From 8f184732b60b74a8f8ba0d9a5c248bf611b1ebba Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Sat, 23 Oct 2021 21:51:52 +0100 Subject: [PATCH] bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects In order to show pinned paths for BPF programs, maps, or links when listing them with the "-f" option, bpftool creates hash maps to store all relevant paths under the bpffs. So far, it would rely on the kernel implementation (from tools/include/linux/hashtable.h). We can make bpftool rely on libbpf's implementation instead. The motivation is to make bpftool less dependent of kernel headers, to ease the path to a potential out-of-tree mirror, like libbpf has. This commit is the first step of the conversion: the hash maps for pinned paths for programs, maps, and links are converted to libbpf's hashmap.{c,h}. Other hash maps used for the PIDs of process holding references to BPF objects are left unchanged for now. On the build side, this requires adding a dependency to a second header internal to libbpf, and making it a dependency for the bootstrap bpftool version as well. The rest of the changes are a rather straightforward conversion. Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211023205154.6710-4-quentin@isovalent.com --- tools/bpf/bpftool/Makefile | 8 ++++---- tools/bpf/bpftool/common.c | 50 +++++++++++++++++++++++++++------------------- tools/bpf/bpftool/link.c | 36 ++++++++++++++++++--------------- tools/bpf/bpftool/main.h | 29 ++++++++++++++++----------- tools/bpf/bpftool/map.c | 36 ++++++++++++++++++--------------- tools/bpf/bpftool/prog.c | 36 ++++++++++++++++++--------------- 6 files changed, 111 insertions(+), 84 deletions(-) diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 939b0fc..c0c30e5 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -31,9 +31,9 @@ LIBBPF = $(LIBBPF_OUTPUT)libbpf.a LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/ LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a -# We need to copy nlattr.h which is not otherwise exported by libbpf, but still -# required by bpftool. -LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,nlattr.h) +# We need to copy hashmap.h and nlattr.h which is not otherwise exported by +# libbpf, but still required by bpftool. +LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h) ifeq ($(BPFTOOL_VERSION),) BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion) @@ -209,7 +209,7 @@ $(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP) $(OUTPUT)bpftool: $(OBJS) $(LIBBPF) $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS) -$(BOOTSTRAP_OUTPUT)%.o: %.c | $(BOOTSTRAP_OUTPUT) +$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT) $(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $< $(OUTPUT)%.o: %.c diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index d42d930..511eccd 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -22,6 +22,7 @@ #include #include +#include #include /* libbpf_num_possible_cpus */ #include "main.h" @@ -393,7 +394,7 @@ void print_hex_data_json(uint8_t *data, size_t len) } /* extra params for nftw cb */ -static struct pinned_obj_table *build_fn_table; +static struct hashmap *build_fn_table; static enum bpf_obj_type build_fn_type; static int do_build_table_cb(const char *fpath, const struct stat *sb, @@ -401,9 +402,9 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb, { struct bpf_prog_info pinned_info; __u32 len = sizeof(pinned_info); - struct pinned_obj *obj_node; enum bpf_obj_type objtype; int fd, err = 0; + char *path; if (typeflag != FTW_F) goto out_ret; @@ -420,28 +421,26 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb, if (bpf_obj_get_info_by_fd(fd, &pinned_info, &len)) goto out_close; - obj_node = calloc(1, sizeof(*obj_node)); - if (!obj_node) { + path = strdup(fpath); + if (!path) { err = -1; goto out_close; } - obj_node->id = pinned_info.id; - obj_node->path = strdup(fpath); - if (!obj_node->path) { - err = -1; - free(obj_node); + err = hashmap__append(build_fn_table, u32_as_hash_field(pinned_info.id), path); + if (err) { + p_err("failed to append entry to hashmap for ID %u, path '%s': %s", + pinned_info.id, path, strerror(errno)); goto out_close; } - hash_add(build_fn_table->table, &obj_node->hash, obj_node->id); out_close: close(fd); out_ret: return err; } -int build_pinned_obj_table(struct pinned_obj_table *tab, +int build_pinned_obj_table(struct hashmap *tab, enum bpf_obj_type type) { struct mntent *mntent = NULL; @@ -470,17 +469,18 @@ int build_pinned_obj_table(struct pinned_obj_table *tab, return err; } -void delete_pinned_obj_table(struct pinned_obj_table *tab) +void delete_pinned_obj_table(struct hashmap *map) { - struct pinned_obj *obj; - struct hlist_node *tmp; - unsigned int bkt; + struct hashmap_entry *entry; + size_t bkt; - hash_for_each_safe(tab->table, bkt, tmp, obj, hash) { - hash_del(&obj->hash); - free(obj->path); - free(obj); - } + if (!map) + return; + + hashmap__for_each_entry(map, entry, bkt) + free(entry->value); + + hashmap__free(map); } unsigned int get_page_size(void) @@ -962,3 +962,13 @@ int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len) return fd; } + +size_t hash_fn_for_key_as_id(const void *key, void *ctx) +{ + return (size_t)key; +} + +bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx) +{ + return k1 == k2; +} diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index a5effb1..404cc54 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -7,6 +7,7 @@ #include #include +#include #include "json_writer.h" #include "main.h" @@ -20,7 +21,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_NETNS] = "netns", }; -static struct pinned_obj_table link_table; +static struct hashmap *link_table; static int link_parse_fd(int *argc, char ***argv) { @@ -158,15 +159,14 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) break; } - if (!hash_empty(link_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(link_table)) { + struct hashmap_entry *entry; 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); - } + hashmap__for_each_key_entry(link_table, entry, + u32_as_hash_field(info->id)) + jsonw_string(json_wtr, entry->value); jsonw_end_array(json_wtr); } @@ -246,13 +246,12 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info) break; } - if (!hash_empty(link_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(link_table)) { + struct hashmap_entry *entry; - hash_for_each_possible(link_table.table, obj, hash, info->id) { - if (obj->id == info->id) - printf("\n\tpinned %s", obj->path); - } + hashmap__for_each_key_entry(link_table, entry, + u32_as_hash_field(info->id)) + printf("\n\tpinned %s", (char *)entry->value); } emit_obj_refs_plain(&refs_table, info->id, "\n\tpids "); @@ -305,8 +304,13 @@ static int do_show(int argc, char **argv) int err, fd; if (show_pinned) { - hash_init(link_table.table); - build_pinned_obj_table(&link_table, BPF_OBJ_LINK); + link_table = hashmap__new(hash_fn_for_key_as_id, + equal_fn_for_key_as_id, NULL); + if (!link_table) { + p_err("failed to create hashmap for pinned paths"); + return -1; + } + build_pinned_obj_table(link_table, BPF_OBJ_LINK); } build_obj_refs_table(&refs_table, BPF_OBJ_LINK); @@ -351,7 +355,7 @@ static int do_show(int argc, char **argv) delete_obj_refs_table(&refs_table); if (show_pinned) - delete_pinned_obj_table(&link_table); + delete_pinned_obj_table(link_table); return errno == ENOENT ? 0 : -1; } diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index baf607c..0d64e39 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -14,6 +14,7 @@ #include #include +#include #include #include "json_writer.h" @@ -105,16 +106,6 @@ void set_max_rlimit(void); int mount_tracefs(const char *target); -struct pinned_obj_table { - DECLARE_HASHTABLE(table, 16); -}; - -struct pinned_obj { - __u32 id; - char *path; - struct hlist_node hash; -}; - struct obj_refs_table { DECLARE_HASHTABLE(table, 16); }; @@ -134,9 +125,9 @@ struct obj_refs { struct btf; struct bpf_line_info; -int build_pinned_obj_table(struct pinned_obj_table *table, +int build_pinned_obj_table(struct hashmap *table, enum bpf_obj_type type); -void delete_pinned_obj_table(struct pinned_obj_table *tab); +void delete_pinned_obj_table(struct hashmap *table); __weak int build_obj_refs_table(struct obj_refs_table *table, enum bpf_obj_type type); __weak void delete_obj_refs_table(struct obj_refs_table *table); @@ -256,4 +247,18 @@ int do_filter_dump(struct tcmsg *ifinfo, struct nlattr **tb, const char *kind, int print_all_levels(__maybe_unused enum libbpf_print_level level, const char *format, va_list args); + +size_t hash_fn_for_key_as_id(const void *key, void *ctx); +bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx); + +static inline void *u32_as_hash_field(__u32 x) +{ + return (void *)(uintptr_t)x; +} + +static inline bool hashmap__empty(struct hashmap *map) +{ + return map ? hashmap__size(map) == 0 : true; +} + #endif diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 