[PATCH bpf-next 1/2] bpftool: Add bpf_token show

[PATCH bpf-next 1/2] bpftool: Add bpf_token show

[Tao Chen]

Add `bpftool token show` command to get token info
from bpf fs in /proc/mounts.

Example plain output for `token show`:
token_info:
        /sys/fs/bpf/token

allowed_cmds:
        map_create          prog_load

allowed_maps:

allowed_progs:
        kprobe

allowed_attachs:
        xdp

Example json output for `token show`:
{
    "token_info": "/sys/fs/bpf/token",
    "allowed_cmds": ["map_create","prog_load"
    ],
    "allowed_maps":
    "allowed_progs": ["kprobe"
    ],
    "allowed_attachs": ["xdp"
    ]
}

Signed-off-by: Tao Chen <chen.dylane@linux.dev>
---
 tools/bpf/bpftool/main.c  |   3 +-
 tools/bpf/bpftool/main.h  |   1 +
 tools/bpf/bpftool/token.c | 229 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+), 1 deletion(-)
 create mode 100644 tools/bpf/bpftool/token.c

diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 2b7f2bd3a7d..0f1183b2ed0 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -61,7 +61,7 @@ static int do_help(int argc, char **argv)
 		"       %s batch file FILE\n"
 		"       %s version\n"
 		"\n"
-		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
+		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter | token }\n"
 		"       " HELP_SPEC_OPTIONS " |\n"
 		"                    {-V|--version} }\n"
 		"",
@@ -87,6 +87,7 @@ static const struct cmd commands[] = {
 	{ "gen",	do_gen },
 	{ "struct_ops",	do_struct_ops },
 	{ "iter",	do_iter },
+	{ "token",	do_token },
 	{ "version",	do_version },
 	{ 0 }
 };
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 6db704fda5c..a2bb0714b3d 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -166,6 +166,7 @@ int do_tracelog(int argc, char **arg) __weak;
 int do_feature(int argc, char **argv) __weak;
 int do_struct_ops(int argc, char **argv) __weak;
 int do_iter(int argc, char **argv) __weak;
+int do_token(int argc, char **argv) __weak;
 
 int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
 int prog_parse_fd(int *argc, char ***argv);
diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
new file mode 100644
index 00000000000..2fcaff4f2ba
--- /dev/null
+++ b/tools/bpf/bpftool/token.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <mntent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "json_writer.h"
+#include "main.h"
+
+#define MOUNTS_FILE "/proc/mounts"
+
+#define zclose(fd) do { if (fd >= 0) close(fd); fd = -1; } while (0)
+
+static bool has_delegate_options(const char *mnt_ops)
+{
+	return strstr(mnt_ops, "delegate_cmds") != NULL ||
+	       strstr(mnt_ops, "delegate_maps") != NULL ||
+	       strstr(mnt_ops, "delegate_progs") != NULL ||
+	       strstr(mnt_ops, "delegate_attachs") != NULL;
+}
+
+static char *get_delegate_value(const char *opts, const char *key)
+{
+	char *token, *rest, *ret = NULL;
+	char *opts_copy = strdup(opts);
+
+	if (!opts_copy)
+		return NULL;
+
+	for (token = strtok_r(opts_copy, ",", &rest); token != NULL;
+			token = strtok_r(NULL, ",", &rest)) {
+		if (strncmp(token, key, strlen(key)) == 0 &&
+				token[strlen(key)] == '=') {
+			ret = token + strlen(key) + 1;
+			break;
+		}
+	}
+	free(opts_copy);
+
+	return ret;
+}
+
+static void print_items_per_line(const char *input, int items_per_line)
+{
+	char *str, *rest;
+	int cnt = 0;
+	char *strs = strdup(input);
+
+	if (!strs)
+		return;
+
+	for (str = strtok_r(strs, ":", &rest); str != NULL;
+			str = strtok_r(NULL, ":", &rest)) {
+		if (cnt % items_per_line == 0)
+			printf("\n\t");
+
+		printf("%-20s", str);
+		cnt++;
+	}
+
+	free(strs);
+}
+
+#define ITEMS_PER_LINE 4
+static void show_token_info_plain(struct mntent *mntent)
+{
+	char *value;
+
+	printf("\ntoken_info:");
+	printf("\n\t%s\n", mntent->mnt_dir);
+
+	printf("\nallowed_cmds:");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
+	if (value)
+		print_items_per_line(value, ITEMS_PER_LINE);
+	printf("\n");
+
+	printf("\nallowed_maps:");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
+	if (value)
+		print_items_per_line(value, ITEMS_PER_LINE);
+	printf("\n");
+
+	printf("\nallowed_progs:");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
+	if (value)
+		print_items_per_line(value, ITEMS_PER_LINE);
+	printf("\n");
+
+	printf("\nallowed_attachs:");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
+	if (value)
+		print_items_per_line(value, ITEMS_PER_LINE);
+	printf("\n");
+}
+
+static void __json_array_str(const char *input)
+{
+	char *str, *rest;
+	char *strs = strdup(input);
+
+	if (!strs)
+		return;
+
+	jsonw_start_array(json_wtr);
+	for (str = strtok_r(strs, ":", &rest); str != NULL;
+			str = strtok_r(NULL, ":", &rest)) {
+		jsonw_string(json_wtr, str);
+	}
+	jsonw_end_array(json_wtr);
+
+	free(strs);
+}
+
+static void show_token_info_json(struct mntent *mntent)
+{
+	char *value;
+
+	jsonw_start_object(json_wtr);
+
+	jsonw_string_field(json_wtr, "token_info", mntent->mnt_dir);
+
+	jsonw_name(json_wtr, "allowed_cmds");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
+	if (value)
+		__json_array_str(value);
+
+	jsonw_name(json_wtr, "allowed_maps");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
+	if (value)
+		__json_array_str(value);
+
+	jsonw_name(json_wtr, "allowed_progs");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
+	if (value)
+		__json_array_str(value);
+
+	jsonw_name(json_wtr, "allowed_attachs");
+	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
+	if (value)
+		__json_array_str(value);
+
+	jsonw_end_object(json_wtr);
+}
+
+static int __show_token_info(struct mntent *mntent)
+{
+
+	if (json_output)
+		show_token_info_json(mntent);
+	else
+		show_token_info_plain(mntent);
+
+	return 0;
+}
+
+static int show_token_info(void)
+{
+	FILE *fp;
+	struct mntent *ent;
+	bool hit = false;
+
+	fp = setmntent(MOUNTS_FILE, "r");
+	if (!fp) {
+		p_err("Failed to open:%s", MOUNTS_FILE);
+		return -1;
+	}
+
+	while ((ent = getmntent(fp)) != NULL) {
+		if (strcmp(ent->mnt_type, "bpf") == 0) {
+			if (has_delegate_options(ent->mnt_opts)) {
+				hit = true;
+				break;
+			}
+		}
+	}
+
+	if (hit)
+		__show_token_info(ent);
+	endmntent(fp);
+
+	return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+	if (argc)
+		return BAD_ARG();
+
+	return show_token_info();
+}
+
+static int do_help(int argc, char **argv)
+{
+	if (json_output) {
+		jsonw_null(json_wtr);
+		return 0;
+	}
+
+	fprintf(stderr,
+		"Usage: %1$s %2$s { show | list }\n"
+		"	%1$s %2$s help\n"
+		"\n"
+		"",
+		bin_name, argv[-2]);
+	return 0;
+}
+
+static const struct cmd cmds[] = {
+	{ "show",	do_show },
+	{ "help",	do_help },
+	{ "list",	do_show },
+	{ 0 }
+};
+
+int do_token(int argc, char **argv)
+{
+	return cmd_select(cmds, argc, argv, do_help);
+}
-- 
2.48.1

