From 1005d3d05362de368b1ea7aeb8eb20cee993e122 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Fri, 14 Jul 2023 16:38:03 +0300 Subject: [PATCH] rtld: fix dlopen() for an object that is already mapped but not yet initialized For instance, dso might be mapped as needed but not yet initialized from the other subtree of needed objects, while current object' constructor does dlopen() for the dso. Right now rtld does relocations and other processing based on the arrival of new objects in the global list, which is not happens there. Directly check for the initialization state of the object, for which we would return the handle. One practical use case of this support is e.g. dlopen("libthr.so", RTLD_NOLOAD) by libraries that are threading-aware but happy to live with libc pthread shims if the program is not multithreaded. Reviewed by: tijl Sponsored by: The FreeBSD Foundation MFC after: 2 weeks --- libexec/rtld-elf/rtld.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c index 5c96405be62..83315d5023b 100644 --- a/libexec/rtld-elf/rtld.c +++ b/libexec/rtld-elf/rtld.c @@ -3714,7 +3714,6 @@ static Obj_Entry * dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, int mode, RtldLockState *lockstate) { - Obj_Entry *old_obj_tail; Obj_Entry *obj; Objlist initlist; RtldLockState mlockstate; @@ -3731,7 +3730,6 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, } GDB_STATE(RT_ADD,NULL); - old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); obj = NULL; if (name == NULL && fd == -1) { obj = obj_main; @@ -3744,9 +3742,9 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, obj->dl_refcount++; if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) objlist_push_tail(&list_global, obj); - if (globallist_next(old_obj_tail) != NULL) { - /* We loaded something new. */ - assert(globallist_next(old_obj_tail) == obj); + + if (!obj->init_done) { + /* We loaded something new and have to init something. */ if ((lo_flags & RTLD_LO_DEEPBIND) != 0) obj->symbolic = true; result = 0;