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+/* lfn.c - Functions for handling VFAT long filenames
+
+ Copyright (C) 1998 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
+ Copyright (C) 2008-2013 Daniel Baumann <mail@daniel-baumann.ch>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+ On Debian systems, the complete text of the GNU General Public License
+ can be found in /usr/share/common-licenses/GPL-3 file.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <time.h>
+
+#include "common.h"
+#include "io.h"
+#include "dosfsck.h"
+#include "lfn.h"
+#include "file.h"
+
+typedef struct {
+ __u8 id; /* sequence number for slot */
+ __u8 name0_4[10]; /* first 5 characters in name */
+ __u8 attr; /* attribute byte */
+ __u8 reserved; /* always 0 */
+ __u8 alias_checksum; /* checksum for 8.3 alias */
+ __u8 name5_10[12]; /* 6 more characters in name */
+ __u16 start; /* starting cluster number, 0 in long slots */
+ __u8 name11_12[4]; /* last 2 characters in name */
+} LFN_ENT;
+
+#define LFN_ID_START 0x40
+#define LFN_ID_SLOTMASK 0x1f
+
+#define CHARS_PER_LFN 13
+
+/* These modul-global vars represent the state of the LFN parser */
+unsigned char *lfn_unicode = NULL;
+unsigned char lfn_checksum;
+int lfn_slot = -1;
+loff_t *lfn_offsets = NULL;
+int lfn_parts = 0;
+
+static unsigned char fat_uni2esc[64] = {
+ '0', '1', '2', '3', '4', '5', '6', '7',
+ '8', '9', 'A', 'B', 'C', 'D', 'E', 'F',
+ 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
+ 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
+ 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
+ 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
+ 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
+ 'u', 'v', 'w', 'x', 'y', 'z', '+', '-'
+};
+
+/* This defines which unicode chars are directly convertable to ISO-8859-1 */
+#define UNICODE_CONVERTABLE(cl,ch) (ch == 0 && (cl < 0x80 || cl >= 0xa0))
+
+/* for maxlen param */
+#define UNTIL_0 INT_MAX
+
+/* Convert name part in 'lfn' from unicode to ASCII */
+#define CNV_THIS_PART(lfn) \
+ ({ \
+ unsigned char __part_uni[CHARS_PER_LFN*2]; \
+ copy_lfn_part( __part_uni, lfn ); \
+ cnv_unicode( __part_uni, CHARS_PER_LFN, 0 ); \
+ })
+
+/* Convert name parts collected so far (from previous slots) from unicode to
+ * ASCII */
+#define CNV_PARTS_SO_FAR() \
+ (cnv_unicode( lfn_unicode+(lfn_slot*CHARS_PER_LFN*2), \
+ lfn_parts*CHARS_PER_LFN, 0 ))
+
+#define BYTES_TO_WCHAR(cl,ch) ((wchar_t)((unsigned)(cl) + ((unsigned)(ch) << 8)))
+static size_t mbslen(wchar_t x)
+{
+ wchar_t wstr[] = { x, 0 };
+ return wcstombs(NULL, wstr, 0);
+}
+
+static size_t wctombs(char *dest, wchar_t x)
+{
+ wchar_t wstr[] = { x, 0 };
+ size_t size = wcstombs(NULL, wstr, 0);
+ if (size != (size_t) - 1)
+ size = wcstombs(dest, wstr, size + 1);
+ return size;
+}
+
+/* This function converts an unicode string to a normal ASCII string, assuming
+ * ISO-8859-1 charset. Characters not in 8859-1 are converted to the same
