Hi.
First, I hope you are fine and the same for your relatives.
In this patch, I added the command used to generate a BTF dump at the top of the
dump when outputting to C:
/*
* File generated by bpftool using:
* bpftool btf dump file /sys/kernel/btf/vmlinux format c
* DO NOT EDIT.
*/
The goal of this is to first warn users this file must not be edited and also
to document the command used to get it.
The idea was gathered from a message posted on iovisor/bcc repository and from
message written by bpf2go when it generates a file [1, 2].
This patch is clearly not a big change which impacts the future of bpftool but
I think it could be welcomed.
If you see any way to improve it or have any question, feel free to ask.
Francis Laniel (1):
bpftool: Add generating command to dumped file.
tools/bpf/bpftool/btf.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
Best regards and thank you in advance.
---
[1] https://github.com/iovisor/bcc/pull/4088#pullrequestreview-1032543916
[2] https://github.com/cilium/ebpf/blob/951bb28908d23e50fca063a2d51098ca028352bf/cmd/bpf2go/output.go#L21
--
2.25.1
This commit adds the following lines to file generated by dump:
/*
* File generated by bpftool using:
* bpftool btf dump file /sys/kernel/btf/vmlinux format c
* DO NOT EDIT.
*/
This warns users to not edit the file and documents the command used to
generate the file.
Signed-off-by: Francis Laniel <[email protected]>
---
tools/bpf/bpftool/btf.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 7e6accb9d9f7..eecfc27370c3 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -415,7 +415,8 @@ static void __printf(2, 0) btf_dump_printf(void *ctx,
}
static int dump_btf_c(const struct btf *btf,
- __u32 *root_type_ids, int root_type_cnt)
+ __u32 *root_type_ids, int root_type_cnt,
+ int argc, char **argv)
{
struct btf_dump *d;
int err = 0, i;
@@ -425,6 +426,14 @@ static int dump_btf_c(const struct btf *btf,
if (err)
return err;
+ printf("/*\n");
+ printf(" * File generated by bpftool using:\n");
+ printf(" * bpftool btf dump");
+ for (i = 0; i < argc; i++)
+ printf(" %s", argv[i]);
+ printf("\n");
+ printf(" * DO NOT EDIT.\n");
+ printf(" */\n");
printf("#ifndef __VMLINUX_H__\n");
printf("#define __VMLINUX_H__\n");
printf("\n");
@@ -507,8 +516,10 @@ static bool btf_is_kernel_module(__u32 btf_id)
static int do_dump(int argc, char **argv)
{
struct btf *btf = NULL, *base = NULL;
+ char **orig_argv = argv;
__u32 root_type_ids[2];
int root_type_cnt = 0;
+ int orig_argc = argc;
bool dump_c = false;
__u32 btf_id = -1;
const char *src;
@@ -649,7 +660,8 @@ static int do_dump(int argc, char **argv)
err = -ENOTSUP;
goto done;
}
- err = dump_btf_c(btf, root_type_ids, root_type_cnt);
+ err = dump_btf_c(btf, root_type_ids, root_type_cnt,
+ orig_argc, orig_argv);
} else {
err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
}
--
2.25.1
On 07/12, Francis Laniel wrote:
> This commit adds the following lines to file generated by dump:
> /*
> * File generated by bpftool using:
> * bpftool btf dump file /sys/kernel/btf/vmlinux format c
> * DO NOT EDIT.
> */
> This warns users to not edit the file and documents the command used to
> generate the file.
> Signed-off-by: Francis Laniel <[email protected]>
> ---
> tools/bpf/bpftool/btf.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> index 7e6accb9d9f7..eecfc27370c3 100644
> --- a/tools/bpf/bpftool/btf.c
> +++ b/tools/bpf/bpftool/btf.c
> @@ -415,7 +415,8 @@ static void __printf(2, 0) btf_dump_printf(void *ctx,
> }
> static int dump_btf_c(const struct btf *btf,
> - __u32 *root_type_ids, int root_type_cnt)
> + __u32 *root_type_ids, int root_type_cnt,
> + int argc, char **argv)
> {
> struct btf_dump *d;
> int err = 0, i;
> @@ -425,6 +426,14 @@ static int dump_btf_c(const struct btf *btf,
> if (err)
> return err;
> + printf("/*\n");
> + printf(" * File generated by bpftool using:\n");
> + printf(" * bpftool btf dump");
[..]
> + for (i = 0; i < argc; i++)
> + printf(" %s", argv[i]);
Do we really need that complexity to preserve the arguments?
For skeletons we're simply doing:
/* THIS FILE IS AUTOGENERATED BY BPFTOOL! */
So probably the same should be fine here?
