Python子进程挂起

Question

我正在执行以下子流程...

p.call(["./hex2raw", "<", "exploit4.txt", "|", "./rtarget"])

...它挂了。

但是，如果我执行kmwe236@kmwe236:~/CS485/prog3/target26$ ./hex2raw < exploit4.txt | ./rtarget kmwe236@kmwe236:~/CS485/prog3/target26$ ./hex2raw < exploit4.txt | ./rtarget然后执行正常。 使用输入或管道操作器有什么问题吗？

我也尝试了sp.call(["./hex2raw", "<", "exploit4.txt", "|", "./rtarget"], shell=True)

整个代码看起来像这样UPDATED SUGGESTIONS

import subprocess as sp
import pdb

for i in range(4201265,4201323):
    pdb.set_trace()
    d = hex(i)[2:]
    output = " "
    for i in range(len(d),0,-2):
        output = output + d[i-2:i] + " "

    out_buffer = "00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00" + output + "00 00 00 00"

    text_file = open("exploit4.txt", "w")
    text_file.write("%s" % out_buffer)

 #   sp.call(["./hex2raw", "<", "exploit4.txt", "|", "./rtarget"], shell=True)
    with open("exploit4.txt") as inhandle:
        p = sp.Popen("./hex2raw",stdin=inhandle,stdout=sp.PIPE)
        p2 = sp.Popen("./rtarget",stdin=p.stdout,stdout=sp.PIPE)
        [output,error] = p2.communicate()

我遇到一个错误是

  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
OSError: [Errno 8] Exec format error

调试后，它发生在fire子p = sp.Popen("./hex2raw",stdin=inhandle,stdout=sp.PIPE)调用p = sp.Popen("./hex2raw",stdin=inhandle,stdout=sp.PIPE)

Answer 1

由于您正在使用重定向和管道，因此必须启用shell=True

sp.call(["./hex2raw", "<", "exploit4.txt", "|", "./rtarget"],shell=True)

但它是更清洁的使用Popen两个可执行文件和喂养的内容exploit4.txt作为输入。 下面的示例适合您的情况：

import subprocess

    with open("exploit4.txt") as inhandle:
        p = subprocess.Popen("./hex2raw",stdin=inhandle,stdout=subprocess.PIPE)
        p2 = subprocess.Popen("./rtarget",stdin=p.stdout,stdout=subprocess.PIPE)
        [output,error] = p2.communicate()
        print(output)
        # checking return codes is also a good idea
        rc2 = p2.wait()
        rc = p.wait()

说明：

1. 打开输入文件，得到它的手柄inhandle
2. 打开第一inhandle ，使用inhandle将stdin重定向，并将stdout重定向到输出流。 获取管柄（p）
3. 打开第二个子进程，将stdin与先前的进程stdout重定向，并将stdout重定向到输出流
4. 让第二个进程进行communicate 。 它将通过消耗其输出来“拉”第一个：两个进程都以管道方式工作
5. 获取返回码并打印结果

注意：因为一个或两个可执行文件实际上是Shell或其他非本地可执行文件，所以会出现“格式错误”。 在这种情况下，只需将shell=True选项添加到相关的Popen调用中即可。