[sbachman@saveware.com] libc/1534: When a program execl()'s in a signal function, the new program no longer responds to any signals set by the user.

[Andreas Jaeger]

Hi glibc developers & testers,

We've received the appended bug report.  For me this looks like a bug
in the kernel.  AFAIK Posix explicitly mentions execl as a function
which is allowed to be called from a signal handler (printf is not
signal safe but I don't think that this is the problem here).

What do you think?  Should this be forwarded to linux-kernel?

Andreas


P.S. Here's the test program - name the executable `testd' and send it
kill -INT and kill -HUP.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/*  2000 (c) Scott Bachmann sbachman@saveware.com */
/*  Help from: ds111@cornell.edu */

#include <signal.h>
#include <stdio.h>
#include <unistd.h>

void foo2( int sig )
{  printf("Foo 2 you too at %d\n",sig);  }

void foo( int sig )
{
   printf("I got signal %d\n", sig);
   execl("./testd","./testd",(char *) 0);
}

int main()
{
   struct sigaction newaction;
 
   newaction.sa_handler = foo;
   newaction.sa_flags = 0;

   if ( sigaction( SIGINT, &newaction, NULL ) == -1)
     perror("Could not install the new signal handler");

   newaction.sa_handler = foo2;
   if ( sigaction( SIGHUP, &newaction, NULL ) == -1)
     perror("Could not install the new signal handler");

   printf("Signals set, program loaded, entering while\n");
   while (1)  {
     printf("Hello Ball!! \n");
     sleep(2);
   }
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~