selftests/bpf: Test bpf_link's get_next_id, get_fd_by_id, and get_obj_info

Extend bpf_obj_id selftest to verify bpf_link's observability APIs.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-7-andriin@fb.com

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c b/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c
index f100298..7afa416 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c
@@ -1,26 +1,30 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <test_progs.h>
 
+#define nr_iters 2
+
 void test_bpf_obj_id(void)
 {
        const __u64 array_magic_value = 0xfaceb00c;
        const __u32 array_key = 0;
-       const int nr_iters = 2;
        const char *file = "./test_obj_id.o";
        const char *expected_prog_name = "test_obj_id";
        const char *expected_map_name = "test_map_id";
        const __u64 nsec_per_sec = 1000000000;
 
-       struct bpf_object *objs[nr_iters];
+       struct bpf_object *objs[nr_iters] = {};
+       struct bpf_link *links[nr_iters] = {};
+       struct bpf_program *prog;
        int prog_fds[nr_iters], map_fds[nr_iters];
        /* +1 to test for the info_len returned by kernel */
        struct bpf_prog_info prog_infos[nr_iters + 1];
        struct bpf_map_info map_infos[nr_iters + 1];
+       struct bpf_link_info link_infos[nr_iters + 1];
        /* Each prog only uses one map. +1 to test nr_map_ids
         * returned by kernel.
         */
        __u32 map_ids[nr_iters + 1];
-       char jited_insns[128], xlated_insns[128], zeros[128];
+       char jited_insns[128], xlated_insns[128], zeros[128], tp_name[128];
        __u32 i, next_id, info_len, nr_id_found, duration = 0;
        struct timespec real_time_ts, boot_time_ts;
        int err = 0;
@@ -36,14 +40,15 @@ void test_bpf_obj_id(void)
        CHECK(err >= 0 || errno != ENOENT,
              "get-fd-by-notexist-map-id", "err %d errno %d\n", err, errno);
 
-       for (i = 0; i < nr_iters; i++)
-               objs[i] = NULL;
+       err = bpf_link_get_fd_by_id(0);
+       CHECK(err >= 0 || errno != ENOENT,
+             "get-fd-by-notexist-link-id", "err %d errno %d\n", err, errno);
 
        /* Check bpf_obj_get_info_by_fd() */
        bzero(zeros, sizeof(zeros));
        for (i = 0; i < nr_iters; i++) {
                now = time(NULL);
-               err = bpf_prog_load(file, BPF_PROG_TYPE_SOCKET_FILTER,
+               err = bpf_prog_load(file, BPF_PROG_TYPE_RAW_TRACEPOINT,
                                    &objs[i], &prog_fds[i]);
                /* test_obj_id.o is a dumb prog. It should never fail
                 * to load.
@@ -60,6 +65,17 @@ void test_bpf_obj_id(void)
                if (CHECK_FAIL(err))
                        goto done;
 
+               prog = bpf_object__find_program_by_title(objs[i],
+                                                        "raw_tp/sys_enter");
+               if (CHECK_FAIL(!prog))
+                       goto done;
+               links[i] = bpf_program__attach(prog);
+               err = libbpf_get_error(links[i]);
+               if (CHECK(err, "prog_attach", "prog #%d, err %d\n", i, err)) {
+                       links[i] = NULL;
+                       goto done;
+               }
+
                /* Check getting map info */
                info_len = sizeof(struct bpf_map_info) * 2;
                bzero(&map_infos[i], info_len);
@@ -107,7 +123,7 @@ void test_bpf_obj_id(void)
                load_time = (real_time_ts.tv_sec - boot_time_ts.tv_sec)
                        + (prog_infos[i].load_time / nsec_per_sec);
                if (CHECK(err ||
-                         prog_infos[i].type != BPF_PROG_TYPE_SOCKET_FILTER ||
+                         prog_infos[i].type != BPF_PROG_TYPE_RAW_TRACEPOINT ||
                          info_len != sizeof(struct bpf_prog_info) ||
                          (env.jit_enabled && !prog_infos[i].jited_prog_len) ||
                          (env.jit_enabled &&
@@ -120,7 +136,11 @@ void test_bpf_obj_id(void)
                          *(int *)(long)prog_infos[i].map_ids != map_infos[i].id ||
                          strcmp((char *)prog_infos[i].name, expected_prog_name),
                          "get-prog-info(fd)",
-                         "err %d errno %d i %d type %d(%d) info_len %u(%zu) jit_enabled %d jited_prog_len %u xlated_prog_len %u jited_prog %d xlated_prog %d load_time %lu(%lu) uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) name %s(%s)\n",
+                         "err %d errno %d i %d type %d(%d) info_len %u(%zu) "
+                         "jit_enabled %d jited_prog_len %u xlated_prog_len %u "
+                         "jited_prog %d xlated_prog %d load_time %lu(%lu) "
+                         "uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) "
+                         "name %s(%s)\n",
                          err, errno, i,
                          prog_infos[i].type, BPF_PROG_TYPE_SOCKET_FILTER,
                          info_len, sizeof(struct bpf_prog_info),
@@ -135,6 +155,33 @@ void test_bpf_obj_id(void)
                          *(int *)(long)prog_infos[i].map_ids, map_infos[i].id,
                          prog_infos[i].name, expected_prog_name))
                        goto done;
+
+               /* Check getting link info */
+               info_len = sizeof(struct bpf_link_info) * 2;
+               bzero(&link_infos[i], info_len);
+               link_infos[i].raw_tracepoint.tp_name = (__u64)&tp_name;
+               link_infos[i].raw_tracepoint.tp_name_len = sizeof(tp_name);
+               err = bpf_obj_get_info_by_fd(bpf_link__fd(links[i]),
+                                            &link_infos[i], &info_len);
+               if (CHECK(err ||
+                         link_infos[i].type != BPF_LINK_TYPE_RAW_TRACEPOINT ||
+                         link_infos[i].prog_id != prog_infos[i].id ||
+                         link_infos[i].raw_tracepoint.tp_name != (__u64)&tp_name ||
+                         strcmp((char *)link_infos[i].raw_tracepoint.tp_name,
+                                "sys_enter") ||
+                         info_len != sizeof(struct bpf_link_info),
+                         "get-link-info(fd)",
+                         "err %d errno %d info_len %u(%zu) type %d(%d) id %d "
+                         "prog_id %d (%d) tp_name %s(%s)\n",
+                         err, errno,
+                         info_len, sizeof(struct bpf_link_info),
+                         link_infos[i].type, BPF_LINK_TYPE_RAW_TRACEPOINT,
+                         link_infos[i].id,
+                         link_infos[i].prog_id, prog_infos[i].id,
+                         (char *)link_infos[i].raw_tracepoint.tp_name,
+                         "sys_enter"))
+                       goto done;
+
        }
 
