Show bpf prog info in the link info.

$ bpftool link
9: tracing_multi  prog 25
        attach_type trace_fsession_multi  btf_obj_id 1  count 2
        prog_id          func_btf_id      addr             cookie           
func [module]
        21               4                ffffffffc080064c 16706819         
target_1 [bpf]
        22               5                ffffffffc08006d4 16706819         
target_2 [bpf]
        pids test_progs(98)

Signed-off-by: Leon Hwang <[email protected]>
---
 include/uapi/linux/bpf.h       |  4 ++-
 kernel/trace/bpf_trace.c       | 25 ++++++++++----
 tools/bpf/bpftool/link.c       | 59 +++++++++++++++++++++++++++-------
 tools/include/uapi/linux/bpf.h |  4 ++-
 4 files changed, 71 insertions(+), 21 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6fa93a6ff54f..e0c8ea5ed2c8 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6890,10 +6890,12 @@ struct bpf_link_info {
                        __u32 attach_type;
                        __u32 count; /* in/out: tracing_multi target count */
                        __u32 btf_obj_id;
-                       __u32 :32;
+                       __u32 tgt_progs:1;
+                       __u32 :31;
                        __aligned_u64 ids;
                        __aligned_u64 addrs;
                        __aligned_u64 cookies;
+                       __aligned_u64 func_btf_ids;
                } tracing_multi;
                struct {
                        __u32 type; /* enum bpf_perf_event_type */
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 80928401830c..d998e7ea563d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3707,15 +3707,16 @@ static void bpf_tracing_multi_link_dealloc(struct 
bpf_link *link)
 static int bpf_tracing_multi_link_fill_link_info(const struct bpf_link *link,
                                                 struct bpf_link_info *info)
 {
+       u32 __user *fids = u64_to_user_ptr(info->tracing_multi.func_btf_ids);
        u64 __user *ucookies = u64_to_user_ptr(info->tracing_multi.cookies);
        u64 __user *uaddrs = u64_to_user_ptr(info->tracing_multi.addrs);
        u32 __user *uids = u64_to_user_ptr(info->tracing_multi.ids);
        struct bpf_tracing_multi_link *tr_link;
        u32 ucount = info->tracing_multi.count;
-       bool has_cookies, show_addrs;
+       bool has_cookies, show_addrs, has_progs;
        int err = 0;
 
-       if ((uids || ucookies || uaddrs) && !ucount)
+       if ((uids || ucookies || uaddrs || fids) && !ucount)
                return -EINVAL;
 
        tr_link = container_of(link, struct bpf_tracing_multi_link, link);
@@ -3723,9 +3724,12 @@ static int bpf_tracing_multi_link_fill_link_info(const 
struct bpf_link *link,
        info->tracing_multi.attach_type = tr_link->link.attach_type;
        info->tracing_multi.count = tr_link->nodes_cnt;
        info->tracing_multi.btf_obj_id = 
btf_obj_id(tr_link->link.prog->aux->attach_btf);
+       info->tracing_multi.tgt_progs = has_progs = !!tr_link->progs;
 
-       if (!uids && !ucookies && !uaddrs)
+       if (!uids && !ucookies && !uaddrs && !fids)
                return 0;
+       if (has_progs != !!fids)
+               return -EINVAL;
 
        if (ucount < tr_link->nodes_cnt)
                err = -ENOSPC;
@@ -3737,20 +3741,27 @@ static int bpf_tracing_multi_link_fill_link_info(const 
struct bpf_link *link,
 
        for (int i = 0; i < ucount; i++) {
                struct bpf_tracing_multi_node *mnode = &tr_link->nodes[i];
+               u32 prog_id, btf_id;
                u64 addr, cookie;
-               u32 id;
 
-               bpf_trampoline_unpack_key(mnode->trampoline->key, NULL, &id);
+               bpf_trampoline_unpack_key(mnode->trampoline->key, &prog_id, 
&btf_id);
 
-               addr = show_addrs ? mnode->trampoline->ip : 0;
+               if (!show_addrs)
+                       addr = 0;
+               else if (has_progs)
+                       addr = (u64) mnode->trampoline->func.addr;
+               else
+                       addr = mnode->trampoline->ip;
                cookie = has_cookies ? tr_link->cookies[i] : 0;
 
