From a20693b6e72e59fb9b896193df0f8007693447d0 Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Thu, 10 Sep 2020 11:26:50 +0100 Subject: [PATCH] tools: bpftool: Clean up function to dump map entry The function used to dump a map entry in bpftool is a bit difficult to follow, as a consequence to earlier refactorings. There is a variable ("num_elems") which does not appear to be necessary, and the error handling would look cleaner if moved to its own function. Let's clean it up. No functional change. v2: - v1 was erroneously removing the check on fd maps in an attempt to get support for outer map dumps. This is already working. Instead, v2 focuses on cleaning up the dump_map_elem() function, to avoid similar confusion in the future. Signed-off-by: Quentin Monnet Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200910102652.10509-2-quentin@isovalent.com --- tools/bpf/bpftool/map.c | 101 +++++++++++++++++++++++++----------------------- 1 file changed, 52 insertions(+), 49 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index bc0071228f88..c8159cb4fb1e 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -213,8 +213,9 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key, jsonw_end_object(json_wtr); } -static void print_entry_error(struct bpf_map_info *info, unsigned char *key, - const char *error_msg) +static void +print_entry_error_msg(struct bpf_map_info *info, unsigned char *key, + const char *error_msg) { int msg_size = strlen(error_msg); bool single_line, break_names; @@ -232,6 +233,40 @@ static void print_entry_error(struct bpf_map_info *info, unsigned char *key, printf("\n"); } +static void +print_entry_error(struct bpf_map_info *map_info, void *key, int lookup_errno) +{ + /* For prog_array maps or arrays of maps, failure to lookup the value + * means there is no entry for that key. Do not print an error message + * in that case. + */ + if (map_is_map_of_maps(map_info->type) || + map_is_map_of_progs(map_info->type)) + return; + + if (json_output) { + jsonw_start_object(json_wtr); /* entry */ + jsonw_name(json_wtr, "key"); + print_hex_data_json(key, map_info->key_size); + jsonw_name(json_wtr, "value"); + jsonw_start_object(json_wtr); /* error */ + jsonw_string_field(json_wtr, "error", strerror(lookup_errno)); + jsonw_end_object(json_wtr); /* error */ + jsonw_end_object(json_wtr); /* entry */ + } else { + const char *msg = NULL; + + if (lookup_errno == ENOENT) + msg = ""; + else if (lookup_errno == ENOSPC && + map_info->type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) + msg = ""; + + print_entry_error_msg(map_info, key, + msg ? : strerror(lookup_errno)); + } +} + static void print_entry_plain(struct bpf_map_info *info, unsigned char *key, unsigned char *value) { @@ -713,56 +748,23 @@ static int dump_map_elem(int fd, void *key, void *value, struct bpf_map_info *map_info, struct btf *btf, json_writer_t *btf_wtr) { - int num_elems = 0; - int lookup_errno; - - if (!bpf_map_lookup_elem(fd, key, value)) { - if (json_output) { - print_entry_json(map_info, key, value, btf); - } else { - if (btf) { - struct btf_dumper d = { - .btf = btf, - .jw = btf_wtr, - .is_plain_text = true, - }; - - do_dump_btf(&d, map_info, key, value); - } else { - print_entry_plain(map_info, key, value); - } - num_elems++; - } - return num_elems; + if (bpf_map_lookup_elem(fd, key, value)) { + print_entry_error(map_info, key, errno); + return -1; } - /* lookup error handling */ - lookup_errno = errno; - - if (map_is_map_of_maps(map_info->type) || - map_is_map_of_progs(map_info->type)) - return 0; - if (json_output) { - jsonw_start_object(json_wtr); - jsonw_name(json_wtr, "key"); - print_hex_data_json(key, map_info->key_size); - jsonw_name(json_wtr, "value"); - jsonw_start_object(json_wtr); - jsonw_string_field(json_wtr, "error", strerror(lookup_errno)); - jsonw_end_object(json_wtr); - jsonw_end_object(json_wtr); - } else { - const char *msg = NULL; - - if (lookup_errno == ENOENT) - msg = ""; - else if (lookup_errno == ENOSPC && - map_info->type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) - msg = ""; + print_entry_json(map_info, key, value, btf); + } else if (btf) { + struct btf_dumper d = { + .btf = btf, + .jw = btf_wtr, + .is_plain_text = true, + }; - print_entry_error(map_info, key, - msg ? : strerror(lookup_errno)); + do_dump_btf(&d, map_info, key, value); + } else { + print_entry_plain(map_info, key, value); } return 0; @@ -873,7 +875,8 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, err = 0; break; } - num_elems += dump_map_elem(fd, key, value, info, btf, wtr); + if (!dump_map_elem(fd, key, value, info, btf, wtr)) + num_elems++; prev_key = key; } -- 2.11.0