191 lines
4.2 KiB
C
191 lines
4.2 KiB
C
/*
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* Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
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* All rights reserved.
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*/
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#include <sm/gen.h>
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SM_RCSID("@(#)$Id: setvbuf.c,v 1.32 2001/09/11 04:04:49 gshapiro Exp $")
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#include <stdlib.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sm/io.h>
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#include <sm/heap.h>
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#include <sm/assert.h>
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#include <sm/conf.h>
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#include "local.h"
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/*
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** SM_IO_SETVBUF -- set the buffering type for a file
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**
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** Set one of the different kinds of buffering, optionally including
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** a buffer.
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** If 'size' is == 0 then an "optimal" size will be selected.
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** If 'buf' is == NULL then space will be allocated at 'size'.
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**
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** Parameters:
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** fp -- the file that buffering is to be changed for
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** timeout -- time allowed for completing the function
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** buf -- buffer to use
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** mode -- buffering method to use
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** size -- size of 'buf'
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**
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** Returns:
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** Failure: SM_IO_EOF
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** Success: 0 (zero)
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*/
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int
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sm_io_setvbuf(fp, timeout, buf, mode, size)
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SM_FILE_T *fp;
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int timeout;
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char *buf;
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int mode;
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size_t size;
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{
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int ret, flags;
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size_t iosize;
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int ttyflag;
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int fd;
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struct timeval to;
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SM_REQUIRE_ISA(fp, SmFileMagic);
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/*
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** Verify arguments. The `int' limit on `size' is due to this
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** particular implementation. Note, buf and size are ignored
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** when setting SM_IO_NBF.
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*/
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if (mode != SM_IO_NBF)
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if ((mode != SM_IO_FBF && mode != SM_IO_LBF &&
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mode != SM_IO_NOW) || (int) size < 0)
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return SM_IO_EOF;
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/*
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** Write current buffer, if any. Discard unread input (including
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** ungetc data), cancel line buffering, and free old buffer if
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** malloc()ed. We also clear any eof condition, as if this were
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** a seek.
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*/
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ret = 0;
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SM_CONVERT_TIME(fp, fd, timeout, &to);
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(void) sm_flush(fp, &timeout);
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if (HASUB(fp))
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FREEUB(fp);
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fp->f_r = fp->f_lbfsize = 0;
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flags = fp->f_flags;
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if (flags & SMMBF)
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{
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sm_free((void *) fp->f_bf.smb_base);
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fp->f_bf.smb_base = NULL;
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}
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flags &= ~(SMLBF | SMNBF | SMMBF | SMOPT | SMNPT | SMFEOF | SMNOW |
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SMFBF);
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/* If setting unbuffered mode, skip all the hard work. */
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if (mode == SM_IO_NBF)
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goto nbf;
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/*
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** Find optimal I/O size for seek optimization. This also returns
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** a `tty flag' to suggest that we check isatty(fd), but we do not
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** care since our caller told us how to buffer.
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*/
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flags |= sm_whatbuf(fp, &iosize, &ttyflag);
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if (size == 0)
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{
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buf = NULL; /* force local allocation */
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size = iosize;
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}
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/* Allocate buffer if needed. */
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if (buf == NULL)
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{
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if ((buf = sm_malloc(size)) == NULL)
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{
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/*
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** Unable to honor user's request. We will return
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** failure, but try again with file system size.
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*/
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ret = SM_IO_EOF;
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if (size != iosize)
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{
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size = iosize;
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buf = sm_malloc(size);
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}
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}
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if (buf == NULL)
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{
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/* No luck; switch to unbuffered I/O. */
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nbf:
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fp->f_flags = flags | SMNBF;
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fp->f_w = 0;
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fp->f_bf.smb_base = fp->f_p = fp->f_nbuf;
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fp->f_bf.smb_size = 1;
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return ret;
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}
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flags |= SMMBF;
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}
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/*
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** Kill any seek optimization if the buffer is not the
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** right size.
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**
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** SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
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*/
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if (size != iosize)
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flags |= SMNPT;
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/*
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** Fix up the SM_FILE_T fields, and set sm_cleanup for output flush on
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** exit (since we are buffered in some way).
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*/
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if (mode == SM_IO_LBF)
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flags |= SMLBF;
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else if (mode == SM_IO_NOW)
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flags |= SMNOW;
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else if (mode == SM_IO_FBF)
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flags |= SMFBF;
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fp->f_flags = flags;
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fp->f_bf.smb_base = fp->f_p = (unsigned char *)buf;
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fp->f_bf.smb_size = size;
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/* fp->f_lbfsize is still 0 */
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if (flags & SMWR)
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{
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/*
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** Begin or continue writing: see sm_wsetup(). Note
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** that SMNBF is impossible (it was handled earlier).
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*/
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if (flags & SMLBF)
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{
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fp->f_w = 0;
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fp->f_lbfsize = -fp->f_bf.smb_size;
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}
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else
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fp->f_w = size;
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}
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else
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{
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/* begin/continue reading, or stay in intermediate state */
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fp->f_w = 0;
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}
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atexit(sm_cleanup);
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return ret;
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}
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