[PATCH v5 15/22] elf: Run constructors if executable has a soname of a dependency

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

The DSO constructor should not be ignored if the main executable
has the SONAME set to a dependency.  It fixes the case where
(using the scripts/dso-ordering-test.py definition):

  {}->a->b->c;soname({})=c

Where the constructors should return

  c>b>a>{}<a<b<c

Checked on x86_64-linux-gnu.
---
 elf/dl-load.c            | 9 +++++++--
 elf/dso-sort-tests-1.def | 5 ++++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 4a0ff9d010..d585e1795d 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1998,13 +1998,18 @@ _dl_map_object (struct link_map *loader, const char *name,
   assert (nsid >= 0);
   assert (nsid < GL(dl_nns));
 
+  /* Special case: trying to map itself.  */
+  if (name[0] == '\0')
+    return GL(dl_ns)[nsid]._ns_loaded;
+
   /* Look for this name among those already loaded.  */
   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))
+	 yet been opened or the executable itself.  */
+      if (__glibc_unlikely ((l->l_faked | l->l_removed) != 0
+			    || l->l_type == lt_executable))
 	continue;
       if (!_dl_name_match_p (name, l))
 	{
diff --git a/elf/dso-sort-tests-1.def b/elf/dso-sort-tests-1.def
index 5f7f18ef27..2228910c0d 100644
--- a/elf/dso-sort-tests-1.def
+++ b/elf/dso-sort-tests-1.def
@@ -50,7 +50,10 @@ output: e>d>c>b>a>{}<a<b<c<d<e
 # Test if init/fini ordering behavior is proper, despite main program with
 # an soname that may cause confusion
 tst-dso-ordering10: {}->a->b->c;soname({})=c
-output: b>a>{}<a<b
+output: c>b>a>{}<a<b<c
+# Same as before, but setting the soname as a direct dependency.
+tst-dso-ordering11: {}->a->b->c;soname({})=a
+output: c>b>a>{}<a<b<c
 
 # Complex example from Bugzilla #15311, under-linked and with circular
 # relocation(dynamic) dependencies. While this is technically unspecified, the
-- 
2.32.0