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source: soft/giet_vm/giet_fat32/fat32.c @ 341

Last change on this file since 341 was 337, checked in by alain, 10 years ago
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[258]	1	//////////////////////////////////////////////////////////////////////////////////
	2	// File : fat32.c
	3	// Date : 01/09/2013
	4	// Authors : Marco Jankovic, Cesar Fuguet & Alain Greiner
	5	// Copyright (c) UPMC-LIP6
	6	//////////////////////////////////////////////////////////////////////////////////
	7	// The fat32.h and fat32.c files define a library of access functions
[300]	8	// to a FAT32 disk on a block device. It is intended to be used
[258]	9	// by the GIET_VM nano-kernel for both the boot code and the kernel code.
	10	// This code uses functions defined in the utils.c and drivers.c files.
	11	//////////////////////////////////////////////////////////////////////////////////
	12	// Implementation notes:
	13	// 1. the "lba" (Logical Block Address) is the physical sector index on
	14	// the block device. The physical sector size is supposed to be 512 bytes.
	15	// 2. the "cluster" variable is actually a cluster index. A cluster contains
	16	// typically 8 sectors (4K bytes) and the cluster index is a 32 bits word.
	17	// 2. This FAT32 library uses a FAT cache whose storage capacity is one
	18	// sector (512 bytes, or 128 cluster indexes in FAT)
[295]	19	// 3. This FAT32 library can be used in four modes: BOOT_PA/BOOT_VA/KERNEL/USER
	20	// defining different behaviours for the IOC driver.
[258]	21	//////////////////////////////////////////////////////////////////////////////////
	22
	23	#include <giet_config.h>
	24	#include <fat32.h>
	25	#include <tty_driver.h>
	26	#include <ioc_driver.h>
	27	#include <utils.h>
	28
	29	//////////////////////////////////////////////////////////////////////////////////
	30	// Global variable used by all FAT access functions
	31	//////////////////////////////////////////////////////////////////////////////////
	32
	33	__attribute__((section (".kdata")))
	34	fat32_fs_t fat __attribute__((aligned(64)));
	35
	36	//////////////////////////////////////////////////////////////////////////////////
	37	// This function displays the content of the FAT cache
	38	//////////////////////////////////////////////////////////////////////////////////
	39	#if GIET_DEBUG_FAT
	40	void display_fat_cache()
	41	{
	42	unsigned int line;
	43	unsigned int word;
	44	unsigned int temp[9];
	45
	46	temp[8] = 0;
	47
[295]	48	_printf("\n********************* fat_cache_lba = %x ***************************\n",
	49	fat.cache_lba );
[258]	50
	51	for ( line=0 ; line<16 ; line++ )
	52	{
	53	// display address
[295]	54	_printf( "%x : ", (fat.cache_lba<<9) + (line<<5) );
[258]	55
	56	// display data hexa
	57	for ( word=0 ; word<8 ; word++ )
	58	{
	59	unsigned int byte = (line<<5) + (word<<2);
	60	unsigned int hexa = (fat.fat_cache[byte ]<<24) \|
	61	(fat.fat_cache[byte+1]<<16) \|
	62	(fat.fat_cache[byte+2]<< 8) \|
	63	(fat.fat_cache[byte+3]);
[295]	64	_printf("%x \| ", hexa );
[258]	65
	66	// prepare display ascii
	67	temp[word] = fat.fat_cache[byte] \|
	68	(fat.fat_cache[byte+1]<<8) \|
	69	(fat.fat_cache[byte+2]<<16) \|
	70	(fat.fat_cache[byte+3]<<24) ;
	71	}
	72
	73	// display data ascii
[295]	74	_printf( (char*)temp );
	75	_printf("\n");
[258]	76	}
[295]	77	_printf("**************************************************************************\n");
[258]	78	} // end display_fat_cache()
	79	#endif
[291]	80
[258]	81	//////////////////////////////////////////////////////////////////////////////////
	82	// This function returns the length of a FAT field. This field is identified
	83	// man by an (offset,length) mnemonic defined in fat32.h file.
	84	//////////////////////////////////////////////////////////////////////////////////
	85	static inline int get_length( int offset,
	86	int length)
	87	{
	88	return length;
	89	}
	90
	91	//////////////////////////////////////////////////////////////////////////////
[291]	92	// Write one 32 bits word "value" in a char[] buffer.
	93	// This field is defined by the offset and size arguments.
	94	//////////////////////////////////////////////////////////////////////////////
	95	static void write_entry( unsigned int offset,
	96	unsigned int size,
	97	char* buffer,
	98	unsigned int value )
	99	{
	100	unsigned int turn = 0;
	101	unsigned int res = value;
	102	unsigned int mask = 0x000000ff;
	103
	104	while( turn != size - 1 )
	105	{
	106	buffer[ offset + turn ] = res & mask;
	107	res = res >> 8;
	108	turn++;
	109	}
	110	buffer[offset + turn] = res & mask;
	111	}
	112
	113	//////////////////////////////////////////////////////////////////////////////
[258]	114	// Read one 32 bits word in a char[] buffer, taking endianness into account.
	115	// This field is defined by the offset and size arguments.
	116	//////////////////////////////////////////////////////////////////////////////
	117	static unsigned int read_entry( unsigned int offset,
	118	unsigned int size,
	119	char* buffer,
	120	unsigned int little_indian )
	121	{
	122	unsigned int turn;
	123	unsigned int res = 0;
	124	unsigned int mask = 0x000000ff;
	125
	126	if( little_indian )
	127	{
	128	turn = size;
	129	while( turn != 1 )
	130	{
	131	res = res \| (buffer[offset + (turn-1)] & mask);
	132	res = res << 8;
	133	turn--;
	134	}
	135	res = (buffer[offset + (turn-1)] & mask) \| res;
	136	}
	137	else
	138	{
	139	turn = 0;
	140	while( turn != size - 1 )
	141	{
	142
	143	res = res \| (buffer[ offset + turn ] & mask );
	144	res = res << 8;
	145	turn++;
	146	}
	147	res = res \| (buffer[offset + turn] & mask);
	148	}
	149	return res;
	150	}
	151
	152	//////////////////////////////////////////////////////////////////////////////////
	153	// This function retuns the cluster index from the lba of a DATA sector.
	154	// The lba must be larger than the lba of the first DATA sector.
	155	// The DATA region indexing starts a cluster 2.
	156	//////////////////////////////////////////////////////////////////////////////////
	157	static inline unsigned int lba_to_cluster( unsigned int lba )
	158	{
	159	if (lba < fat.data_lba ) return 0;
	160
	161	return ( (lba - fat.data_lba) / fat.sectors_per_cluster) + 2;
	162	}
	163
	164	//////////////////////////////////////////////////////////////////////////////////
	165	// This function retuns the lba of first sector in DATA region
	166	// from the cluster index. The cluster index must be larger than 2.
	167	//////////////////////////////////////////////////////////////////////////////////
	168	static inline unsigned int cluster_to_lba( unsigned int cluster )
	169	{
	170	if ( cluster < 2 ) return 0;
	171
	172	return (fat.sectors_per_cluster * (cluster - 2)) + fat.data_lba;
	173	}
	174
	175	/////////////////////////////////////////////////////////////////////////////////
	176	// This function search the FAT (using the FAT cache), and returns
[300]	177	// the next cluster index from the current cluster index in the FAT.
[258]	178	// remark: a sector of FAT contains 128 cluster indexes.
	179	/////////////////////////////////////////////////////////////////////////////////
	180	static unsigned int get_next_cluster_id( unsigned int mode,
	181	unsigned int cluster )
	182	{
	183	// compute lba of the sector containing the cluster index
[300]	184	unsigned int lba = fat.fat_lba + (cluster / 128);
[258]	185
	186	if ( lba == fat.cache_lba ) // hit in cache
	187	{
	188	return read_entry( ((cluster % 128) * 4),
	189	4,
	190	fat.fat_cache,
	191	1 );
	192	}
	193	else // miss in cache
	194	{
	195	// we cannot access fat in user mode
	196	if( mode == IOC_USER_MODE ) mode = IOC_KERNEL_MODE;
	197
	198	// access fat
[295]	199	if( _ioc_read( 0, // channel
	200	mode, // mode for IOC driver
[258]	201	lba, // sector index
	202	fat.fat_cache, // fat cache
	203	1 ) ) // one sector
	204	{
[295]	205	_printf("[FAT_ERROR] in get_next cluster_id() "
	206	"cannot read block %x\n", lba );
[258]	207	return 1;
	208	}
	209	fat.cache_lba = lba;
	210
	211	return read_entry( ((cluster % 128) * 4),
	212	4,
	213	fat.fat_cache,
	214	1 );
	215	}
	216	}
	217
	218	//////////////////////////////////////////////////////
	219	static inline unsigned char to_upper(unsigned char c)
	220	{
	221	if (c >= 'a' && c <= 'z') return (c & ~(0x20));
	222	else return c;
	223	}
	224
	225	////////////////////////////////////////////////////////////////
	226	// This function is a filter:
	227	// Return the c character if c is a legal short name character
	228	// Return the '_' character if c is illegal
	229	////////////////////////////////////////////////////////////////
	230	static unsigned char illegal_short(unsigned char c)
	231	{
	232	const unsigned char illegal_char [] =";+=[]â,\"*\\<>/?:\|\0";
	233	short i = 0;
	234	while (illegal_char[i]!='\0')
	235	{
	236	if (c == illegal_char[i])
	237	return '_';
	238	i++;
	239	}
	240	return c;
	241	}
	242
	243	/////////////////////////////////////////////////////////////////////////////////
	244	// This function test if the string argument is a legal SFN (Short File Name)
	245	// and copies this name (removing the .) in the sfn_string argument.
