telnetd: let the kernel place the shared segment in segattach() (thanks kenji arisawa)

sys/src/cmd/ip/telnetd.c

@@ -541,23 +541,17 @@ xlocsub(Biobuf *bp, uchar *sub, int n)
 }
 
 /*
- *  create a shared segment.  Make is start 2 meg higher than the current
- *  end of process memory.
+ *  create a shared segment.
  */
 void*
 share(ulong len)
 {
-	uchar *vastart;
+	void *v;
 
-	vastart = sbrk(0);
-	if(vastart == (void*)-1)
-		return 0;
-	vastart += 2*1024*1024;
-
-	if(segattach(0, "shared", vastart, len) == (void*)-1)
-		return 0;
-
-	return vastart;
+	v = segattach(0, "shared", 0, len);
+	if(v == (void*)-1)
+		return nil;
+	return v;
 }
 
 /*