stdio/FreeBSD/fvwrite.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.19 2009/11/25 04:21:42 wollman Exp $");
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include "local.h"
  43 #include "fvwrite.h"
  44
  45 /*
  46  * Write some memory regions.  Return zero on success, EOF on error.
  47  *
  48  * This routine is large and unsightly, but most of the ugliness due
  49  * to the three different kinds of output buffering is handled here.
  50  */
  51 int
  52 __sfvwrite(fp, uio)
  53         FILE *fp;
  54         struct __suio *uio;
  55 {
  56         size_t len;
  57         char *p;
  58         struct __siov *iov;
  59         int w, s;
  60         char *nl;
  61         int nlknown, nldist;
  62
  63         if (uio->uio_resid == 0)
  64                 return (0);
  65         /* make sure we can write */
  66         if (prepwrite(fp) != 0)
  67                 return (EOF);
  68
  69 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  70 #define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
  71
  72         iov = uio->uio_iov;
  73         p = iov->iov_base;
  74         len = iov->iov_len;
  75         iov++;
  76 #define GETIOV(extra_work) \
  77         while (len == 0) { \
  78                 extra_work; \
  79                 p = iov->iov_base; \
  80                 len = iov->iov_len; \
  81                 iov++; \
  82         }
  83         if (fp->_flags & __SNBF) {
  84                 /*
  85                  * Unbuffered: write up to BUFSIZ bytes at a time.
  86                  */
  87                 do {
  88                         GETIOV(;);
  89                         w = _swrite(fp, p, MIN(len, BUFSIZ));
  90                         if (w <= 0)
  91                                 goto err;
  92                         p += w;
  93                         len -= w;
  94                 } while ((uio->uio_resid -= w) != 0);
  95         } else if ((fp->_flags & __SLBF) == 0) {
  96                 /*
  97                  * Fully buffered: fill partially full buffer, if any,
  98                  * and then flush.  If there is no partial buffer, write
  99                  * one _bf._size byte chunk directly (without copying).
 100                  *
 101                  * String output is a special case: write as many bytes
 102                  * as fit, but pretend we wrote everything.  This makes
 103                  * snprintf() return the number of bytes needed, rather
 104                  * than the number used, and avoids its write function
 105                  * (so that the write function can be invalid).
 106                  */
 107                 do {
 108                         GETIOV(;);
 109                         if ((fp->_flags & (__SALC | __SSTR)) ==
 110                             (__SALC | __SSTR) && fp->_w < len) {
 111                                 size_t blen = fp->_p - fp->_bf._base;
 112
 113                                 /*
 114                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 115                                  * so we don't call realloc(3) so often.
 116                                  */
 117                                 fp->_w = len + 128;
 118                                 fp->_bf._size = blen + len + 128;
 119                                 fp->_bf._base =
 120                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 121                                 if (fp->_bf._base == NULL)
 122                                         goto err;
 123                                 fp->_p = fp->_bf._base + blen;
 124                         }
 125                         w = fp->_w;
 126                         if (fp->_flags & __SSTR) {
 127                                 if (len < w)
 128                                         w = len;
 129                                 if (w > 0) {
 130                                         COPY(w);        /* copy MIN(fp->_w,len), */
 131                                         fp->_w -= w;
 132                                         fp->_p += w;
 133                                 }
 134                                 w = len;        /* but pretend copied all */
 135                         } else if (fp->_p > fp->_bf._base && len > w) {
 136                                 /* fill and flush */
 137                                 COPY(w);
 138                                 /* fp->_w -= w; */ /* unneeded */
 139                                 fp->_p += w;
 140                                 if (__fflush(fp))
 141                                         goto err;
 142                         } else if (len >= (w = fp->_bf._size)) {
 143                                 /* write directly */
 144                                 w = _swrite(fp, p, w);
 145                                 if (w <= 0)
 146                                         goto err;
 147                         } else {
 148                                 /* fill and done */
 149                                 w = len;
 150                                 COPY(w);
 151                                 fp->_w -= w;
 152                                 fp->_p += w;
 153                         }
 154                         p += w;
 155                         len -= w;
 156                 } while ((uio->uio_resid -= w) != 0);
 157         } else {
 158                 /*
 159                  * Line buffered: like fully buffered, but we
 160                  * must check for newlines.  Compute the distance
 161                  * to the first newline (including the newline),
 162                  * or `infinity' if there is none, then pretend
 163                  * that the amount to write is MIN(len,nldist).
 164                  */
 165                 nlknown = 0;
 166                 nldist = 0;     /* XXX just to keep gcc happy */
 167                 do {
 168                         GETIOV(nlknown = 0);
 169                         if (!nlknown) {
 170                                 nl = memchr((void *)p, '\n', len);
 171                                 nldist = nl ? nl + 1 - p : len + 1;
 172                                 nlknown = 1;
 173                         }
 174                         s = MIN(len, nldist);
 175                         w = fp->_w + fp->_bf._size;
 176                         if (fp->_p > fp->_bf._base && s > w) {
 177                                 COPY(w);
 178                                 /* fp->_w -= w; */
 179                                 fp->_p += w;
 180                                 if (__fflush(fp))
 181                                         goto err;
 182                         } else if (s >= (w = fp->_bf._size)) {
 183                                 w = _swrite(fp, p, w);
 184                                 if (w <= 0)
 185                                         goto err;
 186                         } else {
 187                                 w = s;
 188                                 COPY(w);
 189                                 fp->_w -= w;
 190                                 fp->_p += w;
 191                         }
 192                         if ((nldist -= w) == 0) {
 193                                 /* copied the newline: flush and forget */
 194                                 if (__fflush(fp))
 195                                         goto err;
 196                                 nlknown = 0;
 197                         }
 198                         p += w;
 199                         len -= w;
 200                 } while ((uio->uio_resid -= w) != 0);
 201         }
 202         return (0);
 203
 204 err:
 205         fp->_flags |= __SERR;
 206         return (EOF);
 207 }