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FAT-12
[File Systems]

Data Structures
struct	attrib
struct	bootsect
struct	date
struct	FAT12
struct	fat_time
struct	FileEntry
struct	logical_FAT12
struct	sector
struct	SectorDir
Defines
#define	FAT_PHYS_SIZE   9
#define	FAT_BOOT_SECTOR   0
#define	FAT_SECTOR_SIZE   512
#define	EOF_FAT12   0xFF8
#define	EOF_FAT16   0xFFF8
#define	EOF_FAT32   0xFFFFFF8
Typedefs
typedef bootsect	bootsect_t
typedef FAT12	FAT12_t
typedef logical_FAT12	logical_FAT12_t
typedef sector	sector_t
typedef FileEntry	FileEntry_t
typedef date	date_t
typedef fat_time	fat_time_t
typedef attrib	attrib_t
typedef SectorDir	SectorDir_t
Functions
bool	Read_FAT ()
bool	load_file (char *stringa, byte *buffer)
int	get_file_size (char *file_name)
char *	pwd ()
void	ls ()
bool	cd (char *new_path)
bool	cat (char *stringa)
bool	rm (char *filename)

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Detailed Description

The FAT-12 file system.

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Define Documentation

#define EOF_FAT12   0xFF8

Definition at line 27 of file fat.h.

#define EOF_FAT16   0xFFF8

Definition at line 28 of file fat.h.

#define EOF_FAT32   0xFFFFFF8

Definition at line 29 of file fat.h.

#define FAT_BOOT_SECTOR   0

Definition at line 24 of file fat.h.

#define FAT_PHYS_SIZE   9

Definition at line 23 of file fat.h.

#define FAT_SECTOR_SIZE   512

Definition at line 25 of file fat.h.

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Typedef Documentation

typedef struct attrib attrib_t

typedef struct bootsect bootsect_t

typedef struct date date_t

typedef struct FAT12 FAT12_t

typedef struct fat_time fat_time_t

typedef struct FileEntry FileEntry_t

typedef struct logical_FAT12 logical_FAT12_t

typedef struct sector sector_t

typedef struct SectorDir SectorDir_t

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Function Documentation

bool cat (  char *    stringa )

Definition at line 388 of file fat12.c. { unsigned char Nome[9], Ext[4]; SectorDir_t *Buf, *Buf2; word sector; int counter; int h, i; bool a=FALSE; name_ext(stringa, Nome, Ext); counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); read_file((sector_t *)Buf, directory, counter); for(h=0; h<counter; h++) { for(i=0; i<FAT_SECTOR_SIZE/sizeof(FileEntry_t); i++) { a = compare_name_ext(Buf[h].Entry[i].Name, Nome, Buf[h].Entry[i].Extension, Ext); if (a) { // The file is empty // if ( !(Buf[h].Entry[i].StartCluster) ) goto founded; // Print the file to the standard output // sector = Buf[h].Entry[i].StartCluster; Buf2 = kmalloc(sizeof(sector_t)); memset(Buf2, 0, sizeof(sector_t)); for (;;) { read_file((sector_t *)Buf2, sector, 1); for (i=0; i<FAT_SECTOR_SIZE; i++) { kputchar( ((byte *)Buf2)[i] ); } if (!(next_sector(&sector, sector))) break; } kfree(Buf2); goto founded; } } } founded: kfree(Buf); if (!a) return(FALSE); return(TRUE); }

bool cd (  char *    new_path )

