Ifile Functions

The ifile module provides methods for opening and reading Filesystem objects by inode number.

These methods could be used to make backups of a Filesystem or iterate selective areas of the Filesystem.

Note

These objects require root permission to create

Description

direntx struct

The direntx struct returned by ireaddir() has the following fields

d_type         # Type (int) - can be converted with 'get_type_string'
d_ino          # File inode number (int)
d_gen          # Generation number for the inode (int)
d_flags        # Flags (int) - can be converted with 'get_flags_strings'
d_name         # File name (str)

arcapix.fs.gpfs.clib.ifile.get_flags_strings(unsigned int flags)

Get strings for direntx flags integer.

Used to convert the d_flags value of direntx as returned by ireaddir`()

Returns: One or more of (JUNCTION, IJUNCTION, ORPHAN, CLONE, NONE)
Return type: list of str

arcapix.fs.gpfs.clib.ifile.get_type_string(int type)

Get the type string for a direntx type integer.

Used to convert the d_type value of direntx as returned by ireaddir`()

Returns: One of (REG, DIR, LNK, DEL, FIFO, CHR, BLK, SOCK, OTHER)
Return type: str

arcapix.fs.gpfs.clib.ifile.iclose(ifile file)

Close an ifile object.

Parameters: file – ifile to close

class arcapix.fs.gpfs.clib.ifile.ifile: The ifile object acts as a wrapper for the gpfs_ifile_t pointer.

arcapix.fs.gpfs.clib.ifile.iopen(fssnap_handle fssnap, gpfs_ino64_t ino, int flags=0)

Open an ifile object for the given inode.

Parameters

fsnap (fssnap_handle) – fssnap handle identifying a filesystem or snapshot
ino (int) – Inode number of the file object to open
flags (int) – flags indicating open mode (default=0, readonly)

Returns

an open ifile object

Return type

ifile

arcapix.fs.gpfs.clib.ifile.iread(ifile file, int buffersize, gpfs_off64_t offset=0)

Read bytes from an open ifile.

Parameters

file – ifile to read from. This should correspond to a regular file.
buffersize (int) – number of bytes to read
offset (int) – offset in file to start reading from (in bytes)

Returns

bytes read

Return type

bytes

arcapix.fs.gpfs.clib.ifile.ireaddir(ifile idir)

Read entries from a directory.

This method can be used to iterate over the file objects in a directory.

>>> for ent in iter(lambda: ireaddir(idir), None):
...     # do stuff

Parameters: idir – ifile to read from. This should correspond to a directory.
Returns: a directory entry representing a file in the directory
Return type: direntx

arcapix.fs.gpfs.clib.ifile.ireadlink(fssnap_handle fssnap, gpfs_ino64_t ino)

Get the target of a Symlink by inode number.

Parameters

fssnap (fssnap_handle) – Filesystem of snapshot to look in
ino (int) – inode number of the symlink to read

Return type

str

Examples

Print a list of objects in a directory

>>> from arcapix.fs.gpfs.clib.fssnap import get_fssnaphandle_by_name
>>> from arcapix.fs.gpfs.clib.ifile import iopen, ireaddir, ireadlink, iclose, DE_LNK
>>>
>>> # Create handle
... fs = get_fssnaphandle_by_name('mmfs1')
>>>
>>> # Open directory; inode 3 = fs root directory
... d = iopen(fs, 3)
>>>
>>> # iterate over contents
... for f in iter(lambda: ireaddir(d), None):
...     # if symlink, print target
...     if f.d_type == DE_LNK:
...         print("%s\t%s -> %s" % (f.d_ino, f.d_name, ireadlink(fs, f.d_ino)))
...     else:
...         print("%s\t%s" % (f.d_ino, f.d_name))
3        .
3        ..
39173    link -> /mmfs1/test
16134    test
18177    data
18176    .policytmp

>>> # close idir
... iclose(d)