/*
 * Copyright (c) 2000-2001, 2005, 2006 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/gen.h>
SM_RCSID("@(#)$Id: fflush.c,v 1.45 2006/03/03 22:25:00 ca Exp $")
#include <unistd.h>
#include <errno.h>
#include <sm/time.h>
#include <signal.h>
#include <fcntl.h>
#include <string.h>
#include <sm/io.h>
#include <sm/assert.h>
#include <sm/setjmp.h>
#include "local.h"
#include <sm/conf.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
**              timeout -- time to complete the flush
**
**      Results:
**              Failure: SM_IO_EOF and sets errno
**              Success: 0 (zero)
*/

int
sm_io_flush(fp, timeout)
        register SM_FILE_T *fp;
        int SM_NONVOLATILE timeout;
{
        int fd;
        struct timeval to;

        SM_REQUIRE_ISA(fp, SmFileMagic);

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

                errno = EBADF;
                return SM_IO_EOF;
        }

        SM_CONVERT_TIME(fp, fd, timeout, &to);

        /* Now do the flush */
        return sm_flush(fp, (int *) &timeout);
}

/*
**  SM_FLUSH -- perform the actual flush
**
**  Assumes that 'fp' has been validated before this function called.
**
**      Parameters:
**              fp -- file pointer to be flushed
**              timeout -- max time allowed for flush (milliseconds)
**
**      Results:
**              Success: 0 (zero)
**              Failure: SM_IO_EOF and errno set
**
**      Side Effects:
**              timeout will get updated with the time remaining (if any)
*/

int
sm_flush(fp, timeout)
        register SM_FILE_T *fp;
        int *timeout;
{
        register unsigned char *p;
        register int n, t;
        int fd;

        SM_REQUIRE_ISA(fp, SmFileMagic);

        t = fp->f_flags;
        if ((t & SMWR) == 0)
                return 0;

        if (t & SMSTR)
        {
                *fp->f_p = '\0';
                return 0;
        }

        if ((p = fp->f_bf.smb_base) == NULL)
                return 0;

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

        if ((fd = sm_io_getinfo(fp, SM_IO_WHAT_FD, NULL)) == -1)
        {
                /* can't get an fd, likely internal 'fake' fp */
                errno = 0;
                fd = -1;
        }

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

        fp->f_p = p;
        fp->f_w = t & (SMLBF|SMNBF) ? 0 : fp->f_bf.smb_size; /* implies SMFBF */

        for (; n > 0; n -= t, p += t)
        {
                errno = 0; /* needed to ensure EOF correctly found */

                /* Call the file type's write function */
                t = (*fp->f_write)(fp, (char *)p, n);
                if (t <= 0)
                {
                        if (t == 0 && errno == 0)
                                break; /* EOF found */

                        if (IS_IO_ERROR(fd, t, *timeout))
                        {
                                fp->f_flags |= SMERR;

                                /* errno set by fp->f_write */
                                return SM_IO_EOF;
                        }
                        SM_IO_WR_TIMEOUT(fp, fd, *timeout);
                        t = 0;
                }
        }
        return 0;
}