1#!/usr/bin/env python3
2# SPDX-License-Identifier: GPL-2.0+
3
4"""Decode the evspy_info linker list in a U-Boot ELF image"""
5
6from argparse import ArgumentParser
7import os
8import re
9import struct
10import sys
11
12our_path = os.path.dirname(os.path.realpath(__file__))
13src_path = os.path.dirname(our_path)
14
15sys.path.insert(1, os.path.join(our_path, '../tools'))
16
17from binman import elf
18from u_boot_pylib import tools
19
20# A typical symbol looks like this:
21#   _u_boot_list_2_evspy_info_2_EVT_MISC_INIT_F_3_sandbox_misc_init_f
22PREFIX_FULL = '_u_boot_list_2_evspy_info_2_'
23PREFIX_SIMPLE = '_u_boot_list_2_evspy_info_simple_2_'
24RE_EVTYPE_FULL = re.compile('%s(.*)_3_.*' % PREFIX_FULL)
25RE_EVTYPE_SIMPLE = re.compile('%s(.*)_3_.*' % PREFIX_SIMPLE)
26
27def show_sym(fname, data, endian, evtype, sym):
28    """Show information about an evspy entry
29
30    Args:
31        fname (str): Filename of ELF file
32        data (bytes): Data for this symbol
33        endian (str): Endianness to use ('little', 'big', 'auto')
34        evtype (str): Event type, e.g. 'MISC_INIT_F'
35        sym (elf.Symbol): Symbol to show
36    """
37    def _unpack_val(sym_data, offset):
38        start = offset * func_size
39        val_data = sym_data[start:start + func_size]
40        fmt = '%s%s' % ('>' if endian == 'big' else '<',
41                        'L' if func_size == 4 else 'Q')
42        val = struct.unpack(fmt, val_data)[0]
43        return val
44
45    # Get the data, which is a struct evspy_info
46    sym_data = data[sym.offset:sym.offset + sym.size]
47
48    # Figure out the word size of the struct
49    func_size = 4 if sym.size < 16 else 8
50
51    # Read the function name for evspy_info->func
52    while True:
53        # Switch to big-endian if we see a failure
54        func_addr = _unpack_val(sym_data, 0)
55        func_name = elf.GetSymbolFromAddress(fname, func_addr)
56        if not func_name and endian == 'auto':
57            endian = 'big'
58        else:
59            break
60    has_id = sym.size in [12, 24]
61    if has_id:
62        # Find the address of evspy_info->id in the ELF
63        id_addr = _unpack_val(sym_data, 2)
64
65        # Get the file offset for that address
66        id_ofs = elf.GetFileOffset(fname, id_addr)
67
68        # Read out a nul-terminated string
69        id_data = data[id_ofs:id_ofs + 80]
70        pos = id_data.find(0)
71        if pos:
72            id_data = id_data[:pos]
73        id_str = id_data.decode('utf-8')
74    else:
75        id_str = None
76
77    # Find the file/line for the function
78    cmd = ['addr2line', '-e', fname, '%x' % func_addr]
79    out = tools.run(*cmd).strip()
80
81    # Drop the full path if it is the current directory
82    if out.startswith(src_path):
83        out = out[len(src_path) + 1:]
84    print('%-20s  %-30s  %s' % (evtype, id_str or f'f:{func_name}', out))
85
86def show_event_spy_list(fname, endian):
87    """Show a the event-spy- list from a U-Boot image
88
89    Args:
90        fname (str): Filename of ELF file
91        endian (str): Endianness to use ('little', 'big', 'auto')
92    """
93    syms = elf.GetSymbolFileOffset(fname, [PREFIX_FULL, PREFIX_SIMPLE])
94    data = tools.read_file(fname)
95    print('%-20s  %-30s  %s' % ('Event type', 'Id', 'Source location'))
96    print('%-20s  %-30s  %s' % ('-' * 20, '-' * 30, '-' * 30))
97    for name, sym in syms.items():
98        m_evtype = RE_EVTYPE_FULL.search(name)
99        if not m_evtype:
100            m_evtype = RE_EVTYPE_SIMPLE.search(name)
101        evtype = m_evtype .group(1)
102        show_sym(fname, data, endian, evtype, sym)
103
104def main(argv):
105    """Main program
106
107    Args:
108        argv (list of str): List of program arguments, excluding arvg[0]
109    """
110    epilog = 'Show a list of even spies in a U-Boot EFL file'
111    parser = ArgumentParser(epilog=epilog)
112    parser.add_argument('elf', type=str, help='ELF file to decode')
113    parser.add_argument('-e', '--endian', type=str, default='auto',
114                        help='Big-endian image')
115    args = parser.parse_args(argv)
116    show_event_spy_list(args.elf, args.endian)
117
118if __name__ == "__main__":
119    main(sys.argv[1:])
120