* [PATCH bpf-next 0/2] tools/btf: extends libbpf APIs to work with btf w/o kernel
@ 2019-02-05 19:48 Andrii Nakryiko
2019-02-05 19:48 ` [PATCH bpf-next 1/2] btf: separate btf creation and loading Andrii Nakryiko
2019-02-05 19:48 ` [PATCH bpf-next 2/2] btf: expose API to work with raw btf data Andrii Nakryiko
0 siblings, 2 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-02-05 19:48 UTC (permalink / raw)
To: songliubraving, yhs, ast, kafai, netdev, daniel, andrii.nakryiko
Cc: Andrii Nakryiko
This patchset changes existing btf__new() API call to only load and initialize
struct btf, while exposing new btf__load() API to attempt to load and validate
BTF in kernel. It also adds ability to copy raw BTF data out of struct btf for
further processing by external applications.
This makes utilizing libbpf's APIs that don't require kernel facilities (e.g.,
btf_dedup) simpler and more natural from external application.
Andrii Nakryiko (2):
btf: separate btf creation and loading
btf: expose API to work with raw btf data
tools/lib/bpf/btf.c | 63 +++++++++++++++++++++++++---------------
tools/lib/bpf/btf.h | 3 ++
tools/lib/bpf/libbpf.c | 2 +-
tools/lib/bpf/libbpf.map | 3 ++
4 files changed, 46 insertions(+), 25 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next 1/2] btf: separate btf creation and loading
2019-02-05 19:48 [PATCH bpf-next 0/2] tools/btf: extends libbpf APIs to work with btf w/o kernel Andrii Nakryiko
@ 2019-02-05 19:48 ` Andrii Nakryiko
2019-02-05 21:25 ` Yonghong Song
2019-02-05 19:48 ` [PATCH bpf-next 2/2] btf: expose API to work with raw btf data Andrii Nakryiko
1 sibling, 1 reply; 6+ messages in thread
From: Andrii Nakryiko @ 2019-02-05 19:48 UTC (permalink / raw)
To: songliubraving, yhs, ast, kafai, netdev, daniel, andrii.nakryiko
Cc: Andrii Nakryiko
This change splits out previous btf__new functionality of constructing
struct btf and loading it into kernel into two:
- btf__new() just creates and initializes struct btf
- btf__load() attempts to load existing struct btf into kernel
btf__free will still close BTF fd, if it was ever loaded successfully
into kernel.
This change allows users of libbpf to manipulate BTF using its API,
without the need to unnecessarily load it into kernel.
One of the intended use cases is pahole using libbpf to do DWARF to BTF
conversion and deduplication using libbpf, while handling ELF sections
overwrites and other concerns on its own.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
---
tools/lib/bpf/btf.c | 53 ++++++++++++++++++++++------------------
tools/lib/bpf/btf.h | 1 +
tools/lib/bpf/libbpf.c | 2 +-
tools/lib/bpf/libbpf.map | 1 +
4 files changed, 32 insertions(+), 25 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 4949f8840bda..065d51fa63e5 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -366,8 +366,6 @@ void btf__free(struct btf *btf)
struct btf *btf__new(__u8 *data, __u32 size)
{
- __u32 log_buf_size = 0;
- char *log_buf = NULL;
struct btf *btf;
int err;
@@ -377,15 +375,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
btf->fd = -1;
- log_buf = malloc(BPF_LOG_BUF_SIZE);
- if (!log_buf) {
- err = -ENOMEM;
- goto done;
- }
-
- *log_buf = 0;
- log_buf_size = BPF_LOG_BUF_SIZE;
-
btf->data = malloc(size);
if (!btf->data) {
err = -ENOMEM;
@@ -395,17 +384,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
memcpy(btf->data, data, size);
btf->data_size = size;
- btf->fd = bpf_load_btf(btf->data, btf->data_size,
- log_buf, log_buf_size, false);
-
- if (btf->fd == -1) {
- err = -errno;
- pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
- if (log_buf && *log_buf)
- pr_warning("%s\n", log_buf);
- goto done;
- }
-
err = btf_parse_hdr(btf);
if (err)
goto done;
@@ -417,8 +395,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
err = btf_parse_type_sec(btf);
done:
- free(log_buf);
