* [PATCH] bpftool: Allow to read btf as raw data
@ 2019-10-24 13:30 Jiri Olsa
2019-10-24 17:55 ` Jakub Kicinski
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Jiri Olsa @ 2019-10-24 13:30 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: netdev, bpf, Andrii Nakryiko, Yonghong Song, Martin KaFai Lau,
Jakub Kicinski
The bpftool interface stays the same, but now it's possible
to run it over BTF raw data, like:
$ bpftool btf dump file /sys/kernel/btf/vmlinux
[1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
[3] CONST '(anon)' type_id=2
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
v3 changes:
- fix title
v2 changes:
- added is_btf_raw to find out which btf__parse_* function to call
- changed labels and error propagation in btf__parse_raw
- drop the err initialization, which is not needed under this change
tools/bpf/bpftool/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 56 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 9a9376d1d3df..a7b8bf233cf5 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -12,6 +12,9 @@
#include <libbpf.h>
#include <linux/btf.h>
#include <linux/hashtable.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
#include "btf.h"
#include "json_writer.h"
@@ -388,6 +391,54 @@ static int dump_btf_c(const struct btf *btf,
return err;
}
+static struct btf *btf__parse_raw(const char *file)
+{
+ struct btf *btf;
+ struct stat st;
+ __u8 *buf;
+ FILE *f;
+
+ if (stat(file, &st))
+ return NULL;
+
+ f = fopen(file, "rb");
+ if (!f)
+ return NULL;
+
+ buf = malloc(st.st_size);
+ if (!buf) {
+ btf = ERR_PTR(-ENOMEM);
+ goto exit_close;
+ }
+
+ if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) {
+ btf = ERR_PTR(-EINVAL);
+ goto exit_free;
+ }
+
+ btf = btf__new(buf, st.st_size);
+
+exit_free:
+ free(buf);
+exit_close:
+ fclose(f);
+ return btf;
+}
+
+static bool is_btf_raw(const char *file)
+{
+ __u16 magic = 0;
+ int fd;
+
+ fd = open(file, O_RDONLY);
+ if (fd < 0)
+ return false;
+
+ read(fd, &magic, sizeof(magic));
+ close(fd);
+ return magic == BTF_MAGIC;
+}
+
static int do_dump(int argc, char **argv)
{
struct btf *btf = NULL;
@@ -465,7 +516,11 @@ static int do_dump(int argc, char **argv)
}
NEXT_ARG();
} else if (is_prefix(src, "file")) {
- btf = btf__parse_elf(*argv, NULL);
+ if (is_btf_raw(*argv))
+ btf = btf__parse_raw(*argv);
+ else
+ btf = btf__parse_elf(*argv, NULL);
+
if (IS_ERR(btf)) {
err = PTR_ERR(btf);
btf = NULL;
--
2.21.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-24 13:30 [PATCH] bpftool: Allow to read btf as raw data Jiri Olsa
@ 2019-10-24 17:55 ` Jakub Kicinski
2019-10-25 7:15 ` Jiri Olsa
2019-10-25 5:10 ` Andrii Nakryiko
` (2 subsequent siblings)
3 siblings, 1 reply; 8+ messages in thread
From: Jakub Kicinski @ 2019-10-24 17:55 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, Daniel Borkmann, netdev, bpf,
Andrii Nakryiko, Yonghong Song, Martin KaFai Lau
On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote:
> The bpftool interface stays the same, but now it's possible
> to run it over BTF raw data, like:
>
> $ bpftool btf dump file /sys/kernel/btf/vmlinux
> [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [3] CONST '(anon)' type_id=2
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> v3 changes:
