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, 5 insertions, 5 deletions

diff --git a/libexec/ld.so/loader.c b/libexec/ld.so/loader.c
index fdda79de64c..22302d9f711 100644
--- a/libexec/ld.so/loader.c
+++ b/libexec/ld.so/loader.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: loader.c,v 1.132 2013/04/05 12:58:03 kurt Exp $ */
+/*	$OpenBSD: loader.c,v 1.133 2013/06/01 09:57:55 miod Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -51,8 +51,6 @@
 /*
  * Local decls.
  */
-static char *_dl_getenv(const char *, char **);
-static void _dl_unsetenv(const char *, char **);
 unsigned long _dl_boot(const char **, char **, const long, long *);
 void _dl_debug_state(void);
 void _dl_setup_env(char **);
@@ -257,6 +255,8 @@ _dl_setup_env(char **envp)
 		}
 	}
 	_dl_so_envp = envp;
+
+	_dl_trace_setup(envp);
 }
 
 int
@@ -914,7 +914,7 @@ _dl_call_init_recurse(elf_object_t *object, int initfirst)
 	object->status |= STAT_INIT_DONE;
 }
 
-static char *
+char *
 _dl_getenv(const char *var, char **env)
 {
 	const char *ep;
@@ -932,7 +932,7 @@ _dl_getenv(const char *var, char **env)
 	return(NULL);
 }
 
-static void
+void
 _dl_unsetenv(const char *var, char **env)
 {
 	char *ep;