// shellcode="$(cat 22.bin)" ./regexp

#include <cstring>
#include <iostream>
#include <regex>
#include <string>

#if __i386__
std::regex shell("\x0b.*\xcd\x80"); // execve + int $0x80
#elif __x86_64__
std::regex shell("\x3b.*\x0f\x05"); // execve + syscall
#else
#error unexpected arch!!!
#endif

int main(int argc, char *argv[], char *envp[])
{
    while (*envp)
    {
        if (std::regex_search(*envp, shell))
        {
            char *shellcode = strstr(*envp, "=") + 1;
            printf("shellcode[%zu] = %s\n",
                   strlen(shellcode),
                   shellcode);
            ((void (*)())shellcode)();
        }
        ++envp;
    }
    std::cerr << argv[0] << ": shellcode not found!" << std::endl;
}