lib/libc/stdio/fvwrite.c

   1 /*      $NetBSD: fvwrite.c,v 1.18 2009/02/11 23:48:17 lukem Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
  39 #else
  40 __RCSID("$NetBSD: fvwrite.c,v 1.18 2009/02/11 23:48:17 lukem Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <assert.h>
  45 #include <errno.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include "reentrant.h"
  50 #include "local.h"
  51 #include "fvwrite.h"
  52
  53 /*
  54  * Write some memory regions.  Return zero on success, EOF on error.
  55  *
  56  * This routine is large and unsightly, but most of the ugliness due
  57  * to the three different kinds of output buffering is handled here.
  58  */
  59 int
  60 __sfvwrite(fp, uio)
  61         FILE *fp;
  62         struct __suio *uio;
  63 {
  64         int len;
  65         char *p;
  66         struct __siov *iov;
  67         int w, s;
  68         char *nl;
  69         int nlknown, nldist;
  70
  71         _DIAGASSERT(fp != NULL);
  72         _DIAGASSERT(uio != NULL);
  73
  74         if ((int)uio->uio_resid < 0) {
  75                 errno = EINVAL;
  76                 return (EOF);
  77         }
  78         if ((len = uio->uio_resid) == 0)
  79                 return (0);
  80         /* make sure we can write */
  81         if (cantwrite(fp)) {
  82                 errno = EBADF;
  83                 return (EOF);
  84         }
  85
  86 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  87 #define COPY(n)   (void)memcpy(fp->_p, p, (size_t)(n))
  88
  89         iov = uio->uio_iov;
  90         p = iov->iov_base;
  91         len = iov->iov_len;
  92         iov++;
  93 #define GETIOV(extra_work) \
  94         while (len == 0) { \
  95                 extra_work; \
  96                 p = iov->iov_base; \
  97                 len = iov->iov_len; \
  98                 iov++; \
  99         }
 100         if (fp->_flags & __SNBF) {
 101                 /*
 102                  * Unbuffered: write up to BUFSIZ bytes at a time.
 103                  */
 104                 do {
 105                         GETIOV(;);
 106                         w = (*fp->_write)(fp->_cookie, p,
 107                             (int)MIN(len, BUFSIZ));
 108                         if (w <= 0)
 109                                 goto err;
 110                         p += w;
 111                         len -= w;
 112                 } while ((uio->uio_resid -= w) != 0);
 113         } else if ((fp->_flags & __SLBF) == 0) {
 114                 /*
 115                  * Fully buffered: fill partially full buffer, if any,
 116                  * and then flush.  If there is no partial buffer, write
 117                  * one _bf._size byte chunk directly (without copying).
 118                  *
 119                  * String output is a special case: write as many bytes
 120                  * as fit, but pretend we wrote everything.  This makes
 121                  * snprintf() return the number of bytes needed, rather
 122                  * than the number used, and avoids its write function
 123                  * (so that the write function can be invalid).
 124                  */
 125                 do {
 126                         GETIOV(;);
 127                         if ((fp->_flags & (__SALC | __SSTR)) ==
 128                             (__SALC | __SSTR) && fp->_w < len) {
 129                                 int blen = fp->_p - fp->_bf._base;
 130                                 unsigned char *_base;
 131                                 int _size;
 132
 133                                 /* Allocate space exponentially. */
 134                                 _size = fp->_bf._size;
 135                                 do {
 136                                         _size = (_size << 1) + 1;
 137                                 } while (_size < blen + len);
 138                                 _base = realloc(fp->_bf._base,
 139                                     (size_t)(_size + 1));
 140                                 if (_base == NULL)
 141                                         goto err;
 142                                 fp->_w += _size - fp->_bf._size;
 143                                 fp->_bf._base = _base;
 144                                 fp->_bf._size = _size;
 145                                 fp->_p = _base + blen;
 146                         }
 147                         w = fp->_w;
 148                         if (fp->_flags & __SSTR) {
 149                                 if (len < w)
 150                                         w = len;
 151                                 COPY(w);        /* copy MIN(fp->_w,len), */
 152                                 fp->_w -= w;
 153                                 fp->_p += w;
 154                                 w = len;        /* but pretend copied all */
 155                         } else if (fp->_p > fp->_bf._base && len > w) {
 156                                 /* fill and flush */
 157                                 COPY(w);
 158                                 /* fp->_w -= w; */ /* unneeded */
 159                                 fp->_p += w;
 160                                 if (fflush(fp))
 161                                         goto err;
 162                         } else if (len >= (w = fp->_bf._size)) {
 163                                 /* write directly */
 164                                 w = (*fp->_write)(fp->_cookie, p, w);
 165                                 if (w <= 0)
 166                                         goto err;
 167                         } else {
 168                                 /* fill and done */
 169                                 w = len;
 170                                 COPY(w);
 171                                 fp->_w -= w;
 172                                 fp->_p += w;
 173                         }
 174                         p += w;
 175                         len -= w;
 176                 } while ((uio->uio_resid -= w) != 0);
 177         } else {
 178                 /*
 179                  * Line buffered: like fully buffered, but we
 180                  * must check for newlines.  Compute the distance
 181                  * to the first newline (including the newline),
 182                  * or `infinity' if there is none, then pretend
 183                  * that the amount to write is MIN(len,nldist).
 184                  */
 185                 nlknown = 0;
 186                 nldist = 0;     /* XXX just to keep gcc happy */
 187                 do {
 188                         GETIOV(nlknown = 0);
 189                         if (!nlknown) {
 190                                 nl = memchr(p, '\n', (size_t)len);
 191                                 nldist = nl ? nl + 1 - p : len + 1;
 192                                 nlknown = 1;
 193                         }
 194                         s = MIN(len, nldist);
 195                         w = fp->_w + fp->_bf._size;
 196                         if (fp->_p > fp->_bf._base && s > w) {
 197                                 COPY(w);
 198                                 /* fp->_w -= w; */
 199                                 fp->_p += w;
 200                                 if (fflush(fp))
 201                                         goto err;
 202                         } else if (s >= (w = fp->_bf._size)) {
 203                                 w = (*fp->_write)(fp->_cookie, p, w);
 204                                 if (w <= 0)
 205                                         goto err;
 206                         } else {
 207                                 w = s;
 208                                 COPY(w);
 209                                 fp->_w -= w;
 210                                 fp->_p += w;
 211                         }
 212                         if ((nldist -= w) == 0) {
 213                                 /* copied the newline: flush and forget */
 214                                 if (fflush(fp))
 215                                         goto err;
 216                                 nlknown = 0;
 217                         }
 218                         p += w;
 219                         len -= w;
 220                 } while ((uio->uio_resid -= w) != 0);
 221         }
 222         return (0);
 223
 224 err:
 225         fp->_flags |= __SERR;
 226         return (EOF);
 227 }