-               if (uids && put_user(id, uids + i))
+               if (uids && put_user(has_progs ? prog_id : btf_id, uids + i))
                        return -EFAULT;
                if (uaddrs && put_user(addr, uaddrs + i))
                        return -EFAULT;
                if (ucookies && put_user(cookie, ucookies + i))
                        return -EFAULT;
+               if (has_progs && put_user((u32) mnode->trampoline->key, fids + 
i))
+                       return -EFAULT;
 
                cond_resched();
        }
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 088d1d206065..d5c5ec433350 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -422,12 +422,30 @@ show_uprobe_multi_json(struct bpf_link_info *info, 
json_writer_t *wtr)
        jsonw_end_array(json_wtr);
 }
 
+#define BPF_PROG_PREFIX                "bpf_prog_"
+#define BPF_PROG_PREFIX_LEN    (sizeof(BPF_PROG_PREFIX) - 1)
+
+static const char *
+sym_name_trim_prefix(struct kernel_sym *sym, bool is_prog)
+{
+       int prefix_len;
+
+       if (!is_prog)
+               return sym->name;
+
+       /* Ref kernel/bpf/core.c::bpf_prog_ksym_set_name() */
+       prefix_len  = BPF_PROG_PREFIX_LEN;
+       prefix_len += BPF_TAG_SIZE * 2;
+       prefix_len += 1;                        /* skip the '_' */
+       return sym->name + prefix_len;
+}
+
 static void
 show_tracing_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
 {
-       bool is_ibt_enabled = is_x86_ibt_enabled(), show_symbol;
+       bool is_ibt_enabled = is_x86_ibt_enabled(), show_symbol, tgt_progs;
        __u64 *addrs, *cookies;
-       __u32 i, *ids;
+       __u32 i, *ids, *fids;
 
        if (!dd.sym_count)
                kernel_syms_load(&dd);
@@ -443,6 +461,8 @@ show_tracing_multi_json(struct bpf_link_info *info, 
json_writer_t *wtr)
        ids = u64_to_u32_arr(info->tracing_multi.ids);
        addrs = u64_to_arr(info->tracing_multi.addrs);
        cookies = u64_to_arr(info->tracing_multi.cookies);
+       fids = u64_to_u32_arr(info->tracing_multi.func_btf_ids);
+       tgt_progs = info->tracing_multi.tgt_progs;
 
        for (i = 0; i < info->tracing_multi.count; i++) {
                struct kernel_sym *sym;
@@ -451,10 +471,12 @@ show_tracing_multi_json(struct bpf_link_info *info, 
json_writer_t *wtr)
                sym = show_symbol ? find_kernel_sym_by_addr(addr, 
is_ibt_enabled) : NULL;
 
                jsonw_start_object(wtr);
-               jsonw_uint_field(wtr, "id", ids[i]);
+               jsonw_uint_field(wtr, tgt_progs ? "prog_id" : "id", ids[i]);
+               if (tgt_progs)
+                       jsonw_uint_field(wtr, "func_btf_id", fids[i]);
                jsonw_uint_field(wtr, "addr", addr);
                if (sym) {
-                       jsonw_string_field(wtr, "func", sym->name);
+                       jsonw_string_field(wtr, "func", 
sym_name_trim_prefix(sym, tgt_progs));
                        if (sym->module[0] == '\0') {
                                jsonw_name(wtr, "module");
                                jsonw_null(wtr);
@@ -903,9 +925,9 @@ static void show_uprobe_multi_plain(struct bpf_link_info 
*info)
 
 static void show_tracing_multi_plain(struct bpf_link_info *info)
 {
-       bool is_ibt_enabled = is_x86_ibt_enabled(), show_symbol;
+       bool is_ibt_enabled = is_x86_ibt_enabled(), show_symbol, tgt_progs;
        __u64 *addrs, *cookies;
-       __u32 i, *ids;
+       __u32 i, *ids, *fids;
 
        if (!info->tracing_multi.count)
                return;
@@ -919,12 +941,18 @@ static void show_tracing_multi_plain(struct bpf_link_info 
*info)
        printf("btf_obj_id %u  ", info->tracing_multi.btf_obj_id);
        printf("count %u  ", info->tracing_multi.count);
 
