/* 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; either version 2 of the License, or (at your option) any later version. 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 */ /* * Memory sub-system, written by Bjorn Benson Fixed to use my_sys scheme by Michael Widenius [This posting refers to an article entitled "oops, corrupted memory again!" in net.lang.c. I am posting it here because it is source.] My tool for approaching this problem is to build another level of data abstraction on top of malloc() and free() that implements some checking. This does a number of things for you: - Checks for overruns and underruns on allocated data - Keeps track of where in the program the memory was malloc'ed - Reports on pieces of memory that were not free'ed - Records some statistics such as maximum memory used - Marks newly malloc'ed and newly free'ed memory with special values You can use this scheme to: - Find bugs such as overrun, underrun, etc because you know where a piece of data was malloc'ed and where it was free'ed - Find bugs where memory was not free'ed - Find bugs where newly malloc'ed memory is used without initializing - Find bugs where newly free'ed memory is still used - Determine how much memory your program really uses - and other things To implement my scheme you must have a C compiler that has __LINE__ and __FILE__ macros. If your compiler doesn't have these then (a) buy another: compilers that do are available on UNIX 4.2bsd based systems and the PC, and probably on other machines; or (b) change my scheme somehow. I have recomendations on both these points if you would like them (e-mail please). There are 4 functions in my package: char *NEW( uSize ) Allocate memory of uSize bytes (equivalent to malloc()) char *REA( pPtr, uSize) Allocate memory of uSize bytes, move data and free pPtr. (equivalent to realloc()) FREE( pPtr ) Free memory allocated by NEW (equivalent to free()) TERMINATE(file) End system, report errors and stats on file I personally use two more functions, but have not included them here: char *STRSAVE( sPtr ) Save a copy of the string in dynamic memory char *RENEW( pPtr, uSize ) (equivalent to realloc()) */ #ifndef SAFEMALLOC #define SAFEMALLOC /* Get protos from my_sys */ #endif #include "mysys_priv.h" #include #include "my_static.h" #include "mysys_err.h" ulonglong safemalloc_mem_limit = ~(ulonglong)0; #define pNext tInt._pNext #define pPrev tInt._pPrev #define sFileName tInt._sFileName #define uLineNum tInt._uLineNum #define uDataSize tInt._uDataSize #define lSpecialValue tInt._lSpecialValue #ifndef PEDANTIC_SAFEMALLOC /* Set to 1 after TERMINATE() if we had to fiddle with cNewCount and the linked list of blocks so that _sanity() will not fuss when it is not supposed to */ static int sf_malloc_tampered = 0; #endif /* Static functions prototypes */ static int check_ptr(const char *where, byte *ptr, const char *sFile, uint uLine); static int _checkchunk(struct remember *pRec, const char *sFile, uint uLine); /* Note: both these refer to the NEW'ed data only. They do not include malloc() roundoff or the extra space required by the remember structures. */ /* NEW'ed memory is filled with this value so that references to it will end up being very strange. */ #define ALLOC_VAL (uchar) 0xA5 /* FEEE'ed memory is filled with this value so that references to it will end up being very strange. */ #define FREE_VAL (uchar) 0x8F #define MAGICKEY 0x14235296 /* A magic value for underrun key */ /* Warning: do not change the MAGICEND? values to something with the high bit set. Various C compilers (like the 4.2bsd one) do not do the sign extension right later on in this code and