* [PATCH bpf-next v3 0/4] bpftool: btf: Support dumping a single type from file
@ 2024-12-09 23:44 Daniel Xu
2024-12-09 23:44 ` [PATCH bpf-next v3 3/4] " Daniel Xu
0 siblings, 1 reply; 5+ messages in thread
From: Daniel Xu @ 2024-12-09 23:44 UTC (permalink / raw)
To: linux-kernel, bpf, netdev, qmo; +Cc: antony, toke, martin.lau
Some projects, for example xdp-tools [0], prefer to check in a minimized
vmlinux.h rather than the complete file which can get rather large.
However, when you try to add a minimized version of a complex struct (eg
struct xfrm_state), things can get quite complex if you're trying to
manually untangle and deduplicate the dependencies.
This commit teaches bpftool to do a minimized dump of a single type by
providing an optional root_id argument.
Example usage:
$ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
[12643] STRUCT 'xfrm_state' size=912 vlen=58
$ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
[..]
struct xfrm_type_offload;
struct xfrm_sec_ctx;
struct xfrm_state {
possible_net_t xs_net;
union {
struct hlist_node gclist;
struct hlist_node bydst;
};
union {
struct hlist_node dev_gclist;
struct hlist_node bysrc;
};
struct hlist_node byspi;
[..]
[0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
=== Changelog ===
Changes in v3:
* Make `root_id` a top level btf-dump argument rather than attached to `file`
* Update bash completion script
* Refactor root_type_ids checking to after btf handle creation
* Update help messages and fix existing man page inconsistency
Changes in v2:
* Add early error check for invalid BTF ID
Daniel Xu (4):
bpftool: man: Add missing format argument to command description
bpftool: btf: Validate root_type_ids early
bpftool: btf: Support dumping a single type from file
bpftool: bash: Add bash completion for root_id argument
.../bpf/bpftool/Documentation/bpftool-btf.rst | 7 ++--
tools/bpf/bpftool/bash-completion/bpftool | 7 ++--
tools/bpf/bpftool/btf.c | 33 ++++++++++++++++++-
3 files changed, 42 insertions(+), 5 deletions(-)
--
2.46.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH bpf-next v3 3/4] bpftool: btf: Support dumping a single type from file
2024-12-09 23:44 [PATCH bpf-next v3 0/4] bpftool: btf: Support dumping a single type from file Daniel Xu
@ 2024-12-09 23:44 ` Daniel Xu
2024-12-12 19:09 ` Andrii Nakryiko
0 siblings, 1 reply; 5+ messages in thread
From: Daniel Xu @ 2024-12-09 23:44 UTC (permalink / raw)
To: hawk, john.fastabend, ast, qmo, davem, daniel, andrii, kuba
Cc: martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo,
jolsa, bpf, linux-kernel, netdev, antony, toke
Some projects, for example xdp-tools [0], prefer to check in a minimized
vmlinux.h rather than the complete file which can get rather large.
However, when you try to add a minimized version of a complex struct (eg
struct xfrm_state), things can get quite complex if you're trying to
manually untangle and deduplicate the dependencies.
This commit teaches bpftool to do a minimized dump of a single type by
providing an optional root_id argument.
Example usage:
$ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
[12643] STRUCT 'xfrm_state' size=912 vlen=58
$ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
[..]
struct xfrm_type_offload;
struct xfrm_sec_ctx;
struct xfrm_state {
possible_net_t xs_net;
union {
struct hlist_node gclist;
struct hlist_node bydst;
};
union {
struct hlist_node dev_gclist;
struct hlist_node bysrc;
};
struct hlist_node byspi;
[..]
[0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
.../bpf/bpftool/Documentation/bpftool-btf.rst | 7 +++++--
tools/bpf/bpftool/btf.c | 21 ++++++++++++++++++-
2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
index 245569f43035..4899b2c10777 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
@@ -24,7 +24,7 @@ BTF COMMANDS
=============
| **bpftool** **btf** { **show** | **list** } [**id** *BTF_ID*]
-| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*]
+| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*] [**root_id** *ROOT_ID*]
| **bpftool** **btf help**
|
| *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
@@ -43,7 +43,7 @@ bpftool btf { show | list } [id *BTF_ID*]
that hold open file descriptors (FDs) against BTF objects. On such kernels
bpftool will automatically emit this information as well.
