Merge branch 'bpftool: Add autoattach for bpf prog load|loadall'

Wang Yufen says:

====================

This patchset add "autoattach" optional for "bpftool prog load(_all)" to support
one-step load-attach-pin_link.

v8 -> v9: fix link leak, and change pathname_concat(specify not just buffer
	  pointer, but also it's size)
v7 -> v8: for the programs not supporting autoattach, fall back to reguler pinning
	  instead of skipping
v6 -> v7: add info msg print and update doc for the skip program
v5 -> v6: skip the programs not supporting auto-attach,
	  and change optional name from "auto_attach" to "autoattach"
v4 -> v5: some formatting nits of doc
v3 -> v4: rename functions, update doc, bash and do_help()
v2 -> v3: switch to extend prog load command instead of extend perf
v2: https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/
v1: https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/
====================

Signed-off-by: Alexei Starovoitov <[email protected]>

1 files changed, 74 insertions, 2 deletions

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index c81362a001ba..10ec29cb4598 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1453,6 +1453,67 @@ get_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
 	return ret;
 }
 
+static int
+auto_attach_program(struct bpf_program *prog, const char *path)
+{
+	struct bpf_link *link;
+	int err;
+
+	link = bpf_program__attach(prog);
+	if (!link) {
+		p_info("Program %s does not support autoattach, falling back to pinning",
+		       bpf_program__name(prog));
+		return bpf_obj_pin(bpf_program__fd(prog), path);
+	}
+
+	err = bpf_link__pin(link, path);
+	bpf_link__destroy(link);
+	return err;
+}
+
+static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name)
+{
+	int len;
+
+	len = snprintf(buf, buf_sz, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if ((size_t)len >= buf_sz)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
+static int
+auto_attach_programs(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	char buf[PATH_MAX];
+	int err;
+
+	bpf_object__for_each_program(prog, obj) {
+		err = pathname_concat(buf, sizeof(buf), path, bpf_program__name(prog));
+		if (err)
+			goto err_unpin_programs;
+
+		err = auto_attach_program(prog, buf);
+		if (err)
+			goto err_unpin_programs;
+	}
+
+	return 0;
+
+err_unpin_programs:
+	while ((prog = bpf_object__prev_program(obj, prog))) {
+		if (pathname_concat(buf, sizeof(buf), path, bpf_program__name(prog)))
+			continue;
+
+		bpf_program__unpin(prog, buf);
+	}
+
+	return err;
+}
+
 static int load_with_options(int argc, char **argv, bool first_prog_only)
 {
 	enum bpf_prog_type common_prog_type = BPF_PROG_TYPE_UNSPEC;
@@ -1464,6 +1525,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 	struct bpf_program *prog = NULL, *pos;
 	unsigned int old_map_fds = 0;
 	const char *pinmaps = NULL;
+	bool auto_attach = false;
 	struct bpf_object *obj;
 	struct bpf_map *map;
 	const char *pinfile;
@@ -1583,6 +1645,9 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 				goto err_free_reuse_maps;
 
 			pinmaps = GET_ARG();
+		} else if (is_prefix(*argv, "autoattach")) {
+			auto_attach = true;
+			NEXT_ARG();
 		} else {
 			p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
 			      *argv);
@@ -1692,14 +1757,20 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 			goto err_close_obj;
 		}
 
-		err = bpf_obj_pin(bpf_program__fd(prog), pinfile);
+		if (auto_attach)
+			err = auto_attach_program(prog, pinfile);
+		else
+			err = bpf_obj_pin(bpf_program__fd(prog), pinfile);
 		if (err) {
 			p_err("failed to pin program %s",
 			      bpf_program__section_name(prog));
 			goto err_close_obj;
 		}
 	} else {
-		err = bpf_object__pin_programs(obj, pinfile);
+		if (auto_attach)
+			err = auto_attach_programs(obj, pinfile);
+		else
+			err = bpf_object__pin_programs(obj, pinfile);
 		if (err) {
 			p_err("failed to pin all programs");
 			goto err_close_obj;
@@ -2338,6 +2409,7 @@ static int do_help(int argc, char **argv)
 		"                         [type TYPE] [dev NAME] \\\n"
 		"                         [map { idx IDX | name NAME } MAP]\\\n"
 		"                         [pinmaps MAP_DIR]\n"
+		"                         [autoattach]\n"
 		"       %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s run PROG \\\n"