	246	// Criteria for a Short File Name are:
	247	// - separator is '.' (extension is not mandatory)
	248	// - 1 <= name length <= 8
	249	// - 0 <= extension length <= 3
	250	// - no illegal character (see illega_short() function)
	251	// Return 1 if it string is a legal SFN
	252	// Return 0 if not legal SFN
	253	/////////////////////////////////////////////////////////////////////////////////
	254	static int is_short( char* string,
	255	char* sfn_string)
	256	{
	257	int s_size = 0;
	258	int dot_ext = 0; // dot offset in the filename
	259	int name_len = 0; // length of file name
	260	int ext_len = 0; // length of extension
	261	int i = 0;
	262	int sc_i = 0;
	263	char ch;
	264
	265	#if GIET_DEBUG_FAT
[295]	266	_printf("\n[FAT DEBUG] filename %s", string );
[258]	267	#endif
	268
	269	if(string[0] == '.' && string[1] == '\0')
	270	{
	271	sfn_string[0] = '.';
	272
	273	#if GIET_DEBUG_FAT
[295]	274	_printf(" converted to 8.3 SFN format : %s\n", sfn_string );
[258]	275	#endif
	276
	277	return 1;
	278	}
	279
	280	if(string[0] == '.' && string[1] == '.' && string[2] == '\0')
	281	{
	282	sfn_string[0] = '.';
	283	sfn_string[1] = '.';
	284
	285	#if GIET_DEBUG_FAT
[295]	286	_printf(" converted to 8.3 SFN format : %s\n", sfn_string );
[258]	287	#endif
	288
	289	return 1;
	290	}
	291
	292	sfn_string[11] = '\0';
	293
	294	while (string[s_size] != '\0')
	295	{
	296	if (string[s_size] == '.')
	297	{
	298	dot_ext = s_size;
	299	ext_len = -1;
	300	}
	301	ext_len++;
	302	s_size++;
	303	}
	304
	305	if (dot_ext != 0)
	306	{
	307	name_len = s_size - ext_len - 1;
	308	}
	309	else
	310	{
	311	name_len = s_size;
	312	ext_len = 0;
	313	}
	314
	315	if ( ext_len > 3 \|\| ( name_len > 8))
	316	{
	317	return 0;
	318	}
	319
	320	if (dot_ext != 0)
	321	{
	322	while (i != ext_len)
	323	{
	324	ch = to_upper(string[dot_ext + 1 + i]);
	325	ch = illegal_short(ch);
	326	sfn_string[8+i] = ch;
	327	i++;
	328	}
	329	}
	330	i = 0;
	331	sc_i = 0;
	332	while (i!= name_len)
	333	{
	334	ch = to_upper(string[i]);
	335	ch = illegal_short(ch);
	336	if (ch != '.')
	337	sfn_string[sc_i++] = ch;
	338	i++;
	339	}
	340
	341	#if GIET_DEBUG_FAT
[295]	342	_printf(" converted to 8.3 SFN format : %s\n", sfn_string );
[258]	343	#endif
	344
	345	return 1;
	346	}
	347
[291]	348	///////////////////////////////////////////////////////////////////////
	349	// This function analyses the pathname argument, from the character
	350	// defined by the *nb_read argument.
	351	// It copies the found name (between '/') in the name[] buffer,
	352	// and updates the nb_read argument.
	353	// Return 1 if name found, Return 0 if NUL character found,
	354	///////////////////////////////////////////////////////////////////////
	355	static int get_name_from_path( char* pathname,
	356	char* name,
	357	unsigned int* nb_read )
	358	{
	359	if ( pathname[*nb_read] == 0 ) return 0;
	360
	361	int i = (pathname[nb_read] == '/')? (nb_read) + 1 : *nb_read;
	362	int j = 0;
	363
	364	while(pathname[i] != '/' && pathname[i] != '\0')
	365	{
	366	name[j] = pathname[i];
	367	j++;
	368	i++;
	369	}
	370	name[j] = 0;
	371
	372	if ( pathname[i] == '/' ) *nb_read += j+1;
	373	else *nb_read += j;
	374
	375	return 1;
	376	}
	377
[258]	378	////////////////////////////////////////////////////////////////////////////////
	379	static int get_name_from_short( char* dir_entry, // input: SFN dir_entry
	380	char* entry_name ) // output: name
	381	{
	382	unsigned int i = 0;
	383	unsigned int length = get_length(DIR_NAME);
	384
	385	while ( i < length )
	386	{
	387	entry_name[i] = dir_entry[i];
	388	i++;
	389	}
	390	entry_name[i] = '\0';
	391
	392	return i;
	393	}
[291]	394
[258]	395	///////////////////////////////////////////////////////////////////////////////
[291]	396	static int get_name_from_long( char *dir_entry, // input : LFN dir_entry
	397	char *entry_name ) // output : name
[258]	398	{
	399	unsigned int entry_name_offset = 0;
	400	unsigned int dir_entry_offset = get_length(LDIR_ORD);
	401	unsigned int l_name_1 = get_length(LDIR_NAME_1);
	402	unsigned int l_name_2 = get_length(LDIR_NAME_2);
	403	unsigned int l_name_3 = get_length(LDIR_NAME_3);
	404	unsigned int l_attr = get_length(LDIR_ATTR);
	405	unsigned int l_type = get_length(LDIR_TYPE);
	406	unsigned int l_chksum = get_length(LDIR_CHKSUM);
	407	unsigned int l_rsvd = get_length(LDIR_RSVD);
	408
	409	unsigned int j = 0;
	410	unsigned int eof = 0;
	411
	412	while ( (dir_entry_offset != DIR_ENTRY_SIZE) && (!eof) )
	413	{
	414	while (j != l_name_1 && !eof )
	415	{
	416	if ( (dir_entry[dir_entry_offset] == 0x00) \|\|
	417	(dir_entry[dir_entry_offset] == 0xFF) )
	418	{
	419	eof = 1;
	420	continue;
	421	}
	422	entry_name[entry_name_offset] = dir_entry[dir_entry_offset];
	423	dir_entry_offset += 2;
	424	j += 2;
	425	entry_name_offset++;
	426	}
	427
	428	dir_entry_offset += (l_attr + l_type + l_chksum);
	429	j = 0;
	430
	431	while (j != l_name_2 && !eof )
	432	{
	433	if ( (dir_entry[dir_entry_offset] == 0x00) \|\|
	434	(dir_entry[dir_entry_offset] == 0xFF) )
	435	{
	436	eof = 1;
	437	continue;
	438	}
	439	entry_name[entry_name_offset] = dir_entry[dir_entry_offset];
	440	dir_entry_offset += 2;
	441	j += 2;
	442	entry_name_offset++;
	443	}
	444
	445	dir_entry_offset += l_rsvd;
	446	j = 0;
	447
	448	while (j != l_name_3 && !eof )
	449	{
	450	if ( (dir_entry[dir_entry_offset] == 0x00) \|\|
	451	(dir_entry[dir_entry_offset] == 0xFF) )
	452	{
	453	eof = 1;
	454	continue;
	455	}
	456	entry_name[entry_name_offset] = dir_entry[dir_entry_offset];
	457	dir_entry_offset += 2;
	458	j += 2;
	459	entry_name_offset++;
	460	}
	461	}
	462	entry_name[entry_name_offset] = '\0';
	463
	464	return entry_name_offset;
	465	} // end get_name_from_long()
	466
[291]	467	//////////////////////////////////////////////////////////////////////////////////////
	468	// This function update a DIR_ENTRY, write a new value into a specific field
	469	// (ex : DIR_FILE_SIZE, when we want update the file size after a fat_write)
	470	// Return 0 in case of success, > 0 if failure.
