Subject: Re: linux emulation questions
To: None <Robert.Baron@ERNST.MACH.CS.CMU.EDU>
From: Brad Spencer <>
List: port-i386
Date: 09/26/1996 20:31:34
   I am running some emulated linux code, in a 1.2'ish kernel from
   August 5.

   1. Is there still no way to distinguish between svr4 elf and linux elf.
      If so, I'd like to suggest that the kernel issue a warning iff
      the kernel has both compat_svr4 and compat_linux on.


I don't exactly have an answer to this, but if you are having problems
running both types of binaries.....

I found that if one reverses the order in which the binary is probed,
things seem to work much better.  In particular, in exec_elf.c make
the elf_probe_funcs stucture look like the following:

int (*elf_probe_funcs[]) __P((struct proc *, struct exec_package *,
                              char *, u_long *)) = {
#ifdef COMPAT_SVR4

Perhaps this emulation function could use used in a more effective

 * Set the 'personality' (emulation mode) for the current process. Only
 * accept the Linux personality here (0). This call is needed because
 * the Linux ELF crt0 issues it in an ugly kludge to make sure that
 * ELF binaries run in Linux mode, not SVR4 mode.
linux_sys_personality(p, v, retval)
        struct proc *p;
        void *v;
        register_t *retval;
        struct linux_sys_personality_args /* {
                syscallarg(int) per;
        } */ *uap = v;

        if (SCARG(uap, per) != 0)
                return EINVAL;
        retval[0] = 0;
        return 0;

Brad Spencer -