-bpftool btf dump *BTF_SRC* [format *FORMAT*]
+bpftool btf dump *BTF_SRC* [format *FORMAT*] [root_id *ROOT_ID*]
Dump BTF entries from a given *BTF_SRC*.
When **id** is specified, BTF object with that ID will be loaded and all
@@ -67,6 +67,9 @@ bpftool btf dump *BTF_SRC* [format *FORMAT*]
formatting, the output is sorted by default. Use the **unsorted** option
to avoid sorting the output.
+ **root_id** option can be used to filter a dump to a single type and all
+ its dependent types. It cannot be used with any other types of filtering.
+
bpftool btf help
Print short help message.
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 3e995faf9efa..18b037a1414b 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -993,6 +993,25 @@ static int do_dump(int argc, char **argv)
goto done;
}
NEXT_ARG();
+ } else if (is_prefix(*argv, "root_id")) {
+ __u32 root_id;
+ char *end;
+
+ if (root_type_cnt) {
+ p_err("cannot use root_id with other type filtering");
+ err = -EINVAL;
+ goto done;
+ }
+
+ NEXT_ARG();
+ root_id = strtoul(*argv, &end, 0);
+ if (*end) {
+ err = -1;
+ p_err("can't parse %s as root ID", *argv);
+ goto done;
+ }
+ root_type_ids[root_type_cnt++] = root_id;
+ NEXT_ARG();
} else if (is_prefix(*argv, "unsorted")) {
sort_dump_c = false;
NEXT_ARG();
@@ -1403,7 +1422,7 @@ static int do_help(int argc, char **argv)
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
- " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
+ " %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n"
" %1$s %2$s help\n"
"\n"
" BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
--
2.46.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v3 3/4] bpftool: btf: Support dumping a single type from file
2024-12-09 23:44 ` [PATCH bpf-next v3 3/4] " Daniel Xu
@ 2024-12-12 19:09 ` Andrii Nakryiko
2024-12-12 23:41 ` Daniel Xu
0 siblings, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2024-12-12 19:09 UTC (permalink / raw)
To: Daniel Xu
Cc: hawk, john.fastabend, ast, qmo, davem, daniel, andrii, kuba,
martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo,
jolsa, bpf, linux-kernel, netdev, antony, toke
On Mon, Dec 9, 2024 at 3:45 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
>
> Some projects, for example xdp-tools [0], prefer to check in a minimized
> vmlinux.h rather than the complete file which can get rather large.
>
> However, when you try to add a minimized version of a complex struct (eg
> struct xfrm_state), things can get quite complex if you're trying to
> manually untangle and deduplicate the dependencies.
>
> This commit teaches bpftool to do a minimized dump of a single type by
> providing an optional root_id argument.
>
> Example usage:
>
> $ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
> [12643] STRUCT 'xfrm_state' size=912 vlen=58
>
> $ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
> #ifndef __VMLINUX_H__
> #define __VMLINUX_H__
>
> [..]
>
> struct xfrm_type_offload;
>
> struct xfrm_sec_ctx;
>
> struct xfrm_state {
> possible_net_t xs_net;
> union {
> struct hlist_node gclist;
> struct hlist_node bydst;
> };
> union {
> struct hlist_node dev_gclist;
> struct hlist_node bysrc;
> };
> struct hlist_node byspi;
> [..]
>
> [0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
>
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> ---
> .../bpf/bpftool/Documentation/bpftool-btf.rst | 7 +++++--
> tools/bpf/bpftool/btf.c | 21 ++++++++++++++++++-
> 2 files changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> index 245569f43035..4899b2c10777 100644
> --- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> +++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> @@ -24,7 +24,7 @@ BTF COMMANDS
> =============
>
> | **bpftool** **btf** { **show** | **list** } [**id** *BTF_ID*]
> -| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*]
> +| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*] [**root_id** *ROOT_ID*]
> | **bpftool** **btf help**
> |
> | *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
> @@ -43,7 +43,7 @@ bpftool btf { show | list } [id *BTF_ID*]
> that hold open file descriptors (FDs) against BTF objects. On such kernels
> bpftool will automatically emit this information as well.