-
if (err) {
btf__free(btf);
return ERR_PTR(err);
@@ -427,6 +403,35 @@ struct btf *btf__new(__u8 *data, __u32 size)
return btf;
}
+int btf__load(struct btf* btf) {
+ __u32 log_buf_size = BPF_LOG_BUF_SIZE;
+ char *log_buf = NULL;
+
+ if (btf->fd >= 0) {
+ return -EEXIST;
+ }
+
+ log_buf = malloc(log_buf_size);
+ if (!log_buf)
+ return -ENOMEM;
+
+ *log_buf = 0;
+
+ btf->fd = bpf_load_btf(btf->data, btf->data_size,
+ log_buf, log_buf_size, false);
+ if (btf->fd < 0) {
+ btf->fd = -errno;
+ pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
+ if (*log_buf)
+ pr_warning("%s\n", log_buf);
+ goto done;
+ }
+
+done:
+ free(log_buf);
+ return btf->fd;
+}
+
int btf__fd(const struct btf *btf)
{
return btf->fd;
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 25a9d2db035d..e8410887f93a 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -57,6 +57,7 @@ struct btf_ext_header {
LIBBPF_API void btf__free(struct btf *btf);
LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
+LIBBPF_API int btf__load(struct btf* btf);
LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
const char *type_name);
LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 47969aa0faf8..75b82c1cfc72 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -835,7 +835,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
obj->efile.maps_shndx = idx;
else if (strcmp(name, BTF_ELF_SEC) == 0) {
obj->btf = btf__new(data->d_buf, data->d_size);
- if (IS_ERR(obj->btf)) {
+ if (IS_ERR(obj->btf) || btf__load(obj->btf) < 0) {
pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
BTF_ELF_SEC, PTR_ERR(obj->btf));
obj->btf = NULL;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 89c1149e32ee..ffa1fe044f6a 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -134,6 +134,7 @@ LIBBPF_0.0.2 {
bpf_object__find_map_fd_by_name;
bpf_get_link_xdp_id;
btf__dedup;
+ btf__load;
btf__get_map_kv_tids;
btf__get_nr_types;
btf__get_strings;
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH bpf-next 2/2] btf: expose API to work with raw btf data
2019-02-05 19:48 [PATCH bpf-next 0/2] tools/btf: extends libbpf APIs to work with btf w/o kernel Andrii Nakryiko
2019-02-05 19:48 ` [PATCH bpf-next 1/2] btf: separate btf creation and loading Andrii Nakryiko
@ 2019-02-05 19:48 ` Andrii Nakryiko
2019-02-05 22:01 ` Yonghong Song
1 sibling, 1 reply; 6+ messages in thread
From: Andrii Nakryiko @ 2019-02-05 19:48 UTC (permalink / raw)
To: songliubraving, yhs, ast, kafai, netdev, daniel, andrii.nakryiko
Cc: Andrii Nakryiko
This patch exposes two new APIs btf__get_raw_data_size() and
btf__get_raw_data() that allows to get a copy of raw BTF data out of
struct btf. This is useful for external programs that need to manipulate
raw data, e.g., pahole using btf__dedup() to deduplicate BTF type info
and then writing it back to file.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
---
tools/lib/bpf/btf.c | 10 ++++++++++
tools/lib/bpf/btf.h | 2 ++
tools/lib/bpf/libbpf.map | 2 ++
3 files changed, 14 insertions(+)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 065d51fa63e5..6491d440c9a7 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -437,6 +437,16 @@ int btf__fd(const struct btf *btf)
return btf->fd;
}
+__u32 btf__get_raw_data_size(const struct btf *btf)
+{
+ return btf->data_size;
+}
+
+void btf__get_raw_data(const struct btf *btf, char *data)
+{
+ memcpy(data, btf->data, btf->data_size);
+}
+
void btf__get_strings(const struct btf *btf, const char **strings,
__u32 *str_len)
{
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index e8410887f93a..d46f680b9416 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -66,6 +66,8 @@ LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
LIBBPF_API int btf__fd(const struct btf *btf);
+LIBBPF_API __u32 btf__get_raw_data_size(const struct btf *btf);
