* [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file()
@ 2019-10-07 21:22 Andrii Nakryiko
2019-10-07 21:46 ` Stanislav Fomichev
0 siblings, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2019-10-07 21:22 UTC (permalink / raw)
To: bpf, netdev, ast, daniel, sdf
Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
As part of libbpf in 5e61f2707029 ("libbpf: stop enforcing kern_version,
populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API
was removed from libbpf.h header. This broke bpftool, which relied on
that function. This patch fixes the build by switching to newly added
bpf_object__open_file() which provides the same capabilities, but is
official and future-proof API.
Fixes: 5e61f2707029 ("libbpf: stop enforcing kern_version, populate it for users")
Reported-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/bpf/bpftool/main.c | 4 ++--
tools/bpf/bpftool/main.h | 2 +-
tools/bpf/bpftool/prog.c | 22 ++++++++++++----------
3 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 93d008687020..4764581ff9ea 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -27,7 +27,7 @@ bool json_output;
bool show_pinned;
bool block_mount;
bool verifier_logs;
-int bpf_flags;
+bool relaxed_maps;
struct pinned_obj_table prog_table;
struct pinned_obj_table map_table;
@@ -396,7 +396,7 @@ int main(int argc, char **argv)
show_pinned = true;
break;
case 'm':
- bpf_flags = MAPS_RELAX_COMPAT;
+ relaxed_maps = true;
break;
case 'n':
block_mount = true;
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index af9ad56c303a..2899095f8254 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -94,7 +94,7 @@ extern bool json_output;
extern bool show_pinned;
extern bool block_mount;
extern bool verifier_logs;
-extern int bpf_flags;
+extern bool relaxed_maps;
extern struct pinned_obj_table prog_table;
extern struct pinned_obj_table map_table;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 43fdbbfe41bb..8191cd595963 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1092,9 +1092,7 @@ static int do_run(int argc, char **argv)
static int load_with_options(int argc, char **argv, bool first_prog_only)
{
struct bpf_object_load_attr load_attr = { 0 };
- struct bpf_object_open_attr open_attr = {
- .prog_type = BPF_PROG_TYPE_UNSPEC,
- };
+ enum bpf_prog_type prog_type = BPF_PROG_TYPE_UNSPEC;
enum bpf_attach_type expected_attach_type;
struct map_replace *map_replace = NULL;
struct bpf_program *prog = NULL, *pos;
@@ -1105,11 +1103,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
const char *pinfile;
unsigned int i, j;
__u32 ifindex = 0;
+ const char *file;
int idx, err;
+ LIBBPF_OPTS(bpf_object_open_opts, open_opts,
+ .relaxed_maps = relaxed_maps,
+ );
+
if (!REQ_ARGS(2))
return -1;
- open_attr.file = GET_ARG();
+ file = GET_ARG();
pinfile = GET_ARG();
while (argc) {
@@ -1118,7 +1121,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
NEXT_ARG();
- if (open_attr.prog_type != BPF_PROG_TYPE_UNSPEC) {
+ if (prog_type != BPF_PROG_TYPE_UNSPEC) {
p_err("program type already specified");
goto err_free_reuse_maps;
}
@@ -1135,8 +1138,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
strcat(type, *argv);
strcat(type, "/");
- err = libbpf_prog_type_by_name(type,
- &open_attr.prog_type,
+ err = libbpf_prog_type_by_name(type, &prog_type,
&expected_attach_type);
free(type);
if (err < 0)
@@ -1224,16 +1226,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
set_max_rlimit();
- obj = __bpf_object__open_xattr(&open_attr, bpf_flags);
+ obj = bpf_object__open_file(file, &open_opts);
if (IS_ERR_OR_NULL(obj)) {
p_err("failed to open object file");
goto err_free_reuse_maps;
}
bpf_object__for_each_program(pos, obj) {
- enum bpf_prog_type prog_type = open_attr.prog_type;
+ enum bpf_prog_type prog_type = prog_type;
- if (open_attr.prog_type == BPF_PROG_TYPE_UNSPEC) {
+ if (prog_type == BPF_PROG_TYPE_UNSPEC) {
const char *sec_name = bpf_program__title(pos, false);
err = libbpf_prog_type_by_name(sec_name, &prog_type,
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file()
2019-10-07 21:22 [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file() Andrii Nakryiko
@ 2019-10-07 21:46 ` Stanislav Fomichev
2019-10-07 21:50 ` Andrii Nakryiko
0 siblings, 1 reply; 5+ messages in thread
From: Stanislav Fomichev @ 2019-10-07 21:46 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: bpf, netdev, ast, daniel, sdf, andrii.nakryiko, kernel-team
On 10/07, Andrii Nakryiko wrote:
> As part of libbpf in 5e61f2707029 ("libbpf: stop enforcing kern_version,
> populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API
> was removed from libbpf.h header. This broke bpftool, which relied on
> that function. This patch fixes the build by switching to newly added
> bpf_object__open_file() which provides the same capabilities, but is
> official and future-proof API.
