fs: fat: create correct short names
The current function set_name() used to create short names has the
following deficiencies resolved by this patch:
* Long names (e.g. FOO.TXT) are stored even if a short name is enough.
* Short names with spaces are created, e.g. "A ~1.TXT".
* Short names with illegal characters are created, e.g. "FOO++BAR".
* Debug output does not not consider that the short file name has no
concluding '\0'.
The solution for the following bug is split of into a separate patch:
* Short file names must be unique.
This patch only provides the loop over possible short file names.
Fixes: c30a15e590 ("FAT: Add FAT write feature")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt
parent
d236e825a2
commit
28cef9ca2e
@ -8,25 +8,140 @@
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#include <common.h>
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#include <command.h>
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#include <config.h>
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#include <div64.h>
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#include <fat.h>
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#include <log.h>
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#include <malloc.h>
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#include <asm/byteorder.h>
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#include <part.h>
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#include <rand.h>
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#include <asm/byteorder.h>
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#include <asm/cache.h>
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#include <linux/ctype.h>
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#include <div64.h>
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#include <linux/math64.h>
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#include "fat.c"
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static void uppercase(char *str, int len)
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/* Characters that may only be used in long file names */
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static const char LONG_ONLY_CHARS[] = "+,;=[]";
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/**
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* str2fat() - convert string to valid FAT name characters
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*
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* Stop when reaching end of @src or a period.
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* Ignore spaces.
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* Replace characters that may only be used in long names by underscores.
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* Convert lower case characters to upper case.
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*
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* To avoid assumptions about the code page we do not use characters
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* above 0x7f for the short name.
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*
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* @dest: destination buffer
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* @src: source buffer
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* @length: size of destination buffer
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* Return: number of bytes in destination buffer
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*/
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static int str2fat(char *dest, char *src, int length)
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{
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int i;
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for (i = 0; i < len; i++) {
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*str = toupper(*str);
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str++;
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for (i = 0; i < length; ++src) {
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char c = *src;
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if (!c || c == '.')
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break;
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if (c == ' ')
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continue;
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if (strchr(LONG_ONLY_CHARS, c) || c > 0x7f)
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c = '_';
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else if (c >= 'a' && c <= 'z')
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c &= 0xdf;
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dest[i] = c;
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++i;
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}
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return i;
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}
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/**
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* set_name() - set short name in directory entry
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*
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* The function determines if the @filename is a valid short name.
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* In this case no long name is needed.
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*
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* If a long name is needed, a short name is constructed.
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*
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* @dirent: directory entry
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* @filename: long file name
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* Return: number of directory entries needed, negative on error
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*/
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static int set_name(dir_entry *dirent, const char *filename)
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{
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char *period;
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char *pos;
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int period_location;
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char buf[13];
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int i;
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if (!filename)
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return -EIO;
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/* Initialize buffers */
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memset(dirent->name, ' ', sizeof(dirent->name));
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memset(dirent->ext, ' ', sizeof(dirent->ext));
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/* Convert filename to upper case short name */
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period = strrchr(filename, '.');
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pos = (char *)filename;
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if (*pos == '.') {
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pos = period + 1;
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period = 0;
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}
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if (period)
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str2fat(dirent->ext, period + 1, sizeof(dirent->ext));
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period_location = str2fat(dirent->name, pos, sizeof(dirent->name));
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if (period_location < 0)
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return period_location;
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if (*dirent->name == ' ')
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*dirent->name = '_';
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/* 0xe5 signals a deleted directory entry. Replace it by 0x05. */
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if (*dirent->name == 0xe5)
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*dirent->name = 0x05;
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/* If filename and short name are the same, quit. */
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sprintf(buf, "%.*s.%.3s", period_location, dirent->name, dirent->ext);
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if (!strcmp(buf, filename))
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return 1;
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/* Construct an indexed short name */
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for (i = 1; i < 0x200000; ++i) {
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int suffix_len;
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int suffix_start;
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int j;
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/* To speed up the search use random numbers */
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if (i < 10) {
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j = i;
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} else {
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j = 30 - fls(i);
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j = 10 + (rand() >> j);
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}
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sprintf(buf, "~%d", j);
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suffix_len = strlen(buf);
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suffix_start = 8 - suffix_len;