+ * escape notation as used by the kernel, i.e. the uuencode-like ":xxx" */
+static char *cnv_unicode(const unsigned char *uni, int maxlen, int use_q)
+{
+ const unsigned char *up;
+ unsigned char *out, *cp;
+ int len, val;
+ size_t x;
+
+ for (len = 0, up = uni; (up - uni) / 2 < maxlen && (up[0] || up[1]);
+ up += 2) {
+ if ((x = mbslen(BYTES_TO_WCHAR(up[0], up[1]))) != (size_t) - 1)
+ len += x;
+ else if (UNICODE_CONVERTABLE(up[0], up[1]))
+ ++len;
+ else
+ len += 4;
+ }
+ cp = out = use_q ? qalloc(&mem_queue, len + 1) : alloc(len + 1);
+
+ for (up = uni; (up - uni) / 2 < maxlen && (up[0] || up[1]); up += 2) {
+ if ((x = wctombs(cp, BYTES_TO_WCHAR(up[0], up[1]))) != (size_t) - 1)
+ cp += x;
+ else if (UNICODE_CONVERTABLE(up[0], up[1]))
+ *cp++ = up[0];
+ else {
+ /* here the same escape notation is used as in the Linux kernel */
+ *cp++ = ':';
+ val = (up[1] << 8) + up[0];
+ cp[2] = fat_uni2esc[val & 0x3f];
+ val >>= 6;
+ cp[1] = fat_uni2esc[val & 0x3f];
+ val >>= 6;
+ cp[0] = fat_uni2esc[val & 0x3f];
+ cp += 3;
+ }
+ }
+ *cp = 0;
+
+ return (char *)out;
+}
+
+static void copy_lfn_part(unsigned char *dst, LFN_ENT * lfn)
+{
+ memcpy(dst, lfn->name0_4, 10);
+ memcpy(dst + 10, lfn->name5_10, 12);
+ memcpy(dst + 22, lfn->name11_12, 4);
+}
+
+static void clear_lfn_slots(int start, int end)
+{
+ int i;
+ LFN_ENT empty;
+
+ /* New dir entry is zeroed except first byte, which is set to 0xe5.
+ * This is to avoid that some FAT-reading OSes (not Linux! ;) stop reading
+ * a directory at the first zero entry...
+ */
+ memset(&empty, 0, sizeof(empty));
+ empty.id = DELETED_FLAG;
+
+ for (i = start; i <= end; ++i) {
+ fs_write(lfn_offsets[i], sizeof(LFN_ENT), &empty);
+ }
+}
+
+void lfn_fix_checksum(loff_t from, loff_t to, const char *short_name)
+{
+ int i;
+ __u8 sum;
+ for (sum = 0, i = 0; i < 11; i++)
+ sum = (((sum & 1) << 7) | ((sum & 0xfe) >> 1)) + short_name[i];
+
+ for (; from < to; from += sizeof(LFN_ENT)) {
+ fs_write(from + offsetof(LFN_ENT, alias_checksum), sizeof(sum), &sum);
+ }
+}
+
+void lfn_reset(void)
+{
+ if (lfn_unicode)
+ free(lfn_unicode);
+ lfn_unicode = NULL;
+ if (lfn_offsets)
+ free(lfn_offsets);
+ lfn_offsets = NULL;
+ lfn_slot = -1;
+}
+
+/* This function is only called with de->attr == VFAT_LN_ATTR. It stores part
+ * of the long name. */
+void lfn_add_slot(DIR_ENT * de, loff_t dir_offset)
+{
+ LFN_ENT *lfn = (LFN_ENT *) de;
+ int slot = lfn->id & LFN_ID_SLOTMASK;
+ unsigned offset;
+
+ if (lfn_slot == 0)
+ lfn_check_orphaned();
+
+ if (de->attr != VFAT_LN_ATTR)
+ die("lfn_add_slot called with non-LFN directory entry");
+
+ if (lfn->id & LFN_ID_START && slot != 0) {
+ if (lfn_slot != -1) {
+ int can_clear = 0;
+ /* There is already a LFN "in progess", so it is an error that a
+ * new start entry is here. */
+ /* Causes: 1) if slot# == expected: start bit set mysteriously, 2)
+ * old LFN overwritten by new one */
+ /* Fixes: 1) delete previous LFN 2) if slot# == expected and