>
> Fixes: 5e61f2707029 ("libbpf: stop enforcing kern_version, populate it for users")
> Reported-by: Stanislav Fomichev <sdf@google.com>
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> ---
> tools/bpf/bpftool/main.c | 4 ++--
> tools/bpf/bpftool/main.h | 2 +-
> tools/bpf/bpftool/prog.c | 22 ++++++++++++----------
> 3 files changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
> index 93d008687020..4764581ff9ea 100644
> --- a/tools/bpf/bpftool/main.c
> +++ b/tools/bpf/bpftool/main.c
> @@ -27,7 +27,7 @@ bool json_output;
> bool show_pinned;
> bool block_mount;
> bool verifier_logs;
> -int bpf_flags;
> +bool relaxed_maps;
> struct pinned_obj_table prog_table;
> struct pinned_obj_table map_table;
>
> @@ -396,7 +396,7 @@ int main(int argc, char **argv)
> show_pinned = true;
> break;
> case 'm':
> - bpf_flags = MAPS_RELAX_COMPAT;
> + relaxed_maps = true;
> break;
> case 'n':
> block_mount = true;
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> index af9ad56c303a..2899095f8254 100644
> --- a/tools/bpf/bpftool/main.h
> +++ b/tools/bpf/bpftool/main.h
> @@ -94,7 +94,7 @@ extern bool json_output;
> extern bool show_pinned;
> extern bool block_mount;
> extern bool verifier_logs;
> -extern int bpf_flags;
> +extern bool relaxed_maps;
> extern struct pinned_obj_table prog_table;
> extern struct pinned_obj_table map_table;
>
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index 43fdbbfe41bb..8191cd595963 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1092,9 +1092,7 @@ static int do_run(int argc, char **argv)
> static int load_with_options(int argc, char **argv, bool first_prog_only)
> {
> struct bpf_object_load_attr load_attr = { 0 };
> - struct bpf_object_open_attr open_attr = {
> - .prog_type = BPF_PROG_TYPE_UNSPEC,
> - };
> + enum bpf_prog_type prog_type = BPF_PROG_TYPE_UNSPEC;
> enum bpf_attach_type expected_attach_type;
> struct map_replace *map_replace = NULL;
> struct bpf_program *prog = NULL, *pos;
> @@ -1105,11 +1103,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> const char *pinfile;
> unsigned int i, j;
> __u32 ifindex = 0;
> + const char *file;
> int idx, err;
>
> + LIBBPF_OPTS(bpf_object_open_opts, open_opts,
> + .relaxed_maps = relaxed_maps,
> + );
> +
> if (!REQ_ARGS(2))
> return -1;
> - open_attr.file = GET_ARG();
> + file = GET_ARG();
> pinfile = GET_ARG();
>
> while (argc) {
> @@ -1118,7 +1121,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
>
> NEXT_ARG();
>
> - if (open_attr.prog_type != BPF_PROG_TYPE_UNSPEC) {
> + if (prog_type != BPF_PROG_TYPE_UNSPEC) {
> p_err("program type already specified");
> goto err_free_reuse_maps;
> }
> @@ -1135,8 +1138,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> strcat(type, *argv);
> strcat(type, "/");
>
> - err = libbpf_prog_type_by_name(type,
> - &open_attr.prog_type,
> + err = libbpf_prog_type_by_name(type, &prog_type,
> &expected_attach_type);
> free(type);
> if (err < 0)
> @@ -1224,16 +1226,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
>
> set_max_rlimit();
>
> - obj = __bpf_object__open_xattr(&open_attr, bpf_flags);
> + obj = bpf_object__open_file(file, &open_opts);
> if (IS_ERR_OR_NULL(obj)) {
> p_err("failed to open object file");
> goto err_free_reuse_maps;
> }
>
> bpf_object__for_each_program(pos, obj) {
> - enum bpf_prog_type prog_type = open_attr.prog_type;
> + enum bpf_prog_type prog_type = prog_type;
Are you sure it works that way?
