#include <signal.h>
#include <unistd.h>
+#include "sig-handler.h"
#include "xalloc.h"
#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
-
/* ========================================================================= */
static bool fatal_signals_initialized = false;
if (!fatal_signals_initialized)
{
-#if HAVE_SIGACTION
size_t i;
for (i = 0; i < num_fatal_signals; i++)
struct sigaction action;
if (sigaction (fatal_signals[i], NULL, &action) >= 0
- /* POSIX says that SIG_IGN can only occur when action.sa_flags
- does not contain SA_SIGINFO. But in Linux 2.4, for example,
- SA_SIGINFO can actually be set and is ignored when sa_handler
- is SIG_IGN. So don't bother testing for SA_SIGINFO. */
- && action.sa_handler == SIG_IGN)
+ && get_handler (&action) == SIG_IGN)
fatal_signals[i] = -1;
}
-#endif
fatal_signals_initialized = true;
}
uninstall_handlers ()
{
size_t i;
+ struct sigaction action;
+ action.sa_handler = SIG_DFL;
+ action.sa_flags = 0;
+ sigemptyset (&action.sa_mask);
for (i = 0; i < num_fatal_signals; i++)
if (fatal_signals[i] >= 0)
- signal (fatal_signals[i], SIG_DFL);
+ sigaction (fatal_signals[i], &action, NULL);
}
}
/* Now execute the signal's default action.
- If signal() blocks the signal being delivered for the duration of the
- signal handler's execution, the re-raised signal is delivered when this
- handler returns; otherwise it is delivered already during raise(). */
+ If the signal being delivered was blocked, the re-raised signal would be
+ delivered when this handler returns. But the way we install this handler,
+ no signal is blocked, and the re-raised signal is delivered already
+ during raise(). */
uninstall_handlers ();
raise (sig);
}
install_handlers ()
{
size_t i;
-
+ struct sigaction action;
+
+ action.sa_handler = &fatal_signal_handler;
+ /* If we get a fatal signal while executing fatal_signal_handler, enter
+ fatal_signal_handler recursively, since it is reentrant. Hence no
+ SA_RESETHAND. */
+ action.sa_flags = SA_NODEFER;
+ sigemptyset (&action.sa_mask);
for (i = 0; i < num_fatal_signals; i++)
if (fatal_signals[i] >= 0)
- signal (fatal_signals[i], &fatal_signal_handler);
+ sigaction (fatal_signals[i], &action, NULL);
}