diff mbox series

[bpf-next,v2] bpftool: adding support for BTF program names

Message ID 20220119100255.1068997-1-ramasha@fb.com (mailing list archive)
State Accepted
Commit b662000aff84f2ca9660db15e5f8ac926681df27
Delegated to: BPF
Headers show
Series [bpf-next,v2] bpftool: adding support for BTF program names | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 9 maintainers not CCed: liujian56@huawei.com quentin@isovalent.com kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com davemarchevsky@fb.com yhs@fb.com netdev@vger.kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 170 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next success VM_Test
bpf/vmtest-bpf-next-PR success PR summary

Commit Message

Raman Shukhau Jan. 19, 2022, 10:02 a.m. UTC 
`bpftool prog list` and other bpftool subcommands that show
BPF program names currently get them from bpf_prog_info.name.
That field is limited to 16 (BPF_OBJ_NAME_LEN) chars which leads
to truncated names since many progs have much longer names.

The idea of this change is to improve all bpftool commands that
output prog name so that bpftool uses info from BTF to print
program names if available.

It tries bpf_prog_info.name first and fall back to btf only if
the name is suspected to be truncated (has 15 chars length).

Right now `bpftool p show id <id>` returns capped prog name

<id>: kprobe  name example_cap_cap  tag 712e...
...

With this change it would return

<id>: kprobe  name example_cap_capable  tag 712e...
...

Note, other commands that print prog names (e.g. "bpftool
cgroup tree") are also addressed in this change.

Signed-off-by: Raman Shukhau <ramasha@fb.com>
---
 tools/bpf/bpftool/cgroup.c |  6 ++++--
 tools/bpf/bpftool/common.c | 44 ++++++++++++++++++++++++++++++++++++++
 tools/bpf/bpftool/main.h   |  4 ++++
 tools/bpf/bpftool/prog.c   | 28 +++++++++++++++---------
 4 files changed, 70 insertions(+), 12 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Jan. 19, 2022, 6:20 p.m. UTC | #1 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Wed, 19 Jan 2022 02:02:55 -0800 you wrote:
> `bpftool prog list` and other bpftool subcommands that show
> BPF program names currently get them from bpf_prog_info.name.
> That field is limited to 16 (BPF_OBJ_NAME_LEN) chars which leads
> to truncated names since many progs have much longer names.
> 
> The idea of this change is to improve all bpftool commands that
> output prog name so that bpftool uses info from BTF to print
> program names if available.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v2] bpftool: adding support for BTF program names
    https://git.kernel.org/bpf/bpf-next/c/b662000aff84

You are awesome, thank you!
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index 3571a281c43f..effe136119d7 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -50,6 +50,7 @@  static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 			 const char *attach_flags_str,
 			 int level)
 {
+	char prog_name[MAX_PROG_FULL_NAME];
 	struct bpf_prog_info info = {};
 	__u32 info_len = sizeof(info);
 	int prog_fd;
@@ -63,6 +64,7 @@  static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 		return -1;
 	}
 
+	get_prog_full_name(&info, prog_fd, prog_name, sizeof(prog_name));
 	if (json_output) {
 		jsonw_start_object(json_wtr);
 		jsonw_uint_field(json_wtr, "id", info.id);
@@ -73,7 +75,7 @@  static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 			jsonw_uint_field(json_wtr, "attach_type", attach_type);
 		jsonw_string_field(json_wtr, "attach_flags",
 				   attach_flags_str);
-		jsonw_string_field(json_wtr, "name", info.name);
+		jsonw_string_field(json_wtr, "name", prog_name);
 		jsonw_end_object(json_wtr);
 	} else {
 		printf("%s%-8u ", level ? "    " : "", info.id);
@@ -81,7 +83,7 @@  static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 			printf("%-15s", attach_type_name[attach_type]);
 		else
 			printf("type %-10u", attach_type);
-		printf(" %-15s %-15s\n", attach_flags_str, info.name);
+		printf(" %-15s %-15s\n", attach_flags_str, prog_name);
 	}
 
 	close(prog_fd);
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index fa8eb8134344..111dff809c7b 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -24,6 +24,7 @@ 
 #include <bpf/bpf.h>
 #include <bpf/hashmap.h>
 #include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
+#include <bpf/btf.h>
 
 #include "main.h"
 
@@ -304,6 +305,49 @@  const char *get_fd_type_name(enum bpf_obj_type type)
 	return names[type];
 }
 
