scripts/gdb: add GDB convenience functions $lx_dentry_name() and $lx_i_dentry()

# This work is licensed under the terms of the GNU GPL version 2.

#

import gdb

from linux import utils

def dentry_name(d):

    parent = d['d_parent']

        return ""

    p = dentry_name(d['d_parent']) + "/"

    return p + d['d_iname'].string()

class DentryName(gdb.Function):

    """Return string of the full path of a dentry.

$lx_dentry_name(PTR): Given PTR to a dentry struct, return a string

of the full path of the dentry."""

    def __init__(self):

        super(DentryName, self).__init__("lx_dentry_name")

    def invoke(self, dentry_ptr):

        return dentry_name(dentry_ptr)

DentryName()

dentry_type = utils.CachedType("struct dentry")

class InodeDentry(gdb.Function):

    """Return dentry pointer for inode.

$lx_i_dentry(PTR): Given PTR to an inode struct, return a pointer to

the associated dentry struct, if there is one."""

    def __init__(self):

        super(InodeDentry, self).__init__("lx_i_dentry")

    def invoke(self, inode_ptr):

        d_u = inode_ptr["i_dentry"]["first"]

        if d_u == 0:

            return ""

        return utils.container_of(d_u, dentry_type.get_type().pointer(), "d_u")

InodeDentry()