#! /usr/bin/python

import sys

#将 形如 fffffff8989 的字符串转换为数字形式。
def to_no(hexstr):
    ret = 0
    start = -1
    len_hexstr = len(hexstr)
    while start>=-len_hexstr:
        c = hexstr[start]
        if c in "0123456789":
            n = ord(c) - ord('0')
        elif c in "abcdef":
            n = ord(c) - ord('a') + 0xa
        elif c in "ABCDEF":
            n = ord(c) - ord('A') + 0xa
        ret |= long(n<<((-start-1)*4))
        start -= 1
    return ret

# 计算addr-base
def sym_offset(addr, base):
    if base == "missing-base":
        return "missing-offset"
    addr = to_no(addr)
    base = to_no(base)
    return hex(int(addr-base))

lines = file("System.map").readlines()
result=""

# 求.text的开始地址
base="missing-base"
for line in lines:
    line = line.strip()
    addr, type, sym = line.split(" ")
    if type in "tT":
        if sym in ("startup_64", "startup_32"):
            base = addr
            break
# 生成lds中的符号行。
for line in lines:
    line = line.strip()
    addr, type, sym = line.split(" ")
    if type in "tT":
        offset = sym_offset(addr, base)
        result+="\t%s = %s; /* orig: 0x%s */\n" % (sym, offset, addr)

# 生成需要的脚本
template="""
OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
SECTIONS
{
  . = 0x%s;
    .text . : {
        *(.data)
%s}
}
"""
print template % (base, result)


ffffffff80466ca0 <interruptible_sleep_on>:
ffffffff80466ca0: 55 push %rbp
ffffffff80466ca1: 48 ba ff ff ff ff ff mov $0x7fffffffffffffff,%rdx
ffffffff80466ca8: ff ff 7f
ffffffff80466cab: be 01 00 00 00 mov $0x1,%esi
ffffffff80466cb0: 48 89 e5 mov %rsp,%rbp
ffffffff80466cb3: c9 leaveq
ffffffff80466cb4: e9 c7 fe ff ff jmpq ffffffff80466b80 <__sched_text_start>
ffffffff80466cb9: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)

ffffffff80466cc0 <schedule>:
ffffffff80466cc0: 55 push %rbp
ffffffff80466cc1: 48 c7 c0 80 ef 62 80 mov $0xffffffff8062ef80,%rax
ffffffff80466cc8: 48 c7 c2 00 b4 62 80 mov $0xffffffff8062b400,%rdx
ffffffff80466ccf: 48 89 e5 mov %rsp,%rbp
ffffffff80466cd2: 41 57 push %r15
ffffffff80466cd4: 41 56 push %r14
ffffffff80466cd6: 41 55 push %r13
ffffffff80466cd8: 41 54 push %r12
ffffffff80466cda: 53 push %rbx
ffffffff80466cdb: 48 81 ec 98 00 00 00 sub $0x98,%rsp
ffffffff80466ce2: 48 c7 85 78 ff ff ff movq $0xffffffff8062ef80,-0x88(%rbp)
ffffffff80466ce9: 80 ef 62 80