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: head/lib/libc/stdio/fvwrite.c 249810 2013-04-23 14:36:44Z emaste $
  34  */
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include "local.h"
  40
  41 /*
  42  * Write some memory regions.  Return zero on success, EOF on error.
  43  *
  44  * This routine is large and unsightly, but most of the ugliness due
  45  * to the three different kinds of output buffering is handled here.
  46  */
  47 int
  48 __sfvwrite(FILE *fp, struct __suio *uio)
  49 {
  50         size_t len;
  51         char *p;
  52         struct __siov *iov;
  53         int w, s;
  54         char *nl;
  55         int nlknown, nldist;
  56
  57         if (uio->uio_resid == 0)
  58                 return (0);
  59         /* make sure we can write */
  60         if (prepwrite(fp) != 0)
  61                 return (EOF);
  62
  63 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  64 #define COPY(n)   (void)memcpy((void *)fp->pub._p, (void *)p, (size_t)(n))
  65
  66         iov = uio->uio_iov;
  67         p = iov->iov_base;
  68         len = iov->iov_len;
  69         iov++;
  70 #define GETIOV(extra_work) \
  71         while (len == 0) { \
  72                 extra_work; \
  73                 p = iov->iov_base; \
  74                 len = iov->iov_len; \
  75                 iov++; \
  76         }
  77         if (fp->pub._flags & __SNBF) {
  78                 /*
  79                  * Unbuffered: write up to BUFSIZ bytes at a time.
  80                  */
  81                 do {
  82                         GETIOV(;);
  83                         w = _swrite(fp, p, MIN(len, BUFSIZ));
  84                         if (w <= 0)
  85                                 goto err;
  86                         p += w;
  87                         len -= w;
  88                 } while ((uio->uio_resid -= w) != 0);
  89         } else if ((fp->pub._flags & __SLBF) == 0) {
  90                 /*
  91                  * Fully buffered: fill partially full buffer, if any,
  92                  * and then flush.  If there is no partial buffer, write
  93                  * one _bf._size byte chunk directly (without copying).
  94                  *
  95                  * String output is a special case: write as many bytes
  96                  * as fit, but pretend we wrote everything.  This makes
  97                  * snprintf() return the number of bytes needed, rather
  98                  * than the number used, and avoids its write function
  99                  * (so that the write function can be invalid).
 100                  */
 101                 do {
 102                         GETIOV(;);
 103                         if ((fp->pub._flags & (__SALC | __SSTR)) ==
 104                             (__SALC | __SSTR) && fp->pub._w < len) {
 105                                 size_t blen = fp->pub._p - fp->_bf._base;
 106
 107                                 /*
 108                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 109                                  * so we don't call realloc(3) so often.
 110                                  */
 111                                 fp->pub._w = len + 128;
 112                                 fp->_bf._size = blen + len + 128;
 113                                 fp->_bf._base =
 114                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 115                                 if (fp->_bf._base == NULL)
 116                                         goto err;
 117                                 fp->pub._p = fp->_bf._base + blen;
 118                         }
 119                         w = fp->pub._w;
 120                         if (fp->pub._flags & __SSTR) {
 121                                 if (len < w)
 122                                         w = len;
 123                                 if (w > 0) {
 124                                         COPY(w);        /* copy MIN(fp->pub._w,len), */
 125                                         fp->pub._w -= w;
 126                                         fp->pub._p += w;
 127                                 }
 128                                 w = len;        /* but pretend copied all */
 129                         } else if (fp->pub._p > fp->_bf._base && len > w) {
 130                                 /* fill and flush */
 131                                 COPY(w);
 132                                 /* fp->pub._w -= w; */ /* unneeded */
 133                                 fp->pub._p += w;
 134                                 if (__fflush(fp))
 135                                         goto err;
 136                         } else if (len >= (w = fp->_bf._size)) {
 137                                 /* write directly */
 138                                 w = _swrite(fp, p, w);
 139                                 if (w <= 0)
 140                                         goto err;
 141                         } else {
 142                                 /* fill and done */
 143                                 w = len;
 144                                 COPY(w);
 145                                 fp->pub._w -= w;
 146                                 fp->pub._p += w;
 147                         }
 148                         p += w;
 149                         len -= w;
 150                 } while ((uio->uio_resid -= w) != 0);
 151         } else {
 152                 /*
 153                  * Line buffered: like fully buffered, but we
 154                  * must check for newlines.  Compute the distance
 155                  * to the first newline (including the newline),
 156                  * or `infinity' if there is none, then pretend
 157                  * that the amount to write is MIN(len,nldist).
 158                  */
 159                 nlknown = 0;
 160                 nldist = 0;     /* XXX just to keep gcc happy */
 161                 do {
 162                         GETIOV(nlknown = 0);
 163                         if (!nlknown) {
 164                                 nl = memchr((void *)p, '\n', len);
 165                                 nldist = nl ? nl + 1 - p : len + 1;
 166                                 nlknown = 1;
 167                         }
 168                         s = MIN(len, nldist);
 169                         w = fp->pub._w + fp->_bf._size;
 170                         if (fp->pub._p > fp->_bf._base && s > w) {
 171                                 COPY(w);
 172                                 /* fp->pub._w -= w; */
 173                                 fp->pub._p += w;
 174                                 if (__fflush(fp))
 175                                         goto err;
 176                         } else if (s >= (w = fp->_bf._size)) {
 177                                 w = _swrite(fp, p, w);
 178                                 if (w <= 0)
 179                                         goto err;
 180                         } else {
 181                                 w = s;
 182                                 COPY(w);
 183                                 fp->pub._w -= w;
 184                                 fp->pub._p += w;
 185                         }
 186                         if ((nldist -= w) == 0) {
 187                                 /* copied the newline: flush and forget */
 188                                 if (__fflush(fp))
 189                                         goto err;
 190                                 nlknown = 0;
 191                         }
 192                         p += w;
 193                         len -= w;
 194                 } while ((uio->uio_resid -= w) != 0);
 195         }
 196         return (0);
 197
 198 err:
 199         fp->pub._flags |= __SERR;
 200         return (EOF);
 201 }