        /* Check bpf_prog_get_next_id() */
@@ -247,7 +294,52 @@ void test_bpf_obj_id(void)
              "nr_id_found %u(%u)\n",
              nr_id_found, nr_iters);
 
+       /* Check bpf_link_get_next_id() */
+       nr_id_found = 0;
+       next_id = 0;
+       while (!bpf_link_get_next_id(next_id, &next_id)) {
+               struct bpf_link_info link_info;
+               int link_fd, cmp_res;
+
+               info_len = sizeof(link_info);
+               memset(&link_info, 0, info_len);
+
+               link_fd = bpf_link_get_fd_by_id(next_id);
+               if (link_fd < 0 && errno == ENOENT)
+                       /* The bpf_link is in the dead row */
+                       continue;
+               if (CHECK(link_fd < 0, "get-link-fd(next_id)",
+                         "link_fd %d next_id %u errno %d\n",
+                         link_fd, next_id, errno))
+                       break;
+
+               for (i = 0; i < nr_iters; i++)
+                       if (link_infos[i].id == next_id)
+                               break;
+
+               if (i == nr_iters)
+                       continue;
+
+               nr_id_found++;
+
+               err = bpf_obj_get_info_by_fd(link_fd, &link_info, &info_len);
+               cmp_res = memcmp(&link_info, &link_infos[i],
+                               offsetof(struct bpf_link_info, raw_tracepoint));
+               CHECK(err || info_len != sizeof(link_info) || cmp_res,
+                     "check get-link-info(next_id->fd)",
+                     "err %d errno %d info_len %u(%zu) memcmp %d\n",
+                     err, errno, info_len, sizeof(struct bpf_link_info),
+                     cmp_res);
+
+               close(link_fd);
+       }
+       CHECK(nr_id_found != nr_iters,
+             "check total link id found by get_next_id",
+             "nr_id_found %u(%u)\n", nr_id_found, nr_iters);
+
 done:
-       for (i = 0; i < nr_iters; i++)
+       for (i = 0; i < nr_iters; i++) {
+               bpf_link__destroy(links[i]);
                bpf_object__close(objs[i]);
+       }
 }

diff --git a/tools/testing/selftests/bpf/progs/test_obj_id.c b/tools/testing/selftests/bpf/progs/test_obj_id.c
index 98b9de2..ded71b3 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_obj_id.c
+++ b/tools/testing/selftests/bpf/progs/test_obj_id.c
@@ -3,16 +3,8 @@
  */
 #include <stddef.h>
 #include <linux/bpf.h>
-#include <linux/pkt_cls.h>
 #include <bpf/bpf_helpers.h>
 
-/* It is a dumb bpf program such that it must have no
- * issue to be loaded since testing the verifier is
- * not the focus here.
- */
-
-int _version SEC("version") = 1;
-
 struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
@@ -20,13 +12,13 @@ struct {
        __type(value, __u64);
 } test_map_id SEC(".maps");
 
-SEC("test_obj_id_dummy")
-int test_obj_id(struct __sk_buff *skb)
+SEC("raw_tp/sys_enter")
+int test_obj_id(void *ctx)
 {
        __u32 key = 0;
        __u64 *value;
 
        value = bpf_map_lookup_elem(&test_map_id, &key);
 
-       return TC_ACT_OK;
+       return 0;
 }