From a93d9e03a31ec14405cb3a09aa95413b67067380 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 17 Aug 2021 19:35:48 -0700 Subject: Extend struct r_debug to support multiple namespaces [BZ #15971] Glibc does not provide an interface for debugger to access libraries loaded in multiple namespaces via dlmopen. The current rtld-debugger interface is described in the file: elf/rtld-debugger-interface.txt under the "Standard debugger interface" heading. This interface only provides access to the first link-map (LM_ID_BASE). 1. Bump r_version to 2 when multiple namespaces are used. This triggers the GDB bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28236 2. Add struct r_debug_extended to extend struct r_debug into a linked-list, where each element correlates to an unique namespace. 3. Initialize the r_debug_extended structure. Bump r_version to 2 for the new namespace and add the new namespace to the namespace linked list. 4. Add _dl_debug_update to return the address of struct r_debug' of a namespace. 5. Add a hidden symbol, _r_debug_extended, for struct r_debug_extended. 6. Provide the symbol, _r_debug, with size of struct r_debug, as an alias of _r_debug_extended, for programs which reference _r_debug. This fixes BZ #15971. Reviewed-by: Florian Weimer --- csu/Makefile | 3 +++ csu/rtld-sizes.sym | 6 ++++++ 2 files changed, 9 insertions(+) create mode 100644 csu/rtld-sizes.sym (limited to 'csu') diff --git a/csu/Makefile b/csu/Makefile index 3054329cea..e2390e4a7d 100644 --- a/csu/Makefile +++ b/csu/Makefile @@ -88,6 +88,9 @@ endif before-compile += $(objpfx)abi-tag.h generated += abi-tag.h +# Put it here to generate it earlier. +gen-as-const-headers += rtld-sizes.sym + # These are the special initializer/finalizer files. They are always the # first and last file in the link. crti.o ... crtn.o define the global # "functions" _init and _fini to run the .init and .fini sections. diff --git a/csu/rtld-sizes.sym b/csu/rtld-sizes.sym new file mode 100644 index 0000000000..13924d5efd --- /dev/null +++ b/csu/rtld-sizes.sym @@ -0,0 +1,6 @@ +#include + +-- +R_DEBUG_SIZE sizeof (struct r_debug) +R_DEBUG_EXTENDED_SIZE sizeof (struct r_debug_extended) +R_DEBUG_EXTENDED_ALIGN __alignof (struct r_debug_extended) -- cgit 1.4.1