	471	//////////////////////////////////////////////////////////////////////////////////////
	472	// TODO : make this function less complex
	473	//////////////////////////////////////////////////////////////////////////////////////
	474	static inline unsigned int update_entry( unsigned int fd_id,
	475	unsigned int field,
	476	unsigned int size,
	477	unsigned int value )
	478	{
	479	char dir_entry[32]; // buffer to store a full directory_entry
	480	char name_entry[14]; // buffer to store a 13 characters (partial) name
	481	char file_name[256]; // buffer to store the name (not pathname) of the file
	482	char sfn[12] = {[0 ... 10] = ' ', '\0'}; // buffer for a Short File Name
	483
	484	unsigned int lba = fat.fd[fd_id].lba_dir_entry; // Lba of file dir_entry
	485	unsigned int is_sfn;
	486	unsigned int attr = 0; // directory entry attribute
	487	unsigned int ord = 0; // directory entry sequence
	488	unsigned int found = 0; // name found
	489	unsigned int offset = 0;
	490	unsigned int i = 0;
	491	unsigned int nb_read = 0;
	492
	493	for ( i = 0 ; i < 32 ; i++ ) dir_entry[i] = 0;
	494	for ( i = 0 ; i < 14 ; i++ ) name_entry[i] = 0;
	495
	496	// Get the name of the file.
	497	while ( get_name_from_path( fat.fd[fd_id].name, file_name, &nb_read ) )
	498	{
	499	}
	500
	501	// Check if file_name is short
	502	is_sfn = is_short( file_name, sfn );
	503
[295]	504	if ( _ioc_read( 0, // channel
	505	IOC_KERNEL_MODE, // mode for IOC driver
[291]	506	lba, // sector index
	507	fat.fat_cache, // buffer address
	508	1 ) ) // one sector
	509	{
[295]	510	_printf("[FAT ERROR] in update_entry() cannot read sector %x\n", lba );
[291]	511	return 1;
	512	}
	513	fat.cache_lba = lba;
	514
	515	// - the offset increment is an integer number of directory entry (32 bytes)
	516	// - the exit condition is success (name found) or failure (end of directory)
	517	while ( !found )
	518	{
	519	attr = read_entry( DIR_ATTR, fat.fat_cache + offset, 0 );
	520	ord = read_entry( LDIR_ORD, fat.fat_cache + offset, 0 );
	521
	522	if ( is_sfn == 1 ) // searched name is short
	523	{
	524	if ( (ord != FREE_ENTRY ) &&
	525	(ord != NO_MORE_ENTRY) &&
	526	(attr == ATTR_LONG_NAME_MASK) ) // LFN entry : skipped
	527	{
	528	offset = offset + ((ord & 0xF) * DIR_ENTRY_SIZE);
	529	continue;
	530	}
	531	else if ( (attr != ATTR_LONG_NAME_MASK) &&
	532	(ord != FREE_ENTRY) &&
	533	(ord != NO_MORE_ENTRY ) ) // SFN entry : checked
	534	{
	535	_memcpy( dir_entry, fat.fat_cache + offset, DIR_ENTRY_SIZE );
	536	}
	537	else if (ord == NO_MORE_ENTRY ) // end of directory : return
	538	{
[295]	539	_printf("[FAT ERROR] in update_entry() : reaches end of directory\n");
[291]	540	return 1;
	541	}
	542	else // free entry : skipped
	543	{
	544	offset = offset + DIR_ENTRY_SIZE;
	545	continue;
	546	}
	547	}
	548	else // searched name is long
	549	{
	550	if ( (attr == ATTR_LONG_NAME_MASK) &&
	551	(ord != FREE_ENTRY) &&
	552	(ord != NO_MORE_ENTRY) ) // LFN entry : checked
	553	{
	554	_memcpy( dir_entry, fat.fat_cache + offset, DIR_ENTRY_SIZE );
	555	}
	556	else if ( (attr != ATTR_LONG_NAME_MASK) &&
	557	(ord != FREE_ENTRY) &&
	558	(ord != NO_MORE_ENTRY)) // SFN entry : skipped
	559	{
	560	offset = offset + DIR_ENTRY_SIZE;
	561	continue;
	562	}
	563	else if (ord == NO_MORE_ENTRY ) // end of directory : return
	564	{
[295]	565	_printf("[FAT ERROR] in update_entry() reaches end of directory\n");
[291]	566	return 1;
	567	}
	568	else // free entry : skipped
	569	{
	570	offset = offset + DIR_ENTRY_SIZE;
	571	continue;
	572	}
	573	}
	574
	575	// testing the name extracted from dir entry
	576
	577	if ( is_sfn == 1 ) // searched name is short
	578	{
	579	get_name_from_short( dir_entry, name_entry );
	580
	581	if ( _strncmp( (char)sfn, (char)name_entry, 13 ) == 0 )
	582	{
	583	write_entry(offset + field, size, fat.fat_cache, value);
	584	found = 1;
	585	}
	586	else // no matching : skip
	587	{
	588	offset = offset + DIR_ENTRY_SIZE;
	589	}
	590	}
	591	else // searched name is long
	592	{
	593	get_name_from_long( dir_entry, name_entry );
	594
	595	unsigned shift = ((ord & 0xf) - 1) * 13;
	596	if ( _strncmp( (char)(file_name + shift), (char)name_entry, 13 ) == 0 )
	597	{
	598	if ( (ord & 0xf) == 1 )
	599	{
	600	offset = offset + DIR_ENTRY_SIZE;
	601	write_entry(offset + field, size, fat.fat_cache, value);
	602	found = 1;
	603	}
	604	offset = offset + DIR_ENTRY_SIZE;
	605	continue;
	606	}
	607	else // no matching : skip
	608	{
	609	offset = offset + ((ord & 0xf) * DIR_ENTRY_SIZE) + DIR_ENTRY_SIZE;
	610	}
	611	}
	612	}
	613
[295]	614	return _ioc_write( 0, // channel
	615	IOC_KERNEL_MODE, // mode
	616	lba, // sector index
	617	fat.fat_cache, // source buffer
	618	1 ); // one sector
[291]	619	}
	620	//////////////////////////////////////////////////////////////////////////////////
[295]	621	// This function update FS_INFO:
	622	// last cluster allocated and number of free cluster.
[291]	623	// Return 0 in case of success, > 0 if failure.
	624	//////////////////////////////////////////////////////////////////////////////////
	625	static inline unsigned int update_fs_info( )
	626	{
	627	unsigned int lba = fat.fs_info_lba;
	628
	629	#if GIET_DEBUG_FAT
[295]	630	_printf("\n[FAT DEBUG] Enter update_fs_info()\n");
[291]	631	#endif
	632
	633	if ( lba == fat.cache_lba ) // hit cache
	634	{
	635	write_entry( FS_FREE_CLUSTER , fat.fat_cache, fat.number_free_cluster );
	636	write_entry( FS_FREE_CLUSTER_HINT, fat.fat_cache, fat.last_cluster_allocated );
	637	}
	638	else // miss cache
	639	{
[295]	640	if ( _ioc_read( 0, // channel
	641	IOC_KERNEL_MODE, // mode for IOC driver
[291]	642	lba, // sector index
[295]	643	fat.fat_cache, // source buffer
[291]	644	1 ) ) // one sector
	645	{
[295]	646	_printf("[FAT_ERROR] in update_fat() cannot read block %x\n", lba );
[291]	647	return 1;
	648	}
	649	fat.cache_lba = lba;
	650	write_entry( FS_FREE_CLUSTER , fat.fat_cache, fat.number_free_cluster );
	651	write_entry( FS_FREE_CLUSTER_HINT, fat.fat_cache, fat.last_cluster_allocated );
	652	}
[295]	653	return _ioc_write( 0, // channel
	654	IOC_KERNEL_MODE, // mode
	655	lba, // sector index
	656	fat.fat_cache, // source buffer
	657	1 ); // one sector
[291]	658	}
	659
	660	//////////////////////////////////////////////////////////////////////////////////
	661	// This function update FAT, write a new value into cluster index.
	662	// Used by the function _fat_allocate to update the chaining of clusters.
	663	// Return 0 in case of success, > 0 if failure.
	664	//////////////////////////////////////////////////////////////////////////////////
	665	static inline unsigned int update_fat( unsigned int cluster,
	666	unsigned int value )
	667	{
[300]	668	unsigned int lba = fat.fat_lba + (cluster / 128);
[291]	669
	670	#if GIET_DEBUG_FAT
[295]	671	_printf("\n[FAT DEBUG] Enter update_fat() : cluster = %x / value = %x\n",
	672	cluster, value );
[291]	673	#endif
	674
	675	if ( lba == fat.cache_lba ) // hit cache
	676	{
	677	write_entry( ((cluster % 128) << 2), 4, fat.fat_cache, value );
	678	}
	679	else // miss cache
	680	{
[295]	681	if ( _ioc_read( 0, // channel
	682	IOC_KERNEL_MODE, // mode for IOC driver
[291]	683	lba, // sector index
[295]	684	fat.fat_cache, // source buffer
[291]	685	1 ) ) // one sector
	686	{
[295]	687	_printf("[FAT_ERROR] in update_fat() cannot read block %x\n");
[291]	688	return 1;
	689	}
	690	fat.cache_lba = lba;
	691	write_entry( ((cluster % 128) << 2), 4, fat.fat_cache, value );
	692	}
[295]	693	return _ioc_write( 0, // channel
	694	IOC_KERNEL_MODE, // mode
	695	lba, // sector indexs
	696	fat.fat_cache, // source buffer
	697	1 ); // one sector
[291]	698	}
	699
	700	//////////////////////////////////////////////////////////////////////////////////
	701	// This function allocate a count number of cluster to a file by calling the
	702	// update_fat function that takes care to update the chaining of clusters.
