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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 <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211023205154.6710-4-quentin@isovalent.com
This commit is contained in:
Quentin Monnet
Andrii Nakryiko
parent
46241271d1
commit
8f184732b6
6 changed files with 111 additions and 84 deletions
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@ -31,9 +31,9 @@ LIBBPF = $(LIBBPF_OUTPUT)libbpf.a
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LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/
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LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a
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# We need to copy nlattr.h which is not otherwise exported by libbpf, but still
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# required by bpftool.
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LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,nlattr.h)
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# We need to copy hashmap.h and nlattr.h which is not otherwise exported by
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# libbpf, but still required by bpftool.
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LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h)
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ifeq ($(BPFTOOL_VERSION),)
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BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
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@ -209,7 +209,7 @@ $(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP)
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$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
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$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
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$(BOOTSTRAP_OUTPUT)%.o: %.c | $(BOOTSTRAP_OUTPUT)
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$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT)
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$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<
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$(OUTPUT)%.o: %.c
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@ -22,6 +22,7 @@
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#include <sys/vfs.h>
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#include <bpf/bpf.h>
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#include <bpf/hashmap.h>
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#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
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#include "main.h"
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@ -393,7 +394,7 @@ void print_hex_data_json(uint8_t *data, size_t len)
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}
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/* extra params for nftw cb */
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static struct pinned_obj_table *build_fn_table;
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static struct hashmap *build_fn_table;
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static enum bpf_obj_type build_fn_type;
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static int do_build_table_cb(const char *fpath, const struct stat *sb,
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@ -401,9 +402,9 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb,
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{
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struct bpf_prog_info pinned_info;
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__u32 len = sizeof(pinned_info);
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struct pinned_obj *obj_node;
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enum bpf_obj_type objtype;
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int fd, err = 0;
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char *path;
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if (typeflag != FTW_F)
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goto out_ret;
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@ -420,28 +421,26 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb,
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if (bpf_obj_get_info_by_fd(fd, &pinned_info, &len))
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goto out_close;
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obj_node = calloc(1, sizeof(*obj_node));
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if (!obj_node) {
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path = strdup(fpath);
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if (!path) {
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err = -1;
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goto out_close;
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}
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obj_node->id = pinned_info.id;
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obj_node->path = strdup(fpath);
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if (!obj_node->path) {
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err = -1;
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free(obj_node);
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err = hashmap__append(build_fn_table, u32_as_hash_field(pinned_info.id), path);
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if (err) {
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p_err("failed to append entry to hashmap for ID %u, path '%s': %s",
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pinned_info.id, path, strerror(errno));
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goto out_close;
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}
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hash_add(build_fn_table->table, &obj_node->hash, obj_node->id);
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out_close:
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close(fd);
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out_ret:
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return err;
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}
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int build_pinned_obj_table(struct pinned_obj_table *tab,
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int build_pinned_obj_table(struct hashmap *tab,
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enum bpf_obj_type type)
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{
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struct mntent *mntent = NULL;
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@ -470,17 +469,18 @@ int build_pinned_obj_table(struct pinned_obj_table *tab,
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return err;
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}
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void delete_pinned_obj_table(struct pinned_obj_table *tab)
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void delete_pinned_obj_table(struct hashmap *map)
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{
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struct pinned_obj *obj;
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struct hlist_node *tmp;
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unsigned int bkt;
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struct hashmap_entry *entry;
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size_t bkt;
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hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
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hash_del(&obj->hash);
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free(obj->path);
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free(obj);
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}
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if (!map)
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return;
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hashmap__for_each_entry(map, entry, bkt)
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free(entry->value);
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hashmap__free(map);
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}
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unsigned int get_page_size(void)
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@ -962,3 +962,13 @@ int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len)
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return fd;
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}
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size_t hash_fn_for_key_as_id(const void *key, void *ctx)
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{
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return (size_t)key;
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}
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bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx)
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{
