glibc/SOURCES/glibc-rh1817513-39.patch

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2021-05-18 06:37:04 +00:00
commit abcc039d2e26b3c9c723d6419e086753a791b3d5
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Feb 7 20:06:32 2020 +0100
elf: Introduce the rtld-stubbed-symbols makefile variable
This generalizes a mechanism used for stack-protector support, so
that it can be applied to other symbols if required.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
diff --git a/elf/Makefile b/elf/Makefile
index 4ab73dc48d9ac126..a1ea44f231d8cec5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -474,21 +474,25 @@ $(objpfx)dl-allobjs.os: $(all-rtld-routines:%=$(objpfx)%.os)
# are compiled with special flags, and puts these modules into rtld-libc.a
# for us. Then we do the real link using rtld-libc.a instead of libc_pic.a.
-# If the compiler can do SSP, build the mapfile with dummy __stack_chk_fail
-# and __stack_chk_fail_local symbols defined, to prevent the real things
-# being dragged into rtld even though rtld is never built with stack-
-# protection.
+# These symbols need to be stubbed out during symbol discovery because
+# their implementation is provided differently in rtld, and the symbol
+# discovery mechanism is not compatible with the libc implementation
+# when compiled for libc.
+rtld-stubbed-symbols =
+
+# The GCC arguments that implement $(rtld-stubbed-symbols).
+rtld-stubbed-symbols-args = \
+ $(patsubst %,-Wl$(comma)--defsym=%=0, $(rtld-stubbed-symbols))
ifeq ($(have-ssp),yes)
-dummy-stack-chk-fail := -Wl,--defsym='__stack_chk_fail=0' \
- -Wl,--defsym='__stack_chk_fail_local=0'
-else
-dummy-stack-chk-fail :=
+# rtld is not built with the stack protector, so these references will
+# go away in the rebuilds.
+rtld-stubbed-symbols += __stack_chk_fail __stack_chk_fail_local
endif
$(objpfx)librtld.map: $(objpfx)dl-allobjs.os $(common-objpfx)libc_pic.a
@-rm -f $@T
- $(reloc-link) -o $@.o $(dummy-stack-chk-fail) \
+ $(reloc-link) -o $@.o $(rtld-stubbed-symbols-args) \
'-Wl,-(' $^ -lgcc '-Wl,-)' -Wl,-Map,$@T
rm -f $@.o
mv -f $@T $@