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101 lines
2.3 KiB
C
101 lines
2.3 KiB
C
/*
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* Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
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* All rights reserved.
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*/
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#include <sm/gen.h>
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SM_RCSID("@(#)$Id: fread.c,v 1.28 2001/09/11 04:04:48 gshapiro Exp $")
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#include <string.h>
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#include <errno.h>
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#include <sm/io.h>
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#include <sm/assert.h>
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#include "local.h"
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/*
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** SM_IO_READ -- read data from the file pointer
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**
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** Parameters:
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** fp -- file pointer to read from
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** timeout -- time to complete the read
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** buf -- location to place read data
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** size -- size of each chunk of data
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**
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** Returns:
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** Failure: returns 0 (zero) _and_ sets errno
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** Success: returns the number of whole chunks read.
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**
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** A read returning 0 (zero) is only an indication of error when errno
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** has been set.
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*/
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size_t
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sm_io_read(fp, timeout, buf, size)
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SM_FILE_T *fp;
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int timeout;
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void *buf;
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size_t size;
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{
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register size_t resid = size;
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register char *p;
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register int r;
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SM_REQUIRE_ISA(fp, SmFileMagic);
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if (fp->f_read == NULL)
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{
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errno = ENODEV;
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return 0;
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}
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/*
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** The ANSI standard requires a return value of 0 for a count
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** or a size of 0. Peculiarily, it imposes no such requirements
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** on fwrite; it only requires read to be broken.
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*/
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if (resid == 0)
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return 0;
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if (fp->f_r < 0)
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fp->f_r = 0;
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p = buf;
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while ((int) resid > (r = fp->f_r))
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{
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(void) memcpy((void *) p, (void *) fp->f_p, (size_t) r);
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fp->f_p += r;
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/* fp->f_r = 0 ... done in sm_refill */
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p += r;
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resid -= r;
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if ((fp->f_flags & SMNOW) != 0 && r > 0)
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{
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/*
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** Take whatever we have available. Spend no more time
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** trying to get all that has been requested.
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** This is needed on some file types (such as
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** SASL) that would jam when given extra, untimely
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** reads.
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*/
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fp->f_r -= r;
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return size - resid;
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}
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if (sm_refill(fp, timeout) != 0)
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{
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/* no more input: return partial result */
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return size - resid;
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}
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}
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(void) memcpy((void *) p, (void *) fp->f_p, resid);
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fp->f_r -= resid;
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fp->f_p += resid;
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return size;
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}
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