src/filesys/filesys.c

   1 #include "filesys/filesys.h"
   2 #include <debug.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include "filesys/file.h"
   6 #include "filesys/free-map.h"
   7 #include "filesys/inode.h"
   8 #include "filesys/directory.h"
   9 #include "devices/disk.h"
  10
  11 /* The disk that contains the file system. */
  12 struct disk *filesys_disk;
  13
  14 static void do_format (void);
  15
  16 /* Initializes the file system module.
  17    If FORMAT is true, reformats the file system. */
  18 void
  19 filesys_init (bool format)
  20 {
  21   filesys_disk = disk_get (0, 1);
  22   if (filesys_disk == NULL)
  23     PANIC ("hd0:1 (hdb) not present, file system initialization failed");
  24
  25   inode_init ();
  26   free_map_init ();
  27
  28   if (format)
  29     do_format ();
  30
  31   free_map_open ();
  32 }
  33
  34 /* Shuts down the file system module, writing any unwritten data
  35    to disk. */
  36 void
  37 filesys_done (void)
  38 {
  39   free_map_close ();
  40 }
  41 \f
  42 /* Creates a file named NAME with the given INITIAL_SIZE.
  43    Returns true if successful, false otherwise.
  44    Fails if a file named NAME already exists,
  45    or if internal memory allocation fails. */
  46 bool
  47 filesys_create (const char *name, off_t initial_size)
  48 {
  49   disk_sector_t inode_sector = 0;
  50   struct dir *dir = dir_open_root ();
  51   bool success = (dir != NULL
  52                   && free_map_allocate (1, &inode_sector)
  53                   && inode_create (inode_sector, initial_size)
  54                   && dir_add (dir, name, inode_sector));
  55   if (!success && inode_sector != 0)
  56     free_map_release (inode_sector, 1);
  57   dir_close (dir);
  58
  59   return success;
  60 }
  61
  62 /* Opens the file with the given NAME.
  63    Returns the new file if successful or a null pointer
  64    otherwise.
  65    Fails if no file named NAME exists,
  66    or if an internal memory allocation fails. */
  67 struct file *
  68 filesys_open (const char *name)
  69 {
  70   struct dir *dir = dir_open_root ();
  71   struct inode *inode = NULL;
  72
  73   if (dir != NULL)
  74     dir_lookup (dir, name, &inode);
  75   dir_close (dir);
  76
  77   return file_open (inode);
  78 }
  79
  80 /* Deletes the file named NAME.
  81    Returns true if successful, false on failure.
  82    Fails if no file named NAME exists,
  83    or if an internal memory allocation fails. */
  84 bool
  85 filesys_remove (const char *name)
  86 {
  87   struct dir *dir = dir_open_root ();
  88   bool success = dir != NULL && dir_remove (dir, name);
  89   dir_close (dir);
  90
  91   return success;
  92 }
  93 \f
  94 /* Formats the file system. */
  95 static void
  96 do_format (void)
  97 {
  98   printf ("Formatting file system...");
  99   free_map_create ();
 100   if (!dir_create (ROOT_DIR_SECTOR, 16))
 101     PANIC ("root directory creation failed");
 102   free_map_close ();
 103   printf ("done.\n");
 104 }