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if (suffix_start > period_location)
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suffix_start = period_location;
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memcpy(dirent->name + suffix_start, buf, suffix_len);
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if (*dirent->ext != ' ')
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sprintf(buf, "%.*s.%.3s", suffix_start + suffix_len,
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dirent->name, dirent->ext);
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else
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sprintf(buf, "%.*s", suffix_start + suffix_len,
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dirent->name);
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debug("short name: %s\n", buf);
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/* TODO: Check that the short name does not exist yet. */
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/* Each long name directory entry takes 13 characters. */
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return (strlen(filename) + 25) / 13;
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}
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return -EIO;
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}
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static int total_sector;
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@ -50,67 +165,6 @@ static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
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return ret;
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}
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/**
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* set_name() - set short name in directory entry
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*
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* @dirent: directory entry
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* @filename: long file name
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*/
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static void set_name(dir_entry *dirent, const char *filename)
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{
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char s_name[VFAT_MAXLEN_BYTES];
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char *period;
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int period_location, len, i, ext_num;
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if (filename == NULL)
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return;
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len = strlen(filename);
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if (len == 0)
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return;
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strncpy(s_name, filename, VFAT_MAXLEN_BYTES - 1);
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s_name[VFAT_MAXLEN_BYTES - 1] = '\0';
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uppercase(s_name, len);
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period = strchr(s_name, '.');
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if (period == NULL) {
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period_location = len;
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ext_num = 0;
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} else {
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period_location = period - s_name;
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ext_num = len - period_location - 1;
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}
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/* Pad spaces when the length of file name is shorter than eight */
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if (period_location < 8) {
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memcpy(dirent->name, s_name, period_location);
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for (i = period_location; i < 8; i++)
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dirent->name[i] = ' ';
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} else if (period_location == 8) {
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memcpy(dirent->name, s_name, period_location);
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} else {
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memcpy(dirent->name, s_name, 6);
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/*
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* TODO: Translating two long names with the same first six
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* characters to the same short name is utterly wrong.
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* Short names must be unique.
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*/
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dirent->name[6] = '~';
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dirent->name[7] = '1';
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}
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if (ext_num < 3) {
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memcpy(dirent->ext, s_name + period_location + 1, ext_num);
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for (i = ext_num; i < 3; i++)
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dirent->ext[i] = ' ';
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} else
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memcpy(dirent->ext, s_name + period_location + 1, 3);
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debug("name : %s\n", dirent->name);
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debug("ext : %s\n", dirent->ext);
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}
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/*
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* Write fat buffer into block device
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*/
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@ -1181,13 +1235,15 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
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memset(itr->dent, 0, sizeof(*itr->dent));
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/* Calculate checksum for short name */
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set_name(itr->dent, filename);
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/* Set long name entries */
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if (fill_dir_slot(itr, filename)) {
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ret = -EIO;
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/* Check if long name is needed */
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ret = set_name(itr->dent, filename);
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if (ret < 0)
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goto exit;
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if (ret > 1) {
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/* Set long name entries */
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ret = fill_dir_slot(itr, filename);
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if (ret)
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goto exit;
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}
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/* Set short name entry */
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@ -1441,9 +1497,16 @@ int fat_mkdir(const char *new_dirname)
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memset(itr->dent, 0, sizeof(*itr->dent));
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/* Set short name to set alias checksum field in dir_slot */
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set_name(itr->dent, dirname);
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fill_dir_slot(itr, dirname);
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/* Check if long name is needed */
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ret = set_name(itr->dent, dirname);
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if (ret < 0)
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goto exit;
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if (ret > 1) {
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/* Set long name entries */
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ret = fill_dir_slot(itr, dirname);
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if (ret)
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goto exit;
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}
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/* Set attribute as archive for regular file */
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fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
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@ -168,7 +168,7 @@ config REGEX
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choice
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prompt "Pseudo-random library support type"
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depends on NET_RANDOM_ETHADDR || RANDOM_UUID || CMD_UUID || \
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RNG_SANDBOX || UT_LIB && AES
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RNG_SANDBOX || UT_LIB && AES || FAT_WRITE
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default LIB_RAND
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help
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Select the library to provide pseudo-random number generator
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