/* lfn.c  -  Functions for handling VFAT long filenames *//* Written 1998 by Roman Hodek */#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)				\    ({							\	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 ))/* 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;        for( len = 0, up = uni; (up-uni)/2 < maxlen && (up[0] || up[1]); up += 2 ){	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 (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( out );}static void copy_lfn_part( 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_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;    unsigned offset;    if (de->attr != VFAT_LN_ATTR)	die("lfn_add_slot called with non-LFN directory entry");    if (lfn->id & LFN_ID_START) {	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 ((lfn->id & LFN_ID_SLOTMASK) == 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 = lfn->id & LFN_ID_SLOTMASK;	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) {	/* 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" );	if (interactive) {	    switch( get_key( "123", "?" )) {	      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 = lfn->id & LFN_ID_SLOTMASK;		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 ((lfn->id & LFN_ID_SLOTMASK) != 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",		(lfn->id & LFN_ID_SLOTMASK), lfn_slot );	if (lfn->alias_checksum == lfn_checksum) {	    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" );	if (interactive) {	    switch( get_key( can_fix ? "123" : "12", "?" )) {	      case '1':		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;	    }	}    }        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 ){    char *lfn;    __u8 sum;    int i;        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" );	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 ) {		    __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 = cnv_unicode( lfn_unicode, UNTIL_0, 1 );    lfn_reset();    return( lfn );}/* Local Variables: *//* tab-width: 8     *//* End:             */