lib/libc/stdio/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. 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  * @(#)fvwrite.c        8.1 (Berkeley) 6/4/93
  33  * $FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.18 2007/01/09 00:28:06 imp Exp $
  34  * $DragonFly: src/lib/libc/stdio/fvwrite.c,v 1.7 2005/07/23 20:23:06 joerg Exp $
  35  */
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include "local.h"
  41 #include "priv_stdio.h"
  42
  43 /*
  44  * Write some memory regions.  Return zero on success, EOF on error.
  45  *
  46  * This routine is large and unsightly, but most of the ugliness due
  47  * to the three different kinds of output buffering is handled here.
  48  */
  49 int
  50 __sfvwrite(FILE *fp, struct __suio *uio)
  51 {
  52         size_t len;
  53         char *p;
  54         struct __siov *iov;
  55         int w, s;
  56         char *nl;
  57         int nlknown, nldist;
  58
  59         if ((len = uio->uio_resid) == 0)
  60                 return (0);
  61         /* make sure we can write */
  62         if (prepwrite(fp) != 0)
  63                 return (EOF);
  64
  65 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
  66 #define COPY(n)         memcpy((void *)fp->pub._p, (void *)p, (size_t)(n))
  67
  68         iov = uio->uio_iov;
  69         p = iov->iov_base;
  70         len = iov->iov_len;
  71         iov++;
  72 #define GETIOV(extra_work)              \
  73         while (len == 0) {              \
  74                 extra_work;             \
  75                 p = iov->iov_base;      \
  76                 len = iov->iov_len;     \
  77                 iov++;                  \
  78         }
  79         if (fp->pub._flags & __SNBF) {
  80                 /*
  81                  * Unbuffered: write up to BUFSIZ bytes at a time.
  82                  */
  83                 do {
  84                         GETIOV(;);
  85                         w = _swrite(fp, p, MIN(len, BUFSIZ));
  86                         if (w <= 0)
  87                                 goto err;
  88                         p += w;
  89                         len -= w;
  90                 } while ((uio->uio_resid -= w) != 0);
  91         } else if ((fp->pub._flags & __SLBF) == 0) {
  92                 /*
  93                  * Fully buffered: fill partially full buffer, if any,
  94                  * and then flush.  If there is no partial buffer, write
  95                  * one _bf._size byte chunk directly (without copying).
  96                  *
  97                  * String output is a special case: write as many bytes
  98                  * as fit, but pretend we wrote everything.  This makes
  99                  * snprintf() return the number of bytes needed, rather
 100                  * than the number used, and avoids its write function
 101                  * (so that the write function can be invalid).
 102                  */
 103                 do {
 104                         GETIOV(;);
 105                         if ((fp->pub._flags & (__SALC | __SSTR)) ==
 106                             (__SALC | __SSTR) && fp->pub._w < len) {
 107                                 size_t blen = fp->pub._p - fp->_bf._base;
 108
 109                                 /*
 110                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 111                                  * so we don't call realloc(3) so often.
 112                                  */
 113                                 fp->pub._w = len + 128;
 114                                 fp->_bf._size = blen + len + 128;
 115                                 fp->_bf._base =
 116                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 117                                 if (fp->_bf._base == NULL)
 118                                         goto err;
 119                                 fp->pub._p = fp->_bf._base + blen;
 120                         }
 121                         w = fp->pub._w;
 122                         if (fp->pub._flags & __SSTR) {
 123                                 if (len < w)
 124                                         w = len;
 125                                 if (w > 0) {
 126                                         COPY(w);        /* copy MIN(fp->pub._w, len), */
 127                                         fp->pub._w -= w;
 128                                         fp->pub._p += w;
 129                                 }
 130                                 w = len;        /* but pretend copied all */
 131                         } else if (fp->pub._p > fp->_bf._base && len > w) {
 132                                 /* fill and flush */
 133                                 COPY(w);
 134                                 /* fp->pub._w -= w; */ /* unneeded */
 135                                 fp->pub._p += w;
 136                                 if (__fflush(fp))
 137                                         goto err;
 138                         } else if (len >= (w = fp->_bf._size)) {
 139                                 /* write directly */
 140                                 w = _swrite(fp, p, w);
 141                                 if (w <= 0)
 142                                         goto err;
 143                         } else {
 144                                 /* fill and done */
 145                                 w = len;
 146                                 COPY(w);
 147                                 fp->pub._w -= w;
 148                                 fp->pub._p += w;
 149                         }
 150                         p += w;
 151                         len -= w;
 152                 } while ((uio->uio_resid -= w) != 0);
 153         } else {
 154                 /*
 155                  * Line buffered: like fully buffered, but we
 156                  * must check for newlines.  Compute the distance
 157                  * to the first newline (including the newline),
 158                  * or `infinity' if there is none, then pretend
 159                  * that the amount to write is MIN(len,nldist).
 160                  */
 161                 nlknown = 0;
 162                 nldist = 0;     /* XXX just to keep gcc happy */
 163                 do {
 164                         GETIOV(nlknown = 0);
 165                         if (!nlknown) {
 166                                 nl = memchr((void *)p, '\n', len);
 167                                 nldist = nl ? nl + 1 - p : len + 1;
 168                                 nlknown = 1;
 169                         }
 170                         s = MIN(len, nldist);
 171                         w = fp->pub._w + fp->_bf._size;
 172                         if (fp->pub._p > fp->_bf._base && s > w) {
 173                                 COPY(w);
 174                                 /* fp->pub._w -= w; */
 175                                 fp->pub._p += w;
 176                                 if (__fflush(fp))
 177                                         goto err;
 178                         } else if (s >= (w = fp->_bf._size)) {
 179                                 w = _swrite(fp, p, w);
 180                                 if (w <= 0)
 181                                         goto err;
 182                         } else {
 183                                 w = s;
 184                                 COPY(w);
 185                                 fp->pub._w -= w;
 186                                 fp->pub._p += w;
 187                         }
 188                         if ((nldist -= w) == 0) {
 189                                 /* copied the newline: flush and forget */
 190                                 if (__fflush(fp))
 191                                         goto err;
 192                                 nlknown = 0;
 193                         }
 194                         p += w;
 195                         len -= w;
 196                 } while ((uio->uio_resid -= w) != 0);
 197         }
 198         return (0);
 199
 200 err:
 201         fp->pub._flags |= __SERR;
 202         return (EOF);
 203 }