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bpftool: Adding support for BTF program names

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`bpftool prog list` and other bpftool subcommands that show
BPF program names currently get them from bpf_prog_info.name.
That field is limited to 16 (BPF_OBJ_NAME_LEN) chars which leads
to truncated names since many progs have much longer names.

The idea of this change is to improve all bpftool commands that
output prog name so that bpftool uses info from BTF to print
program names if available.

It tries bpf_prog_info.name first and fall back to btf only if
the name is suspected to be truncated (has 15 chars length).

Right now `bpftool p show id <id>` returns capped prog name

<id>: kprobe  name example_cap_cap  tag 712e...
...

With this change it would return

<id>: kprobe  name example_cap_capable  tag 712e...
...

Note, other commands that print prog names (e.g. "bpftool
cgroup tree") are also addressed in this change.

Signed-off-by: Raman Shukhau <ramasha@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220119100255.1068997-1-ramasha@fb.com
This commit is contained in:
Raman Shukhau
2022-01-19 02:02:55 -08:00
committed by Andrii Nakryiko
parent eaa266d83a
commit b662000aff
4 changed files with 70 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
tools/bpf/bpftool/prog.c
View File

@ -424,8 +424,10 @@ out_free:
free(value);
}
static void print_prog_header_json(struct bpf_prog_info *info)
static void print_prog_header_json(struct bpf_prog_info *info, int fd)
{
char prog_name[MAX_PROG_FULL_NAME];
jsonw_uint_field(json_wtr, "id", info->id);
if (info->type < ARRAY_SIZE(prog_type_name))
jsonw_string_field(json_wtr, "type",
@ -433,8 +435,10 @@ static void print_prog_header_json(struct bpf_prog_info *info)
else
jsonw_uint_field(json_wtr, "type", info->type);
if (*info->name)
jsonw_string_field(json_wtr, "name", info->name);
if (*info->name) {
get_prog_full_name(info, fd, prog_name, sizeof(prog_name));
jsonw_string_field(json_wtr, "name", prog_name);
}
jsonw_name(json_wtr, "tag");
jsonw_printf(json_wtr, "\"" BPF_TAG_FMT "\"",
@ -455,7 +459,7 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
char *memlock;
jsonw_start_object(json_wtr);
print_prog_header_json(info);
print_prog_header_json(info, fd);
print_dev_json(info->ifindex, info->netns_dev, info->netns_ino);
if (info->load_time) {
@ -507,16 +511,20 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
jsonw_end_object(json_wtr);
}
static void print_prog_header_plain(struct bpf_prog_info *info)
static void print_prog_header_plain(struct bpf_prog_info *info, int fd)
{
char prog_name[MAX_PROG_FULL_NAME];
printf("%u: ", info->id);
if (info->type < ARRAY_SIZE(prog_type_name))
printf("%s ", prog_type_name[info->type]);
else
printf("type %u ", info->type);
if (*info->name)
printf("name %s ", info->name);
if (*info->name) {
get_prog_full_name(info, fd, prog_name, sizeof(prog_name));
printf("name %s ", prog_name);
}
printf("tag ");
fprint_hex(stdout, info->tag, BPF_TAG_SIZE, "");
@ -534,7 +542,7 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
{
char *memlock;
print_prog_header_plain(info);
print_prog_header_plain(info, fd);
if (info->load_time) {
char buf[32];
@ -972,10 +980,10 @@ static int do_dump(int argc, char **argv)
if (json_output && nb_fds > 1) {
jsonw_start_object(json_wtr); /* prog object */
print_prog_header_json(&info);
print_prog_header_json(&info, fds[i]);
jsonw_name(json_wtr, "insns");
} else if (nb_fds > 1) {
print_prog_header_plain(&info);
print_prog_header_plain(&info, fds[i]);
}
err = prog_dump(&info, mode, filepath, opcodes, visual, linum);