usr/src/cmd/sendmail/libsm/fwrite.c

   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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  16
  17 #include <sm/gen.h>
  18 SM_RCSID("@(#)$Id: fwrite.c,v 1.22 2001/04/03 01:46:40 ca Exp $")
  19 #include <errno.h>
  20 #include <sm/io.h>
  21 #include <sm/assert.h>
  22 #include "local.h"
  23 #include "fvwrite.h"
  24
  25 /*
  26 **  SM_IO_WRITE -- write to a file pointer
  27 **
  28 **      Parameters:
  29 **              fp -- file pointer writing to
  30 **              timeout -- time to complete the write
  31 **              buf -- location of data to be written
  32 **              size -- number of bytes to be written
  33 **
  34 **      Result:
  35 **              Failure: returns 0 _and_ sets errno
  36 **              Success: returns >=0 with errno unchanged, where the
  37 **                      number returned is the number of bytes written.
  38 */
  39
  40 size_t
  41 sm_io_write(fp, timeout, buf, size)
  42         SM_FILE_T *fp;
  43         int timeout;
  44         const void *buf;
  45         size_t size;
  46 {
  47         struct sm_uio uio;
  48         struct sm_iov iov;
  49
  50         SM_REQUIRE_ISA(fp, SmFileMagic);
  51
  52         if (fp->f_write == NULL)
  53         {
  54                 errno = ENODEV;
  55                 return 0;
  56         }
  57
  58         iov.iov_base = (void *) buf;
  59         uio.uio_resid = iov.iov_len = size;
  60         uio.uio_iov = &iov;
  61         uio.uio_iovcnt = 1;
  62
  63         /* The usual case is success (sm_fvwrite returns 0) */
  64         if (sm_fvwrite(fp, timeout, &uio) == 0)
  65                 return size;
  66
  67         /* else return number of bytes actually written */
  68         return size - uio.uio_resid;
  69 }