Also, while at it, might be worth adding SPDX license comment? So let's
align with whatever we have in gen.c ?
> + printf("\n");
> + printf(" * DO NOT EDIT.\n");
> + printf(" */\n");
> printf("#ifndef __VMLINUX_H__\n");
> printf("#define __VMLINUX_H__\n");
> printf("\n");
> @@ -507,8 +516,10 @@ static bool btf_is_kernel_module(__u32 btf_id)
> static int do_dump(int argc, char **argv)
> {
> struct btf *btf = NULL, *base = NULL;
> + char **orig_argv = argv;
> __u32 root_type_ids[2];
> int root_type_cnt = 0;
> + int orig_argc = argc;
> bool dump_c = false;
> __u32 btf_id = -1;
> const char *src;
> @@ -649,7 +660,8 @@ static int do_dump(int argc, char **argv)
> err = -ENOTSUP;
> goto done;
> }
> - err = dump_btf_c(btf, root_type_ids, root_type_cnt);
> + err = dump_btf_c(btf, root_type_ids, root_type_cnt,
> + orig_argc, orig_argv);
> } else {
> err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
> }
> --
> 2.25.1
Hi.
Le mardi 12 juillet 2022, 22:47:40 CEST [email protected] a ?crit :
> On 07/12, Francis Laniel wrote:
> > This commit adds the following lines to file generated by dump:
> > /*
> >
> > * File generated by bpftool using:
> > * bpftool btf dump file /sys/kernel/btf/vmlinux format c
> > * DO NOT EDIT.
> > */
> >
> > This warns users to not edit the file and documents the command used to
> > generate the file.
> >
> > Signed-off-by: Francis Laniel <[email protected]>
> > ---
> >
> > tools/bpf/bpftool/btf.c | 16 ++++++++++++++--
> > 1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> > index 7e6accb9d9f7..eecfc27370c3 100644
> > --- a/tools/bpf/bpftool/btf.c
> > +++ b/tools/bpf/bpftool/btf.c
> > @@ -415,7 +415,8 @@ static void __printf(2, 0) btf_dump_printf(void *ctx,
> >
> > }
> >
> > static int dump_btf_c(const struct btf *btf,
> >
> > - __u32 *root_type_ids, int root_type_cnt)
> > + __u32 *root_type_ids, int root_type_cnt,
> > + int argc, char **argv)
> >
> > {
> >
> > struct btf_dump *d;
> > int err = 0, i;
> >
> > @@ -425,6 +426,14 @@ static int dump_btf_c(const struct btf *btf,
> >
> > if (err)
> >
> > return err;
> >
> > + printf("/*\n");
> > + printf(" * File generated by bpftool using:\n");
> > + printf(" * bpftool btf dump");
>
> [..]
>
> > + for (i = 0; i < argc; i++)
> > + printf(" %s", argv[i]);
>
> Do we really need that complexity to preserve the arguments?
I was also a bit sceptickal when I first wrote as I found this code a bit
complex for not so much added value.
But in my case, I do not use bpftool often, so having the command documented
in the generated file would have been useful.
I will just find another way to document (or I think now I will not forget it
anymore since this series).
> For skeletons we're simply doing:
>
> /* THIS FILE IS AUTOGENERATED BY BPFTOOL! */
>
> So probably the same should be fine here?
>
> Also, while at it, might be worth adding SPDX license comment? So let's
> align with whatever we have in gen.c ?
I will send a v2 aligned on skeletons in no more than 15 minutes.
> > + printf("\n");
> > + printf(" * DO NOT EDIT.\n");
> > + printf(" */\n");
> >
> > printf("#ifndef __VMLINUX_H__\n");
> > printf("#define __VMLINUX_H__\n");
> > printf("\n");
> >
> > @@ -507,8 +516,10 @@ static bool btf_is_kernel_module(__u32 btf_id)
> >
> > static int do_dump(int argc, char **argv)
> > {
> >
> > struct btf *btf = NULL, *base = NULL;
> >
> > + char **orig_argv = argv;
> >
> > __u32 root_type_ids[2];
> > int root_type_cnt = 0;
> >
> > + int orig_argc = argc;
> >
> > bool dump_c = false;
> > __u32 btf_id = -1;
> > const char *src;
> >
> > @@ -649,7 +660,8 @@ static int do_dump(int argc, char **argv)
> >
> > err = -ENOTSUP;
> > goto done;
> >
> > }
> >
> > - err = dump_btf_c(btf, root_type_ids, root_type_cnt);
> > + err = dump_btf_c(btf, root_type_ids, root_type_cnt,
> > + orig_argc, orig_argv);
> >
> > } else {
> >
> > err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
> >
> > }
> >
> > --
> > 2.25.1
Best regards.