Re: [PATCH bpf-next 5/6] selftests/bpf: test BPF_MAP_DUMP command on a bpf hashmap

From: Song Liu
Date: Wed Jul 24 2019 - 17:58:53 EST


On Wed, Jul 24, 2019 at 10:10 AM Brian Vazquez <brianvv@xxxxxxxxxx> wrote:
>
> This tests exercise the new command on a bpf hashmap and make sure it
> works as expected.
>
> Signed-off-by: Brian Vazquez <brianvv@xxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/test_maps.c | 83 ++++++++++++++++++++++++-
> 1 file changed, 81 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
> index 5443b9bd75ed7..f7ab401399d40 100644
> --- a/tools/testing/selftests/bpf/test_maps.c
> +++ b/tools/testing/selftests/bpf/test_maps.c
> @@ -309,6 +309,86 @@ static void test_hashmap_walk(unsigned int task, void *data)
> close(fd);
> }
>
> +static void test_hashmap_dump(void)
> +{
> + int fd, i, max_entries = 5;

5 is too small for map_dump.

> + uint64_t keys[max_entries], values[max_entries];
> + uint64_t key, value, next_key, prev_key;
> + bool next_key_valid = true;
> + void *buf, *elem;
> + u32 buf_len;
> + const int elem_size = sizeof(key) + sizeof(value);
> +
> + fd = helper_fill_hashmap(max_entries);
> +
> + // Get the elements in the hashmap, and store them in that order

Please use /* */ instead of //.

> + assert(bpf_map_get_next_key(fd, NULL, &key) == 0);
> + i = 0;
> + keys[i] = key;
> + for (i = 1; next_key_valid; i++) {
> + next_key_valid = bpf_map_get_next_key(fd, &key, &next_key) == 0;
> + assert(bpf_map_lookup_elem(fd, &key, &values[i - 1]) == 0);
> + keys[i-1] = key;
> + key = next_key;
> + }
> +
> + // Alloc memory for the whole table
> + buf = malloc(elem_size * max_entries);
> + assert(buf != NULL);
> +
> + // Check that buf_len < elem_size returns EINVAL
> + buf_len = elem_size-1;
> + errno = 0;
> + assert(bpf_map_dump(fd, NULL, buf, &buf_len) == -1 && errno == EINVAL);
> +
> + // Check that it returns the first two elements
> + errno = 0;
> + buf_len = elem_size * 2;
> + i = 0;
> + assert(bpf_map_dump(fd, NULL, buf, &buf_len) == 0 &&
> + buf_len == 2*elem_size);
> + elem = buf;
> + assert((*(uint64_t *)elem) == keys[i] &&
> + (*(uint64_t *)(elem + sizeof(key))) == values[i]);
> + elem = buf + elem_size;
> + i++;
> + assert((*(uint64_t *)elem) == keys[i] &&
> + (*(uint64_t *)(elem + sizeof(key))) == values[i]);
> + i++;
> +
> + /* Check that prev_key contains key from last_elem retrieved in previous
> + * call
> + */
> + prev_key = *((uint64_t *)elem);
> + assert(bpf_map_dump(fd, &prev_key, buf, &buf_len) == 0 &&
> + buf_len == elem_size*2);
> + elem = buf;
> + assert((*(uint64_t *)elem) == keys[i] &&
> + (*(uint64_t *)(elem + sizeof(key))) == values[i]);
> + elem = buf + elem_size;
> + i++;
> + assert((*(uint64_t *)elem) == keys[i] &&
> + (*(uint64_t *)(elem + sizeof(key))) == values[i]);
> + i++;
> + assert(prev_key == (*(uint64_t *)elem));
> +
> + /* Continue reading from map and verify buf_len only contains 1 element
> + * even though buf_len is 2 elem_size and it returns err = 0.
> + */
> + assert(bpf_map_dump(fd, &prev_key, buf, &buf_len) == 0 &&
> + buf_len == elem_size);
> + elem = buf;
> + assert((*(uint64_t *)elem) == keys[i] &&
> + (*(uint64_t *)(elem + sizeof(key))) == values[i]);
> +
> + // Verify there's no more entries and err = ENOENT
> + assert(bpf_map_dump(fd, &prev_key, buf, &buf_len) == -1 &&
> + errno == ENOENT);
> +
> + free(buf);
> + close(fd);
> +}
> +
> static void test_hashmap_zero_seed(void)
> {
> int i, first, second, old_flags;
> @@ -1677,6 +1757,7 @@ static void run_all_tests(void)
> test_hashmap_percpu(0, NULL);
> test_hashmap_walk(0, NULL);
> test_hashmap_zero_seed();
> + test_hashmap_dump();
>
> test_arraymap(0, NULL);
> test_arraymap_percpu(0, NULL);
> @@ -1714,11 +1795,9 @@ int main(void)
>
> map_flags = BPF_F_NO_PREALLOC;
> run_all_tests();
> -
> #define CALL
> #include <map_tests/tests.h>
> #undef CALL
> -
> printf("test_maps: OK, %d SKIPPED\n", skips);
> return 0;
> }
> --
> 2.22.0.657.g960e92d24f-goog
>