mariadb/extra/my_print_defaults.c
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

207 lines
6.6 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 */
/*
** print_default.c:
** Print all parameters in a default file that will be given to some program.
**
** Written by Monty
*/
#include <my_global.h>
#include <my_sys.h>
#include <m_string.h>
#include <my_getopt.h>
const char *config_file="my"; /* Default config file */
uint verbose= 0, opt_defaults_file_used= 0;
const char *default_dbug_option="d:t:o,/tmp/my_print_defaults.trace";
static struct my_option my_long_options[] =
{
/*
NB: --config-file is troublesome, because get_defaults_options() doesn't
know about it, but we pretend --config-file is like --defaults-file. In
fact they behave differently: see the comments at the top of
mysys/default.c for how --defaults-file should behave.
This --config-file option behaves as:
- If it has a directory name part (absolute or relative), then only this
file is read; no error is given if the file doesn't exist
- If the file has no directory name part, the standard locations are
searched for a file of this name (and standard filename extensions are
added if the file has no extension)
*/
{"config-file", 'c', "Deprecated, please use --defaults-file instead. "
"Name of config file to read; if no extension is given, default "
"extension (e.g., .ini or .cnf) will be added",
&config_file, &config_file, 0, GET_STR, REQUIRED_ARG,
0, 0, 0, 0, 0, 0},
#ifdef DBUG_OFF
{"debug", '#', "This is a non-debug version. Catch this and exit",
0,0, 0, GET_DISABLED, OPT_ARG, 0, 0, 0, 0, 0, 0},
#else
{"debug", '#', "Output debug log", &default_dbug_option,
&default_dbug_option, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
#endif
{"defaults-file", 'c', "Like --config-file, except: if first option, "
"then read this file only, do not read global or per-user config "
"files; should be the first option",
&config_file, &config_file, 0, GET_STR, REQUIRED_ARG,
0, 0, 0, 0, 0, 0},
{"defaults-extra-file", 'e',
"Read this file after the global config file and before the config "
"file in the users home directory; should be the first option",
&my_defaults_extra_file, &my_defaults_extra_file, 0,
GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
{"defaults-group-suffix", 'g',
"In addition to the given groups, read also groups with this suffix",
&my_defaults_group_suffix, &my_defaults_group_suffix,
0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
{"extra-file", 'e',
"Deprecated. Synonym for --defaults-extra-file.",
&my_defaults_extra_file,
&my_defaults_extra_file, 0, GET_STR,
REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
{"no-defaults", 'n', "Return an empty string (useful for scripts).",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"help", '?', "Display this help message and exit.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"verbose", 'v', "Increase the output level",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"version", 'V', "Output version information and exit.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
};
#include <help_start.h>
static void usage(my_bool version)
{
printf("%s Ver 1.6 for %s at %s\n",my_progname,SYSTEM_TYPE,
MACHINE_TYPE);
if (version)
return;
puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license\n");
puts("Prints all arguments that is give to some program using the default files");
printf("Usage: %s [OPTIONS] groups\n", my_progname);
my_print_help(my_long_options);
my_print_default_files(config_file);
my_print_variables(my_long_options);
printf("\nExample usage:\n%s --defaults-file=example.cnf client mysql\n", my_progname);
}
#include <help_end.h>
static my_bool
get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
char *argument __attribute__((unused)))
{
switch (optid) {
case 'c':
opt_defaults_file_used= 1;
break;
case 'n':
exit(0);
case 'I':
case '?':
usage(0);
exit(0);
case 'v':
verbose++;
break;
case 'V':
usage(1);
exit(0);
case '#':
DBUG_PUSH(argument ? argument : default_dbug_option);
break;
}
return 0;
}
static int get_options(int *argc,char ***argv)
{
int ho_error;
if ((ho_error=handle_options(argc, argv, my_long_options, get_one_option)))
exit(ho_error);
if (*argc < 1)
{
usage(0);
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
int count, error, args_used;
char **load_default_groups, *tmp_arguments[6];
char **argument, **arguments, **org_argv;
char *defaults, *extra_defaults, *group_suffix;
MY_INIT(argv[0]);
org_argv= argv;
args_used= get_defaults_options(argc, argv, &defaults, &extra_defaults,
&group_suffix);
/* Copy defaults-xxx arguments & program name */
count=args_used+1;
arguments= tmp_arguments;
memcpy((char*) arguments, (char*) org_argv, count * sizeof(*org_argv));
arguments[count]= 0;
/* Check out the args */
if (!(load_default_groups=(char**) my_malloc((argc+1)*sizeof(char*),
MYF(MY_WME))))
exit(1);
if (get_options(&argc,&argv))
exit(1);
memcpy((char*) load_default_groups, (char*) argv, (argc + 1) * sizeof(*argv));
if ((error= load_defaults(config_file, (const char **) load_default_groups,
&count, &arguments)))
{
if (verbose && opt_defaults_file_used)
{
if (error == 1)
fprintf(stderr, "WARNING: Defaults file '%s' not found!\n",
config_file);
/* This error is not available now. For the future */
if (error == 2)
fprintf(stderr, "WARNING: Defaults file '%s' is not a regular file!\n",
config_file);
}
error= 2;
exit(error);
}
for (argument= arguments+1 ; *argument ; argument++)
if (*argument != args_separator) /* skip arguments separator */
puts(*argument);
my_free(load_default_groups);
free_defaults(arguments);
exit(0);
}