From: Serhei Makarov <serhei@serhei.io>
Date: Fri, 14 Feb 2025 21:45:46 +0000 (-0500)
Subject: fixup for DRAFT 97df2fc6: elftab should retain Elf * via refcount
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cca44c9409e0e610bdc3a1f2d90f4dce5de4ce01;p=thirdparty%2Felfutils.git

fixup for DRAFT 97df2fc6: elftab should retain Elf * via refcount

* libdwfl/dwfl_module_getdwarf.c (open_elf): Increment Elf * refcount.
* libdwfl/dwfl_process_tracker_find_elf.c (dwfl_process_tracker_find_elf):
  Increment Elf * refcount.
---

diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index ed584659..a84353af 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -88,6 +88,8 @@ open_elf (Dwfl_Module *mod, struct dwfl_file *file)
 	  /* 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;
+	  /* XXX Dwfl_Process_Tracker also holds the Elf * jointly with the caller: */
+	  ent->elf->ref_count++;
 	}
     }
 
diff --git a/libdwfl/dwfl_process_tracker_find_elf.c b/libdwfl/dwfl_process_tracker_find_elf.c
index 2d8ccbd2..bfc29186 100644
--- a/libdwfl/dwfl_process_tracker_find_elf.c
+++ b/libdwfl/dwfl_process_tracker_find_elf.c
@@ -32,6 +32,9 @@
 #endif
 
 #include <sys/stat.h>
+#include "../libelf/libelfP.h"
+/* XXX: Private header needed for Elf * ref_count field. */
+/* TODO: Consider dup_elf() rather than direct ref_count access. */
 
 #include "libdwflP.h"
 
@@ -61,6 +64,9 @@ dwfl_process_tracker_find_elf (Dwfl_Module *mod,
 	    ent = NULL; /* file modified, fall back to uncached behaviour */
 	  else
 	    {
+	      /* XXX Caller also holds the Elf * jointly with prior owners: */
+	      if (ent->elf != NULL)
+		ent->elf->ref_count++;
 	      *elfp = ent->elf;
 	      *file_name = strdup(ent->module_name);
 	      return ent->fd;
@@ -87,6 +93,9 @@ dwfl_process_tracker_find_elf (Dwfl_Module *mod,
   if (tracker != NULL && ent != NULL && fd >= 0 && *file_name != NULL)
     {
       /* TODO(WIP): *elfp may be NULL here, need to be populated later. */
+      /* XXX Dwfl_Process_Tracker also holds the Elf * jointly with the caller: */
+      if (*elfp != NULL)
+	(*elfp)->ref_count++;
       ent->elf = *elfp;
       ent->fd = fd;
       rc = fstat(fd, &sb);