	703	// return 0 if success, -1 if failure
	704	//////////////////////////////////////////////////////////////////////////////////
	705	static inline int _fat_allocate( unsigned int fd_id,
	706	unsigned int count )
	707	{
	708	unsigned int next_cluster = fat.fd[fd_id].first_cluster; // Get the first cluster of file
	709	unsigned int cluster_to_allocate = count; // Number of cluster to allocate
	710
	711	unsigned int last_cluster_file; // Last cluster of the file (EOC)
	712
	713	unsigned int free_cluster = fat.last_cluster_allocated + 1; // First free cluster
	714
	715	// Check if free_cluster is really free (must be true)
	716	if ( get_next_cluster_id( IOC_KERNEL_MODE, free_cluster ) != FREE_CLUSTER)
	717	{
[295]	718	_printf("\n[FAT ERROR] in _fat_allocate() : first free_cluster not free\n");
[291]	719	return -1;
	720	}
	721	// Check if FAT contains enough cluster free for this allocation
	722	if ( count > fat.number_free_cluster )
	723	{
[295]	724	_printf("\n[FAT ERROR] in _fat_allocate() : Not enough free cluster(s)\n");
[291]	725	return -1;
	726	}
	727
	728	#if GIET_DEBUG_FAT
[295]	729	_printf("\n[FAT DEBUG] Enter in _fat_allocate() for file %d\n", fd_id );
[291]	730	#endif
	731
	732	// Get the last cluster allocated for the file (seek END_OF_CHAIN_CLUSTER).
	733	do{
	734	last_cluster_file = next_cluster;
	735	next_cluster = get_next_cluster_id( IOC_KERNEL_MODE, next_cluster );
	736	}while ( next_cluster < END_OF_CHAIN_CLUSTER );
	737
	738	// Loop on the number of cluster needed to be allocated
	739	while ( cluster_to_allocate > 0 )
	740	{
	741
	742	#if GIET_DEBUG_FAT
[295]	743	_printf("\n[FAT DEBUG] cluster to update = %x / free cluster = %x / clusters required = %d\n",
	744	last_cluster_file, free_cluster, cluster_to_allocate );
[291]	745	#endif
	746
	747	// update, in the FAT, the value of last cluster allocated by the index
	748	// of free cluster.
	749	if ( update_fat( last_cluster_file, free_cluster ) )
	750	{
[295]	751	_printf("\n[FAT ERROR] in _fat_allocate() : update fat failed\n");
[291]	752	return -1;
	753	}
	754
	755	cluster_to_allocate = cluster_to_allocate - 1;
	756	// Last cluster allocated is then free_cluster
	757	last_cluster_file = free_cluster;
	758
	759	// Last cluster to allocate done, then we must close the chain of clusters
	760	if ( cluster_to_allocate == 0 )
	761	{
	762	// update, in the FAT, the value of the last cluster allocated by
	763	// END_OF_CHAIN_CLUSTER
	764	if ( update_fat( last_cluster_file, END_OF_CHAIN_CLUSTER ) )
	765	{
[295]	766	_printf("\n[FAT ERROR] in _fat_allocate() : update fat failed\n");
[291]	767	return -1;
	768	}
	769	}
	770
	771	free_cluster = free_cluster + 1;
	772
	773	// Check if free_cluster is really free (must be true)
	774	if ( get_next_cluster_id( IOC_KERNEL_MODE, free_cluster ) != FREE_CLUSTER)
	775	{
[295]	776	_printf("\n[FAT ERROR] in _fat_allocate() : free_cluster not free\n");
[291]	777	return -1;
	778	}
	779	}
	780
	781	// Update field number_free_cluster and last_cluster_allocated
	782	// of structure fat for next fat_allocate
	783	fat.last_cluster_allocated = last_cluster_file;
	784	fat.number_free_cluster = fat.number_free_cluster - count;
	785
	786	if ( update_fs_info() )
	787	{
[295]	788	_printf("\n[FAT ERROR] in _fat_allocate() : update fs_info failed\n");
[291]	789	return -1;
	790	}
	791
	792	return 0;
	793	}
	794
	795	///////////////////////////////////////////////////////////////////////////////
	796	// This function returns the cluster index from a (32 bytes) directory entry
	797	///////////////////////////////////////////////////////////////////////////////
	798	static inline unsigned int read_cluster( char* buf )
	799	{
	800	unsigned int cluster = read_entry( DIR_FST_CLUS_HI, buf, 1 ) << 16;
	801	cluster = cluster \| read_entry( DIR_FST_CLUS_LO, buf, 1 );
	802	return cluster;
	803	}
	804
	805
[258]	806	////////////////////////////////////////////////////////////////////////////////////////
	807	// This function read the blocks defined by the cluster index argument, in a data
	808	// region containing a directory to search the name of a file/firectory,
	809	// and returns the cluster index of the file/directory when the name has been found.
	810	// Return cluster index if name found / Return -1 if not found,
	811	////////////////////////////////////////////////////////////////////////////////////////
[291]	812	static int scan_directory( unsigned int mode, // mode for IOC driver
	813	unsigned int cluster, // cluster containing dir_entry
	814	char* file_name, // searched file/directory name
	815	unsigned int* file_size, // file size
	816	unsigned int* lba_dir_entry ) // lba of dir_entry
[258]	817	{
	818
	819	#if GIET_DEBUG_FAT
[300]	820	_printf("\n[FAT DEBUG] enter _scan_directory() searching dir/file %s", file_name );
[258]	821	#endif
	822
	823	char dir_entry[32]; // buffer to store a full directory_entry
	824	char name_entry[14]; // buffer to store a 13 characters (partial) name
	825
	826	char sfn[12] = {[0 ... 10] = ' ', '\0'}; // buffer for a Short File Name
	827	unsigned int is_sfn = is_short(file_name, sfn); // if file_name is short, sfn = 1
	828	unsigned int offset = 0; // byte offset in block
	829	unsigned int block_id = fat.sectors_per_cluster; // sector index initialisation
	830	unsigned int lba = cluster_to_lba(cluster);
	831	unsigned int attr = 0; // directory entry attribute
	832	unsigned int ord = 0; // directory entry sequence
	833	unsigned int found = 0; // name found
	834	unsigned int i;
	835
	836	for( i = 0 ; i < 32 ; i++ ) dir_entry[i] = 0;
	837	for( i = 0 ; i < 14 ; i++ ) name_entry[i] = 0;
	838
	839	// load first cluster sector from DATA region into FAT cache
	840	// other sectors will be loaded inside loop as required
[295]	841	if( _ioc_read( 0, // channel
	842	mode, // mode for IOC driver
[258]	843	lba, // sector index
	844	fat.fat_cache, // buffer address
	845	1 ) ) // one sector
	846	{
[295]	847	_printf("[FAT ERROR] in scan directory() cannot read sector %x\n", lba );
[258]	848	return -1;
	849	}
	850
	851	fat.cache_lba = lba;
	852
[295]	853	#if GIET_DEBUG_FAT
	854	display_fat_cache();
	855	#endif
[258]	856
	857	// in this loop we scan all names in directory identified by cluster:
	858	// - the offset increment is an integer number of directory entry (32 bytes)
	859	// - the exit condition is success (name found) or failure (end of directory)
	860	while( 1 )
	861	{
	862	// load a new sector if required
	863	if (offset >= 512)
	864	{
	865	if ( block_id ) // not a new cluster
	866	{
	867	lba += 1;
	868	block_id --;
	869	}
	870	else // get next cluster
	871	{
	872	cluster = get_next_cluster_id( mode, cluster );
	873
	874	if ( cluster >= END_OF_CHAIN_CLUSTER ) return END_OF_CHAIN_CLUSTER;
	875
	876	lba = cluster_to_lba(cluster);
	877	block_id = fat.sectors_per_cluster;
	878	}
[295]	879	if( _ioc_read( 0, // channel
	880	mode, // mode for IOC driver
[291]	881	lba, // sector index
[258]	882	fat.fat_cache, // buffer address
[291]	883	1 ) ) // one sector
[258]	884	{
[295]	885	_printf("[FAT ERROR] in scan directory() cannot read sector %x\n", lba );
[258]	886	return -1;
	887	}
	888	fat.cache_lba = lba;
	889	block_id--;
	890	offset = offset % 512;
	891	}
	892
	893	// analyse a directory entry (pointed by fat.fat_cache + offset)
	894	if ( !found )
	895	{
	896	attr = read_entry( DIR_ATTR, fat.fat_cache + offset, 0);
	897	ord = read_entry( LDIR_ORD, fat.fat_cache + offset, 0);
	898
	899	if ( is_sfn == 1 ) // searched name is short
	900	{
	901	if ( (ord != FREE_ENTRY ) &&
	902	(ord != NO_MORE_ENTRY) &&
	903	(attr == ATTR_LONG_NAME_MASK) ) // LFN entry : skipped
	904	{
	905	offset = offset + ((ord & 0xF) * DIR_ENTRY_SIZE);
	906	continue;
	907	}
	908	else if ( (attr != ATTR_LONG_NAME_MASK) &&
	909	(ord != FREE_ENTRY) &&
	910	(ord != NO_MORE_ENTRY ) ) // SFN entry : checked
	911	{