+LIBBPF_API void btf__get_raw_data(const struct btf *btf, char *data);
LIBBPF_API void btf__get_strings(const struct btf *btf, const char **strings,
__u32 *str_len);
LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index ffa1fe044f6a..873a26cd714d 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -137,6 +137,8 @@ LIBBPF_0.0.2 {
btf__load;
btf__get_map_kv_tids;
btf__get_nr_types;
+ btf__get_raw_data;
+ btf__get_raw_data_size;
btf__get_strings;
btf_ext__free;
btf_ext__func_info_rec_size;
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 1/2] btf: separate btf creation and loading
2019-02-05 19:48 ` [PATCH bpf-next 1/2] btf: separate btf creation and loading Andrii Nakryiko
@ 2019-02-05 21:25 ` Yonghong Song
2019-02-05 22:34 ` Andrii Nakryiko
0 siblings, 1 reply; 6+ messages in thread
From: Yonghong Song @ 2019-02-05 21:25 UTC (permalink / raw)
To: Andrii Nakryiko, Song Liu, Alexei Starovoitov, Martin Lau,
netdev, daniel, andrii.nakryiko
On 2/5/19 11:48 AM, Andrii Nakryiko wrote:
> This change splits out previous btf__new functionality of constructing
> struct btf and loading it into kernel into two:
> - btf__new() just creates and initializes struct btf
> - btf__load() attempts to load existing struct btf into kernel
>
> btf__free will still close BTF fd, if it was ever loaded successfully
> into kernel.
>
> This change allows users of libbpf to manipulate BTF using its API,
> without the need to unnecessarily load it into kernel.
>
> One of the intended use cases is pahole using libbpf to do DWARF to BTF
> conversion and deduplication using libbpf, while handling ELF sections
> overwrites and other concerns on its own.
>
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> Acked-by: Song Liu <songliubraving@fb.com>
> ---
> tools/lib/bpf/btf.c | 53 ++++++++++++++++++++++------------------
> tools/lib/bpf/btf.h | 1 +
> tools/lib/bpf/libbpf.c | 2 +-
> tools/lib/bpf/libbpf.map | 1 +
> 4 files changed, 32 insertions(+), 25 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 4949f8840bda..065d51fa63e5 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -366,8 +366,6 @@ void btf__free(struct btf *btf)
>
> struct btf *btf__new(__u8 *data, __u32 size)
> {
> - __u32 log_buf_size = 0;
> - char *log_buf = NULL;
> struct btf *btf;
> int err;
>
> @@ -377,15 +375,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
>
> btf->fd = -1;
>
> - log_buf = malloc(BPF_LOG_BUF_SIZE);
> - if (!log_buf) {
> - err = -ENOMEM;
> - goto done;
> - }
> -
> - *log_buf = 0;
> - log_buf_size = BPF_LOG_BUF_SIZE;
> -
> btf->data = malloc(size);
> if (!btf->data) {
> err = -ENOMEM;
> @@ -395,17 +384,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
> memcpy(btf->data, data, size);
> btf->data_size = size;
>
> - btf->fd = bpf_load_btf(btf->data, btf->data_size,
> - log_buf, log_buf_size, false);
> -
> - if (btf->fd == -1) {
> - err = -errno;
> - pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
> - if (log_buf && *log_buf)
> - pr_warning("%s\n", log_buf);
> - goto done;
> - }
> -
> err = btf_parse_hdr(btf);
> if (err)
> goto done;
> @@ -417,8 +395,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
> err = btf_parse_type_sec(btf);
>
> done:
> - free(log_buf);
> -
> if (err) {
> btf__free(btf);
> return ERR_PTR(err);
> @@ -427,6 +403,35 @@ struct btf *btf__new(__u8 *data, __u32 size)
> return btf;
> }
>
> +int btf__load(struct btf* btf) {
> + __u32 log_buf_size = BPF_LOG_BUF_SIZE;
> + char *log_buf = NULL;
> +
> + if (btf->fd >= 0) {
> + return -EEXIST;
> + }
> +
> + log_buf = malloc(log_buf_size);
> + if (!log_buf)
> + return -ENOMEM;
> +
> + *log_buf = 0;
> +
> + btf->fd = bpf_load_btf(btf->data, btf->data_size,
> + log_buf, log_buf_size, false);
> + if (btf->fd < 0) {
> + btf->fd = -errno;
Why you set btf->fd = -errno? Do you have any intended use for it later.
