\input texinfo @c -*-texinfo-*-
@c %**start of header
@setfilename libext2fs.info
-@settitle The EXT2FS Library (version 1.22)
+@settitle The EXT2FS Library (version 1.41.12)
@synindex tp fn
@comment %**end of header
@ifinfo
@dircategory Development
-@format
-START-INFO-DIR-ENTRY
-* libext2fs: (libext2fs.info). The EXT2FS library.
-END-INFO-DIR-ENTRY
-@end format
+@direntry
+* libext2fs: (libext2fs). The EXT2FS library.
+@end direntry
@end ifinfo
@c smallbook
This file documents the ext2fs library, a library for manipulating the
ext2 filesystem.
-Copyright (C) 1997, 1998, 1999, 2000, 2001 Theodore Ts'o
+Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+2006, 2007, 2008, 2009 by Theodore Ts'o
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
@title The EXT2FS Library
@subtitle The EXT2FS Library
-@subtitle Version 1.22
-@subtitle June 2001
+@subtitle Version 1.41.12
+@subtitle May 2010
@author by Theodore Ts'o
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1997, 1998, 1999, 2000, 2001 Theodore Ts'o
+Copyright @copyright{} 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
+2005 Theodore Ts'o
@sp 2
@top The EXT2FS Library
-This manual documents the EXT2FS Library, version 1.22.
+This manual documents the EXT2FS Library, version 1.41.12.
@end ifinfo
@menu
* Filesystem-level functions::
+* File I/O Functions::
* Inode Functions::
* Directory functions::
* Bitmap Functions::
@c ----------------------------------------------------------------------
-@node Filesystem-level functions, Inode Functions, EXT2FS Library Functions, EXT2FS Library Functions
+@node Filesystem-level functions, File I/O Functions, EXT2FS Library Functions, EXT2FS Library Functions
@comment node-name, next, previous, up
@section Filesystem-level functions
to be written when the filesystem is closed or flushed.
@end deftypefun
+@c ----------------------------------------------------------------------
+
+@node File I/O Functions, Inode Functions, Filesystem-level functions, EXT2FS Library Functions
+@comment node-name, next, previous, up
+@section File I/O Functions
+
+The following functions provide a convenient abstraction to read or
+write a file in an filesystem. The interface is similar in spirit to
+the Linux/POSIX file I/O system calls.
+@menu
+* File handle manipulation::
+* Reading and writing data::
+* Changing the file offset ::
+* Getting the file size::
+@end menu
@c ----------------------------------------------------------------------
-@node Inode Functions, Directory functions, Filesystem-level functions, EXT2FS Library Functions
+@node File handle manipulation, Reading and writing data, File I/O Functions, File I/O Functions
+@comment node-name, next, previous, up
+@subsection File handle manipulation
+
+The file handle functions much like a file descriptor in the Linux/POSIX
+file I/O system calls. Unlike the Linux/POSIX system calls, files are
+opened via inode numbers instead of via pathnames. To resolve a
+pathname to an inode number, use the function @code{ext2fs_namei} or to
+create a new file, use @code{ext2fs_new_inode} and @code{ext2fs_link}.
+
+@deftypefun errcode_t ext2fs_file_open2 (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, struct ext2_inode *@var{inode}, int @var{flags}, ext2_file_t *@var{ret})
+@deftypefunx errcode_t ext2fs_file_open (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, int @var{flags}, ext2_file_t *@var{ret})
+
+Opens a file identified by inode number @var{ino} in filesystem @var{fs}
+and returns a file handle in @var{ret}. If an inode structure is
+provided in @var{inode}, then it is used instead of reading the inode
+from the filesystem.
+
+The @var{flags} argument contains a bitmask of flags which control how
+the file should be opened.
+
+@table @code
+@item EXT2_FILE_WRITE
+Open the file for reading and writing. Without this flag, the file is
+opened for writing only.
+
+@item EXT2_FILE_CREATE
+Create the file if it is not already present.
+
+@end table
+@end deftypefun
+
+@deftypefun ext2_filsys ext2fs_file_get_fs (ext2_file_t @var{file})
+Return the filesystem handle where the open file @var{file} was opened.
+@end deftypefun
+
+@deftypefun errcode_t ext2fs_file_close (ext2_file_t @var{file})
+Close the file handle @var{file}.
