mariadb/sql/derror.cc
Davi Arnaut f56dd32bf7 Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.

client/mysqldump.c:
  Pass my_free directly as its signature is compatible with the
  callback type -- which wasn't the case for free_table_ent.
2010-07-08 18:20:08 -03:00

229 lines
6.6 KiB
C++

/* Copyright (C) 2000-2005 MySQL AB, 2008-2009 Sun Microsystems, Inc
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 */
/**
@file
@brief
Read language depeneded messagefile
*/
#include "sql_priv.h"
#include "unireg.h"
#include "derror.h"
#include "mysys_err.h"
#include "mysqld.h" // lc_messages_dir
#include "derror.h" // read_texts
#include "sql_class.h" // THD
static void init_myfunc_errs(void);
C_MODE_START
static const char **get_server_errmsgs()
{
return CURRENT_THD_ERRMSGS;
}
C_MODE_END
/**
Read messages from errorfile.
This function can be called multiple times to reload the messages.
If it fails to load the messages, it will fail softly by initializing
the errmesg pointer to an array of empty strings or by keeping the
old array if it exists.
@retval
FALSE OK
@retval
TRUE Error
*/
bool init_errmessage(void)
{
const char **errmsgs, **ptr;
DBUG_ENTER("init_errmessage");
/*
Get a pointer to the old error messages pointer array.
read_texts() tries to free it.
*/
errmsgs= my_error_unregister(ER_ERROR_FIRST, ER_ERROR_LAST);
/* Read messages from file. */
if (read_texts(ERRMSG_FILE, my_default_lc_messages->errmsgs->language,
&errmsgs, ER_ERROR_LAST - ER_ERROR_FIRST + 1) &&
!errmsgs)
{
if (!(errmsgs= (const char**) my_malloc((ER_ERROR_LAST-ER_ERROR_FIRST+1)*
sizeof(char*), MYF(0))))
DBUG_RETURN(TRUE);
for (ptr= errmsgs; ptr < errmsgs + ER_ERROR_LAST - ER_ERROR_FIRST; ptr++)
*ptr= "";
}
/* Register messages for use with my_error(). */
if (my_error_register(get_server_errmsgs, ER_ERROR_FIRST, ER_ERROR_LAST))
{
my_free(errmsgs);
DBUG_RETURN(TRUE);
}
DEFAULT_ERRMSGS= errmsgs; /* Init global variable */
init_myfunc_errs(); /* Init myfunc messages */
DBUG_RETURN(FALSE);
}
/**
Read text from packed textfile in language-directory.
If we can't read messagefile then it's panic- we can't continue.
*/
bool read_texts(const char *file_name, const char *language,
const char ***point, uint error_messages)
{
register uint i;
uint count,funktpos,textcount;
size_t length;
File file;
char name[FN_REFLEN];
char lang_path[FN_REFLEN];
uchar *buff;
uchar head[32],*pos;
const char *errmsg;
DBUG_ENTER("read_texts");
LINT_INIT(buff);
funktpos=0;
convert_dirname(lang_path, language, NullS);
(void) my_load_path(lang_path, lang_path, lc_messages_dir);
if ((file= mysql_file_open(key_file_ERRMSG,
fn_format(name, file_name, lang_path, "", 4),
O_RDONLY | O_SHARE | O_BINARY,
MYF(0))) < 0)
{
/*
Trying pre-5.4 sematics of the --language parameter.
It included the language-specific part, e.g.:
--language=/path/to/english/
*/
if ((file= mysql_file_open(key_file_ERRMSG,
fn_format(name, file_name, lc_messages_dir, "", 4),
O_RDONLY | O_SHARE | O_BINARY,
MYF(0))) < 0)
goto err;
sql_print_error("An old style --language value with language specific part detected: %s", lc_messages_dir);
sql_print_error("Use --lc-messages-dir without language specific part instead.");
}
funktpos=1;
if (mysql_file_read(file, (uchar*) head, 32, MYF(MY_NABP)))
goto err;
if (head[0] != (uchar) 254 || head[1] != (uchar) 254 ||
head[2] != 2 || head[3] != 1)
goto err; /* purecov: inspected */
textcount=head[4];
error_message_charset_info= system_charset_info;
length=uint2korr(head+6); count=uint2korr(head+8);
if (count < error_messages)
{
sql_print_error("\
Error message file '%s' had only %d error messages,\n\
but it should contain at least %d error messages.\n\
Check that the above file is the right version for this program!",
name,count,error_messages);
(void) mysql_file_close(file, MYF(MY_WME));
DBUG_RETURN(1);
}
/* Free old language */
my_free(*point);
if (!(*point= (const char**)
my_malloc((size_t) (length+count*sizeof(char*)),MYF(0))))
{
funktpos=2; /* purecov: inspected */
goto err; /* purecov: inspected */
}
buff= (uchar*) (*point + count);
if (mysql_file_read(file, buff, (size_t) count*2, MYF(MY_NABP)))
goto err;
for (i=0, pos= buff ; i< count ; i++)
{
(*point)[i]= (char*) buff+uint2korr(pos);
pos+=2;
}
if (mysql_file_read(file, buff, length, MYF(MY_NABP)))
goto err;
for (i=1 ; i < textcount ; i++)
{
point[i]= *point +uint2korr(head+10+i+i);
}
(void) mysql_file_close(file, MYF(0));
DBUG_RETURN(0);
err:
switch (funktpos) {
case 2:
errmsg= "Not enough memory for messagefile '%s'";
break;
case 1:
errmsg= "Can't read from messagefile '%s'";
break;
default:
errmsg= "Can't find messagefile '%s'";
break;
}
sql_print_error(errmsg, name);
if (file != FERR)
(void) mysql_file_close(file, MYF(MY_WME));
DBUG_RETURN(1);
} /* read_texts */
/**
Initiates error-messages used by my_func-library.
*/
static void init_myfunc_errs()
{
init_glob_errs(); /* Initiate english errors */
if (!(specialflag & SPECIAL_ENGLISH))
{
EE(EE_FILENOTFOUND) = ER(ER_FILE_NOT_FOUND);
EE(EE_CANTCREATEFILE) = ER(ER_CANT_CREATE_FILE);
EE(EE_READ) = ER(ER_ERROR_ON_READ);
EE(EE_WRITE) = ER(ER_ERROR_ON_WRITE);
EE(EE_BADCLOSE) = ER(ER_ERROR_ON_CLOSE);
EE(EE_OUTOFMEMORY) = ER(ER_OUTOFMEMORY);
EE(EE_DELETE) = ER(ER_CANT_DELETE_FILE);
EE(EE_LINK) = ER(ER_ERROR_ON_RENAME);
EE(EE_EOFERR) = ER(ER_UNEXPECTED_EOF);
EE(EE_CANTLOCK) = ER(ER_CANT_LOCK);
EE(EE_DIR) = ER(ER_CANT_READ_DIR);
EE(EE_STAT) = ER(ER_CANT_GET_STAT);
EE(EE_GETWD) = ER(ER_CANT_GET_WD);
EE(EE_SETWD) = ER(ER_CANT_SET_WD);
EE(EE_DISK_FULL) = ER(ER_DISK_FULL);
}
}