$ cat tmp.c
#include <stdio.h>
int main()
{
int x = 1;
printf("outer x=%d\n", x);
{
int x = x;
printf("inner x=%d\n", x);
}
return 0;
}
$ gcc tmp.c && ./a.out
outer x=1
inner x=0
Other than that:
Reviewed-by: Stanislav Fomichev <sdf@google.com>
>
> - if (open_attr.prog_type == BPF_PROG_TYPE_UNSPEC) {
> + if (prog_type == BPF_PROG_TYPE_UNSPEC) {
> const char *sec_name = bpf_program__title(pos, false);
>
> err = libbpf_prog_type_by_name(sec_name, &prog_type,
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file()
2019-10-07 21:46 ` Stanislav Fomichev
@ 2019-10-07 21:50 ` Andrii Nakryiko
2019-10-07 23:00 ` Andrii Nakryiko
0 siblings, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2019-10-07 21:50 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Stanislav Fomichev, Kernel Team
On Mon, Oct 7, 2019 at 2:46 PM Stanislav Fomichev <sdf@fomichev.me> wrote:
>
> On 10/07, Andrii Nakryiko wrote:
> > As part of libbpf in 5e61f2707029 ("libbpf: stop enforcing kern_version,
> > populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API
> > was removed from libbpf.h header. This broke bpftool, which relied on
> > that function. This patch fixes the build by switching to newly added
> > bpf_object__open_file() which provides the same capabilities, but is
> > official and future-proof API.
> >
> > Fixes: 5e61f2707029 ("libbpf: stop enforcing kern_version, populate it for users")
> > Reported-by: Stanislav Fomichev <sdf@google.com>
> > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > ---
> > tools/bpf/bpftool/main.c | 4 ++--
> > tools/bpf/bpftool/main.h | 2 +-
> > tools/bpf/bpftool/prog.c | 22 ++++++++++++----------
> > 3 files changed, 15 insertions(+), 13 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
> > index 93d008687020..4764581ff9ea 100644
> > --- a/tools/bpf/bpftool/main.c
> > +++ b/tools/bpf/bpftool/main.c
> > @@ -27,7 +27,7 @@ bool json_output;
> > bool show_pinned;
> > bool block_mount;
> > bool verifier_logs;
> > -int bpf_flags;
> > +bool relaxed_maps;
> > struct pinned_obj_table prog_table;
> > struct pinned_obj_table map_table;
> >
> > @@ -396,7 +396,7 @@ int main(int argc, char **argv)
> > show_pinned = true;
> > break;
> > case 'm':
> > - bpf_flags = MAPS_RELAX_COMPAT;
> > + relaxed_maps = true;
> > break;
> > case 'n':
> > block_mount = true;
> > diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> > index af9ad56c303a..2899095f8254 100644
> > --- a/tools/bpf/bpftool/main.h
> > +++ b/tools/bpf/bpftool/main.h
> > @@ -94,7 +94,7 @@ extern bool json_output;
> > extern bool show_pinned;
