271 lines
8.4 KiB
Python
271 lines
8.4 KiB
Python
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#
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# gdb helper commands and functions for Linux kernel debugging
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#
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# Kernel proc information reader
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#
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# Copyright (c) 2016 Linaro Ltd
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#
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# Authors:
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# Kieran Bingham <kieran.bingham@linaro.org>
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#
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# This work is licensed under the terms of the GNU GPL version 2.
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#
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import gdb
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from linux import constants
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from linux import utils
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from linux import tasks
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from linux import lists
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from struct import *
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class LxCmdLine(gdb.Command):
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""" Report the Linux Commandline used in the current kernel.
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Equivalent to cat /proc/cmdline on a running target"""
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def __init__(self):
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super(LxCmdLine, self).__init__("lx-cmdline", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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gdb.write(gdb.parse_and_eval("saved_command_line").string() + "\n")
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LxCmdLine()
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class LxVersion(gdb.Command):
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""" Report the Linux Version of the current kernel.
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Equivalent to cat /proc/version on a running target"""
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def __init__(self):
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super(LxVersion, self).__init__("lx-version", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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# linux_banner should contain a newline
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gdb.write(gdb.parse_and_eval("(char *)linux_banner").string())
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LxVersion()
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# Resource Structure Printers
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# /proc/iomem
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# /proc/ioports
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def get_resources(resource, depth):
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while resource:
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yield resource, depth
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child = resource['child']
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if child:
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for res, deep in get_resources(child, depth + 1):
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yield res, deep
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resource = resource['sibling']
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def show_lx_resources(resource_str):
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resource = gdb.parse_and_eval(resource_str)
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width = 4 if resource['end'] < 0x10000 else 8
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# Iterate straight to the first child
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for res, depth in get_resources(resource['child'], 0):
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start = int(res['start'])
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end = int(res['end'])
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gdb.write(" " * depth * 2 +
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"{0:0{1}x}-".format(start, width) +
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"{0:0{1}x} : ".format(end, width) +
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res['name'].string() + "\n")
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class LxIOMem(gdb.Command):
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"""Identify the IO memory resource locations defined by the kernel
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Equivalent to cat /proc/iomem on a running target"""
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def __init__(self):
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super(LxIOMem, self).__init__("lx-iomem", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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return show_lx_resources("iomem_resource")
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LxIOMem()
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class LxIOPorts(gdb.Command):
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"""Identify the IO port resource locations defined by the kernel
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Equivalent to cat /proc/ioports on a running target"""
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def __init__(self):
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super(LxIOPorts, self).__init__("lx-ioports", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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return show_lx_resources("ioport_resource")
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LxIOPorts()
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# Mount namespace viewer
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# /proc/mounts
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def info_opts(lst, opt):
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opts = ""
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for key, string in lst.items():
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if opt & key:
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opts += string
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return opts
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FS_INFO = {constants.LX_MS_SYNCHRONOUS: ",sync",
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constants.LX_MS_MANDLOCK: ",mand",
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constants.LX_MS_DIRSYNC: ",dirsync",
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constants.LX_MS_NOATIME: ",noatime",
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constants.LX_MS_NODIRATIME: ",nodiratime"}
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MNT_INFO = {constants.LX_MNT_NOSUID: ",nosuid",
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constants.LX_MNT_NODEV: ",nodev",
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constants.LX_MNT_NOEXEC: ",noexec",
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constants.LX_MNT_NOATIME: ",noatime",
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constants.LX_MNT_NODIRATIME: ",nodiratime",
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constants.LX_MNT_RELATIME: ",relatime"}
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mount_type = utils.CachedType("struct mount")
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mount_ptr_type = mount_type.get_type().pointer()
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class LxMounts(gdb.Command):
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"""Report the VFS mounts of the current process namespace.
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Equivalent to cat /proc/mounts on a running target
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An integer value can be supplied to display the mount
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values of that process namespace"""
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def __init__(self):
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super(LxMounts, self).__init__("lx-mounts", gdb.COMMAND_DATA)
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# Equivalent to proc_namespace.c:show_vfsmnt
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# However, that has the ability to call into s_op functions
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# whereas we cannot and must make do with the information we can obtain.
