#include <u.h>#include <libc.h>#include <auth.h> int_attrfmt(Fmt *fmt){	Attr *a;	int first = 1; 	for(a=va_arg(fmt->args, Attr*); a != nil; a=a->next){		if(a->name == nil)			continue;		switch(a->type){		default:			continue;		case AttrQuery:			fmtprint(fmt, first+" %q?", a->name);			break;		case AttrNameval:		case AttrDefault:			fmtprint(fmt, first+" %q=%q", a->name, a->val);			break;		}		first = 0;	}	return 0;} 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;	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, '=')) != nil){			*p++ = '\0';			a = _mkattr(AttrNameval, t, p, a);		}else if((p = strchr(t, '\0')-1) >= t && *p == '?'){			*p = '\0';			a = _mkattr(AttrQuery, t, "", a);		}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;}