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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
  39 #endif /* LIBC_SCCS and not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.17 2004/06/08 05:45:48 das Exp $");
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include "local.h"
  47 #include "fvwrite.h"
  48
  49 /*
  50  * Write some memory regions.  Return zero on success, EOF on error.
  51  *
  52  * This routine is large and unsightly, but most of the ugliness due
  53  * to the three different kinds of output buffering is handled here.
  54  */
  55 int
  56 __sfvwrite(fp, uio)
  57         FILE *fp;
  58         struct __suio *uio;
  59 {
  60         size_t len;
  61         char *p;
  62         struct __siov *iov;
  63         int w, s;
  64         char *nl;
  65         int nlknown, nldist;
  66
  67         if ((len = uio->uio_resid) == 0)
  68                 return (0);
  69         /* make sure we can write */
  70         if (prepwrite(fp) != 0)
  71                 return (EOF);
  72
  73 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  74 #define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
  75
  76         iov = uio->uio_iov;
  77         p = iov->iov_base;
  78         len = iov->iov_len;
  79         iov++;
  80 #define GETIOV(extra_work) \
  81         while (len == 0) { \
  82                 extra_work; \
  83                 p = iov->iov_base; \
  84                 len = iov->iov_len; \
  85                 iov++; \
  86         }
  87         if (fp->_flags & __SNBF) {
  88                 /*
  89                  * Unbuffered: write up to BUFSIZ bytes at a time.
  90                  */
  91                 do {
  92                         GETIOV(;);
  93                         w = _swrite(fp, p, MIN(len, BUFSIZ));
  94                         if (w <= 0)
  95                                 goto err;
  96                         p += w;
  97                         len -= w;
  98                 } while ((uio->uio_resid -= w) != 0);
  99         } else if ((fp->_flags & __SLBF) == 0) {
 100                 /*
 101                  * Fully buffered: fill partially full buffer, if any,
 102                  * and then flush.  If there is no partial buffer, write
 103                  * one _bf._size byte chunk directly (without copying).
 104                  *
 105                  * String output is a special case: write as many bytes
 106                  * as fit, but pretend we wrote everything.  This makes
 107                  * snprintf() return the number of bytes needed, rather
 108                  * than the number used, and avoids its write function
 109                  * (so that the write function can be invalid).
 110                  */
 111                 do {
 112                         GETIOV(;);
 113                         if ((fp->_flags & (__SALC | __SSTR)) ==
 114                             (__SALC | __SSTR) && fp->_w < len) {
 115                                 size_t blen = fp->_p - fp->_bf._base;
 116
 117                                 /*
 118                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 119                                  * so we don't call realloc(3) so often.
 120                                  */
 121                                 fp->_w = len + 128;
 122                                 fp->_bf._size = blen + len + 128;
 123                                 fp->_bf._base =
 124                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 125                                 if (fp->_bf._base == NULL)
 126                                         goto err;
 127                                 fp->_p = fp->_bf._base + blen;
 128                         }
 129                         w = fp->_w;
 130                         if (fp->_flags & __SSTR) {
 131                                 if (len < w)
 132                                         w = len;
 133                                 if (w > 0) {
 134                                         COPY(w);        /* copy MIN(fp->_w,len), */
 135                                         fp->_w -= w;
 136                                         fp->_p += w;
 137                                 }
 138                                 w = len;        /* but pretend copied all */
 139                         } else if (fp->_p > fp->_bf._base && len > w) {
 140                                 /* fill and flush */
 141                                 COPY(w);
 142                                 /* fp->_w -= w; */ /* unneeded */
 143                                 fp->_p += w;
 144                                 if (__fflush(fp))
 145                                         goto err;
 146                         } else if (len >= (w = fp->_bf._size)) {
 147                                 /* write directly */
 148                                 w = _swrite(fp, p, w);
 149                                 if (w <= 0)
 150                                         goto err;
 151                         } else {
 152                                 /* fill and done */
 153                                 w = len;
 154                                 COPY(w);
 155                                 fp->_w -= w;
 156                                 fp->_p += w;
 157                         }
 158                         p += w;
 159                         len -= w;
 160                 } while ((uio->uio_resid -= w) != 0);
 161         } else {
 162                 /*
 163                  * Line buffered: like fully buffered, but we
 164                  * must check for newlines.  Compute the distance
 165                  * to the first newline (including the newline),
 166                  * or `infinity' if there is none, then pretend
 167                  * that the amount to write is MIN(len,nldist).
 168                  */
 169                 nlknown = 0;
 170                 nldist = 0;     /* XXX just to keep gcc happy */
 171                 do {
 172                         GETIOV(nlknown = 0);
 173                         if (!nlknown) {
 174                                 nl = memchr((void *)p, '\n', len);
 175                                 nldist = nl ? nl + 1 - p : len + 1;
 176                                 nlknown = 1;
 177                         }
 178                         s = MIN(len, nldist);
 179                         w = fp->_w + fp->_bf._size;
 180                         if (fp->_p > fp->_bf._base && s > w) {
 181                                 COPY(w);
 182                                 /* fp->_w -= w; */
 183                                 fp->_p += w;
 184                                 if (__fflush(fp))
 185                                         goto err;
 186                         } else if (s >= (w = fp->_bf._size)) {
 187                                 w = _swrite(fp, p, w);
 188                                 if (w <= 0)
 189                                         goto err;
 190                         } else {
 191                                 w = s;
 192                                 COPY(w);
 193                                 fp->_w -= w;
 194                                 fp->_p += w;
 195                         }
 196                         if ((nldist -= w) == 0) {
 197                                 /* copied the newline: flush and forget */
 198                                 if (__fflush(fp))
 199                                         goto err;
 200                                 nlknown = 0;
 201                         }
 202                         p += w;
 203                         len -= w;
 204                 } while ((uio->uio_resid -= w) != 0);
 205         }
 206         return (0);
 207
 208 err:
 209         fp->_flags |= __SERR;
 210         return (EOF);
 211 }