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. 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  * @(#)fvwrite.c        8.1 (Berkeley) 6/4/93
  37  * $FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.10 1999/08/28 00:01:06 peter Exp $
  38  * $DragonFly: src/lib/libc/stdio/fvwrite.c,v 1.7 2005/07/23 20:23:06 joerg Exp $
  39  */
  40
  41 #include <errno.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include "local.h"
  46 #include "priv_stdio.h"
  47
  48 /*
  49  * Write some memory regions.  Return zero on success, EOF on error.
  50  *
  51  * This routine is large and unsightly, but most of the ugliness due
  52  * to the three different kinds of output buffering is handled here.
  53  */
  54 int
  55 __sfvwrite(FILE *fp, struct __suio *uio)
  56 {
  57         size_t len;
  58         char *p;
  59         struct __siov *iov;
  60         int w, s;
  61         char *nl;
  62         int nlknown, nldist;
  63
  64         if ((len = uio->uio_resid) == 0)
  65                 return (0);
  66         /* make sure we can write */
  67         if (cantwrite(fp)) {
  68                 errno = EBADF;
  69                 return (EOF);
  70         }
  71
  72 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  73 #define COPY(n)   (void)memcpy((void *)fp->pub._p, (void *)p, (size_t)(n))
  74
  75         iov = uio->uio_iov;
  76         p = iov->iov_base;
  77         len = iov->iov_len;
  78         iov++;
  79 #define GETIOV(extra_work) \
  80         while (len == 0) { \
  81                 extra_work; \
  82                 p = iov->iov_base; \
  83                 len = iov->iov_len; \
  84                 iov++; \
  85         }
  86         if (fp->pub._flags & __SNBF) {
  87                 /*
  88                  * Unbuffered: write up to BUFSIZ bytes at a time.
  89                  */
  90                 do {
  91                         GETIOV(;);
  92                         w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
  93                         if (w <= 0)
  94                                 goto err;
  95                         p += w;
  96                         len -= w;
  97                 } while ((uio->uio_resid -= w) != 0);
  98         } else if ((fp->pub._flags & __SLBF) == 0) {
  99                 /*
 100                  * Fully buffered: fill partially full buffer, if any,
 101                  * and then flush.  If there is no partial buffer, write
 102                  * one _bf._size byte chunk directly (without copying).
 103                  *
 104                  * String output is a special case: write as many bytes
 105                  * as fit, but pretend we wrote everything.  This makes
 106                  * snprintf() return the number of bytes needed, rather
 107                  * than the number used, and avoids its write function
 108                  * (so that the write function can be invalid).
 109                  */
 110                 do {
 111                         GETIOV(;);
 112                         if ((fp->pub._flags & (__SALC | __SSTR)) ==
 113                             (__SALC | __SSTR) && fp->pub._w < len) {
 114                                 size_t blen = fp->pub._p - fp->_bf._base;
 115
 116                                 /*
 117                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 118                                  * so we don't call realloc(3) so often.
 119                                  */
 120                                 fp->pub._w = len + 128;
 121                                 fp->_bf._size = blen + len + 128;
 122                                 fp->_bf._base =
 123                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 124                                 if (fp->_bf._base == NULL)
 125                                         goto err;
 126                                 fp->pub._p = fp->_bf._base + blen;
 127                         }
 128                         w = fp->pub._w;
 129                         if (fp->pub._flags & __SSTR) {
 130                                 if (len < w)
 131                                         w = len;
 132                                 if (w > 0) {
 133                                         COPY(w);        /* copy MIN(fp->_w,len), */
 134                                         fp->pub._w -= w;
 135                                         fp->pub._p += w;
 136                                 }
 137                                 w = len;        /* but pretend copied all */
 138                         } else if (fp->pub._p > fp->_bf._base && len > w) {
 139                                 /* fill and flush */
 140                                 COPY(w);
 141                                 /* fp->_w -= w; */ /* unneeded */
 142                                 fp->pub._p += w;
 143                                 if (__fflush(fp))
 144                                         goto err;
 145                         } else if (len >= (w = fp->_bf._size)) {
 146                                 /* write directly */
 147                                 w = (*fp->_write)(fp->_cookie, p, w);
 148                                 if (w <= 0)
 149                                         goto err;
 150                         } else {
 151                                 /* fill and done */
 152                                 w = len;
 153                                 COPY(w);
 154                                 fp->pub._w -= w;
 155                                 fp->pub._p += w;
 156                         }
 157                         p += w;
 158                         len -= w;
 159                 } while ((uio->uio_resid -= w) != 0);
 160         } else {
 161                 /*
 162                  * Line buffered: like fully buffered, but we
 163                  * must check for newlines.  Compute the distance
 164                  * to the first newline (including the newline),
 165                  * or `infinity' if there is none, then pretend
 166                  * that the amount to write is MIN(len,nldist).
 167                  */
 168                 nlknown = 0;
 169                 nldist = 0;     /* XXX just to keep gcc happy */
 170                 do {
 171                         GETIOV(nlknown = 0);
 172                         if (!nlknown) {
 173                                 nl = memchr((void *)p, '\n', len);
 174                                 nldist = nl ? nl + 1 - p : len + 1;
 175                                 nlknown = 1;
 176                         }
 177                         s = MIN(len, nldist);
 178                         w = fp->pub._w + fp->_bf._size;
 179                         if (fp->pub._p > fp->_bf._base && s > w) {
 180                                 COPY(w);
 181                                 /* fp->_w -= w; */
 182                                 fp->pub._p += w;
 183                                 if (__fflush(fp))
 184                                         goto err;
 185                         } else if (s >= (w = fp->_bf._size)) {
 186                                 w = (*fp->_write)(fp->_cookie, p, w);
 187                                 if (w <= 0)
 188                                         goto err;
 189                         } else {
 190                                 w = s;
 191                                 COPY(w);
 192                                 fp->pub._w -= w;
 193                                 fp->pub._p += w;
 194                         }
 195                         if ((nldist -= w) == 0) {
 196                                 /* copied the newline: flush and forget */
 197                                 if (__fflush(fp))
 198                                         goto err;
 199                                 nlknown = 0;
 200                         }
 201                         p += w;
 202                         len -= w;
 203                 } while ((uio->uio_resid -= w) != 0);
 204         }
 205         return (0);
 206
 207 err:
 208         fp->pub._flags |= __SERR;
 209         return (EOF);
 210 }