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return k1 == k2;
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}
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@ -7,6 +7,7 @@
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#include <unistd.h>
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#include <bpf/bpf.h>
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#include <bpf/hashmap.h>
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#include "json_writer.h"
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#include "main.h"
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@ -20,7 +21,7 @@ static const char * const link_type_name[] = {
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[BPF_LINK_TYPE_NETNS] = "netns",
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};
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static struct pinned_obj_table link_table;
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static struct hashmap *link_table;
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static int link_parse_fd(int *argc, char ***argv)
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{
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@ -158,15 +159,14 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
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break;
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}
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if (!hash_empty(link_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(link_table)) {
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struct hashmap_entry *entry;
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jsonw_name(json_wtr, "pinned");
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jsonw_start_array(json_wtr);
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hash_for_each_possible(link_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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jsonw_string(json_wtr, obj->path);
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}
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hashmap__for_each_key_entry(link_table, entry,
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u32_as_hash_field(info->id))
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jsonw_string(json_wtr, entry->value);
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jsonw_end_array(json_wtr);
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}
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@ -246,13 +246,12 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
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break;
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}
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if (!hash_empty(link_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(link_table)) {
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struct hashmap_entry *entry;
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hash_for_each_possible(link_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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printf("\n\tpinned %s", obj->path);
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}
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hashmap__for_each_key_entry(link_table, entry,
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u32_as_hash_field(info->id))
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printf("\n\tpinned %s", (char *)entry->value);
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}
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emit_obj_refs_plain(&refs_table, info->id, "\n\tpids ");
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@ -305,8 +304,13 @@ static int do_show(int argc, char **argv)
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int err, fd;
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if (show_pinned) {
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hash_init(link_table.table);
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build_pinned_obj_table(&link_table, BPF_OBJ_LINK);
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link_table = hashmap__new(hash_fn_for_key_as_id,
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equal_fn_for_key_as_id, NULL);
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if (!link_table) {
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p_err("failed to create hashmap for pinned paths");
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return -1;
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}
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build_pinned_obj_table(link_table, BPF_OBJ_LINK);
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}
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build_obj_refs_table(&refs_table, BPF_OBJ_LINK);
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@ -351,7 +355,7 @@ static int do_show(int argc, char **argv)
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delete_obj_refs_table(&refs_table);
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if (show_pinned)
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delete_pinned_obj_table(&link_table);
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delete_pinned_obj_table(link_table);
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return errno == ENOENT ? 0 : -1;
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}
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@ -14,6 +14,7 @@
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#include <linux/hashtable.h>
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#include <tools/libc_compat.h>
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#include <bpf/hashmap.h>
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#include <bpf/libbpf.h>
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#include "json_writer.h"
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@ -105,16 +106,6 @@ void set_max_rlimit(void);
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int mount_tracefs(const char *target);
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struct pinned_obj_table {
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DECLARE_HASHTABLE(table, 16);
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};
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struct pinned_obj {
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__u32 id;
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char *path;
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struct hlist_node hash;
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};
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struct obj_refs_table {
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DECLARE_HASHTABLE(table, 16);
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};
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@ -134,9 +125,9 @@ struct obj_refs {
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struct btf;
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struct bpf_line_info;
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int build_pinned_obj_table(struct pinned_obj_table *table,
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int build_pinned_obj_table(struct hashmap *table,
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enum bpf_obj_type type);
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void delete_pinned_obj_table(struct pinned_obj_table *tab);
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void delete_pinned_obj_table(struct hashmap *table);
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__weak int build_obj_refs_table(struct obj_refs_table *table,
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enum bpf_obj_type type);
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__weak void delete_obj_refs_table(struct obj_refs_table *table);
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@ -256,4 +247,18 @@ int do_filter_dump(struct tcmsg *ifinfo, struct nlattr **tb, const char *kind,
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int print_all_levels(__maybe_unused enum libbpf_print_level level,
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const char *format, va_list args);
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size_t hash_fn_for_key_as_id(const void *key, void *ctx);
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bool equal_fn_for_key_as_id(const void *k1, const void *k2, void *ctx);
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static inline void *u32_as_hash_field(__u32 x)
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{
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return (void *)(uintptr_t)x;
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}
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static inline bool hashmap__empty(struct hashmap *map)
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{
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return map ? hashmap__size(map) == 0 : true;
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}
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#endif