>
> -bpftool btf dump *BTF_SRC* [format *FORMAT*]
> +bpftool btf dump *BTF_SRC* [format *FORMAT*] [root_id *ROOT_ID*]
> Dump BTF entries from a given *BTF_SRC*.
>
> When **id** is specified, BTF object with that ID will be loaded and all
> @@ -67,6 +67,9 @@ bpftool btf dump *BTF_SRC* [format *FORMAT*]
> formatting, the output is sorted by default. Use the **unsorted** option
> to avoid sorting the output.
>
> + **root_id** option can be used to filter a dump to a single type and all
> + its dependent types. It cannot be used with any other types of filtering.
> +
> bpftool btf help
> Print short help message.
>
> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> index 3e995faf9efa..18b037a1414b 100644
> --- a/tools/bpf/bpftool/btf.c
> +++ b/tools/bpf/bpftool/btf.c
> @@ -993,6 +993,25 @@ static int do_dump(int argc, char **argv)
> goto done;
> }
> NEXT_ARG();
> + } else if (is_prefix(*argv, "root_id")) {
> + __u32 root_id;
> + char *end;
> +
> + if (root_type_cnt) {
> + p_err("cannot use root_id with other type filtering");
this is a confusing error if the user just wanted to provide two
root_id arguments... Also, why don't we allow multiple root_ids?
I'd bump root_type_ids[] to have something like 16 elements or
something (though we can always do dynamic realloc as well, probably),
and allow multiple types to be specified.
Thoughts?
> + err = -EINVAL;
> + goto done;
> + }
> +
> + NEXT_ARG();
> + root_id = strtoul(*argv, &end, 0);
> + if (*end) {
> + err = -1;
> + p_err("can't parse %s as root ID", *argv);
> + goto done;
> + }
> + root_type_ids[root_type_cnt++] = root_id;
> + NEXT_ARG();
> } else if (is_prefix(*argv, "unsorted")) {
> sort_dump_c = false;
> NEXT_ARG();
> @@ -1403,7 +1422,7 @@ static int do_help(int argc, char **argv)
>
> fprintf(stderr,
> "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
> - " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
> + " %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n"
> " %1$s %2$s help\n"
> "\n"
> " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
> --
> 2.46.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v3 3/4] bpftool: btf: Support dumping a single type from file
2024-12-12 19:09 ` Andrii Nakryiko
@ 2024-12-12 23:41 ` Daniel Xu
2024-12-13 0:12 ` Andrii Nakryiko
0 siblings, 1 reply; 5+ messages in thread
From: Daniel Xu @ 2024-12-12 23:41 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: hawk, john.fastabend, ast, qmo, davem, daniel, andrii, kuba,
martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo,
jolsa, bpf, linux-kernel, netdev, antony, toke
On Thu, Dec 12, 2024 at 11:09:34AM GMT, Andrii Nakryiko wrote:
> On Mon, Dec 9, 2024 at 3:45 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
> >
> > Some projects, for example xdp-tools [0], prefer to check in a minimized
> > vmlinux.h rather than the complete file which can get rather large.
> >
> > However, when you try to add a minimized version of a complex struct (eg
> > struct xfrm_state), things can get quite complex if you're trying to
> > manually untangle and deduplicate the dependencies.
> >
> > This commit teaches bpftool to do a minimized dump of a single type by
> > providing an optional root_id argument.
> >
> > Example usage:
> >
> > $ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
> > [12643] STRUCT 'xfrm_state' size=912 vlen=58
> >
> > $ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
> > #ifndef __VMLINUX_H__
> > #define __VMLINUX_H__
> >
> > [..]
> >
> > struct xfrm_type_offload;
> >
> > struct xfrm_sec_ctx;
> >
> > struct xfrm_state {
> > possible_net_t xs_net;
> > union {
> > struct hlist_node gclist;
> > struct hlist_node bydst;
> > };
> > union {
> > struct hlist_node dev_gclist;
> > struct hlist_node bysrc;
> > };
> > struct hlist_node byspi;
> > [..]
