#include <u.h>#include <libc.h>#include <bio.h>#include <ndb.h> /* *  search the database for matches */voidusage(void){	fprint(2, "usage: query attr value [returned attribute]\n");	exits("usage");} voidsearch(Ndb *db, char *attr, char *val, char *rattr){	Ndbs s;	Ndbtuple *t;	Ndbtuple *nt;	char buf[Ndbvlen]; 	if(rattr){		t = ndbgetval(db, &s, attr, val, rattr, buf);		if(t){			print("%s\n", buf);			ndbfree(t);		}		return;	} 	t = ndbsearch(db, &s, attr, val);	while(t){		for(nt = t; nt; nt = nt->entry)			print("%s=%s ", nt->attr, nt->val);		print("\n");		ndbfree(t);		t = ndbsnext(&s, attr, val);	}} voidmain(int argc, char **argv){	char *rattr = 0;	Ndb *db;	char *dbfile = 0;	int reps = 1; 	ARGBEGIN{	case 'f':		dbfile = ARGF();		break;	}ARGEND; 	switch(argc){	case 4:		reps = atoi(argv[3]);		/* fall through */	case 3:		rattr = argv[2];		break;	case 2:		rattr = 0;		break;	default:		usage();	}		db = ndbopen(dbfile);	if(db == 0){		fprint(2, "no db files\n");		exits("no db");	}	while(reps--)		search(db, argv[0], argv[1], rattr);	ndbclose(db); 	exits(0);}