servtgt.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/* -----------------------------------------------------------------------
   TgtHandleChildChange - decide what action to take after wait() returns.
		Used in the master only.
   ----------------------------------------------------------------------- */

#ifdef DDEBUG
static char *LastStartNames[] = {
  "NONE", "STEP", "CONT", "RANGE",
  "STEPOFF", "KILLED", "DETACHED"
};

  char *
GetLastStartName (int last_start)
{
  static char buf[32];

  strcpy (buf, LastStartNames[last_start & ~LAST_START]);
  if (last_start & LAST_START) {
    strcat (buf, "+START");
  }
  return buf;
}
#endif

  Boolean
TgtHandleChildChange (PID pid, int *status, int *unexp,
                      CPU_Exception_frame * ctx)
{                               /* return False if continue, else stop */
  int idx, sig;
  int bidx = 0;
  PID_LIST *plst;
  unsigned long PC;
  BASE_BREAK *base = NULL;      /* break_list[0] is really BASE_BREAK */
  int hadStepEmul;
  int origHadStepEmul;
  int stopWanted;

  DPRINTF (("TgtHandleChildChange: pid %d status %x cap\n",
            (int) pid, *status));
  if (unexp)
    *unexp = 0;                 /* initialize to ok */

  /*
   * first, find pid in question 
   */
  idx = FindPidEntry (pid);
  if (idx < 0) {                /* cannot locate this process */
    DPRINTF (("TgtHandleChildChange: unknown process (%s pid)\n",
              FindPidEntry (pid) >= 0 ? "stale" : "unknown"));
    if (unexp)
      *unexp = 1;               /* Unexpected change */
    return (False);             /* unknown: ignore (used to stop and notify) */
  }

  /*
   * found 
   */
  plst = &pid_list[idx];        /* pointer to entry */
  /*
   * first we see if just stopped 
   */

  /*
   * copy ctxt 
   */
  CtxToRegs (ctx, &(plst->regs));

  stopWanted = plst->stop_wanted;
  plst->stop_wanted = 0;        /* For the next time */

  hadStepEmul = BreakClear (plst, -1, -1) > 0;
  origHadStepEmul = hadStepEmul;    /* hadStepEmul is cleared if real bkpt met */

  if (STS_SIGNALLED (*status)) {    /* stopped, not terminated */
    sig = STS_GETSIG (*status); /* signal that stopped us */

    /*
     * now, we read the registers and see what to do next 
     */
    if (TgtPtrace (RPT_GETREGS, pid, (void *) &plst->regs, 0, NULL) < 0) {
      memset (&plst->regs, 0, sizeof (plst->regs));
    }

    /*
     * Get current thread 
     */
    plst->thread = TgtPtrace (RPT_GETTARGETTHREAD, pid, NULL, 0, NULL);

    if (sig == SIGTRAP) {       /* stopped from break/step */
      PC = plst->regs.REG_PC;
      /*
       * Must check PC to see whether in situations where we had
       * step emulation we are on a breakpoint or just
       * have returned from an emulated single-step 
       */
      if (BreakIdentify (plst, 0 /*no adjust */ , -1 /*no thread */ ) > 0) {
        hadStepEmul = 0;
      }
      plst->is_step = hadStepEmul || IS_STEP (plst->regs)
        || plst->last_start == LAST_START;
      DPRINTF (("TgtHandleChildChange: %s last_start %s\n", plst->is_step
                ? "step" : "break", GetLastStartName (plst->last_start)));

      if ((plst->is_step || origHadStepEmul || stopWanted)
          && (plst->last_start == LAST_STEP
              || plst->last_start == LAST_STEPOFF
              || plst->last_start == LAST_RANGE)) {
        DPRINTF (("TgtHandleChildChange: restoring stepped-off bkpt\n"));
        BreakSteppedOff (plst);
      }

      if (plst->last_start == LAST_STEPOFF && (plst->is_step || origHadStepEmul)) { /* stepped off break and now need cont */
        DPRINTF (("TgtHandleChildChange: auto-resuming after step-off\n"));
        plst->last_start = LAST_CONT;   /* convert to normal cont */
        if (!stopWanted) {
          if (TgtPtrace (RPT_CONT, pid, (char *) 1, 0, NULL))
            return True;        /* tell people */
          return (False);       /* wait for change */
        }
        DPRINTF (("TgtHandleChildChange: stop_wanted %d in step-off\n",
                  stopWanted));
        *status = STS_MAKESIG (stopWanted);
        return True;            /* Stop and notify */
      }

      base = plst->break_list ? ((BASE_BREAK *) plst->break_list) :
        ((BASE_BREAK *) NULL);
      /*
       * now see if step in range 
       */

