[glibc/azanella/rtld-shared] elf: Abstract loaded-DSO search code into a helper function

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=22b419be4e23df6fead108b7a40ea7b019aa9f13

commit 22b419be4e23df6fead108b7a40ea7b019aa9f13
Author: Vivek Das Mohapatra <vivek@collabora.com>
Date:   Thu Jul 8 17:32:49 2021 +0100

    elf: Abstract loaded-DSO search code into a helper function
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 elf/dl-load.c              | 44 ++++++++++++++++++++++++++++++--------------
 sysdeps/generic/ldsodefs.h |  4 ++++
 2 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 650e4edc35..fb23ba632b 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2027,24 +2027,13 @@ open_path (const char *name, size_t namelen, int mode,
   return -1;
 }
 
-/* Map in the shared object file NAME.  */
-
+/* Search for a shared object in a given namespace.  */
 struct link_map *
-_dl_map_object (struct link_map *loader, const char *name,
-		int type, int trace_mode, int mode, Lmid_t nsid)
+_dl_find_dso (const char *name, Lmid_t nsid)
 {
-  int fd;
-  const char *origname = NULL;
-  char *realname;
-  char *name_copy;
   struct link_map *l;
-  struct filebuf fb;
 
-  assert (nsid >= 0);
-  assert (nsid < GL(dl_nns));
-
-  /* Look for this name among those already loaded.  */
-  for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
+  for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; 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
@@ -2073,6 +2062,33 @@ _dl_map_object (struct link_map *loader, const char *name,
       return l;
     }
 
+  return NULL;
+}
+
+/* Map in the shared object file NAME.  */
+
+struct link_map *
+_dl_map_object (struct link_map *loader, const char *name,
+		int type, int trace_mode, int mode, Lmid_t nsid)
+{
+  int fd;
+  const char *origname = NULL;
+  char *realname;
+  char *name_copy;
+  struct link_map *l;
+  struct filebuf fb;
+
+  assert (nsid >= 0);
+  assert (nsid < GL(dl_nns));
+
+  /* Look for this name among those already loaded.  */
+  l = _dl_find_dso (name, nsid);
+
+  if (l != NULL)
+    {
+      return l;
+    }
+
   /* Display information if we are debugging.  */
   if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
       && loader != NULL)
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 9c15259236..22f3fea436 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1287,6 +1287,10 @@ 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;