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mariadb/mysys/my_lib.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

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/* Copyright (C) 2000 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 */
/* TODO: check for overun of memory for names. */
/* Convert MSDOS-TIME to standar time_t (still needed?) */
#include "mysys_priv.h"
#include <m_string.h>
#include <my_dir.h> /* Structs used by my_dir,includes sys/types */
#include "mysys_err.h"
#if defined(HAVE_DIRENT_H)
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# if defined(HAVE_SYS_NDIR_H)
# include <sys/ndir.h>
# endif
# if defined(HAVE_SYS_DIR_H)
# include <sys/dir.h>
# endif
# if defined(HAVE_NDIR_H)
# include <ndir.h>
# endif
# if defined(_WIN32)
# ifdef __BORLANDC__
# include <dir.h>
# endif
# endif
#endif
#ifdef VMS
#include <rms.h>
#include <iodef.h>
#include <descrip.h>
#endif
#if defined(THREAD) && defined(HAVE_READDIR_R)
#define READDIR(A,B,C) ((errno=readdir_r(A,B,&C)) != 0 || !C)
#else
#define READDIR(A,B,C) (!(C=readdir(A)))
#endif
/*
We are assuming that directory we are reading is either has less than
100 files and so can be read in one initial chunk or has more than 1000
files and so big increment are suitable.
*/
#define ENTRIES_START_SIZE (8192/sizeof(FILEINFO))
#define ENTRIES_INCREMENT (65536/sizeof(FILEINFO))
#define NAMES_START_SIZE 32768
static int comp_names(struct fileinfo *a,struct fileinfo *b);
/* We need this because program don't know with malloc we used */
void my_dirend(MY_DIR *buffer)
{
DBUG_ENTER("my_dirend");
if (buffer)
{
delete_dynamic((DYNAMIC_ARRAY*)((char*)buffer +
ALIGN_SIZE(sizeof(MY_DIR))));
free_root((MEM_ROOT*)((char*)buffer + ALIGN_SIZE(sizeof(MY_DIR)) +
ALIGN_SIZE(sizeof(DYNAMIC_ARRAY))), MYF(0));
my_free(buffer);
}
DBUG_VOID_RETURN;
} /* my_dirend */
/* Compare in sort of filenames */
static int comp_names(struct fileinfo *a, struct fileinfo *b)
{
return (strcmp(a->name,b->name));
} /* comp_names */
#if !defined(_WIN32)
MY_DIR *my_dir(const char *path, myf MyFlags)
{
char *buffer;
MY_DIR *result= 0;
FILEINFO finfo;
DYNAMIC_ARRAY *dir_entries_storage;
MEM_ROOT *names_storage;
DIR *dirp;
struct dirent *dp;
char tmp_path[FN_REFLEN+1],*tmp_file;
#ifdef THREAD
char dirent_tmp[sizeof(struct dirent)+_POSIX_PATH_MAX+1];
#endif
DBUG_ENTER("my_dir");
DBUG_PRINT("my",("path: '%s' MyFlags: %d",path,MyFlags));
#if defined(THREAD) && !defined(HAVE_READDIR_R)
mysql_mutex_lock(&THR_LOCK_open);
#endif
dirp = opendir(directory_file_name(tmp_path,(char *) path));
#if defined(__amiga__)
if ((dirp->dd_fd) < 0) /* Directory doesn't exists */
goto error;
#endif
if (dirp == NULL ||
! (buffer= my_malloc(ALIGN_SIZE(sizeof(MY_DIR)) +
ALIGN_SIZE(sizeof(DYNAMIC_ARRAY)) +
sizeof(MEM_ROOT), MyFlags)))
goto error;
dir_entries_storage= (DYNAMIC_ARRAY*)(buffer + ALIGN_SIZE(sizeof(MY_DIR)));
names_storage= (MEM_ROOT*)(buffer + ALIGN_SIZE(sizeof(MY_DIR)) +
ALIGN_SIZE(sizeof(DYNAMIC_ARRAY)));
if (my_init_dynamic_array(dir_entries_storage, sizeof(FILEINFO),
ENTRIES_START_SIZE, ENTRIES_INCREMENT))
{
my_free(buffer);
goto error;
}
init_alloc_root(names_storage, NAMES_START_SIZE, NAMES_START_SIZE);
/* MY_DIR structure is allocated and completly initialized at this point */
result= (MY_DIR*)buffer;
tmp_file=strend(tmp_path);
#ifdef THREAD
dp= (struct dirent*) dirent_tmp;
#else
dp=0;
#endif
while (!(READDIR(dirp,(struct dirent*) dirent_tmp,dp)))
{
if (!(finfo.name= strdup_root(names_storage, dp->d_name)))
goto error;
if (MyFlags & MY_WANT_STAT)
{
if (!(finfo.mystat= (MY_STAT*)alloc_root(names_storage,
sizeof(MY_STAT))))
goto error;
bzero(finfo.mystat, sizeof(MY_STAT));
(void) strmov(tmp_file,dp->d_name);
(void) my_stat(tmp_path, finfo.mystat, MyFlags);
if (!(finfo.mystat->st_mode & MY_S_IREAD))
continue;
}
else
finfo.mystat= NULL;
if (push_dynamic(dir_entries_storage, (uchar*)&finfo))
goto error;
}
(void) closedir(dirp);
#if defined(THREAD) && !defined(HAVE_READDIR_R)
mysql_mutex_unlock(&THR_LOCK_open);
#endif
result->dir_entry= (FILEINFO *)dir_entries_storage->buffer;
result->number_off_files= dir_entries_storage->elements;
if (!(MyFlags & MY_DONT_SORT))
my_qsort((void *) result->dir_entry, result->number_off_files,
sizeof(FILEINFO), (qsort_cmp) comp_names);
DBUG_RETURN(result);
error:
#if defined(THREAD) && !defined(HAVE_READDIR_R)
mysql_mutex_unlock(&THR_LOCK_open);
#endif
my_errno=errno;
if (dirp)
(void) closedir(dirp);
my_dirend(result);
if (MyFlags & (MY_FAE | MY_WME))
my_error(EE_DIR,MYF(ME_BELL+ME_WAITTANG),path,my_errno);
DBUG_RETURN((MY_DIR *) NULL);
} /* my_dir */
/*
* Convert from directory name to filename.
* On VMS:
* xyzzy:[mukesh.emacs] => xyzzy:[mukesh]emacs.dir.1
* xyzzy:[mukesh] => xyzzy:[000000]mukesh.dir.1
* On UNIX, it's simple: just make sure there is a terminating /
* Returns pointer to dst;
*/
char * directory_file_name (char * dst, const char *src)
{
#ifndef VMS
/* Process as Unix format: just remove test the final slash. */
char * end;
if (src[0] == 0)
src= (char*) "."; /* Use empty as current */
end=strmov(dst, src);
if (end[-1] != FN_LIBCHAR)
{
end[0]=FN_LIBCHAR; /* Add last '/' */
end[1]='\0';
}
return dst;
#else /* VMS */
long slen;
long rlen;
char * ptr, rptr;
char bracket;
struct FAB fab = cc$rms_fab;
struct NAM nam = cc$rms_nam;
char esa[NAM$C_MAXRSS];
if (! src[0])
src="[.]"; /* Empty is == current dir */
slen = strlen (src) - 1;
if (src[slen] == FN_C_AFTER_DIR || src[slen] == FN_C_AFTER_DIR_2 ||
src[slen] == FN_DEVCHAR)
{
/* VMS style - convert [x.y.z] to [x.y]z, [x] to [000000]x */
fab.fab$l_fna = src;
fab.fab$b_fns = slen + 1;
fab.fab$l_nam = &nam;
fab.fab$l_fop = FAB$M_NAM;
nam.nam$l_esa = esa;
nam.nam$b_ess = sizeof esa;
nam.nam$b_nop |= NAM$M_SYNCHK;
/* We call SYS$PARSE to handle such things as [--] for us. */
if (SYS$PARSE(&fab, 0, 0) == RMS$_NORMAL)
{
slen = nam.nam$b_esl - 1;
if (esa[slen] == ';' && esa[slen - 1] == '.')
slen -= 2;
esa[slen + 1] = '\0';
src = esa;
}
if (src[slen] != FN_C_AFTER_DIR && src[slen] != FN_C_AFTER_DIR_2)
{
/* what about when we have logical_name:???? */
if (src[slen] == FN_DEVCHAR)
{ /* Xlate logical name and see what we get */
(void) strmov(dst,src);
dst[slen] = 0; /* remove colon */
if (!(src = getenv (dst)))
return dst; /* Can't translate */
/* should we jump to the beginning of this procedure?
Good points: allows us to use logical names that xlate
to Unix names,
Bad points: can be a problem if we just translated to a device
name...
For now, I'll punt and always expect VMS names, and hope for
the best! */
slen = strlen (src) - 1;
if (src[slen] != FN_C_AFTER_DIR && src[slen] != FN_C_AFTER_DIR_2)
{ /* no recursion here! */
(void) strmov(dst, src);
return(dst);
}
}
else
{ /* not a directory spec */
(void) strmov(dst, src);
return(dst);
}
}
bracket = src[slen]; /* End char */
if (!(ptr = strchr (src, bracket - 2)))
{ /* no opening bracket */
(void) strmov (dst, src);
return dst;
}
if (!(rptr = strrchr (src, '.')))
rptr = ptr;
slen = rptr - src;
(void) strmake (dst, src, slen);
if (*rptr == '.')
{ /* Put bracket and add */
dst[slen++] = bracket; /* (rptr+1) after this */
}
else
{
/* If we have the top-level of a rooted directory (i.e. xx:[000000]),
then translate the device and recurse. */
if (dst[slen - 1] == ':'
&& dst[slen - 2] != ':' /* skip decnet nodes */
&& strcmp(src + slen, "[000000]") == 0)
{
dst[slen - 1] = '\0';
if ((ptr = getenv (dst))
&& (rlen = strlen (ptr) - 1) > 0
&& (ptr[rlen] == FN_C_AFTER_DIR || ptr[rlen] == FN_C_AFTER_DIR_2)
&& ptr[rlen - 1] == '.')
{
(void) strmov(esa,ptr);
esa[rlen - 1] = FN_C_AFTER_DIR;
esa[rlen] = '\0';
return (directory_file_name (dst, esa));
}
else
dst[slen - 1] = ':';
}
(void) strmov(dst+slen,"[000000]");
slen += 8;
}
(void) strmov(strmov(dst+slen,rptr+1)-1,".DIR.1");
return dst;
}
(void) strmov(dst, src);
if (dst[slen] == '/' && slen > 1)
dst[slen] = 0;
return dst;
#endif /* VMS */
} /* directory_file_name */
#else
/*
*****************************************************************************
** Read long filename using windows rutines
*****************************************************************************
*/
MY_DIR *my_dir(const char *path, myf MyFlags)
{
char *buffer;
MY_DIR *result= 0;
FILEINFO finfo;
DYNAMIC_ARRAY *dir_entries_storage;
MEM_ROOT *names_storage;
#ifdef __BORLANDC__
struct ffblk find;
#else
struct _finddata_t find;
#endif
ushort mode;
char tmp_path[FN_REFLEN],*tmp_file,attrib;
#ifdef _WIN64
__int64 handle;
#else
long handle;
#endif
DBUG_ENTER("my_dir");
DBUG_PRINT("my",("path: '%s' stat: %d MyFlags: %d",path,MyFlags));
/* Put LIB-CHAR as last path-character if not there */
tmp_file=tmp_path;
if (!*path)
*tmp_file++ ='.'; /* From current dir */
tmp_file= strnmov(tmp_file, path, FN_REFLEN-5);
if (tmp_file[-1] == FN_DEVCHAR)
*tmp_file++= '.'; /* From current dev-dir */
if (tmp_file[-1] != FN_LIBCHAR)
*tmp_file++ =FN_LIBCHAR;
tmp_file[0]='*'; /* Windows needs this !??? */
tmp_file[1]='.';
tmp_file[2]='*';
tmp_file[3]='\0';
if (!(buffer= my_malloc(ALIGN_SIZE(sizeof(MY_DIR)) +
ALIGN_SIZE(sizeof(DYNAMIC_ARRAY)) +
sizeof(MEM_ROOT), MyFlags)))
goto error;
dir_entries_storage= (DYNAMIC_ARRAY*)(buffer + ALIGN_SIZE(sizeof(MY_DIR)));
names_storage= (MEM_ROOT*)(buffer + ALIGN_SIZE(sizeof(MY_DIR)) +
ALIGN_SIZE(sizeof(DYNAMIC_ARRAY)));
if (my_init_dynamic_array(dir_entries_storage, sizeof(FILEINFO),
ENTRIES_START_SIZE, ENTRIES_INCREMENT))
{
my_free(buffer);
goto error;
}
init_alloc_root(names_storage, NAMES_START_SIZE, NAMES_START_SIZE);
/* MY_DIR structure is allocated and completly initialized at this point */
result= (MY_DIR*)buffer;
#ifdef __BORLANDC__
if ((handle= findfirst(tmp_path,&find,0)) == -1L)
#else
if ((handle=_findfirst(tmp_path,&find)) == -1L)
#endif
{
DBUG_PRINT("info", ("findfirst returned error, errno: %d", errno));
if (errno != EINVAL)
goto error;
/*
Could not read the directory, no read access.
Probably because by "chmod -r".
continue and return zero files in dir
*/
}
else
{
do
{
#ifdef __BORLANDC__
attrib= find.ff_attrib;
#else
attrib= find.attrib;
/*
Do not show hidden and system files which Windows sometimes create.
Note. Because Borland's findfirst() is called with the third
argument = 0 hidden/system files are excluded from the search.
*/
if (attrib & (_A_HIDDEN | _A_SYSTEM))
continue;
#endif
#ifdef __BORLANDC__
if (!(finfo.name= strdup_root(names_storage, find.ff_name)))
goto error;
#else
if (!(finfo.name= strdup_root(names_storage, find.name)))
goto error;
#endif
if (MyFlags & MY_WANT_STAT)
{
if (!(finfo.mystat= (MY_STAT*)alloc_root(names_storage,
sizeof(MY_STAT))))
goto error;
bzero(finfo.mystat, sizeof(MY_STAT));
#ifdef __BORLANDC__
finfo.mystat->st_size=find.ff_fsize;
#else
finfo.mystat->st_size=find.size;
#endif
mode= MY_S_IREAD;
if (!(attrib & _A_RDONLY))
mode|= MY_S_IWRITE;
if (attrib & _A_SUBDIR)
mode|= MY_S_IFDIR;
finfo.mystat->st_mode= mode;
#ifdef __BORLANDC__
finfo.mystat->st_mtime= ((uint32) find.ff_ftime);
#else
finfo.mystat->st_mtime= ((uint32) find.time_write);
#endif
}
else
finfo.mystat= NULL;
if (push_dynamic(dir_entries_storage, (uchar*)&finfo))
goto error;
}
#ifdef __BORLANDC__
while (findnext(&find) == 0);
#else
while (_findnext(handle,&find) == 0);
_findclose(handle);
#endif
}
result->dir_entry= (FILEINFO *)dir_entries_storage->buffer;
result->number_off_files= dir_entries_storage->elements;
if (!(MyFlags & MY_DONT_SORT))
my_qsort((void *) result->dir_entry, result->number_off_files,
sizeof(FILEINFO), (qsort_cmp) comp_names);
DBUG_PRINT("exit", ("found %d files", result->number_off_files));
DBUG_RETURN(result);
error:
my_errno=errno;
#ifndef __BORLANDC__
if (handle != -1)
_findclose(handle);
#endif
my_dirend(result);
if (MyFlags & MY_FAE+MY_WME)
my_error(EE_DIR,MYF(ME_BELL+ME_WAITTANG),path,errno);
DBUG_RETURN((MY_DIR *) NULL);
} /* my_dir */
#endif /* _WIN32 */
/****************************************************************************
** File status
** Note that MY_STAT is assumed to be same as struct stat
****************************************************************************/
int my_fstat(File Filedes, MY_STAT *stat_area,
myf MyFlags __attribute__((unused)))
{
DBUG_ENTER("my_fstat");
DBUG_PRINT("my",("fd: %d MyFlags: %d", Filedes, MyFlags));
#ifdef _WIN32
DBUG_RETURN(my_win_fstat(Filedes, stat_area));
#else
DBUG_RETURN(fstat(Filedes, (struct stat *) stat_area));
#endif
}
MY_STAT *my_stat(const char *path, MY_STAT *stat_area, myf my_flags)
{
int m_used;
DBUG_ENTER("my_stat");
DBUG_PRINT("my", ("path: '%s' stat_area: 0x%lx MyFlags: %d", path,
(long) stat_area, my_flags));
if ((m_used= (stat_area == NULL)))
if (!(stat_area= (MY_STAT *) my_malloc(sizeof(MY_STAT), my_flags)))
goto error;
#ifndef _WIN32
if (! stat((char *) path, (struct stat *) stat_area) )
DBUG_RETURN(stat_area);
#else
if (! my_win_stat(path, stat_area) )
DBUG_RETURN(stat_area);
#endif
DBUG_PRINT("error",("Got errno: %d from stat", errno));
my_errno= errno;
if (m_used) /* Free if new area */
my_free(stat_area);
error:
if (my_flags & (MY_FAE+MY_WME))
{
my_error(EE_STAT, MYF(ME_BELL+ME_WAITTANG),path,my_errno);
DBUG_RETURN((MY_STAT *) NULL);
}
DBUG_RETURN((MY_STAT *) NULL);
} /* my_stat */
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