From c5481f9a954f27b8730c1dfeebbc9b3b5b2b2481 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 28 Apr 2020 17:16:12 -0700 Subject: [PATCH] bpftool: Add bpf_link show and pin support Add `bpftool link show` and `bpftool link pin` commands. Example plain output for `link show` (with showing pinned paths): [vmuser@archvm bpf]$ sudo ~/local/linux/tools/bpf/bpftool/bpftool -f link 1: tracing prog 12 prog_type tracing attach_type fentry pinned /sys/fs/bpf/my_test_link pinned /sys/fs/bpf/my_test_link2 2: tracing prog 13 prog_type tracing attach_type fentry 3: tracing prog 14 prog_type tracing attach_type fentry 4: tracing prog 15 prog_type tracing attach_type fentry 5: tracing prog 16 prog_type tracing attach_type fentry 6: tracing prog 17 prog_type tracing attach_type fentry 7: raw_tracepoint prog 21 tp 'sys_enter' 8: cgroup prog 25 cgroup_id 584 attach_type egress 9: cgroup prog 25 cgroup_id 599 attach_type egress 10: cgroup prog 25 cgroup_id 614 attach_type egress 11: cgroup prog 25 cgroup_id 629 attach_type egress Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200429001614.1544-9-andriin@fb.com --- tools/bpf/bpftool/common.c | 2 + tools/bpf/bpftool/link.c | 333 +++++++++++++++++++++++++++++++++++++ tools/bpf/bpftool/main.c | 6 +- tools/bpf/bpftool/main.h | 5 + 4 files changed, 345 insertions(+), 1 deletion(-) create mode 100644 tools/bpf/bpftool/link.c diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index f2223dbdfb0a..c47bdc65de8e 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -262,6 +262,8 @@ int get_fd_type(int fd) return BPF_OBJ_MAP; else if (strstr(buf, "bpf-prog")) return BPF_OBJ_PROG; + else if (strstr(buf, "bpf-link")) + return BPF_OBJ_LINK; return BPF_OBJ_UNKNOWN; } diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c new file mode 100644 index 000000000000..adc7dc431ed8 --- /dev/null +++ b/tools/bpf/bpftool/link.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (C) 2020 Facebook */ + +#include +#include +#include +#include + +#include + +#include "json_writer.h" +#include "main.h" + +static const char * const link_type_name[] = { + [BPF_LINK_TYPE_UNSPEC] = "unspec", + [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_LINK_TYPE_TRACING] = "tracing", + [BPF_LINK_TYPE_CGROUP] = "cgroup", +}; + +static int link_parse_fd(int *argc, char ***argv) +{ + if (is_prefix(**argv, "id")) { + unsigned int id; + char *endptr; + + NEXT_ARGP(); + + id = strtoul(**argv, &endptr, 0); + if (*endptr) { + p_err("can't parse %s as ID", **argv); + return -1; + } + NEXT_ARGP(); + + return bpf_link_get_fd_by_id(id); + } else if (is_prefix(**argv, "pinned")) { + char *path; + + NEXT_ARGP(); + + path = **argv; + NEXT_ARGP(); + + return open_obj_pinned_any(path, BPF_OBJ_LINK); + } + + p_err("expected 'id' or 'pinned', got: '%s'?", **argv); + return -1; +} + +static void +show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_uint_field(wtr, "id", info->id); + if (info->type < ARRAY_SIZE(link_type_name)) + jsonw_string_field(wtr, "type", link_type_name[info->type]); + else + jsonw_uint_field(wtr, "type", info->type); + + jsonw_uint_field(json_wtr, "prog_id", info->prog_id); +} + +static int get_prog_info(int prog_id, struct bpf_prog_info *info) +{ + __u32 len = sizeof(*info); + int err, prog_fd; + + prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (prog_fd < 0) + return prog_fd; + + memset(info, 0, sizeof(*info)); + err = bpf_obj_get_info_by_fd(prog_fd, info, &len); + if (err) + p_err("can't get prog info: %s", strerror(errno)); + close(prog_fd); + return err; +} + +static int show_link_close_json(int fd, struct bpf_link_info *info) +{ + struct bpf_prog_info prog_info; + int err; + + jsonw_start_object(json_wtr); + + show_link_header_json(info, json_wtr); + + switch (info->type) { + case BPF_LINK_TYPE_RAW_TRACEPOINT: + jsonw_string_field(json_wtr, "tp_name", + (const