vmdebug.c   [plain text]

#include	"vmhdr.h"

/*	Method to help with debugging. This does rigorous checks on
**	addresses and arena integrity.
**
**	Written by Kiem-Phong Vo, kpv@research.att.com, 01/16/94.
*/

/* structure to keep track of file names */
typedef struct _dbfile_s	Dbfile_t;
struct _dbfile_s
{	Dbfile_t*	next;
	char		file[1];
};
static Dbfile_t*	Dbfile;
	
/* global watch list */
#define S_WATCH	32
static int	Dbnwatch;
static Void_t*	Dbwatch[S_WATCH];

/* types of warnings reported by dbwarn() */
#define	DB_CHECK	0
#define DB_ALLOC	1
#define DB_FREE		2
#define DB_RESIZE	3
#define DB_WATCH	4
#define DB_RESIZED	5

static int Dbinit = 0;
#define DBINIT()	(Dbinit ? 0 : (dbinit(), Dbinit=1) )
static void dbinit()
{	int	fd;	
	if((fd = vmtrace(-1)) >= 0)
		vmtrace(fd);
}

/* just an entry point to make it easy to set break point */
#if __STD_C
static void vmdbwarn(Vmalloc_t* vm, char* mesg, int n)
#else
static void vmdbwarn(vm, mesg, n)
Vmalloc_t*	vm;
char*		mesg;
int		n;
#endif
{
	reg Vmdata_t*	vd = vm->data;

	write(2,mesg,n);
	if(vd->mode&VM_DBABORT)
		abort();
}

/* issue a warning of some type */
#if __STD_C
static void dbwarn(Vmalloc_t* vm, Void_t* data, int where, char* file, int line, int type)
#else
static void dbwarn(vm, data, where, file, line, type)
Vmalloc_t*	vm;	/* region holding the block	*/
Void_t*		data;	/* data block			*/
int		where;	/* byte that was corrupted	*/
char*		file;	/* file where call originates	*/
int		line;	/* line number of call		*/
int		type;	/* operation being done		*/
#endif
{
	char	buf[1024], *bufp, *endbuf, *s;
#define SLOP	64	/* enough for a message and an int */

	DBINIT();

	bufp = buf;
	endbuf = buf + sizeof(buf);

	if(type == DB_ALLOC)
		bufp = (*_Vmstrcpy)(bufp, "alloc error", ':');
	else if(type == DB_FREE)
		bufp = (*_Vmstrcpy)(bufp, "free error", ':');
	else if(type == DB_RESIZE)
		bufp = (*_Vmstrcpy)(bufp, "resize error", ':');
	else if(type == DB_CHECK)
		bufp = (*_Vmstrcpy)(bufp, "corrupted data", ':');
	else if(type == DB_WATCH)
		bufp = (*_Vmstrcpy)(bufp, "alert", ':');

	/* region info */
	bufp = (*_Vmstrcpy)(bufp, "region", '=');
	bufp = (*_Vmstrcpy)(bufp, (*_Vmitoa)(VLONG(vm), 0), ':');

	if(data)
	{	bufp = (*_Vmstrcpy)(bufp,"block",'=');
		bufp = (*_Vmstrcpy)(bufp,(*_Vmitoa)(VLONG(data),0),':');
	}

	if(!data)
	{	if(where == DB_ALLOC)
			bufp = (*_Vmstrcpy)(bufp, "can't get memory", ':');
		else	bufp = (*_Vmstrcpy)(bufp, "region is locked", ':');
	}
	else if(type == DB_FREE || type == DB_RESIZE)
	{	if(where == 0)
			bufp = (*_Vmstrcpy)(bufp, "unallocated block", ':');
		else	bufp = (*_Vmstrcpy)(bufp, "already freed", ':');
	}
	else if(type == DB_WATCH)
	{	bufp = (*_Vmstrcpy)(bufp, "size", '=');
		bufp = (*_Vmstrcpy)(bufp, (*_Vmitoa)(DBSIZE(data),-1), ':');
		if(where == DB_ALLOC)
			bufp = (*_Vmstrcpy)(bufp,"just allocated", ':');
		else if(where == DB_FREE)
			bufp = (*_Vmstrcpy)(bufp,"being freed", ':');
		else if(where == DB_RESIZE)
			bufp = (*_Vmstrcpy)(bufp,"being resized", ':');
		else if(where == DB_RESIZED)
			bufp = (*_Vmstrcpy)(bufp,"just resized", ':');
	}
	else if(type == DB_CHECK)
	{	bufp = (*_Vmstrcpy)(bufp, "bad byte at", '=');
		bufp = (*_Vmstrcpy)(bufp, (*_Vmitoa)(VLONG(where),-1), ':');
		if((s = DBFILE(data)) && (bufp + strlen(s) + SLOP) < endbuf)
		{	bufp = (*_Vmstrcpy)(bufp,"allocated at", '=');
			bufp = (*_Vmstrcpy)(bufp, s, ',');
			bufp = (*_Vmstrcpy)(bufp,(*_Vmitoa)(VLONG(DBLINE(data)),-1),':');
		}
	}

