[Linux-abi-devel] sigsuspend

[Alexander S. <as...@es...>]

Hi!

(sorry for imperfect English)

I am running MSM-UNIX 4.3.0 for SCO under iBCS2. It is work fine mainly.
However I have investigate that sigsuspend implementation in iBCS is _incorrect_.
Although sigsuspend returns EINTR when signal arrives, signal handlers are not invoked.
Probably similar problem affects sigpause emulation too.

As far as I can see linux-abi contains almost the same abi_sigsuspend code
(http://www.kernel.org/pub/linux/kernel/people/hch/linux-abi/v2.4/linux-abi-2.4.18.0.patch.gz)
So I believe my idea & code below will be useful for linux-abi developers.

What do you think ?

------------------------------------------------------------------------------
[signal.c]
#ifndef __sparc__
int abi_sigsuspend(struct pt_regs * regs)
{
        unsigned long * set;
        unsigned long oldset;
        old_sigset_t newset;
        int error;

#if defined(EMU_BSD) && defined(PER_BSD)
        if (personality(PER_BSD)) {
                oldset = get_syscall_parameter (regs, 0);
        } else
#endif
        {
                set = (unsigned long *)get_syscall_parameter (regs, 0);
                error = get_user(oldset, set);
                if (error)
                        return error;
        }
        newset = map_bitvec(oldset,
                current->exec_domain->signal_map);

#ifdef IBCS_TRACE
        if ((ibcs_trace & TRACE_SIGNAL) || ibcs_func_p->trace)
                printk("iBCS: sigsuspend oldset, newset = %lx %lx\n",
                        oldset, newset);
#endif
        {
#if 0
            extern do_sigpause(unsigned int, struct pt_regs *);
            return do_sigpause(newset, regs);
#endif
        }

        // modby assur
        {
            volatile struct pt_regs *sregs;
#define alloca(size) __builtin_alloca(size)
            // allocate sregs on our stack
            sregs = (struct pt_regs*)alloca(sizeof(struct pt_regs));
            *sregs = *regs; // initialize it
            sregs->ebx = 0; // modify according linux-syscall conventions
            sregs->ecx = oldset;
            sregs->edx = newset; // (mask)
            error = SYS(sigsuspend)();
            if (regs->esp != sregs->esp) // frame created on user stack
            {
                char *sigframe = (char*)(sregs->esp); // see setup_frame()
                // sorry, offset_of(struct sigframe, sc) hardcoded as 8
                struct sigcontext *sc = (struct sigcontext*)(sigframe + 8);
                sc->ebx = regs->ebx; // restore altered registers
                sc->ecx = regs->ecx;
                sc->edx = regs->edx;
                *regs = *sregs; // invoke signal-handler
            }
        }
        return error;
}
#endif /* __sparc__ */
------------------------------------------------------------------------------

WBR Alexander