      if (plst->last_start == LAST_RANGE    /* step in range */
          && (plst->is_step || origHadStepEmul) /* not a breakpoint */
          &&PC >= base->range_start && PC <= base->range_end) { /* still in range, keep going */
        if (stopWanted) {
          DPRINTF (("TgtHandleChildChange: stop_wanted %d in step-range\n",
                    stopWanted));
        } else {
          DPRINTF (("TgtHandleChildChange: Reservation at %x\n",
                    plst->regs.REG_PC));
        }
      }
      if (!plst->is_step) {     /* was break */
        bidx = BreakIdentify (plst, 1 /*adjust */ , plst->thread);
        if (bidx == 0) {
          DPRINTF (("TgtHandleChildChange: forwarding bkpt to kernel\n"));
          if (unexp) {
            *unexp = 1;
          }
          return False;
        }
        if (bidx < 0) {         /* Unwanted breakpoint, must step it off */
          ptrace_in pin;
          ptrace_out *out;
          if (origHadStepEmul) {
            DPRINTF (("TgtHandleChildChange: bkpt %x becomes step\n",
                      plst->regs.REG_PC));
            bidx = -bidx;
            plst->is_step = 1;
            base->clr_step = plst->break_list[bidx].type == BRKT_INSTR;
            base->last_break = bidx;
            return True;
          }
          if (stopWanted) {
            DPRINTF (("TgtHandleChildChange: stop_wanted %d at bkpt %x\n",
                      stopWanted, plst->regs.REG_PC));
            /*
             * The PC has already been adjusted by BreakIdentify 
             */
            *status = STS_MAKESIG (stopWanted);
            return True;
          }
          /*
           * All the handling is done in ptrace_2_svc() so call it 
           */
          bidx = -bidx;
          DPRINTF (("TgtHandleChildChange: last %d (%s) restarting bkpt %d\n",
                    plst->last_start, GetLastStartName (plst->last_start),
                    bidx));
          base->clr_step = 1;
          base->last_break = bidx;  /* remember which one */
          plst->running = 0;    /* So that ptrace is accepted */
          pin.pid = plst->pid;

          if (plst->last_start == LAST_STEP) {
            pin.addr.req = RPT_SINGLESTEP;
          } else {
            pin.addr.req = RPT_CONT;
          }
          pin.addr.ptrace_addr_data_in_u.address = 1;
          pin.data = 0;
          pin.flags = PTRFLG_NON_OWNER;
          out = RPCGENSRVNAME (ptrace_2_svc) (&pin, NULL);
          if (out->result == 0)
            return False;       /* Continue waiting */
          DPRINTF (("TgtHandleChildChange: failed to restart bkpt!\n"));
          /*
           * If something went wrong, just stop on breakpoint 
           */
        }
      }
    }

    /*
     * else sig != SIGTRAP 
     */
    /*
     * finally, fill in stop info in break point array base 
     */
    if (bidx > 0) {             /* store break info */
      /*
       * will need to get off the break for SW breakpoints only 
       */
      base->clr_step = plst->break_list[bidx].type == BRKT_INSTR;
      base->last_break = bidx;  /* remember which one */
    } else if (base) {          /* clear break info */
      base->clr_step = False;   /* not stopped on break */
      base->last_break = 0;
    }
    /*
     * decision to notify owner based on last_start 
     */
  } /* stopped */
  else {                        /* terminated */

    if (plst->last_start == LAST_START) {   /* spawn failed */
      TgtNotifyAll (idx, BMSG_EXEC_FAIL, 0, 0, -1, True);
      plst->running = False;    /* not running - dead */
      plst->state = *status;    /* contains errno in high word */
      return (False);
    }

    else if ((UCHAR) (plst->last_start & ~LAST_START) < (UCHAR) LAST_KILLED)
      plst->last_start = LAST_NONE; /* doesn't matter anymore */
    else
      return (False);           /* killed and detach already notified */
  }
  return (True);                /* stop and notify */
}

#ifdef DDEBUG

/*
 * TgtDbgPtrace - debug version of ptrace.
 */

  int
TgtDbgPtrace (int request, PID pid, char *addr, int data, void *addr2)
{
  int diag;

  DPRINTF (("TgtDbgPtrace: entered (%s (%d), %d, %x, %d, %x)\n",
            PtraceName (request), request, pid, (int) addr, data,
            (int) addr2));

  if (request == RPT_WRITETEXT || request == RPT_WRITEDATA) {
    int i;

    DPRINTF (("TgtDbgPtrace:"));
    if (rdb_debug) {
      for (i = 0; i < data && i < 16; ++i) {
        printf (" %02x", ((char *) addr2)[i] & 0xFF);
      }
      printf ("\n");
    }
  }

  diag = TgtRealPtrace (request, pid, addr, data, addr2);

  DPRINTF (("TgtDbgPtrace: returned %d (%x) errno %d\n",
            diag, diag, getErrno ()));

  if (request == RPT_GETREGS || request == RPT_GETTHREADREGS
      || request == RPT_SETREGS || request == RPT_SETTHREADREGS) {
    /*
     * Use DPRINTF() so as to have the id prefix 
     */
    DPRINTF (("TgtDbgPtrace: (%s) PC = %x, SP = %x, FP = %x\n",
              PtraceName (request),
              ((xdr_regs *) addr)->REG_PC,
              ((xdr_regs *) addr)->REG_SP, ((xdr_regs *) addr)->REG_FP));
  }

  return (diag);
}
#endif /* DDEBUG */