if (ret)
goto exit;
if (ndent > 1) {
/* Set long name entries */
ret = fill_dir_slot(itr, basename, shortname);
if (ret)
goto exit;
}
/* Set attribute as archive for regular file */
fill_dentry(itr->fsdata, itr->dent, shortname, 0, 0,
ATTR_DIR | ATTR_ARCH);
retdent = itr->dent;
}
/* Default entries */
bytesperclust = mydata->clust_size * mydata->sect_size;
dotdent = malloc_cache_aligned(bytesperclust);
if (!dotdent) {
ret = -ENOMEM;
goto exit;
}
memset(dotdent, 0, bytesperclust);
memcpy(&dotdent[0].nameext, ". ", 11);
dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
memcpy(&dotdent[1].nameext, ".. ", 11);
dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
if (itr->is_root)
set_start_cluster(mydata, &dotdent[1], 0);
else
set_start_cluster(mydata, &dotdent[1], itr->start_clust);
ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
bytesperclust, &actwrite);
if (ret < 0) {
printf("Error: writing contents\n");
goto exit;
}
/* Write twice for "." */
set_start_cluster(mydata, &dotdent[0], START(retdent));
ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
bytesperclust, &actwrite);
if (ret < 0) {
printf("Error: writing contents\n");
goto exit;
}
/* Flush fat buffer */
ret = flush_dirty_fat_buffer(mydata);
if (ret) {
printf("Error: flush fat buffer\n");
ret = -EIO;
goto exit;
}
/* Write directory table to device */
ret = flush_dir(itr);
exit:
free(dirname_copy);
free(mydata->fatbuf);
free(itr);
free(dotdent);
return ret;
}