From a46a3c8dbf32a1e3ece671f973034581543411b9 Mon Sep 17 00:00:00 2001
From: kib <kib@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Wed, 22 Apr 2015 10:59:05 +0000
Subject: [PATCH] MFC r281549: Implement support for -z global linker option.

git-svn-id: svn://svn.freebsd.org/base/stable/10@281849 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 libexec/rtld-elf/rtld.c | 47 ++++++++++++++++++++++++++---------------
 libexec/rtld-elf/rtld.h |  1 +
 2 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 84d1c80f6..cef0c429b 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -1150,8 +1150,8 @@ digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
 		    obj->z_noopen = true;
 		if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
 		    obj->z_origin = true;
-		/*if (dynp->d_un.d_val & DF_1_GLOBAL)
-		    XXX ;*/
+		if (dynp->d_un.d_val & DF_1_GLOBAL)
+		    obj->z_global = true;
 		if (dynp->d_un.d_val & DF_1_BIND_NOW)
 		    obj->bind_now = true;
 		if (dynp->d_un.d_val & DF_1_NODELETE)
@@ -1775,22 +1775,35 @@ init_dag(Obj_Entry *root)
 }
 
 static void
-process_nodelete(Obj_Entry *root)
+process_z(Obj_Entry *root)
 {
 	const Objlist_Entry *elm;
+	Obj_Entry *obj;
 
 	/*
-	 * Walk over object DAG and process every dependent object that
-	 * is marked as DF_1_NODELETE. They need to grow their own DAG,
-	 * which then should have its reference upped separately.
+	 * Walk over object DAG and process every dependent object
+	 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
+	 * to grow their own DAG.
+	 *
+	 * For DF_1_GLOBAL, DAG is required for symbol lookups in
+	 * symlook_global() to work.
+	 *
+	 * For DF_1_NODELETE, the DAG should have its reference upped.
 	 */
 	STAILQ_FOREACH(elm, &root->dagmembers, link) {
-		if (elm->obj != NULL && elm->obj->z_nodelete &&
-		    !elm->obj->ref_nodel) {
-			dbg("obj %s nodelete", elm->obj->path);
-			init_dag(elm->obj);
-			ref_dag(elm->obj);
-			elm->obj->ref_nodel = true;
+		obj = elm->obj;
+		if (obj == NULL)
+			continue;
+		if (obj->z_nodelete && !obj->ref_nodel) {
+			dbg("obj %s -z nodelete", obj->path);
+			init_dag(obj);
+			ref_dag(obj);
+			obj->ref_nodel = true;
+		}
+		if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
+			dbg("obj %s -z global", obj->path);
+			objlist_push_tail(&list_global, obj);
+			init_dag(obj);
 		}
 	}
 }
@@ -2961,13 +2974,13 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
 		initlist_add_objects(obj, &obj->next, &initlist);
 	    }
 	    /*
-	     * Process all no_delete objects here, given them own
-	     * DAGs to prevent their dependencies from being unloaded.
-	     * This has to be done after we have loaded all of the
-	     * dependencies, so that we do not miss any.
+	     * Process all no_delete or global objects here, given
+	     * them own DAGs to prevent their dependencies from being
+	     * unloaded.  This has to be done after we have loaded all
+	     * of the dependencies, so that we do not miss any.
 	     */
 	    if (obj != NULL)
-		process_nodelete(obj);
+		process_z(obj);
 	} else {
 	    /*
 	     * Bump the reference counts for objects on this DAG.  If
diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h
index e16e46a68..2fef9efbf 100644
--- a/libexec/rtld-elf/rtld.h
+++ b/libexec/rtld-elf/rtld.h
@@ -264,6 +264,7 @@ typedef struct Struct_Obj_Entry {
     bool z_loadfltr : 1;	/* Immediately load filtees */
     bool z_interpose : 1;	/* Interpose all objects but main */
     bool z_nodeflib : 1;	/* Don't search default library path */
+    bool z_global : 1;		/* Make the object global */
     bool ref_nodel : 1;		/* Refcount increased to prevent dlclose */
     bool init_scanned: 1;	/* Object is already on init list. */
     bool on_fini_list: 1;	/* Object is already on fini list. */
-- 
2.42.0