	/* location where offending call originates from */
	if(file && file[0] && line > 0 && (bufp + strlen(file) + SLOP) < endbuf)
	{	bufp = (*_Vmstrcpy)(bufp, "detected at", '=');
		bufp = (*_Vmstrcpy)(bufp, file, ',');
		bufp = (*_Vmstrcpy)(bufp, (*_Vmitoa)(VLONG(line),-1), ':');
	}

	*bufp++ = '\n';
	*bufp = '\0';

	vmdbwarn(vm,buf,(bufp-buf));
}

/* check for watched address and issue warnings */
#if __STD_C
static void dbwatch(Vmalloc_t* vm, Void_t* data, char* file, int line, int type)
#else
static void dbwatch(vm, data, file, line, type)
Vmalloc_t*	vm;
Void_t*		data;
char*		file;
int		line;
int		type;
#endif
{
	reg int		n;

	for(n = Dbnwatch; n >= 0; --n)
	{	if(Dbwatch[n] == data)
		{	dbwarn(vm,data,type,file,line,DB_WATCH);
			return;
		}
	}
}

/* record information about the block */
#if __STD_C
static void dbsetinfo(Vmuchar_t* data, size_t size, char* file, int line)
#else
static void dbsetinfo(data, size, file, line)
Vmuchar_t*		data;	/* real address not the one from Vmbest	*/
size_t		size;	/* the actual requested size		*/
char*		file;	/* file where the request came from	*/
int		line;	/* and line number			*/
#endif
{
	reg Vmuchar_t	*begp, *endp;
	reg Dbfile_t	*last, *db;

	DBINIT();

	/* find the file structure */
	if(!file || !file[0])
		db = NIL(Dbfile_t*);
	else
	{	for(last = NIL(Dbfile_t*), db = Dbfile; db; last = db, db = db->next)
			if(strcmp(db->file,file) == 0)
				break;
		if(!db)
		{	db = (Dbfile_t*)vmalloc(Vmheap,sizeof(Dbfile_t)+strlen(file));
			if(db)
			{	(*_Vmstrcpy)(db->file,file,0);
				db->next = Dbfile;
				Dbfile = db->next;
			}
		}
		else if(last) /* move-to-front heuristic */
		{	last->next = db->next;
			db->next = Dbfile;
			Dbfile = db->next;
		}
	}

	DBSETFL(data,(db ? db->file : NIL(char*)),line);
	DBSIZE(data) = size;
	DBSEG(data)  = SEG(DBBLOCK(data));

	DBHEAD(data,begp,endp);
	while(begp < endp)
		*begp++ = DB_MAGIC;
	DBTAIL(data,begp,endp);
	while(begp < endp)
		*begp++ = DB_MAGIC;
}

/* Check to see if an address is in some data block of a region.
** This returns -(offset+1) if block is already freed, +(offset+1)
** if block is live, 0 if no match.
*/
#if __STD_C
static long dbaddr(Vmalloc_t* vm, Void_t* addr)
#else
static long dbaddr(vm, addr)
Vmalloc_t*	vm;
Void_t*		addr;
#endif
{
	reg Block_t	*b, *endb;
	reg Seg_t*	seg;
	reg Vmuchar_t*	data;
	reg long	offset = -1L;
	reg Vmdata_t*	vd = vm->data;
	reg int		local;

