usr/src/lib/libc/port/stdio/setvbuf.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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include "file64.h"
  34 #include "mtlib.h"
  35 #include <sys/types.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <thread.h>
  39 #include <synch.h>
  40 #include "stdiom.h"
  41
  42 int
  43 setvbuf(FILE *iop, char *abuf, int type, size_t size)
  44 {
  45
  46         Uchar   *buf = (Uchar *)abuf;
  47         Uchar *temp;
  48         int     sflag = iop->_flag & _IOMYBUF;
  49         rmutex_t *lk;
  50         int fd = GET_FD(iop);
  51
  52         FLOCKFILE(lk, iop);
  53         iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
  54         switch (type) {
  55         /* note that the flags are the same as the possible values for type */
  56         case _IONBF:
  57                 iop->_flag |= _IONBF;    /* file is unbuffered */
  58 #ifndef _STDIO_ALLOCATE
  59                 if (fd < 2) {
  60                         /* use special buffer for std{in,out} */
  61                         buf = (fd == 0) ? _sibuf : _sobuf;
  62                         size = BUFSIZ;
  63                 } else /* needed for ifdef */
  64 #endif
  65                 if (fd < _NFILE) {
  66                         buf = _smbuf[fd];
  67                         size = _SMBFSZ - PUSHBACK;
  68                 } else
  69                         if ((buf = malloc(_SMBFSZ * sizeof (Uchar))) != NULL) {
  70                                 iop->_flag |= _IOMYBUF;
  71                                 size = _SMBFSZ - PUSHBACK;
  72                         } else {
  73                                 FUNLOCKFILE(lk);
  74                                 return (EOF);
  75                         }
  76                 break;
  77         case _IOLBF:
  78         case _IOFBF:
  79                 iop->_flag |= type;     /* buffer file */
  80                 /*
  81                  * need at least an 8 character buffer for
  82                  * out_of_sync concerns.
  83                  */
  84                 if (size <= _SMBFSZ) {
  85                         size = BUFSIZ;
  86                         buf = NULL;
  87                 }
  88                 if (buf == NULL) {
  89                         if ((buf = malloc(sizeof (Uchar) *
  90                             (size + _SMBFSZ))) != NULL)
  91                                 iop->_flag |= _IOMYBUF;
  92                         else {
  93                                 FUNLOCKFILE(lk);
  94                                 return (EOF);
  95                         }
  96                 }
  97                 else
  98                         size -= _SMBFSZ;
  99                 break;
 100         default:
 101                 FUNLOCKFILE(lk);
 102                 return (EOF);
 103         }
 104         if (iop->_base != NULL && sflag)
 105                 free((char *)iop->_base - PUSHBACK);
 106         temp = buf + PUSHBACK;
 107         iop->_base = temp;
 108         _setbufend(iop, temp + size);
 109         iop->_ptr = temp;
 110         iop->_cnt = 0;
 111         FUNLOCKFILE(lk);
 112         return (0);
 113 }