2.11BSD#431 - /usr/ingres/source/iutil/wrpipe.c

   1: # include   "../ingres.h"
   2: # include   "../pipes.h"
   3: 
   4: /*
   5: **  Buffered Write on Pipe
   6: **
   7: **	The message `msg' of length `n' is buffered and written onto
   8: **	the pipe with UNIX file descriptor `des'.  `Buf' is the addr
   9: **	of the buffer in which buffering is to take place.  If `n' is
  10: **	zero, `msg' is taken to be a null-terminated string of char-
  11: **	acters.  `Mode' gives the operations mode of wrpipe().
  12: **
  13: **	Buffers written with wrpipe() should be read with rdpipe().
  14: **
  15: **	Modes:
  16: **
  17: **	P_PRIME -- Prime the pipe for writing.  This involves clearing
  18: **		out the error field, setting normal status, etc.  In
  19: **		general, it should always be done when you want to
  20: **		start writing.  It need not be done after writing an
  21: **		end-of-pipe (EOP), as this operation automatically
  22: **		resets the pipe.  The "exec_id" field (read by
  23: **		rdpipe(P_EXECID)) is set to `des', and the "func_id"
  24: **		field is set to `n'.
  25: **
  26: **	P_NORM -- Normal mode.  `Msg' is buffered into `buf' and
  27: **		physically written into the pipe as necessary.
  28: **
  29: **	P_END -- Writes an EOP.  Only the first three parameters need
  30: **		be specified.
  31: **
  32: **	P_FLUSH -- Flushes the buffer into the pipe, but does not write
  33: **		an EOP.  In fact, a non-EOP is guaranteed to be
  34: **		written.
  35: **
  36: **	P_WRITE -- Same as P_FLUSH, but the mode is unchanged.  This
  37: **		mode is pretty obscure, and you probably need not use
  38: **		it.
  39: **
  40: **	P_INT -- Writes an interrupt synchronization block into the
  41: **		pipe.  This mode need only be called by resyncpipes()
  42: **		and need not normally concern the user.  It is critical
  43: **		that this mode be called by all processes so that dead-
  44: **		lock or syserrs do not occur.
  45: **
  46: **	P_PARAM -- Copies one byte parameter into structure. Can be
  47: **		read via a call to rdpipe(P_PARAM).
  48: */
  49: 
  50: extern int  write();        /* standard write function */
  51: int     (*Pi_wr_fn)() = &write; /* pipe write function */
  52: 
  53: wrpipe(mode, buf1, des, msg, n)
  54: int     mode;
  55: struct pipfrmt  *buf1;
  56: int     des;
  57: char        *msg;
  58: int     n;
  59: {
  60:     register int        nn;
  61:     extern char     *Proc_name;
  62:     register int        msgl;
  63:     register struct pipfrmt *buf;
  64:     int         flushflg;
  65:     int         i;
  66: 
  67:     buf = buf1;
  68: #	ifdef xATR1
  69:     if (tTf(99, 8))
  70:         printf("\n%s wrpipe md %d buf %u des %d msg %l n %d\n",
  71:             Proc_name, mode, buf, des, msg, n);
  72: #	endif
  73:     nn = msgl = 0;
  74:     flushflg = 0;
  75:     switch (mode)
  76:     {
  77:       case P_PRIME:
  78:         buf->buf_len = buf->pbuf_pt = buf->err_id = buf->param_id = 0;
  79:         buf->hdrstat = NORM_STAT;
  80:         buf->exec_id = des;
  81:         buf->func_id = n;
  82:         return(0);
  83: 
  84:       case P_PARAM:
  85:         buf->param_id = des;
  86:         return (0);
  87: 
  88:       case P_NORM:
  89:         msgl = nn = (n == 0) ? length(msg) + 1 : n;
  90:         break;
  91: 
  92:       case P_END:
  93:         buf->hdrstat = LAST_STAT;
  94:         flushflg++;
  95:         break;
  96: 
  97:       case P_FLUSH:
  98:         buf->hdrstat = NORM_STAT;
  99:         flushflg++;
 100:         break;
 101: 
 102:       case P_WRITE:
 103:         flushflg--;
 104:         break;
 105: 
 106:       case P_INT:
 107:         buf->hdrstat = SYNC_STAT;
 108:         flushflg++;
 109:         break;
 110: 
 111:       default:
 112:         syserr("wrpipe: bad mode %d", mode);
 113:     }
 114: 
 115:     while (nn > 0 || flushflg)
 116:     {
 117:         /* BUFFER OUT DATA */
 118:         while (nn > 0 && buf->pbuf_pt < PBUFSIZ)
 119:             buf->pbuf[buf->pbuf_pt++] = msg[msgl - (nn--)];
 120:         /* WRITE PIPE ? */
 121:         if (buf->pbuf_pt >= PBUFSIZ || flushflg)
 122:         {
 123:             if (flushflg >= 0)
 124:                 buf->buf_len = buf->pbuf_pt;
 125: #			ifdef xATR2
 126:             if (tTf(99, 10))
 127:                 prpipe(buf);
 128: #			endif
 129:             if ((i = (*Pi_wr_fn)(des, buf, HDRSIZ+PBUFSIZ)) < HDRSIZ+PBUFSIZ)
 130:                 syserr("wrpipe: wr err %d %d", i, des);
 131:             buf->pbuf_pt = 0;
 132:             buf->err_id = 0;
 133:             flushflg = 0;
 134:         }
 135:     }
 136: #	ifdef xATR3
 137:     if (tTf(99, 9))
 138:     {
 139:         printf("%s wrpipe ret %d\n", Proc_name, msgl);
 140:     }
 141: #	endif
 142:     return (msgl);
 143: }

Defined functions