/*- * 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. */ #if defined(LIBC_SCCS) && !defined(lint) static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.5 2003/06/02 20:18:37 millert Exp $"; #endif /* LIBC_SCCS and not lint */ #include <stdio.h> #include <stdlib.h> #include "local.h" /* * Set one of the three kinds of buffering, optionally including * a buffer. */ int setvbuf(fp, buf, mode, size) register FILE *fp; char *buf; register int mode; register size_t size; { register int ret, flags; size_t iosize; int ttyflag; /* * Verify arguments. The `int' limit on `size' is due to this * particular implementation. Note, buf and size are ignored * when setting _IONBF. */ if (mode != _IONBF) if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) return (EOF); /* * Write current buffer, if any. Discard unread input (including * ungetc data), cancel line buffering, and free old buffer if * malloc()ed. We also clear any eof condition, as if this were * a seek. */ ret = 0; (void)__sflush(fp); if (HASUB(fp)) FREEUB(fp); fp->_r = fp->_lbfsize = 0; flags = fp->_flags; if (flags & __SMBF) free((void *)fp->_bf._base); flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); /* If setting unbuffered mode, skip all the hard work. */ if (mode == _IONBF) goto nbf; /* * Find optimal I/O size for seek optimization. This also returns * a `tty flag' to suggest that we check isatty(fd), but we do not * care since our caller told us how to buffer. */ flags |= __swhatbuf(fp, &iosize, &ttyflag); if (size == 0) { buf = NULL; /* force local allocation */ size = iosize; } /* Allocate buffer if needed. */ if (buf == NULL) { if ((buf = malloc(size)) == NULL) { /* * Unable to honor user's request. We will return * failure, but try again with file system size. */ ret = EOF; if (size != iosize) { size = iosize; buf = malloc(size); } } if (buf == NULL) { /* No luck; switch to unbuffered I/O. */ nbf: fp->_flags = flags | __SNBF; fp->_w = 0; fp->_bf._base = fp->_p = fp->_nbuf; fp->_bf._size = 1; return (ret); } flags |= __SMBF; } /* * Kill any seek optimization if the buffer is not the * right size. * * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? */ if (size != iosize) flags |= __SNPT; /* * Fix up the FILE fields, and set __cleanup for output flush on * exit (since we are buffered in some way). */ if (mode == _IOLBF) flags |= __SLBF; fp->_flags = flags; fp->_bf._base = fp->_p = (unsigned char *)buf; fp->_bf._size = size; /* fp->_lbfsize is still 0 */ if (flags & __SWR) { /* * Begin or continue writing: see __swsetup(). Note * that __SNBF is impossible (it was handled earlier). */ if (flags & __SLBF) { fp->_w = 0; fp->_lbfsize = -fp->_bf._size; } else fp->_w = size; } else { /* begin/continue reading, or stay in intermediate state */ fp->_w = 0; } __atexit_register_cleanup(_cleanup); return (ret); }