you will get erroneous errors. */ #define MAGICEND0 0x68 /* Magic values for overrun keys */ #define MAGICEND1 0x34 /* " */ #define MAGICEND2 0x7A /* " */ #define MAGICEND3 0x15 /* " */ /* Allocate some memory. */ gptr _mymalloc (uint uSize, const char *sFile, uint uLine, myf MyFlags) { struct remember *pTmp; DBUG_ENTER("_mymalloc"); DBUG_PRINT("enter",("Size: %u",uSize)); if (!sf_malloc_quick) (void) _sanity (sFile, uLine); if (uSize + lCurMemory > safemalloc_mem_limit) pTmp = 0; else { /* Allocate the physical memory */ pTmp = (struct remember *) malloc ( ALIGN_SIZE(sizeof(struct irem)) /* remember data */ + sf_malloc_prehunc + uSize /* size requested */ + 4 /* overrun mark */ + sf_malloc_endhunc ); } /* Check if there isn't anymore memory avaiable */ if (pTmp == NULL) { if (MyFlags & MY_FAE) error_handler_hook=fatal_error_handler_hook; if (MyFlags & (MY_FAE+MY_WME)) { char buff[SC_MAXWIDTH]; my_errno=errno; sprintf(buff,"Out of memory at line %d, '%s'", uLine, sFile); my_message(EE_OUTOFMEMORY,buff,MYF(ME_BELL+ME_WAITTANG)); sprintf(buff,"needed %d byte (%ldk), memory in use: %ld bytes (%ldk)", uSize, (uSize + 1023L) / 1024L, lMaxMemory, (lMaxMemory + 1023L) / 1024L); my_message(EE_OUTOFMEMORY,buff,MYF(ME_BELL+ME_WAITTANG)); } DBUG_PRINT("error",("Out of memory, in use: %ld at line %d, '%s'", lMaxMemory,uLine, sFile)); if (MyFlags & MY_FAE) exit(1); DBUG_RETURN ((gptr) NULL); } /* Fill up the structure */ *((long*) ((char*) &pTmp -> lSpecialValue+sf_malloc_prehunc)) = MAGICKEY; pTmp -> aData[uSize + sf_malloc_prehunc+0] = MAGICEND0; pTmp -> aData[uSize + sf_malloc_prehunc+1] = MAGICEND1; pTmp -> aData[uSize + sf_malloc_prehunc+2] = MAGICEND2; pTmp -> aData[uSize + sf_malloc_prehunc+3] = MAGICEND3; pTmp -> sFileName = (my_string) sFile; pTmp -> uLineNum = uLine; pTmp -> uDataSize = uSize; pTmp -> pPrev = NULL; /* Add this remember structure to the linked list */ pthread_mutex_lock(&THR_LOCK_malloc); if ((pTmp->pNext=pRememberRoot)) { pRememberRoot -> pPrev = pTmp; } pRememberRoot = pTmp; /* Keep the statistics */ lCurMemory += uSize; if (lCurMemory > lMaxMemory) { lMaxMemory = lCurMemory; } cNewCount++; pthread_mutex_unlock(&THR_LOCK_malloc); /* Set the memory to the aribtrary wierd value */ if ((MyFlags & MY_ZEROFILL) || !sf_malloc_quick) bfill(&pTmp -> aData[sf_malloc_prehunc],uSize, (char) (MyFlags & MY_ZEROFILL ? 0 : ALLOC_VAL)); /* Return a pointer to the real data */ DBUG_PRINT("exit",("ptr: %lx",&(pTmp -> aData[sf_malloc_prehunc]))); if (sf_min_adress > &(pTmp -> aData[sf_malloc_prehunc])) sf_min_adress = &(pTmp -> aData[sf_malloc_prehunc]); if (sf_max_adress < &(pTmp -> aData[sf_malloc_prehunc])) sf_max_adress = &(pTmp -> aData[sf_malloc_prehunc]); DBUG_RETURN ((gptr) &(pTmp -> aData[sf_malloc_prehunc])); } /* Allocate some new memory and move old memoryblock there. Free then old memoryblock */ gptr _myrealloc (register gptr pPtr, register uint uSize, const char *sFile, uint uLine, myf MyFlags) { struct remember *pRec; gptr ptr; DBUG_ENTER("_myrealloc"); if (!pPtr && (MyFlags & MY_ALLOW_ZERO_PTR)) DBUG_RETURN(_mymalloc(uSize,sFile,uLine,MyFlags)); if (!sf_malloc_quick) (void) _sanity (sFile, uLine); if (check_ptr("Reallocating",(byte*) pPtr,sFile,uLine)) DBUG_RETURN((gptr) NULL); pRec = (struct remember *) ((char*) pPtr - ALIGN_SIZE(sizeof(struct irem))- sf_malloc_prehunc); if (*((long*) ((char*) &pRec -> lSpecialValue+sf_malloc_prehunc)) != MAGICKEY) { fprintf(stderr, "Error: Reallocating unallocated data at line %d, '%s'\n", uLine, sFile); DBUG_PRINT("safe",("Reallocating unallocated data at line %d, '%s'", uLine, sFile)); (void) fflush(stderr); DBUG_RETURN((gptr) NULL); } if ((ptr=_mymalloc(uSize,sFile,uLine,MyFlags))) /* Allocate new area */ { uSize=min(uSize,pRec-> uDataSize); /* Move as much as possibly */ memcpy((byte*) ptr,pPtr,(size_t) uSize); /* Copy old data */ _myfree(pPtr,sFile,uLine,0); /* Free not needed area */ } else { if (MyFlags & MY_HOLD_ON_ERROR) DBUG_RETURN(pPtr); if (MyFlags & MY_FREE_ON_ERROR) _myfree(pPtr,sFile,uLine,0); } DBUG_RETURN(ptr); } /* _myrealloc */ /* Deallocate some memory. */ void _myfree (gptr pPtr, const char *sFile, uint uLine, myf myflags) { struct remember *pRec; DBUG_ENTER("_myfree"); DBUG_PRINT("enter",("ptr: %lx",pPtr)); if (!sf_malloc_quick) (void) _sanity (sFile, uLine); if ((!pPtr && (myflags & MY_ALLOW_ZERO_PTR)) || check_ptr("Freeing",(byte*) pPtr,sFile,uLine)) DBUG_VOID_RETURN; /* Calculate the address of the remember structure */ pRec = (struct remember *) ((byte*) pPtr- ALIGN_SIZE(sizeof(struct irem))- sf_malloc_prehunc); /* Check to make sure that we have a real remember structure. Note: this test could fail for four reasons: (1) The memory was already free'ed (2) The memory was never new'ed (3) There was an underrun (4) A stray pointer hit this location */ if (*((long*) ((char*) &pRec -> lSpecialValue+sf_malloc_prehunc)) != MAGICKEY) { fprintf(stderr, "Error: Freeing unallocated data at line %d, '%s'\n", uLine, sFile); DBUG_PRINT("safe",("Unallocated data at line %d, '%s'",uLine,sFile)); (void) fflush(stderr); DBUG_VOID_RETURN; } /* Remove this structure from the linked list */ pthread_mutex_lock(&THR_LOCK_malloc); if (pRec -> pPrev) { pRec -> pPrev -> pNext = pRec -> pNext; } else { pRememberRoot = pRec -> pNext; } if (pRec -> pNext) { pRec -> pNext -> pPrev = pRec -> pPrev; } /* Handle the statistics */ lCurMemory -= pRec -> uDataSize; cNewCount--; pthread_mutex_unlock(&THR_LOCK_malloc); #ifndef HAVE_purify /* Mark this data as free'ed */ if (!sf_malloc_quick) bfill(&pRec->aData[sf_malloc_prehunc],pRec->uDataSize,(pchar) FREE_VAL); #endif *((long*) ((char*) &pRec -> lSpecialValue+sf_malloc_prehunc)) = ~MAGICKEY; /* Actually free the memory */ free ((my_string ) pRec); DBUG_VOID_RETURN; } /* Check if we have a wrong pointer */ static int check_ptr(const char *where, byte *ptr, const char *sFile, uint uLine) { if (!ptr) { fprintf(stderr, "Error: %s NULL pointer at line %d, '%s'\n", where,uLine, sFile); DBUG_PRINT("safe",("Null pointer at line %d '%s'", uLine, sFile)); (void) fflush(stderr); return 1; } #ifndef _MSC_VER if ((long) ptr & (ALIGN_SIZE(1)-1)) { fprintf(stderr, "Error: %s wrong aligned pointer at line %d, '%s'\n", where,uLine, sFile); DBUG_PRINT("safe",("Wrong aligned pointer at line %d, '%s'", uLine,sFile)); (void) fflush(stderr); return 1; } #endif if (ptr < sf_min_adress || ptr > sf_max_adress) { fprintf(stderr, "Error: %s pointer out of range at line %d, '%s'\n", where,uLine, sFile); DBUG_PRINT("safe",("Pointer out of range at line %d '%s'", uLine,sFile)); (void) fflush(stderr); return 1; } return 0; } /* TERMINATE(FILE *file) Report on all the memory pieces that have not been free'ed as well as the statistics. */ void TERMINATE (FILE *file) { struct remember *pPtr; DBUG_ENTER("TERMINATE"); pthread_mutex_lock(&THR_LOCK_malloc); /* Report the difference between number of calls to NEW and the number of calls to FREE. >0 means more NEWs than FREEs. <0, etc. */ if (cNewCount) { if (file) { fprintf(file, "Warning: Not freed memory segments: %d\n", cNewCount); (void) fflush(file); } DBUG_PRINT("safe",("cNewCount: %d",cNewCount)); } /* Report on all the memory that was allocated with NEW but not free'ed with FREE. */ if ((pPtr=pRememberRoot)) { if (file) { fprintf(file, "Warning: Memory that was not free'ed (%ld