(ack, forgot to reply to list)
On 06/08/2012 12:26 AM, Richard Weinberger wrote:
> Am 07.06.2012 22:59, schrieb Martin Pärtel:
>> Signal handlers in UML guest processes now get correct siginfo_t fields
>> for SIGTRAP, SIGFPE, SIGILL and SIGBUS. Specifically, si_addr and si_code
>> are now correct where previously they were si_addr = NULL and si_code = 128.
>
> What exactly is broken?
> In my SIGSEGV test case si_addr is not NULL, it contains the correct faulting
> address.
>
SIGSEGV is probably fine. At least SIGFPE is not. Test program below.
>> +
>> + ptrace(PTRACE_GETSIGINFO, pid, 0,&si);
>> +
>
> Doesn't this leak the host siginfo_t into the guest?
>
Docs for PTRACE_GETSIGINFO say `si' gets a copy. After that, `si' is not
used for anything other than giving it to the guest. But I really can't
say I understand the surrounding code too well so please review carefully :)
---
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
void handler(int num, siginfo_t *info, void *data)
{
printf("CAUGHT SIGNAL %d - si_addr = %p - si_code = %d\n", num,
info->si_addr, info->si_code);
_exit(1);
}
int main()
{
struct sigaction act;
act.sa_sigaction = &handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
sigaction(SIGFPE, &act, NULL);
printf("%d\n", 3 / 0);
return 0;
}
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