1/* $OpenBSD: fvwrite.c,v 1.14 2005/08/08 08:05:36 espie Exp $ */ 2/*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <stdio.h> 35#include <stdlib.h> 36#include <string.h> 37#include <errno.h> 38#include "local.h" 39#include "fvwrite.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__LIBC_HIDDEN__ int 48__sfvwrite(FILE *fp, struct __suio *uio) 49{ 50 size_t len; 51 const char *p; 52 struct __siov *iov; 53 int w, s; 54 char *nl; 55 int nlknown, nldist; 56 57 if ((len = uio->uio_resid) == 0) 58 return (0); 59 /* make sure we can write */ 60 if (cantwrite(fp)) { 61 errno = EBADF; 62 return (EOF); 63 } 64 65#define MIN(a, b) ((a) < (b) ? (a) : (b)) 66#define COPY(n) (void)memcpy((void *)fp->_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->_flags & __SNBF) { 80 /* 81 * Unbuffered: write up to BUFSIZ bytes at a time. 82 */ 83 do { 84 GETIOV(;); 85#if 1 /* BIONIC: don't limit to 1KB writes */ 86 w = (*fp->_write)(fp->_cookie, p, len); 87#else 88 w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ2)); 89#endif 90 if (w <= 0) 91 goto err; 92 p += w; 93 len -= w; 94 } while ((uio->uio_resid -= w) != 0); 95 } else if ((fp->_flags & __SLBF) == 0) { 96 /* 97 * Fully buffered: fill partially full buffer, if any, 98 * and then flush. If there is no partial buffer, write 99 * one _bf._size byte chunk directly (without copying). 100 * 101 * String output is a special case: write as many bytes 102 * as fit, but pretend we wrote everything. This makes 103 * snprintf() return the number of bytes needed, rather 104 * than the number used, and avoids its write function 105 * (so that the write function can be invalid). 106 */ 107 do { 108 GETIOV(;); 109 if ((fp->_flags & (__SALC | __SSTR)) == 110 (__SALC | __SSTR) && fp->_w < (int)len) { 111 size_t blen = fp->_p - fp->_bf._base; 112 unsigned char *_base; 113 int _size; 114 115 /* Allocate space exponentially. */ 116 _size = fp->_bf._size; 117 do { 118 _size = (_size << 1) + 1; 119 } while (_size < (int)(blen + len)); 120 _base = realloc(fp->_bf._base, _size + 1); 121 if (_base == NULL) 122 goto err; 123 fp->_w += _size - fp->_bf._size; 124 fp->_bf._base = _base; 125 fp->_bf._size = _size; 126 fp->_p = _base + blen; 127 } 128 w = fp->_w; 129 if (fp->_flags & __SSTR) { 130 if ((int)len < w) 131 w = len; 132 COPY(w); /* copy MIN(fp->_w,len), */ 133 fp->_w -= w; 134 fp->_p += w; 135 w = len; /* but pretend copied all */ 136 } else if (fp->_p > fp->_bf._base && (int)len > w) { 137 /* fill and flush */ 138 COPY(w); 139 /* fp->_w -= w; */ /* unneeded */ 140 fp->_p += w; 141 if (fflush(fp)) 142 goto err; 143 } else if ((int)len >= (w = fp->_bf._size)) { 144 /* write directly */ 145 w = (*fp->_write)(fp->_cookie, p, w); 146 if (w <= 0) 147 goto err; 148 } else { 149 /* fill and done */ 150 w = len; 151 COPY(w); 152 fp->_w -= w; 153 fp->_p += w; 154 } 155 p += w; 156 len -= w; 157 } while ((uio->uio_resid -= w) != 0); 158 } else { 159 /* 160 * Line buffered: like fully buffered, but we 161 * must check for newlines. Compute the distance 162 * to the first newline (including the newline), 163 * or `infinity' if there is none, then pretend 164 * that the amount to write is MIN(len,nldist). 165 */ 166 nlknown = 0; 167 nldist = 0; /* XXX just to keep gcc happy */ 168 do { 169 GETIOV(nlknown = 0); 170 if (!nlknown) { 171 nl = memchr((void *)p, '\n', len); 172 nldist = nl ? nl + 1 - p : (int)len + 1; 173 nlknown = 1; 174 } 175 s = MIN((int)len, nldist); 176 w = fp->_w + fp->_bf._size; 177 if (fp->_p > fp->_bf._base && s > w) { 178 COPY(w); 179 /* fp->_w -= w; */ 180 fp->_p += w; 181 if (fflush(fp)) 182 goto err; 183 } else if (s >= (w = fp->_bf._size)) { 184 w = (*fp->_write)(fp->_cookie, p, w); 185 if (w <= 0) 186 goto err; 187 } else { 188 w = s; 189 COPY(w); 190 fp->_w -= w; 191 fp->_p += w; 192 } 193 if ((nldist -= w) == 0) { 194 /* copied the newline: flush and forget */ 195 if (fflush(fp)) 196 goto err; 197 nlknown = 0; 198 } 199 p += w; 200 len -= w; 201 } while ((uio->uio_resid -= w) != 0); 202 } 203 return (0); 204 205err: 206 fp->_flags |= __SERR; 207 return (EOF); 208} 209