bytes):\n",lCurMemory); (void) fflush(file); } DBUG_PRINT("safe",("Memory that was not free'ed (%ld bytes):",lCurMemory)); while (pPtr) { if (file) { fprintf(file, "\t%6u bytes at 0x%09lx, allocated at line %4u in '%s'", pPtr -> uDataSize, (ulong) &(pPtr -> aData[sf_malloc_prehunc]), pPtr -> uLineNum, pPtr -> sFileName); fprintf(file, "\n"); (void) fflush(file); } DBUG_PRINT("safe", ("%6u bytes at 0x%09lx, allocated at line %4d in '%s'", pPtr -> uDataSize, &(pPtr -> aData[sf_malloc_prehunc]), pPtr -> uLineNum, pPtr -> sFileName)); pPtr = pPtr -> pNext; } } /* Report the memory usage statistics */ if (file) { fprintf(file, "Maximum memory usage: %ld bytes (%ldk)\n", lMaxMemory, (lMaxMemory + 1023L) / 1024L); (void) fflush(file); } DBUG_PRINT("safe",("Maximum memory usage: %ld bytes (%ldk)", lMaxMemory, (lMaxMemory + 1023L) / 1024L)); pthread_mutex_unlock(&THR_LOCK_malloc); DBUG_VOID_RETURN; } /* Returns 0 if chunk is ok */ static int _checkchunk (register struct remember *pRec, const char *sFile, uint uLine) { reg1 uint uSize; reg2 my_string magicp; reg3 int flag=0; /* Check for a possible underrun */ if (*((long*) ((char*) &pRec -> lSpecialValue+sf_malloc_prehunc)) != MAGICKEY) { fprintf(stderr, "Error: Memory allocated at %s:%d was underrun,", pRec -> sFileName, pRec -> uLineNum); fprintf(stderr, " discovered at %s:%d\n", sFile, uLine); (void) fflush(stderr); DBUG_PRINT("safe",("Underrun at %lx, allocated at %s:%d", &(pRec -> aData[sf_malloc_prehunc]), pRec -> sFileName, pRec -> uLineNum)); flag=1; } /* Check for a possible overrun */ uSize = pRec -> uDataSize; magicp = &(pRec -> aData[uSize+sf_malloc_prehunc]); if (*magicp++ != MAGICEND0 || *magicp++ != MAGICEND1 || *magicp++ != MAGICEND2 || *magicp++ != MAGICEND3) { fprintf(stderr, "Error: Memory allocated at %s:%d was overrun,", pRec -> sFileName, pRec -> uLineNum); fprintf(stderr, " discovered at '%s:%d'\n", sFile, uLine); (void) fflush(stderr); DBUG_PRINT("safe",("Overrun at %lx, allocated at %s:%d", &(pRec -> aData[sf_malloc_prehunc]), pRec -> sFileName, pRec -> uLineNum)); flag=1; } return(flag); } /* Returns how many wrong chunks */ int _sanity (const char *sFile, uint uLine) { reg1 struct remember *pTmp; reg2 int flag=0; uint count=0; pthread_mutex_lock(&THR_LOCK_malloc); #ifndef PEDANTIC_SAFEMALLOC if (sf_malloc_tampered && cNewCount < 0) cNewCount=0; #endif count=cNewCount; for (pTmp = pRememberRoot; pTmp != NULL && count-- ; pTmp = pTmp -> pNext) flag+=_checkchunk (pTmp, sFile, uLine); pthread_mutex_unlock(&THR_LOCK_malloc); if (count || pTmp) { const char *format="Error: Safemalloc link list destroyed, discovered at '%s:%d'"; fprintf(stderr, format, sFile, uLine); fputc('\n',stderr); fprintf(stderr, "root=%p,count=%d,pTmp=%p\n", pRememberRoot,count,pTmp); (void) fflush(stderr); DBUG_PRINT("safe",(format, sFile, uLine)); flag=1; } return flag; } /* _sanity */ /* malloc and copy */ gptr _my_memdup(const byte *from, uint length, const char *sFile, uint uLine, myf MyFlags) { gptr ptr; if ((ptr=_mymalloc(length,sFile,uLine,MyFlags)) != 0) memcpy((byte*) ptr, (byte*) from,(size_t) length); return(ptr); } /*_my_memdup */ char *_my_strdup(const char *from, const char *sFile, uint uLine, myf MyFlags) { gptr ptr; uint length=(uint) strlen(from)+1; if ((ptr=_mymalloc(length,sFile,uLine,MyFlags)) != 0) memcpy((byte*) ptr, (byte*) from,(size_t) length); return((char*) ptr); } /* _my_strdup */ char *_my_strdup_with_length(const byte *from, uint length, const char *sFile, uint uLine, myf MyFlags) { gptr ptr; if ((ptr=_mymalloc(length+1,sFile,uLine,MyFlags)) != 0) { memcpy((byte*) ptr, (byte*) from,(size_t) length); ptr[length]=0; } return((char *) ptr); }