[PATCH bpf-next 2/2] bpftool: Add bpftool-token manpage

[Tao Chen]

Add bpftool-token manpage with information and examples of token-related
commands.

Signed-off-by: Tao Chen <chen.dylane@linux.dev>
---
 .../bpftool/Documentation/bpftool-token.rst   | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 tools/bpf/bpftool/Documentation/bpftool-token.rst

diff --git a/tools/bpf/bpftool/Documentation/bpftool-token.rst b/tools/bpf/bpftool/Documentation/bpftool-token.rst
new file mode 100644
index 00000000000..177f93c0bc7
--- /dev/null
+++ b/tools/bpf/bpftool/Documentation/bpftool-token.rst
@@ -0,0 +1,68 @@
+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+================
+bpftool-token
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF progs
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+.. include:: substitutions.rst
+
+SYNOPSIS
+========
+
+**bpftool** [*OPTIONS*] **token** *COMMAND*
+
+*OPTIONS* := { |COMMON_OPTIONS| }
+
+*COMMANDS* := { **show** | **list** | **help** }
+
+TOKEN COMMANDS
+===============
+
+| **bpftool** **token** { **show** | **list** }
+| **bpftool** **token help**
+|
+
+DESCRIPTION
+===========
+bpftool token { show | list }
+    List all the concrete allowed_types for cmds maps progs attachs
+    and the bpffs mount_point used to set the token info.
+
+bpftool prog help
+    Print short help message.
+
+OPTIONS
+========
+.. include:: common_options.rst
+
+EXAMPLES
+========
+|
+| **# mkdir -p /sys/fs/bpf/token**
+| **# mount -t bpf bpffs /sys/fs/bpf/token** \
+|         **-o delegate_cmds=prog_load:map_create** \
+|         **-o delegate_progs=kprobe** \
+|         **-o delegate_attachs=xdp**
+| **# bpftool token list**
+
+::
+
+    token_info:
+            /sys/fs/bpf/token
+
+    allowed_cmds:
+            map_create          prog_load
+
+    allowed_maps:
+
+    allowed_progs:
+            kprobe
+
+    allowed_attachs:
+            xdp
+
-- 
2.48.1

Re: [PATCH bpf-next 2/2] bpftool: Add bpftool-token manpage

[Quentin Monnet]

2025-07-21 01:33 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
> Add bpftool-token manpage with information and examples of token-related
> commands.
> 
> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> ---
>  .../bpftool/Documentation/bpftool-token.rst   | 68 +++++++++++++++++++
>  1 file changed, 68 insertions(+)
>  create mode 100644 tools/bpf/bpftool/Documentation/bpftool-token.rst
> 
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-token.rst b/tools/bpf/bpftool/Documentation/bpftool-token.rst
> new file mode 100644
> index 00000000000..177f93c0bc7
> --- /dev/null
> +++ b/tools/bpf/bpftool/Documentation/bpftool-token.rst
> @@ -0,0 +1,68 @@
> +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +
> +================
> +bpftool-token
> +================
> +-------------------------------------------------------------------------------
> +tool for inspection and simple manipulation of eBPF progs


Copy-pasted from bpftool-prog.rst, please update.


