1 /* $NetBSD: fvwrite.c,v 1.31 2024/03/29 22:39:41 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 1.31 2024/03/29 22:39:41 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 INT_MAX bytes at a time, to not 103 * truncate the value of len if it is greater than 2^31 bytes. 104 */ 105 do { 106 GETIOV(;); 107 w = (*fp->_write)(fp->_cookie, p, MIN(len, INT_MAX)); 108 if (w <= 0) 109 goto err; 110 p += w; 111 len -= w; 112 } while ((uio->uio_resid -= w) != 0); 113 } else if ((fp->_flags & __SLBF) == 0) { 114 /* 115 * Fully buffered: fill partially full buffer, if any, 116 * and then flush. If there is no partial buffer, write 117 * entire payload directly (without copying) up to a multiple 118 * of the buffer size. 119 * 120 * String output is a special case: write as many bytes 121 * as fit, but pretend we wrote everything. This makes 122 * snprintf() return the number of bytes needed, rather 123 * than the number used, and avoids its write function 124 * (so that the write function can be invalid). 125 */ 126 do { 127 GETIOV(;); 128 if ((fp->_flags & (__SALC | __SSTR)) == 129 (__SALC | __SSTR) && (size_t)fp->_w < len) { 130 ptrdiff_t blen = fp->_p - fp->_bf._base; 131 unsigned char *_base; 132 int _size; 133 134 /* Allocate space exponentially. */ 135 _size = fp->_bf._size; 136 do { 137 _size = (_size << 1) + 1; 138 } while ((size_t)_size < blen + len); 139 _base = realloc(fp->_bf._base, 140 (size_t)(_size + 1)); 141 if (_base == NULL) 142 goto err; 143 fp->_w += _size - fp->_bf._size; 144 fp->_bf._base = _base; 145 fp->_bf._size = _size; 146 fp->_p = _base + blen; 147 } 148 w = fp->_w; 149 if (fp->_flags & __SSTR) { 150 if (len < (size_t)w) 151 w = len; 152 COPY(w); /* copy MIN(fp->_w,len), */ 153 fp->_w -= (int)w; 154 fp->_p += w; 155 w = len; /* but pretend copied all */ 156 } else if (fp->_p > fp->_bf._base && len > (size_t)w) { 157 /* fill and flush */ 158 COPY(w); 159 /* fp->_w -= w; */ /* unneeded */ 160 fp->_p += w; 161 if (fflush(fp)) 162 goto err; 163 } else if (len >= (size_t)(w = fp->_bf._size)) { 164 /* 165 * write directly up to INT_MAX or greatest 166 * multiple of buffer size (whatever is 167 * smaller), keeping in the memory buffer the 168 * remaining part of payload that is smaller 169 * than buffer size. 170 */ 171 if (w != 0) 172 w = MIN(w * (len / w), INT_MAX); 173 w = (*fp->_write)(fp->_cookie, p, (size_t)w); 174 if (w <= 0) 175 goto err; 176 } else { 177 /* fill and done */ 178 w = len; 179 COPY(w); 180 fp->_w -= (int)w; 181 fp->_p += w; 182 } 183 p += w; 184 len -= w; 185 } while ((uio->uio_resid -= w) != 0); 186 } else { 187 /* 188 * Line buffered: like fully buffered, but we 189 * must check for newlines. Compute the distance 190 * to the first newline (including the newline), 191 * or `infinity' if there is none, then pretend 192 * that the amount to write is MIN(len,nldist). 193 */ 194 nlknown = 0; 195 nldist = 0; /* XXX just to keep gcc happy */ 196 do { 197 GETIOV(nlknown = 0); 198 if (!nlknown) { 199 nl = memchr(p, '\n', len); 200 nldist = nl ? (size_t)(nl + 1 - p) : len + 1; 201 nlknown = 1; 202 } 203 s = (int)MIN(len, nldist); 204 w = fp->_w + fp->_bf._size; 205 if (fp->_p > fp->_bf._base && s > w) { 206 COPY(w); 207 /* fp->_w -= w; */ 208 fp->_p += w; 209 if (fflush(fp)) 210 goto err; 211 } else if (s >= (w = fp->_bf._size)) { 212 w = (*fp->_write)(fp->_cookie, p, (size_t)w); 213 if (w <= 0) 214 goto err; 215 } else { 216 w = s; 217 COPY(w); 218 fp->_w -= (int)w; 219 fp->_p += w; 220 } 221 if ((nldist -= w) == 0) { 222 /* copied the newline: flush and forget */ 223 if (fflush(fp)) 224 goto err; 225 nlknown = 0; 226 } 227 p += w; 228 len -= w; 229 } while ((uio->uio_resid -= w) != 0); 230 } 231 return 0; 232 233 err: 234 fp->_flags |= __SERR; 235 return EOF; 236 } 237
Indexes created Sat Sep 20 22:09:52 GMT 2025