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Changes between Version 18 and Version 19 of file_system

Timestamp:: Jul 8, 2015, 7:00:52 PM (9 years ago)
Author:: alain
Comment:: --

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: Unmodified
: Added
: Removed
: Modified

file_system

-                      v18
+                      v19
 for each modified cluster.
+== 4) Access Functions ==
+=== int '''_fat_init'''( unsigned int kernel_mode ) ===
+== 4) Extern Functions ==
+The following functions implement the FAT related system calls.
+=== __int '''_fat_init'''( unsigned int kernel_mode )__ ===
 This function initializes the  FAT structures. It is called twice, by the boot-loader, and by the kernel_init.
  *  in '''boot mode''' (kernel_mode == 0), it initialises only the statically defined Fat-Descriptor, using informations found in the boot sector and FS-INFO sector, that are loaded in the FAT descriptor 512 bytes buffer. In this mode, it is used by the boot code to load the ''kernel.elf'' file, and the various ''application.elf'' files,
 …
 It returns 0 if success /  It returns -1 if failure.
 === int '''_fat_open'''( char* pathname , unsigned int flags ) ===
+=== __int '''_fat_open'''( char* pathname , unsigned int flags )__ ===
 This function implements the giet_fat_open() system call.
 The semantic is similar to the UNIX open() function,  but only the O_CREATE
 …
  *   -9  :  "file descriptor array full"
 === int '''_fat_close'''( unsigned int fd_id  ) ===
+=== __int '''_fat_close'''( unsigned int fd_id  )__ ===
 This function implements the "giet_fat_close()" system call.
 The semantic is similar to the UNIX "close()" function.
 …
  *  -4  : "Cannot release memory"
 === int '''_fat_file_info'''( unsigned int fd_id , unsigned int* size , unsigned int* offset ) ===
+=== __int '''_fat_file_info'''( unsigned int fd_id , unsigned int* size , unsigned int* offset )__ ===
 This function implements the giet_fat_file_info() system call.
 It returns the size and the current offset value for a file identified  by the "fd_id" argument.
 …
  *  -3  : "File not open"
 === int '''_fat_read'''( unsigned int fd_id , void* buffer , unsigned int count ) ===
+=== __int '''_fat_read'''( unsigned int fd_id , void* buffer , unsigned int count )__ ===
 This function implements the "giet_fat_read()" system call.
 It access the File-Cache  associated to the file identified by the file descriptor, and transfers "count" bytes from the cache to the user buffer, starting from the current file offset.
 …
  *  -2  : "Illegal file descriptor"
  *  -3  : "File not open"
  *  -4  : "Cannot load
 === int '''_fat_write'''( unsigned int fd_id , void* buffer , unsigned int count ) ===
 This function implements the "giet_fat_write()" system call, that has the same semantic as the UNIX "write()" function.
+ *  -4  : "Cannot load file from device"
+=== __int '''_fat_write'''( unsigned int fd_id , void* buffer , unsigned int count )__ ===
+This function implements the "giet_fat_write()" system call.
 It access the File-Cache associated to the file identified by the file descriptor, and transfers count bytes from the user buffer,
 to the cache, starting from the current file offset. It loads all involved clusters into cache if required. If (offset + count) is larger than the current file size, it increases the file size. It allocates new clusters if required, and updates the Fat-Cache and the FAT region on block device. As it implements a Write-Back policy, the DATA region on block device is not updated, but the modified clusters are marked dirty.
 …
  * '''buffer''' : pointer on the memory buffer
  * '''count''' : number of bytes
+It returns the number of bytes actually transfered if success / It returns -1 if failure.
+=== int '''_fat_lseek'''( unsigned int fd_id , unsigned int offset , unsigned int whence ) ===
+This function implements the "giet_fat_lseek()" system call, that has the same semantic as the UNIX ''seek()'' function.
+It returns the number of bytes actually transfered if success. It returns a negative value if error.
+ *   -1 :  "FAT not initialised"
+ *   -2 :  "Illegal file descriptor"
+ *   -3 :  "File not open"
+ *   -4 :  "File not writable"
+ *   -5 :  "No free clusters"
+ *   -6 :  "Cannot update parent directory entry"
+ *   -7 :  "Cannot access File-Cache"
+=== __int '''_fat_lseek'''( unsigned int fd_id , unsigned int offset , unsigned int whence )__ ===
+This function implements the "giet_fat_lseek()" system call.
 It repositions the offset in the file defined by the file descriptor, according to the offset and whence arguments.
 The accepted values for the whence argument are SEEK_SET and SEEK_CUR:
 …
  * '''offset''' : pointer on the memory buffer
  * '''count''' : number of bytes
+It returns new offset value (bytes) if success / It returns -1 if failure.
+=== int '''_fat_mkdir'''( char* pathname ) ===
+It returns new offset value (bytes) if success. It returns a negative value if error:
+ *   -1  : "FAT not initialised"
+ *   -2  : "Illegal file descriptor"
+ *   -3  : "File not open"
