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d01b5c392c
Analysis: --------- When the server is out of memory, an error is raised to indicate the same. Handling the error requires more memory to be allocated which fails, hence the error handling loops in a recursion and causes the server to crash. Fix: --- a) Prevents pushing the 'out of memory' error condition to the diagnostic area as it requires memory allocation. GET DIAGNOSTICS, SHOW WARNINGS and SHOW ERRORS statements will not show information about this error. However the 'out of memory' error is returned to the client. b) It sets the ME_FATALERROR flag when 'out of memory' errors are reported (for places where the flag is not already set). This flag prevents activation of SP error handlers which also require memory allocation and therefore are likely to fail.
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
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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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/* Alloc a block of locked memory */
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#include "mysys_priv.h"
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#include "mysys_err.h"
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#include <my_list.h>
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#ifdef HAVE_MLOCK
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#include <sys/mman.h>
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struct st_mem_list
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{
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LIST list;
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uchar *page;
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uint size;
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};
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LIST *mem_list;
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uchar *my_malloc_lock(uint size,myf MyFlags)
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{
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int success;
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uint pagesize=sysconf(_SC_PAGESIZE);
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uchar *ptr;
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struct st_mem_list *element;
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DBUG_ENTER("my_malloc_lock");
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size=((size-1) & ~(pagesize-1))+pagesize;
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if (!(ptr=memalign(pagesize,size)))
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{
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if (MyFlags & (MY_FAE+MY_WME))
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my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG+ME_FATALERROR), size);
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DBUG_RETURN(0);
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}
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success = mlock((uchar*) ptr,size);
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if (success != 0 && geteuid() == 0)
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{
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DBUG_PRINT("warning",("Failed to lock memory. errno %d\n",
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errno));
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fprintf(stderr, "Warning: Failed to lock memory. errno %d\n",
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errno);
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}
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else
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{
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/* Add block in a list for munlock */
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if (!(element=(struct st_mem_list*) my_malloc(sizeof(*element),MyFlags)))
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{
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(void) munlock((uchar*) ptr,size);
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free(ptr);
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DBUG_RETURN(0);
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}
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element->list.data=(uchar*) element;
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element->page=ptr;
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element->size=size;
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mysql_mutex_lock(&THR_LOCK_malloc);
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mem_list=list_add(mem_list,&element->list);
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mysql_mutex_unlock(&THR_LOCK_malloc);
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}
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DBUG_RETURN(ptr);
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}
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void my_free_lock(uchar *ptr)
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{
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LIST *list;
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struct st_mem_list *element=0;
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mysql_mutex_lock(&THR_LOCK_malloc);
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for (list=mem_list ; list ; list=list->next)
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{
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element=(struct st_mem_list*) list->data;
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if (ptr == element->page)
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{ /* Found locked mem */
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(void) munlock((uchar*) ptr,element->size);
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mem_list=list_delete(mem_list,list);
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break;
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}
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}
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mysql_mutex_unlock(&THR_LOCK_malloc);
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my_free(element);
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free(ptr); /* Free even if not locked */
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}
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#endif /* HAVE_MLOCK */
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