> >
> > [0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
> >
> > Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> > ---
> > .../bpf/bpftool/Documentation/bpftool-btf.rst | 7 +++++--
> > tools/bpf/bpftool/btf.c | 21 ++++++++++++++++++-
> > 2 files changed, 25 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > index 245569f43035..4899b2c10777 100644
> > --- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > +++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > @@ -24,7 +24,7 @@ BTF COMMANDS
> > =============
> >
> > | **bpftool** **btf** { **show** | **list** } [**id** *BTF_ID*]
> > -| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*]
> > +| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*] [**root_id** *ROOT_ID*]
> > | **bpftool** **btf help**
> > |
> > | *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
> > @@ -43,7 +43,7 @@ bpftool btf { show | list } [id *BTF_ID*]
> > that hold open file descriptors (FDs) against BTF objects. On such kernels
> > bpftool will automatically emit this information as well.
> >
> > -bpftool btf dump *BTF_SRC* [format *FORMAT*]
> > +bpftool btf dump *BTF_SRC* [format *FORMAT*] [root_id *ROOT_ID*]
> > Dump BTF entries from a given *BTF_SRC*.
> >
> > When **id** is specified, BTF object with that ID will be loaded and all
> > @@ -67,6 +67,9 @@ bpftool btf dump *BTF_SRC* [format *FORMAT*]
> > formatting, the output is sorted by default. Use the **unsorted** option
> > to avoid sorting the output.
> >
> > + **root_id** option can be used to filter a dump to a single type and all
> > + its dependent types. It cannot be used with any other types of filtering.
> > +
> > bpftool btf help
> > Print short help message.
> >
> > diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> > index 3e995faf9efa..18b037a1414b 100644
> > --- a/tools/bpf/bpftool/btf.c
> > +++ b/tools/bpf/bpftool/btf.c
> > @@ -993,6 +993,25 @@ static int do_dump(int argc, char **argv)
> > goto done;
> > }
> > NEXT_ARG();
> > + } else if (is_prefix(*argv, "root_id")) {
> > + __u32 root_id;
> > + char *end;
> > +
> > + if (root_type_cnt) {
> > + p_err("cannot use root_id with other type filtering");
>
> this is a confusing error if the user just wanted to provide two
> root_id arguments... Also, why don't we allow multiple root_ids?
>
> I'd bump root_type_ids[] to have something like 16 elements or
> something (though we can always do dynamic realloc as well, probably),
> and allow multiple types to be specified.
>
> Thoughts?
That's a good point. I added this check b/c I didn't think it would
make sense to allow `root_id` filtering in combination with map dump
filtering (which uses same root_type_ids param):
map MAP [{key | value | kv | all}]
But code can easily be tweaked to still block combination but allow
multiple `root_id`s when used alone. 16 seems sufficient to me.
Do you think it'd be more bpftool-y to require "root_id" each time or to
just take a comma separated value?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v3 3/4] bpftool: btf: Support dumping a single type from file
2024-12-12 23:41 ` Daniel Xu
@ 2024-12-13 0:12 ` Andrii Nakryiko
0 siblings, 0 replies; 5+ messages in thread
From: Andrii Nakryiko @ 2024-12-13 0:12 UTC (permalink / raw)
To: Daniel Xu
Cc: hawk, john.fastabend, ast, qmo, davem, daniel, andrii, kuba,
martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo,
jolsa, bpf, linux-kernel, netdev, antony, toke
On Thu, Dec 12, 2024 at 3:41 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
>
> On Thu, Dec 12, 2024 at 11:09:34AM GMT, Andrii Nakryiko wrote:
> > On Mon, Dec 9, 2024 at 3:45 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
> > >
> > > Some projects, for example xdp-tools [0], prefer to check in a minimized
> > > vmlinux.h rather than the complete file which can get rather large.
> > >
> > > However, when you try to add a minimized version of a complex struct (eg
> > > struct xfrm_state), things can get quite complex if you're trying to
> > > manually untangle and deduplicate the dependencies.
> > >
> > > This commit teaches bpftool to do a minimized dump of a single type by
> > > providing an optional root_id argument.
> > >
> > > Example usage:
> > >
> > > $ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
> > > [12643] STRUCT 'xfrm_state' size=912 vlen=58
> > >
> > > $ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
> > > #ifndef __VMLINUX_H__
> > > #define __VMLINUX_H__
> > >
> > > [..]