> +-------------------------------------------------------------------------------
> +
> +:Manual section: 8
> +
> +.. include:: substitutions.rst
> +
> +SYNOPSIS
> +========
> +
> +**bpftool** [*OPTIONS*] **token** *COMMAND*
> +
> +*OPTIONS* := { |COMMON_OPTIONS| }
> +
> +*COMMANDS* := { **show** | **list** | **help** }
> +
> +TOKEN COMMANDS
> +===============
> +
> +| **bpftool** **token** { **show** | **list** }
> +| **bpftool** **token help**
> +|
> +
> +DESCRIPTION
> +===========
> +bpftool token { show | list }
> +    List all the concrete allowed_types for cmds maps progs attachs
> +    and the bpffs mount_point used to set the token info.


This is not a summary, please let's use a more verbose description and
avoid abbreviations:

	List all the concrete allowed types for **bpf**\ () system call
	commands, maps, programs, and attach types, as well as the
	*bpffs* mount point used to set the token information.

What is a "concrete" allowed_type?


> +
> +bpftool prog help
> +    Print short help message.
> +
> +OPTIONS
> +========
> +.. include:: common_options.rst
> +
> +EXAMPLES
> +========
> +|
> +| **# mkdir -p /sys/fs/bpf/token**
> +| **# mount -t bpf bpffs /sys/fs/bpf/token** \
> +|         **-o delegate_cmds=prog_load:map_create** \
> +|         **-o delegate_progs=kprobe** \
> +|         **-o delegate_attachs=xdp**
> +| **# bpftool token list**
> +
> +::
> +
> +    token_info:
> +            /sys/fs/bpf/token
> +
> +    allowed_cmds:
> +            map_create          prog_load
> +
> +    allowed_maps:
> +
> +    allowed_progs:
> +            kprobe
> +
> +    allowed_attachs:
> +            xdp
> +


Please also update bpftool's bash completion file. I think it should be:

    diff --git i/tools/bpf/bpftool/bash-completion/bpftool w/tools/bpf/bpftool/bash-completion/bpftool
    index a759ba24471d..3f119d7eae96 100644
    --- i/tools/bpf/bpftool/bash-completion/bpftool
    +++ w/tools/bpf/bpftool/bash-completion/bpftool
    @@ -1215,6 +1215,17 @@ _bpftool()
                         ;;
                 esac
                 ;;
    +        token)
    +            case $command in
    +                show|list)
    +                    return 0
    +                    ;;
    +                *)
    +                    [[ $prev == $object ]] && \
    +                        COMPREPLY=( $( compgen -W 'help show list' -- "$cur" ) )
    +                    ;;
    +            esac
    +            ;;
         esac
     } &&
     complete -F _bpftool bpftool

Re: [PATCH bpf-next 2/2] bpftool: Add bpftool-token manpage

[Tao Chen]

在 2025/7/22 00:23, Quentin Monnet 写道:
> 2025-07-21 01:33 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
>> Add bpftool-token manpage with information and examples of token-related
>> commands.
>>
>> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
>> ---
>>   .../bpftool/Documentation/bpftool-token.rst   | 68 +++++++++++++++++++
>>   1 file changed, 68 insertions(+)
>>   create mode 100644 tools/bpf/bpftool/Documentation/bpftool-token.rst
>>
>> diff --git a/tools/bpf/bpftool/Documentation/bpftool-token.rst b/tools/bpf/bpftool/Documentation/bpftool-token.rst
>> new file mode 100644
>> index 00000000000..177f93c0bc7
>> --- /dev/null
>> +++ b/tools/bpf/bpftool/Documentation/bpftool-token.rst
>> @@ -0,0 +1,68 @@
>> +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +
>> +================
>> +bpftool-token
>> +================
>> +-------------------------------------------------------------------------------
>> +tool for inspection and simple manipulation of eBPF progs
> 
> 
> Copy-pasted from bpftool-prog.rst, please update.
> 

will update it in v2, thanks.

> 
>> +-------------------------------------------------------------------------------
>> +
>> +:Manual section: 8
>> +
>> +.. include:: substitutions.rst
>> +
>> +SYNOPSIS
>> +========
>> +
>> +**bpftool** [*OPTIONS*] **token** *COMMAND*
>> +
>> +*OPTIONS* := { |COMMON_OPTIONS| }
>> +
>> +*COMMANDS* := { **show** | **list** | **help** }
>> +
>> +TOKEN COMMANDS
>> +===============
>> +
>> +| **bpftool** **token** { **show** | **list** }
>> +| **bpftool** **token help**
>> +|
>> +
>> +DESCRIPTION
>> +===========
>> +bpftool token { show | list }
>> +    List all the concrete allowed_types for cmds maps progs attachs
>> +    and the bpffs mount_point used to set the token info.
> 
> 
> This is not a summary, please let's use a more verbose description and
> avoid abbreviations:
> 
> 	List all the concrete allowed types for **bpf**\ () system call
> 	commands, maps, programs, and attach types, as well as the
> 	*bpffs* mount point used to set the token information.
> 
> What is a "concrete" allowed_type?
> 

