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4e92af9f43
Bug#24509 - 2048 file descriptor limit on windows needs increasing, also
WL#3049 - improved Windows I/O
The patch replaces the use of the POSIX I/O interfaces in mysys on Windows with
the Win32 API calls (CreateFile, WriteFile, etc). The Windows HANDLE for the open
file is stored in the my_file_info struct, along with a flag for append mode
because the Windows API does not support opening files in append mode in all cases)
The default max open files has been increased to 16384 and can be increased further
by setting --max-open-files=<value> during the server start.
Another major change in this patch that almost all Windows specific file IO code
has been moved to a new file my_winfile.c, greatly reducing the amount of code
in #ifdef blocks within mysys, thus improving readability.
Minor enhancements:
- my_(f)stat() is changed to use __stati64 structure with 64 file size
and timestamps. It will return correct file size now (C runtime implementation
used to report outdated information)
- my_lock on Windows is prepared to handle additional timeout parameter
- after review : changed __WIN__ to _WIN32 in the new and changed code.
95 lines
3.1 KiB
C
95 lines
3.1 KiB
C
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "mysys_priv.h"
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/*
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Seek to a position in a file.
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ARGUMENTS
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File fd The file descriptor
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my_off_t pos The expected position (absolute or relative)
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int whence A direction parameter and one of
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{SEEK_SET, SEEK_CUR, SEEK_END}
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myf MyFlags MY_THREADSAFE must be set in case my_seek may be mixed
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with my_pread/my_pwrite calls and fd is shared among
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threads.
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DESCRIPTION
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The my_seek function is a wrapper around the system call lseek and
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repositions the offset of the file descriptor fd to the argument
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offset according to the directive whence as follows:
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SEEK_SET The offset is set to offset bytes.
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SEEK_CUR The offset is set to its current location plus offset bytes
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SEEK_END The offset is set to the size of the file plus offset bytes
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RETURN VALUE
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my_off_t newpos The new position in the file.
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MY_FILEPOS_ERROR An error was encountered while performing
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the seek. my_errno is set to indicate the
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actual error.
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*/
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my_off_t my_seek(File fd, my_off_t pos, int whence,
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myf MyFlags __attribute__((unused)))
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{
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os_off_t newpos= -1;
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DBUG_ENTER("my_seek");
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DBUG_PRINT("my",("fd: %d Pos: %llu Whence: %d MyFlags: %d",
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fd, (ulonglong) pos, whence, MyFlags));
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DBUG_ASSERT(pos != MY_FILEPOS_ERROR); /* safety check */
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/*
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Make sure we are using a valid file descriptor!
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*/
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DBUG_ASSERT(fd != -1);
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#if defined (_WIN32)
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newpos= my_win_lseek(fd, pos, whence);
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#else
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newpos= lseek(fd, pos, whence);
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#endif
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if (newpos == (os_off_t) -1)
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{
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my_errno= errno;
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DBUG_PRINT("error",("lseek: %llu errno: %d", (ulonglong) newpos,errno));
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DBUG_RETURN(MY_FILEPOS_ERROR);
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}
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if ((my_off_t) newpos != pos)
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{
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DBUG_PRINT("exit",("pos: %llu", (ulonglong) newpos));
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}
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DBUG_RETURN((my_off_t) newpos);
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} /* my_seek */
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/* Tell current position of file */
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/* ARGSUSED */
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my_off_t my_tell(File fd, myf MyFlags __attribute__((unused)))
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{
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os_off_t pos;
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DBUG_ENTER("my_tell");
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DBUG_PRINT("my",("fd: %d MyFlags: %d",fd, MyFlags));
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DBUG_ASSERT(fd >= 0);
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#if defined (HAVE_TELL) && !defined (_WIN32)
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pos= tell(fd);
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#else
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pos= my_seek(fd, 0L, MY_SEEK_CUR,0);
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#endif
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if (pos == (os_off_t) -1)
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my_errno= errno;
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DBUG_PRINT("exit",("pos: %llu", (ulonglong) pos));
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DBUG_RETURN((my_off_t) pos);
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} /* my_tell */
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