e2fsprogs/ext2fs/ext2_io.h

   1 /*
   2  * io.h --- the I/O manager abstraction
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #ifndef _EXT2FS_EXT2_IO_H
  13 #define _EXT2FS_EXT2_IO_H
  14
  15 /*
  16  * ext2_loff_t is defined here since unix_io.c needs it.
  17  */
  18 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
  19 typedef long long       ext2_loff_t;
  20 #else
  21 typedef long            ext2_loff_t;
  22 #endif
  23
  24 /* llseek.c */
  25 /* ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int); */
  26 #ifdef CONFIG_LFS
  27 # define ext2fs_llseek lseek64
  28 #else
  29 # define ext2fs_llseek lseek
  30 #endif
  31
  32 typedef struct struct_io_manager *io_manager;
  33 typedef struct struct_io_channel *io_channel;
  34
  35 #define CHANNEL_FLAGS_WRITETHROUGH      0x01
  36
  37 struct struct_io_channel {
  38         errcode_t       magic;
  39         io_manager      manager;
  40         char            *name;
  41         int             block_size;
  42         errcode_t       (*read_error)(io_channel channel,
  43                                       unsigned long block,
  44                                       int count,
  45                                       void *data,
  46                                       size_t size,
  47                                       int actual_bytes_read,
  48                                       errcode_t error);
  49         errcode_t       (*write_error)(io_channel channel,
  50                                        unsigned long block,
  51                                        int count,
  52                                        const void *data,
  53                                        size_t size,
  54                                        int actual_bytes_written,
  55                                        errcode_t error);
  56         int             refcount;
  57         int             flags;
  58         int             reserved[14];
  59         void            *private_data;
  60         void            *app_data;
  61 };
  62
  63 struct struct_io_manager {
  64         errcode_t magic;
  65         const char *name;
  66         errcode_t (*open)(const char *name, int flags, io_channel *channel);
  67         errcode_t (*close)(io_channel channel);
  68         errcode_t (*set_blksize)(io_channel channel, int blksize);
  69         errcode_t (*read_blk)(io_channel channel, unsigned long block,
  70                               int count, void *data);
  71         errcode_t (*write_blk)(io_channel channel, unsigned long block,
  72                                int count, const void *data);
  73         errcode_t (*flush)(io_channel channel);
  74         errcode_t (*write_byte)(io_channel channel, unsigned long offset,
  75                                 int count, const void *data);
  76         errcode_t (*set_option)(io_channel channel, const char *option,
  77                                 const char *arg);
  78         int             reserved[14];
  79 };
  80
  81 #define IO_FLAG_RW      1
  82
  83 /*
  84  * Convenience functions....
  85  */
  86 #define io_channel_close(c)             ((c)->manager->close((c)))
  87 #define io_channel_set_blksize(c,s)     ((c)->manager->set_blksize((c),s))
  88 #define io_channel_read_blk(c,b,n,d)    ((c)->manager->read_blk((c),b,n,d))
  89 #define io_channel_write_blk(c,b,n,d)   ((c)->manager->write_blk((c),b,n,d))
  90 #define io_channel_flush(c)             ((c)->manager->flush((c)))
  91 #define io_channel_bumpcount(c)         ((c)->refcount++)
  92
  93 /* io_manager.c */
  94 extern errcode_t io_channel_set_options(io_channel channel,
  95                                         const char *options);
  96 extern errcode_t io_channel_write_byte(io_channel channel,
  97                                        unsigned long offset,
  98                                        int count, const void *data);
  99
 100 /* unix_io.c */
 101 extern io_manager unix_io_manager;
 102
 103 /* test_io.c */
 104 extern io_manager test_io_manager, test_io_backing_manager;
 105 extern void (*test_io_cb_read_blk)
 106         (unsigned long block, int count, errcode_t err);
 107 extern void (*test_io_cb_write_blk)
 108         (unsigned long block, int count, errcode_t err);
 109 extern void (*test_io_cb_set_blksize)
 110         (int blksize, errcode_t err);
 111
 112 #endif /* _EXT2FS_EXT2_IO_H */
 113