	912	_memcpy( dir_entry, fat.fat_cache + offset, DIR_ENTRY_SIZE );
	913	offset = offset + DIR_ENTRY_SIZE;
	914	}
	915	else if (ord == NO_MORE_ENTRY ) // end of directory : return
	916	{
	917	return END_OF_CHAIN_CLUSTER;
	918	}
	919	else // free entry : skipped
	920	{
	921	offset = offset + DIR_ENTRY_SIZE;
	922	continue;
	923	}
	924	}
	925	else // searched name is long
	926	{
	927	if( (attr == ATTR_LONG_NAME_MASK) &&
	928	(ord != FREE_ENTRY) &&
	929	(ord != NO_MORE_ENTRY) ) // LFN entry : checked
	930	{
	931	_memcpy( dir_entry, fat.fat_cache + offset, DIR_ENTRY_SIZE );
	932	offset = offset + DIR_ENTRY_SIZE;
	933	}
	934	else if( (attr != ATTR_LONG_NAME_MASK) &&
	935	(ord != FREE_ENTRY) &&
	936	(ord != NO_MORE_ENTRY)) // SFN entry : skipped
	937	{
	938	offset = offset + DIR_ENTRY_SIZE;
	939	continue;
	940	}
	941	else if (ord == NO_MORE_ENTRY ) // end of director : return
	942	{
	943	return END_OF_CHAIN_CLUSTER;
	944	}
	945	else // free entry : skipped
	946	{
	947	offset = offset + DIR_ENTRY_SIZE;
	948	continue;
	949	}
	950	}
	951
	952	// testing the name extracted from dir entry
	953	if ( is_sfn == 1 ) // searched name is short
	954	{
	955	get_name_from_short( dir_entry, name_entry );
	956
	957	if ( _strncmp( (char)sfn, (char)name_entry, 13 ) == 0 )
	958	{
	959	*file_size = read_entry( DIR_FILE_SIZE , dir_entry, 1 );
[291]	960	*lba_dir_entry = lba;
[258]	961	return read_cluster( dir_entry );
	962	}
	963	}
	964	else // searched name is long
	965	{
	966	get_name_from_long( dir_entry, name_entry );
	967
	968	unsigned shift = ((ord & 0xf) - 1) * 13;
	969	if ( _strncmp( (char)(file_name + shift), (char)name_entry, 13 ) == 0 )
	970	{
	971	if( (ord & 0xf) == 1 ) found = 1;
	972	continue;
	973	}
	974	else // no matching : skip
	975	{
	976	offset = offset + ((ord & 0xf) * DIR_ENTRY_SIZE);
	977	}
	978	}
	979	}
	980	else // file found
	981	{
	982	_memcpy( dir_entry, fat.fat_cache + offset, DIR_ENTRY_SIZE );
	983	offset = offset + DIR_ENTRY_SIZE;
	984	*file_size = read_entry( DIR_FILE_SIZE, dir_entry, 1 );
[291]	985	*lba_dir_entry = lba;
[258]	986
	987	return read_cluster( dir_entry );
	988	}
	989	}
	990	return -1;
	991	} // end scan_directory()
	992
	993
	994	//////////////////////////////////////////////////////////////////////
	995	// This function create a new entry in a directory identified
	996	// by "dir_cluster". The name is defined by "name".
	997	// The type (dir/file) is defined by "is_file".
	998	// Returns cluster index if success, Returns -1 if error.
	999	//////////////////////////////////////////////////////////////////////
	1000	static int fat_create( char* name,
	1001	unsigned int is_file,
	1002	unsigned int dir_cluster )
	1003	{
[295]	1004	_printf("\n[FAT ERROR] _fat_create() not implemented\n");
[258]	1005	return 0;
	1006	} //end _fat_create()
	1007
	1008
	1009
	1010	////////////// Extern functions //////////////////////////////////////////
	1011
	1012	//////////////////////////////////////////////////////////////////////////
	1013	// This function initializes the FAT structure, including the
	1014	// files descriptors array, from informations found in the boot record.
	1015	//////////////////////////////////////////////////////////////////////////
	1016	// Return 0 if success, Return -1 if failure
	1017	//////////////////////////////////////////////////////////////////////////
	1018	int _fat_init( unsigned int mode ) // mode for IOC driver
	1019	{
	1020	unsigned int n;
	1021
	1022	#if GIET_DEBUG_FAT
[295]	1023	unsigned int procid = _get_procid();
	1024	unsigned int cid = procid / NB_PROCS_MAX;
	1025	unsigned int lpid = procid % NB_PROCS_MAX;
	1026	unsigned int x = cid >> Y_WIDTH;
	1027	unsigned int y = cid & ((1<<Y_WIDTH) - 1);
	1028
	1029	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] enters _fat_init()\n",
	1030	x, y, lpid );
[258]	1031	#endif
	1032
[300]	1033	// load Boot Record (VBR) into fat cache
[295]	1034	if ( _ioc_read( 0, // channel
	1035	mode, // mode for IOC driver
[300]	1036	0, // sector index
[258]	1037	fat.fat_cache, // buffer address
[291]	1038	1 ) ) // one sector
[258]	1039	{
[300]	1040	_printf("\n[FAT ERROR] in _fat_init() cannot load VBR\n");
[258]	1041	return -1;
	1042	}
[300]	1043	fat.cache_lba = 0;
[258]	1044
	1045	#if GIET_DEBUG_FAT
[300]	1046	_printf("\n[FAT DEBUG] Boot Sector Loaded\n");
[314]	1047	display_fat_cache();
[258]	1048	#endif
	1049
	1050	// checking various FAT32 assuptions from boot sector
	1051	if( read_entry( BPB_BYTSPERSEC, fat.fat_cache, 1 ) != 512 )
	1052	{
[295]	1053	_printf("\n[FAT ERROR] The sector size must be 512 bytes\n");
[258]	1054	return -1;
	1055	}
	1056	if( read_entry( BPB_NUMFATS, fat.fat_cache, 1 ) != 1 )
	1057	{
[295]	1058	_printf("\n[FAT ERROR] The number of FAT copies in FAT region must be 1\n");
[258]	1059	return -1;
	1060	}
	1061	if( (read_entry( BPB_FAT32_FATSZ32, fat.fat_cache, 1 ) & 0xF) != 0 )
	1062	{
[295]	1063	_printf("\n[FAT ERROR] The FAT region in FAT32 must be multiple of 32 sectors\n");
[258]	1064	return -1;
	1065	}
	1066	if( read_entry( BPB_FAT32_ROOTCLUS, fat.fat_cache, 1 ) != 2 )
	1067	{
[295]	1068	_printf("\n[FAT ERROR] The first cluster index must be 2\n");
[258]	1069	return -1;
	1070	}
[300]	1071	// FS Info always in sector 1
	1072	fat.fs_info_lba = read_entry( BPB_FAT32_FSINFO, fat.fat_cache, 1 );
[258]	1073
[300]	1074	// initialise fat descriptor from VBR
[258]	1075	fat.sectors_per_cluster = read_entry( BPB_SECPERCLUS, fat.fat_cache, 1 );
	1076	fat.sector_size = read_entry( BPB_BYTSPERSEC, fat.fat_cache, 1 );
	1077	fat.cluster_size = fat.sectors_per_cluster * 512;
	1078	fat.fat_sectors = read_entry( BPB_FAT32_FATSZ32, fat.fat_cache, 1 );
[300]	1079	fat.fat_lba = read_entry( BPB_RSVDSECCNT, fat.fat_cache, 1 );
	1080	fat.data_lba = fat.fat_lba + fat.fat_sectors;
[258]	1081	fat.initialised = FAT_INITIALISED;
	1082
	1083	// initialise file descriptor array
	1084	for( n = 0 ; n < GIET_OPEN_FILES_MAX ; n++ ) fat.fd[n].used = 0;
	1085
[291]	1086	#if GIET_DEBUG_FAT
[295]	1087	_printf("\n[FAT DEBUG] FS_INFO Sector = %x\n", fat.fs_info_lba );
[291]	1088	#endif
	1089
	1090	// load FS_INFO into fat cache
[295]	1091	if ( _ioc_read( 0, // channel
	1092	mode, // mode for IOC driver
[291]	1093	fat.fs_info_lba, // sector index
	1094	fat.fat_cache, // buffer address
	1095	1 ) ) // one sector
	1096	{
[295]	1097	_printf("\n[FAT ERROR] in _fat_init() cannot load FS_INFO Sector\n");
[291]	1098	return -1;
	1099	}
	1100	fat.cache_lba = fat.fs_info_lba;
	1101
	1102	fat.number_free_cluster = read_entry( FS_FREE_CLUSTER , fat.fat_cache, 1);
	1103	fat.last_cluster_allocated = read_entry( FS_FREE_CLUSTER_HINT, fat.fat_cache, 1);
	1104
	1105	#if GIET_DEBUG_FAT
[295]	1106	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] exit _fat_init() / "
	1107	"free clusters = %x / last allocated cluster = %x\n",
	1108	fat.number_free_cluster, fat.last_cluster_allocated );
[291]	1109	#endif
	1110
[258]	1111	return 0;
	1112	} // end _fat_init()
	1113
	1114	/////////////////
	1115	void _fat_print()
	1116	{
[295]	1117	_printf("\n########################## FAT32 ###########################");
[337]	1118	_printf("\nFAT initialised %x", fat.initialised );
[295]	1119	_printf("\nSector Size (bytes) %x", fat.sector_size );
	1120	_printf("\nSectors per cluster %x", fat.sectors_per_cluster );
[300]	1121	_printf("\nFAT region first lba %x", fat.fat_lba );
[295]	1122	_printf("\nData region first lba %x", fat.data_lba );
	1123	_printf("\nNumber of sectors for one FAT %x", fat.fat_sectors );
	1124	_printf("\n############################################################\n");
[258]	1125	}
	1126
	1127	///////////////////////////////////////////////////////////////////////////////
	1128	// This function checks that the kernel FAT structure has been initialised,
[263]	1129	// and makes the FAT initialisation if it is the first user open request.