Uh... I wanted to say speciafic allowed_type, sorry for the poor english.
  > >> +
>> +bpftool prog help
>> +    Print short help message.
>> +
>> +OPTIONS
>> +========
>> +.. include:: common_options.rst
>> +
>> +EXAMPLES
>> +========
>> +|
>> +| **# mkdir -p /sys/fs/bpf/token**
>> +| **# mount -t bpf bpffs /sys/fs/bpf/token** \
>> +|         **-o delegate_cmds=prog_load:map_create** \
>> +|         **-o delegate_progs=kprobe** \
>> +|         **-o delegate_attachs=xdp**
>> +| **# bpftool token list**
>> +
>> +::
>> +
>> +    token_info:
>> +            /sys/fs/bpf/token
>> +
>> +    allowed_cmds:
>> +            map_create          prog_load
>> +
>> +    allowed_maps:
>> +
>> +    allowed_progs:
>> +            kprobe
>> +
>> +    allowed_attachs:
>> +            xdp
>> +
> 
> 
> Please also update bpftool's bash completion file. I think it should be:
> 

will add it in v2.

>      diff --git i/tools/bpf/bpftool/bash-completion/bpftool w/tools/bpf/bpftool/bash-completion/bpftool
>      index a759ba24471d..3f119d7eae96 100644
>      --- i/tools/bpf/bpftool/bash-completion/bpftool
>      +++ w/tools/bpf/bpftool/bash-completion/bpftool
>      @@ -1215,6 +1215,17 @@ _bpftool()
>                           ;;
>                   esac
>                   ;;
>      +        token)
>      +            case $command in
>      +                show|list)
>      +                    return 0
>      +                    ;;
>      +                *)
>      +                    [[ $prev == $object ]] && \
>      +                        COMPREPLY=( $( compgen -W 'help show list' -- "$cur" ) )
>      +                    ;;
>      +            esac
>      +            ;;
>           esac
>       } &&
>       complete -F _bpftool bpftool
> 
-- 
Best Regards
Tao Chen

Re: [PATCH bpf-next 1/2] bpftool: Add bpf_token show

[Quentin Monnet]

Thanks a lot for this!


2025-07-21 01:33 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
> Add `bpftool token show` command to get token info
> from bpf fs in /proc/mounts.
> 
> Example plain output for `token show`:
> token_info:
>         /sys/fs/bpf/token
> 
> allowed_cmds:
>         map_create          prog_load
> 
> allowed_maps:
> 
> allowed_progs:
>         kprobe
> 
> allowed_attachs:
>         xdp
> 
> Example json output for `token show`:
> {
>     "token_info": "/sys/fs/bpf/token",
>     "allowed_cmds": ["map_create","prog_load"
>     ],
>     "allowed_maps":


This is not valid JSON. You're missing a value for "allowed_maps" (here
it should likely be an empty array), and the comma:

	"allowed_maps": [],


>     "allowed_progs": ["kprobe"
>     ],
>     "allowed_attachs": ["xdp"
>     ]
> }
> 
> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> ---
>  tools/bpf/bpftool/main.c  |   3 +-
>  tools/bpf/bpftool/main.h  |   1 +
>  tools/bpf/bpftool/token.c | 229 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 232 insertions(+), 1 deletion(-)
>  create mode 100644 tools/bpf/bpftool/token.c
> 
> diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
> index 2b7f2bd3a7d..0f1183b2ed0 100644
> --- a/tools/bpf/bpftool/main.c
> +++ b/tools/bpf/bpftool/main.c
> @@ -61,7 +61,7 @@ static int do_help(int argc, char **argv)
>  		"       %s batch file FILE\n"
>  		"       %s version\n"
>  		"\n"
> -		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
> +		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter | token }\n"
>  		"       " HELP_SPEC_OPTIONS " |\n"
>  		"                    {-V|--version} }\n"
>  		"",
> @@ -87,6 +87,7 @@ static const struct cmd commands[] = {
>  	{ "gen",	do_gen },
>  	{ "struct_ops",	do_struct_ops },
>  	{ "iter",	do_iter },
> +	{ "token",	do_token },
>  	{ "version",	do_version },
>  	{ 0 }
>  };
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> index 6db704fda5c..a2bb0714b3d 100644
> --- a/tools/bpf/bpftool/main.h
> +++ b/tools/bpf/bpftool/main.h
> @@ -166,6 +166,7 @@ int do_tracelog(int argc, char **arg) __weak;
>  int do_feature(int argc, char **argv) __weak;
>  int do_struct_ops(int argc, char **argv) __weak;
>  int do_iter(int argc, char **argv) __weak;
> +int do_token(int argc, char **argv) __weak;
>  
>  int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
>  int prog_parse_fd(int *argc, char ***argv);
> diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
> new file mode 100644
> index 00000000000..2fcaff4f2ba
> --- /dev/null
> +++ b/tools/bpf/bpftool/token.c
> @@ -0,0 +1,229 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +
> +#ifndef _GNU_SOURCE
> +#define _GNU_SOURCE
> +#endif
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <mntent.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +
> +#include "json_writer.h"
> +#include "main.h"
> +
> +#define MOUNTS_FILE "/proc/mounts"
> +
> +#define zclose(fd) do { if (fd >= 0) close(fd); fd = -1; } while (0)


Seems unused?