	GETLOCAL(vd,local);
	if(ISLOCK(vd,local) || !addr)
		return -1L;
	SETLOCK(vd,local);

	for(seg = vd->seg; seg; seg = seg->next)
	{	b = SEGBLOCK(seg);
		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
		if((Vmuchar_t*)addr > (Vmuchar_t*)b &&
		   (Vmuchar_t*)addr < (Vmuchar_t*)endb)
			break;
	}
	if(!seg)
		goto done;

	if(local)	/* must be vmfree or vmresize checking address */
	{	if(DBSEG(addr) == seg)
		{	b = DBBLOCK(addr);
			if(ISBUSY(SIZE(b)) && !ISJUNK(SIZE(b)) )
				offset = 0;
			else	offset = -2L;
		}
		goto done;
	}

	while(b < endb)
	{	data = (Vmuchar_t*)DATA(b);
		if((Vmuchar_t*)addr >= data && (Vmuchar_t*)addr < data+SIZE(b))
		{	if(ISBUSY(SIZE(b)) && !ISJUNK(SIZE(b)) )
			{	data = DB2DEBUG(data);
				if((Vmuchar_t*)addr >= data &&
				   (Vmuchar_t*)addr < data+DBSIZE(data))
					offset =  (Vmuchar_t*)addr - data;
			}
			goto done;
		}

		b = (Block_t*)((Vmuchar_t*)DATA(b) + (SIZE(b)&~BITS) );
	}

done:
	CLRLOCK(vd,local);
	return offset;
}


#if __STD_C
static long dbsize(Vmalloc_t* vm, Void_t* addr)
#else
static long dbsize(vm, addr)
Vmalloc_t*	vm;
Void_t*		addr;
#endif
{
	reg Block_t	*b, *endb;
	reg Seg_t*	seg;
	reg long	size;
	reg Vmdata_t*	vd = vm->data;

	if(ISLOCK(vd,0))
		return -1L;
	SETLOCK(vd,0);

	size = -1L;
	for(seg = vd->seg; seg; seg = seg->next)
	{	b = SEGBLOCK(seg);
		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
		if((Vmuchar_t*)addr <= (Vmuchar_t*)b ||
		   (Vmuchar_t*)addr >= (Vmuchar_t*)endb)
			continue;
		while(b < endb)
		{	if(addr == (Void_t*)DB2DEBUG(DATA(b)))
			{	if(ISBUSY(SIZE(b)) && !ISJUNK(SIZE(b)) )
					size = (long)DBSIZE(addr);
				goto done;
			}

			b = (Block_t*)((Vmuchar_t*)DATA(b) + (SIZE(b)&~BITS) );
		}
	}
done:
	CLRLOCK(vd,0);
	return size;
}

#if __STD_C
static Void_t* dballoc(Vmalloc_t* vm, size_t size)
#else
static Void_t* dballoc(vm, size)
Vmalloc_t*	vm;
size_t		size;
#endif
{
	reg size_t	s;
	reg Vmuchar_t*	data;
	reg char*	file;
	reg int		line;
	reg Vmdata_t*	vd = vm->data;

	VMFILELINE(vm,file,line);

	if(ISLOCK(vd,0) )
	{	dbwarn(vm,NIL(Vmuchar_t*),0,file,line,DB_ALLOC);
		return NIL(Void_t*);
	}
	SETLOCK(vd,0);

	if(vd->mode&VM_DBCHECK)
		vmdbcheck(vm);

	s = ROUND(size,ALIGN) + DB_EXTRA;
	if(s < sizeof(Body_t))	/* no tiny blocks during Vmdebug */
		s = sizeof(Body_t);

	if(!(data = (Vmuchar_t*)KPVALLOC(vm,s,(*(Vmbest->allocf))) ) )
	{	dbwarn(vm,NIL(Vmuchar_t*),DB_ALLOC,file,line,DB_ALLOC);
		goto done;
	}

	data = DB2DEBUG(data);
	dbsetinfo(data,size,file,line);

	if((vd->mode&VM_TRACE) && _Vmtrace)
	{	vm->file = file; vm->line = line;
		(*_Vmtrace)(vm,NIL(Vmuchar_t*),data,size,0);
	}

	if(Dbnwatch > 0 )
		dbwatch(vm,data,file,line,DB_ALLOC);

done:
	CLRLOCK(vd,0);
	return (Void_t*)data;
}


#if __STD_C
static int dbfree(Vmalloc_t* vm, Void_t* data )
#else
static int dbfree(vm, data )
Vmalloc_t*	vm;
Void_t*		data;
#endif
{
	char*		file;
	int		line;
	reg long	offset;
	reg int		*ip, *endip;
	reg Vmdata_t*	vd = vm->data;

