Implement shell escaping, relies on caller to clean up the memory for the escaped string.

os_shell_escape.c

/* Escape a set of characters */
char *os_shell_escape(const char *src) {
    // Maximum Length of the String is 2xthe current length
    char shell_escapes[] = { '\\', '"', '\'', ' ', '\t', ';', '`', '>', '<', '|', '#',
                            '*', '[', ']', '{', '}', '&', '$', '!', ':', '(', ')' };

    char *escaped_string;
    int length = 0;
    int i = 0;

    // Determine how long the string will be
    char *iterator = src;
    for (; *iterator; iterator++) {
        if( strchr(shell_escapes, *iterator) ) {
            length++;
        }
        length++;
    }
    // Allocate the memory
    if( (escaped_string = malloc( length + 1 )) == NULL ) {
        // Return NULL
        return NULL;
    }
    memset(escaped_string, '\0', length + 1);

    // Escape the escapable characters
    iterator=src;
    for( i=0; *iterator; iterator++ ) {
        if ( strchr(shell_escapes, *iterator) ) {
            escaped_string[i] = '\\';
            i++;
        }
        escaped_string[i] = *iterator;
        i++;
    }
    // Return Success
    return escaped_string;
}