Definition at line 458 of file fat12.c. { int counter=0; int l, h, i; bool change=FALSE; word a=0; attrib_t FileAttr; char dir_name[8]; SectorDir_t *Buf; // Goto the root // if (new_path[0]=='/') if (new_path[1]=='\0') { path[0]='\0'; directory=0; return(TRUE); } counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); read_file((sector_t *)Buf, directory, counter); for(h=0; h<counter; h++) { for(i=0; i<FAT_SECTOR_SIZE/sizeof(FileEntry_t); i++) { read_attrib(&FileAttr, Buf[h].Entry[i].Attribute); if (FileAttr.Directory) { if ((Buf[h].Entry[i].Name[0]!=0)&&(Buf[h].Entry[i].Name[0]!=0xE5)) { if (Buf[h].Entry[i].Name[0]==5) Buf[h].Entry[i].Name[0]=0xE5; l=0; do { dir_name[l]=Buf[h].Entry[i].Name[l]; } while(dir_name[l++]!=' '); dir_name[--l]='\0'; if (strcmp(new_path, dir_name)==0) { a = Buf[h].Entry[i].StartCluster; change=TRUE; goto founded; } if (Buf[h].Entry[i].Name[0]==0xE5) Buf[h].Entry[i].Name[0]=0x05; } } } } founded: kfree(Buf); if (change) { directory = a; if (!a) path[0]='\0'; else { if(new_path[0] != '.') add_dir_path(new_path); else { if (new_path[1] == '.') up_dir_path(); } } return TRUE; } else return FALSE; }

int get_file_size (  char *    file_name )

Definition at line 311 of file fat12.c. { // Get the size of a file // unsigned char name[9], ext[4]; SectorDir_t *Buf; int counter, count=0, h, i; bool found=FALSE; // Get the file name and extension // name_ext(file_name, name, ext); // Get the list of file into the current directory // counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); // Read the directory // read_file((sector_t *)Buf, directory, counter); // Find the file // for(h=0; h<counter; h++) { for(i=0; i<FAT_SECTOR_SIZE/sizeof(FileEntry_t); i++) { found = compare_name_ext(Buf[h].Entry[i].Name, name, Buf[h].Entry[i].Extension, ext); if (found) { // The file is empty // if ( !(Buf[h].Entry[i].StartCluster) ) goto founded; // Get the size in clusters // count = how_many_cluster(Buf[h].Entry[i].StartCluster); goto founded; } } } founded: kfree(Buf); if (!found) return(-1); return(count*FAT_SECTOR_SIZE); };

bool load_file (  char *    stringa, byte *    buffer )

Definition at line 267 of file fat12.c. { unsigned char Nome[9], Ext[4]; SectorDir_t *Buf; int counter, count; int h, i; bool found=FALSE; // Get the file name and extension // name_ext(stringa, Nome, Ext); // Get the list of file into the current directory // counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); // Read the directory // read_file((sector_t *)Buf, directory, counter); for(h=0; h<counter; h++) { for(i=0; i<FAT_SECTOR_SIZE/sizeof(FileEntry_t); i++) { found = compare_name_ext(Buf[h].Entry[i].Name, Nome, Buf[h].Entry[i].Extension, Ext); if (found) { // The file is empty // if ( !(Buf[h].Entry[i].StartCluster) ) goto founded; // Copy the file into the buffer // count = how_many_cluster(Buf[h].Entry[i].StartCluster); read_file((sector_t *)buffer, Buf[h].Entry[i].StartCluster, count); goto founded; } } } founded: kfree(Buf); if (!found) return(FALSE); return(TRUE); }

void ls (    )

Definition at line 352 of file fat12.c. { int counter=0; int h, i, scroll; SectorDir_t *Buf; counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); read_file((sector_t *)Buf, directory, counter); kprintf("\nList of files into the directory:\n\r\n\r"); for(h=0, scroll=0; h<counter; h++) { for(i=0; i<(bootsector.BytesPerSector/sizeof(FileEntry_t)); i++) { if (scroll==20) { kprintf("\n\rPress a key to continue...\n\r"); scroll=0; if (kgetchar() == CTRL_C) { kprintf("\n\r"); kfree(Buf); return; } } if ( show_file_entry(&(Buf[h].Entry[i])) ) scroll++; } } kfree(Buf); kprintf("\n\r"); }

char* pwd (    )

