From: Quentin Monnet <quentin@isovalent.com>
Date: Sat, 23 Oct 2021 21:51:52 +0100
Subject: bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects
Patch-mainline: v5.16-rc1
Git-commit: 8f184732b60b74a8f8ba0d9a5c248bf611b1ebba
References: jsc#PED-1377
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 <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211023205154.6710-4-quentin@isovalent.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/bpf/bpftool/Makefile | 8 +++---
tools/bpf/bpftool/common.c | 52 ++++++++++++++++++++++++++-------------------
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, 112 insertions(+), 85 deletions(-)
--- 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)
$(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
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -22,6 +22,7 @@
#include <sys/vfs.h>
#include <bpf/bpf.h>
+#include <bpf/hashmap.h>
#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
#include "main.h"
@@ -393,7 +394,7 @@ void print_hex_data_json(uint8_t *data,
}
/* 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
{
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
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
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;
-
- hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
- hash_del(&obj->hash);
- free(obj->path);
- free(obj);
- }
+ struct hashmap_entry *entry;
+ size_t bkt;
+
+ 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, cha
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;
+}
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -7,6 +7,7 @@
#include <unistd.h>
#include <bpf/bpf.h>
+#include <bpf/hashmap.h>
#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,
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,
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;
}
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -14,6 +14,7 @@
#include <linux/hashtable.h>
#include <tools/libc_compat.h>
+#include <bpf/hashmap.h>
#include <bpf/libbpf.h>
#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,
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
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -17,6 +17,7 @@
#include <bpf/bpf.h>
#include <bpf/btf.h>
+#include <bpf/hashmap.h>
#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, s
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,
}
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;
}
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -24,6 +24,7 @@
#include <bpf/bpf.h>
#include <bpf/btf.h>
+#include <bpf/hashmap.h>
#include <bpf/libbpf.h>
#include <bpf/skel_internal.h>
@@ -84,7 +85,7 @@ static const char * const attach_type_st
[__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_p
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_
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;
}