gistfile1.txt

let qemuBinfmtWrapperSource = pkgs.writeTextDir "qemu-binfmt-wrapper.c"
      ''
        #include <unistd.h>
        #include <string.h>
        #include <stdio.h>
        #include <sys/auxv.h>

        int main(int argc,char ** argv) {
          int fd = (int) getauxval(AT_EXECFD);
          size_t sz = snprintf(NULL, 0, "/proc/self/fd/%d", fd) + 1;
          char fn[sz];
          snprintf(fn, sz, "/proc/self/fd/%d", fd);

          char * realArgv[argc + 2];
          realArgv[0] = "qemu-riscv64";
          realArgv[1] = "-0";
          realArgv[2] = argv[2];
          realArgv[3] = fn;
          memcpy(realArgv + 4, argv + 3, (argc - 3) * sizeof argv[0]);
          realArgv[argc + 1] = NULL;

          execv("${pkgs.qemu-riscv}/bin/qemu-riscv64", realArgv);
          perror("Running qemu-riscv64");
          return -1;
        }
      '';
    qemuBinfmtWrapper = pkgs.runCommandCC "qemu-binfmt-wrapper" {}
      ''
        mkdir -p $out/bin
        cc ${qemuBinfmtWrapperSource}/qemu-binfmt-wrapper.c -O3 -o $out/bin/qemu-binfmt-wrapper
        fixupPhase
      '';
in { boot.binfmtMiscRegistrations.riscv64 =
        { magicOrExtension = ''\x7f\x45\x4c\x46\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xf3\x00'';
          mask = ''\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff'';
          interpreter = "${qemuBinfmtWrapper}/bin/qemu-binfmt-wrapper";
          preserveArgvZero = true;
          matchCredentials = true;
        };
   }