python脚本在工作中的应用-复杂替换

背景：与某企业的合作项目，codereview中出现的不安全函数strcpy和sprintf整改问题。

整改方案如下：

//Noncompliant Code Example
sprintf(str, "%s", message);   // Noncompliant
strcpy(str, message); // Noncompliant
//Compliant Solution
snprintf(str, sizeof(str), "%s", message);
strlcpy(str, message, sizeof(str));

strncpy(str, message, sizeof(str) -1); // Leave room for null
str[sizeof(str) - 1] = '\0'; // Make sure the string is null-terminated

在4个c文件中，一共有1千多处需要整改，工作量巨大，故写了个python脚本帮助替换，立刻就搞定了

import os
import shutil
import sys
def repalce_string(filepath):
    print("----------------------开始替换文字----------------------")
    tmppath = filepath+'.tmp'
    tmpfile = open(tmppath,'w')
    with open(filepath,'r') as f:
        lines = f.readlines()
        for line in lines:
            if 'strcpy' in line:
                index = line.find('(')
                index2 = line.find(',')
                index3 = line.find(');')
                str1 = line[index+1:index2]
                str2 = line[index2+1:index3]
                repl = '''
                strncpy({},{},sizeof({})-1);
                {}[sizeof({})-1]='\0';
                '''.format(str1,str2,str1,str1,str1)
                tmpfile.write(repl)
            else:
                tmpfile.write(line)
    tmpfile.close()
    tmpfile = None
    try:
        shutil.copyfile(tmppath, filepath)
    except Exception as e:
        print("!!!!!!!!!!! 替换文字失败 !!!!!!!!!! ", e)
        sys.exit()
    finally:
        os.remove(tmppath)

if __name__ == '__main__':
    filepath = sys.argv[1]
    repalce_string(filepath)