siginfo_t structure is not filled in the signal handler

[<harishchandra.rao@wipro.com>]

Hello,

 

       I am working on a Motorola VME 167 card with a 68040 processor. The card is running debian linux 2.2 (kernel 2.2.10). The application I am developing needs to handle signals and needs to know the cause of the signal. For example, if the application executes a divide by zero instruction then it should know in the signal handler if this was the cause.

For this the application checks the value of ‘siginfo_t->si_code’ passed to the signal handler. However, this value seems to always zero.

Following is an example program which does not work:

 

#include <stdio.h>

#include <signal.h>

#include <ucontext.h>

 

void my_signal_handler(int sig, siginfo_t *sigInfo, struct ucontext *scp);

stack_t st;

 

static union

{

char buffer[SIGSTKSZ];

long double ld;

long l;

void *p

} alt_sig_stack;

 

main()

{

  struct sigaction sa;

  int i, j;

  st.ss_flags = 0;

  st.ss_sp = alt_sig_stack.buffer;

  st.ss_size = sizeof(alt_sig_stack.buffer);

  if (sigaltstack(&st, 0) != 0)

    printf("sigaltstack failed\n");

  sa.sa_flags = SA_SIGINFO | SA_ONSTACK;

  sa.sa_sigaction = my_signal_handler;

 

  sigaction(SIGFPE, &sa, NULL);

  j = 10;

  i = 0;

  i = j / i;

}

 

void my_signal_handler(int sig, siginfo_t *sigInfo, struct ucontext *scp)

{

   printf("D0 = %x\n", scp->uc_mcontext.gregs[R_D0]);

   printf("D1 = %x\n", scp->uc_mcontext.gregs[R_D1]);

   printf("D2 = %x\n", scp->uc_mcontext.gregs[R_D2]);

   printf("A0 = %x\n", scp->uc_mcontext.gregs[R_A0]);

   printf("A1 = %x\n", scp->uc_mcontext.gregs[R_A1]);

   printf("A2 = %x\n", scp->uc_mcontext.gregs[R_A2]);

   printf("SP = %x\n", scp->uc_mcontext.gregs[R_SP]);

   printf("PC = %x\n", scp->uc_mcontext.gregs[R_PC]);

   printf("siginfo->si_code = %d\n", sigInfo->si_code);

   printf("siginfo->si_addr = %d\n", sigInfo->si_addr);

   printf("ss_sp = %d\n", scp->uc_stack.ss_sp);

   printf("FPE_INTDIV = %d\n", FPE_INTDIV);

}

 

The above program outputs 0 for si_code where as it should be printing 1 (FPE_INTDIV). Does any body have any solution for this? This seems to be a problem with the kernel. Does any release of the kernel (post 2.2.10) have a fix for this?

 

Regards,

Harish