> > >
> > > struct xfrm_type_offload;
> > >
> > > struct xfrm_sec_ctx;
> > >
> > > struct xfrm_state {
> > > possible_net_t xs_net;
> > > union {
> > > struct hlist_node gclist;
> > > struct hlist_node bydst;
> > > };
> > > union {
> > > struct hlist_node dev_gclist;
> > > struct hlist_node bysrc;
> > > };
> > > struct hlist_node byspi;
> > > [..]
> > >
> > > [0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
> > >
> > > Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> > > ---
> > > .../bpf/bpftool/Documentation/bpftool-btf.rst | 7 +++++--
> > > tools/bpf/bpftool/btf.c | 21 ++++++++++++++++++-
> > > 2 files changed, 25 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > > index 245569f43035..4899b2c10777 100644
> > > --- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > > +++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
> > > @@ -24,7 +24,7 @@ BTF COMMANDS
> > > =============
> > >
> > > | **bpftool** **btf** { **show** | **list** } [**id** *BTF_ID*]
> > > -| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*]
> > > +| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*] [**root_id** *ROOT_ID*]
> > > | **bpftool** **btf help**
> > > |
> > > | *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
> > > @@ -43,7 +43,7 @@ bpftool btf { show | list } [id *BTF_ID*]
> > > that hold open file descriptors (FDs) against BTF objects. On such kernels
> > > bpftool will automatically emit this information as well.
> > >
> > > -bpftool btf dump *BTF_SRC* [format *FORMAT*]
> > > +bpftool btf dump *BTF_SRC* [format *FORMAT*] [root_id *ROOT_ID*]
> > > Dump BTF entries from a given *BTF_SRC*.
> > >
> > > When **id** is specified, BTF object with that ID will be loaded and all
> > > @@ -67,6 +67,9 @@ bpftool btf dump *BTF_SRC* [format *FORMAT*]
> > > formatting, the output is sorted by default. Use the **unsorted** option
> > > to avoid sorting the output.
> > >
> > > + **root_id** option can be used to filter a dump to a single type and all
> > > + its dependent types. It cannot be used with any other types of filtering.
> > > +
> > > bpftool btf help
> > > Print short help message.
> > >
> > > diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> > > index 3e995faf9efa..18b037a1414b 100644
> > > --- a/tools/bpf/bpftool/btf.c
> > > +++ b/tools/bpf/bpftool/btf.c
> > > @@ -993,6 +993,25 @@ static int do_dump(int argc, char **argv)
> > > goto done;
> > > }
> > > NEXT_ARG();
> > > + } else if (is_prefix(*argv, "root_id")) {
> > > + __u32 root_id;
> > > + char *end;
> > > +
> > > + if (root_type_cnt) {
> > > + p_err("cannot use root_id with other type filtering");
> >
> > this is a confusing error if the user just wanted to provide two
> > root_id arguments... Also, why don't we allow multiple root_ids?
> >
> > I'd bump root_type_ids[] to have something like 16 elements or
> > something (though we can always do dynamic realloc as well, probably),
> > and allow multiple types to be specified.
> >
> > Thoughts?
>
> That's a good point. I added this check b/c I didn't think it would
> make sense to allow `root_id` filtering in combination with map dump
> filtering (which uses same root_type_ids param):
>
> map MAP [{key | value | kv | all}]
>
> But code can easily be tweaked to still block combination but allow
> multiple `root_id`s when used alone. 16 seems sufficient to me.
>
> Do you think it'd be more bpftool-y to require "root_id" each time or to
> just take a comma separated value?
root_id 123 root_id 345 root_id 789
definitely more bpftool-y
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-12-13 0:12 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-12-09 23:44 [PATCH bpf-next v3 0/4] bpftool: btf: Support dumping a single type from file Daniel Xu
2024-12-09 23:44 ` [PATCH bpf-next v3 3/4] " Daniel Xu
2024-12-12 19:09 ` Andrii Nakryiko
2024-12-12 23:41 ` Daniel Xu
2024-12-13 0:12 ` Andrii Nakryiko
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).