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/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
#include "mysys_priv.h"
#include "mysys_err.h"
#include <my_base.h>
#include <errno.h>
/*
Read a chunk of bytes from a file with retry's if needed
The parameters are:
File descriptor
Buffer to hold at least Count bytes
Bytes to read
Flags on what to do on error
Return:
-1 on error
0 if flag has bits MY_NABP or MY_FNABP set
N number of bytes read.
*/
size_t my_read(File Filedes, uchar *Buffer, size_t Count, myf MyFlags)
{
size_t readbytes, save_count= 0;
DBUG_ENTER("my_read");
DBUG_PRINT("my",("fd: %d Buffer: %p Count: %lu MyFlags: %lu",
Filedes, Buffer, (ulong) Count, MyFlags));
if (!(MyFlags & (MY_WME | MY_FAE | MY_FNABP)))
MyFlags|= my_global_flags;
for (;;)
{
errno= 0; /* Linux, Windows don't reset this on EOF/success */
#ifdef _WIN32
readbytes= my_win_read(Filedes, Buffer, Count);
#else
readbytes= read(Filedes, Buffer, Count);
#endif
DBUG_EXECUTE_IF ("simulate_file_read_error",
{
errno= ENOSPC;
readbytes= (size_t) -1;
DBUG_SET("-d,simulate_file_read_error");
DBUG_SET("-d,simulate_my_b_fill_error");
});
if (readbytes != Count)
{
int got_errno= my_errno= errno;
DBUG_PRINT("warning",("Read only %d bytes off %lu from %d, errno: %d",
(int) readbytes, (ulong) Count, Filedes,
got_errno));
if (got_errno == 0 || (readbytes != (size_t) -1 &&
(MyFlags & (MY_NABP | MY_FNABP))))
my_errno= HA_ERR_FILE_TOO_SHORT;
if ((readbytes == 0 || (int) readbytes == -1) && got_errno == EINTR)
{
DBUG_PRINT("debug", ("my_read() was interrupted and returned %ld",
(long) readbytes));
continue; /* Interrupted */
}
/* Do a read retry if we didn't get enough data on first read */
if (readbytes != (size_t) -1 && readbytes != 0 &&
(MyFlags & MY_FULL_IO))
{
Buffer+= readbytes;
Count-= readbytes;
save_count+= readbytes;
continue;
}
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
{
if (readbytes == (size_t) -1)
my_error(EE_READ,
MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))),
my_filename(Filedes), got_errno);
else if (MyFlags & (MY_NABP | MY_FNABP))
my_error(EE_EOFERR,
MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))),
my_filename(Filedes), got_errno);
}
if (readbytes == (size_t) -1 ||
((MyFlags & (MY_FNABP | MY_NABP)) && !(MyFlags & MY_FULL_IO)))
DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
}
if (MyFlags & (MY_NABP | MY_FNABP))
readbytes= 0; /* Ok on read */
else
readbytes+= save_count;
break;
}
DBUG_RETURN(readbytes);
} /* my_read */
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