[PATCH bpf-next 1/2] selftests/bpf: validate skeleton gen handles skipped fields

[PATCH bpf-next 1/2] selftests/bpf: validate skeleton gen handles skipped fields

[Andrii Nakryiko]

Adjust static_linked selftests to test a mix of global and static variables
and their handling of bpftool's skeleton generation code.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/static_linked.c  | 4 ++--
 tools/testing/selftests/bpf/progs/linked_maps1.c        | 2 +-
 tools/testing/selftests/bpf/progs/test_static_linked1.c | 2 +-
 tools/testing/selftests/bpf/progs/test_static_linked2.c | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/static_linked.c b/tools/testing/selftests/bpf/prog_tests/static_linked.c
index ab6acbaf9d8c..5c4e3014e063 100644
--- a/tools/testing/selftests/bpf/prog_tests/static_linked.c
+++ b/tools/testing/selftests/bpf/prog_tests/static_linked.c
@@ -27,8 +27,8 @@ void test_static_linked(void)
 	/* trigger */
 	usleep(1);
 
-	ASSERT_EQ(skel->bss->var1, 1 * 2 + 2 + 3, "var1");
-	ASSERT_EQ(skel->bss->var2, 4 * 3 + 5 + 6, "var2");
+	ASSERT_EQ(skel->data->var1, 1 * 2 + 2 + 3, "var1");
+	ASSERT_EQ(skel->data->var2, 4 * 3 + 5 + 6, "var2");
 
 cleanup:
 	test_static_linked__destroy(skel);
diff --git a/tools/testing/selftests/bpf/progs/linked_maps1.c b/tools/testing/selftests/bpf/progs/linked_maps1.c
index 52291515cc72..00bf1ca95986 100644
--- a/tools/testing/selftests/bpf/progs/linked_maps1.c
+++ b/tools/testing/selftests/bpf/progs/linked_maps1.c
@@ -75,7 +75,7 @@ int BPF_PROG(handler_exit1)
 	val = bpf_map_lookup_elem(&map_weak, &key);
 	if (val)
 		output_weak1 = *val;
-	
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/bpf/progs/test_static_linked1.c b/tools/testing/selftests/bpf/progs/test_static_linked1.c
index cae304045d9c..4f0b612e1661 100644
--- a/tools/testing/selftests/bpf/progs/test_static_linked1.c
+++ b/tools/testing/selftests/bpf/progs/test_static_linked1.c
@@ -7,7 +7,7 @@
 /* 8-byte aligned .data */
 static volatile long static_var1 = 2;
 static volatile int static_var2 = 3;
-int var1 = 0;
+int var1 = -1;
 /* 4-byte aligned .rodata */
 const volatile int rovar1;
 
diff --git a/tools/testing/selftests/bpf/progs/test_static_linked2.c b/tools/testing/selftests/bpf/progs/test_static_linked2.c
index c54c4e865ed8..766ebd502a60 100644
--- a/tools/testing/selftests/bpf/progs/test_static_linked2.c
+++ b/tools/testing/selftests/bpf/progs/test_static_linked2.c
@@ -7,7 +7,7 @@
 /* 4-byte aligned .data */
 static volatile int static_var1 = 5;
 static volatile int static_var2 = 6;
-int var2 = 0;
+int var2 = -1;
 /* 8-byte aligned .rodata */
 const volatile long rovar2;
 
-- 
2.30.2

[PATCH bpf-next 2/2] libbpf: reject static maps

[Andrii Nakryiko]

Static maps never really worked with libbpf, because all such maps were always
silently resolved to the very first map. Detect static maps (both legacy and
BTF-defined) and report user-friendly error.

Tested locally by switching few maps (legacy and BTF-defined) in selftests to
static ones and verifying that now libbpf rejects them loudly.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/lib/bpf/libbpf.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b8cf93fa1b4d..ac5ab903d42b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1795,7 +1795,6 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 	if (!symbols)
 		return -EINVAL;
 
-
 	scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
 	data = elf_sec_data(obj, scn);
 	if (!scn || !data) {
@@ -1848,6 +1847,7 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 		if (IS_ERR(map))
 			return PTR_ERR(map);
 
+
 		map_name = elf_sym_str(obj, sym.st_name);
 		if (!map_name) {
 			pr_warn("failed to get map #%d name sym string for obj %s\n",
@@ -1855,6 +1855,12 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 			return -LIBBPF_ERRNO__FORMAT;
 		}
 
+		if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
+		    || GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
+			pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
+			return -ENOTSUP;
+		}
+
 		map->libbpf_type = LIBBPF_MAP_UNSPEC;
 		map->sec_idx = sym.st_shndx;
 		map->sec_offset = sym.st_value;
@@ -2262,6 +2268,16 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
 		pr_debug("map '%s': found inner map definition.\n", map->name);
 }
 
+static const char *btf_var_linkage_str(__u32 linkage)
+{
+	switch (linkage) {
+	case BTF_VAR_STATIC: return "static";
+	case BTF_VAR_GLOBAL_ALLOCATED: return "global";
+	case BTF_VAR_GLOBAL_EXTERN: return "extern";
+	default: return "unknown";
+	}
+}
+
 static int bpf_object__init_user_btf_map(struct bpf_object *obj,
 					 const struct btf_type *sec,
 					 int var_idx, int sec_idx,
@@ -2294,10 +2310,9 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
 			map_name, btf_kind_str(var));
 		return -EINVAL;
 	}
-	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
-	    var_extra->linkage != BTF_VAR_STATIC) {
-		pr_warn("map '%s': unsupported var linkage %u.\n",
-			map_name, var_extra->linkage);
+	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
+		pr_warn("map '%s': unsupported map linkage %s.\n",
+			map_name, btf_var_linkage_str(var_extra->linkage));
 		return -EOPNOTSUPP;
 	}
 
-- 
2.30.2