1 files changed, 44 insertions, 0 deletions
diff --git a/runtime/sym.c b/runtime/sym.c
index 763af16d..3843a3a5 100644
--- a/runtime/sym.c
+++ b/runtime/sym.c
@@ -20,6 +20,50 @@
  * @{
  */
 
+static const char * _stp_kallsyms_lookup (
+	unsigned long addr,
+	unsigned long *symbolsize,
+	unsigned long *offset,
+	char **modname,
+	char *namebuf)
+{
+	unsigned begin = 0;
+	unsigned end = stap_num_symbols;
+	/*const*/ struct stap_symbol* s;
+
+	/* binary search on index [begin,end) */
+	do {
+		unsigned mid = (begin + end) / 2;
+		if (addr < stap_symbols[mid].addr)
+			end = mid;
+		else
+			begin = mid;
+	} while (begin + 1 < end);
+	/* result index in $begin, guaranteed between [0,stap_num_symbols) */
+
+	s = & stap_symbols [begin];
+	if (addr < s->addr)
+		return NULL;
+	else {
+		if (offset) *offset = addr - s->addr;
+		if (modname) *modname = (char *) s->modname;
+		if (symbolsize) {
+			if ((begin + 1) < stap_num_symbols)
+				*symbolsize = stap_symbols[begin+1].addr - s->addr;
+			else
+				*symbolsize = 0;
+			// NB: This is only a heuristic.  Sometimes there are large
+			// gaps between text areas of modules.
+		}
+		if (namebuf) {
+			strlcpy (namebuf, s->symbol, KSYM_NAME_LEN+1);
+			return namebuf;
+		}
+		else
+			return s->symbol;
+	}
+}
+
 /** Write addresses symbolically into a String
  * @param str String
  * @param address The address to lookup.