-       printf("\n\t%-16s %-16s %-16s %s",
-              "btf_id", "addr", "cookie", "func [module]");
+       tgt_progs = info->tracing_multi.tgt_progs;
+       if (tgt_progs)
+               printf("\n\t%-16s %-16s %-16s %-16s %s",
+                      "prog_id", "func_btf_id", "addr", "cookie", "func 
[module]");
+       else
+               printf("\n\t%-16s %-16s %-16s %s",
+                      "btf_id", "addr", "cookie", "func [module]");
 
        ids = u64_to_u32_arr(info->tracing_multi.ids);
        addrs = u64_to_arr(info->tracing_multi.addrs);
        cookies = u64_to_arr(info->tracing_multi.cookies);
+       fids = u64_to_u32_arr(info->tracing_multi.func_btf_ids);
 
        for (i = 0; i < info->tracing_multi.count; i++) {
                __u64 addr = addrs[i];
@@ -932,9 +960,12 @@ static void show_tracing_multi_plain(struct bpf_link_info 
*info)
 
                sym = show_symbol ? find_kernel_sym_by_addr(addr, 
is_ibt_enabled) : NULL;
 
-               printf("\n\t%-16u %016llx %-16llu", ids[i], addr, cookies[i]);
+               if (tgt_progs)
+                       printf("\n\t%-16u %-16u %016llx %-16llu", ids[i], 
fids[i], addr, cookies[i]);
+               else
+                       printf("\n\t%-16u %016llx %-16llu", ids[i], addr, 
cookies[i]);
                if (sym) {
-                       printf(" %s", sym->name);
+                       printf(" %s", sym_name_trim_prefix(sym, tgt_progs));
                        if (sym->module[0] != '\0')
                                printf(" [%s]", sym->module);
                }
@@ -1140,7 +1171,7 @@ static int show_link_close_plain(int fd, struct 
bpf_link_info *info)
 static int do_show_link(int fd)
 {
        __u64 *ref_ctr_offsets = NULL, *offsets = NULL, *cookies = NULL;
-       __u32 *ids = NULL;
+       __u32 *ids = NULL, *func_btf_ids = NULL;
        struct bpf_link_info info;
        __u32 len = sizeof(info);
        char path_buf[PATH_MAX];
@@ -1232,9 +1263,11 @@ static int do_show_link(int fd)
                        ids = calloc(count, sizeof(__u32));
                        addrs = calloc(count, sizeof(__u64));
                        cookies = calloc(count, sizeof(__u64));
-                       if (!ids || !addrs || !cookies) {
+                       func_btf_ids = info.tracing_multi.tgt_progs ? 
calloc(count, sizeof(__u32)) : NULL;
+                       if (!ids || !addrs || !cookies || 
(info.tracing_multi.tgt_progs && !func_btf_ids)) {
                                p_err("mem alloc failed");
                                close(fd);
+                               free(func_btf_ids);
                                free(cookies);
                                free(addrs);
                                free(ids);
@@ -1243,6 +1276,7 @@ static int do_show_link(int fd)
                        info.tracing_multi.ids = ptr_to_u64(ids);
                        info.tracing_multi.addrs = ptr_to_u64(addrs);
                        info.tracing_multi.cookies = ptr_to_u64(cookies);
+                       info.tracing_multi.func_btf_ids = 
ptr_to_u64(func_btf_ids);
                        goto again;
                }
        }
@@ -1282,6 +1316,7 @@ static int do_show_link(int fd)
                show_link_close_plain(fd, &info);
 
        free(ref_ctr_offsets);
+       free(func_btf_ids);
        free(cookies);
        free(offsets);
        free(addrs);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 6fa93a6ff54f..e0c8ea5ed2c8 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6890,10 +6890,12 @@ struct bpf_link_info {
                        __u32 attach_type;
                        __u32 count; /* in/out: tracing_multi target count */
                        __u32 btf_obj_id;
-                       __u32 :32;
+                       __u32 tgt_progs:1;
+                       __u32 :31;
                        __aligned_u64 ids;
                        __aligned_u64 addrs;
                        __aligned_u64 cookies;
+                       __aligned_u64 func_btf_ids;
                } tracing_multi;
                struct {
                        __u32 type; /* enum bpf_perf_event_type */
-- 
2.55.0


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