	VMFILELINE(vm,file,line);

	if(!data)
		return 0;

	if(ISLOCK(vd,0) )
	{	dbwarn(vm,NIL(Vmuchar_t*),0,file,line,DB_FREE);
		return -1;
	}
	SETLOCK(vd,0);

	if(vd->mode&VM_DBCHECK)
		vmdbcheck(vm);

	if((offset = KPVADDR(vm,data,dbaddr)) != 0)
	{	if(vm->disc->exceptf)
			(void)(*vm->disc->exceptf)(vm,VM_BADADDR,data,vm->disc);
		dbwarn(vm,(Vmuchar_t*)data,offset == -1L ? 0 : 1,file,line,DB_FREE);
		CLRLOCK(vd,0);
		return -1;
	}

	if(Dbnwatch > 0)
		dbwatch(vm,data,file,line,DB_FREE);

	if((vd->mode&VM_TRACE) && _Vmtrace)
	{	vm->file = file; vm->line = line;
		(*_Vmtrace)(vm,(Vmuchar_t*)data,NIL(Vmuchar_t*),DBSIZE(data),0);
	}

	/* clear free space */
	ip = (int*)data;
	endip = ip + (DBSIZE(data)+sizeof(int)-1)/sizeof(int);
	while(ip < endip)
		*ip++ = 0;

	CLRLOCK(vd,0);
	return (*(Vmbest->freef))(vm,(Void_t*)DB2BEST(data));
}

/*	Resizing an existing block */
#if __STD_C
static Void_t* dbresize(Vmalloc_t* vm, Void_t* addr, reg size_t size, int type)
#else
static Void_t* dbresize(vm,addr,size,type)
Vmalloc_t*	vm;		/* region allocating from	*/
Void_t*		addr;		/* old block of data		*/
reg size_t	size;		/* new size			*/
int		type;		/* !=0 for movable, >0 for copy	*/
#endif
{
	reg Vmuchar_t*	data;
	reg size_t	s, oldsize;
	reg long	offset;
	char		*file, *oldfile;
	int		line, oldline;
	reg Vmdata_t*	vd = vm->data;

	if(!addr)
	{	oldsize = 0;
		data = (Vmuchar_t*)dballoc(vm,size);
		goto done;
	}
	if(size == 0)
	{	(void)dbfree(vm,addr);
		return NIL(Void_t*);
	}

	VMFILELINE(vm,file,line);

	if(ISLOCK(vd,0) )
	{	dbwarn(vm,NIL(Vmuchar_t*),0,file,line,DB_RESIZE);
		return NIL(Void_t*);
	}
	SETLOCK(vd,0);

	if(vd->mode&VM_DBCHECK)
		vmdbcheck(vm);

	if((offset = KPVADDR(vm,addr,dbaddr)) != 0)
	{	if(vm->disc->exceptf)
			(void)(*vm->disc->exceptf)(vm,VM_BADADDR,addr,vm->disc);
		dbwarn(vm,(Vmuchar_t*)addr,offset == -1L ? 0 : 1,file,line,DB_RESIZE);
		CLRLOCK(vd,0);
		return NIL(Void_t*);
	}

	if(Dbnwatch > 0)
		dbwatch(vm,addr,file,line,DB_RESIZE);

	/* Vmbest data block */
	data = DB2BEST(addr);
	oldsize = DBSIZE(addr);
	oldfile = DBFILE(addr);
	oldline = DBLINE(addr);

	/* do the resize */
	s = ROUND(size,ALIGN) + DB_EXTRA;
	if(s < sizeof(Body_t))
		s = sizeof(Body_t);
	data = (Vmuchar_t*)KPVRESIZE(vm,(Void_t*)data,s,
				 (type&~VM_RSZERO),(*(Vmbest->resizef)) );
	if(!data) /* failed, reset data for old block */
	{	dbwarn(vm,NIL(Vmuchar_t*),DB_ALLOC,file,line,DB_RESIZE);
		dbsetinfo((Vmuchar_t*)addr,oldsize,oldfile,oldline);
	}
	else
	{	data = DB2DEBUG(data);
		dbsetinfo(data,size,file,line);

		if((vd->mode&VM_TRACE) && _Vmtrace)
		{	vm->file = file; vm->line = line;
			(*_Vmtrace)(vm,(Vmuchar_t*)addr,data,size,0);
		}
		if(Dbnwatch > 0)
			dbwatch(vm,data,file,line,DB_RESIZED);
	}

	CLRLOCK(vd,0);

done:	if(data && (type&VM_RSZERO) && size > oldsize)
	{	reg Vmuchar_t *d = data+oldsize, *ed = data+size;
		do { *d++ = 0; } while(d < ed);
	}
	return (Void_t*)data;
}

