bpftool: Move out sections to separate functions

Remove all calls of print_end_then_start_section function and for loops
out from the do_probe function. Instead, provide separate functions for
each section (like i.e. section_helpers) which are called in do_probe.
This change is motivated by better readability.

Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200226165941.6379-2-mrostecki@opensuse.org

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 941873d..345e4a2 100644 (file)
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -112,18 +112,12 @@ print_start_section(const char *json_title, const char *plain_title,
        }
 }
 
-static void
-print_end_then_start_section(const char *json_title, const char *plain_title,
-                            const char *define_comment,
-                            const char *define_prefix)
+static void print_end_section(void)
 {
        if (json_output)
                jsonw_end_object(json_wtr);
        else
                printf("\n");
-
-       print_start_section(json_title, plain_title, define_comment,
-                           define_prefix);
 }
 
 /* Probing functions */
@@ -584,13 +578,130 @@ probe_large_insn_limit(const char *define_prefix, __u32 ifindex)
                           res, define_prefix);
 }
 
+static void
+section_system_config(enum probe_component target, const char *define_prefix)
+{
+       switch (target) {
+       case COMPONENT_KERNEL:
+       case COMPONENT_UNSPEC:
+               if (define_prefix)
+                       break;
+
+               print_start_section("system_config",
+                                   "Scanning system configuration...",
+                                   NULL, /* define_comment never used here */
+                                   NULL); /* define_prefix always NULL here */
+               if (check_procfs()) {
+                       probe_unprivileged_disabled();
+                       probe_jit_enable();
+                       probe_jit_harden();
+                       probe_jit_kallsyms();
+                       probe_jit_limit();
+               } else {
+                       p_info("/* procfs not mounted, skipping related probes */");
+               }
+               probe_kernel_image_config();
+               print_end_section();
+               break;
+       default:
+               break;
+       }
+}
+
+static bool section_syscall_config(const char *define_prefix)
+{
+       bool res;
+
+       print_start_section("syscall_config",
+                           "Scanning system call availability...",
+                           "/*** System call availability ***/",
+                           define_prefix);
+       res = probe_bpf_syscall(define_prefix);
+       print_end_section();
+
+       return res;
+}
+
+static void
+section_program_types(bool *supported_types, const char *define_prefix,
+                     __u32 ifindex)
+{
+       unsigned int i;
+
+       print_start_section("program_types",
+                           "Scanning eBPF program types...",
+                           "/*** eBPF program types ***/",
+                           define_prefix);
+
+       for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
+               probe_prog_type(i, supported_types, define_prefix, ifindex);
+
+       print_end_section();
+}
+
+static void section_map_types(const char *define_prefix, __u32 ifindex)
+{
+       unsigned int i;
+
+       print_start_section("map_types",
+                           "Scanning eBPF map types...",
+                           "/*** eBPF map types ***/",
+                           define_prefix);
+
+       for (i = BPF_MAP_TYPE_UNSPEC + 1; i < map_type_name_size; i++)
+               probe_map_type(i, define_prefix, ifindex);
+
+       print_end_section();
+}
+
+static void
+section_helpers(bool *supported_types, const char *define_prefix, __u32 ifindex)
+{
+       unsigned int i;
+
+       print_start_section("helpers",
+                           "Scanning eBPF helper functions...",
+                           "/*** eBPF helper functions ***/",
+                           define_prefix);
+
+       if (define_prefix)
+               printf("/*\n"
+                      " * Use %sHAVE_PROG_TYPE_HELPER(prog_type_name, helper_name)\n"
+                      " * to determine if <helper_name> is available for <prog_type_name>,\n"
+                      " * e.g.\n"
+                      " *      #if %sHAVE_PROG_TYPE_HELPER(xdp, bpf_redirect)\n"
+                      " *              // do stuff with this helper\n"
+                      " *      #elif\n"
+                      " *              // use a workaround\n"
+                      " *      #endif\n"
+                      " */\n"
+                      "#define %sHAVE_PROG_TYPE_HELPER(prog_type, helper)      \\\n"
+                      "        %sBPF__PROG_TYPE_ ## prog_type ## __HELPER_ ## helper\n",
+                      define_prefix, define_prefix, define_prefix,
+                      define_prefix);
+       for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
+               probe_helpers_for_progtype(i, supported_types[i],
+                                          define_prefix, ifindex);
+
+       print_end_section();
+}
+
+static void section_misc(const char *define_prefix, __u32 ifindex)
+{
+       print_start_section("misc",
+                           "Scanning miscellaneous eBPF features...",
+                           "/*** eBPF misc features ***/",
+                           define_prefix);
+       probe_large_insn_limit(define_prefix, ifindex);
+       print_end_section();
+}
+
 static int do_probe(int argc, char **argv)
 {
        enum probe_component target = COMPONENT_UNSPEC;
        const char *define_prefix = NULL;
        bool supported_types[128] = {};
        __u32 ifindex = 0;
-       unsigned int i;
        char *ifname;
 
