src/rmr/si/src/si95/siwait.c

   1 // vim: noet sw=4 ts=4:
   2 /*
   3 ==================================================================================
   4     Copyright (c) 2020-2021 Nokia
   5     Copyright (c) 2020-2021 AT&T Intellectual Property.
   6
   7    Licensed under the Apache License, Version 2.0 (the "License");
   8    you may not use this file except in compliance with the License.
   9    You may obtain a copy of the License at
  10
  11        http://www.apache.org/licenses/LICENSE-2.0
  12
  13    Unless required by applicable law or agreed to in writing, software
  14    distributed under the License is distributed on an "AS IS" BASIS,
  15    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16    See the License for the specific language governing permissions and
  17    limitations under the License.
  18 ==================================================================================
  19 */
  20
  21 /*
  22 **************************************************************************
  23 *  Mnemonic: SIwait
  24 *  Abstract: This  routine will wait for an event to occur on the
  25 *            connections in tplist. When an event is received on a fd
  26 *            the status of the fd is checked and the event handled, driving
  27 *            a callback routine if necessary. The system call poll is usd
  28 *            to wait, and will be interrupted if a signal is caught,
  29 *            therefore the routine will handle any work that is required
  30 *            when a signal is received. The routine continues to loop
  31 *            until the shutdown flag is set, or until there are no open
  32 *            file descriptors on which to wait.
  33 *  Parms:    gptr - Pointer to the global information block
  34 *  Returns:  SI_OK if the caller can continue, SI_ERROR if all sessions have been
  35 *            stopped, or the interface cannot proceed. When SI_ERROR is
  36 *            returned the caller should cleanup and exit immediatly (we
  37 *            have probably received a sigter or sigquit.
  38 *  Date:     28 March 1995
  39 *  Author:   E. Scott Daniels
  40 *
  41 *  Modified: 11 Apr 1995 - To pass execption to select when no keyboard
  42 *            19 Apr 1995 - To call do key to do better keyboard editing
  43 *            18 Aug 1995 - To init kstat to 0 to prevent key hold if
  44 *                          network data pending prior to entry.
  45 *                       31 Jul 2016 - Major formatting clean up in the main while loop.
  46 **************************************************************************
  47 */
  48 #include  "sisetup.h"     //  get the setup stuff
  49 #include "sitransport.h"
  50 #include        <sys/wait.h>
  51
  52 /*
  53         The select timeout is about 300 mu-sec. This is fast enough to add a new
  54         outbound connection to the poll list before the other side responds,
  55         but slow enough so as not to consume excess CPU when idle.
  56 */
  57 #define SI_SELECT_TIMEOUT 300000
  58
  59 #ifndef SYSTEM_UNDER_TEST
  60 #       define SYSTEM_UNDER_TEST 0
  61 #endif
  62
  63 extern int SIwait( struct ginfo_blk *gptr ) {
  64         int fd = -1;                                    //  file descriptor for use in this routine
  65         int ((*cbptr)());                               //  pointer to callback routine to call
  66         int status = SI_OK;                             //  return status
  67         int addrlen = 0;                                //  length of address from recvfrom call
  68         int i;                                                  //  loop index
  69         struct tp_blk *tpptr = NULL;    //  pointer at tp stuff
  70         struct tp_blk *nextone= NULL;   //  point at next block to process in loop
  71         int pstat = 0;                                  //  poll status
  72         struct timeval  timeout;                //  delay to use on select call
  73
  74         if( gptr->magicnum != MAGICNUM ) {                              //  if not a valid ginfo block
  75                 rmr_vlog( RMR_VL_CRIT, "SI95: wait: bad global info struct magic number is wrong\n" );
  76                 return SI_ERROR;
  77         }
  78
  79         if( gptr->flags & GIF_SHUTDOWN ) {                              //  cannot do if we should shutdown
  80                 return SI_ERROR;                                                        //  so just get out
  81         }
  82
  83         do {                                                                    // spin until a callback says to stop (likely never)
  84                 timeout.tv_sec = 0;                                     // must be reset on every call!
