Correct loading of master table from MBR

lsfs_disk_controller.h

@@ -46,6 +46,7 @@ int save_modified_file_information(lsfs_file* file);
 
 
 #define SECTOR_SIZE 512
+#define NUMBER_OF_MBR_PARTITIONS 4
 #define DEFAULT_FILE_SIZE 4 // This is in sectors
 #define DEFAULT_MASTER_TABLE_SIZE 64 
 #define DEFAULT_TAG_TABLE_SIZE 64 // correspond to 262144 bytes in sectors - 16384 files pr. default. (minus one, the last is a pointer to a table more )
@@ -62,6 +63,23 @@ typedef struct struct_partition_control{
     table_entry*     master_table;
 } __attribute__((packed)) partition_control;
 
+typedef struct Partition_Entry
+{
+    uint8_t  active_falg; // This has value 0x80 if it is a bootable partition / it is an active partition. 
+    uint8_t  CHS_start_addr[3]; // [0] = H, [1] = S, [2] = C 
+    uint8_t  partition_type; // This has a value such that one can idenfity which file system the partition is. 
+    uint8_t  CHS_last_addr[3]; // [0] = H, [1] = S, [2] = C
+    uint32_t LBA_abs_first_sector;
+    uint32_t number_of_sectors;
+
+} __attribute__((packed)) Partition_Entry;
+
+typedef struct Master_Boot_record {
+    uint8_t            offset_on_disk[446]; // The code for the bootloader 
+    Partition_Entry    partitions[4];
+    uint8_t    master_tag_records[2]; // Signature
+} __attribute__((packed)) Master_Boot_record;
+
 typedef struct File_System_Control_Information {
     uint64_t    offset_on_disk;
     uint64_t    next_partition;
@@ -82,7 +100,7 @@ typedef struct struct_table_entry {
     struct {
         uint32_t is_filename : 1;    
     } control_bits;
-    lsfs_sector_offset data_pointer[NUM_DATA_POINTERS]
+    lsfs_sector_offset data_pointer[NUM_DATA_POINTERS];
 } __attribute__((packed)) table_entry; 
 
 
@@ -237,7 +255,6 @@ time_t lsfs_disk_truncate_file(lsfs_file *file, off_t offset) {
     //read_data_from_disk(file_id, &file_mif);
     
     time_t result = lsfs_disk_update_timestamps(file);
-
     file->size = (int) offset; // p_control.master_table[i].data_pointer[0]; //;
 
     save_modified_file_information(file);
@@ -515,16 +532,26 @@ int create_file_system() {
 }
 
 int lsfs_disk_load_disk() {
-    
-    // First we find the Mater Table.     
-    fseek ( disk , 24 * SECTOR_SIZE, SEEK_SET );
-    fread(p_control.master_table, 1, sizeof(table_entry) * DEFAULT_MASTER_TABLE_SIZE , disk);
-
-    // Now we can finde the FSCI data
-    //fseek ( disk , 0, SEEK_SET );
-    //fread(p_control.fsci, 1, sizeof(FSCI), disk);
-
-    return 1;
+    // Find the partition talbe: 
+    // This makes is BIOS dependent. 
+    // UEFI is not supported. 
+    Master_Boot_record mbr;
+    fseek( disk , 0 * SECTOR_SIZE, SEEK_SET );
+    fread(&mbr, 1, sizeof(mbr), disk);
+
+    for (int i = 0; i < NUMBER_OF_MBR_PARTITIONS; ++i)
+    {
+        // TODO (Jørn) We maybe wnat to optimize, such that we can detect if we have more than one partition opn the system. 
+        if (mbr.partitions[i].partition_type == 0x18)
+        {
+            printf("%d\n", mbr.partitions[i].LBA_abs_first_sector);
+            // First we find the Mater Table. 
+            fseek ( disk , mbr.partitions[i].LBA_abs_first_sector * SECTOR_SIZE, SEEK_SET );
+            fread(p_control.master_table, 1, sizeof(table_entry) * DEFAULT_MASTER_TABLE_SIZE , disk);
+            return 1;
+        }
+    }
+    return 0; 
 }
 
 

lsfs_fuse.c

@@ -305,6 +305,7 @@ int lsfs_mknod(const char *path, mode_t mode, dev_t device) {
 end:
     lsfs_destroy_string_array(split_path);
     return res;*/
+    return 0;
 }
 
 int main( int argc, char *argv[] ) {
@@ -312,14 +313,13 @@ int main( int argc, char *argv[] ) {
     disk = fopen ("/home/rhodez-x/Documents/github/SingOS/SingOS.img", "r+b");
     p_control.fsci = malloc(sizeof(FSCI));
     p_control.master_table = malloc(sizeof(table_entry) * DEFAULT_MASTER_TABLE_SIZE);
-    lsfs_disk_load_disk();
-    
-    //tag_record *tag_table = calloc(1, SECTOR_SIZE);
-    //mif* mif_data = calloc(1, SECTOR_SIZE);
-
-    //free(mif_data);
-    //free(tag_table);
-    //free(seen_file_ids);
-
-    return fuse_main( argc, argv, &lsfs_oper );
+    if (lsfs_disk_load_disk()) 
+    {
+        return fuse_main( argc, argv, &lsfs_oper );
+    }
+    else 
+    {
+        printf("[ERROR] - Correct file format not found \n");
+        return 0;
+    }
 }