/* $NetBSD: fvwrite.c,v 1.31 2024/03/29 22:39:41 christos Exp $ */ /*- * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Chris Torek. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) #if 0 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93"; #else __RCSID("$NetBSD: fvwrite.c,v 1.31 2024/03/29 22:39:41 christos Exp $"); #endif #endif /* LIBC_SCCS and not lint */ #include <assert.h> #include <stddef.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "reentrant.h" #include "local.h" #include "fvwrite.h" /* * Write some memory regions. Return zero on success, EOF on error. * * This routine is large and unsightly, but most of the ugliness due * to the three different kinds of output buffering is handled here. */ int __sfvwrite(FILE *fp, struct __suio *uio) { size_t len; char *p; struct __siov *iov; int s; ssize_t w; char *nl; size_t nlknown, nldist; _DIAGASSERT(fp != NULL); _DIAGASSERT(uio != NULL); if ((ssize_t)uio->uio_resid < 0) { errno = EINVAL; return EOF; } if (uio->uio_resid == 0) return 0; /* make sure we can write */ if (cantwrite(fp)) { errno = EBADF; return EOF; } #define MIN(a, b) ((a) < (b) ? (a) : (b)) #define COPY(n) (void)memcpy(fp->_p, p, (size_t)(n)) iov = uio->uio_iov; p = iov->iov_base; len = iov->iov_len; iov++; #define GETIOV(extra_work) \ while (len == 0) { \ extra_work; \ p = iov->iov_base; \ len = iov->iov_len; \ iov++; \ } if (fp->_flags & __SNBF) { /* * Unbuffered: write up to INT_MAX bytes at a time, to not * truncate the value of len if it is greater than 2^31 bytes. */ do { GETIOV(;); w = (*fp->_write)(fp->_cookie, p, MIN(len, INT_MAX)); if (w <= 0) goto err; p += w; len -= w; } while ((uio->uio_resid -= w) != 0); } else if ((fp->_flags & __SLBF) == 0) { /* * Fully buffered: fill partially full buffer, if any, * and then flush. If there is no partial buffer, write * entire payload directly (without copying) up to a multiple * of the buffer size. * * String output is a special case: write as many bytes * as fit, but pretend we wrote everything. This makes * snprintf() return the number of bytes needed, rather * than the number used, and avoids its write function * (so that the write function can be invalid). */ do { GETIOV(;); if ((fp->_flags & (__SALC | __SSTR)) == (__SALC | __SSTR) && (size_t)fp->_w < len) { ptrdiff_t blen = fp->_p - fp->_bf._base; unsigned char *_base; int _size; /* Allocate space exponentially. */ _size = fp->_bf._size; do { _size = (_size << 1) + 1; } while ((size_t)_size < blen + len); _base = realloc(fp->_bf._base, (size_t)(_size + 1)); if (_base == NULL) goto err; fp->_w += _size - fp->_bf._size; fp->_bf._base = _base; fp->_bf._size = _size; fp->_p = _base + blen; } w = fp->_w; if (fp->_flags & __SSTR) { if (len < (size_t)w) w = len; COPY(w); /* copy MIN(fp->_w,len), */ fp->_w -= (int)w; fp->_p += w; w = len; /* but pretend copied all */ } else if (fp->_p > fp->_bf._base && len > (size_t)w) { /* fill and flush */ COPY(w); /* fp->_w -= w; */ /* unneeded */ fp->_p += w; if (fflush(fp)) goto err; } else if (len >= (size_t)(w = fp->_bf._size)) { /* * write directly up to INT_MAX or greatest * multiple of buffer size (whatever is * smaller), keeping in the memory buffer the * remaining part of payload that is smaller * than buffer size. */ if (w != 0) w = MIN(w * (len / w), INT_MAX); w = (*fp->_write)(fp->_cookie, p, (size_t)w); if (w <= 0) goto err; } else { /* fill and done */ w = len; COPY(w); fp->_w -= (int)w; fp->_p += w; } p += w; len -= w; } while ((uio->uio_resid -= w) != 0); } else { /* * Line buffered: like fully buffered, but we * must check for newlines. Compute the distance * to the first newline (including the newline), * or `infinity' if there is none, then pretend * that the amount to write is MIN(len,nldist). */ nlknown = 0; nldist = 0; /* XXX just to keep gcc happy */ do { GETIOV(nlknown = 0); if (!nlknown) { nl = memchr(p, '\n', len); nldist = nl ? (size_t)(nl + 1 - p) : len + 1; nlknown = 1; } s = (int)MIN(len, nldist); w = fp->_w + fp->_bf._size; if (fp->_p > fp->_bf._base && s > w) { COPY(w); /* fp->_w -= w; */ fp->_p += w; if (fflush(fp)) goto err; } else if (s >= (w = fp->_bf._size)) { w = (*fp->_write)(fp->_cookie, p, (size_t)w); if (w <= 0) goto err; } else { w = s; COPY(w); fp->_w -= (int)w; fp->_p += w; } if ((nldist -= w) == 0) { /* copied the newline: flush and forget */ if (fflush(fp)) goto err; nlknown = 0; } p += w; len -= w; } while ((uio->uio_resid -= w) != 0); } return 0; err: fp->_flags |= __SERR; return EOF; }
