diff --git a/tools/bpf/bpftool/Documentation/bpftool-feature.rst b/tools/bpf/bpftool/Documentation/bpftool-feature.rst index 255e3b3629a0..53092995f46b 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-feature.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-feature.rst @@ -19,15 +19,24 @@ SYNOPSIS MAP COMMANDS ============= -| **bpftool** **feature probe** [**kernel**] +| **bpftool** **feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]] | **bpftool** **feature help** DESCRIPTION =========== - **bpftool feature probe** [**kernel**] + **bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]] Probe the running kernel and dump a number of eBPF-related parameters, such as availability of the **bpf()** system call. + If the **macros** keyword (but not the **-j** option) is + passed, a subset of the output is dumped as a list of + **#define** macros that are ready to be included in a C + header file, for example. If, additionally, **prefix** is + used to define a *PREFIX*, the provided string will be used + as a prefix to the names of the macros: this can be used to + avoid conflicts on macro names when including the output of + this command as a header file. + Keyword **kernel** can be omitted. Note that when probed, some eBPF helpers (e.g. diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c index 55c8d215ca44..a62e637953b7 100644 --- a/tools/bpf/bpftool/feature.c +++ b/tools/bpf/bpftool/feature.c @@ -46,13 +46,25 @@ static bool check_procfs(void) return true; } +static void uppercase(char *str, size_t len) +{ + size_t i; + + for (i = 0; i < len && str[i] != '\0'; i++) + str[i] = toupper(str[i]); +} + /* Printing utility functions */ static void -print_bool_feature(const char *feat_name, const char *plain_name, bool res) +print_bool_feature(const char *feat_name, const char *plain_name, + const char *define_name, bool res, const char *define_prefix) { if (json_output) jsonw_bool_field(json_wtr, feat_name, res); + else if (define_prefix) + printf("#define %s%sHAVE_%s\n", define_prefix, + res ? "" : "NO_", define_name); else printf("%s is %savailable\n", plain_name, res ? "" : "NOT "); } @@ -62,6 +74,8 @@ static void print_kernel_option(const char *name, const char *value) char *endptr; int res; + /* No support for C-style ouptut */ + if (json_output) { if (!value) { jsonw_null_field(json_wtr, name); @@ -82,25 +96,31 @@ static void print_kernel_option(const char *name, const char *value) } static void -print_start_section(const char *json_title, const char *plain_title) +print_start_section(const char *json_title, const char *plain_title, + const char *define_comment, const char *define_prefix) { if (json_output) { jsonw_name(json_wtr, json_title); jsonw_start_object(json_wtr); + } else if (define_prefix) { + printf("%s\n", define_comment); } else { printf("%s\n", plain_title); } } static void -print_end_then_start_section(const char *json_title, const char *plain_title) +print_end_then_start_section(const char *json_title, const char *plain_title, + const char *define_comment, + const char *define_prefix) { if (json_output) jsonw_end_object(json_wtr); else printf("\n"); - print_start_section(json_title, plain_title); + print_start_section(json_title, plain_title, define_comment, + define_prefix); } /* Probing functions */ @@ -134,6 +154,8 @@ static void probe_unprivileged_disabled(void) { int res; + /* No support for C-style ouptut */ + res = read_procfs("/proc/sys/kernel/unprivileged_bpf_disabled"); if (json_output) { jsonw_int_field(json_wtr, "unprivileged_bpf_disabled", res); @@ -158,6 +180,8 @@ static void probe_jit_enable(void) { int res; + /* No support for C-style ouptut */ + res = read_procfs("/proc/sys/net/core/bpf_jit_enable"); if (json_output) { jsonw_int_field(json_wtr, "bpf_jit_enable", res); @@ -186,6 +210,8 @@ static void probe_jit_harden(void) { int res; + /* No support for C-style ouptut */ + res = read_procfs("/proc/sys/net/core/bpf_jit_harden"); if (json_output) { jsonw_int_field(json_wtr, "bpf_jit_harden", res); @@ -214,6 +240,8 @@ static void probe_jit_kallsyms(void) { int res; + /* No support for C-style ouptut */ + res = read_procfs("/proc/sys/net/core/bpf_jit_kallsyms"); if (json_output) { jsonw_int_field(json_wtr, "bpf_jit_kallsyms", res); @@ -238,6 +266,8 @@ static void probe_jit_limit(void) { int res; + /* No support for C-style ouptut */ + res = read_procfs("/proc/sys/net/core/bpf_jit_limit"); if (json_output) { jsonw_int_field(json_wtr, "bpf_jit_limit", res); @@ -409,7 +439,7 @@ no_config: print_kernel_option(options[i], NULL); } -static bool probe_bpf_syscall(void) +static bool probe_bpf_syscall(const char *define_prefix) { bool res; @@ -418,15 +448,18 @@ static bool probe_bpf_syscall(void) print_bool_feature("have_bpf_syscall", "bpf() syscall", - res); + "BPF_SYSCALL", + res, define_prefix); return res; } -static void probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types) +static void +probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types, + const char *define_prefix) { + char feat_name[128], plain_desc[128], define_name[128]; const char *plain_comment = "eBPF program_type "; - char feat_name[128], plain_desc[128]; size_t maxlen; bool res; @@ -441,14 +474,18 @@ static void probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types) } sprintf(feat_name, "have_%s_prog_type", prog_type_name[prog_type]); + sprintf(define_name, "%s_prog_type", prog_type_name[prog_type]); + uppercase(define_name, sizeof(define_name)); sprintf(plain_desc, "%s%s", plain_comment, prog_type_name[prog_type]); - print_bool_feature(feat_name, plain_desc, res); + print_bool_feature(feat_name, plain_desc, define_name, res, + define_prefix); } -static void probe_map_type(enum bpf_map_type map_type) +static void +probe_map_type(enum bpf_map_type map_type, const char *define_prefix) { + char feat_name[128], plain_desc[128], define_name[128]; const char *plain_comment = "eBPF map_type "; - char feat_name[128], plain_desc[128]; size_t maxlen; bool res; @@ -461,12 +498,16 @@ static void probe_map_type(enum bpf_map_type map_type) } sprintf(feat_name, "have_%s_map_type", map_type_name[map_type]); + sprintf(define_name, "%s_map_type", map_type_name[map_type]); + uppercase(define_name, sizeof(define_name)); sprintf(plain_desc, "%s%s", plain_comment, map_type_name[map_type]); - print_bool_feature(feat_name, plain_desc, res); + print_bool_feature(feat_name, plain_desc, define_name, res, + define_prefix); } static void -probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type) +probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type, + const char *define_prefix) { const char *ptype_name = prog_type_name[prog_type]; char feat_name[128]; @@ -477,7 +518,7 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type) sprintf(feat_name, "%s_available_helpers", ptype_name); jsonw_name(json_wtr, feat_name); jsonw_start_array(json_wtr); - } else { + } else if (!define_prefix) { printf("eBPF helpers supported for program type %s:", ptype_name); } @@ -491,6 +532,10 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type) if (json_output) { if (res) jsonw_string(json_wtr, helper_name[id]); + } else if (define_prefix) { + printf("#define %sBPF__PROG_TYPE_%s__HELPER_%s %s\n", + define_prefix, ptype_name, helper_name[id], + res ? "1" : "0"); } else { if (res) printf("\n\t- %s", helper_name[id]); @@ -499,13 +544,14 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type) if (json_output) jsonw_end_array(json_wtr); - else + else if (!define_prefix) printf("\n"); } static int do_probe(int argc, char **argv) { enum probe_component target = COMPONENT_UNSPEC; + const char *define_prefix = NULL; bool supported_types[128] = {}; unsigned int i; @@ -527,21 +573,45 @@ static int do_probe(int argc, char **argv) } target = COMPONENT_KERNEL; NEXT_ARG(); + } else if (is_prefix(*argv, "macros") && !define_prefix) { + define_prefix = ""; + NEXT_ARG(); + } else if (is_prefix(*argv, "prefix")) { + if (!define_prefix) { + p_err("'prefix' argument can only be use after 'macros'"); + return -1; + } + if (strcmp(define_prefix, "")) { + p_err("'prefix' already defined"); + return -1; + } + NEXT_ARG(); + + if (!REQ_ARGS(1)) + return -1; + define_prefix = GET_ARG(); } else { - p_err("expected no more arguments, 'kernel', got: '%s'?", + p_err("expected no more arguments, 'kernel', 'macros' or 'prefix', got: '%s'?", *argv); return -1; } } - if (json_output) + if (json_output) { + define_prefix = NULL; 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..."); + "Scanning system configuration...", + NULL, /* define_comment never used here */ + NULL); /* define_prefix always NULL here */ if (check_procfs()) { probe_unprivileged_disabled(); probe_jit_enable(); @@ -560,29 +630,53 @@ static int do_probe(int argc, char **argv) } print_start_section("syscall_config", - "Scanning system call availability..."); + "Scanning system call availability...", + "/*** System call availability ***/", + define_prefix); - if (!probe_bpf_syscall()) + if (!probe_bpf_syscall(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..."); + "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); + probe_prog_type(i, supported_types, define_prefix); print_end_then_start_section("map_types", - "Scanning eBPF 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); + probe_map_type(i, define_prefix); print_end_then_start_section("helpers", - "Scanning eBPF helper functions..."); + "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 is available for ,\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]); + probe_helpers_for_progtype(i, supported_types[i], + define_prefix); exit_close_json: if (json_output) { @@ -603,7 +697,7 @@ static int do_help(int argc, char **argv) } fprintf(stderr, - "Usage: %s %s probe [kernel]\n" + "Usage: %s %s probe [kernel] [macros [prefix PREFIX]]\n" " %s %s help\n" "", bin_name, argv[-2], bin_name, argv[-2]);