We need to let users check their wrong ELF section name
with proper ELF section names when failed to get a prog/attach type from it.
Because users can't realize libbpf guess prog/attach types from
given ELF section names.
For example, when a 'cgroup' section name of a BPF program is used,

Before:

    $ bpftool prog load bpf-prog.o /sys/fs/bpf/prog1
    Error: failed to guess program type based on ELF section name cgroup

After:

    libbpf: failed to guess program type based on ELF section name 'cgroup'
    libbpf: supported section(type) names are: socket kprobe/ kretprobe/ 
classifier action tracepoint/ raw_tracepoint/ xdp perf_event lwt_in lwt_out 
lwt_xmit lwt_seg6local cgroup_skb/ingress cgroup_skb/egress cgroup/skb 
cgroup/sock cgroup/post_bind4 cgroup/post_bind6 cgroup/dev sockops 
sk_skb/stream_parser sk_skb/stream_verdict sk_skb sk_msg lirc_mode2 
flow_dissector cgroup/bind4 cgroup/bind6 cgroup/connect4 cgroup/connect6 
cgroup/sendmsg4 cgroup/sendmsg6

In addtion, add pr_out printing without the "libbpf: " prefix.

Cc: Jakub Kicinski <jakub.kicin...@netronome.com>
Cc: Quentin Monnet <quentin.mon...@netronome.com>
Cc: Andrey Ignatov <r...@fb.com>
Signed-off-by: Taeung Song <treeze.tae...@gmail.com>
---
 tools/bpf/bpftool/prog.c                      | 10 ++----
 tools/lib/bpf/libbpf.c                        | 31 ++++++++++++++-----
 tools/lib/bpf/libbpf.h                        |  3 +-
 tools/lib/bpf/test_libbpf.cpp                 |  2 +-
 tools/perf/util/bpf-loader.c                  |  4 +--
 tools/testing/selftests/bpf/test_btf.c        |  2 +-
 .../testing/selftests/bpf/test_libbpf_open.c  |  4 +--
 tools/testing/selftests/bpf/test_progs.c      |  4 +--
 .../selftests/bpf/test_socket_cookie.c        |  4 +--
 9 files changed, 38 insertions(+), 26 deletions(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 2d1bb7d6ff51..0640e9bc0ada 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -930,10 +930,9 @@ static int load_with_options(int argc, char **argv, bool 
first_prog_only)
                        err = libbpf_prog_type_by_name(type, &attr.prog_type,
                                                       &expected_attach_type);
                        free(type);
-                       if (err < 0) {
-                               p_err("unknown program type '%s'", *argv);
+                       if (err < 0)
                                goto err_free_reuse_maps;
-                       }
+
                        NEXT_ARG();
                } else if (is_prefix(*argv, "map")) {
                        void *new_map_replace;
@@ -1028,11 +1027,8 @@ static int load_with_options(int argc, char **argv, bool 
first_prog_only)
 
                        err = libbpf_prog_type_by_name(sec_name, &prog_type,
                                                       &expected_attach_type);
-                       if (err < 0) {
-                               p_err("failed to guess program type based on 
section name %s\n",
-                                     sec_name);
+                       if (err < 0)
                                goto err_close_obj;
-                       }
                }
 
                bpf_program__set_ifindex(pos, ifindex);
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 169e347c76f6..55cb3f7cb3ee 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -68,24 +68,30 @@ static int __base_pr(const char *format, ...)
 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
+static __printf(1, 2) libbpf_print_fn_t __pr_out = __base_pr;
+
+#define pr_fmt(fmt) "libbpf: " fmt
 
 #define __pr(func, fmt, ...)   \
 do {                           \
        if ((func))             \
-               (func)("libbpf: " fmt, ##__VA_ARGS__); \
+               (func)(fmt, ##__VA_ARGS__); \
 } while (0)
 
-#define pr_warning(fmt, ...)   __pr(__pr_warning, fmt, ##__VA_ARGS__)
-#define pr_info(fmt, ...)      __pr(__pr_info, fmt, ##__VA_ARGS__)
-#define pr_debug(fmt, ...)     __pr(__pr_debug, fmt, ##__VA_ARGS__)
+#define pr_warning(fmt, ...)   __pr(__pr_warning, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_info(fmt, ...)      __pr(__pr_info, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_debug(fmt, ...)     __pr(__pr_debug, pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_out(fmt, ...)       __pr(__pr_out, fmt, ##__VA_ARGS__)
 
 void libbpf_set_print(libbpf_print_fn_t warn,
                      libbpf_print_fn_t info,
-                     libbpf_print_fn_t debug)
+                     libbpf_print_fn_t debug,
+                     libbpf_print_fn_t out)
 {
        __pr_warning = warn;
        __pr_info = info;
        __pr_debug = debug;
+       __pr_out = out;
 }
 
 #define STRERR_BUFSIZE  128
@@ -2682,6 +2688,12 @@ int libbpf_prog_type_by_name(const char *name, enum 
bpf_prog_type *prog_type,
                *expected_attach_type = section_names[i].expected_attach_type;
                return 0;
        }
+
+       pr_warning("failed to guess program type based on ELF section name 
'%s'\n", name);
+       pr_info("supported section(type) names are:");
+       for (i = 0; i < ARRAY_SIZE(section_names); i++)
+               pr_out(" %s", section_names[i].sec);
+       pr_out("\n");
        return -EINVAL;
 }
 
