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/* Copyright (c) 2000, 2011, Oracle and/or its affiliates.
Copyright (c) 2011, Monty Program Ab
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 <m_string.h>
#include <errno.h>
#ifndef _WIN32
#include <unistd.h>
#endif
/*
Read a chunk of bytes from a file from a given position
SYNOPSIOS
my_pread()
Filedes File descriptor
Buffer Buffer to read data into
Count Number of bytes to read
offset Position to read from
MyFlags Flags
NOTES
This differs from the normal pread() call in that we don't care
to set the position in the file back to the original position
if the system doesn't support pread().
RETURN
(size_t) -1 Error
# Number of bytes read
*/
size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
myf MyFlags)
{
size_t readbytes, save_count= 0;
DBUG_ENTER("my_pread");
DBUG_PRINT("my",("fd: %d Seek: %llu Buffer: %p Count: %lu MyFlags: %lu",
Filedes, (ulonglong)offset, 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_pread(Filedes, Buffer, Count, offset);
#else
readbytes= pread(Filedes, Buffer, Count, offset);
#endif
if (readbytes != Count)
{
/* We should never read with wrong file descriptor! */
DBUG_ASSERT(readbytes != (size_t)-1 || errno != EBADF);
my_errno= errno;
if (errno == 0 || (readbytes != (size_t) -1 &&
(MyFlags & (MY_NABP | MY_FNABP))))
my_errno= HA_ERR_FILE_TOO_SHORT;
DBUG_PRINT("warning",("Read only %d bytes off %u from %d, errno: %d",
(int) readbytes, (uint) Count,Filedes,my_errno));
if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR)
{
DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
(int) 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;
offset+= 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),my_errno);
else if (MyFlags & (MY_NABP | MY_FNABP))
my_error(EE_EOFERR,
MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))),
my_filename(Filedes),my_errno);
}
if (readbytes == (size_t) -1 || (MyFlags & (MY_FNABP | MY_NABP)))
DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
}
if (MyFlags & (MY_NABP | MY_FNABP))
readbytes= 0; /* Read went ok; Return 0 */
else
readbytes+= save_count;
DBUG_RETURN(readbytes);
}
} /* my_pread */
/*
Write a chunk of bytes to a file at a given position
SYNOPSIOS
my_pwrite()
Filedes File descriptor
Buffer Buffer to write data from
Count Number of bytes to write
offset Position to write to
MyFlags Flags
NOTES
This differs from the normal pwrite() call in that we don't care
to set the position in the file back to the original position
if the system doesn't support pwrite()
RETURN
(size_t) -1 Error
# Number of bytes read
*/
size_t my_pwrite(int Filedes, const uchar *Buffer, size_t Count,
my_off_t offset, myf MyFlags)
{
size_t writtenbytes, written;
uint errors;
DBUG_ENTER("my_pwrite");
DBUG_PRINT("my",("fd: %d Seek: %llu Buffer: %p Count: %lu MyFlags: %lu",
Filedes, (ulonglong)offset, Buffer, (ulong)Count, MyFlags));
errors= 0;
written= 0;
if (!(MyFlags & (MY_WME | MY_FAE | MY_FNABP)))
MyFlags|= my_global_flags;
for (;;)
{
#ifdef _WIN32
writtenbytes= my_win_pwrite(Filedes, Buffer, Count,offset);
#else
writtenbytes= pwrite(Filedes, Buffer, Count, offset);
#endif
if (writtenbytes == Count)
break;
my_errno= errno;
if (writtenbytes != (size_t) -1)
{ /* Safegueard */
written+=writtenbytes;
Buffer+=writtenbytes;
Count-=writtenbytes;
offset+=writtenbytes;
}
DBUG_PRINT("error",("Write only %u bytes", (uint) writtenbytes));
#ifndef NO_BACKGROUND
if (my_thread_var->abort)
MyFlags&= ~ MY_WAIT_IF_FULL; /* End if aborted by user */
if ((my_errno == ENOSPC || my_errno == EDQUOT) &&
(MyFlags & MY_WAIT_IF_FULL))
{
wait_for_free_space(my_filename(Filedes), errors);
errors++;
continue;
}
if ((writtenbytes && writtenbytes != (size_t) -1) || my_errno == EINTR)
continue; /* Retry */
#endif
/* Don't give a warning if it's ok that we only write part of the data */
if (MyFlags & (MY_NABP | MY_FNABP))
{
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
my_error(EE_WRITE, MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))),
my_filename(Filedes),my_errno);
DBUG_RETURN(MY_FILE_ERROR); /* Error on write */
}
break; /* Return bytes written */
}
DBUG_EXECUTE_IF("check", my_seek(Filedes, -1, SEEK_SET, MYF(0)););
if (MyFlags & (MY_NABP | MY_FNABP))
DBUG_RETURN(0); /* Want only errors */
DBUG_RETURN(writtenbytes+written); /* purecov: inspected */
} /* my_pwrite */
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