[258]	1130	// This function searches a file identified by the "pathname" argument.
	1131	// It starts from root (cluster 2) to scan successively each subdirectory.
	1132	// When the file is not found, but the path is found, and "creat" is set,
	1133	// a new file is created and introduced in the directory.
	1134	// Finally, it sets a new open file in the file descriptors array.
[295]	1135	// The same file can be open several times by differents taks.
[258]	1136	///////////////////////////////////////////////////////////////////////////////
	1137	// Returns file descriptor index if success, returns -1 if error.
	1138	///////////////////////////////////////////////////////////////////////////////
	1139	int _fat_open( unsigned mode,
	1140	char* pathname,
	1141	unsigned int creat )
	1142	{
	1143	char name[256]; // buffer for one name in pathname
	1144	unsigned int nb_read; // number of characters written in name[]
	1145	unsigned int cluster; // current cluster index when scanning FAT
	1146	unsigned int dir_cluster; // previous cluster index when scanning FAT
	1147	unsigned int fd_id; // index when scanning file descriptors array
	1148	unsigned int file_size; // number of bytes
	1149	unsigned int last_name; // directory containing file name is reached
[291]	1150	unsigned int lba; // lba of dir_entry for this file
[258]	1151
	1152	#if GIET_DEBUG_FAT
[295]	1153	unsigned int procid = _get_procid();
	1154	unsigned int cid = procid / NB_PROCS_MAX;
	1155	unsigned int lpid = procid % NB_PROCS_MAX;
	1156	unsigned int x = cid >> Y_WIDTH;
	1157	unsigned int y = cid & ((1<<Y_WIDTH) - 1);
	1158
	1159	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] enters _fat_open() for file %s\n",
	1160	x, y, lpid, pathname );
[258]	1161	#endif
	1162
[295]	1163	// checking arguments
	1164	if ( creat )
	1165	{
	1166	_printf("[FAT ERROR] in _fat_open() : create not supported yet\n");
	1167	return -1;
	1168	}
	1169
	1170	// takes the FAT lock for exclusive access
	1171	_get_lock( &fat.lock );
	1172
	1173	#if GIET_DEBUG_FAT
	1174	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] takes the FAT lock\n",
	1175	x, y, lpid );
	1176	#endif
	1177
	1178	// FAT initialisation if required
[258]	1179	if( fat.initialised != FAT_INITIALISED )
	1180	{
[289]	1181	if ( _fat_init( mode ) )
	1182	{
[295]	1183	_printf("[FAT ERROR] in _fat_open() : Cannot initialize FAT descriptor\n");
	1184
	1185	// release FAT lock
	1186	_release_lock( &fat.lock );
	1187
	1188	return -1;
[289]	1189	}
	1190
	1191	#if GIET_DEBUG_FAT
[295]	1192	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] initialises FAT descriptor\n",
	1193	x, y, lpid );
[289]	1194	_fat_print();
	1195	#endif
[295]	1196
[258]	1197	}
	1198
[263]	1199	// Scan the directories, starting from the root directory (cluster 2)
[258]	1200	// - The get_name_from_path() function extracts (successively)
	1201	// each directory name from the pathname, and store it in name[] buffer
	1202	// - The scan_directory() function scan one (or several) cluster(s) containing
	1203	// a directory looking for name[], and return the cluster index
	1204	// corresponding to the directory/file found.
	1205	nb_read = 0;
	1206	cluster = 2;
	1207	last_name = 0;
	1208	while ( get_name_from_path( pathname, name, &nb_read) )
	1209	{
	1210
	1211	#if GIET_DEBUG_FAT
[295]	1212	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] search dir/file : %s\n",
	1213	x, y, lpid, name );
[258]	1214	#endif
[291]	1215
[258]	1216	// test if we reach the last name (file name)
	1217	if( pathname[nb_read] == 0 )
	1218	{
	1219	last_name = 1;
	1220	dir_cluster = cluster;
	1221	}
	1222
	1223	// scan current directory
[291]	1224	cluster = scan_directory( mode, cluster, name, &file_size, &lba );
[258]	1225
	1226	if( cluster == END_OF_CHAIN_CLUSTER && last_name && creat )
	1227	{
	1228	cluster = fat_create( name, 1, dir_cluster );
	1229	}
	1230	else if ( cluster == END_OF_CHAIN_CLUSTER )
	1231	{
[295]	1232	_printf("\n[FAT ERROR] in _fat_open() cannot found %s\n", name );
	1233
	1234	// release FAT lock
	1235	_release_lock( &fat.lock );
	1236
[258]	1237	return -1;
	1238	}
	1239	}
	1240
	1241	// check the next value for cluster index found
	1242	unsigned next = get_next_cluster_id( mode, cluster );
	1243
	1244	if ( (next != BAD_CLUSTER) && (next != FREE_CLUSTER) )
	1245	{
	1246	// Search an empty slot scanning open file descriptors array
	1247	fd_id = 0;
	1248	while ( fat.fd[fd_id].used != 0 && fd_id < GIET_OPEN_FILES_MAX )
	1249	{
	1250	fd_id++;
	1251	}
	1252
	1253	// set file descriptor if found empty slot
	1254	if ( fd_id < GIET_OPEN_FILES_MAX )
	1255	{
	1256	fat.fd[fd_id].used = 1;
	1257	fat.fd[fd_id].first_cluster = cluster;
	1258	fat.fd[fd_id].file_size = file_size;
[291]	1259	fat.fd[fd_id].lba_dir_entry = lba;
[258]	1260	_strcpy( fat.fd[fd_id].name, pathname );
	1261
	1262	#if GIET_DEBUG_FAT
[295]	1263	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] open file %s with fd = %d\n",
	1264	x, y, lpid, pathname, fd_id );
[258]	1265	#endif
	1266
[295]	1267	// release FAT lock
	1268	_release_lock( &fat.lock );
	1269
[258]	1270	return fd_id;
	1271	}
	1272	else
	1273	{
[295]	1274	_printf("\n[FAT ERROR] in _fat_open() for file %s : fd array full\n",
	1275	pathname );
	1276
	1277	// release FAT lock
	1278	_release_lock( &fat.lock );
	1279
[258]	1280	return -1;
	1281	}
	1282	}
	1283	else
	1284	{
[295]	1285	_printf("\n[FAT ERROR] in _fat_open() for file %s : bad cluster\n",
	1286	pathname );
	1287
	1288	// release FAT lock
	1289	_release_lock( &fat.lock );
	1290
[258]	1291	return -1;
	1292	}
	1293	} // end _fat_open()
	1294
	1295	///////////////////////////////////////////////////////////////////////////////
	1296	// For an open file, identified by the file descriptor index, transfer
	1297	// an integer number of sectors from block device to a memory buffer.
	1298	// If the number of requested sectors exceeds the file size, it is reduced.
	1299	///////////////////////////////////////////////////////////////////////////////
	1300	// Returns number of sectors transfered if success, < 0 if error.