> > extern bool block_mount;
> > extern bool verifier_logs;
> > -extern int bpf_flags;
> > +extern bool relaxed_maps;
> > extern struct pinned_obj_table prog_table;
> > extern struct pinned_obj_table map_table;
> >
> > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> > index 43fdbbfe41bb..8191cd595963 100644
> > --- a/tools/bpf/bpftool/prog.c
> > +++ b/tools/bpf/bpftool/prog.c
> > @@ -1092,9 +1092,7 @@ static int do_run(int argc, char **argv)
> > static int load_with_options(int argc, char **argv, bool first_prog_only)
> > {
> > struct bpf_object_load_attr load_attr = { 0 };
> > - struct bpf_object_open_attr open_attr = {
> > - .prog_type = BPF_PROG_TYPE_UNSPEC,
> > - };
> > + enum bpf_prog_type prog_type = BPF_PROG_TYPE_UNSPEC;
> > enum bpf_attach_type expected_attach_type;
> > struct map_replace *map_replace = NULL;
> > struct bpf_program *prog = NULL, *pos;
> > @@ -1105,11 +1103,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > const char *pinfile;
> > unsigned int i, j;
> > __u32 ifindex = 0;
> > + const char *file;
> > int idx, err;
> >
> > + LIBBPF_OPTS(bpf_object_open_opts, open_opts,
> > + .relaxed_maps = relaxed_maps,
> > + );
> > +
> > if (!REQ_ARGS(2))
> > return -1;
> > - open_attr.file = GET_ARG();
> > + file = GET_ARG();
> > pinfile = GET_ARG();
> >
> > while (argc) {
> > @@ -1118,7 +1121,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> >
> > NEXT_ARG();
> >
> > - if (open_attr.prog_type != BPF_PROG_TYPE_UNSPEC) {
> > + if (prog_type != BPF_PROG_TYPE_UNSPEC) {
> > p_err("program type already specified");
> > goto err_free_reuse_maps;
> > }
> > @@ -1135,8 +1138,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > strcat(type, *argv);
> > strcat(type, "/");
> >
> > - err = libbpf_prog_type_by_name(type,
> > - &open_attr.prog_type,
> > + err = libbpf_prog_type_by_name(type, &prog_type,
> > &expected_attach_type);
> > free(type);
> > if (err < 0)
> > @@ -1224,16 +1226,16 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> >
> > set_max_rlimit();
> >
> > - obj = __bpf_object__open_xattr(&open_attr, bpf_flags);
> > + obj = bpf_object__open_file(file, &open_opts);
> > if (IS_ERR_OR_NULL(obj)) {
> > p_err("failed to open object file");
> > goto err_free_reuse_maps;
> > }
> >
> > bpf_object__for_each_program(pos, obj) {
> > - enum bpf_prog_type prog_type = open_attr.prog_type;
> > + enum bpf_prog_type prog_type = prog_type;
> Are you sure it works that way?
Oh, I did this pretty mechanically, didn't notice I'm shadowing. In
either case I'd like to avoid shadowing, so I'll rename one of them,
good catch!
