kernel/system/do_getksig.c

   1 /* The kernel call that is implemented in this file:
   2  *   m_type:    SYS_GETKSIG
   3  *
   4  * The parameters for this kernel call are:
   5  *     m2_i1:   SIG_ENDPT       # process with pending signals
   6  *     m2_l1:   SIG_MAP         # bit map with pending signals
   7  */
   8
   9 #include "../system.h"
  10 #include <signal.h>
  11 #include <minix/endpoint.h>
  12
  13 #if USE_GETKSIG
  14
  15 /*===========================================================================*
  16  *                            do_getksig                                     *
  17  *===========================================================================*/
  18 PUBLIC int do_getksig(struct proc * caller, message * m_ptr)
  19 {
  20 /* PM is ready to accept signals and repeatedly does a kernel call to get
  21  * one. Find a process with pending signals. If no signals are available,
  22  * return NONE in the process number field.
  23  * It is not sufficient to ready the process when PM is informed, because
  24  * PM can block waiting for FS to do a core dump.
  25  */
  26   register struct proc *rp;
  27
  28   /* Find the next process with pending signals. */
  29   for (rp = BEG_USER_ADDR; rp < END_PROC_ADDR; rp++) {
  30       if (RTS_ISSET(rp, RTS_SIGNALED)) {
  31           /* store signaled process' endpoint */
  32           m_ptr->SIG_ENDPT = rp->p_endpoint;
  33           m_ptr->SIG_MAP = rp->p_pending;       /* pending signals map */
  34           sigemptyset(&rp->p_pending);          /* ball is in PM's court */
  35           RTS_UNSET(rp, RTS_SIGNALED);          /* blocked by SIG_PENDING */
  36           return(OK);
  37       }
  38   }
  39
  40   /* No process with pending signals was found. */
  41   m_ptr->SIG_ENDPT = NONE;
  42   return(OK);
  43 }
  44 #endif /* USE_GETKSIG */
  45