Patch series proposed upstream:

  <https://sourceware.org/pipermail/libc-alpha/2021-June/127473.html>

Author: Florian Weimer <fweimer@redhat.com>

Date:   Wed Jun 9 14:12:46 2021 +0200

    Install shared objects under their ABI names

    Previously, the installed objects were named like libc-2.33.so,

    and the ABI soname libc.so.6 was just a symbolic link.

    The Makefile targets to install these symbolic links are no longer

    needed after this, so they are removed with this commit.  The more

    general $(make-link) command (which invokes scripts/rellns-sh) is

    retained because other symbolic links are still needed.

diff --git a/INSTALL b/INSTALL

index 56ed01d4386ad8b7..7f054f422d990d8a 100644

--- a/INSTALL

+++ b/INSTALL

@@ -199,6 +199,16 @@ if 'CFLAGS' is specified it must enable optimization.  For example:

      RELRO and a read-only global offset table (GOT), at the cost of

      slightly increased program load times.

+'--disable-major-minor-libraries'

+     Do not install shared objects under file names that contain the

+     major and minor version of the GNU C Library.  By default, such

+     names are used, and the names defined by the ABI are provided as

+     symbolic links only.  This causes problems with certain package

+     managers during library upgrades and (in particular) downgrades, so

+     this option can be used to install these shared objects directly

+     under their ABI-defined names, without an additional indirection

+     via symbolic links.

+

 '--enable-pt_chown'

      The file 'pt_chown' is a helper binary for 'grantpt' (*note

      Pseudo-Terminals: Allocation.) that is installed setuid root to fix

diff --git a/Makefile b/Makefile

index 242d36de914c516f..c115c652a0b8c1ce 100644

--- a/Makefile

+++ b/Makefile

@@ -109,12 +109,6 @@ elf/ldso_install:

 # Ignore the error if we cannot update /etc/ld.so.cache.

 ifeq (no,$(cross-compiling))

 ifeq (yes,$(build-shared))

-install: install-symbolic-link

-.PHONY: install-symbolic-link

-install-symbolic-link: subdir_install

-	$(symbolic-link-prog) $(symbolic-link-list)

-	rm -f $(symbolic-link-list)

-

 install:

 	-test ! -x $(elf-objpfx)ldconfig || LC_ALL=C \

 	  $(elf-objpfx)ldconfig $(addprefix -r ,$(install_root)) \

diff --git a/Makerules b/Makerules

index d3f29d0b8991efc7..6efff78fbe44bdca 100644

--- a/Makerules

+++ b/Makerules

@@ -989,14 +989,12 @@ versioned := $(strip $(foreach so,$(install-lib.so),\

 install-lib.so-versioned := $(filter $(versioned), $(install-lib.so))

 install-lib.so-unversioned := $(filter-out $(versioned), $(install-lib.so))

-# For libraries whose soname have version numbers, we install three files:

+# For libraries whose soname have version numbers, we install two files:

 #	$(inst_libdir)/libfoo.so	-- for linking, symlink or ld script

-#	$(inst_slibdir)/libfoo.so.NN	-- for loading by SONAME, symlink

-#	$(inst_slibdir)/libfoo-X.Y.Z.so -- the real shared object file

+#	$(inst_slibdir)/libfoo.so.NN	-- for loading by SONAME

 install-lib-nosubdir: $(install-lib.so-unversioned:%=$(inst_slibdir)/%) \

 		      $(foreach L,$(install-lib.so-versioned),\

 				$(inst_libdir)/$L \

-				$(inst_slibdir)/$(L:.so=)-$(version).so \

 				$(inst_slibdir)/$L$($L-version))

 # Install all the unversioned shared libraries.

@@ -1029,35 +1027,10 @@ ln -f $(objpfx)/$(@F) $@

 endef

 endif

-ifeq (yes,$(build-shared))

-ifeq (no,$(cross-compiling))

-symbolic-link-prog := $(elf-objpfx)sln

-symbolic-link-list := $(elf-objpfx)symlink.list

-define make-shlib-link

-echo `$(..)scripts/rellns-sh -p $< $@` $@ >> $(symbolic-link-list)

-endef

-else # cross-compiling

-# We need a definition that can be used by elf/Makefile's install rules.

-symbolic-link-prog = $(LN_S)

-endif

-endif

-ifndef make-shlib-link

-define make-shlib-link

-rm -f $@

-$(LN_S) `$(..)scripts/rellns-sh -p $< $@` $@

-endef

-endif

-

 ifdef libc.so-version

-# For a library specified to be version N, install three files:

-# libc.so	->	libc.so.N	(e.g. libc.so.6)

-# libc.so.6	->	libc-VERSION.so	(e.g. libc-1.10.so)

-

-$(inst_slibdir)/libc.so$(libc.so-version): $(inst_slibdir)/libc-$(version).so \

-					   $(+force)

-	$(make-shlib-link)

-$(inst_slibdir)/libc-$(version).so: $(common-objpfx)libc.so $(+force)

+$(inst_slibdir)/libc.so$(libc.so-version): $(common-objpfx)libc.so $(+force)

 	$(do-install-program)

+

 install: $(inst_slibdir)/libc.so$(libc.so-version)

 # This fragment of linker script gives the OUTPUT_FORMAT statement

@@ -1125,15 +1098,7 @@ include $(o-iterator)

 generated += $(foreach o,$(versioned),$o$($o-version))

 define o-iterator-doit

-$(inst_slibdir)/$o$($o-version): $(inst_slibdir)/$(o:.so=)-$(version).so \

-				 $(+force);

-	$$(make-shlib-link)

-endef

-object-suffixes-left := $(versioned)

-include $(o-iterator)

-

-define o-iterator-doit

-$(inst_slibdir)/$(o:.so=)-$(version).so: $(objpfx)$o $(+force);

+$(inst_slibdir)/$o$($o-version): $(objpfx)$o $(+force);

 	$$(do-install-program)

 endef

 object-suffixes-left := $(versioned)

diff --git a/elf/Makefile b/elf/Makefile

index 1751f5ec6772eceb..02f634c19241949f 100644

--- a/elf/Makefile

+++ b/elf/Makefile

@@ -628,20 +628,14 @@ $(objpfx)trusted-dirs.st: Makefile $(..)Makeconfig

 CPPFLAGS-dl-load.c += -I$(objpfx). -I$(csu-objpfx).

 ifeq (yes,$(build-shared))

-$(inst_slibdir)/$(rtld-version-installed-name): $(objpfx)ld.so $(+force)

+$(inst_rtlddir)/$(rtld-installed-name): $(objpfx)ld.so $(+force)

 	$(make-target-directory)

 	$(do-install-program)

-$(inst_rtlddir)/$(rtld-installed-name): \

-  $(inst_slibdir)/$(rtld-version-installed-name) \

-  $(inst_slibdir)/libc-$(version).so

-	$(make-target-directory)

-	$(make-shlib-link)

-

 # Special target called by parent to install just the dynamic linker.

 .PHONY: ldso_install

 ldso_install: $(inst_rtlddir)/$(rtld-installed-name)

-endif

+endif # $(build-shared)

 # Workarounds for ${exec_prefix} expansion in configure variables.