[PATCH 14/23] tools lib bpf: Fix map offsets in relocation

[PATCH 14/23] tools lib bpf: Fix map offsets in relocation

[Arnaldo Carvalho de Melo]

From: Joe Stringer <joe@ovn.org>

Commit 4708bbda5cb2 ("tools lib bpf: Fix maps resolution") attempted to
fix map resolution by identifying the number of symbols that point to
maps, and using this number to resolve each of the maps.

However, during relocation the original definition of the map size was
still in use. For up to two maps, the calculation was correct if there
was a small difference in size between the map definition in libbpf and
the one that the client library uses. However if the difference was
large, particularly if more than two maps were used in the BPF program,
the relocation would fail.

For example, when using a map definition with size 28, with three maps,
map relocation would count:

    (sym_offset / sizeof(struct bpf_map_def) => map_idx)
    (0 / 16 => 0), ie map_idx = 0
    (28 / 16 => 1), ie map_idx = 1
    (56 / 16 => 3), ie map_idx = 3

So, libbpf reports:

    libbpf: bpf relocation: map_idx 3 large than 2

Fix map relocation by checking the exact offset of maps when doing
relocation.

Signed-off-by: Joe Stringer <joe@ovn.org>
[Allow different map size in an object]
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org
Fixes: 4708bbda5cb2 ("tools lib bpf: Fix maps resolution")
Link: http://lkml.kernel.org/r/20170123011128.26534-2-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 84e6b35da4bd..671d5ad07cf1 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -779,7 +779,7 @@ static int
 bpf_program__collect_reloc(struct bpf_program *prog,
 			   size_t nr_maps, GElf_Shdr *shdr,
 			   Elf_Data *data, Elf_Data *symbols,
-			   int maps_shndx)
+			   int maps_shndx, struct bpf_map *maps)
 {
 	int i, nrels;
 
@@ -829,7 +829,15 @@ bpf_program__collect_reloc(struct bpf_program *prog,
 			return -LIBBPF_ERRNO__RELOC;
 		}
 
-		map_idx = sym.st_value / sizeof(struct bpf_map_def);
+		/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			if (maps[map_idx].offset == sym.st_value) {
+				pr_debug("relocation: find map %zd (%s) for insn %u\n",
+					 map_idx, maps[map_idx].name, insn_idx);
+				break;
+			}
+		}
+
 		if (map_idx >= nr_maps) {
 			pr_warning("bpf relocation: map_idx %d large than %d\n",
 				   (int)map_idx, (int)nr_maps - 1);
@@ -953,7 +961,8 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 		err = bpf_program__collect_reloc(prog, nr_maps,
 						 shdr, data,
 						 obj->efile.symbols,
-						 obj->efile.maps_shndx);
+						 obj->efile.maps_shndx,
+						 obj->maps);
 		if (err)
 			return err;
 	}
-- 
2.9.3

[PATCH 15/23] tools lib bpf: Define prog_type fns with macro

[Arnaldo Carvalho de Melo]

From: Joe Stringer <joe@ovn.org>

Turning this into a macro allows future prog types to be added with a
single line per type.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170123011128.26534-3-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c | 41 ++++++++++++++++-------------------------
 1 file changed, 16 insertions(+), 25 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 671d5ad07cf1..371cb40a2304 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1428,37 +1428,28 @@ static void bpf_program__set_type(struct bpf_program *prog,
 	prog->type = type;
 }
 
-int bpf_program__set_tracepoint(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-	return 0;
-}
-
-int bpf_program__set_kprobe(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
-	return 0;
-}
-
 static bool bpf_program__is_type(struct bpf_program *prog,
 				 enum bpf_prog_type type)
 {
 	return prog ? (prog->type == type) : false;
 }
 
-bool bpf_program__is_tracepoint(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-}
-
-bool bpf_program__is_kprobe(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
-}
+#define BPF_PROG_TYPE_FNS(NAME, TYPE)			\
+int bpf_program__set_##NAME(struct bpf_program *prog)	\
+{							\
+	if (!prog)					\
+		return -EINVAL;				\
+	bpf_program__set_type(prog, TYPE);		\
+	return 0;					\
+}							\
+							\
+bool bpf_program__is_##NAME(struct bpf_program *prog)	\
+{							\
+	return bpf_program__is_type(prog, TYPE);	\
+}							\
+
+BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
+BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
 
 int bpf_map__fd(struct bpf_map *map)
 {
-- 
2.9.3

[PATCH 16/23] tools lib bpf: Add set/is helpers for all prog types

[Arnaldo Carvalho de Melo]