Definition at line 452 of file fat12.c. { // Return the current path // return(path); }

bool Read_FAT (    )

Definition at line 673 of file fat12.c. { // Read the FAT from the floppy (mount) // int i, j; if (!( init_FAT() )) { kprintf("\n\rFloppy I/O error. Unable to read the block!!!\n\r"); return(FALSE); } // FAT initializazion OK! // for (i=0; i<3; i++) if (fdc_read(1, (byte *)&fat, bootsector.SectorsPerFat)) break; if (i == 3) { kprintf("\n\rFloppy I/O error. Unable to read the block!!!\n\r"); return(FALSE); } // Converts the FAT into the logical structures (array of word) // for(i=0, j=0; i<4608; i+=3) { lfat.data[j++] = (fat.data[i] + (fat.data[i+1] << 8)) & 0x0FFF; lfat.data[j++] = (fat.data[i+1] + (fat.data[i+2] << 8)) >> 4; } // Check if the FAT is correct // if (!( check_FAT() )) { kprintf("\n\rNot a valid FAT12 filesystem!!!\n\r"); return(FALSE); } // Initialize the path // path[0]='\0'; #ifdef FAT_DEBUG kprintf("\n\rInitializing FileSystem...\n\r"); kprintf("\n\r"); kprintf("Jump:\t\t\t%02x %02x %02x\n\r", bootsector.Jump[0], bootsector.Jump[1], bootsector.Jump[2]); kprintf("OS Name:\t\t\t%s\n\r", bootsector.Name); kprintf("BytesPerSector:\t\t\t%u\n\r", bootsector.BytesPerSector); kprintf("SectorsPerCluster:\t\t\t%u\n\r", bootsector.SectorsPerCluster); kprintf("ReservedSectors:\t\t\t%u\n\r", bootsector.ReservedSectors); kprintf("Fats:\t\t\t%u\n\r", bootsector.Fats); kprintf("RootDirectoryEntries:\t\t\t%u\n\r", bootsector.RootDirectoryEntries); kprintf("LogicalSectors:\t\t\t%u\n\r", bootsector.LogicalSectors); kprintf("MediumDescriptorByte:\t\t\t%X\n\r", bootsector.MediumDescriptorByte); kprintf("SectorsPerFat:\t\t\t%u\n\r", bootsector.SectorsPerFat); kprintf("SectorsPerTrack:\t\t\t%u\n\r", bootsector.SectorsPerTrack); kprintf("Heads:\t\t\t%u\n\r", bootsector.Heads); kprintf("HiddenSectors:\t\t\t%u\n\r", bootsector.HiddenSectors); kprintf("\n\r"); #endif return(TRUE); }

bool rm (  char *    filename )

Definition at line 606 of file fat12.c. { // Remove a file from the disk // unsigned char name[9], ext[4]; SectorDir_t *Buf; int counter, h, i; bool a=FALSE; if ( (strcmp(filename, ".")==0) || (strcmp(filename, "..")==0) ) return(FALSE); name_ext(filename, name, ext); counter = how_many_cluster(directory); Buf = kmalloc(FAT_SECTOR_SIZE*counter); memset(Buf, 0, FAT_SECTOR_SIZE*counter); read_file((sector_t *)Buf, directory, counter); for(h=0; h<counter; h++) { for(i=0; i<FAT_SECTOR_SIZE/sizeof(FileEntry_t); i++) { a = compare_name_ext(Buf[h].Entry[i].Name, name, Buf[h].Entry[i].Extension, ext); if (a) { // Delete the file // Buf[h].Entry[i].Name[0] = 0xE5; write_sector_dir(&Buf[h], h); delete_file(Buf[h].Entry[i].StartCluster); fat12_write(); goto founded; } } } founded: kfree(Buf); if (!a) return(FALSE); return(TRUE); }

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