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/*
* 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.
*/
#include <sm/gen.h>
SM_RCSID("@(#)$Id: fread.c,v 1.28 2001/09/11 04:04:48 gshapiro Exp $")
#include <string.h>
#include <errno.h>
#include <sm/io.h>
#include <sm/assert.h>
#include "local.h"
/*
** SM_IO_READ -- read data from the file pointer
**
** Parameters:
** fp -- file pointer to read from
** timeout -- time to complete the read
** buf -- location to place read data
** size -- size of each chunk of data
**
** Returns:
** Failure: returns 0 (zero) _and_ sets errno
** Success: returns the number of whole chunks read.
**
** A read returning 0 (zero) is only an indication of error when errno
** has been set.
*/
size_t
sm_io_read(fp, timeout, buf, size)
SM_FILE_T *fp;
int timeout;
void *buf;
size_t size;
{
register size_t resid = size;
register char *p;
register int r;
SM_REQUIRE_ISA(fp, SmFileMagic);
if (fp->f_read == NULL)
{
errno = ENODEV;
return 0;
}
/*
** The ANSI standard requires a return value of 0 for a count
** or a size of 0. Peculiarily, it imposes no such requirements
** on fwrite; it only requires read to be broken.
*/
if (resid == 0)
return 0;
if (fp->f_r < 0)
fp->f_r = 0;
p = buf;
while ((int) resid > (r = fp->f_r))
{
(void) memcpy((void *) p, (void *) fp->f_p, (size_t) r);
fp->f_p += r;
/* fp->f_r = 0 ... done in sm_refill */
p += r;
resid -= r;
if ((fp->f_flags & SMNOW) != 0 && r > 0)
{
/*
** Take whatever we have available. Spend no more time
** trying to get all that has been requested.
** This is needed on some file types (such as
** SASL) that would jam when given extra, untimely
** reads.
*/
fp->f_r -= r;
return size - resid;
}
if (sm_refill(fp, timeout) != 0)
{
/* no more input: return partial result */
return size - resid;
}
}
(void) memcpy((void *) p, (void *) fp->f_p, resid);
fp->f_r -= resid;
fp->f_p += resid;
return size;
}
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