new

src/libndb/csgetval.c

@@ -0,0 +1,107 @@
+#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);
+	}
+	return t;
+}