+@end deftypefun
+
+@deftypefun errcode_t ext2fs_file_flush (ext2_file_t @var{file})
+Force any data written via @code{ext2fs_file_write} to disk.
+@end deftypefun
+
+@c ----------------------------------------------------------------------
+
+@node Reading and writing data, Changing the file offset , File handle manipulation, File I/O Functions
+@comment node-name, next, previous, up
+@subsection Reading and writing data
+
+@deftypefun errcode_t ext2fs_file_read (ext2_file_t @var{file}, void *@var{buf}, unsigned int @var{wanted}, unsigned int *@var{got})
+Read @var{wanted} bytes of data from @var{file} store it in the buffer
+@var{buf}. The number of bytes that was actually read is returned
+via @var{got}.
+@end deftypefun
+
+@deftypefun errcode_t ext2fs_file_write (ext2_file_t @var{file}, const void *@var{buf}, unsigned int @var{nbytes}, unsigned int *@var{written})
+Write @var{wanted} bytes of data from the buffer @var{buf} to the
+current file position of @var{file}. The number of bytes that was
+actually written is returned via @var{got}.
+@end deftypefun
+
+@c ----------------------------------------------------------------------
+
+@node Changing the file offset , Getting the file size, Reading and writing data, File I/O Functions
+@comment node-name, next, previous, up
+@subsection Changing the file offset
+
+@deftypefun errcode_t ext2fs_file_llseek (ext2_file_t @var{file}, __u64 @var{offset}, int @var{whence}, __u64 *@var{ret_pos})
+@deftypefunx errcode_t ext2fs_file_lseek (ext2_file_t @var{file}, ext2_off_t @var{offset}, int @var{whence}, ext2_off_t *@var{ret_pos})
+Change the current file position of @var{file} according to the
+directive @var{whence} as follows:
+
+@table @code
+@item EXT2_SEEK_SET
+The file position is set to @var{offset} bytes from the beginning of the
+file.
+
+@item EXT2_SEEK_CUR
+The file position set to its current location plus @var{offset} bytes.
+
+@item EXT2_SEEK_END
+The file position is set to the size of the file plus @var{offset}
+bytes.
+@end table
+
+The current offset is returned via @var{ret_pos}.
+@end deftypefun
+
+@c ----------------------------------------------------------------------
+
+@node Getting the file size, , Changing the file offset , File I/O Functions
+@comment node-name, next, previous, up
+@subsection Getting the file size
+
+@deftypefun errcode_t ext2fs_file_get_lsize (ext2_file_t @var{file}, __u64 *@var{ret_size})
+Return the size of the file @var{file} in @var{ret_size}.
+@end deftypefun
+
+@deftypefun ext2_off_t ext2fs_file_get_size (ext2_file_t @var{file})
+Return the size of the file @var{file}.
+@end deftypefun
+
+@c ----------------------------------------------------------------------
+
+@node Inode Functions, Directory functions, File I/O Functions, EXT2FS Library Functions
@comment node-name, next, previous, up
@section Inode Functions
Read the inode number @var{ino} into @var{inode}.
@end deftypefun
-@deftypefun errcode_t ext2fs_write_inode(ext2_filsys @var{fs}, ext2_ino_t @var{ino}, struct ext2_inode *@var{inode})
+@deftypefun errcode_t ext2fs_write_inode (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, struct ext2_inode *@var{inode})
Write @var{inode} to inode @var{ino}.
@end deftypefun
@subsection Iterating over blocks in an inode
@deftypefun errcode_t ext2fs_block_iterate (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, int @var{flags}, char *block_buf, int (*func)(ext2_filsys @var{fs}, blk_t *@var{blocknr}, int @var{blockcnt}, void *@var{private}), void *@var{private})
+
+Iterate over all of the blocks in inode number @var{ino} in filesystem
+@var{fs}, by calling the function @var{func} for each block in the
+inode. The @var{block_buf} parameter should either be NULL, or if the
+@code{ext2fs_block_iterate} function is called repeatedly, the overhead
+of allocating and freeing scratch memory can be avoided by passing a
+pointer to a scratch buffer which must be at least as big as three times the
+filesystem's blocksize.
+
+The @var{flags} parameter controls how the iterator will function:
+
+@table @samp
+
+@item BLOCK_FLAG_HOLE
+This flag indiciates that the interator function should be called on
+blocks where the block number is zero (also known as ``holes''.) It is
+also known as BLOCK_FLAG_APPEND, since it is also used by functions
+such as ext2fs_expand_dir() to add a new block to an inode.
