From 8f184732b60b74a8f8ba0d9a5c248bf611b1ebba Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Sat, 23 Oct 2021 21:51:52 +0100 Subject: 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/common.c | 50 +++++++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 20 deletions(-) (limited to 'tools/bpf/bpftool/common.c') diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index d42d930a3ec4..511eccdbdfe6 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; +} -- cgit v1.2.3