/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <ctype.h>#include <ndb.h>#include "ndbhf.h" static Ndb*	doopen(char*);static void	hffree(Ndb*); static char *deffile = "/lib/ndb/local"; /* *  the database entry in 'file' indicates the list of files *  that makeup the database.  Open each one and search in *  the same order. */Ndb*ndbopen(char *file){	Ndb *db, *first, *last;	Ndbs s;	Ndbtuple *t, *nt; 	if(file == nil && (file = getenv("NDBFILE")) == nil)		file = deffile;	db = doopen(file);	if(db == 0)		return 0;	first = last = db;	t = ndbsearch(db, &s, "database", "");	Bseek(&db->b, 0, 0);	if(t == 0)		return db;	for(nt = t; nt; nt = nt->entry){		if(strcmp(nt->attr, "file") != 0)			continue;		if(strcmp(nt->val, file) == 0){			/* default file can be reordered in the list */			if(first->next == 0)				continue;			if(strcmp(first->file, file) == 0){				db = first;				first = first->next;				last->next = db;				db->next = 0;				last = db;			}			continue;		}		db = doopen(nt->val);		if(db == 0)			continue;		last->next = db;		last = db;	}	ndbfree(t);	return first;} /* *  open a single file */static Ndb*doopen(char *file){	Ndb *db; 	db = (Ndb*)malloc(sizeof(Ndb));	if(db == 0)		return 0;	memset(db, 0, sizeof(Ndb));	strncpy(db->file, file, sizeof(db->file)-1); 	if(ndbreopen(db) < 0){		free(db);		return 0;	} 	return db;} /* *  dump any cached information, forget the hash tables, and reopen a single file */intndbreopen(Ndb *db){	int fd;	Dir *d; 	/* forget what we know about the open files */	if(db->mtime){		_ndbcacheflush(db);		hffree(db);		close(Bfildes(&db->b));		Bterm(&db->b);		db->mtime = 0;	} 	/* try the open again */	fd = open(db->file, OREAD);	if(fd < 0)		return -1;	d = dirfstat(fd);	if(d == nil){		close(fd);		return -1;	} 	db->qid = d->qid;	db->mtime = d->mtime;	db->length = d->length;	Binits(&db->b, fd, OREAD, db->buf, sizeof(db->buf));	free(d);	return 0;} /* *  close the database files */voidndbclose(Ndb *db){	Ndb *nextdb; 	for(; db; db = nextdb){		nextdb = db->next;		_ndbcacheflush(db);		hffree(db);		close(Bfildes(&db->b));		Bterm(&db->b);		free(db);	}} /* *  free the hash files belonging to a db */static voidhffree(Ndb *db){	Ndbhf *hf, *next; 	for(hf = db->hf; hf; hf = next){		next = hf->next;		close(hf->fd);		free(hf);	}	db->hf = 0;} /* *  return true if any part of the database has changed */intndbchanged(Ndb *db){	Ndb *ndb;	Dir *d; 	for(ndb = db; ndb != nil; ndb = ndb->next){		d = dirfstat(Bfildes(&ndb->b));		if(d == nil)			continue;		if(ndb->qid.path != d->qid.path		|| ndb->qid.vers != d->qid.vers){			free(d);			return 1;		}		free(d);	}	return 0;}