sendmail/libsm/fflush.c

	fflush.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright (c) 2000-2001 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.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: fflush.c,v 1.41 2001/05/15 16:55:27 ca Exp $")
#include <unistd.h>
#include <errno.h>
#include <sys/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);
        }
    }
    return 0;
}