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Revision 3dbae15538972c9e1578cb216964c2840361a538 authored by Gustavo A. R. Silva on 15 February 2020, 01:03:12 UTC, committed by Dmitry Torokhov on 15 February 2020, 01:19:22 UTC 
Input: cyapa - replace zero-length array with flexible-array member
 
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200214172132.GA28389@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
1 parent 94bef5d
Raw File
Makefile.modfinal 
# SPDX-License-Identifier: GPL-2.0-only
# ===========================================================================
# Module final link
# ===========================================================================

PHONY := __modfinal
__modfinal:

include $(srctree)/scripts/Kbuild.include

# for c_flags
include $(srctree)/scripts/Makefile.lib

# find all modules listed in modules.order
modules := $(sort $(shell cat $(MODORDER)))

__modfinal: $(modules)
	@:

# modname and part-of-module are set to make c_flags define proper module flags
modname = $(notdir $(@:.mod.o=))
part-of-module = y

quiet_cmd_cc_o_c = CC [M]  $@
      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<

%.mod.o: %.mod.c FORCE
	$(call if_changed_dep,cc_o_c)

ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)

quiet_cmd_ld_ko_o = LD [M]  $@
      cmd_ld_ko_o =                                                     \
	$(LD) -r $(KBUILD_LDFLAGS)					\
		$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)		\
		$(addprefix -T , $(KBUILD_LDS_MODULE))			\
		-o $@ $(filter %.o, $^);				\
	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)

$(modules): %.ko: %.o %.mod.o $(KBUILD_LDS_MODULE) FORCE
	+$(call if_changed,ld_ko_o)

targets += $(modules) $(modules:.ko=.mod.o)

# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------

PHONY += FORCE
FORCE:

# Read all saved command lines and dependencies for the $(targets) we
# may be building above, using $(if_changed{,_dep}). As an
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.

existing-targets := $(wildcard $(sort $(targets)))

-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)

.PHONY: $(PHONY)
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