#include <u.h>#include <libc.h>#include <auth.h> int_attrfmt(Fmt *fmt){	char *b, buf[4096], *ebuf;	Attr *a; 	ebuf = buf+sizeof buf;	b = buf;	strcpy(buf, " ");	for(a=va_arg(fmt->args, Attr*); a; a=a->next){		if(a->name == nil)			continue;		switch(a->type){		default:			sysfatal("bad attr %d", a->type);		case AttrQuery:			b = seprint(b, ebuf, " %q?", a->name);			break;		case AttrNameval:			b = seprint(b, ebuf, " %q=%q", a->name, a->val);			break;		case AttrDefault:			b = seprint(b, ebuf, " %q:=%q", a->name, a->val);			break;		}	}	return fmtstrcpy(fmt, buf+1);} Attr*_copyattr(Attr *a){	Attr **la, *na; 	na = nil;	la = &na;	for(; a; a=a->next){		*la = _mkattr(a->type, a->name, a->val, nil);		setmalloctag(*la, getcallerpc(&a));		la = &(*la)->next;	}	*la = nil;	return na;} Attr*_delattr(Attr *a, char *name){	Attr *fa;	Attr **la; 	for(la=&a; *la; ){		if(strcmp((*la)->name, name) == 0){			fa = *la;			*la = (*la)->next;			fa->next = nil;			_freeattr(fa);		}else			la=&(*la)->next;	}	return a;} Attr*_findattr(Attr *a, char *n){	for(; a; a=a->next)		if(strcmp(a->name, n) == 0 && a->type != AttrQuery)			return a;	return nil;} void_freeattr(Attr *a){	Attr *anext; 	for(; a; a=anext){		anext = a->next;		free(a->name);		free(a->val);		a->name = (void*)~0;		a->val = (void*)~0;		a->next = (void*)~0;		free(a);	}} Attr*_mkattr(int type, char *name, char *val, Attr *next){	Attr *a; 	a = malloc(sizeof(*a));	if(a==nil)		sysfatal("_mkattr malloc: %r");	a->type = type;	a->name = strdup(name);	a->val = strdup(val);	if(a->name==nil || a->val==nil)		sysfatal("_mkattr malloc: %r");	a->next = next;	setmalloctag(a, getcallerpc(&type));	return a;} static Attr*cleanattr(Attr *a){	Attr *fa;	Attr **la; 	for(la=&a; *la; ){		if((*la)->type==AttrQuery && _findattr(a, (*la)->name)){			fa = *la;			*la = (*la)->next;			fa->next = nil;			_freeattr(fa);		}else			la=&(*la)->next;	}	return a;} Attr*_parseattr(char *s){	char *p, *t, *tok[256];	int i, ntok, type;	Attr *a; 	s = strdup(s);	if(s == nil)		sysfatal("_parseattr strdup: %r"); 	ntok = tokenize(s, tok, nelem(tok));	a = nil;	for(i=ntok-1; i>=0; i--){		t = tok[i];		if(p = strchr(t, '=')){			*p++ = '\0';		//	if(p-2 >= t && p[-2] == ':'){		//		p[-2] = '\0';		//		type = AttrDefault;		//	}else				type = AttrNameval;			a = _mkattr(type, t, p, a);			setmalloctag(a, getcallerpc(&s));		}		else if(t[strlen(t)-1] == '?'){			t[strlen(t)-1] = '\0';			a = _mkattr(AttrQuery, t, "", a);			setmalloctag(a, getcallerpc(&s));		}else{			/* really a syntax error, but better to provide some indication */			a = _mkattr(AttrNameval, t, "", a);			setmalloctag(a, getcallerpc(&s));		}	}	free(s);	return cleanattr(a);} char*_strfindattr(Attr *a, char *n){	a = _findattr(a, n);	if(a == nil)		return nil;	return a->val;}