2022-11-01 14:49:11

by Tao Chen

Subject: [PATCH] bpftool: Support use full prog name in prog subcommand

Now that the commit: <b662000aff84> ("bpftool: Adding support for BTF
program names") supported show the full prog name, we can also use
the full prog name more than 16 (BPF_OBJ_NAME_LEN) chars in prog
subcommand, such as "bpftool prog show name PROG_NAME".

Signed-off-by: Tao Chen <[email protected]>
---
tools/bpf/bpftool/common.c | 48 ++++++++++++++++++++++++++++++++++++++--------
1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 067e9ea..5efdedc 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -720,6 +720,40 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
return vfprintf(stderr, format, args);
}

+static bool is_invalid_prog(char *nametag, struct bpf_prog_info *info,
+ struct bpf_func_info *finfo, bool tag)
+{
+ const struct btf *prog_btf;
+ const struct btf_type *func_type;
+ const char *name;
+
+ if (tag)
+ return memcmp(nametag, info->tag, BPF_TAG_SIZE);
+
+ if (strlen(nametag) < BPF_OBJ_NAME_LEN)
+ return strncmp(nametag, info->name, BPF_OBJ_NAME_LEN);
+
+ prog_btf = btf__load_from_kernel_by_id(info->btf_id);
+ if (!prog_btf) {
+ p_err("get prog btf failed, btf_id:%u\n", info->btf_id);
+ return true;
+ }
+
+ func_type = btf__type_by_id(prog_btf, finfo->type_id);
+ if (!func_type || !btf_is_func(func_type)) {
+ p_err("func type invalid, type_id:%u\n", finfo->type_id);
+ return true;
+ }
+
+ name = btf__name_by_offset(prog_btf, func_type->name_off);
+ if (!name) {
+ p_err("func name invalid, name_off:%u\n", func_type->name_off);
+ return true;
+ }
+
+ return strncmp(nametag, name, strlen(name));
+}
+
static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
{
unsigned int id = 0;
@@ -729,6 +763,7 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)

while (true) {
struct bpf_prog_info info = {};
+ struct bpf_func_info finfo = {};
__u32 len = sizeof(info);

err = bpf_prog_get_next_id(id, &id);
@@ -747,15 +782,17 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
goto err_close_fds;
}

+ info.nr_func_info = 1;
+ info.func_info_rec_size = sizeof(finfo);
+ info.func_info = ptr_to_u64(&finfo);
+
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get prog info (%u): %s",
id, strerror(errno));
goto err_close_fd;
}
-
- if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
- (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
+ if (is_invalid_prog(nametag, &info, &finfo, tag)) {
close(fd);
continue;
}
@@ -818,12 +855,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
char *name;

NEXT_ARGP();
-
name = **argv;
- if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
- p_err("can't parse name");
- return -1;
- }
NEXT_ARGP();

return prog_fd_by_nametag(name, fds, false);
--
2.2.1

2022-11-01 16:47:20

by Daniel Borkmann

Subject: Re: [PATCH] bpftool: Support use full prog name in prog subcommand

On 11/1/22 3:38 PM, Tao Chen wrote:
> Now that the commit: <b662000aff84> ("bpftool: Adding support for BTF
> program names") supported show the full prog name, we can also use
> the full prog name more than 16 (BPF_OBJ_NAME_LEN) chars in prog
> subcommand, such as "bpftool prog show name PROG_NAME".
>
> Signed-off-by: Tao Chen <[email protected]>

Please rebase against bpf-next, this does not apply cleanly.

2022-11-02 02:37:35

by Tao Chen

Subject: Re: [PATCH] bpftool: Support use full prog name in prog subcommand

在 2022/11/2 上午12:02, Daniel Borkmann 写道:
> On 11/1/22 3:38 PM, Tao Chen wrote:
>> Now that the commit: <b662000aff84> ("bpftool: Adding support for BTF
>> program names") supported show the full prog name, we can also use
>> the full prog name more than 16 (BPF_OBJ_NAME_LEN) chars in prog
>> subcommand, such as "bpftool prog show name PROG_NAME".
>>
>> Signed-off-by: Tao Chen <[email protected]>
>
> Please rebase against bpf-next, this does not apply cleanly.
Ok, i will resend it, thank you!