+
+@item BLOCK_FLAG_DEPTH_TRAVERSE
+This flag indicates that the iterator function for the
+indirect, doubly indirect, etc. blocks should be called after all
+of the blocks containined in the indirect blocks are processed.
+This is useful if you are going to be deallocating blocks from an
+inode.
+
+@item BLOCK_FLAG_DATA_ONLY
+This flag indicates that the iterator function should be
+called for data blocks only.
+
+@end table
+
+The callback function @var{func} is called with a number of parameters;
+the @var{fs} and @var{private} parameters are self-explanatory, and
+their values are taken from the parameters to
+@code{ext2fs_block_iterate}. (The @var{private} data structure is
+generally used by callers to @code{ext2fs_block_iterate} so that some
+private data structure can be passed to the callback function. The
+@var{blockcnt} parameter, if non-negative, indicates the logical block
+number of a data block in the inode. If @var{blockcnt} is less than
+zero, then @var{func} was called on a metadata block, and @var{blockcnt}
+will be one of the following values: BLOCK_COUNT_IND, BLOCK_COUNT_DIND,
+BLOCK_COUNT_TIND, or BLOCK_COUNT_TRANSLATOR. The @var{blocknr} is a
+pointer to the inode or indirect block entry listing physical block
+number. The callback function may modify the physical block number, if
+it returns the @var{BLOCK_CHANGED} flag.
+
+
+The callback function @var{func} returns a result code which is composed of
+the logical OR of the following flags:
+
+@table @samp
+
+@item BLOCK_CHANGED
+
+This flag indicates that callback function has modified the physical
+block number pointed to by @var{blocknr}.
+
+@item BLOCK_ABORT
+
+This flag requests that @code{ext2fs_block_iterate} to stop immediately
+and return to the caller.
+
+@end table
+
@end deftypefun
@deftypefun errcode_t ext2fs_block_iterate2 (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, int @var{flags}, char *@var{block}_buf, int (*func)(ext2_filsys @var{fs}, blk_t *@var{blocknr}, e2_blkcnt_t @var{blockcnt}, blk_t @var{ref_blk}, int @var{ref_offset}, void *@var{private}), void *@var{private})
+
+This function is much like @code{ext2fs_block_iterate}, except that the
+@var{blockcnt} type is a 64-bit signed quantity, to support larger
+files, and the addition of the @var{ref_blk} and @var{ref_offset}
+arguments passed to the callback function, which identify the location
+of the physical block pointed to by pointer @var{blocknr}. If
+@var{ref_blk} is zero, then @var{ref_offset} contains the offset into
+the @code{i_blocks} array. If @var{ref_blk} is non-zero, then the physical
+block location is contained inside an indirect block group, and
+@var{ref_offset} contains the offset into the indirect block.
+
@end deftypefun
@c ----------------------------------------------------------------------
Returns 0 if @var{ino} is a directory, and @code{ENOTDIR} if it is not.
@end deftypefun
-@deftypefun int ext2_inode_has_valid_blocks (struct ext2_inode *@var{inode})
+@deftypefun int ext2fs_inode_has_valid_blocks (struct ext2_inode *@var{inode})
Returns 1 if the inode's block entries actually valid block entries, and
0 if not. Inodes which represent devices and fast symbolic links do not
@subsection Directory block functions
@deftypefun errcode_t ext2fs_read_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf})
+
+This function reads a directory block, performing any necessary
+byte swapping if necessary.
@end deftypefun
@deftypefun errcode_t ext2fs_write_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf})
+
+This function writes a directory block, performing any necessary
+byte swapping if necessary.
@end deftypefun
-@deftypefun errcode_t ext2fs_new_dir_block (ext2_filsys @var{fs}, ext2_ino_t @var{dir}_ino, ext2_ino_t @var{parent_ino}, char **@var{block})
+@deftypefun errcode_t ext2fs_new_dir_block (ext2_filsys @var{fs}, ext2_ino_t @var{dir_ino}, ext2_ino_t @var{parent_ino}, char **@var{block})
+
+This function creates a new directory block in @var{block}. If
+@var{dir_ino} is non-zero, then @var{dir_info} and @var{parent_ino} is used
+to initialize directory entries for @file{.} and @file{..}, respectively.