+ * checksum ok: clear start bit */
+ /* XXX: Should delay that until next LFN known (then can better
+ * display the name) */
+ printf("A new long file name starts within an old one.\n");
+ if (slot == lfn_slot && lfn->alias_checksum == lfn_checksum) {
+ char *part1 = CNV_THIS_PART(lfn);
+ char *part2 = CNV_PARTS_SO_FAR();
+ printf(" It could be that the LFN start bit is wrong here\n"
+ " if \"%s\" seems to match \"%s\".\n", part1, part2);
+ free(part1);
+ free(part2);
+ can_clear = 1;
+ }
+ if (interactive) {
+ printf("1: Delete previous LFN\n2: Leave it as it is.\n");
+ if (can_clear)
+ printf("3: Clear start bit and concatenate LFNs\n");
+ } else
+ printf(" Not auto-correcting this.\n");
+ if (interactive) {
+ switch (get_key(can_clear ? "123" : "12", "?")) {
+ case '1':
+ clear_lfn_slots(0, lfn_parts - 1);
+ lfn_reset();
+ break;
+ case '2':
+ break;
+ case '3':
+ lfn->id &= ~LFN_ID_START;
+ fs_write(dir_offset + offsetof(LFN_ENT, id),
+ sizeof(lfn->id), &lfn->id);
+ break;
+ }
+ }
+ }
+ lfn_slot = slot;
+ lfn_checksum = lfn->alias_checksum;
+ lfn_unicode = alloc((lfn_slot * CHARS_PER_LFN + 1) * 2);
+ lfn_offsets = alloc(lfn_slot * sizeof(loff_t));
+ lfn_parts = 0;
+ } else if (lfn_slot == -1 && slot != 0) {
+ /* No LFN in progress, but slot found; start bit missing */
+ /* Causes: 1) start bit got lost, 2) Previous slot with start bit got
+ * lost */
+ /* Fixes: 1) delete LFN, 2) set start bit */
+ char *part = CNV_THIS_PART(lfn);
+ printf("Long filename fragment \"%s\" found outside a LFN "
+ "sequence.\n (Maybe the start bit is missing on the "
+ "last fragment)\n", part);
+ if (interactive) {
+ printf("1: Delete fragment\n2: Leave it as it is.\n"
+ "3: Set start bit\n");
+ } else
+ printf(" Not auto-correcting this.\n");
+ switch (interactive ? get_key("123", "?") : '2') {
+ case '1':
+ if (!lfn_offsets)
+ lfn_offsets = alloc(sizeof(loff_t));
+ lfn_offsets[0] = dir_offset;
+ clear_lfn_slots(0, 0);
+ lfn_reset();
+ return;
+ case '2':
+ lfn_reset();
+ return;
+ case '3':
+ lfn->id |= LFN_ID_START;
+ fs_write(dir_offset + offsetof(LFN_ENT, id),
+ sizeof(lfn->id), &lfn->id);
+ lfn_slot = slot;
+ lfn_checksum = lfn->alias_checksum;
+ lfn_unicode = alloc((lfn_slot * CHARS_PER_LFN + 1) * 2);
+ lfn_offsets = alloc(lfn_slot * sizeof(loff_t));
+ lfn_parts = 0;
+ break;
+ }
+ } else if (slot != lfn_slot) {
+ /* wrong sequence number */
+ /* Causes: 1) seq-no destroyed */
+ /* Fixes: 1) delete LFN, 2) fix number (maybe only if following parts
+ * are ok?, maybe only if checksum is ok?) (Attention: space
+ * for name was allocated before!) */
+ int can_fix = 0;
+ printf("Unexpected long filename sequence number "
+ "(%d vs. expected %d).\n", slot, lfn_slot);
+ if (lfn->alias_checksum == lfn_checksum && lfn_slot > 0) {
+ char *part1 = CNV_THIS_PART(lfn);
+ char *part2 = CNV_PARTS_SO_FAR();
+ printf(" It could be that just the number is wrong\n"
+ " if \"%s\" seems to match \"%s\".\n", part1, part2);
