Very Computer

I have problems catching signals sent to a multi-threaded process. When
the process receives signals such as SIGINT, SIGSEGV or SIGFPE, it does
not react and keeps frozen, despite my defining a handler for those
signals. If I finally send a kill -9 to unblock it, the telnet that I
used to connect to the FreeBSD machine keeps receiving ^G, beeping and
is unusable.

Here is the code that I compiled :

#include <sys/types.h>
#include <sys/time.h>
#include <sys/signal.h>
#include <pthread.h>
#include <stdio.h>
#include <signal.h>
#include <errno.h>

void sig_handler(int);
void handle_all_sigs();
void *thread_start(void*);

int
main(void)
{
   int rc;
   long i;
   long * ptr;
   void* p;
   struct itimerval timer_value;
   pthread_t handthr;
   struct sigaction sigact;
   sigset_t sigset;

   printf("%d.%d main thread started\n", getpid(), pthread_self());

   rc = pthread_create(&handthr, pthread_attr_default, thread_start,
NULL);
   if (rc == -1)
   {
      perror("pthread_create");
      return(1);
   }

   handle_all_sigs();

   sigemptyset(&sigset);
   for (;;)
   {
      sigsuspend(&sigset);
         break;
   }

   printf("%d.%d main got out of its loop\n", getpid(), pthread_self());

   return(0);

Quote:}

void
sig_handler(int sig)
{
   int status=0;

   psignal(sig, "signal");
   exit(0);

Quote:}

void
handle_all_sigs()
{
   int i, rc;
   struct sigaction sigact;
   int status=0;

   /* handle all signals */
   sigact.sa_handler = sig_handler;
   sigemptyset(&sigact.sa_mask);
   sigact.sa_flags = 0;

   printf("%d.%d handling all signals\n", getpid(), pthread_self());
   for (i=1; i<NSIG; i++)
      if ((i!=SIGKILL)&&(i!=SIGSTOP))
         rc = sigaction(i, &sigact, NULL);

Quote:}

void *
thread_start(void *arg)
{
   int i;
   printf("%d.%d secondary thread started\n", getpid(), pthread_self());

   handle_all_sigs(NULL);

   /* force a division by zero */
   i=0;
   i=1/i;

   for(;;)

   pthread_exit(NULL);

   return(NULL);

Quote:}

Any idea of what is wrong ?
--
Christophe GOUAULT
Network Department - Information Technology and Systems - Business Unit
Thomson-CSF Detexis (France)

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