@@ -2701,6 +2713,13 @@ int libbpf_attach_type_by_name(const char *name,
                *attach_type = section_names[i].attach_type;
                return 0;
        }
+
+       pr_warning("failed to guess attach type based on ELF section name 
'%s'\n", name);
+       pr_info("attachable section(type) names are:");
+       for (i = 0; i < ARRAY_SIZE(section_names); i++)
+               if (section_names[i].is_attachable)
+                       pr_out(" %s", section_names[i].sec);
+       pr_out("\n");
        return -EINVAL;
 }
 
@@ -2907,8 +2926,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr 
*attr,
                        err = bpf_program__identify_section(prog, &prog_type,
                                                            
&expected_attach_type);
                        if (err < 0) {
-                               pr_warning("failed to guess program type based 
on section name %s\n",
-                                          prog->section_name);
                                bpf_object__close(obj);
                                return -EINVAL;
                        }
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5f68d7b75215..930c75012785 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -57,7 +57,8 @@ typedef int (*libbpf_print_fn_t)(const char *, ...)
 
 LIBBPF_API void libbpf_set_print(libbpf_print_fn_t warn,
                                 libbpf_print_fn_t info,
-                                libbpf_print_fn_t debug);
+                                libbpf_print_fn_t debug,
+                                libbpf_print_fn_t out);
 
 /* Hide internal to user */
 struct bpf_object;
diff --git a/tools/lib/bpf/test_libbpf.cpp b/tools/lib/bpf/test_libbpf.cpp
index abf3fc25c9fa..dcaf10c8b1a5 100644
--- a/tools/lib/bpf/test_libbpf.cpp
+++ b/tools/lib/bpf/test_libbpf.cpp
@@ -8,7 +8,7 @@
 int main(int argc, char *argv[])
 {
     /* libbpf.h */
-    libbpf_set_print(NULL, NULL, NULL);
+    libbpf_set_print(NULL, NULL, NULL, NULL);
 
     /* bpf.h */
     bpf_prog_get_fd_by_id(0);
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index f9ae1a993806..169dc8a7295e 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -61,7 +61,7 @@ bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, 
const char *name)
        if (!libbpf_initialized) {
                libbpf_set_print(libbpf_warning,
                                 libbpf_info,
-                                libbpf_debug);
+                                libbpf_debug, NULL);
                libbpf_initialized = true;
        }
 
@@ -81,7 +81,7 @@ struct bpf_object *bpf__prepare_load(const char *filename, 
bool source)
        if (!libbpf_initialized) {
                libbpf_set_print(libbpf_warning,
                                 libbpf_info,
-                                libbpf_debug);
+                                libbpf_debug, NULL);
                libbpf_initialized = true;
        }
 
diff --git a/tools/testing/selftests/bpf/test_btf.c 
b/tools/testing/selftests/bpf/test_btf.c
index 8bcd38010582..3b6b51fde1d1 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -5045,7 +5045,7 @@ int main(int argc, char **argv)
                return err;
 
        if (args.always_log)
-               libbpf_set_print(__base_pr, __base_pr, __base_pr);
+               libbpf_set_print(__base_pr, __base_pr, __base_pr, NULL);
 
        if (args.raw_test)
                err |= test_raw();
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c 
b/tools/testing/selftests/bpf/test_libbpf_open.c
index 8fcd1c076add..04bf536e5747 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -120,7 +120,7 @@ int main(int argc, char **argv)
        int longindex = 0;
        int opt;
 
-       libbpf_set_print(libbpf_warning, libbpf_info, NULL);
+       libbpf_set_print(libbpf_warning, libbpf_info, NULL, NULL);
 
        /* Parse commands line args */
        while ((opt = getopt_long(argc, argv, "hDq",
@@ -128,7 +128,7 @@ int main(int argc, char **argv)
                switch (opt) {
                case 'D':
                        libbpf_set_print(libbpf_warning, libbpf_info,
-                                        libbpf_debug);
+                                        libbpf_debug, NULL);
                        break;
                case 'q': /* Use in scripting mode */
                        verbose = 0;
diff --git a/tools/testing/selftests/bpf/test_progs.c 
b/tools/testing/selftests/bpf/test_progs.c
index 126fc624290d..969582c1f8c2 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -1776,9 +1776,9 @@ static void test_reference_tracking()
 
                /* Expect verifier failure if test name has 'fail' */
                if (strstr(title, "fail") != NULL) {
-                       libbpf_set_print(NULL, NULL, NULL);
+                       libbpf_set_print(NULL, NULL, NULL, NULL);
                        err = !bpf_program__load(prog, "GPL", 0);
-                       libbpf_set_print(printf, printf, NULL);
+                       libbpf_set_print(printf, printf, NULL, NULL);
                } else {
                        err = bpf_program__load(prog, "GPL", 0);
                }
diff --git a/tools/testing/selftests/bpf/test_socket_cookie.c 
b/tools/testing/selftests/bpf/test_socket_cookie.c
index b6c2c605d8c0..27c1576198d7 100644
--- a/tools/testing/selftests/bpf/test_socket_cookie.c
+++ b/tools/testing/selftests/bpf/test_socket_cookie.c
@@ -158,10 +158,8 @@ static int run_test(int cgfd)
        bpf_object__for_each_program(prog, pobj) {
                prog_name = bpf_program__title(prog, /*needs_copy*/ false);
 
-               if (libbpf_attach_type_by_name(prog_name, &attach_type)) {
-                       log_err("Unexpected prog: %s", prog_name);
+               if (libbpf_attach_type_by_name(prog_name, &attach_type))
                        goto err;
-               }
 
                err = bpf_prog_attach(bpf_program__fd(prog), cgfd, attach_type,
                                      BPF_F_ALLOW_OVERRIDE);
-- 
2.17.1

Reply via email to