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: 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>

diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 2d786072ed0d03efa53b13dd83f594e791a75f11..a4f5a436777f0bc120eb4569085bfe9ec099507d 100644 (file)
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -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 @@ again:
        }
        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;
 }