  85                 timeout.tv_usec = SI_SELECT_TIMEOUT;
  86
  87                 SIbldpoll( gptr );                                      // poll list is trashed on each pop; must rebuild
  88                 pstat = select( gptr->fdcount, &gptr->readfds, &gptr->writefds, &gptr->execpfds, &timeout );
  89
  90                 if( (pstat < 0 && errno != EINTR)  ) {
  91                         gptr->fdcount = 0;                              //  prevent trying to look at a session
  92                         gptr->flags |= GIF_SHUTDOWN;    //  cause cleanup and exit at end
  93                 }
  94
  95                 if( pstat > 0  &&  (! (gptr->flags & GIF_SHUTDOWN)) ) {
  96                         tpptr = gptr->tplist;
  97                         while( tpptr != NULL ) {
  98                                 nextone = tpptr->next;                          //  prevent issues if we delete the block during loop
  99
 100                                 if( tpptr->fd >= 0 ) {
 101                                         if( tpptr->squeue != NULL && (FD_ISSET( tpptr->fd, &gptr->writefds )) ) {
 102                                                 SIsend( gptr, tpptr );                  //  send if clear to send
 103                                         }
 104
 105                                         if( FD_ISSET( tpptr->fd, &gptr->execpfds ) ) {
 106                                                         ;                               // sunos seems to set the except flag for unknown reasons; ignore it
 107                                         } else {
 108                                                 if( FD_ISSET( tpptr->fd, &gptr->readfds ) ) {                   // ready to read
 109                                                         fd = tpptr->fd;
 110                                                         tpptr->rcvd++;
 111
 112                                                         if( tpptr->flags & TPF_LISTENFD ) {                                     // new session request
 113                                                                 errno=0;
 114                                                                 status = SInewsession( gptr, tpptr );                   // accept connection
 115                                                         } else  {                                                                                       //  data received on a regular port (we support just tcp now
 116                                                                 status = RECV( fd, gptr->rbuf, MAX_RBUF, 0 );   //  read data
 117                                                                 if( status > 0  &&  ! (tpptr->flags & TPF_DRAIN) ) {
 118                                                                         if( (cbptr = gptr->cbtab[SI_CB_CDATA].cbrtn) != NULL ) {
 119                                                                                 status = (*cbptr)( gptr->cbtab[SI_CB_CDATA].cbdata, fd, gptr->rbuf, status );
 120                                                                                 SIcbstat( gptr, status, SI_CB_CDATA );  //  handle cb status
 121                                                                         }
 122                                                                 } else {                                                                                // no bites, but read flagged indicates disconnect
 123                                                                         if( (cbptr = gptr->cbtab[SI_CB_DISC].cbrtn) != NULL ) {
 124                                                                                 status = (*cbptr)( gptr->cbtab[SI_CB_DISC].cbdata, tpptr->fd );
 125                                                                                 SIcbstat( gptr, status, SI_CB_DISC );   //  handle status
 126                                                                         }
 127                                                                         SIterm( gptr, tpptr );                  // close FD and mark block for deletion
 128                                                                 }
 129                                                         }
 130                                                 }
 131                                         }
 132                                 }                                                               //  if still good fd
 133
 134                                 tpptr = nextone;
 135                         }
 136                 }
 137
 138                 if( SYSTEM_UNDER_TEST ) {                                // enabled only during uint testing to prevent blocking
 139                         break;
 140                 }
 141         } while( gptr->tplist != NULL && !(gptr->flags & GIF_SHUTDOWN) );
 142
 143         if( gptr->tplist == NULL )                                      //  indicate all fds closed
 144
 145         if( gptr->flags & GIF_SHUTDOWN ) {                      //  we need to stop for some reason
 146                 status = SI_ERROR;                                              //  status should indicate to user to die
 147                 SIshutdown( gptr );                                             //  clean things up
 148         } else {
 149                 status = SI_OK;                                                 //  user can continue to process
 150         }
 151
 152         return status;
 153 }