If not, I would still prefer the existing value -1. This will be
consistent with all other fd field convention in libbpf.
> + pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
> + if (*log_buf)
> + pr_warning("%s\n", log_buf);
> + goto done;
> + }
> +
> +done:
> + free(log_buf);
> + return btf->fd;
> +}
> +
> int btf__fd(const struct btf *btf)
> {
> return btf->fd;
> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
> index 25a9d2db035d..e8410887f93a 100644
> --- a/tools/lib/bpf/btf.h
> +++ b/tools/lib/bpf/btf.h
> @@ -57,6 +57,7 @@ struct btf_ext_header {
>
> LIBBPF_API void btf__free(struct btf *btf);
> LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
> +LIBBPF_API int btf__load(struct btf* btf);
> LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
> const char *type_name);
> LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 47969aa0faf8..75b82c1cfc72 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -835,7 +835,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
> obj->efile.maps_shndx = idx;
> else if (strcmp(name, BTF_ELF_SEC) == 0) {
> obj->btf = btf__new(data->d_buf, data->d_size);
> - if (IS_ERR(obj->btf)) {
> + if (IS_ERR(obj->btf) || btf__load(obj->btf) < 0) {
> pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
> BTF_ELF_SEC, PTR_ERR(obj->btf));
> obj->btf = NULL;
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 89c1149e32ee..ffa1fe044f6a 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -134,6 +134,7 @@ LIBBPF_0.0.2 {
> bpf_object__find_map_fd_by_name;
> bpf_get_link_xdp_id;
> btf__dedup;
> + btf__load;
Maybe put btf__load after btf__get_strings based on alphabetical order.
With the above changes,
> btf__get_map_kv_tids;
> btf__get_nr_types;
> btf__get_strings;
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 2/2] btf: expose API to work with raw btf data
2019-02-05 19:48 ` [PATCH bpf-next 2/2] btf: expose API to work with raw btf data Andrii Nakryiko
@ 2019-02-05 22:01 ` Yonghong Song
0 siblings, 0 replies; 6+ messages in thread
From: Yonghong Song @ 2019-02-05 22:01 UTC (permalink / raw)
To: Andrii Nakryiko, Song Liu, Alexei Starovoitov, Martin Lau,
netdev, daniel, andrii.nakryiko
On 2/5/19 11:48 AM, Andrii Nakryiko wrote:
> This patch exposes two new APIs btf__get_raw_data_size() and
> btf__get_raw_data() that allows to get a copy of raw BTF data out of
> struct btf. This is useful for external programs that need to manipulate
> raw data, e.g., pahole using btf__dedup() to deduplicate BTF type info
> and then writing it back to file.
