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 } 227