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bpftool: Show kprobe_multi link info
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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: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
  • Loading branch information
@laoar @qmonnet
laoar authored and qmonnet committed Aug 29, 2023
1 parent eb8a15a commit b65dc7b
Showing 1 changed file with 115 additions and 3 deletions.
118 changes: 115 additions & 3 deletions src/link.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}
Expand All @@ -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));
Expand All @@ -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;
}
Expand All @@ -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)
Expand Down Expand Up @@ -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;
}

Expand Down

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