lib/libc/stdio/fvwrite.c

   1 /*      $NetBSD: fvwrite.c,v 1.25 2012/03/27 15:05:42 christos 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 1.25 2012/03/27 15:05:42 christos Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <assert.h>
  45 #include <stddef.h>
  46 #include <errno.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include "reentrant.h"
  51 #include "local.h"
  52 #include "fvwrite.h"
  53
  54 /*
  55  * Write some memory regions.  Return zero on success, EOF on error.
  56  *
  57  * This routine is large and unsightly, but most of the ugliness due
  58  * to the three different kinds of output buffering is handled here.
  59  */
  60 int
  61 __sfvwrite(FILE *fp, struct __suio *uio)
  62 {
  63         size_t len;
  64         char *p;
  65         struct __siov *iov;
  66         int s;
  67         ssize_t w;
  68         char *nl;
  69         size_t nlknown, nldist;
  70
  71         _DIAGASSERT(fp != NULL);
  72         _DIAGASSERT(uio != NULL);
  73
  74         if ((ssize_t)uio->uio_resid < 0) {
  75                 errno = EINVAL;
  76                 return EOF;
  77         }
  78         if (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, MIN(len, BUFSIZ));
 107                         if (w <= 0)
 108                                 goto err;
 109                         p += w;
 110                         len -= w;
 111                 } while ((uio->uio_resid -= w) != 0);
 112         } else if ((fp->_flags & __SLBF) == 0) {
 113                 /*
 114                  * Fully buffered: fill partially full buffer, if any,
 115                  * and then flush.  If there is no partial buffer, write
 116                  * one _bf._size byte chunk directly (without copying).
 117                  *
 118                  * String output is a special case: write as many bytes
 119                  * as fit, but pretend we wrote everything.  This makes
 120                  * snprintf() return the number of bytes needed, rather
 121                  * than the number used, and avoids its write function
 122                  * (so that the write function can be invalid).
 123                  */
 124                 do {
 125                         GETIOV(;);
 126                         if ((fp->_flags & (__SALC | __SSTR)) ==
 127                             (__SALC | __SSTR) && (size_t)fp->_w < len) {
 128                                 ptrdiff_t blen = fp->_p - fp->_bf._base;
 129                                 unsigned char *_base;
 130                                 int _size;
 131
 132                                 /* Allocate space exponentially. */
 133                                 _size = fp->_bf._size;
 134                                 do {
 135                                         _size = (_size << 1) + 1;
 136                                 } while ((size_t)_size < blen + len);
 137                                 _base = realloc(fp->_bf._base,
 138                                     (size_t)(_size + 1));
 139                                 if (_base == NULL)
 140                                         goto err;
 141                                 fp->_w += _size - fp->_bf._size;
 142                                 fp->_bf._base = _base;
 143                                 fp->_bf._size = _size;
 144                                 fp->_p = _base + blen;
 145                         }
 146                         w = fp->_w;
 147                         if (fp->_flags & __SSTR) {
 148                                 if (len < (size_t)w)
 149                                         w = len;
 150                                 COPY(w);        /* copy MIN(fp->_w,len), */
 151                                 fp->_w -= (int)w;
 152                                 fp->_p += w;
 153                                 w = len;        /* but pretend copied all */
 154                         } else if (fp->_p > fp->_bf._base && len > (size_t)w) {
 155                                 /* fill and flush */
 156                                 COPY(w);
 157                                 /* fp->_w -= w; */ /* unneeded */
 158                                 fp->_p += w;
 159                                 if (fflush(fp))
 160                                         goto err;
 161                         } else if (len >= (size_t)(w = fp->_bf._size)) {
 162                                 /* write directly */
 163                                 w = (*fp->_write)(fp->_cookie, p, (size_t)w);
 164                                 if (w <= 0)
 165                                         goto err;
 166                         } else {
 167                                 /* fill and done */
 168                                 w = len;
 169                                 COPY(w);
 170                                 fp->_w -= (int)w;
 171                                 fp->_p += w;
 172                         }
 173                         p += w;
 174                         len -= w;
 175                 } while ((uio->uio_resid -= w) != 0);
 176         } else {
 177                 /*
 178                  * Line buffered: like fully buffered, but we
 179                  * must check for newlines.  Compute the distance
 180                  * to the first newline (including the newline),
 181                  * or `infinity' if there is none, then pretend
 182                  * that the amount to write is MIN(len,nldist).
 183                  */
 184                 nlknown = 0;
 185                 nldist = 0;     /* XXX just to keep gcc happy */
 186                 do {
 187                         GETIOV(nlknown = 0);
 188                         if (!nlknown) {
 189                                 nl = memchr(p, '\n', len);
 190                                 nldist = nl ? (size_t)(nl + 1 - p) : len + 1;
 191                                 nlknown = 1;
 192                         }
 193                         s = (int)MIN(len, nldist);
 194                         w = fp->_w + fp->_bf._size;
 195                         if (fp->_p > fp->_bf._base && s > w) {
 196                                 COPY(w);
 197                                 /* fp->_w -= w; */
 198                                 fp->_p += w;
 199                                 if (fflush(fp))
 200                                         goto err;
 201                         } else if (s >= (w = fp->_bf._size)) {
 202                                 w = (*fp->_write)(fp->_cookie, p, (size_t)w);
 203                                 if (w <= 0)
 204                                         goto err;
 205                         } else {
 206                                 w = s;
 207                                 COPY(w);
 208                                 fp->_w -= (int)w;
 209                                 fp->_p += w;
 210                         }
 211                         if ((nldist -= w) == 0) {
 212                                 /* copied the newline: flush and forget */
 213                                 if (fflush(fp))
 214                                         goto err;
 215                                 nlknown = 0;
 216                         }
 217                         p += w;
 218                         len -= w;
 219                 } while ((uio->uio_resid -= w) != 0);
 220         }
 221         return 0;
 222
 223 err:
 224         fp->_flags |= __SERR;
 225         return EOF;
 226 }