Re: [Qemu-devel] ARM syscall 186.

[Fabrice Bellard]

Hi,

Your patch is not correct because it should change the emulated stack, 
not the host stack. You must make modifications in signal.c to have it 
working and you should never call the host sigaltstack() syscall.

Fabrice.

James Pellow wrote:
> Hi All,
>
> In the quest for a running gentoo, I found the need for ARM syscall 186.  This 
> is required to get ncurses to install.  This seems to work for me, though I 
> have only tested it in the context of an ncurses install.  Let me know if 
> something isn't right and I will fix it.  I spent a bit more time looking at 
> the proper way to handle things this time, so I am pretty sure this is 
> actually correct :)  Thanks for any feedback.  Here is the patch:
>
> ------------------------------------------------------------------------------------------------------------
>
> diff -ruN qemu-0.6.1/linux-user/syscall.c qemu-0.6.1_new/linux-user/syscall.c
> --- qemu-0.6.1/linux-user/syscall.c     2004-11-14 12:51:33.000000000 -0800
> +++ qemu-0.6.1_new/linux-user/syscall.c 2004-12-06 00:05:26.139467848 -0800
> @@ -2700,7 +2700,23 @@
>      case TARGET_NR_capset:
>          goto unimplemented;
>      case TARGET_NR_sigaltstack:
> -        goto unimplemented;
> +        {
> +           struct target_stack_t *ss_target  = (void *)arg1;
> +           struct target_stack_t *oss_target = (void *)arg2;
> +           stack_t ss, oss;
> +
> +           ss.ss_sp    = (void *)tswapl(ss_target->ss_sp);
> +           ss.ss_flags = tswap32(ss_target->ss_flags);
> +           ss.ss_size  = tswapl(ss_target->ss_size);
> +
> +           ret = get_errno(sigaltstack(&ss, &oss));
> +           if (!is_error(ret) && oss_target != NULL) {
> +               oss_target->ss_sp    = tswapl((long)oss.ss_sp);
> +               oss_target->ss_flags = tswap32(oss.ss_flags);
> +               oss_target->ss_size  = tswapl(oss.ss_size);
> +           }
> +        }
> +        break;
>      case TARGET_NR_sendfile:
>          goto unimplemented;
>  #ifdef TARGET_NR_getpmsg
> diff -ruN qemu-0.6.1/linux-user/syscall_defs.h 
> qemu-0.6.1_new/linux-user/syscall_defs.h
> --- qemu-0.6.1/linux-user/syscall_defs.h        2004-11-14 12:51:33.000000000 
> -0800
> +++ qemu-0.6.1_new/linux-user/syscall_defs.h    2004-12-05 22:40:00.249721536 
> -0800
> @@ -97,6 +97,12 @@
>  #define TARGET_IOWU(type,nr)   TARGET_IOC(TARGET_IOC_WRITE,(type),
> (nr),TARGET_IOC_SIZEMASK)
>  #define TARGET_IOWRU(type,nr)  TARGET_IOC(TARGET_IOC_READ|TARGET_IOC_WRITE,
> (type),(nr),TARGET_IOC_SIZEMASK)
>
> +struct target_stack_t {
> +    target_long ss_sp;
> +    int         ss_flags;
> +    target_long ss_size;
> +};
> +
>  struct target_sockaddr {
>      uint16_t sa_family;
>      uint8_t sa_data[14];
>
> ---------------------------------------------------------------------------------------------------------------
>
> Cheers,