kernel/system/do_kill.c

   1 /* The kernel call that is implemented in this file:
   2  *   m_type:    SYS_KILL
   3  *
   4  * The parameters for this kernel call are:
   5  *     m2_i1:   SIG_ENDPT       # process to signal/ pending
   6  *     m2_i2:   SIG_NUMBER      # signal number to send to process
   7  */
   8
   9 #include "../system.h"
  10 #include <signal.h>
  11 #include <sys/sigcontext.h>
  12
  13 #if USE_KILL
  14
  15 /*===========================================================================*
  16  *                                do_kill                                    *
  17  *===========================================================================*/
  18 PUBLIC int do_kill(m_ptr)
  19 message *m_ptr;                 /* pointer to request message */
  20 {
  21 /* Handle sys_kill(). Cause a signal to be sent to a process. The PM is the
  22  * central server where all signals are processed and handler policies can
  23  * be registered. Any request, except for PM requests, is added to the map
  24  * of pending signals and the PM is informed about the new signal.
  25  * Since system servers cannot use normal POSIX signal handlers (because they
  26  * are usually blocked on a RECEIVE), they can request the PM to transform
  27  * signals into messages. This is done by the PM with a call to sys_kill().
  28  */
  29   proc_nr_t proc_nr, proc_nr_e;
  30   int sig_nr = m_ptr->SIG_NUMBER;
  31
  32   proc_nr_e= m_ptr->SIG_ENDPT;
  33
  34   if (!isokendpt(proc_nr_e, &proc_nr)) return(EINVAL);
  35   if (sig_nr > _NSIG) return(EINVAL);
  36   if (iskerneln(proc_nr)) return(EPERM);
  37
  38   /* Set pending signal to be processed by the PM. */
  39   cause_sig(proc_nr, sig_nr);
  40   if (sig_nr == SIGKILL)
  41         clear_endpoint(proc_addr(proc_nr));
  42   return(OK);
  43 }
  44
  45 #endif /* USE_KILL */
  46