Commit edd7f49b authored by Yafang Shao's avatar Yafang Shao Committed by Alexei Starovoitov
Browse files

bpftool: Show kprobe_multi link info 



Show the already expose kprobe_multi link info in bpftool. The result as
follows,

$ tools/bpf/bpftool/bpftool link show
91: kprobe_multi  prog 244
        kprobe.multi  func_cnt 7
        addr             func [module]
        ffffffff98c44f20 schedule_timeout_interruptible
        ffffffff98c44f60 schedule_timeout_killable
        ffffffff98c44fa0 schedule_timeout_uninterruptible
        ffffffff98c44fe0 schedule_timeout_idle
        ffffffffc075b8d0 xfs_trans_get_efd [xfs]
        ffffffffc0768a10 xfs_trans_get_buf_map [xfs]
        ffffffffc076c320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(188367)
92: kprobe_multi  prog 244
        kretprobe.multi  func_cnt 7
        addr             func [module]
        ffffffff98c44f20 schedule_timeout_interruptible
        ffffffff98c44f60 schedule_timeout_killable
        ffffffff98c44fa0 schedule_timeout_uninterruptible
        ffffffff98c44fe0 schedule_timeout_idle
        ffffffffc075b8d0 xfs_trans_get_efd [xfs]
        ffffffffc0768a10 xfs_trans_get_buf_map [xfs]
        ffffffffc076c320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(188367)

$ tools/bpf/bpftool/bpftool link show -j
[{"id":91,"type":"kprobe_multi","prog_id":244,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744071977586464,"func":"schedule_timeout_interruptible","module":null},{"addr":18446744071977586528,"func":"schedule_timeout_killable","module":null},{"addr":18446744071977586592,"func":"schedule_timeout_uninterruptible","module":null},{"addr":18446744071977586656,"func":"schedule_timeout_idle","module":null},{"addr":18446744072643524816,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072643578384,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072643592992,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":188367,"comm":"kprobe_multi"}]},{"id":92,"type":"kprobe_multi","prog_id":244,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744071977586464,"func":"schedule_timeout_interruptible","module":null},{"addr":18446744071977586528,"func":"schedule_timeout_killable","module":null},{"addr":18446744071977586592,"func":"schedule_timeout_uninterruptible","module":null},{"addr":18446744071977586656,"func":"schedule_timeout_idle","module":null},{"addr":18446744072643524816,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072643578384,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072643592992,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":188367,"comm":"kprobe_multi"}]}]

When kptr_restrict is 2, the result is,

$ tools/bpf/bpftool/bpftool link show
91: kprobe_multi  prog 244
        kprobe.multi  func_cnt 7
92: kprobe_multi  prog 244
        kretprobe.multi  func_cnt 7

Signed-off-by: default avatarYafang Shao <laoar.shao@gmail.com>
Reviewed-by: default avatarQuentin Monnet <quentin@isovalent.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-4-laoar.shao@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent dc651944

tools/bpf/bpftool/link.c

+115 −3
Original line number Diff line number Diff line
@@ -14,8 +14,10 @@ 


#include "json_writer.h"

#include "main.h"

#include "xlated_dumper.h"



static struct hashmap *link_table;

static struct dump_data dd;



static int link_parse_fd(int *argc, char ***argv)

{
@@ -166,6 +168,50 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info) 
	return err;

}



static int cmp_u64(const void *A, const void *B)

{

	const __u64 *a = A, *b = B;



	return *a - *b;

}



static void

show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)

{

	__u32 i, j = 0;

	__u64 *addrs;



	jsonw_bool_field(json_wtr, "retprobe",

			 info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);

	jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);

	jsonw_name(json_wtr, "funcs");

	jsonw_start_array(json_wtr);

	addrs = u64_to_ptr(info->kprobe_multi.addrs);

	qsort(addrs, info->kprobe_multi.count, sizeof(addrs[0]), cmp_u64);



	/* Load it once for all. */

	if (!dd.sym_count)

		kernel_syms_load(&dd);

	for (i = 0; i < dd.sym_count; i++) {

		if (dd.sym_mapping[i].address != addrs[j])

			continue;

		jsonw_start_object(json_wtr);

		jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);

		jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);

		/* Print null if it is vmlinux */

		if (dd.sym_mapping[i].module[0] == '\0') {

			jsonw_name(json_wtr, "module");

			jsonw_null(json_wtr);

		} else {

			jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);