> +
> +static bool has_delegate_options(const char *mnt_ops)
> +{
> +	return strstr(mnt_ops, "delegate_cmds") != NULL ||
> +	       strstr(mnt_ops, "delegate_maps") != NULL ||
> +	       strstr(mnt_ops, "delegate_progs") != NULL ||
> +	       strstr(mnt_ops, "delegate_attachs") != NULL;
> +}
> +
> +static char *get_delegate_value(const char *opts, const char *key)
> +{
> +	char *token, *rest, *ret = NULL;
> +	char *opts_copy = strdup(opts);
> +
> +	if (!opts_copy)
> +		return NULL;
> +
> +	for (token = strtok_r(opts_copy, ",", &rest); token != NULL;
> +			token = strtok_r(NULL, ",", &rest)) {
> +		if (strncmp(token, key, strlen(key)) == 0 &&
> +				token[strlen(key)] == '=') {
> +			ret = token + strlen(key) + 1;
> +			break;
> +		}
> +	}
> +	free(opts_copy);
> +
> +	return ret;
> +}
> +
> +static void print_items_per_line(const char *input, int items_per_line)
> +{
> +	char *str, *rest;
> +	int cnt = 0;
> +	char *strs = strdup(input);
> +
> +	if (!strs)
> +		return;
> +
> +	for (str = strtok_r(strs, ":", &rest); str != NULL;
> +			str = strtok_r(NULL, ":", &rest)) {
> +		if (cnt % items_per_line == 0)
> +			printf("\n\t");
> +
> +		printf("%-20s", str);
> +		cnt++;
> +	}
> +
> +	free(strs);
> +}
> +
> +#define ITEMS_PER_LINE 4
> +static void show_token_info_plain(struct mntent *mntent)
> +{
> +	char *value;
> +
> +	printf("\ntoken_info:");
> +	printf("\n\t%s\n", mntent->mnt_dir);
> +
> +	printf("\nallowed_cmds:");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
> +	if (value)
> +		print_items_per_line(value, ITEMS_PER_LINE);
> +	printf("\n");
> +
> +	printf("\nallowed_maps:");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
> +	if (value)
> +		print_items_per_line(value, ITEMS_PER_LINE);
> +	printf("\n");
> +
> +	printf("\nallowed_progs:");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
> +	if (value)
> +		print_items_per_line(value, ITEMS_PER_LINE);
> +	printf("\n");
> +
> +	printf("\nallowed_attachs:");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
> +	if (value)
> +		print_items_per_line(value, ITEMS_PER_LINE);
> +	printf("\n");
> +}
> +
> +static void __json_array_str(const char *input)


Nit: Why the double underscore in the function name? Let's use a more
explicit name also, maybe something like "split_to_json_array"?


> +{
> +	char *str, *rest;
> +	char *strs = strdup(input);
> +
> +	if (!strs)
> +		return;
> +
> +	jsonw_start_array(json_wtr);
> +	for (str = strtok_r(strs, ":", &rest); str != NULL;
> +			str = strtok_r(NULL, ":", &rest)) {
> +		jsonw_string(json_wtr, str);
> +	}
> +	jsonw_end_array(json_wtr);
> +
> +	free(strs);
> +}
> +
> +static void show_token_info_json(struct mntent *mntent)
> +{
> +	char *value;
> +
> +	jsonw_start_object(json_wtr);
> +
> +	jsonw_string_field(json_wtr, "token_info", mntent->mnt_dir);
> +
> +	jsonw_name(json_wtr, "allowed_cmds");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
> +	if (value)
> +		__json_array_str(value);


As mentioned above, you need to change __json_array_str() to print
something when you don't get a "value" here - just have it print an
empty array.


> +
> +	jsonw_name(json_wtr, "allowed_maps");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
> +	if (value)
> +		__json_array_str(value);
> +
> +	jsonw_name(json_wtr, "allowed_progs");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
> +	if (value)
> +		__json_array_str(value);
> +
> +	jsonw_name(json_wtr, "allowed_attachs");
> +	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
> +	if (value)
> +		__json_array_str(value);
> +
> +	jsonw_end_object(json_wtr);
> +}
> +
> +static int __show_token_info(struct mntent *mntent)
> +{
> +
> +	if (json_output)
> +		show_token_info_json(mntent);
> +	else
> +		show_token_info_plain(mntent);
> +
> +	return 0;
> +}
> +
> +static int show_token_info(void)
> +{
> +	FILE *fp;
> +	struct mntent *ent;
> +	bool hit = false;
> +
> +	fp = setmntent(MOUNTS_FILE, "r");
> +	if (!fp) {
> +		p_err("Failed to open:%s", MOUNTS_FILE);


Missing space after the colon, in the error message.


> +		return -1;
> +	}
> +
> +	while ((ent = getmntent(fp)) != NULL) {
> +		if (strcmp(ent->mnt_type, "bpf") == 0) {


File common.c has:

		if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
			continue;

Maybe do the same for consistency, and to avoid indenting too far right?


> +			if (has_delegate_options(ent->mnt_opts)) {
> +				hit = true;
> +				break;


Apologies, my knowledge of BPF tokens is limited. Can you have only one
token exposed through a bpffs at a time? Asking because I know you can
have several bpffs on your system, if each can have delegate options
then why stop after the first bpffs mount point you find?


> +			}
> +		}
> +	}
> +
> +	if (hit)
> +		__show_token_info(ent);


Maybe at least a p_info() message if you don't find anything to print?