>
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
> ---
> tools/lib/bpf/btf.c | 10 ++++++++++
> tools/lib/bpf/btf.h | 2 ++
> tools/lib/bpf/libbpf.map | 2 ++
> 3 files changed, 14 insertions(+)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 065d51fa63e5..6491d440c9a7 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -437,6 +437,16 @@ int btf__fd(const struct btf *btf)
> return btf->fd;
> }
>
> +__u32 btf__get_raw_data_size(const struct btf *btf)
> +{
> + return btf->data_size;
> +}
> +
> +void btf__get_raw_data(const struct btf *btf, char *data)
> +{
> + memcpy(data, btf->data, btf->data_size);
> +}
> +
> void btf__get_strings(const struct btf *btf, const char **strings,
> __u32 *str_len)
> {
> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
> index e8410887f93a..d46f680b9416 100644
> --- a/tools/lib/bpf/btf.h
> +++ b/tools/lib/bpf/btf.h
> @@ -66,6 +66,8 @@ LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
> LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
> LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
> LIBBPF_API int btf__fd(const struct btf *btf);
> +LIBBPF_API __u32 btf__get_raw_data_size(const struct btf *btf);
> +LIBBPF_API void btf__get_raw_data(const struct btf *btf, char *data);
> LIBBPF_API void btf__get_strings(const struct btf *btf, const char **strings,
> __u32 *str_len);
> LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index ffa1fe044f6a..873a26cd714d 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -137,6 +137,8 @@ LIBBPF_0.0.2 {
> btf__load;
> btf__get_map_kv_tids;
> btf__get_nr_types;
> + btf__get_raw_data;
> + btf__get_raw_data_size;
> btf__get_strings;
> btf_ext__free;
> btf_ext__func_info_rec_size;
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 1/2] btf: separate btf creation and loading
2019-02-05 21:25 ` Yonghong Song
@ 2019-02-05 22:34 ` Andrii Nakryiko
0 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2019-02-05 22:34 UTC (permalink / raw)
To: Yonghong Song
Cc: Andrii Nakryiko, Song Liu, Alexei Starovoitov, Martin Lau,
netdev, daniel
On Tue, Feb 5, 2019 at 1:25 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 2/5/19 11:48 AM, Andrii Nakryiko wrote:
> > This change splits out previous btf__new functionality of constructing
> > struct btf and loading it into kernel into two:
> > - btf__new() just creates and initializes struct btf
> > - btf__load() attempts to load existing struct btf into kernel
> >
> > btf__free will still close BTF fd, if it was ever loaded successfully
> > into kernel.
> >
> > This change allows users of libbpf to manipulate BTF using its API,
> > without the need to unnecessarily load it into kernel.
> >
> > One of the intended use cases is pahole using libbpf to do DWARF to BTF
> > conversion and deduplication using libbpf, while handling ELF sections
> > overwrites and other concerns on its own.
> >
> > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > Acked-by: Song Liu <songliubraving@fb.com>
> > ---
> > tools/lib/bpf/btf.c | 53 ++++++++++++++++++++++------------------
> > tools/lib/bpf/btf.h | 1 +
> > tools/lib/bpf/libbpf.c | 2 +-
> > tools/lib/bpf/libbpf.map | 1 +
> > 4 files changed, 32 insertions(+), 25 deletions(-)
> >
> > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> > index 4949f8840bda..065d51fa63e5 100644
> > --- a/tools/lib/bpf/btf.c
> > +++ b/tools/lib/bpf/btf.c
> > @@ -366,8 +366,6 @@ void btf__free(struct btf *btf)
> >
> > struct btf *btf__new(__u8 *data, __u32 size)
> > {
> > - __u32 log_buf_size = 0;
> > - char *log_buf = NULL;
> > struct btf *btf;
> > int err;
> >
> > @@ -377,15 +375,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
> >
> > btf->fd = -1;
> >
> > - log_buf = malloc(BPF_LOG_BUF_SIZE);
> > - if (!log_buf) {
> > - err = -ENOMEM;
> > - goto done;
> > - }
> > -
> > - *log_buf = 0;
> > - log_buf_size = BPF_LOG_BUF_SIZE;
> > -
> > btf->data = malloc(size);
> > if (!btf->data) {
> > err = -ENOMEM;
> > @@ -395,17 +384,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
> > memcpy(btf->data, data, size);
> > btf->data_size = size;
> >
> > - btf->fd = bpf_load_btf(btf->data, btf->data_size,
> > - log_buf, log_buf_size, false);
> > -
> > - if (btf->fd == -1) {
> > - err = -errno;
> > - pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
> > - if (log_buf && *log_buf)
> > - pr_warning("%s\n", log_buf);
> > - goto done;
> > - }
> > -
> > err = btf_parse_hdr(btf);
> > if (err)
> > goto done;
> > @@ -417,8 +395,6 @@ struct btf *btf__new(__u8 *data, __u32 size)
> > err = btf_parse_type_sec(btf);
> >
> > done:
> > - free(log_buf);
> > -
> > if (err) {
> > btf__free(btf);
> > return ERR_PTR(err);
> > @@ -427,6 +403,35 @@ struct btf *btf__new(__u8 *data, __u32 size)
> > return btf;
> > }
> >
> > +int btf__load(struct btf* btf) {
> > + __u32 log_buf_size = BPF_LOG_BUF_SIZE;
> > + char *log_buf = NULL;
> > +
> > + if (btf->fd >= 0) {
> > + return -EEXIST;
> > + }
> > +
> > + log_buf = malloc(log_buf_size);
> > + if (!log_buf)
> > + return -ENOMEM;
> > +
> > + *log_buf = 0;
> > +
> > + btf->fd = bpf_load_btf(btf->data, btf->data_size,
> > + log_buf, log_buf_size, false);
> > + if (btf->fd < 0) {
> > + btf->fd = -errno;
>
> Why you set btf->fd = -errno? Do you have any intended use for it later.