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@ -17,6 +17,7 @@
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#include <bpf/bpf.h>
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#include <bpf/btf.h>
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#include <bpf/hashmap.h>
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#include "json_writer.h"
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#include "main.h"
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@ -56,7 +57,7 @@ const char * const map_type_name[] = {
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const size_t map_type_name_size = ARRAY_SIZE(map_type_name);
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static struct pinned_obj_table map_table;
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static struct hashmap *map_table;
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static bool map_is_per_cpu(__u32 type)
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{
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@ -537,15 +538,14 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
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if (info->btf_id)
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jsonw_int_field(json_wtr, "btf_id", info->btf_id);
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if (!hash_empty(map_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(map_table)) {
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struct hashmap_entry *entry;
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jsonw_name(json_wtr, "pinned");
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jsonw_start_array(json_wtr);
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hash_for_each_possible(map_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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jsonw_string(json_wtr, obj->path);
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}
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hashmap__for_each_key_entry(map_table, entry,
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u32_as_hash_field(info->id))
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jsonw_string(json_wtr, entry->value);
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jsonw_end_array(json_wtr);
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}
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@ -612,13 +612,12 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info)
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}
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close(fd);
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if (!hash_empty(map_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(map_table)) {
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struct hashmap_entry *entry;
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hash_for_each_possible(map_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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printf("\n\tpinned %s", obj->path);
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}
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hashmap__for_each_key_entry(map_table, entry,
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u32_as_hash_field(info->id))
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printf("\n\tpinned %s", (char *)entry->value);
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}
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printf("\n");
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@ -697,8 +696,13 @@ static int do_show(int argc, char **argv)
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int fd;
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if (show_pinned) {
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hash_init(map_table.table);
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build_pinned_obj_table(&map_table, BPF_OBJ_MAP);
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map_table = hashmap__new(hash_fn_for_key_as_id,
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equal_fn_for_key_as_id, NULL);
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if (!map_table) {
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p_err("failed to create hashmap for pinned paths");
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return -1;
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}
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build_pinned_obj_table(map_table, BPF_OBJ_MAP);
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}
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build_obj_refs_table(&refs_table, BPF_OBJ_MAP);
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@ -747,7 +751,7 @@ static int do_show(int argc, char **argv)
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delete_obj_refs_table(&refs_table);
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if (show_pinned)
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delete_pinned_obj_table(&map_table);
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delete_pinned_obj_table(map_table);
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return errno == ENOENT ? 0 : -1;
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}
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@ -24,6 +24,7 @@
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#include <bpf/bpf.h>
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#include <bpf/btf.h>
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#include <bpf/hashmap.h>
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#include <bpf/libbpf.h>
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#include <bpf/skel_internal.h>
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@ -84,7 +85,7 @@ static const char * const attach_type_strings[] = {
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[__MAX_BPF_ATTACH_TYPE] = NULL,
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};
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static struct pinned_obj_table prog_table;
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static struct hashmap *prog_table;
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static enum bpf_attach_type parse_attach_type(const char *str)
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{
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@ -418,15 +419,14 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
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if (info->btf_id)
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jsonw_int_field(json_wtr, "btf_id", info->btf_id);
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if (!hash_empty(prog_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(prog_table)) {
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struct hashmap_entry *entry;
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jsonw_name(json_wtr, "pinned");
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jsonw_start_array(json_wtr);
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hash_for_each_possible(prog_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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jsonw_string(json_wtr, obj->path);
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}
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hashmap__for_each_key_entry(prog_table, entry,
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u32_as_hash_field(info->id))
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jsonw_string(json_wtr, entry->value);
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jsonw_end_array(json_wtr);
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}
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@ -490,13 +490,12 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
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if (info->nr_map_ids)
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show_prog_maps(fd, info->nr_map_ids);
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if (!hash_empty(prog_table.table)) {
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struct pinned_obj *obj;
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if (!hashmap__empty(prog_table)) {
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struct hashmap_entry *entry;
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hash_for_each_possible(prog_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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printf("\n\tpinned %s", obj->path);
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}
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hashmap__for_each_key_entry(prog_table, entry,
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u32_as_hash_field(info->id))
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printf("\n\tpinned %s", (char *)entry->value);
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}
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if (info->btf_id)
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@ -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;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue