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f56dd32bf7
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.
192 lines
4.6 KiB
C
192 lines
4.6 KiB
C
/* Copyright (C) 2000 MySQL AB, 2008-2009 Sun Microsystems, Inc
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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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#include "mysys_err.h"
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#include <my_dir.h>
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#include <errno.h>
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/*
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Open a file
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SYNOPSIS
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my_open()
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FileName Fully qualified file name
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Flags Read | write
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MyFlags Special flags
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RETURN VALUE
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File descriptor
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*/
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File my_open(const char *FileName, int Flags, myf MyFlags)
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/* Path-name of file */
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/* Read | write .. */
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/* Special flags */
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{
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File fd;
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DBUG_ENTER("my_open");
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DBUG_PRINT("my",("Name: '%s' Flags: %d MyFlags: %d",
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FileName, Flags, MyFlags));
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#if defined(_WIN32)
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fd= my_win_open(FileName, Flags);
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#elif !defined(NO_OPEN_3)
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fd = open(FileName, Flags, my_umask); /* Normal unix */
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#else
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fd = open((char *) FileName, Flags);
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#endif
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DBUG_RETURN(my_register_filename(fd, FileName, FILE_BY_OPEN,
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EE_FILENOTFOUND, MyFlags));
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} /* my_open */
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/*
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Close a file
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SYNOPSIS
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my_close()
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fd File sescriptor
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myf Special Flags
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*/
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int my_close(File fd, myf MyFlags)
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{
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int err;
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DBUG_ENTER("my_close");
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DBUG_PRINT("my",("fd: %d MyFlags: %d",fd, MyFlags));
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mysql_mutex_lock(&THR_LOCK_open);
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#ifndef _WIN32
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do
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{
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err= close(fd);
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} while (err == -1 && errno == EINTR);
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#else
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err= my_win_close(fd);
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#endif
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if (err)
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{
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DBUG_PRINT("error",("Got error %d on close",err));
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my_errno=errno;
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if (MyFlags & (MY_FAE | MY_WME))
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my_error(EE_BADCLOSE, MYF(ME_BELL+ME_WAITTANG),my_filename(fd),errno);
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}
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if ((uint) fd < my_file_limit && my_file_info[fd].type != UNOPEN)
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{
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my_free(my_file_info[fd].name);
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#if defined(THREAD) && !defined(HAVE_PREAD) && !defined(_WIN32)
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mysql_mutex_destroy(&my_file_info[fd].mutex);
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#endif
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my_file_info[fd].type = UNOPEN;
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}
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my_file_opened--;
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mysql_mutex_unlock(&THR_LOCK_open);
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DBUG_RETURN(err);
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} /* my_close */
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/*
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Register file in my_file_info[]
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SYNOPSIS
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my_register_filename()
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fd File number opened, -1 if error on open
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FileName File name
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type_file_type How file was created
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error_message_number Error message number if caller got error (fd == -1)
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MyFlags Flags for my_close()
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RETURN
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-1 error
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# Filenumber
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*/
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File my_register_filename(File fd, const char *FileName, enum file_type
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type_of_file, uint error_message_number, myf MyFlags)
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{
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DBUG_ENTER("my_register_filename");
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if ((int) fd >= MY_FILE_MIN)
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{
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if ((uint) fd >= my_file_limit)
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{
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#if defined(THREAD) && !defined(HAVE_PREAD)
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my_errno= EMFILE;
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#else
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thread_safe_increment(my_file_opened,&THR_LOCK_open);
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DBUG_RETURN(fd); /* safeguard */
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#endif
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}
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else
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{
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mysql_mutex_lock(&THR_LOCK_open);
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if ((my_file_info[fd].name = (char*) my_strdup(FileName,MyFlags)))
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{
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my_file_opened++;
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my_file_total_opened++;
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my_file_info[fd].type = type_of_file;
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#if defined(THREAD) && !defined(HAVE_PREAD) && !defined(_WIN32)
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mysql_mutex_init(key_my_file_info_mutex, &my_file_info[fd].mutex,
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MY_MUTEX_INIT_FAST);
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#endif
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mysql_mutex_unlock(&THR_LOCK_open);
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DBUG_PRINT("exit",("fd: %d",fd));
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DBUG_RETURN(fd);
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}
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mysql_mutex_unlock(&THR_LOCK_open);
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my_errno= ENOMEM;
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}
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(void) my_close(fd, MyFlags);
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}
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else
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my_errno= errno;
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DBUG_PRINT("error",("Got error %d on open", my_errno));
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if (MyFlags & (MY_FFNF | MY_FAE | MY_WME))
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{
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if (my_errno == EMFILE)
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error_message_number= EE_OUT_OF_FILERESOURCES;
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DBUG_PRINT("error",("print err: %d",error_message_number));
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my_error(error_message_number, MYF(ME_BELL+ME_WAITTANG),
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FileName, my_errno);
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}
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DBUG_RETURN(-1);
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}
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#ifdef EXTRA_DEBUG
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void my_print_open_files(void)
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{
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if (my_file_opened | my_stream_opened)
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{
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uint i;
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for (i= 0 ; i < my_file_limit ; i++)
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{
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if (my_file_info[i].type != UNOPEN)
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{
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fprintf(stderr, EE(EE_FILE_NOT_CLOSED), my_file_info[i].name, i);
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fputc('\n', stderr);
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}
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}
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}
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}
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#endif
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