char *)info->raw_tracepoint.tp_name); + break; + case BPF_LINK_TYPE_TRACING: + err = get_prog_info(info->prog_id, &prog_info); + if (err) + return err; + + if (prog_info.type < ARRAY_SIZE(prog_type_name)) + jsonw_string_field(json_wtr, "prog_type", + prog_type_name[prog_info.type]); + else + jsonw_uint_field(json_wtr, "prog_type", + prog_info.type); + + if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name)) + jsonw_string_field(json_wtr, "attach_type", + attach_type_name[info->tracing.attach_type]); + else + jsonw_uint_field(json_wtr, "attach_type", + info->tracing.attach_type); + break; + case BPF_LINK_TYPE_CGROUP: + jsonw_lluint_field(json_wtr, "cgroup_id", + info->cgroup.cgroup_id); + if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name)) + jsonw_string_field(json_wtr, "attach_type", + attach_type_name[info->cgroup.attach_type]); + else + jsonw_uint_field(json_wtr, "attach_type", + info->cgroup.attach_type); + break; + default: + break; + } + + if (!hash_empty(link_table.table)) { + struct pinned_obj *obj; + + jsonw_name(json_wtr, "pinned"); + jsonw_start_array(json_wtr); + hash_for_each_possible(link_table.table, obj, hash, info->id) { + if (obj->id == info->id) + jsonw_string(json_wtr, obj->path); + } + jsonw_end_array(json_wtr); + } + jsonw_end_object(json_wtr); + + return 0; +} + +static void show_link_header_plain(struct bpf_link_info *info) +{ + printf("%u: ", info->id); + if (info->type < ARRAY_SIZE(link_type_name)) + printf("%s ", link_type_name[info->type]); + else + printf("type %u ", info->type); + + printf("prog %u ", info->prog_id); +} + +static int show_link_close_plain(int fd, struct bpf_link_info *info) +{ + struct bpf_prog_info prog_info; + int err; + + show_link_header_plain(info); + + switch (info->type) { + case BPF_LINK_TYPE_RAW_TRACEPOINT: + printf("\n\ttp '%s' ", + (const char *)info->raw_tracepoint.tp_name); + break; + case BPF_LINK_TYPE_TRACING: + err = get_prog_info(info->prog_id, &prog_info); + if (err) + return err; + + if (prog_info.type < ARRAY_SIZE(prog_type_name)) + printf("\n\tprog_type %s ", + prog_type_name[prog_info.type]); + else + printf("\n\tprog_type %u ", prog_info.type); + + if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name)) + printf("attach_type %s ", + attach_type_name[info->tracing.attach_type]); + else + printf("attach_type %u ", info->tracing.attach_type); + break; + case BPF_LINK_TYPE_CGROUP: + printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id); + if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name)) + printf("attach_type %s ", + attach_type_name[info->cgroup.attach_type]); + else + printf("attach_type %u ", info->cgroup.attach_type); + break; + default: + break; + } + + if (!hash_empty(link_table.table)) { + struct pinned_obj *obj; + + hash_for_each_possible(link_table.table, obj, hash, info->id) { + if (obj->id == info->id) + printf("\n\tpinned %s", obj->path); + } + } + + printf("\n"); + + return 0; +} + +static int do_show_link(int fd) +{ + struct bpf_link_info info; + __u32 len = sizeof(info); + char raw_tp_name[256]; + int err; + + memset(&info, 0, sizeof(info)); +again: + err = bpf_obj_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get link info: %s", + strerror(errno)); + close(fd); + return err; + } + if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT && + !info.raw_tracepoint.tp_name) { + info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name; + info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name); + goto again; + } + + if (json_output) + show_link_close_json(fd, &info); + else + show_link_close_plain(fd, &info); + + close(fd); + return 0; +} + +static int do_show(int argc, char **argv) +{ + __u32 id = 0; + int err, fd; + + if (show_pinned) + build_pinned_obj_table(&link_table, BPF_OBJ_LINK); + + if (argc == 