usr/src/cmd/lp/lib/msgs/mread.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  23 /*        All Rights Reserved   */
  24
  25
  26 #ident  "%Z%%M% %I%     %E% SMI"        /* SVr4.0 1.6   */
  27 /* LINTLIBRARY */
  28
  29
  30 #include <errno.h>
  31 #include <fcntl.h>
  32 #include <string.h>
  33 #include <stropts.h>
  34
  35 #include "lp.h"
  36 #include "msgs.h"
  37
  38 extern int      Lp_prio_msg;
  39
  40 /*
  41 **      Function:       int mread( MESG *, char *, int)
  42 **      Args:           message descriptor
  43 **                      message buffer (var)
  44 **                      buffer size
  45 **      Return:         The size of the message in message buffer.
  46 **                      or -1 on error.  Possible errnos are:
  47 **              EINVAL  Bad value for md or msgbuf.
  48 **              E2BIG   Not enough space for message.
  49 **              EPIPE   Far end dropped the connection.
  50 **              ENOMSG  No valid message available on fifo.
  51 **
  52 **      mread examines message descriptor and either calls read3_2
  53 **      to read 3.2 HPI messages or getmsg(2) to read 4.0 HPI messages.
  54 **      If a message is read, it is returned in message buffer.
  55 */
  56
  57 #if     defined(__STDC__)
  58 int mread ( MESG * md, char * msgbuf, int size )
  59 #else
  60 int mread ( md, msgbuf, size )
  61 MESG    *md;
  62 char    *msgbuf;
  63 int     size;
  64 #endif
  65 {
  66     int                 flag = 0;
  67     char                buff [MSGMAX];
  68     struct strbuf       dat;
  69     struct strbuf       ctl;
  70
  71     if (md == NULL || msgbuf == NULL)
  72     {
  73         errno = EINVAL;
  74         return(-1);
  75     }
  76
  77     switch(md->type)
  78     {
  79       case MD_CHILD:
  80       case MD_STREAM:
  81       case MD_BOUND:
  82         if (size <= 0)
  83         {
  84             errno = E2BIG;
  85             return(-1);
  86         }
  87         dat.buf = msgbuf;
  88         dat.maxlen = size;
  89         dat.len = 0;
  90         ctl.buf = buff;
  91         ctl.maxlen = sizeof (buff);
  92         ctl.len = 0;
  93         flag = Lp_prio_msg;
  94         Lp_prio_msg = 0;        /* clean this up so there are no surprises */
  95
  96         if (Getmsg(md, &ctl, &dat, &flag) < 0)
  97         {
  98             if (errno == EBADF)
  99                 errno = EPIPE;
 100             return(-1);
 101         }
 102
 103         if (dat.len == 0)
 104         {
 105             (void) Close(md->readfd);
 106             return(0);
 107         }
 108         break;
 109
 110       case MD_USR_FIFO:
 111       case MD_SYS_FIFO:
 112         if (size < CONTROL_LEN)
 113         {
 114             errno = E2BIG;
 115             return(-1);
 116         }
 117
 118         if (read3_2(md, msgbuf, size) < 0)
 119             return(-1);
 120         break;
 121     }
 122
 123     return((int)msize(msgbuf));
 124 }