FreeTDS Development Group

["Geoff Winkless" <geoff AT farmline.com>]

So for some reason, when MS SQL disconnects you get a SIGPIPE signal when
trying to write to the fd, whereas with Sybase this doesn't happen.

Anyway, this code seems to fix that, I'm not sure if we'd need to put a
SIGPIPE check around the read (do you get bad pipe or does it just return
EIO, EBADF or EINVAL??).

There will probably be more places to add in checks for tds->s.

And I have yet another gripe with gdb. For some reason it crashes when I try
any signal handling at all. Joy. I guess I ought to upgrade gdb... ;-)

Geoff

*** oldwrite.c Tue Jan 25 16:08:07 2000
--- write.c Tue Jan 25 16:03:59 2000
***************
*** 21,26 ****
--- 21,27 ----
  #include "tdsutil.h"
  #include <unistd.h>
  #include <stdlib.h>
+ #include <signal.h> /* GW ADDED */


  static char  software_version[]   = "$Id: write.c,v 1.10 1999/11/28
04:44:31 camber Exp $";
***************
*** 88,95 ****
--- 89,99 ----
   memset(tds->out_buf,'\0',512);
   tds->out_pos=8;
  }
+
  int tds_write_packet(TDSSOCKET *tds,unsigned char final)
  {
+  static int retval;
+  void (*oldsig)(int);
   tds->out_buf[0]=tds->out_flag;
   tds->out_buf[1]=final;
   tds->out_buf[2]=(tds->out_pos)/256;
***************
*** 99,106 ****
   }

          tdsdump_log("Sending packet @ %L\n%D\n", tds->out_buf,
tds->out_pos);

!  write(tds->s,tds->out_buf,tds->out_pos);
   /* for (i=0;i<tds->out_pos;i++) {
    printf ("%d:%d",i,tds->out_buf[i]);
    if (tds->out_buf[i]>=' ' && tds->out_buf[i]<'z')
--- 103,128 ----
   }

   tdsdump_log("Sending packet @ %L\n%D\n", tds->out_buf, tds->out_pos);
+  oldsig=signal (SIGPIPE, SIG_IGN);
+  if (oldsig==SIG_ERR) {
+   fprintf(stderr, "TDS: Warning: Couldn't set SIGPIPE signal to be
ignored\n");
+  }
+  retval=write(tds->s,tds->out_buf,tds->out_pos);
+
+  if (signal(SIGPIPE, oldsig)==SIG_ERR) {
+   fprintf(stderr, "TDS: Warning: Couldn't reset SIGPIPE signal to previous
value\n");
+  }

!  if (retval < 0) {
!   fprintf(stderr, "TDS: Write failed in tds_write_packet\nError: %d
(%s)\n", errno, strerror(errno));
!   tds_client_msg(tds, 10018, 9, 0, 0, "The connection was closed");
!   tds->in_pos=0;
!   tds->in_len=0;
!   close(tds->s);
!   tds->s=0;
!   return 0;
!  }
! /* GW added in check for write() returning <0 and SIGPIPE checking */
   /* for (i=0;i<tds->out_pos;i++) {
    printf ("%d:%d",i,tds->out_buf[i]);
    if (tds->out_buf[i]>=' ' && tds->out_buf[i]<'z')
***************
*** 113,118 ****
  }
  int tds_flush_packet(TDSSOCKET *tds)
  {
!  tds_write_packet(tds,0x01);
!  tds_init_write_buf(tds);
  }
--- 135,141 ----
  }
  int tds_flush_packet(TDSSOCKET *tds)
  {
!  if (tds->s) tds_write_packet(tds,0x01);
!  if (tds->s) tds_init_write_buf(tds);
! /* GW added check for tds->s */
  }