Commit 6b52ca44 authored by Michal Rostecki's avatar Michal Rostecki Committed by Daniel Borkmann
Browse files

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: default avatarMichal Rostecki <mrostecki@opensuse.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200226165941.6379-2-mrostecki@opensuse.org
parent 3494bec0

tools/bpf/bpftool/feature.c

+126 −93
Original line number Diff line number Diff line
@@ -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;

}

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