From: Serhei Makarov <serhei@serhei.io>
Date: Fri, 14 Feb 2025 15:02:49 +0000 (-0500)
Subject: DRAFT libdwfl: add dwfl_process_tracker_find_pid
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=55fe0effdc061a6a1ab75f3c8afbc800e2d7474c;p=thirdparty%2Felfutils.git

DRAFT libdwfl: add dwfl_process_tracker_find_pid

* libdwfl/libdwfl.h (dwfl_process_tracker_find_pid): New function.
* libdwfl/dwfl_process_tracker.h (dwfl_process_tracker_find_pid):
  New function; find a Dwfl in the dwfltab or create one using the
  provided callback.
* libdw/libdw.map: Add dwfl_process_tracker_find_pid.
---

diff --git a/libdw/libdw.map b/libdw/libdw.map
index 5f43248a..ce990a09 100644
--- a/libdw/libdw.map
+++ b/libdw/libdw.map
@@ -392,4 +392,5 @@ ELFUTILS_0.193 {
     dwfl_begin_with_tracker;
     dwfl_process_tracker_end;
     dwfl_process_tracker_find_elf;
+    dwfl_process_tracker_find_pid;
 } ELFUTILS_0.192;
diff --git a/libdwfl/dwfl_process_tracker.c b/libdwfl/dwfl_process_tracker.c
index f1d1feb5..89fd2b36 100644
--- a/libdwfl/dwfl_process_tracker.c
+++ b/libdwfl/dwfl_process_tracker.c
@@ -65,6 +65,27 @@ Dwfl *dwfl_begin_with_tracker (Dwfl_Process_Tracker *tracker)
   return dwfl;
 }
 
+Dwfl *dwfl_process_tracker_find_pid (Dwfl_Process_Tracker *tracker,
+				     pid_t pid,
+				     Dwfl *(*callback) (Dwfl_Process_Tracker *,
+							pid_t, void *),
+				     void *arg)
+{
+  Dwfl *dwfl = NULL;
+  dwfltracker_dwfl_info *ent = dwfltracker_dwfltab_find(&tracker->dwfltab, pid);
+  if (ent != NULL && !ent->invalid)
+    dwfl = ent->dwfl;
+  if (dwfl == NULL && callback != NULL)
+    dwfl = callback(tracker, pid, arg);
+  if (dwfl != NULL)
+    {
+      assert (dwfl->tracker == tracker);
+      /* XXX: dwfl added to dwfltab when dwfl->process set in dwfl_attach_state. */
+    }
+
+  return dwfl;
+}
+
 void __libdwfl_add_dwfl_to_tracker (Dwfl *dwfl) {
   Dwfl_Process_Tracker *tracker = dwfl->tracker;
   assert (tracker != NULL);
diff --git a/libdwfl/libdwfl.h b/libdwfl/libdwfl.h
index c27da887..16b351cf 100644
--- a/libdwfl/libdwfl.h
+++ b/libdwfl/libdwfl.h
@@ -133,6 +133,17 @@ extern Dwfl_Process_Tracker *dwfl_process_tracker_begin (const Dwfl_Callbacks *c
 extern Dwfl *dwfl_begin_with_tracker (Dwfl_Process_Tracker *tracker)
   __nonnull_attribute__ (1);
 
+/* Find the Dwfl corresponding to PID.  If CALLBACK is non-NULL
+   and the Dwfl has not been created, invoke CALLBACK to create
+   the Dwfl and then store it in the tracker.  */
+extern Dwfl *dwfl_process_tracker_find_pid (Dwfl_Process_Tracker *tracker,
+                                            pid_t pid,
+                                            Dwfl *(*callback) (Dwfl_Process_Tracker *tracker,
+                                                               pid_t pid,
+                                                               void *arg),
+                                            void *arg)
+  __nonnull_attribute__ (1);
+
 /* End a multi-process session.  */
 extern void dwfl_process_tracker_end (Dwfl_Process_Tracker *tracker);