/* compact any residual free space */
#if __STD_C
static int dbcompact(Vmalloc_t* vm)
#else
static int dbcompact(vm)
Vmalloc_t*	vm;
#endif
{
	return (*(Vmbest->compactf))(vm);
}

/* check for memory overwrites over all live blocks */
#if __STD_C
int vmdbcheck(Vmalloc_t* vm)
#else
int vmdbcheck(vm)
Vmalloc_t*	vm;
#endif
{
	reg Block_t	*b, *endb;
	reg Seg_t*	seg;
	int		rv;
	reg Vmdata_t*	vd = vm->data;

	if(!(vd->mode&VM_MTDEBUG) )
		return -1;

	rv = 0;
	for(seg = vd->seg; seg; seg = seg->next)
	{	b = SEGBLOCK(seg);
		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
		while(b < endb)
		{	reg Vmuchar_t	*data, *begp, *endp;

			if(ISJUNK(SIZE(b)) || !ISBUSY(SIZE(b)))
				goto next;

			data = DB2DEBUG(DATA(b));
			if(DBISBAD(data))	/* seen this before */
			{	rv += 1;
				goto next;
			}

			DBHEAD(data,begp,endp);
			for(; begp < endp; ++begp)
				if(*begp != DB_MAGIC)
					goto set_bad;

			DBTAIL(data,begp,endp);
			for(; begp < endp; ++begp)
			{	if(*begp == DB_MAGIC)
					continue;
			set_bad:
				dbwarn(vm,data,begp-data,NIL(char*),0,DB_CHECK);
				DBSETBAD(data);
				rv += 1;
				goto next;
			}

		next:	b = (Block_t*)((Vmuchar_t*)DATA(b) + (SIZE(b)&~BITS));
		}
	}

	return rv;
}

/* set/delete an address to watch */
#if __STD_C
Void_t* vmdbwatch(Void_t* addr)
#else
Void_t* vmdbwatch(addr)
Void_t*		addr;	/* address to insert			*/
#endif
{
	reg int		n;
	reg Void_t*	out;

	out = NIL(Void_t*);
	if(!addr)
		Dbnwatch = 0;
	else
	{	for(n = Dbnwatch - 1; n >= 0; --n)
			if(Dbwatch[n] == addr)
				break;
		if(n < 0)	/* insert */
		{	if(Dbnwatch == S_WATCH)	
			{	/* delete left-most */
				out = Dbwatch[0];
				Dbnwatch -= 1;
				for(n = 0; n < Dbnwatch; ++n)
					Dbwatch[n] = Dbwatch[n+1];
			}
			Dbwatch[Dbnwatch] = addr;
			Dbnwatch += 1;
		}
	}
	return out;
}

#if __STD_C
static Void_t* dbalign(Vmalloc_t* vm, size_t size, size_t align)
#else
static Void_t* dbalign(vm, size, align)
Vmalloc_t*	vm;
size_t		size;
size_t		align;
#endif
{
	reg Vmuchar_t	*data;
	reg size_t	s;
	reg char*	file;
	reg int		line;
	reg Vmdata_t*	vd = vm->data;

	VMFILELINE(vm,file,line);

	if(size <= 0 || align <= 0)
		return NIL(Void_t*);

	if(!(vd->mode&VM_TRUST) )
	{	if(ISLOCK(vd,0) )
			return NIL(Void_t*);
		SETLOCK(vd,0);
	}

	if((s = ROUND(size,ALIGN) + DB_EXTRA) < sizeof(Body_t))
		s = sizeof(Body_t);

	if(!(data = (Vmuchar_t*)KPVALIGN(vm,s,align,(*(Vmbest->alignf)))) )
		goto done;

	data += DB_HEAD;
	dbsetinfo(data,size,file,line);

	if((vd->mode&VM_TRACE) && _Vmtrace)
	{	vm->file = file; vm->line = line;
		(*_Vmtrace)(vm,NIL(Vmuchar_t*),data,size,align);
	}

done:
	CLRLOCK(vd,0);
	return (Void_t*)data;
}

static Vmethod_t _Vmdebug =
{
	dballoc,
	dbresize,
	dbfree,
	dbaddr,
	dbsize,
	dbcompact,
	dbalign,
	VM_MTDEBUG
};

__DEFINE__(Vmethod_t*,Vmdebug,&_Vmdebug);