+void get_prog_full_name(const struct bpf_prog_info *prog_info, int prog_fd,
+			char *name_buff, size_t buff_len)
+{
+	const char *prog_name = prog_info->name;
+	const struct btf_type *func_type;
+	const struct bpf_func_info finfo;
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
+	struct btf *prog_btf = NULL;
+
+	if (buff_len <= BPF_OBJ_NAME_LEN ||
+	    strlen(prog_info->name) < BPF_OBJ_NAME_LEN - 1)
+		goto copy_name;
+
+	if (!prog_info->btf_id || prog_info->nr_func_info == 0)
+		goto copy_name;
+
+	info.nr_func_info = 1;
+	info.func_info_rec_size = prog_info->func_info_rec_size;
+	if (info.func_info_rec_size > sizeof(finfo))
+		info.func_info_rec_size = sizeof(finfo);
+	info.func_info = ptr_to_u64(&finfo);
+
+	if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len))
+		goto copy_name;
+
+	prog_btf = btf__load_from_kernel_by_id(info.btf_id);
+	if (!prog_btf)
+		goto copy_name;
+
+	func_type = btf__type_by_id(prog_btf, finfo.type_id);
+	if (!func_type || !btf_is_func(func_type))
+		goto copy_name;
+
+	prog_name = btf__name_by_offset(prog_btf, func_type->name_off);
+
+copy_name:
+	snprintf(name_buff, buff_len, "%s", prog_name);
+
+	if (prog_btf)
+		btf__free(prog_btf);
+}
+
 int get_fd_type(int fd)
 {
 	char path[PATH_MAX];
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 8d76d937a62b..0c3840596b5a 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -140,6 +140,10 @@  struct cmd {
 int cmd_select(const struct cmd *cmds, int argc, char **argv,
 	       int (*help)(int argc, char **argv));
 
+#define MAX_PROG_FULL_NAME 128
+void get_prog_full_name(const struct bpf_prog_info *prog_info, int prog_fd,
+			char *name_buff, size_t buff_len);
+
 int get_fd_type(int fd);
 const char *get_fd_type_name(enum bpf_obj_type type);
 char *get_fdinfo(int fd, const char *key);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 33ca834d5f51..cf935c63e6f5 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -424,8 +424,10 @@  static void show_prog_metadata(int fd, __u32 num_maps)
 	free(value);
 }
 
-static void print_prog_header_json(struct bpf_prog_info *info)
+static void print_prog_header_json(struct bpf_prog_info *info, int fd)
 {
+	char prog_name[MAX_PROG_FULL_NAME];
+
 	jsonw_uint_field(json_wtr, "id", info->id);
 	if (info->type < ARRAY_SIZE(prog_type_name))
 		jsonw_string_field(json_wtr, "type",
@@ -433,8 +435,10 @@  static void print_prog_header_json(struct bpf_prog_info *info)
 	else
 		jsonw_uint_field(json_wtr, "type", info->type);
 
-	if (*info->name)
-		jsonw_string_field(json_wtr, "name", info->name);
+	if (*info->name) {
+		get_prog_full_name(info, fd, prog_name, sizeof(prog_name));
+		jsonw_string_field(json_wtr, "name", prog_name);
+	}
 
 	jsonw_name(json_wtr, "tag");
 	jsonw_printf(json_wtr, "\"" BPF_TAG_FMT "\"",
@@ -455,7 +459,7 @@  static void print_prog_json(struct bpf_prog_info *info, int fd)
 	char *memlock;
 
 	jsonw_start_object(json_wtr);
-	print_prog_header_json(info);
+	print_prog_header_json(info, fd);
 	print_dev_json(info->ifindex, info->netns_dev, info->netns_ino);
 
 	if (info->load_time) {
@@ -507,16 +511,20 @@  static void print_prog_json(struct bpf_prog_info *info, int fd)
 	jsonw_end_object(json_wtr);
 }
 
-static void print_prog_header_plain(struct bpf_prog_info *info)
+static void print_prog_header_plain(struct bpf_prog_info *info, int fd)
 {
+	char prog_name[MAX_PROG_FULL_NAME];
+
 	printf("%u: ", info->id);
 	if (info->type < ARRAY_SIZE(prog_type_name))
 		printf("%s  ", prog_type_name[info->type]);
 	else
 		printf("type %u  ", info->type);
 
-	if (*info->name)
-		printf("name %s  ", info->name);
+	if (*info->name) {
+		get_prog_full_name(info, fd, prog_name, sizeof(prog_name));
+		printf("name %s  ", prog_name);
+	}
 
 	printf("tag ");
 	fprint_hex(stdout, info->tag, BPF_TAG_SIZE, "");
@@ -534,7 +542,7 @@  static void print_prog_plain(struct bpf_prog_info *info, int fd)
 {
 	char *memlock;
 
-	print_prog_header_plain(info);
+	print_prog_header_plain(info, fd);
 
 	if (info->load_time) {
 		char buf[32];
@@ -972,10 +980,10 @@  static int do_dump(int argc, char **argv)
 
 		if (json_output && nb_fds > 1) {
 			jsonw_start_object(json_wtr);	/* prog object */
-			print_prog_header_json(&info);
+			print_prog_header_json(&info, fds[i]);
 			jsonw_name(json_wtr, "insns");
 		} else if (nb_fds > 1) {
-			print_prog_header_plain(&info);
+			print_prog_header_plain(&info, fds[i]);
 		}
 
 		err = prog_dump(&info, mode, filepath, opcodes, visual, linum);