[impl]

If anyone's looking for an example, I used this trick a few months ago to embed a tiny helper binary[0] directly into my application[1] so I wouldn't have to ship two executables or add "hidden" behavior to the main program. It works really well (on Linux)!

[0]: https://github.com/impl/systemd-user-sleep/blob/666cf29871b1...

[1]: https://github.com/impl/systemd-user-sleep/blob/666cf29871b1...

[jart]

Here's a simple concrete example for folks who don't know Rust:

    int main(int argc, char *argv[]) {
    #define TINY_ELF_PROGRAM "\
    \177\105\114\106\002\001\001\000\000\000\000\000\000\000\000\000\
    \002\000\076\000\001\000\000\000\170\000\100\000\000\000\000\000\
    \100\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\
    \000\000\000\000\100\000\070\000\001\000\000\000\000\000\000\000\
    \001\000\000\000\005\000\000\000\000\000\000\000\000\000\000\000\
    \000\000\100\000\000\000\000\000\000\000\100\000\000\000\000\000\
    \200\000\000\000\000\000\000\000\200\000\000\000\000\000\000\000\
    \000\020\000\000\000\000\000\000\152\052\137\152\074\130\017\005"
      int fd = memfd_create("foo", MFD_CLOEXEC);
      write(fd, TINY_ELF_PROGRAM, sizeof(TINY_ELF_PROGRAM)-1);
      fexecve(fd, argv, environ);
    }

Who here is brave enough to run my C string?

[anshargal]

I had to add

  #define _GNU_SOURCE
  #include <sys/mman.h>
  #include <unistd.h>

I've tested in Fabrice Bellard JSLinux with tcc (x86 arch) and on https://replit.com/languages/c (x64). I failed to see any side effect at all. gdb "catch syscall" doesn't show anything interesting too. Looks like TINY_ELF_PROGRAM is not doing anything.

[tralarpa]

It returns the answer to an important question :)

Edit: Wouldn't mov be shorter than push/pop? (I am not very familar with x86)