1/*
2 * Copyright (c) 2000-2002 Sendmail, Inc. and its suppliers.
3 *      All rights reserved.
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 * By using this file, you agree to the terms and conditions set
11 * forth in the LICENSE file which can be found at the top level of
12 * the sendmail distribution.
13 */
14
15#pragma ident	"%Z%%M%	%I%	%E% SMI"
16
17#include <sm/gen.h>
18SM_RCSID("@(#)$Id: wsetup.c,v 1.20 2002/02/07 18:02:45 ca Exp $")
19#include <stdlib.h>
20#include <errno.h>
21#include <sm/io.h>
22#include "local.h"
23
24/*
25**  SM_WSETUP -- check writing is safe
26**
27**  Various output routines call wsetup to be sure it is safe to write,
28**  because either flags does not include SMMWR, or buf is NULL.
29**  Used in the macro "cantwrite" found in "local.h".
30**
31**	Parameters:
32**		fp -- the file pointer
33**
34**	Results:
35**		Failure: SM_IO_EOF and sets errno
36**		Success: 0 (zero)
37*/
38
39int
40sm_wsetup(fp)
41	register SM_FILE_T *fp;
42{
43	/* make sure stdio is set up */
44	if (!Sm_IO_DidInit)
45		sm_init();
46
47	/* If we are not writing, we had better be reading and writing. */
48	if ((fp->f_flags & SMWR) == 0)
49	{
50		if ((fp->f_flags & SMRW) == 0)
51		{
52			errno = EBADF;
53			return SM_IO_EOF;
54		}
55		if (fp->f_flags & SMRD)
56		{
57			/* clobber any ungetc data */
58			if (HASUB(fp))
59				FREEUB(fp);
60
61			/* discard read buffer */
62			fp->f_flags &= ~(SMRD|SMFEOF);
63			fp->f_r = 0;
64			fp->f_p = fp->f_bf.smb_base;
65		}
66		fp->f_flags |= SMWR;
67	}
68
69	/* Make a buffer if necessary, then set w. */
70	if (fp->f_bf.smb_base == NULL)
71		sm_makebuf(fp);
72	if (fp->f_flags & SMLBF)
73	{
74		/*
75		**  It is line buffered, so make lbfsize be -bufsize
76		**  for the sm_putc() macro.  We will change lbfsize back
77		**  to 0 whenever we turn off SMWR.
78		*/
79
80		fp->f_w = 0;
81		fp->f_lbfsize = -fp->f_bf.smb_size;
82	}
83	else
84		fp->f_w = fp->f_flags & SMNBF ? 0 : fp->f_bf.smb_size;
85	return 0;
86}
87