+ free(part1);
+ free(part2);
+ can_fix = 1;
+ }
+ if (interactive) {
+ printf
+ ("1: Delete LFN\n2: Leave it as it is (and ignore LFN so far)\n");
+ if (can_fix)
+ printf("3: Correct sequence number\n");
+ } else
+ printf(" Not auto-correcting this.\n");
+ switch (interactive ? get_key(can_fix ? "123" : "12", "?") : '2') {
+ case '1':
+ if (!lfn_offsets) {
+ lfn_offsets = alloc(sizeof(loff_t));
+ lfn_parts = 0;
+ }
+ lfn_offsets[lfn_parts++] = dir_offset;
+ clear_lfn_slots(0, lfn_parts - 1);
+ lfn_reset();
+ return;
+ case '2':
+ lfn_reset();
+ return;
+ case '3':
+ lfn->id = (lfn->id & ~LFN_ID_SLOTMASK) | lfn_slot;
+ fs_write(dir_offset + offsetof(LFN_ENT, id),
+ sizeof(lfn->id), &lfn->id);
+ break;
+ }
+ }
+
+ if (lfn->alias_checksum != lfn_checksum) {
+ /* checksum mismatch */
+ /* Causes: 1) checksum field here destroyed */
+ /* Fixes: 1) delete LFN, 2) fix checksum */
+ printf("Checksum in long filename part wrong "
+ "(%02x vs. expected %02x).\n",
+ lfn->alias_checksum, lfn_checksum);
+ if (interactive) {
+ printf("1: Delete LFN\n2: Leave it as it is.\n"
+ "3: Correct checksum\n");
+ } else
+ printf(" Not auto-correcting this.\n");
+ if (interactive) {
+ switch (get_key("123", "?")) {
+ case '1':
+ lfn_offsets[lfn_parts++] = dir_offset;
+ clear_lfn_slots(0, lfn_parts - 1);
+ lfn_reset();
+ return;
+ case '2':
+ break;
+ case '3':
+ lfn->alias_checksum = lfn_checksum;
+ fs_write(dir_offset + offsetof(LFN_ENT, alias_checksum),
+ sizeof(lfn->alias_checksum), &lfn->alias_checksum);
+ break;
+ }
+ }
+ }
+
+ if (lfn_slot != -1) {
+ lfn_slot--;
+ offset = lfn_slot * CHARS_PER_LFN * 2;
+ copy_lfn_part(lfn_unicode + offset, lfn);
+ if (lfn->id & LFN_ID_START)
+ lfn_unicode[offset + 26] = lfn_unicode[offset + 27] = 0;
+ lfn_offsets[lfn_parts++] = dir_offset;
+ }
+
+ if (lfn->reserved != 0) {
+ printf("Reserved field in VFAT long filename slot is not 0 "
+ "(but 0x%02x).\n", lfn->reserved);
+ if (interactive)
+ printf("1: Fix.\n2: Leave it.\n");
+ else
+ printf("Auto-setting to 0.\n");
+ if (!interactive || get_key("12", "?") == '1') {
+ lfn->reserved = 0;
+ fs_write(dir_offset + offsetof(LFN_ENT, reserved),
+ sizeof(lfn->reserved), &lfn->reserved);
+ }
+ }
+ if (lfn->start != CT_LE_W(0)) {
+ printf("Start cluster field in VFAT long filename slot is not 0 "
+ "(but 0x%04x).\n", lfn->start);
+ if (interactive)
+ printf("1: Fix.\n2: Leave it.\n");
+ else
+ printf("Auto-setting to 0.\n");
+ if (!interactive || get_key("12", "?") == '1') {
+ lfn->start = CT_LE_W(0);
+ fs_write(dir_offset + offsetof(LFN_ENT, start),
+ sizeof(lfn->start), &lfn->start);
+ }
+ }
+}
+
+/* This function is always called when de->attr != VFAT_LN_ATTR is found, to
+ * retrieve the previously constructed LFN. */
+char *lfn_get(DIR_ENT * de, loff_t * lfn_offset)
+{
+ char *lfn;
+ __u8 sum;
+ int i;
+
+ *lfn_offset = 0;
+ if (de->attr == VFAT_LN_ATTR)
+ die("lfn_get called with LFN directory entry");
+
+#if 0
+ if (de->lcase)