2) { + fd = link_parse_fd(&argc, &argv); + if (fd < 0) + return fd; + return do_show_link(fd); + } + + if (argc) + return BAD_ARG(); + + if (json_output) + jsonw_start_array(json_wtr); + while (true) { + err = bpf_link_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) + break; + p_err("can't get next link: %s%s", strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + break; + } + + fd = bpf_link_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get link by id (%u): %s", + id, strerror(errno)); + break; + } + + err = do_show_link(fd); + if (err) + break; + } + if (json_output) + jsonw_end_array(json_wtr); + + return errno == ENOENT ? 0 : -1; +} + +static int do_pin(int argc, char **argv) +{ + int err; + + err = do_pin_any(argc, argv, link_parse_fd); + if (!err && json_output) + jsonw_null(json_wtr); + return err; +} + +static int do_help(int argc, char **argv) +{ + if (json_output) { + jsonw_null(json_wtr); + return 0; + } + + fprintf(stderr, + "Usage: %1$s %2$s { show | list } [LINK]\n" + " %1$s %2$s pin LINK FILE\n" + " %1$s %2$s help\n" + "\n" + " " HELP_SPEC_LINK "\n" + " " HELP_SPEC_PROGRAM "\n" + " " HELP_SPEC_OPTIONS "\n" + "", + bin_name, argv[-2]); + + return 0; +} + +static const struct cmd cmds[] = { + { "show", do_show }, + { "list", do_show }, + { "help", do_help }, + { "pin", do_pin }, + { 0 } +}; + +int do_link(int argc, char **argv) +{ + return cmd_select(cmds, argc, argv, do_help); +} diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 466c269eabdd..1413a154806e 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -30,6 +30,7 @@ bool verifier_logs; bool relaxed_maps; struct pinned_obj_table prog_table; struct pinned_obj_table map_table; +struct pinned_obj_table link_table; static void __noreturn clean_and_exit(int i) { @@ -58,7 +59,7 @@ static int do_help(int argc, char **argv) " %s batch file FILE\n" " %s version\n" "\n" - " OBJECT := { prog | map | cgroup | perf | net | feature | btf | gen | struct_ops }\n" + " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops }\n" " " HELP_SPEC_OPTIONS "\n" "", bin_name, bin_name, bin_name); @@ -215,6 +216,7 @@ static const struct cmd cmds[] = { { "batch", do_batch }, { "prog", do_prog }, { "map", do_map }, + { "link", do_link }, { "cgroup", do_cgroup }, { "perf", do_perf }, { "net", do_net }, @@ -364,6 +366,7 @@ int main(int argc, char **argv) hash_init(prog_table.table); hash_init(map_table.table); + hash_init(link_table.table); opterr = 0; while ((opt = getopt_long(argc, argv, "Vhpjfmnd", @@ -422,6 +425,7 @@ int main(int argc, char **argv) if (show_pinned) { delete_pinned_obj_table(&prog_table); delete_pinned_obj_table(&map_table); + delete_pinned_obj_table(&link_table); } return ret; diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 99d84bd1d5b2..9b1fb81a8331 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -50,6 +50,8 @@ "\t {-m|--mapcompat} | {-n|--nomount} }" #define HELP_SPEC_MAP \ "MAP := { id MAP_ID | pinned FILE | name MAP_NAME }" +#define HELP_SPEC_LINK \ + "LINK := { id LINK_ID | pinned FILE }" static const char * const prog_type_name[] = { [BPF_PROG_TYPE_UNSPEC] = "unspec", @@ -122,6 +124,7 @@ enum bpf_obj_type { BPF_OBJ_UNKNOWN, BPF_OBJ_PROG, BPF_OBJ_MAP, + BPF_OBJ_LINK, }; extern const char *bin_name; @@ -134,6 +137,7 @@ extern bool verifier_logs; extern bool relaxed_maps; extern struct pinned_obj_table prog_table; extern struct pinned_obj_table map_table; +extern struct pinned_obj_table link_table; void __printf(1, 2) p_err(const char *fmt, ...); void __printf(1, 2) p_info(const char *fmt, ...); @@ -185,6 +189,7 @@ int do_pin_fd(int fd, const char *name); int do_prog(int argc, char **arg); int do_map(int argc, char **arg); +int do_link(int argc, char **arg); int do_event_pipe(int argc, char **argv); int do_cgroup(int argc, char **arg); int do_perf(int argc, char **arg);