From: Joe Stringer <joe@ovn.org>

These bpf_prog_types were exposed in the uapi but there were no
corresponding functions to set these types for programs in libbpf.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170123011128.26534-4-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c |  5 +++++
 tools/lib/bpf/libbpf.h | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 371cb40a2304..406838fa9c4f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1448,8 +1448,13 @@ bool bpf_program__is_##NAME(struct bpf_program *prog)	\
 	return bpf_program__is_type(prog, TYPE);	\
 }							\
 
+BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
+BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
+BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
+BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
+BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
 int bpf_map__fd(struct bpf_map *map)
 {
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index a5a8b86a06fe..2188ccdc0e2d 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -174,11 +174,21 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n);
 /*
  * Adjust type of bpf program. Default is kprobe.
  */
+int bpf_program__set_socket_filter(struct bpf_program *prog);
 int bpf_program__set_tracepoint(struct bpf_program *prog);
 int bpf_program__set_kprobe(struct bpf_program *prog);
+int bpf_program__set_sched_cls(struct bpf_program *prog);
+int bpf_program__set_sched_act(struct bpf_program *prog);
+int bpf_program__set_xdp(struct bpf_program *prog);
+int bpf_program__set_perf_event(struct bpf_program *prog);
 
+bool bpf_program__is_socket_filter(struct bpf_program *prog);
 bool bpf_program__is_tracepoint(struct bpf_program *prog);
 bool bpf_program__is_kprobe(struct bpf_program *prog);
+bool bpf_program__is_sched_cls(struct bpf_program *prog);
+bool bpf_program__is_sched_act(struct bpf_program *prog);
+bool bpf_program__is_xdp(struct bpf_program *prog);
+bool bpf_program__is_perf_event(struct bpf_program *prog);
 
 /*
  * We don't need __attribute__((packed)) now since it is
-- 
2.9.3

[PATCH 17/23] tools lib bpf: Add libbpf_get_error()

[Arnaldo Carvalho de Melo]

From: Joe Stringer <joe@ovn.org>

This function will turn a libbpf pointer into a standard error code (or
0 if the pointer is valid).

This also allows removal of the dependency on linux/err.h in the public
header file, which causes problems in userspace programs built against
libbpf.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170123011128.26534-5-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c  | 8 ++++++++
 tools/lib/bpf/libbpf.h  | 4 +++-
 tools/perf/tests/llvm.c | 2 +-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 406838fa9c4f..e6cd62b1264b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -28,6 +28,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <asm/unistd.h>
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/bpf.h>
 #include <linux/list.h>
@@ -1542,3 +1543,10 @@ bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
 	}
 	return ERR_PTR(-ENOENT);
 }
+
+long libbpf_get_error(const void *ptr)
+{
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	return 0;
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 2188ccdc0e2d..4014d1ba5e3d 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -22,8 +22,8 @@
 #define __BPF_LIBBPF_H
 
 #include <stdio.h>
+#include <stdint.h>
 #include <stdbool.h>
-#include <linux/err.h>
 #include <sys/types.h>  // for size_t
 
 enum libbpf_errno {
@@ -234,4 +234,6 @@ int bpf_map__set_priv(struct bpf_map *map, void *priv,
 		      bpf_map_clear_priv_t clear_priv);
 void *bpf_map__priv(struct bpf_map *map);
 
+long libbpf_get_error(const void *ptr);
+
 #endif
diff --git a/tools/perf/tests/llvm.c b/tools/perf/tests/llvm.c
index 02a33ebcd992..d357dab72e68 100644
--- a/tools/perf/tests/llvm.c
+++ b/tools/perf/tests/llvm.c
@@ -13,7 +13,7 @@ static int test__bpf_parsing(void *obj_buf, size_t obj_buf_sz)
 	struct bpf_object *obj;
 
 	obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, NULL);
-	if (IS_ERR(obj))
+	if (libbpf_get_error(obj))
 		return TEST_FAIL;
 	bpf_object__close(obj);
 	return TEST_OK;
-- 
2.9.3