How to compile C code and run the compile code with Pexpect?-CodePudding

I have C code and I want to compile and then run it with pexpect. How can I do it?? but this command is not working.

child = pexpect.spawn("gcc -o pwn code.c)

CodePudding user response：

By using this way you can see your output

In [1]: import pexpect    
In [12]: pexpect.spawn("gcc ab.c")                                                                                                                    
Out[12]: <pexpect.pty_spawn.spawn at 0x7efcf4787130>
In [13]: pexpect.spawn("./a.out")                                                                                                                     
Out[13]: <pexpect.pty_spawn.spawn at 0x7efcf432d8e0>

In [14]: pexpect.spawn("./a.out").read()                                           
Out[14]: b'Hello world'

CodePudding user response：

You can add a child.expect_exact(["$", pexpect.EOF, ]) after the pexpect.spawn. That will move the cursor forward and execute the command.

NOTE - Tested on Ubuntu 20.04 using Python 3.8

import sys

import pexpect

print("Method 1:")
child = pexpect.spawn("gcc -o pwn code.c")
child.logfile_read = sys.stdout.buffer
child.expect_exact(["$", pexpect.EOF, ])
child = pexpect.spawn("./pwn")
child.logfile_read = sys.stdout.buffer
child.expect_exact(["$", pexpect.EOF, ])

Output:

Method 1:
Hello, world!

Instead of spawning two children, though, you may want to try these alternatives:

import sys

import pexpect

print("Method 2:")
child = pexpect.spawn("bash")
child.logfile_read = sys.stdout.buffer
child.expect_exact("$")
child.sendline("gcc -o pwn2 code.c")
child.expect_exact("$")
child.sendline("./pwn2")
child.expect_exact("$")
child.close()

print("Method 3:")
list_of_commands = ["gcc -o pwn3 code.c", "./pwn3", ]
for c in list_of_commands:
    command_output, exitstatus = pexpect.run(c, withexitstatus=True)
    if exitstatus != 0:
        print("Houston, we've had a problem.")
    print(command_output.decode().strip())

Output:

Method 2:
$ gcc -o pwn2 code.c
$ ./pwn2
Hello, world!
$
Method 3:

Hello, world!

Process finished with exit code 0