> - fix title
>
> v2 changes:
> - added is_btf_raw to find out which btf__parse_* function to call
> - changed labels and error propagation in btf__parse_raw
> - drop the err initialization, which is not needed under this change
Aw, this is v3? Looks like I replied to the older now, such confusion :)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-24 17:55 ` Jakub Kicinski
@ 2019-10-25 7:15 ` Jiri Olsa
0 siblings, 0 replies; 8+ messages in thread
From: Jiri Olsa @ 2019-10-25 7:15 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Jiri Olsa, Alexei Starovoitov, Daniel Borkmann, netdev, bpf,
Andrii Nakryiko, Yonghong Song, Martin KaFai Lau
On Thu, Oct 24, 2019 at 10:55:37AM -0700, Jakub Kicinski wrote:
> On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote:
> > The bpftool interface stays the same, but now it's possible
> > to run it over BTF raw data, like:
> >
> > $ bpftool btf dump file /sys/kernel/btf/vmlinux
> > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> > [3] CONST '(anon)' type_id=2
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > v3 changes:
> > - fix title
> >
> > v2 changes:
> > - added is_btf_raw to find out which btf__parse_* function to call
> > - changed labels and error propagation in btf__parse_raw
> > - drop the err initialization, which is not needed under this change
>
>
> Aw, this is v3? Looks like I replied to the older now, such confusion :)
yea, that went well.. sry, missed the v3 in title
jirka
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-24 13:30 [PATCH] bpftool: Allow to read btf as raw data Jiri Olsa
2019-10-24 17:55 ` Jakub Kicinski
@ 2019-10-25 5:10 ` Andrii Nakryiko
2019-10-25 18:39 ` Jakub Kicinski
2019-10-25 21:40 ` Daniel Borkmann
3 siblings, 0 replies; 8+ messages in thread
From: Andrii Nakryiko @ 2019-10-25 5:10 UTC (permalink / raw)
To: Jiri Olsa, Alexei Starovoitov, Daniel Borkmann
Cc: netdev, bpf, Yonghong Song, Martin Lau, Jakub Kicinski, andrii.nakryiko
On 10/24/19 6:30 AM, Jiri Olsa wrote:
> The bpftool interface stays the same, but now it's possible
> to run it over BTF raw data, like:
>
> $ bpftool btf dump file /sys/kernel/btf/vmlinux
> [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [3] CONST '(anon)' type_id=2
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> v3 changes:
> - fix title
The subject (by now) should be "[PATCH v3 bpf-next] ...". Include both
version and intended tree (bpf-next usually).
>
> v2 changes:
> - added is_btf_raw to find out which btf__parse_* function to call
> - changed labels and error propagation in btf__parse_raw
> - drop the err initialization, which is not needed under this change
>
> tools/bpf/bpftool/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 56 insertions(+), 1 deletion(-)
>
Overall looks good. It's kind of sad that we re-open that file twice,
but we can optimize that later, if it ever is a problem. We should
probably eventually implement btf__parse_raw as libbpf API with mmap2().
But perfect is the enemy of the good, so:
Acked-by: Andrii Nakryiko <andriin@fb.com>
> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> index 9a9376d1d3df..a7b8bf233cf5 100644
> --- a/tools/bpf/bpftool/btf.c
> +++ b/tools/bpf/bpftool/btf.c
> @@ -12,6 +12,9 @@
[...]
