ctypes return a string from c function

I'm a Python veteran, but haven't dabbled much in C. After half a day of not finding anything on the internet that works for me, I thought I would ask here and get the help I need.

What I want to do is write a simple C function that accepts a string and returns a different string. I plan to bind this function in several languages (Java, Obj-C, Python, etc.) so I think it has to be pure C?

Here's what I have so far. Notice I get a segfault when trying to retrieve the value in Python.

hello.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

const char* hello(char* name) {
    static char greeting[100] = "Hello, ";
    strcat(greeting, name);
    strcat(greeting, "!\n");
    printf("%s\n", greeting);
    return greeting;
}

main.py

import ctypes
hello = ctypes.cdll.LoadLibrary('./hello.so')
name = "Frank"
c_name = ctypes.c_char_p(name)
foo = hello.hello(c_name)
print c_name.value # this comes back fine
print ctypes.c_char_p(foo).value # segfault

I've read that the segfault is caused by C releasing the memory that was initially allocated for the returned string. Maybe I'm just barking up the wrong tree?

What's the proper way to accomplish what I want?

In hello.c you return a local array. You have to return a pointer to an array, which has to be dynamically allocated using malloc.

char* hello(char* name)
{ 
    char hello[] = "Hello ";
    char excla[] = "!\n";
    char *greeting = malloc ( sizeof(char) * ( strlen(name) + strlen(hello) + strlen(excla) + 1 ) );
    if( greeting == NULL) exit(1);
    strcpy( greeting , hello);
    strcat(greeting, name);
    strcat(greeting, excla);
    return greeting;
}