        /* Detection assumes user has sufficient privileges (CAP_SYS_ADMIN).
@@ -658,97 +769,19 @@ static int do_probe(int argc, char **argv)
                jsonw_start_object(json_wtr);
        }
 
-       switch (target) {
-       case COMPONENT_KERNEL:
-       case COMPONENT_UNSPEC:
-               if (define_prefix)
-                       break;
-
-               print_start_section("system_config",
-                                   "Scanning system configuration...",
-                                   NULL, /* define_comment never used here */
-                                   NULL); /* define_prefix always NULL here */
-               if (check_procfs()) {
-                       probe_unprivileged_disabled();
-                       probe_jit_enable();
-                       probe_jit_harden();
-                       probe_jit_kallsyms();
-                       probe_jit_limit();
-               } else {
-                       p_info("/* procfs not mounted, skipping related probes */");
-               }
-               probe_kernel_image_config();
-               if (json_output)
-                       jsonw_end_object(json_wtr);
-               else
-                       printf("\n");
-               break;
-       default:
-               break;
-       }
-
-       print_start_section("syscall_config",
-                           "Scanning system call availability...",
-                           "/*** System call availability ***/",
-                           define_prefix);
-
-       if (!probe_bpf_syscall(define_prefix))
+       section_system_config(target, define_prefix);
+       if (!section_syscall_config(define_prefix))
                /* bpf() syscall unavailable, don't probe other BPF features */
                goto exit_close_json;
-
-       print_end_then_start_section("program_types",
-                                    "Scanning eBPF program types...",
-                                    "/*** eBPF program types ***/",
-                                    define_prefix);
-
-       for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
-               probe_prog_type(i, supported_types, define_prefix, ifindex);
-
-       print_end_then_start_section("map_types",
-                                    "Scanning eBPF map types...",
-                                    "/*** eBPF map types ***/",
-                                    define_prefix);
-
-       for (i = BPF_MAP_TYPE_UNSPEC + 1; i < map_type_name_size; i++)
-               probe_map_type(i, define_prefix, ifindex);
-
-       print_end_then_start_section("helpers",
-                                    "Scanning eBPF helper functions...",
-                                    "/*** eBPF helper functions ***/",
-                                    define_prefix);
-
-       if (define_prefix)
-               printf("/*\n"
-                      " * Use %sHAVE_PROG_TYPE_HELPER(prog_type_name, helper_name)\n"
-                      " * to determine if <helper_name> is available for <prog_type_name>,\n"
-                      " * e.g.\n"
-                      " *      #if %sHAVE_PROG_TYPE_HELPER(xdp, bpf_redirect)\n"
-                      " *              // do stuff with this helper\n"
-                      " *      #elif\n"
-                      " *              // use a workaround\n"
-                      " *      #endif\n"
-                      " */\n"
-                      "#define %sHAVE_PROG_TYPE_HELPER(prog_type, helper)      \\\n"
-                      "        %sBPF__PROG_TYPE_ ## prog_type ## __HELPER_ ## helper\n",
-                      define_prefix, define_prefix, define_prefix,
-                      define_prefix);
-       for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
-               probe_helpers_for_progtype(i, supported_types[i],
-                                          define_prefix, ifindex);
-
-       print_end_then_start_section("misc",
-                                    "Scanning miscellaneous eBPF features...",
-                                    "/*** eBPF misc features ***/",
-                                    define_prefix);
-       probe_large_insn_limit(define_prefix, ifindex);
+       section_program_types(supported_types, define_prefix, ifindex);
+       section_map_types(define_prefix, ifindex);
+       section_helpers(supported_types, define_prefix, ifindex);
+       section_misc(define_prefix, ifindex);
 
 exit_close_json:
-       if (json_output) {
-               /* End current "section" of probes */
-               jsonw_end_object(json_wtr);
+       if (json_output)
                /* End root object */
                jsonw_end_object(json_wtr);
-       }
 
        return 0;
 }