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def invoke(self, arg, from_tty):
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argv = gdb.string_to_argv(arg)
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if len(argv) >= 1:
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try:
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pid = int(argv[0])
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except:
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raise gdb.GdbError("Provide a PID as integer value")
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else:
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pid = 1
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task = tasks.get_task_by_pid(pid)
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if not task:
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raise gdb.GdbError("Couldn't find a process with PID {}"
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.format(pid))
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namespace = task['nsproxy']['mnt_ns']
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if not namespace:
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raise gdb.GdbError("No namespace for current process")
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for vfs in lists.list_for_each_entry(namespace['list'],
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mount_ptr_type, "mnt_list"):
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devname = vfs['mnt_devname'].string()
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devname = devname if devname else "none"
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pathname = ""
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parent = vfs
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while True:
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mntpoint = parent['mnt_mountpoint']
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pathname = utils.dentry_name(mntpoint) + pathname
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if (parent == parent['mnt_parent']):
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break
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parent = parent['mnt_parent']
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if (pathname == ""):
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pathname = "/"
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superblock = vfs['mnt']['mnt_sb']
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fstype = superblock['s_type']['name'].string()
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s_flags = int(superblock['s_flags'])
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m_flags = int(vfs['mnt']['mnt_flags'])
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rd = "ro" if (s_flags & constants.LX_MS_RDONLY) else "rw"
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gdb.write(
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"{} {} {} {}{}{} 0 0\n"
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.format(devname,
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pathname,
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fstype,
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rd,
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info_opts(FS_INFO, s_flags),
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info_opts(MNT_INFO, m_flags)))
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LxMounts()
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class LxFdtDump(gdb.Command):
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"""Output Flattened Device Tree header and dump FDT blob to the filename
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specified as the command argument. Equivalent to
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'cat /proc/fdt > fdtdump.dtb' on a running target"""
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def __init__(self):
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super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA,
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gdb.COMPLETE_FILENAME)
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def fdthdr_to_cpu(self, fdt_header):
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fdt_header_be = ">IIIIIII"
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fdt_header_le = "<IIIIIII"
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if utils.get_target_endianness() == 1:
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output_fmt = fdt_header_le
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else:
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output_fmt = fdt_header_be
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return unpack(output_fmt, pack(fdt_header_be,
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fdt_header['magic'],
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fdt_header['totalsize'],
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fdt_header['off_dt_struct'],
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fdt_header['off_dt_strings'],
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fdt_header['off_mem_rsvmap'],
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fdt_header['version'],
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fdt_header['last_comp_version']))
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def invoke(self, arg, from_tty):
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if not constants.LX_CONFIG_OF:
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raise gdb.GdbError("Kernel not compiled with CONFIG_OF\n")
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if len(arg) == 0:
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filename = "fdtdump.dtb"
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else:
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filename = arg
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py_fdt_header_ptr = gdb.parse_and_eval(
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"(const struct fdt_header *) initial_boot_params")
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py_fdt_header = py_fdt_header_ptr.dereference()
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fdt_header = self.fdthdr_to_cpu(py_fdt_header)
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if fdt_header[0] != constants.LX_OF_DT_HEADER:
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raise gdb.GdbError("No flattened device tree magic found\n")
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gdb.write("fdt_magic: 0x{:02X}\n".format(fdt_header[0]))
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gdb.write("fdt_totalsize: 0x{:02X}\n".format(fdt_header[1]))
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gdb.write("off_dt_struct: 0x{:02X}\n".format(fdt_header[2]))
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gdb.write("off_dt_strings: 0x{:02X}\n".format(fdt_header[3]))
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gdb.write("off_mem_rsvmap: 0x{:02X}\n".format(fdt_header[4]))
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gdb.write("version: {}\n".format(fdt_header[5]))
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gdb.write("last_comp_version: {}\n".format(fdt_header[6]))
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inf = gdb.inferiors()[0]
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fdt_buf = utils.read_memoryview(inf, py_fdt_header_ptr,
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fdt_header[1]).tobytes()
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try:
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f = open(filename, 'wb')
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except:
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raise gdb.GdbError("Could not open file to dump fdt")
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f.write(fdt_buf)
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f.close()
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gdb.write("Dumped fdt blob to " + filename + "\n")
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LxFdtDump()
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