@end deftypefun
@c ----------------------------------------------------------------------
@subsection Iterating over a directory
@deftypefun errcode_t ext2fs_dir_iterate (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, int @var{flags}, char *@var{block_buf}, int (*@var{func})(struct ext2_dir_entry *@var{dirent}, int @var{offset}, int @var{blocksize}, char *@var{buf}, void *@var{private}), void *@var{private})
+
+This function interates over all of the directory entries in the
+directory @var{dir}, calling the callback function @var{func} for each
+directory entry in the directory. The @var{block_buf} parameter should
+either be NULL, or if the @code{ext2fs_dir_iterate} function is
+called repeatedly, the overhead of allocating and freeing
+scratch memory can be avoided by passing a pointer to a scratch buffer
+which must be at least as big as the filesystem's blocksize.
+
+The @var{flags} parameter controls how the iterator will function:
+
+@table @samp
+
+@item DIRENT_FLAG_INCLUDE_EMPTY
+
+This flag indicates that the callback function should be called even
+for deleted or empty directory entries.
+
+@end table
+
@end deftypefun
@c ----------------------------------------------------------------------
@subsection Creating and expanding directories
@deftypefun errcode_t ext2fs_mkdir (ext2_filsys @var{fs}, ext2_ino_t @var{parent}, ext2_ino_t @var{inum}, const char *@var{name})
+
+This function creates a new directory. If @var{inum} is zero, then a
+new inode will be allocated; otherwise, the directory will be created in
+the inode specified by @var{inum}. If @var{name} specifies the name of
+the new directory; if it is non-NULL, then the new directory will be
+linked into the parent directory @var{parent}.
@end deftypefun
@deftypefun errcode_t ext2fs_expand_dir (ext2_filsys @var{fs}, ext2_ino_t @var{dir})
+
+This function adds a new empty directory block and appends it to
+the directory @var{dir}. This allows functions such as
+@code{ext2fs_link} to add new directory entries to a directory which is full.
+
@end deftypefun
@c ----------------------------------------------------------------------
@subsection Creating and removing directory entries
@deftypefun errcode_t ext2fs_link (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, const char *@var{name}, ext2_ino_t @var{ino}, int flags)
+
+This function adds a new directory entry to the directory @var{dir},
+with @var{name} and @var{ino} specifying the name and inode number in
+the directory entry, respectively.
+
+The low 3 bits of the flags field is used to specify the file type of
+inode: (No other flags are currently defined.)
+
+@table @samp
+
+@item EXT2_FT_UNKNOWN
+
+The file type is unknown.
+
+@item EXT2_FT_REG_FILE
+
+The file type is a normal file.
+
+@item EXT2_FT_DIR
+
+The file type is a directory.
+
+@item EXT2_FT_CHRDEV
+
+The file type is a character device.
+
+@item EXT2_FT_BLKDEV
+
+The file type is a block device.
+
+@item EXT2_FT_FIFO
+
+The file type is a named pipe.
+
+@item EXT2_FT_SOCK
+
+The file type is a unix domain socket.
+
+@item EXT2_FT_SYMLINK
+
+The file type is a symbolic link.
+@end table
+
@end deftypefun
@deftypefun errcode_t ext2fs_unlink (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, const char *@var{name}, ext2_ino_t @var{ino}, int @var{flags})
+
+This function removes a directory entry from @var{dir}.
+The directory entry to be removed is the first one which is
+matched by @var{name} and @var{ino}. If @var{name} is non-NULL,
+the directory entry's name must match @var{name}. If @var{ino} is
+non-zero, the directory entry's inode number must match @var{ino}.
+No flags are currently defined for @code{ext2fs_unlink}; callers should
+pass in zero to this parameter.
+
@end deftypefun
@c ----------------------------------------------------------------------
@deftypefun blk_t ext2fs_get_block_bitmap_end (ext2fs_block_bitmap @var{bitmap})
@deftypefunx ext2_ino_t ext2fs_get_inode_bitmap_end (ext2fs_inode_bitmap @var{bitmap})
-Return the first inode or block which is stored in the bitmap.
+Return the last inode or block which is stored in the bitmap.
@end deftypefun
@subsection Clearing Bitmaps
@deftypefun void ext2fs_clear_inode_bitmap (ext2fs_inode_bitmap @var{bitmap})
+
+This function sets all of the bits in the inode bitmap @var{bitmap} to
+be zero.