>
> $ cat tmp.c
> #include <stdio.h>
>
> int main()
> {
> int x = 1;
> printf("outer x=%d\n", x);
>
> {
> int x = x;
> printf("inner x=%d\n", x);
> }
>
> return 0;
> }
>
> $ gcc tmp.c && ./a.out
> outer x=1
> inner x=0
>
> Other than that:
> Reviewed-by: Stanislav Fomichev <sdf@google.com>
>
> >
> > - if (open_attr.prog_type == BPF_PROG_TYPE_UNSPEC) {
> > + if (prog_type == BPF_PROG_TYPE_UNSPEC) {
> > const char *sec_name = bpf_program__title(pos, false);
> >
> > err = libbpf_prog_type_by_name(sec_name, &prog_type,
> > --
> > 2.17.1
> >
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file()
2019-10-07 21:50 ` Andrii Nakryiko
@ 2019-10-07 23:00 ` Andrii Nakryiko
2019-10-08 15:26 ` Stanislav Fomichev
0 siblings, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2019-10-07 23:00 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Stanislav Fomichev, Kernel Team
-- Andrii
On Mon, Oct 7, 2019 at 2:50 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Mon, Oct 7, 2019 at 2:46 PM Stanislav Fomichev <sdf@fomichev.me> wrote:
> >
> > On 10/07, Andrii Nakryiko wrote:
> > > As part of libbpf in 5e61f2707029 ("libbpf: stop enforcing kern_version,
> > > populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API
> > > was removed from libbpf.h header. This broke bpftool, which relied on
> > > that function. This patch fixes the build by switching to newly added
> > > bpf_object__open_file() which provides the same capabilities, but is
> > > official and future-proof API.
> > >
> > > Fixes: 5e61f2707029 ("libbpf: stop enforcing kern_version, populate it for users")
> > > Reported-by: Stanislav Fomichev <sdf@google.com>
> > > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > > ---
> > > tools/bpf/bpftool/main.c | 4 ++--
> > > tools/bpf/bpftool/main.h | 2 +-
> > > tools/bpf/bpftool/prog.c | 22 ++++++++++++----------
> > > 3 files changed, 15 insertions(+), 13 deletions(-)
> > >
[...]
> > > --- a/tools/bpf/bpftool/prog.c
> > > +++ b/tools/bpf/bpftool/prog.c
> > > @@ -1092,9 +1092,7 @@ static int do_run(int argc, char **argv)
> > > static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > {
> > > struct bpf_object_load_attr load_attr = { 0 };
> > > - struct bpf_object_open_attr open_attr = {
> > > - .prog_type = BPF_PROG_TYPE_UNSPEC,
> > > - };
> > > + enum bpf_prog_type prog_type = BPF_PROG_TYPE_UNSPEC;
> > > enum bpf_attach_type expected_attach_type;
> > > struct map_replace *map_replace = NULL;
[...]
> > >
> > > bpf_object__for_each_program(pos, obj) {
> > > - enum bpf_prog_type prog_type = open_attr.prog_type;
> > > + enum bpf_prog_type prog_type = prog_type;
> > Are you sure it works that way?
>
> Oh, I did this pretty mechanically, didn't notice I'm shadowing. In
> either case I'd like to avoid shadowing, so I'll rename one of them,
> good catch!
>
> >
> > $ cat tmp.c
> > #include <stdio.h>
> >
> > int main()
> > {
> > int x = 1;
> > printf("outer x=%d\n", x);
> >
> > {
> > int x = x;
It's amazing `int x = x;` is compiled successfully when there is no x
in outer scope. And it's also amazing that it's doing the wrong thing
when there is a shadowed variable in outer scope. I can't imagine the
case where this will be a meaningful behavior...
> > printf("inner x=%d\n", x);
> > }
> >
> > return 0;
> > }
> >
> > $ gcc tmp.c && ./a.out
> > outer x=1
> > inner x=0
> >
> > Other than that:
> > Reviewed-by: Stanislav Fomichev <sdf@google.com>
> >
> > >
> > > - if (open_attr.prog_type == BPF_PROG_TYPE_UNSPEC) {
> > > + if (prog_type == BPF_PROG_TYPE_UNSPEC) {
> > > const char *sec_name = bpf_program__title(pos, false);
> > >
> > > err = libbpf_prog_type_by_name(sec_name, &prog_type,
> > > --
> > > 2.17.1
> > >
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file()
2019-10-07 23:00 ` Andrii Nakryiko
@ 2019-10-08 15:26 ` Stanislav Fomichev
0 siblings, 0 replies; 5+ messages in thread
From: Stanislav Fomichev @ 2019-10-08 15:26 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Stanislav Fomichev, Kernel Team
On 10/07, Andrii Nakryiko wrote:
> -- Andrii
>
> On Mon, Oct 7, 2019 at 2:50 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Mon, Oct 7, 2019 at 2:46 PM Stanislav Fomichev <sdf@fomichev.me> wrote:
> > >
> > > On 10/07, Andrii Nakryiko wrote:
> > > > As part of libbpf in 5e61f2707029 ("libbpf: stop enforcing kern_version,
> > > > populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API
> > > > was removed from libbpf.h header. This broke bpftool, which relied on
> > > > that function. This patch fixes the build by switching to newly added
> > > > bpf_object__open_file() which provides the same capabilities, but is
> > > > official and future-proof API.
