/*  * 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 <ndb.h>#include <ndbhf.h> /* *  search for a tuple that has the given 'attr=val' and also 'rattr=x'. *  copy 'x' into 'buf' and return the whole tuple. * *  return 0 if not found. */char*csgetvalue(char *netroot, char *attr, char *val, char *rattr, Ndbtuple **pp){	Ndbtuple *t, *first, *last;	int n, linefound;	char line[1024];	int fd;	int oops = 0;	char *rv; 	if(pp)		*pp = nil;	rv = nil; 	if(netroot)		snprint(line, sizeof(line), "%s/cs", netroot);	else		strcpy(line, "/net/cs");	fd = open(line, ORDWR);	if(fd < 0)		return 0;	seek(fd, 0, 0);	snprint(line, sizeof(line), "!%s=%s %s=*", attr, val, rattr);	if(write(fd, line, strlen(line)) < 0){		close(fd);		return 0;	}	seek(fd, 0, 0); 	first = last = 0;	linefound = 0;	for(;;){		n = read(fd, line, sizeof(line)-2);		if(n <= 0)			break;		line[n] = '\n';		line[n+1] = 0; 		t = _ndbparseline(line);		if(t == 0)			continue;		if(first)			last->entry = t;		else			first = t;		last = t; 		while(last->entry)			last = last->entry; 		for(; t; t = t->entry){			if(linefound == 0){				if(strcmp(rattr, t->attr) == 0){					linefound = 1;					rv = strdup(t->val);				}			}		}	}	close(fd); 	if(oops){		werrstr("buffer too short");		ndbfree(first);		return nil;	} 	if(pp){		setmalloctag(first, getcallerpc(&netroot));		*pp = first;	} else		ndbfree(first); 	return rv;} Ndbtuple*csgetval(char *netroot, char *attr, char *val, char *rattr, char *buf){	Ndbtuple *t;	char *p; 	p = csgetvalue(netroot, attr, val, rattr, &t);	if(p == nil){		if(buf != nil)			*buf = 0;	} else {		if(buf != nil){			strncpy(buf, p, Ndbvlen-1);			buf[Ndbvlen-1] = 0;		}		free(p);	}	ndbsetmalloctag(t, getcallerpc(&netroot));	return t;}