Introduce ltrace(1). This tool works with ld.so to inject utrace record for

each plt call, allowing to trace a binary linked against shared library at the
public function call level.

To do so, ltrace(1) sets up some environment variables to enable plt tracing
in ld.so, and invokes ktrace(2) for utrace events. ld.so will force lazy
binding and will send an utrace record in the plt resolver, without updating
the plt.

Minimal filtering capabilities are provided, inspired by Solaris' truss -u,
to limit tracing to libraries and/or symbol names. Non-traced libraries and
symbols will have the regular resolver processing, with the expected plt
update.

"Get it in" deraadt

1 files changed, 9 insertions, 4 deletions

diff --git a/libexec/ld.so/hppa/ldasm.S b/libexec/ld.so/hppa/ldasm.S
index 644b0ddfa60..684a898fa52 100644
--- a/libexec/ld.so/hppa/ldasm.S
+++ b/libexec/ld.so/hppa/ldasm.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldasm.S,v 1.9 2013/04/05 12:58:03 kurt Exp $	*/
+/*	$OpenBSD: ldasm.S,v 1.10 2013/06/01 09:57:58 miod Exp $	*/
 
 /*
  * Copyright (c) 2004 Michael Shalayeff
@@ -149,9 +149,8 @@ ENTRY(_dl_bind_start,32)
 	bl	_dl_bind, rp
 	copy	r21, r19
 
-	/* load &func and sl from plt entry returned */
-	ldw	0(ret0), r21
-	ldw	4(ret0), r19
+	copy	ret0, r21	/* &func */
+	copy	ret1, r19	/* sl */
 
 	ldw	HPPA_FRAME_ARG(0)(r3), arg0
 	ldw	HPPA_FRAME_ARG(1)(r3), arg1
@@ -281,6 +280,12 @@ ENTRY(_dl_getcwd,0)
 	nop
 EXIT(_dl_getcwd)
 
+ENTRY(_dl_utrace,0)
+	SYSCALL(utrace)
+	bv	r0(rp)
+	nop
+EXIT(_dl_utrace)
+
 ENTRY(_dl_sigprocmask,0)
 	stw	arg2, HPPA_FRAME_ARG(2)(sp)