[PATCH bpf-next v2 1/5] bpftool: Move out sections to separate functions

Michal Rostecki
2020-02-21T03:16:27Z

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>
---
tools/bpf/bpftool/feature.c | 219 +++++++++++++++++++++---------------
1 file changed, 126 insertions(+), 93 deletions(-)

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 941873d778d8..345e4a2b4f53 100644
--- 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;
}
--
2.25.0