> If not, I would still prefer the existing value -1. This will be
> consistent with all other fd field convention in libbpf.
I though it would be convenient to get created fd back from
btf_load(), but I don't have strong preferences. In any case, we have
btf__get_fd() to get it back, so I will change btf__load() to return
just error code.
>
> > + pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
> > + if (*log_buf)
> > + pr_warning("%s\n", log_buf);
> > + goto done;
> > + }
> > +
> > +done:
> > + free(log_buf);
> > + return btf->fd;
> > +}
> > +
> > int btf__fd(const struct btf *btf)
> > {
> > return btf->fd;
> > diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
> > index 25a9d2db035d..e8410887f93a 100644
> > --- a/tools/lib/bpf/btf.h
> > +++ b/tools/lib/bpf/btf.h
> > @@ -57,6 +57,7 @@ struct btf_ext_header {
> >
> > LIBBPF_API void btf__free(struct btf *btf);
> > LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
> > +LIBBPF_API int btf__load(struct btf* btf);
> > LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
> > const char *type_name);
> > LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 47969aa0faf8..75b82c1cfc72 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -835,7 +835,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
> > obj->efile.maps_shndx = idx;
> > else if (strcmp(name, BTF_ELF_SEC) == 0) {
> > obj->btf = btf__new(data->d_buf, data->d_size);
> > - if (IS_ERR(obj->btf)) {
> > + if (IS_ERR(obj->btf) || btf__load(obj->btf) < 0) {
> > pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
> > BTF_ELF_SEC, PTR_ERR(obj->btf));
> > obj->btf = NULL;
> > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> > index 89c1149e32ee..ffa1fe044f6a 100644
> > --- a/tools/lib/bpf/libbpf.map
> > +++ b/tools/lib/bpf/libbpf.map
> > @@ -134,6 +134,7 @@ LIBBPF_0.0.2 {
> > bpf_object__find_map_fd_by_name;
> > bpf_get_link_xdp_id;
> > btf__dedup;
> > + btf__load;
>
> Maybe put btf__load after btf__get_strings based on alphabetical order.
> With the above changes,
Yep, will fix to be alphabetically sorted.
>
>
> > btf__get_map_kv_tids;
> > btf__get_nr_types;
> > btf__get_strings;
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-02-05 22:35 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-02-05 19:48 [PATCH bpf-next 0/2] tools/btf: extends libbpf APIs to work with btf w/o kernel Andrii Nakryiko
2019-02-05 19:48 ` [PATCH bpf-next 1/2] btf: separate btf creation and loading Andrii Nakryiko
2019-02-05 21:25 ` Yonghong Song
2019-02-05 22:34 ` Andrii Nakryiko
2019-02-05 19:48 ` [PATCH bpf-next 2/2] btf: expose API to work with raw btf data Andrii Nakryiko
2019-02-05 22:01 ` Yonghong Song
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