[RFC,v4,08/15] Abstract the loaded-DSO search code into a private helper function

Message ID ded1a27a8d05cc6c5669602b09fca8887c5f0fb1.1585588166.git.vivek@collabora.com
State Superseded
Headers show
Series
  • Proof-of-Concept implementation of RTLD_SHARED for dlmopen
Related show

Commit Message

H.J. Lu via Libc-alpha March 30, 2020, 5:43 p.m.
---
 elf/dl-load.c              | 38 ++++++++++++++++++++++++++++++++++++++
 sysdeps/generic/ldsodefs.h |  4 ++++
 2 files changed, 42 insertions(+)

-- 
2.11.0

Patch

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 221589e292..d4d6a6318b 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1936,6 +1936,44 @@  _dl_find_proxy (Lmid_t nsid, const char *name)
   return NULL;
 }
 
+/* search for a shared object in a given namespace.  */
+struct link_map *
+_dl_find_dso (const char *name, Lmid_t nsid)
+{
+  struct link_map *l;
+
+  for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
+    {
+      /* If the requested name matches the soname of a loaded object,
+	 use that object.  Elide this check for names that have not
+	 yet been opened.  */
+      if (__glibc_unlikely ((l->l_faked | l->l_removed) != 0))
+	continue;
+      if (!_dl_name_match_p (name, l))
+	{
+	  const char *soname;
+
+	  if (__glibc_likely (l->l_soname_added)
+	      || l->l_info[DT_SONAME] == NULL)
+	    continue;
+
+	  soname = ((const char *) D_PTR (l, l_info[DT_STRTAB])
+		    + l->l_info[DT_SONAME]->d_un.d_val);
+	  if (strcmp (name, soname) != 0)
+	    continue;
+
+	  /* We have a match on a new name -- cache it.  */
+	  add_name_to_object (l, soname);
+	  l->l_soname_added = 1;
+	}
+
+      /* We have a match.  */
+      return l;
+    }
+
+  return NULL;
+}
+
 /* Map in the shared object file NAME.  */
 
 struct link_map *
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index d3113ff4d8..3b5c5e9147 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1184,6 +1184,10 @@  extern void _dl_show_scope (struct link_map *new, int from)
 extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr);
 rtld_hidden_proto (_dl_find_dso_for_object)
 
+extern struct link_map *_dl_find_dso (const char *name, Lmid_t nsid);
+rtld_hidden_proto (_dl_find_dso)
+
+
 /* Initialization which is normally done by the dynamic linker.  */
 extern void _dl_non_dynamic_init (void)
      attribute_hidden;