> +	endmntent(fp);
> +
> +	return 0;
> +}
> +
> +static int do_show(int argc, char **argv)
> +{
> +	if (argc)
> +		return BAD_ARG();
> +
> +	return show_token_info();
> +}
> +
> +static int do_help(int argc, char **argv)
> +{
> +	if (json_output) {
> +		jsonw_null(json_wtr);
> +		return 0;
> +	}
> +
> +	fprintf(stderr,
> +		"Usage: %1$s %2$s { show | list }\n"
> +		"	%1$s %2$s help\n"
> +		"\n"
> +		"",
> +		bin_name, argv[-2]);
> +	return 0;
> +}
> +
> +static const struct cmd cmds[] = {
> +	{ "show",	do_show },
> +	{ "help",	do_help },
> +	{ "list",	do_show },


Nit: Can we have "help" coming third, below both "show" and "list" please?


> +	{ 0 }
> +};
> +
> +int do_token(int argc, char **argv)
> +{
> +	return cmd_select(cmds, argc, argv, do_help);
> +}

Re: [PATCH bpf-next 1/2] bpftool: Add bpf_token show

[Tao Chen]

在 2025/7/22 00:23, Quentin Monnet 写道:
> Thanks a lot for this!
> 

Hi Quenin,

> 
> 2025-07-21 01:33 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
>> Add `bpftool token show` command to get token info
>> from bpf fs in /proc/mounts.
>>
>> Example plain output for `token show`:
>> token_info:
>>          /sys/fs/bpf/token
>>
>> allowed_cmds:
>>          map_create          prog_load
>>
>> allowed_maps:
>>
>> allowed_progs:
>>          kprobe
>>
>> allowed_attachs:
>>          xdp
>>
>> Example json output for `token show`:
>> {
>>      "token_info": "/sys/fs/bpf/token",
>>      "allowed_cmds": ["map_create","prog_load"
>>      ],
>>      "allowed_maps":
> 
> 
> This is not valid JSON. You're missing a value for "allowed_maps" (here
> it should likely be an empty array), and the comma:
> 
> 	"allowed_maps": [],
> 
> 
>>      "allowed_progs": ["kprobe"
>>      ],
>>      "allowed_attachs": ["xdp"
>>      ]
>> }
>>
>> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
>> ---
>>   tools/bpf/bpftool/main.c  |   3 +-
>>   tools/bpf/bpftool/main.h  |   1 +
>>   tools/bpf/bpftool/token.c | 229 ++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 232 insertions(+), 1 deletion(-)
>>   create mode 100644 tools/bpf/bpftool/token.c
>>
>> diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
>> index 2b7f2bd3a7d..0f1183b2ed0 100644
>> --- a/tools/bpf/bpftool/main.c
>> +++ b/tools/bpf/bpftool/main.c
>> @@ -61,7 +61,7 @@ static int do_help(int argc, char **argv)
>>   		"       %s batch file FILE\n"
>>   		"       %s version\n"
>>   		"\n"
>> -		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
>> +		"       OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter | token }\n"
>>   		"       " HELP_SPEC_OPTIONS " |\n"
>>   		"                    {-V|--version} }\n"
>>   		"",
>> @@ -87,6 +87,7 @@ static const struct cmd commands[] = {
>>   	{ "gen",	do_gen },
>>   	{ "struct_ops",	do_struct_ops },
>>   	{ "iter",	do_iter },
>> +	{ "token",	do_token },
>>   	{ "version",	do_version },
>>   	{ 0 }
>>   };
>> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
>> index 6db704fda5c..a2bb0714b3d 100644
>> --- a/tools/bpf/bpftool/main.h
>> +++ b/tools/bpf/bpftool/main.h
>> @@ -166,6 +166,7 @@ int do_tracelog(int argc, char **arg) __weak;
>>   int do_feature(int argc, char **argv) __weak;
>>   int do_struct_ops(int argc, char **argv) __weak;
>>   int do_iter(int argc, char **argv) __weak;
>> +int do_token(int argc, char **argv) __weak;
>>   
>>   int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
>>   int prog_parse_fd(int *argc, char ***argv);
>> diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
>> new file mode 100644
>> index 00000000000..2fcaff4f2ba
>> --- /dev/null
>> +++ b/tools/bpf/bpftool/token.c
>> @@ -0,0 +1,229 @@
>> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +
>> +#ifndef _GNU_SOURCE
>> +#define _GNU_SOURCE
>> +#endif
>> +#include <errno.h>
>> +#include <fcntl.h>
>> +#include <stdbool.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <unistd.h>
>> +#include <mntent.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +
>> +#include "json_writer.h"
>> +#include "main.h"
>> +
>> +#define MOUNTS_FILE "/proc/mounts"
>> +
>> +#define zclose(fd) do { if (fd >= 0) close(fd); fd = -1; } while (0)
> 
> 
> Seems unused?
> 
My fault, will remove it in v2, thanks.

