MGMDB/MySQL/my_file.c
2011-10-02 20:48:43 -05:00

135 lines
3.8 KiB
C

/* Copyright (C) 2000 MySQL 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "mysys_priv.h"
#include "my_static.h"
#include <m_string.h>
/*
set how many open files we want to be able to handle
SYNOPSIS
set_maximum_open_files()
max_file_limit Files to open
NOTES
The request may not fulfilled becasue of system limitations
RETURN
Files available to open.
May be more or less than max_file_limit!
*/
#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
#ifndef RLIM_INFINITY
#define RLIM_INFINITY ((uint) 0xffffffff)
#endif
static uint set_max_open_files(uint max_file_limit)
{
struct rlimit rlimit;
uint old_cur;
DBUG_ENTER("set_max_open_files");
DBUG_PRINT("enter",("files: %u", max_file_limit));
if (!getrlimit(RLIMIT_NOFILE,&rlimit))
{
old_cur= (uint) rlimit.rlim_cur;
DBUG_PRINT("info", ("rlim_cur: %u rlim_max: %u",
(uint) rlimit.rlim_cur,
(uint) rlimit.rlim_max));
if (rlimit.rlim_cur == RLIM_INFINITY)
rlimit.rlim_cur = max_file_limit;
if (rlimit.rlim_cur >= max_file_limit)
DBUG_RETURN(rlimit.rlim_cur); /* purecov: inspected */
rlimit.rlim_cur= rlimit.rlim_max= max_file_limit;
if (setrlimit(RLIMIT_NOFILE, &rlimit))
max_file_limit= old_cur; /* Use original value */
else
{
rlimit.rlim_cur= 0; /* Safety if next call fails */
(void) getrlimit(RLIMIT_NOFILE,&rlimit);
DBUG_PRINT("info", ("rlim_cur: %u", (uint) rlimit.rlim_cur));
if (rlimit.rlim_cur) /* If call didn't fail */
max_file_limit= (uint) rlimit.rlim_cur;
}
}
DBUG_PRINT("exit",("max_file_limit: %u", max_file_limit));
DBUG_RETURN(max_file_limit);
}
#else
static int set_max_open_files(uint max_file_limit)
{
/* We don't know the limit. Return best guess */
return min(max_file_limit, OS_FILE_LIMIT);
}
#endif
/*
Change number of open files
SYNOPSIS:
my_set_max_open_files()
files Number of requested files
RETURN
number of files available for open
*/
uint my_set_max_open_files(uint files)
{
struct st_my_file_info *tmp;
DBUG_ENTER("my_set_max_open_files");
DBUG_PRINT("enter",("files: %u my_file_limit: %u", files, my_file_limit));
files= set_max_open_files(min(files, OS_FILE_LIMIT));
if (files <= MY_NFILE)
DBUG_RETURN(files);
if (!(tmp= (struct st_my_file_info*) my_malloc(sizeof(*tmp) * files,
MYF(MY_WME))))
DBUG_RETURN(MY_NFILE);
/* Copy any initialized files */
memcpy((char*) tmp, (char*) my_file_info,
sizeof(*tmp) * min(my_file_limit, files));
bzero((char*) (tmp + my_file_limit),
max((int) (files- my_file_limit), 0)*sizeof(*tmp));
my_free_open_file_info(); /* Free if already allocated */
my_file_info= tmp;
my_file_limit= files;
DBUG_PRINT("exit",("files: %u", files));
DBUG_RETURN(files);
}
void my_free_open_file_info()
{
DBUG_ENTER("my_free_file_info");
if (my_file_info != my_file_info_default)
{
/* Copy data back for my_print_open_files */
memcpy((char*) my_file_info_default, my_file_info,
sizeof(*my_file_info_default)* MY_NFILE);
my_free((char*) my_file_info, MYF(0));
my_file_info= my_file_info_default;
my_file_limit= MY_NFILE;
}
DBUG_VOID_RETURN;
}