0085039..2647603 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -17,6 +17,7 @@ #include #include +#include #include "json_writer.h" #include "main.h" @@ -56,7 +57,7 @@ const char * const map_type_name[] = { const size_t map_type_name_size = ARRAY_SIZE(map_type_name); -static struct pinned_obj_table map_table; +static struct hashmap *map_table; static bool map_is_per_cpu(__u32 type) { @@ -537,15 +538,14 @@ static int show_map_close_json(int fd, struct bpf_map_info *info) if (info->btf_id) jsonw_int_field(json_wtr, "btf_id", info->btf_id); - if (!hash_empty(map_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(map_table)) { + struct hashmap_entry *entry; jsonw_name(json_wtr, "pinned"); jsonw_start_array(json_wtr); - hash_for_each_possible(map_table.table, obj, hash, info->id) { - if (obj->id == info->id) - jsonw_string(json_wtr, obj->path); - } + hashmap__for_each_key_entry(map_table, entry, + u32_as_hash_field(info->id)) + jsonw_string(json_wtr, entry->value); jsonw_end_array(json_wtr); } @@ -612,13 +612,12 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info) } close(fd); - if (!hash_empty(map_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(map_table)) { + struct hashmap_entry *entry; - hash_for_each_possible(map_table.table, obj, hash, info->id) { - if (obj->id == info->id) - printf("\n\tpinned %s", obj->path); - } + hashmap__for_each_key_entry(map_table, entry, + u32_as_hash_field(info->id)) + printf("\n\tpinned %s", (char *)entry->value); } printf("\n"); @@ -697,8 +696,13 @@ static int do_show(int argc, char **argv) int fd; if (show_pinned) { - hash_init(map_table.table); - build_pinned_obj_table(&map_table, BPF_OBJ_MAP); + map_table = hashmap__new(hash_fn_for_key_as_id, + equal_fn_for_key_as_id, NULL); + if (!map_table) { + p_err("failed to create hashmap for pinned paths"); + return -1; + } + build_pinned_obj_table(map_table, BPF_OBJ_MAP); } build_obj_refs_table(&refs_table, BPF_OBJ_MAP); @@ -747,7 +751,7 @@ static int do_show(int argc, char **argv) delete_obj_refs_table(&refs_table); if (show_pinned) - delete_pinned_obj_table(&map_table); + delete_pinned_obj_table(map_table); return errno == ENOENT ? 0 : -1; } diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 48c2fa4..8fce78c 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -24,6 +24,7 @@ #include #include +#include #include #include @@ -84,7 +85,7 @@ static const char * const attach_type_strings[] = { [__MAX_BPF_ATTACH_TYPE] = NULL, }; -static struct pinned_obj_table prog_table; +static struct hashmap *prog_table; static enum bpf_attach_type parse_attach_type(const char *str) { @@ -418,15 +419,14 @@ static void print_prog_json(struct bpf_prog_info *info, int fd) if (info->btf_id) jsonw_int_field(json_wtr, "btf_id", info->btf_id); - if (!hash_empty(prog_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(prog_table)) { + struct hashmap_entry *entry; jsonw_name(json_wtr, "pinned"); jsonw_start_array(json_wtr); - hash_for_each_possible(prog_table.table, obj, hash, info->id) { - if (obj->id == info->id) - jsonw_string(json_wtr, obj->path); - } + hashmap__for_each_key_entry(prog_table, entry, + u32_as_hash_field(info->id)) + jsonw_string(json_wtr, entry->value); jsonw_end_array(json_wtr); } @@ -490,13 +490,12 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd) if (info->nr_map_ids) show_prog_maps(fd, info->nr_map_ids); - if (!hash_empty(prog_table.table)) { - struct pinned_obj *obj; + if (!hashmap__empty(prog_table)) { + struct hashmap_entry *entry; - hash_for_each_possible(prog_table.table, obj, hash, info->id) { - if (obj->id == info->id) - printf("\n\tpinned %s", obj->path); - } + hashmap__for_each_key_entry(prog_table, entry, + u32_as_hash_field(info->id)) + printf("\n\tpinned %s", (char *)entry->value); } if (info->btf_id) @@ -570,8 +569,13 @@ static int do_show(int argc, char **argv) int fd; if (show_pinned) { - hash_init(prog_table.table); - build_pinned_obj_table(&prog_table, BPF_OBJ_PROG); + prog_table = hashmap__new(hash_fn_for_key_as_id, + equal_fn_for_key_as_id, NULL); + if (!prog_table) { + p_err("failed to create hashmap for pinned paths"); + return -1; + } + build_pinned_obj_table(prog_table, BPF_OBJ_PROG); } build_obj_refs_table(&refs_table, BPF_OBJ_PROG); @@ -618,7 +622,7 @@ static int do_show(int argc, char **argv) delete_obj_refs_table(&refs_table); if (show_pinned) - delete_pinned_obj_table(&prog_table); + delete_pinned_obj_table(prog_table); return err; } -- 2.7.4