		}

		jsonw_end_object(json_wtr);

		if (j++ == info->kprobe_multi.count)

			break;

	}

	jsonw_end_array(json_wtr);

}



static int show_link_close_json(int fd, struct bpf_link_info *info)

{

	struct bpf_prog_info prog_info;
@@ -218,6 +264,9 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) 
		jsonw_uint_field(json_wtr, "map_id",

				 info->struct_ops.map_id);

		break;

	case BPF_LINK_TYPE_KPROBE_MULTI:

		show_kprobe_multi_json(info, json_wtr);

		break;

	default:

		break;

	}
@@ -351,6 +400,44 @@ void netfilter_dump_plain(const struct bpf_link_info *info) 
		printf(" flags 0x%x", info->netfilter.flags);

}



static void show_kprobe_multi_plain(struct bpf_link_info *info)

{

	__u32 i, j = 0;

	__u64 *addrs;



	if (!info->kprobe_multi.count)

		return;



	if (info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN)

		printf("\n\tkretprobe.multi  ");

	else

		printf("\n\tkprobe.multi  ");

	printf("func_cnt %u  ", info->kprobe_multi.count);

	addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);

	qsort(addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);



	/* Load it once for all. */

	if (!dd.sym_count)

		kernel_syms_load(&dd);

	if (!dd.sym_count)

		return;



	printf("\n\t%-16s %s", "addr", "func [module]");

	for (i = 0; i < dd.sym_count; i++) {

		if (dd.sym_mapping[i].address != addrs[j])

			continue;

		printf("\n\t%016lx %s",

		       dd.sym_mapping[i].address, dd.sym_mapping[i].name);

		if (dd.sym_mapping[i].module[0] != '\0')

			printf(" [%s]  ", dd.sym_mapping[i].module);

		else

			printf("  ");



		if (j++ == info->kprobe_multi.count)

			break;

	}

}



static int show_link_close_plain(int fd, struct bpf_link_info *info)

{

	struct bpf_prog_info prog_info;
@@ -396,6 +483,9 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info) 
	case BPF_LINK_TYPE_NETFILTER:

		netfilter_dump_plain(info);

		break;

	case BPF_LINK_TYPE_KPROBE_MULTI:

		show_kprobe_multi_plain(info);

		break;

	default:

		break;

	}
@@ -417,7 +507,9 @@ static int do_show_link(int fd) 
{

	struct bpf_link_info info;

	__u32 len = sizeof(info);

	__u64 *addrs = NULL;

	char buf[256];

	int count;

	int err;



	memset(&info, 0, sizeof(info));
@@ -431,22 +523,38 @@ static int do_show_link(int fd) 
	}

	if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&

	    !info.raw_tracepoint.tp_name) {

		info.raw_tracepoint.tp_name = (unsigned long)&buf;

		info.raw_tracepoint.tp_name = ptr_to_u64(&buf);

		info.raw_tracepoint.tp_name_len = sizeof(buf);

		goto again;

	}

	if (info.type == BPF_LINK_TYPE_ITER &&

	    !info.iter.target_name) {

		info.iter.target_name = (unsigned long)&buf;

		info.iter.target_name = ptr_to_u64(&buf);

		info.iter.target_name_len = sizeof(buf);

		goto again;

	}

	if (info.type == BPF_LINK_TYPE_KPROBE_MULTI &&

	    !info.kprobe_multi.addrs) {

		count = info.kprobe_multi.count;

		if (count) {

			addrs = calloc(count, sizeof(__u64));

			if (!addrs) {

				p_err("mem alloc failed");

				close(fd);

				return -ENOMEM;

			}

			info.kprobe_multi.addrs = ptr_to_u64(addrs);

			goto again;

		}

	}



	if (json_output)

		show_link_close_json(fd, &info);

	else

		show_link_close_plain(fd, &info);



	if (addrs)

		free(addrs);

	close(fd);

	return 0;

}
@@ -471,7 +579,8 @@ static int do_show(int argc, char **argv) 
		fd = link_parse_fd(&argc, &argv);

		if (fd < 0)

			return fd;

		return do_show_link(fd);

		do_show_link(fd);

		goto out;

	}



	if (argc)
@@ -510,6 +619,9 @@ static int do_show(int argc, char **argv) 
	if (show_pinned)

		delete_pinned_obj_table(link_table);



out:

	if (dd.sym_count)

		kernel_syms_destroy(&dd);

	return errno == ENOENT ? 0 : -1;

}