sendmail/libsm/fwrite.c

/*
 * 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: fwrite.c,v 1.22 2001/04/03 01:46:40 ca Exp $")
#include <errno.h>
#include <sm/io.h>
#include <sm/assert.h>
#include "local.h"
#include "fvwrite.h"

/*
**  SM_IO_WRITE -- write to a file pointer
**
**  Parameters:
**      fp -- file pointer writing to
**      timeout -- time to complete the write
**      buf -- location of data to be written
**      size -- number of bytes to be written
**
**  Result:
**      Failure: returns 0 _and_ sets errno
**      Success: returns >=0 with errno unchanged, where the
**          number returned is the number of bytes written.
*/

size_t
sm_io_write(fp, timeout, buf, size)
    SM_FILE_T *fp;
    int timeout;
    const void *buf;
    size_t size;
{
    struct sm_uio uio;
    struct sm_iov iov;

    SM_REQUIRE_ISA(fp, SmFileMagic);

    if (fp->f_write == NULL)
    {
        errno = ENODEV;
        return 0;
    }

    iov.iov_base = (void *) buf;
    uio.uio_resid = iov.iov_len = size;
    uio.uio_iov = &iov;
    uio.uio_iovcnt = 1;

    /* The usual case is success (sm_fvwrite returns 0) */
    if (sm_fvwrite(fp, timeout, &uio) == 0)
        return size;

    /* else return number of bytes actually written */
    return size - uio.uio_resid;
}