Gustavo A. R. Silva 385bbf7b11 bpf, libbpf: Replace zero-length array with flexible-array ... 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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 7649773293 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200507185057.GA13981@embeddedor		2020-05-11 16:56:47 +02:00
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arraymap.c
bpf_iter.c	bpf: Implement common macros/helpers for target iterators	2020-05-09 17:05:26 -07:00
bpf_lru_list.c
bpf_lru_list.h
bpf_lsm.c
bpf_struct_ops.c
bpf_struct_ops_types.h
btf.c	bpf: Support variable length array in tracing programs	2020-05-09 17:05:27 -07:00
cgroup.c
core.c
cpumap.c
devmap.c
disasm.c
disasm.h
dispatcher.c
hashtab.c
helpers.c
inode.c	bpf: Create file bpf iterator	2020-05-09 17:05:26 -07:00
local_storage.c
lpm_trie.c
Makefile	bpf: Add task and task/file iterator targets	2020-05-09 17:05:26 -07:00
map_in_map.c
map_in_map.h
map_iter.c	bpf: Add bpf_map iterator	2020-05-09 17:05:26 -07:00
offload.c
percpu_freelist.c
percpu_freelist.h
queue_stack_maps.c	bpf, libbpf: Replace zero-length array with flexible-array	2020-05-11 16:56:47 +02:00
reuseport_array.c
stackmap.c
syscall.c	bpf: Add bpf_map iterator	2020-05-09 17:05:26 -07:00
sysfs_btf.c
task_iter.c	bpf: Add task and task/file iterator targets	2020-05-09 17:05:26 -07:00
tnum.c
trampoline.c
verifier.c	bpf: Handle spilled PTR_TO_BTF_ID properly when checking stack_boundary	2020-05-09 17:05:27 -07:00
xskmap.c