+ printf("lcase=%02x\n", de->lcase);
+#endif
+
+ if (lfn_slot == -1)
+ /* no long name for this file */
+ return NULL;
+
+ if (lfn_slot != 0) {
+ /* The long name isn't finished yet. */
+ /* Causes: 1) LFN slot overwritten by non-VFAT aware tool */
+ /* Fixes: 1) delete LFN 2) move overwriting entry to somewhere else
+ * and let user enter missing part of LFN (hard to do :-()
+ * 3) renumber entries and truncate name */
+ char *long_name = CNV_PARTS_SO_FAR();
+ char *short_name = file_name(de->name);
+ printf("Unfinished long file name \"%s\".\n"
+ " (Start may have been overwritten by %s)\n",
+ long_name, short_name);
+ free(long_name);
+ if (interactive) {
+ printf("1: Delete LFN\n2: Leave it as it is.\n"
+ "3: Fix numbering (truncates long name and attaches "
+ "it to short name %s)\n", short_name);
+ } else
+ printf(" Not auto-correcting this.\n");
+ switch (interactive ? get_key("123", "?") : '2') {
+ case '1':
+ clear_lfn_slots(0, lfn_parts - 1);
+ lfn_reset();
+ return NULL;
+ case '2':
+ lfn_reset();
+ return NULL;
+ case '3':
+ for (i = 0; i < lfn_parts; ++i) {
+ __u8 id = (lfn_parts - i) | (i == 0 ? LFN_ID_START : 0);
+ fs_write(lfn_offsets[i] + offsetof(LFN_ENT, id),
+ sizeof(id), &id);
+ }
+ memmove(lfn_unicode, lfn_unicode + lfn_slot * CHARS_PER_LFN * 2,
+ lfn_parts * CHARS_PER_LFN * 2);
+ break;
+ }
+ }
+
+ for (sum = 0, i = 0; i < 11; i++)
+ sum = (((sum & 1) << 7) | ((sum & 0xfe) >> 1)) + de->name[i];
+ if (sum != lfn_checksum) {
+ /* checksum doesn't match, long name doesn't apply to this alias */
+ /* Causes: 1) alias renamed */
+ /* Fixes: 1) Fix checksum in LFN entries */
+ char *long_name = CNV_PARTS_SO_FAR();
+ char *short_name = file_name(de->name);
+ printf("Wrong checksum for long file name \"%s\".\n"
+ " (Short name %s may have changed without updating the long name)\n",
+ long_name, short_name);
+ free(long_name);
+ if (interactive) {
+ printf("1: Delete LFN\n2: Leave it as it is.\n"
+ "3: Fix checksum (attaches to short name %s)\n", short_name);
+ } else
+ printf(" Not auto-correcting this.\n");
+ if (interactive) {
+ switch (get_key("123", "?")) {
+ case '1':
+ clear_lfn_slots(0, lfn_parts - 1);
+ lfn_reset();
+ return NULL;
+ case '2':
+ lfn_reset();
+ return NULL;
+ case '3':
+ for (i = 0; i < lfn_parts; ++i) {
+ fs_write(lfn_offsets[i] + offsetof(LFN_ENT, alias_checksum),
+ sizeof(sum), &sum);
+ }
+ break;
+ }
+ }
+ }
+
+ *lfn_offset = lfn_offsets[0];
+ lfn = cnv_unicode(lfn_unicode, UNTIL_0, 1);
+ lfn_reset();
+ return (lfn);
+}
+
+void lfn_check_orphaned(void)
+{
+ char *long_name;
+
+ if (lfn_slot == -1)
+ return;
+
+ long_name = CNV_PARTS_SO_FAR();
+ printf("Orphaned long file name part \"%s\"\n", long_name);
+ if (interactive)
+ printf("1: Delete.\n2: Leave it.\n");
+ else
+ printf(" Auto-deleting.\n");
+ if (!interactive || get_key("12", "?") == '1') {
+ clear_lfn_slots(0, lfn_parts - 1);
+ }
+ lfn_reset();
+}
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