+
@end deftypefun
@deftypefun void ext2fs_clear_block_bitmap (ext2fs_block_bitmap @var{bitmap})
+
+This function sets all of the bits in the block bitmap @var{bitmap} to
+be zero.
@end deftypefun
the inode is currrently not in use), and (2) many files have a inode
count of 1 (because they are a file which has no additional hard links).
-@deftypefun errcode_t ext2fs_create_icount2(ext2_filsys @var{fs}, int @var{flags}, int @var{size}, ext2_icount_t @var{hint}, ext2_icount_t *@var{ret})
+@deftypefun errcode_t ext2fs_create_icount2 (ext2_filsys @var{fs}, int @var{flags}, int @var{size}, ext2_icount_t @var{hint}, ext2_icount_t *@var{ret})
Creates an icount stucture for a filesystem @var{fs}, with initial space
for @var{size} inodes whose count is greater than 1. The @var{flags}
likely to contain a count grater than 1.
@end deftypefun
-@deftypefun void ext2fs_free_icount(ext2_icount_t @var{icount})
+@deftypefun void ext2fs_free_icount (ext2_icount_t @var{icount})
Frees an icount structure.
@end deftypefun
-@deftypefun errcode_t ext2fs_icount_fetch(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
+@deftypefun errcode_t ext2fs_icount_fetch (ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
Returns in @var{ret} fetches the count for a particular inode @var{ino}.
@end deftypefun
-@deftypefun errcode_t ext2fs_icount_increment(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
+@deftypefun errcode_t ext2fs_icount_increment (ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
Increments the ref count for inode @var{ino}.
@end deftypefun
-@deftypefun errcode_t ext2fs_icount_decrement(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
+@deftypefun errcode_t ext2fs_icount_decrement (ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret})
Decrements the ref count for inode @var{ino}.
@end deftypefun
-@deftypefun errcode_t ext2fs_icount_store(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 @var{count})
+@deftypefun errcode_t ext2fs_icount_store (ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 @var{count})
Sets the reference count for inode @var{ino} to be @var{count}.
@end deftypefun
-@deftypefun ext2_ino_t ext2fs_get_icount_size(ext2_icount_t @var{icount})
+@deftypefun ext2_ino_t ext2fs_get_icount_size (ext2_icount_t @var{icount})
Returns the current number of inodes in @var{icount} which has a count
greater than 1.
@end deftypefun
-@deftypefun errcode_t ext2fs_icount_validate(ext2_icount_t @var{icount}, FILE *@var{f})
+@deftypefun errcode_t ext2fs_icount_validate (ext2_icount_t @var{icount}, FILE *@var{f})
Validates the internal rep invariant of @var{icount}; if there are any
problems, print out debugging information to @var{f}. This function is
@deftypefun errcode_t ext2fs_check_desc (ext2_filsys @var{fs})
@end deftypefun
-@deftypefun errcode_t ext2_get_num_dirs (ext2_filsys @var{fs}, ext2_ino_t *@var{ret_num_dirs})
+@deftypefun errcode_t ext2fs_get_num_dirs (ext2_filsys @var{fs}, ext2_ino_t *@var{ret_num_dirs})
@end deftypefun
/* version.c */
-@deftypefun int ext2fs_get_library_version(const char **@var{ver_string}, const char **@var{date_string})
+@deftypefun int ext2fs_get_library_version (const char **@var{ver_string}, const char **@var{date_string})
This function returns the current version of the ext2 library. The
return value contains an integer version code, which consists of the
release date, respectively.
@end deftypefun
-@deftypefun int ext2fs_parse_version_string(const char *@var{ver_string})
+@deftypefun int ext2fs_parse_version_string (const char *@var{ver_string})
This function takes a version string which may included in an
application and returns a version code using the same algorithm used by
/* inline functions */
@deftypefun int ext2fs_group_of_blk (ext2_filsys @var{fs}, blk_t @var{blk})
+
+This function returns the block group which contains the block @var{blk}.
+
@end deftypefun
@deftypefun int ext2fs_group_of_ino (ext2_filsys @var{fs}, ext2_ino_t @var{ino})
+
+This function returns the block group which contains the inode @var{ino}.
@end deftypefun
projects / thirdparty / e2fsprogs.git / blobdiff