1/* $OpenBSD: fvwrite.c,v 1.22 2024/04/28 14:28:02 millert 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 <limits.h> 35#include <stdio.h> 36#include <stdlib.h> 37#include <string.h> 38#include <unistd.h> 39#include "local.h" 40#include "fvwrite.h" 41 42/* 43 * Write some memory regions. Return zero on success, EOF on error. 44 * 45 * This routine is large and unsightly, but most of the ugliness due 46 * to the three different kinds of output buffering is handled here. 47 */ 48int 49__sfvwrite(FILE *fp, struct __suio *uio) 50{ 51 size_t len; 52 char *p; 53 struct __siov *iov; 54 int w, s; 55 char *nl; 56 int nlknown, nldist; 57 58 if ((len = uio->uio_resid) == 0) 59 return (0); 60 /* make sure we can write */ 61 if (cantwrite(fp)) 62 return (EOF); 63 64#define MIN(a, b) ((a) < (b) ? (a) : (b)) 65#define COPY(n) (void)memcpy(fp->_p, p, n) 66 67 iov = uio->uio_iov; 68 p = iov->iov_base; 69 len = iov->iov_len; 70 iov++; 71#define GETIOV(extra_work) \ 72 while (len == 0) { \ 73 extra_work; \ 74 p = iov->iov_base; \ 75 len = iov->iov_len; \ 76 iov++; \ 77 } 78 if (fp->_flags & __SNBF) { 79 /* 80 * Unbuffered: write up to INT_MAX bytes at a time, to not 81 * truncate the value of len if it is greater than 2^31 bytes. 82 */ 83 do { 84 GETIOV(;); 85 w = (*fp->_write)(fp->_cookie, p, MIN(len, INT_MAX)); 86 if (w <= 0) 87 goto err; 88 p += w; 89 len -= w; 90 } while ((uio->uio_resid -= w) != 0); 91 } else if ((fp->_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 * entire payload directly (without copying) up to a 96 * multiple of the buffer size. 97 * 98 * String output is a special case: write as many bytes 99 * as fit, but pretend we wrote everything. This makes 100 * snprintf() return the number of bytes needed, rather 101 * than the number used, and avoids its write function 102 * (so that the write function can be invalid). 103 */ 104 do { 105 GETIOV(;); 106 if ((fp->_flags & (__SALC | __SSTR)) == 107 (__SALC | __SSTR) && fp->_w < len) { 108 size_t blen = fp->_p - fp->_bf._base; 109 int pgmsk = getpagesize() - 1; 110 unsigned char *_base; 111 int _size; 112 113 /* Round up to nearest page. */ 114 _size = ((blen + len + 1 + pgmsk) & ~pgmsk) - 1; 115 _base = recallocarray(fp->_bf._base, 116 fp->_bf._size + 1, _size + 1, 1); 117 if (_base == NULL) 118 goto err; 119 fp->_w += _size - fp->_bf._size; 120 fp->_bf._base = _base; 121 fp->_bf._size = _size; 122 fp->_p = _base + blen; 123 } 124 w = fp->_w; 125 if (fp->_flags & __SSTR) { 126 if (len < w) 127 w = len; 128 COPY(w); /* copy MIN(fp->_w,len), */ 129 fp->_w -= w; 130 fp->_p += w; 131 w = len; /* but pretend copied all */ 132 } else if (fp->_p > fp->_bf._base && len > w) { 133 /* fill and flush */ 134 COPY(w); 135 /* fp->_w -= w; */ /* unneeded */ 136 fp->_p += w; 137 if (__sflush(fp)) 138 goto err; 139 } else if (len >= (w = fp->_bf._size)) { 140 /* 141 * Write directly up to INT_MAX or greatest 142 * multiple of buffer size (whichever is 143 * smaller), keeping in the memory buffer the 144 * remaining part of payload that is smaller 145 * than buffer size. 146 */ 147 if (w != 0) 148 w = MIN(w * (len / w), INT_MAX); 149 w = (*fp->_write)(fp->_cookie, p, w); 150 if (w <= 0) 151 goto err; 152 } else { 153 /* fill and done */ 154 w = len; 155 COPY(w); 156 fp->_w -= w; 157 fp->_p += w; 158 } 159 p += w; 160 len -= w; 161 } while ((uio->uio_resid -= w) != 0); 162 } else { 163 /* 164 * Line buffered: like fully buffered, but we 165 * must check for newlines. Compute the distance 166 * to the first newline (including the newline), 167 * or `infinity' if there is none, then pretend 168 * that the amount to write is MIN(len,nldist). 169 */ 170 nlknown = 0; 171 nldist = 0; /* XXX just to keep gcc happy */ 172 do { 173 GETIOV(nlknown = 0); 174 if (!nlknown) { 175 nl = memchr(p, '\n', len); 176 nldist = nl ? nl + 1 - p : len + 1; 177 nlknown = 1; 178 } 179 s = MIN(len, nldist); 180 w = fp->_w + fp->_bf._size; 181 if (fp->_p > fp->_bf._base && s > w) { 182 COPY(w); 183 /* fp->_w -= w; */ 184 fp->_p += w; 185 if (__sflush(fp)) 186 goto err; 187 } else if (s >= (w = fp->_bf._size)) { 188 w = (*fp->_write)(fp->_cookie, p, w); 189 if (w <= 0) 190 goto err; 191 } else { 192 w = s; 193 COPY(w); 194 fp->_w -= w; 195 fp->_p += w; 196 } 197 if ((nldist -= w) == 0) { 198 /* copied the newline: flush and forget */ 199 if (__sflush(fp)) 200 goto err; 201 nlknown = 0; 202 } 203 p += w; 204 len -= w; 205 } while ((uio->uio_resid -= w) != 0); 206 } 207 return (0); 208 209err: 210 fp->_flags |= __SERR; 211 return (EOF); 212} 213