From 76fb722224d35f6326342f85f34f5b50ed260294 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Thu, 16 May 2013 12:23:27 -0700
Subject: [PATCH] stapdyn: implement tapset target() and stp_pid()

Add fields for the target pid and stapdyn's own pid to the new
stp_session_attributes, and expose them in the tapset.
---
 runtime/dyninst/session_attributes.c | 17 +++++++++++++----
 runtime/dyninst/session_attributes.h |  2 ++
 stapdyn/mutatee.h                    |  2 ++
 stapdyn/mutator.cxx                  | 11 +++++++++++
 tapset/dyninst/context.stp           | 10 ++++++++--
 5 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/runtime/dyninst/session_attributes.c b/runtime/dyninst/session_attributes.c
index a51ef2a35..7a3101643 100644
--- a/runtime/dyninst/session_attributes.c
+++ b/runtime/dyninst/session_attributes.c
@@ -14,14 +14,13 @@
 static struct _stp_session_attributes _stp_init_session_attributes = {
 	.log_level = 0,
 	.suppress_warnings = 0,
+	.stp_pid = 0,
+	.target = 0,
 };
 
 static void stp_session_attributes_init(void)
 {
-	stp_session_attributes()->log_level
-	    = _stp_init_session_attributes.log_level;
-	stp_session_attributes()->suppress_warnings
-	    = _stp_init_session_attributes.suppress_warnings;
+	*stp_session_attributes() = _stp_init_session_attributes;
 }
 
 static int stp_session_attribute_setter(const char *name, const char *value)
@@ -38,6 +37,16 @@ static int stp_session_attribute_setter(const char *name, const char *value)
 		    = strtoul(value, NULL, 10);
 		return 0;
 	}
+	else if (strcmp(name, "@stp_pid") == 0) {
+		_stp_init_session_attributes.stp_pid
+		    = strtoul(value, NULL, 10);
+		return 0;
+	}
+	else if (strcmp(name, "@target") == 0) {
+		_stp_init_session_attributes.target
+		    = strtoul(value, NULL, 10);
+		return 0;
+	}
 	return -EINVAL;
 }
 
diff --git a/runtime/dyninst/session_attributes.h b/runtime/dyninst/session_attributes.h
index b96e2455c..bb46dd3dd 100644
--- a/runtime/dyninst/session_attributes.h
+++ b/runtime/dyninst/session_attributes.h
@@ -12,6 +12,8 @@
 struct _stp_session_attributes {
 	unsigned long log_level;
 	unsigned long suppress_warnings;
+	unsigned long stp_pid;
+	unsigned long target;
 };
 
 static void stp_session_attributes_init(void);
diff --git a/stapdyn/mutatee.h b/stapdyn/mutatee.h
index 996ea4809..b7abb88c7 100644
--- a/stapdyn/mutatee.h
+++ b/stapdyn/mutatee.h
@@ -52,6 +52,8 @@ class mutatee {
     mutatee(BPatch_process* process);
     ~mutatee();
 
+    pid_t process_id() { return pid; }
+
     bool operator==(BPatch_process* other) { return process == other; }
 
     // Inject the stap module into the target process
diff --git a/stapdyn/mutator.cxx b/stapdyn/mutator.cxx
index 682bb3c2b..1b4adc936 100644
--- a/stapdyn/mutator.cxx
+++ b/stapdyn/mutator.cxx
@@ -346,6 +346,17 @@ mutator::init_session_attributes()
   if (rc != 0)
     stapwarn() << "couldn't set 'suppress_warnings' global" << endl;
 
+  rc = global_setter("@stp_pid", lex_cast(getpid()).c_str());
+  if (rc != 0)
+    stapwarn() << "couldn't set 'stp_pid' global" << endl;
+
+  if (target_mutatee)
+    {
+      rc = global_setter("@target", lex_cast(target_mutatee->process_id()).c_str());
+      if (rc != 0)
+        stapwarn() << "couldn't set 'target' global" << endl;
+    }
+
   return;
 }
 
diff --git a/tapset/dyninst/context.stp b/tapset/dyninst/context.stp
index c9519f8f1..b35b14a6c 100644
--- a/tapset/dyninst/context.stp
+++ b/tapset/dyninst/context.stp
@@ -95,11 +95,17 @@ function user_mode:long ()
 
 // TODO function is_return:long ()
 
-// TODO function target:long ()
+function target:long ()
+%{ /* pure */ /* unprivileged */
+	STAP_RETVALUE = stp_session_attributes()->target;
+%}
 
 // TODO function module_name:string ()
 
-// TODO function stp_pid:long ()
+function stp_pid:long ()
+%{ /* pure */ /* unprivileged */
+	STAP_RETVALUE = stp_session_attributes()->stp_pid;
+%}
 
 // TODO function remote_id:long ()
 
-- 
2.43.5