	1301	///////////////////////////////////////////////////////////////////////////////
	1302	int _fat_read( unsigned int mode, // mode for IOC driver
	1303	unsigned int fd_id, // file descriptor
	1304	void* buffer, // target buffer base address
	1305	unsigned int count, // number of sector to read
	1306	unsigned int offset ) // nuber of sectors to skip in file
	1307	{
	1308
	1309	#if GIET_DEBUG_FAT
[295]	1310	unsigned int procid = _get_procid();
	1311	unsigned int cid = procid / NB_PROCS_MAX;
	1312	unsigned int lpid = procid % NB_PROCS_MAX;
	1313	unsigned int x = cid >> Y_WIDTH;
	1314	unsigned int y = cid & ((1<<Y_WIDTH) - 1);
	1315
[337]	1316	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] enters _fat_read() for file %s\n"
[295]	1317	" - buffer vbase = %x\n"
	1318	" - skipped sectors = %x\n"
	1319	" - read sectors = %x\n",
	1320	x, y, lpid, fat.fd[fd_id].name, (unsigned int)buffer, offset, count );
[258]	1321	#endif
	1322
	1323	unsigned int spc = fat.sectors_per_cluster;
	1324
	1325	unsigned int file_size; // number of bytes in file
	1326	unsigned int file_sectors; // number of sectors in file
	1327	unsigned int total_sectors; // actual number of sectors to be transfered
	1328	unsigned int cluster; // cluster index
	1329	unsigned int clusters_to_skip; // number of clusters to skip because offset
	1330	unsigned int sectors_to_skip; // number of sectors to skip in first iteration
	1331
	1332	// compute file size as a number of sectors
	1333	file_size = fat.fd[fd_id].file_size;
	1334	if ( file_size & 0x1FF ) file_sectors = (file_size >> 9) + 1;
	1335	else file_sectors = (file_size >> 9);
	1336
	1337	// arguments checking
	1338	if ( fd_id >= GIET_OPEN_FILES_MAX )
	1339	{
[295]	1340	_printf("\n[FAT ERROR] in _fat_read() : illegal file descriptor index\n");
[258]	1341	return -1;
	1342	}
	1343	if ( fat.fd[fd_id].used != 1 )
	1344	{
[295]	1345	_printf("\n[FAT ERROR] in _fat_read() : file not open\n");
[258]	1346	return -1;
	1347	}
	1348	if ( ((unsigned int)buffer & 0x1FF) != 0 )
	1349	{
[295]	1350	_printf("\n[FAT ERROR] in _fat_read() : memory buffer not sector aligned\n");
[258]	1351	return -1;
	1352	}
	1353	if ( offset >= file_sectors )
	1354	{
[295]	1355	_printf("\n[FAT ERROR] offset larger than number of sectors\n");
[258]	1356	return -1;
	1357	}
	1358
	1359	// compute total number of sectors to read
	1360	if ( file_sectors < (offset + count) ) total_sectors = file_sectors - offset;
	1361	else total_sectors = count;
	1362
	1363	// compute clusters and sectors to be skipped
	1364	clusters_to_skip = offset / spc;
	1365	sectors_to_skip = offset % spc;
	1366
	1367	// get first cluster index
	1368	cluster = fat.fd[fd_id].first_cluster;
	1369
	1370	#if GIET_DEBUG_FAT
[295]	1371	_printf(" - first cluster = %x\n"
	1372	" - skiped clusters = %x\n",
	1373	cluster, clusters_to_skip );
[258]	1374	#endif
	1375
	1376	// compute index of first cluster to be loaded
	1377	// as we may need to scan the FAT, we use the kernel mode
	1378	while ( clusters_to_skip )
	1379	{
	1380	cluster = get_next_cluster_id( IOC_KERNEL_MODE, cluster );
	1381	clusters_to_skip--;
	1382	}
	1383
	1384	// variables used in the loop on clusters
	1385	int todo_sectors; // number of sectors still to be loaded
	1386	unsigned int lba; // first sector index on device
	1387	unsigned int iter_sectors; // number of sectors to load in iteration
	1388	char* dst; // pointer on target buffer
	1389
	1390	// initialize these variables for the first iteration
	1391	todo_sectors = total_sectors;
	1392	dst = (char*)buffer;
	1393	lba = cluster_to_lba(cluster) + sectors_to_skip;
	1394	if( total_sectors < (spc - sectors_to_skip) ) iter_sectors = total_sectors;
	1395	else iter_sectors = spc - sectors_to_skip;
	1396
	1397	// loop on the clusters
	1398	while ( todo_sectors > 0 )
	1399	{
	1400
	1401	#if GIET_DEBUG_FAT
[295]	1402	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] makes an IOC read :"
	1403	" buf = %x / lba = %x / sectors = %d\n",
	1404	x, y, lpid, (unsigned int)dst, lba, iter_sectors );
[258]	1405	#endif
	1406
[295]	1407	if( _ioc_read( 0, // channel
	1408	mode, // mode for IOC driver
[258]	1409	lba, // first sector index
	1410	dst, // buffer address
	1411	iter_sectors ) ) // number of sectors
	1412	{
[295]	1413	_printf("\n[FAT ERROR] in _fat_read() cannot load block %x\n", lba );
[258]	1414	return -1;
	1415	}
	1416
	1417	// update variables for next iteration
	1418	cluster = get_next_cluster_id( mode, cluster );
	1419	todo_sectors = todo_sectors - iter_sectors;
	1420	dst = dst + (iter_sectors << 9);
	1421	lba = cluster_to_lba(cluster);
	1422	if ( todo_sectors > spc ) iter_sectors = spc;
	1423	else iter_sectors = todo_sectors;
	1424	}
	1425
	1426	// returns number of sectors actually transfered
	1427	return total_sectors;
	1428
	1429	} // end _fat_read()
	1430
	1431	///////////////////////////////////////////////////////////////////////////////
	1432	// For an open file, identified by the file descriptor index, transfer
	1433	// an integer number of sectors from a memory buffer to block device.
	1434	// Allocate new clusters if the offset+count larger than current file size,
	1435	// but the offset should be smaller than the current file size...
	1436	// - fat : pointer on FAT
	1437	// - mode : mode for the IOC driver
	1438	// - fd_id : open file descriptor index
	1439	// - buffer : base address of the memory buffer (must be sector aligned)
	1440	// - offset : number of sectors to skip in file
	1441	// - count : number of sectors to be written.
	1442	///////////////////////////////////////////////////////////////////////////////
	1443	// Returns number of sectors written if success, < 0 if error.
	1444	///////////////////////////////////////////////////////////////////////////////
	1445	int _fat_write( unsigned int mode, // mode for IOC driver
	1446	unsigned int fd_id, // file descriptor
	1447	void* buffer, // target buffer base address
	1448	unsigned int count, // number of sector to write
	1449	unsigned int offset ) // nuber of sectors to skip in file
	1450	{
[259]	1451
	1452	unsigned int spc = fat.sectors_per_cluster;
	1453
	1454	unsigned int file_size; // number of bytes in file
	1455	unsigned int file_sectors; // number of sectors in file
	1456	unsigned int cluster; // cluster index
	1457	unsigned int clusters_to_skip; // number of clusters to skip because offset
	1458	unsigned int sectors_to_skip; // number of sectors to skip in first iteration
	1459	unsigned int allocate; // need allocate or not
[291]	1460	unsigned int current_cluster; // number of cluster allocated to the file
	1461	unsigned int required_cluster; // number of cluster needed for the write
[259]	1462
	1463	// compute file size as a number of sectors
	1464	file_size = fat.fd[fd_id].file_size;
	1465	if ( file_size & 0x1FF ) file_sectors = (file_size >> 9) + 1;
	1466	else file_sectors = (file_size >> 9);
	1467
[291]	1468	// Compute the number of clusters occupied by the file
	1469	current_cluster = file_sectors / spc;
	1470
	1471	// Compute the number of clusters that will occupy the file (after fat_write)
	1472	required_cluster = (count + offset) / spc;
	1473
	1474	// Check if we need to allocate new cluster(s) for the file
	1475	allocate = ( required_cluster > current_cluster );
	1476
[259]	1477	#if GIET_DEBUG_FAT
[295]	1478	unsigned int procid = _get_procid();
	1479	unsigned int cid = procid / NB_PROCS_MAX;
	1480	unsigned int lpid = procid % NB_PROCS_MAX;
	1481	unsigned int x = cid >> Y_WIDTH;
	1482	unsigned int y = cid & ((1<<Y_WIDTH) - 1);
	1483
	1484	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] enters _fat_write() for file %s\n",
	1485	" - buffer vbase = %x\n"
	1486	" - skipped sectors = %x\n"
	1487	" - write sectors = %x\n"
	1488	" - file sectors = %x\n"
	1489	" - need allocate = %d\n",
	1490	x, y, lpid, fat.fd[fd_id].name, (unsigned int)buffer,
	1491	offset, count, file_sectors, allocate );
[259]	1492	#endif
	1493
	1494	// arguments checking
	1495	if ( fd_id >= GIET_OPEN_FILES_MAX )
	1496	{
[295]	1497	_printf("\n[FAT ERROR] in _fat_write() : illegal file descriptor index\n");
[259]	1498	return -1;
	1499	}
	1500	if ( fat.fd[fd_id].used != 1 )
	1501	{
[295]	1502	_printf("\n[FAT ERROR] in _fat_write() : file not open\n");