> 
>> +
>> +static bool has_delegate_options(const char *mnt_ops)
>> +{
>> +	return strstr(mnt_ops, "delegate_cmds") != NULL ||
>> +	       strstr(mnt_ops, "delegate_maps") != NULL ||
>> +	       strstr(mnt_ops, "delegate_progs") != NULL ||
>> +	       strstr(mnt_ops, "delegate_attachs") != NULL;
>> +}
>> +
>> +static char *get_delegate_value(const char *opts, const char *key)
>> +{
>> +	char *token, *rest, *ret = NULL;
>> +	char *opts_copy = strdup(opts);
>> +
>> +	if (!opts_copy)
>> +		return NULL;
>> +
>> +	for (token = strtok_r(opts_copy, ",", &rest); token != NULL;
>> +			token = strtok_r(NULL, ",", &rest)) {
>> +		if (strncmp(token, key, strlen(key)) == 0 &&
>> +				token[strlen(key)] == '=') {
>> +			ret = token + strlen(key) + 1;
>> +			break;
>> +		}
>> +	}
>> +	free(opts_copy);
>> +
>> +	return ret;
>> +}
>> +
>> +static void print_items_per_line(const char *input, int items_per_line)
>> +{
>> +	char *str, *rest;
>> +	int cnt = 0;
>> +	char *strs = strdup(input);
>> +
>> +	if (!strs)
>> +		return;
>> +
>> +	for (str = strtok_r(strs, ":", &rest); str != NULL;
>> +			str = strtok_r(NULL, ":", &rest)) {
>> +		if (cnt % items_per_line == 0)
>> +			printf("\n\t");
>> +
>> +		printf("%-20s", str);
>> +		cnt++;
>> +	}
>> +
>> +	free(strs);
>> +}
>> +
>> +#define ITEMS_PER_LINE 4
>> +static void show_token_info_plain(struct mntent *mntent)
>> +{
>> +	char *value;
>> +
>> +	printf("\ntoken_info:");
>> +	printf("\n\t%s\n", mntent->mnt_dir);
>> +
>> +	printf("\nallowed_cmds:");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
>> +	if (value)
>> +		print_items_per_line(value, ITEMS_PER_LINE);
>> +	printf("\n");
>> +
>> +	printf("\nallowed_maps:");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
>> +	if (value)
>> +		print_items_per_line(value, ITEMS_PER_LINE);
>> +	printf("\n");
>> +
>> +	printf("\nallowed_progs:");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
>> +	if (value)
>> +		print_items_per_line(value, ITEMS_PER_LINE);
>> +	printf("\n");
>> +
>> +	printf("\nallowed_attachs:");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
>> +	if (value)
>> +		print_items_per_line(value, ITEMS_PER_LINE);
>> +	printf("\n");
>> +}
>> +
>> +static void __json_array_str(const char *input)
> 
> 
> Nit: Why the double underscore in the function name? Let's use a more
> explicit name also, maybe something like "split_to_json_array"?
> 

Well, it looks better, will change it in v2.

> >> +{
>> +	char *str, *rest;
>> +	char *strs = strdup(input);
>> +
>> +	if (!strs)
>> +		return;
>> +
>> +	jsonw_start_array(json_wtr);
>> +	for (str = strtok_r(strs, ":", &rest); str != NULL;
>> +			str = strtok_r(NULL, ":", &rest)) {
>> +		jsonw_string(json_wtr, str);
>> +	}
>> +	jsonw_end_array(json_wtr);
>> +
>> +	free(strs);
>> +}
>> +
>> +static void show_token_info_json(struct mntent *mntent)
>> +{
>> +	char *value;
>> +
>> +	jsonw_start_object(json_wtr);
>> +
>> +	jsonw_string_field(json_wtr, "token_info", mntent->mnt_dir);
>> +
>> +	jsonw_name(json_wtr, "allowed_cmds");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
>> +	if (value)
>> +		__json_array_str(value);
> 
> 
> As mentioned above, you need to change __json_array_str() to print
> something when you don't get a "value" here - just have it print an
> empty array.
> 

As you mentioned, the 'value' will be checked within the 
__json_array_str, and print empty array if it is NULL in v2.

> 
>> +
>> +	jsonw_name(json_wtr, "allowed_maps");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
>> +	if (value)
>> +		__json_array_str(value);
>> +
>> +	jsonw_name(json_wtr, "allowed_progs");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
>> +	if (value)
>> +		__json_array_str(value);
>> +
>> +	jsonw_name(json_wtr, "allowed_attachs");
>> +	value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
>> +	if (value)
>> +		__json_array_str(value);
>> +
>> +	jsonw_end_object(json_wtr);
>> +}
>> +
>> +static int __show_token_info(struct mntent *mntent)
>> +{
>> +
>> +	if (json_output)
>> +		show_token_info_json(mntent);
>> +	else
>> +		show_token_info_plain(mntent);
>> +
>> +	return 0;
>> +}
>> +
>> +static int show_token_info(void)
>> +{
>> +	FILE *fp;
>> +	struct mntent *ent;
>> +	bool hit = false;
>> +
>> +	fp = setmntent(MOUNTS_FILE, "r");
>> +	if (!fp) {
>> +		p_err("Failed to open:%s", MOUNTS_FILE);
> 
> 
> Missing space after the colon, in the error message.
> 

will fix it in v2.

> 
>> +		return -1;
>> +	}
>> +
>> +	while ((ent = getmntent(fp)) != NULL) {
>> +		if (strcmp(ent->mnt_type, "bpf") == 0) {
> 
> 
> File common.c has:
> 
> 		if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
> 			continue;
> 
> Maybe do the same for consistency, and to avoid indenting too far right?
> 

Yes, i will refrence that, thanks.

