selftests/bpf: Fix a compiler warning in local_storage test
Some compilers trigger a warning when tmp_dir_path is allocated
with a fixed size of 64-bytes and used in the following snprintf:
snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",
tmp_dir_path);
warning: ‘/copy_of_rm’ directive output may be truncated writing 11
bytes into a region of size between 1 and 64 [-Wformat-truncation=]
This is because it assumes that tmp_dir_path can be a maximum of 64
bytes long and, therefore, the end-result can get truncated. Fix it by
not using a fixed size in the initialization of tmp_dir_path which
allows the compiler to track actual size of the array better.
Fixes:
2f94ac191846 ("bpf: Update local storage test to check handling of null ptrs")
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210202213730.1906931-1-kpsingh@kernel.org