[259]	1503	return -1;
	1504	}
	1505	if ( ((unsigned int)buffer & 0x1FF) != 0 )
	1506	{
[295]	1507	_printf("\n[FAT ERROR] in _fat_write() : memory buffer not sector aligned\n");
[259]	1508	return -1;
	1509	}
	1510
[291]	1511	if ( allocate )
	1512	{
	1513	if ( _fat_allocate( fd_id, (required_cluster - current_cluster) ) < 0 )
	1514	{
[295]	1515	_printf("\n[FAT ERROR] in _fat_write() : fat_allocate failed\n");
[291]	1516	return -1;
	1517	}
	1518	}
	1519
[259]	1520	// compute clusters and sectors to be skipped
	1521	clusters_to_skip = offset / spc;
	1522	sectors_to_skip = offset % spc;
	1523
	1524	// get first cluster index
	1525	cluster = fat.fd[fd_id].first_cluster;
	1526
	1527	#if GIET_DEBUG_FAT
[295]	1528	_printf(" - first cluster = %x\n"
	1529	" - skiped clusters = %x\n",
	1530	cluster, clusters_to_skip );
[259]	1531	#endif
	1532
	1533	// compute index of first cluster to be loaded
	1534	// as we may need to scan the FAT, we use the kernel mode
	1535	while ( clusters_to_skip )
	1536	{
	1537	cluster = get_next_cluster_id( IOC_KERNEL_MODE, cluster );
	1538	clusters_to_skip--;
	1539	}
	1540
	1541	// variables used in the loop on clusters
	1542	int todo_sectors; // number of sectors still to be loaded
	1543	unsigned int lba; // first sector index on device
	1544	unsigned int iter_sectors; // number of sectors to load in iteration
	1545	char* src; // pointer on target buffer
	1546
	1547	// initialize these variables for the first iteration
	1548	todo_sectors = count;
	1549	src = (char*)buffer;
	1550	lba = cluster_to_lba(cluster) + sectors_to_skip;
	1551	if( count < (spc - sectors_to_skip) ) iter_sectors = count;
	1552	else iter_sectors = spc - sectors_to_skip;
	1553
	1554	// loop on the clusters
	1555	while ( todo_sectors > 0 )
	1556	{
	1557
	1558	#if GIET_DEBUG_FAT
[295]	1559	_printf("\n[FAT DEBUG] Processor[%d,%d,%d] makes an IOC write : "
	1560	"buf = %x / lba = %x / sectors = %x\n",
	1561	x, y, lpid, (unsigned int)src, lba, iter_sectors );
[259]	1562	#endif
	1563
[295]	1564	if( _ioc_write( 0, // channel
	1565	mode, // mode for IOC driver
[259]	1566	lba, // first sector index
[295]	1567	src, // source buffer address
[259]	1568	iter_sectors ) ) // number of sectors
	1569	{
[295]	1570	_printf("\n[FAT ERROR] in _fat_write() cannot write block %x\n", lba );
[259]	1571	return -1;
	1572	}
	1573
	1574	// update variables for next iteration
	1575	cluster = get_next_cluster_id( mode, cluster );
	1576	todo_sectors = todo_sectors - iter_sectors;
	1577	src = src + (iter_sectors << 9);
	1578	lba = cluster_to_lba(cluster);
	1579	if ( todo_sectors > spc ) iter_sectors = spc;
	1580	else iter_sectors = todo_sectors;
	1581	}
[291]	1582
	1583	// Update structure file descriptor, field file_size with
	1584	// the new file size if the file is bigger than the previous file
	1585	if ( ( offset + count ) > file_sectors )
	1586	{
	1587	fat.fd[fd_id].file_size = (count + offset) << 9;
	1588	}
	1589
	1590	// Update entry of directory with the new value
	1591	// of file size (Field : DIR_FILE_SIZE)
	1592	if ( update_entry(fd_id, DIR_FILE_SIZE, fat.fd[fd_id].file_size) )
	1593	{
[295]	1594	_printf("\n[FAT ERROR] in _fat_write() update entry failed\n");
[291]	1595	return -1;
	1596	}
[259]	1597
	1598	// returns number of sectors actually transfered
	1599	return count;
[258]	1600	}
	1601
	1602	/////////////////////////////////////////////////////////////////////////////////
[260]	1603	// Return stats of a file identified by "fd".
	1604	// (Only the file_size in sectors for this moment)
	1605	/////////////////////////////////////////////////////////////////////////////////
	1606	// Returns file size (on sectors) on success, -1 on failure.
	1607	/////////////////////////////////////////////////////////////////////////////////
	1608	int _fat_fstat( unsigned int fd_id )
	1609	{
	1610	unsigned int file_size = 0;
	1611	unsigned int file_sectors = 0;
	1612
	1613	if( (fd_id < GIET_OPEN_FILES_MAX) )
	1614	{
	1615	file_size = fat.fd[fd_id].file_size;
	1616
	1617	if ( file_size & 0x1FF ) file_sectors = (file_size >> 9) + 1;
	1618	else file_sectors = (file_size >> 9);
	1619
	1620	return file_sectors;
	1621	}
	1622	else
	1623	{
[295]	1624	_printf("\n[FAT ERROR] in _fat_fstat() : illegal file descriptor index\n");
[260]	1625	return -1;
	1626	}
	1627	} // end _fat_fstat()
	1628
	1629	/////////////////////////////////////////////////////////////////////////////////
[258]	1630	// Close the file identified by the file_descriptor index.
	1631	/////////////////////////////////////////////////////////////////////////////////
	1632	// Returns 0 on success, -1 on failure.
	1633	/////////////////////////////////////////////////////////////////////////////////
	1634	int _fat_close( unsigned int fd_id )
	1635	{
	1636	if( (fd_id < GIET_OPEN_FILES_MAX) )
	1637	{
	1638	fat.fd[fd_id].used = 0;
	1639	return 0;
	1640	}
	1641	else
	1642	{
[295]	1643	_printf("\n[FAT ERROR] in _fat_close() : illegal file descriptor index\n");
[258]	1644	return -1;
	1645	}
	1646	} // end fat_close()
	1647
	1648	/////////////////////////////////////////////////////////////////////////////////////
	1649	// The following function implement the user_level system call.
	1650	// The flags argument is nor used, as file access modes are not implemented yet.
	1651	/////////////////////////////////////////////////////////////////////////////////////
	1652	// Return the file descriptor index if success / return -1 if failure
	1653	/////////////////////////////////////////////////////////////////////////////////////
	1654	int _fat_user_open( char* pathname, // absolute pathname from root
	1655	unsigned int flags ) // unused: TODO
	1656	{
[295]	1657	return _fat_open( IOC_KERNEL_MODE, // we use KERNEL_MODE, because
[258]	1658	pathname, // we need to write into FAT cache
[295]	1659	0 ); // no creation if not found
[258]	1660	}
	1661
	1662	/////////////////////////////////////////////////////////////////////////////////////
	1663	// The following function implement the user_level system call.
	1664	// This function should be modified to respect the UNIX specification
	1665	/////////////////////////////////////////////////////////////////////////////////////
	1666	// Return number of sectors actually transfered if success / return -1 if failure
	1667	/////////////////////////////////////////////////////////////////////////////////////
	1668	int _fat_user_read( unsigned int fd, // file descriptor index
	1669	void* buffer, // destination buffer
	1670	unsigned int count, // number of sectors to read
	1671	unsigned int offset ) // number of sectors to skip
	1672	{
	1673	return _fat_read( IOC_USER_MODE,
	1674	fd,
	1675	buffer,
	1676	count,
	1677	offset );
	1678	}
	1679
	1680	/////////////////////////////////////////////////////////////////////////////////////
	1681	// The following function implement the user_level system call.
	1682	// This function should be modified to respect the UNIX specification.
	1683	/////////////////////////////////////////////////////////////////////////////////////
	1684	// Return number of sectors actually transfered if success / return -1 if failure
	1685	/////////////////////////////////////////////////////////////////////////////////////
	1686	int _fat_user_write( unsigned int fd, // file descriptor
	1687	void* buffer, // source buffer
	1688	unsigned int count, // number of sectors to write
	1689	unsigned int offset ) // number of sectors to skip on file
	1690	{
	1691	return _fat_write( IOC_USER_MODE,
	1692	fd,
	1693	buffer,
	1694	count,
	1695	offset );
	1696	}
	1697
	1698	/////////////////////////////////////////////////////////////////////////////////////
	1699	int _fat_user_lseek( unsigned int fd_id,
	1700	unsigned int offset,
	1701	unsigned int whence )
	1702	{
[295]	1703	_printf("[GIET ERROR] _fat_user_lseek() not implemented\n");
[258]	1704	_exit();
	1705	return 0;
	1706	}
	1707
	1708
	1709	// Local Variables:
	1710	// tab-width: 4
	1711	// c-basic-offset: 4
	1712	// c-file-offsets:((innamespace . 0)(inline-open . 0))
	1713	// indent-tabs-mode: nil
	1714	// End:
	1715	// vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4
	1716

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