> 
>> +			if (has_delegate_options(ent->mnt_opts)) {
>> +				hit = true;
>> +				break;
> 
> 
> Apologies, my knowledge of BPF tokens is limited. Can you have only one
> token exposed through a bpffs at a time? Asking because I know you can
> have several bpffs on your system, if each can have delegate options
> then why stop after the first bpffs mount point you find?
> 

Yes it is, only the first bpffs with token info will be showed above.
Actually, it will not be limited how many bpffs ceated in kernel, it 
depends on the user scenarios. In most cases, only one will be created. 
But, maybe it's better to show all. I will change it in v2.

> 
>> +			}
>> +		}
>> +	}
>> +
>> +	if (hit)
>> +		__show_token_info(ent);
> 
> 
> Maybe at least a p_info() message if you don't find anything to print?
> 
Ok, will add it in v2.

> 
>> +	endmntent(fp);
>> +
>> +	return 0;
>> +}
>> +
>> +static int do_show(int argc, char **argv)
>> +{
>> +	if (argc)
>> +		return BAD_ARG();
>> +
>> +	return show_token_info();
>> +}
>> +
>> +static int do_help(int argc, char **argv)
>> +{
>> +	if (json_output) {
>> +		jsonw_null(json_wtr);
>> +		return 0;
>> +	}
>> +
>> +	fprintf(stderr,
>> +		"Usage: %1$s %2$s { show | list }\n"
>> +		"	%1$s %2$s help\n"
>> +		"\n"
>> +		"",
>> +		bin_name, argv[-2]);
>> +	return 0;
>> +}
>> +
>> +static const struct cmd cmds[] = {
>> +	{ "show",	do_show },
>> +	{ "help",	do_help },
>> +	{ "list",	do_show },
> 
> 
> Nit: Can we have "help" coming third, below both "show" and "list" please?
> 

will change it in v2.

> 
>> +	{ 0 }
>> +};
>> +
>> +int do_token(int argc, char **argv)
>> +{
>> +	return cmd_select(cmds, argc, argv, do_help);
>> +}
> 
-- 
Best Regards
Tao Chen

Re: [PATCH bpf-next 1/2] bpftool: Add bpf_token show

[Quentin Monnet]

2025-07-22 13:48 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
> 在 2025/7/22 00:23, Quentin Monnet 写道:
>> Thanks a lot for this!
>>
> 
> Hi Quenin,
> 
>>
>> 2025-07-21 01:33 UTC+0800 ~ Tao Chen <chen.dylane@linux.dev>
>>> Add `bpftool token show` command to get token info
>>> from bpf fs in /proc/mounts.
>>>
>>> Example plain output for `token show`:
>>> token_info:
>>>          /sys/fs/bpf/token
>>>
>>> allowed_cmds:
>>>          map_create          prog_load
>>>
>>> allowed_maps:
>>>
>>> allowed_progs:
>>>          kprobe
>>>
>>> allowed_attachs:
>>>          xdp
>>>
>>> Example json output for `token show`:
>>> {
>>>      "token_info": "/sys/fs/bpf/token",
>>>      "allowed_cmds": ["map_create","prog_load"
>>>      ],
>>>      "allowed_maps":
>>
>>
>> This is not valid JSON. You're missing a value for "allowed_maps" (here
>> it should likely be an empty array), and the comma:
>>
>>     "allowed_maps": [],
>>
>>
>>>      "allowed_progs": ["kprobe"
>>>      ],
>>>      "allowed_attachs": ["xdp"
>>>      ]
>>> }
>>>
>>> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
>>> ---
>>>   tools/bpf/bpftool/main.c  |   3 +-
>>>   tools/bpf/bpftool/main.h  |   1 +
>>>   tools/bpf/bpftool/token.c | 229 ++++++++++++++++++++++++++++++++++++++
>>>   3 files changed, 232 insertions(+), 1 deletion(-)
>>>   create mode 100644 tools/bpf/bpftool/token.c
>>>

[...]

>>> diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
>>> new file mode 100644
>>> index 00000000000..2fcaff4f2ba
>>> --- /dev/null
>>> +++ b/tools/bpf/bpftool/token.c

[...]

>>> +            if (has_delegate_options(ent->mnt_opts)) {
>>> +                hit = true;
>>> +                break;
>>
>>
>> Apologies, my knowledge of BPF tokens is limited. Can you have only one
>> token exposed through a bpffs at a time? Asking because I know you can
>> have several bpffs on your system, if each can have delegate options
>> then why stop after the first bpffs mount point you find?
>>
> 
> Yes it is, only the first bpffs with token info will be showed above.
> Actually, it will not be limited how many bpffs ceated in kernel, it
> depends on the user scenarios. In most cases, only one will be created.
> But, maybe it's better to show all. I will change it in v2.

Yes please. If there are several tokens available, bpftool should "list"
them all, as the command name implies. The user scenarios don't really
count here, we should just dump all token info we can see. In the
future, we could then add the possibility to take an argument (likely a
path to a bpffs) to show info for a particular mountpoint; a bit like
you can list all existing programs with "bpftool prog show" but can also
chose to pick one with "bpftool prog show id ...".

If we print info for several mountpoint, I'd suggest adjusting the
format for the plain output slightly: I'd remove the blank lines between
the different sections to get something more compact, maybe play with
the indent as well, like when we list programs or maps.

Thanks,
Quentin