+ *   -4  : "Illegal whence argument"
+=== __int '''_fat_mkdir'''( char* pathname )__ ===
 This function implements the giet_fat_mkdir() system call, that has the same semantic as the UNIX ''mkdir()'' function.
 It creates a new directory in the File System as specified by the pathname argument.
 …
 The Inode-Tree is updated.
  * '''pathname''' : complete pathname
+It returns 0 if success /  It returns -1 if failure.
+=== int '''_fat_unlink'''( char* pathname ) ===
+It returns 0 if success.  It returns a negative value if error:
+ *   -1  : "Fat not initialised"
+ *   -2  : "Path to parent not found"
+ *   -3  : "One name in path too long"
+ *   -4  : "Directory already exist"
+ *   -5  : "No free cluster"
+ *   -6  : "Cannot update parent directory"
+ *   -7  : "Cannot update parent DATA region"
+ *   -8  : "Cannot update FAT region"
+ *   -9  : "Cannot update FS-INFO"
+ *   -10 : "Cannot update directory DATA region"
+=== __int '''_fat_remove'''( char* pathname , unsigned int should_be_dir )__ ===
 This function implements the giet_fat_unlink() system call, that has the same semantic as the UNIX ''unlink()'' function.
 It removes the file identified by the pathname argument from the File System. An error is returned if the number of references
 …
 The Inode-Tree is updated.
  * '''pathname''' : directory complete pathname
+It returns 0 if success /  It returns -1 if failure.
+=== int '''_fat_read_no_cache'''( char* pathname , unsigned int buffer_vbase , unsigned int buffer_size ) ===
+It returns 0 if success.  It returns a negative value if error:
+ *   -1  : "FAT not initialised"
+ *   -2  : "File/Directory not found"
+ *   -3  : "Name too long in path"
+ *   -4  : "Has the wrong type"
+ *   -5  : "File still open"
+ *   -6  : "Cannot scan directory"
+ *   -7  : "Directory not empty"
+ *   -8  : "Cannot remove file/dir from FS"
+=== __int _fat_rename( char* old_path , new_path )__ ===
+This function implements the giet_fat_rename() system call.
+It moves an existing file or directory from one node (defined by "old_path"
+argument) to another node (defined by "new_path" argument) in the FS tree.
+The type (file/directory) and content are not modified.
+If the new_path file/dir exist, it is removed from the file system, but only
+if the remove condition is respected (directory empty / file not referenced).
+The removed entry is only removed after the new entry is actually created.
+ * '''old_path''' : old path-name (from root).
+ * '''new_path''' : new path-name (from root).
+It returns 0 if success.  It returns a negative value if error:
+ *  -1  : "FAT not initialised"
+ *  -2  : "old_path not found"
+ *  -3  : "new_path not found"
+ *  -4  : "cannot  scan to_remove directory"
+ *  -5  : "to_remove directory not empty"
+ *  -6  : "to_remove file still referenced"
+ *  -7  : "cannot add new node to new_parent directory"
+ *  -8  : "cannot update new_parent directory on device"
+ *  -9  : "cannot remove old node from old_parent directory"
+ *  -10 : "cannot update old_parent directory on device"
+ *  -11 : "cannot remove to_remove node from FS"
+=== __int '''_fat_list'''( char* pathname )__ ===
+This function implements the giet_fat_list() system call.
+It displays the content of a directory identified by the pathname argument.
+It returns 0 if success. It returns a negative value if error:
+ *   -1  : "FAT not initialised
+ *   -2  : "Directory not found"
+ *   -3  : "Name in path too long
+ *   -4  : "Not a directory"
+ *   -5  : "Cannot access directory"
+=== __int '''_fat_read_no_cache'''( char* pathname , unsigned int buffer_vbase , unsigned int buffer_size )__ ===
 This functiond load a file identified by the pathname argument into the memory buffer defined by the buffer_vbase / buffer_size arguments. It is intended to be called by the boot-loader, as it uses neither the dynamically allocated FAT structures (Inode-Tree, Fat_Cache or File-Cache), nor the File-Descriptor-Array. It uses only the 4096 bytes buffer defined in the FAT descriptor.
  * '''pathname''' : file complete pathname
  * '''buffer_vbase''' : memory buffer virtual address
  * '''buffer_size''' : buffer size (bytes)
+It returns 0 if success / It returns -1 if failure.
+=== int '''_fat_ioc_access'''( unsigned int use_irq ,  unsigned int to_mem ,  unsigned int lba , unsigned int buf_vaddr , unsigned int count ) ===
+It returns 0 if success. It returns a negative value if error.
+ *  -1  : "FAT not initialised"
+ *  -2  : "File not found"
+ *  -3  : "Buffer too small"
+ *  -4  : "Cannot access block device"
+ *  -5  : "Cannot access FAT on block device"
+== 5) Internal functions ==
+The following functions can be used to implement new system calls if required.
+=== __int '''_fat_ioc_access'''( unsigned int use_irq ,  unsigned int to_mem ,  unsigned int lba , unsigned int buf_vaddr , unsigned int count )__ ===
 This function transfer one or several blocks between the block device and a memory buffer by calling the relevant driver.
  * '''use_irq''' : boolean (use descheduling mode if supported by the IOC driver)