/*
 * Copyright (c) 2000-2002, 2004, 2005 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * 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.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include "sm/generic.h"
SM_RCSID("@(#)$Id: fflush.c,v 1.19 2006/07/14 14:42:25 ca Exp $")
#include "sm/error.h"
#include "sm/time.h"
#include "sm/fcntl.h"
#include "sm/string.h"
#include "sm/io.h"
#include "sm/assert.h"
#include "io-int.h"

/*
**  SM_IO_FLUSH -- flush the buffer for a 'fp' to the "file"
**
**  Flush a single file. We don't allow this function to flush
**  all open files when fp==NULL any longer.
**
**	Parameters:
**		fp -- the file pointer buffer to flush
**
**	Results:
**		usual sm_error code
*/

sm_ret_T
sm_io_flush(sm_file_T *fp)
{

	SM_IS_FP(fp);

	if ((f_flags(*fp) & (SMWR | SMRW)) == 0)
	{
		/*
		**  The file is not opened for writing, so it cannot be flushed
		**  (writable means SMWR [write] or SMRW [read/write].
		*/

		return sm_error_perm(SM_EM_IO, EBADF);
	}

	/* Now do the flush */
	return sm_flush(fp);
}

/*
**  SM_FLUSH -- perform the actual flush
**
**  Assumes that 'fp' has been validated before this function called.
**
**	Parameters:
**		fp -- file pointer to be flushed
**
**	Results:
**		usual sm_error code
*/

sm_ret_T
sm_flush(sm_file_T *fp)
{
	uchar *p;
	ssize_t t;
	int n;
	sm_f_flags_T fl;
	sm_ret_T res;

	SM_IS_FP(fp);

	fl = f_flags(*fp);
	if ((fl & SMWR) == 0)
		return SM_SUCCESS;

	if (fl & (SMSTR|SMSTRSTR))
	{
		*f_p(*fp) = '\0';
		return SM_SUCCESS;
	}

	p = f_bfbase(*fp);
	if (p == NULL)
		return SM_SUCCESS;

	n = f_p(*fp) - p;		/* write this much */

	/*
	**  Set these immediately to avoid problems with longjmp and to allow
	**  exchange buffering (via setvbuf) in user write function.
	*/

	f_p(*fp) = p;
	f_w(*fp) = fl & SMNBF ? 0 : f_bfsize(*fp);

	for (; n > 0; n -= t, p += t)
	{
		res = (*f_write(*fp))(fp, p, n, &t);
		if (sm_is_err(res))
		{
			/*
			**  Notice: f_p/f_w are not correct now!
			**  Hence this I/O error is not correctible.
			**  Should we try to fix f_p/f_w? That would require
			**  shifting the buffer content since we may have
			**  written a part.
			*/

			f_flags(*fp) |= SMERR;
#if SM_IO_ERR_VAL
			f_error(*fp) = res;
#endif
			return res;
		}
	}
	return SM_SUCCESS;
}