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glibc  2.9
Functions
catch-signal.c File Reference
#include <hurd/signal.h>
#include <hurd/sigpreempt.h>
#include <string.h>
#include <assert.h>

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Functions

error_t hurd_catch_signal (sigset_t sigset, unsigned long int first, unsigned long int last, error_t(*operate)(struct hurd_signal_preemptor *), sighandler_t handler)
error_t hurd_safe_memset (void *dest, int byte, size_t nbytes)
error_t hurd_safe_copyout (void *dest, const void *src, size_t nbytes)
error_t hurd_safe_copyin (void *dest, const void *src, size_t nbytes)
error_t hurd_safe_memmove (void *dest, const void *src, size_t nbytes)

Function Documentation

error_t hurd_catch_signal ( sigset_t  sigset,
unsigned long int  first,
unsigned long int  last,
error_t(*)(struct hurd_signal_preemptor *)  operate,
sighandler_t  handler 
)

Definition at line 26 of file catch-signal.c.

{
  jmp_buf buf;
  void throw (int signo, long int sigcode, struct sigcontext *scp)
    { longjmp (buf, scp->sc_error ?: EGRATUITOUS); }

  struct hurd_signal_preemptor preemptor =
    {
      sigset, first, last,
      NULL, handler == SIG_ERR ? (sighandler_t) &throw : handler,
    };

  struct hurd_sigstate *const ss = _hurd_self_sigstate ();
  error_t error;

  if (handler == SIG_ERR)
    /* Not our handler; don't bother saving state.  */
    error = 0;
  else
    /* This returns again with nonzero value when we preempt a signal.  */
    error = setjmp (buf);

  if (error == 0)
    {
      /* Install a signal preemptor for the thread.  */
      __spin_lock (&ss->lock);
      preemptor.next = ss->preemptors;
      ss->preemptors = &preemptor;
      __spin_unlock (&ss->lock);

      /* Try the operation that might crash.  */
      (*operate) (&preemptor);
    }

  /* Either FUNCTION completed happily and ERROR is still zero, or it hit
     an expected signal and `throw' made setjmp return the signal error
     code in ERROR.  Now we can remove the preemptor and return.  */

  __spin_lock (&ss->lock);
  assert (ss->preemptors == &preemptor);
  ss->preemptors = preemptor.next;
  __spin_unlock (&ss->lock);

  return error;
}

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error_t hurd_safe_copyin ( void *  dest,
const void *  src,
size_t  nbytes 
)

Definition at line 104 of file catch-signal.c.

{
  error_t operate (struct hurd_signal_preemptor *preemptor)
    {
      memcpy (dest, src, nbytes);
      return 0;
    }
  return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV),
                         (vm_address_t) src, (vm_address_t) src + nbytes,
                         &operate, SIG_ERR);
}

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error_t hurd_safe_copyout ( void *  dest,
const void *  src,
size_t  nbytes 
)

Definition at line 91 of file catch-signal.c.

{
  error_t operate (struct hurd_signal_preemptor *preemptor)
    {
      memcpy (dest, src, nbytes);
      return 0;
    }
  return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV),
                         (vm_address_t) dest, (vm_address_t) dest + nbytes,
                         &operate, SIG_ERR);
}

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error_t hurd_safe_memmove ( void *  dest,
const void *  src,
size_t  nbytes 
)

Definition at line 117 of file catch-signal.c.

{
  jmp_buf buf;
  void throw (int signo, long int sigcode, struct sigcontext *scp)
    { longjmp (buf, scp->sc_error ?: EGRATUITOUS); }

  struct hurd_signal_preemptor src_preemptor =
    {
      sigmask (SIGBUS) | sigmask (SIGSEGV),
      (vm_address_t) src, (vm_address_t) src + nbytes,
      NULL, (sighandler_t) &throw,
    };
  struct hurd_signal_preemptor dest_preemptor =
    {
      sigmask (SIGBUS) | sigmask (SIGSEGV),
      (vm_address_t) dest, (vm_address_t) dest + nbytes,
      NULL, (sighandler_t) &throw,
      &src_preemptor
    };

  struct hurd_sigstate *const ss = _hurd_self_sigstate ();
  error_t error;

  /* This returns again with nonzero value when we preempt a signal.  */
  error = setjmp (buf);

  if (error == 0)
    {
      /* Install a signal preemptor for the thread.  */
      __spin_lock (&ss->lock);
      src_preemptor.next = ss->preemptors;
      ss->preemptors = &dest_preemptor;
      __spin_unlock (&ss->lock);

      /* Do the copy; it might fault.  */
      memmove (dest, src, nbytes);
    }

  /* Either memmove completed happily and ERROR is still zero, or it hit
     an expected signal and `throw' made setjmp return the signal error
     code in ERROR.  Now we can remove the preemptor and return.  */

  __spin_lock (&ss->lock);
  assert (ss->preemptors == &dest_preemptor);
  ss->preemptors = src_preemptor.next;
  __spin_unlock (&ss->lock);

  return error;
}

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error_t hurd_safe_memset ( void *  dest,
int  byte,
size_t  nbytes 
)

Definition at line 77 of file catch-signal.c.

{
  error_t operate (struct hurd_signal_preemptor *preemptor)
    {
      memset (dest, byte, nbytes);
      return 0;
    }
  return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV),
                         (vm_address_t) dest, (vm_address_t) dest + nbytes,
                         &operate, SIG_ERR);
}

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