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-24 13:30 [PATCH] bpftool: Allow to read btf as raw data Jiri Olsa
2019-10-24 17:55 ` Jakub Kicinski
2019-10-25 5:10 ` Andrii Nakryiko
@ 2019-10-25 18:39 ` Jakub Kicinski
2019-10-25 20:03 ` Jiri Olsa
2019-10-25 21:40 ` Daniel Borkmann
3 siblings, 1 reply; 8+ messages in thread
From: Jakub Kicinski @ 2019-10-25 18:39 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, Daniel Borkmann, netdev, bpf,
Andrii Nakryiko, Yonghong Song, Martin KaFai Lau
On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote:
> The bpftool interface stays the same, but now it's possible
> to run it over BTF raw data, like:
>
> $ bpftool btf dump file /sys/kernel/btf/vmlinux
> [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [3] CONST '(anon)' type_id=2
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-25 18:39 ` Jakub Kicinski
@ 2019-10-25 20:03 ` Jiri Olsa
2019-10-26 18:42 ` Jakub Kicinski
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Olsa @ 2019-10-25 20:03 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Jiri Olsa, Alexei Starovoitov, Daniel Borkmann, netdev, bpf,
Andrii Nakryiko, Yonghong Song, Martin KaFai Lau
On Fri, Oct 25, 2019 at 11:39:01AM -0700, Jakub Kicinski wrote:
> On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote:
> > The bpftool interface stays the same, but now it's possible
> > to run it over BTF raw data, like:
> >
> > $ bpftool btf dump file /sys/kernel/btf/vmlinux
> > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> > [3] CONST '(anon)' type_id=2
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
>
> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
[root@ibm-z-107 bpftool]# ./bpftool btf dump file /sys/kernel/btf/vmlinux | head -3
[1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
[3] CONST '(anon)' type_id=2
[root@ibm-z-107 bpftool]# lscpu | grep Endian
Byte Order: Big Endian
thanks,
jirka
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-25 20:03 ` Jiri Olsa
@ 2019-10-26 18:42 ` Jakub Kicinski
0 siblings, 0 replies; 8+ messages in thread
From: Jakub Kicinski @ 2019-10-26 18:42 UTC (permalink / raw)
To: Jiri Olsa
Cc: Jiri Olsa, Alexei Starovoitov, Daniel Borkmann, netdev, bpf,
Andrii Nakryiko, Yonghong Song, Martin KaFai Lau
On Fri, 25 Oct 2019 22:03:51 +0200, Jiri Olsa wrote:
> On Fri, Oct 25, 2019 at 11:39:01AM -0700, Jakub Kicinski wrote:
> > On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote:
> > > The bpftool interface stays the same, but now it's possible
> > > to run it over BTF raw data, like:
> > >
> > > $ bpftool btf dump file /sys/kernel/btf/vmlinux
> > > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> > > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> > > [3] CONST '(anon)' type_id=2
> > >
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> >
> > Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>
> [root@ibm-z-107 bpftool]# ./bpftool btf dump file /sys/kernel/btf/vmlinux | head -3
> [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [3] CONST '(anon)' type_id=2
> [root@ibm-z-107 bpftool]# lscpu | grep Endian
> Byte Order: Big Endian
Thanks for checking! I thought the on-disk format is fixed like the
ELF magic number. But if two bads make a right then all is good ☺️
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] bpftool: Allow to read btf as raw data
2019-10-24 13:30 [PATCH] bpftool: Allow to read btf as raw data Jiri Olsa
` (2 preceding siblings ...)
2019-10-25 18:39 ` Jakub Kicinski
@ 2019-10-25 21:40 ` Daniel Borkmann
3 siblings, 0 replies; 8+ messages in thread
From: Daniel Borkmann @ 2019-10-25 21:40 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, netdev, bpf, Andrii Nakryiko, Yonghong Song,
Martin KaFai Lau, Jakub Kicinski
On Thu, Oct 24, 2019 at 03:30:25PM +0200, Jiri Olsa wrote:
> The bpftool interface stays the same, but now it's possible
> to run it over BTF raw data, like:
>
> $ bpftool btf dump file /sys/kernel/btf/vmlinux
> [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [3] CONST '(anon)' type_id=2
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Applied, thanks!
^ permalink raw reply [flat|nested] 8+ messages in thread
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2019-10-24 13:30 [PATCH] bpftool: Allow to read btf as raw data Jiri Olsa
2019-10-24 17:55 ` Jakub Kicinski
2019-10-25 7:15 ` Jiri Olsa
2019-10-25 5:10 ` Andrii Nakryiko
2019-10-25 18:39 ` Jakub Kicinski
2019-10-25 20:03 ` Jiri Olsa
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