From: Serhei Makarov <serhei@serhei.io>
Date: Mon, 3 Feb 2025 21:45:20 +0000 (-0500)
Subject: fixup for DRAFT e38ce78: cache Elf * in open_elf
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d4c0992f6dda5ed9e62190a808a2cd4d651a9220;p=thirdparty%2Felfutils.git

fixup for DRAFT e38ce78: cache Elf * in open_elf

Caching behaviour is improving. The commented assert still catches
some cases where a redundant Elf * is being created.

* dwfl_module_getdwarf.c (open_elf): Cache file->elf in Dwfl_Process_Tracker.
---

diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index 6f98c02b..6aa87fdf 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -79,6 +79,18 @@ open_elf (Dwfl_Module *mod, struct dwfl_file *file)
   if (error != DWFL_E_NOERROR)
     return error;
 
+  /* Cache file->elf in Dwfl_Process_Tracker if available: */
+  if (mod->dwfl->tracker != NULL && file->name != NULL)
+    {
+      dwfltracker_elftab_ent *ent = __libdwfl_process_tracker_elftab_find (mod->dwfl->tracker, file->name, false/* should_resize */);
+      if (ent != NULL)
+	{
+	  /* assert(ent->elf == NULL || ent->elf == file->elf); */ /* TODO(PRERELEASE): Guard against redundant/leaked Elf *. */
+	  assert(ent->fd == file->fd); /* TODO(PRERELEASE): Guard against redundant open. */
+	  ent->elf = file->elf;
+	}
+    }
+
   GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (file->elf, &ehdr_mem);
   if (ehdr == NULL)
     {
diff --git a/libdwfl/dwfl_process_tracker_find_elf.c b/libdwfl/dwfl_process_tracker_find_elf.c
index d1871071..20c48bea 100644
--- a/libdwfl/dwfl_process_tracker_find_elf.c
+++ b/libdwfl/dwfl_process_tracker_find_elf.c
@@ -82,7 +82,6 @@ dwfl_process_tracker_find_elf (Dwfl_Module *mod,
   /* XXX fd < 0 implies elf_from_remote_memory, uses base, not cacheable */
   if (tracker != NULL && ent != NULL && fd >= 0 && *file_name != NULL)
     {
-      /* TODO(WIP): *elfp may be NULL here, need to be populated later. */
       ent->elf = *elfp;
       ent->fd = fd;
       rc = fstat(fd, &sb);