wsetup.c revision 90792 
1/*
2 * Copyright (c) 2000-2001 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#include <sm/gen.h>
16SM_RCSID("@(#)$Id: wsetup.c,v 1.19 2001/09/11 04:04:49 gshapiro Exp $")
17#include <stdlib.h>
18#include <errno.h>
19#include <sm/io.h>
20#include "local.h"
21
22/*
23**  SM_WSETUP -- check writting is safe
24**
25**  Various output routines call wsetup to be sure it is safe to write,
26**  because either flags does not include SMMWR, or buf is NULL.
27**  Used in the macro "cantwrite" found in "local.h".
28**
29**	Parameters:
30**		fp -- the file pointer
31**
32**	Results:
33**		Failure: SM_IO_EOF and sets errno
34**		Success: 0 (zero)
35*/
36
37int
38sm_wsetup(fp)
39	register SM_FILE_T *fp;
40{
41	/* make sure stdio is set up */
42	if (!Sm_IO_DidInit)
43		sm_init();
44
45	/* If we are not writing, we had better be reading and writing. */
46	if ((fp->f_flags & SMWR) == 0)
47	{
48		if ((fp->f_flags & SMRW) == 0)
49		{
50			errno = EBADF;
51			return SM_IO_EOF;
52		}
53		if (fp->f_flags & SMRD)
54		{
55			/* clobber any ungetc data */
56			if (HASUB(fp))
57				FREEUB(fp);
58			fp->f_flags &= ~(SMRD|SMFEOF);
59			fp->f_r = 0;
60			fp->f_p = fp->f_bf.smb_base;
61		}
62		fp->f_flags |= SMWR;
63	}
64
65	/* Make a buffer if necessary, then set w. */
66	if (fp->f_bf.smb_base == NULL)
67		sm_makebuf(fp);
68	if (fp->f_flags & SMLBF)
69	{
70		/*
71		**  It is line buffered, so make lbfsize be -bufsize
72		**  for the sm_putc() macro.  We will change lbfsize back
73		**  to 0 whenever we turn off SMWR.
74		*/
75
76		fp->f_w = 0;
77		fp->f_lbfsize = -fp->f_bf.smb_size;
78	}
79	else
80		fp->f_w = fp->f_flags & SMNBF ? 0 : fp->f_bf.smb_size;
81	return 0;
82}
83