> > > >
> > > > Fixes: 5e61f2707029 ("libbpf: stop enforcing kern_version, populate it for users")
> > > > Reported-by: Stanislav Fomichev <sdf@google.com>
> > > > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > > > ---
> > > > tools/bpf/bpftool/main.c | 4 ++--
> > > > tools/bpf/bpftool/main.h | 2 +-
> > > > tools/bpf/bpftool/prog.c | 22 ++++++++++++----------
> > > > 3 files changed, 15 insertions(+), 13 deletions(-)
> > > >
>
> [...]
>
> > > > --- a/tools/bpf/bpftool/prog.c
> > > > +++ b/tools/bpf/bpftool/prog.c
> > > > @@ -1092,9 +1092,7 @@ static int do_run(int argc, char **argv)
> > > > static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > > {
> > > > struct bpf_object_load_attr load_attr = { 0 };
> > > > - struct bpf_object_open_attr open_attr = {
> > > > - .prog_type = BPF_PROG_TYPE_UNSPEC,
> > > > - };
> > > > + enum bpf_prog_type prog_type = BPF_PROG_TYPE_UNSPEC;
> > > > enum bpf_attach_type expected_attach_type;
> > > > struct map_replace *map_replace = NULL;
>
> [...]
>
> > > >
> > > > bpf_object__for_each_program(pos, obj) {
> > > > - enum bpf_prog_type prog_type = open_attr.prog_type;
> > > > + enum bpf_prog_type prog_type = prog_type;
> > > Are you sure it works that way?
> >
> > Oh, I did this pretty mechanically, didn't notice I'm shadowing. In
> > either case I'd like to avoid shadowing, so I'll rename one of them,
> > good catch!
> >
> > >
> > > $ cat tmp.c
> > > #include <stdio.h>
> > >
> > > int main()
> > > {
> > > int x = 1;
> > > printf("outer x=%d\n", x);
> > >
> > > {
> > > int x = x;
>
> It's amazing `int x = x;` is compiled successfully when there is no x
> in outer scope. And it's also amazing that it's doing the wrong thing
> when there is a shadowed variable in outer scope. I can't imagine the
> case where this will be a meaningful behavior...
Enjoy your daily dose of undefined behavior :-D
> > > printf("inner x=%d\n", x);
> > > }
> > >
> > > return 0;
> > > }
> > >
> > > $ gcc tmp.c && ./a.out
> > > outer x=1
> > > inner x=0
> > >
> > > Other than that:
> > > Reviewed-by: Stanislav Fomichev <sdf@google.com>
> > >
> > > >
> > > > - if (open_attr.prog_type == BPF_PROG_TYPE_UNSPEC) {
> > > > + if (prog_type == BPF_PROG_TYPE_UNSPEC) {
> > > > const char *sec_name = bpf_program__title(pos, false);
> > > >
> > > > err = libbpf_prog_type_by_name(sec_name, &prog_type,
> > > > --
> > > > 2.17.1
> > > >
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-10-08 15:26 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-07 21:22 [PATCH bpf-next] bpftool: fix bpftool build by switching to bpf_object__open_file() Andrii Nakryiko
2019-10-07 21:46 ` Stanislav Fomichev
2019-10-07 21:50 ` Andrii Nakryiko
2019-10-07 23:00 ` Andrii Nakryiko
2019-10-08 15:26 ` Stanislav Fomichev
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