This patch introduces btf__resolve_type() function and exports two
existing functions from libbpf. btf__resolve_type follows modifier
types like const and typedef until it hits a type which actually takes
up memory, and then returns it. This function follows similar pattern
to btf__resolve_size but instead of computing size, it just returns
the type.
These functions will be used in the followig patch which parses
information inside array of `struct btf_type *`. btf_name_by_offset is
used for printing variable names.
Signed-off-by: Okash Khawaja <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
---
tools/lib/bpf/btf.c | 65 ++++++++++++++++++++++++++++++++++++----------------
tools/lib/bpf/btf.h | 3 ++
2 files changed, 48 insertions(+), 20 deletions(-)
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -17,6 +17,11 @@
#define BTF_MAX_NR_TYPES 65535
+#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
+ ((k) == BTF_KIND_VOLATILE) || \
+ ((k) == BTF_KIND_CONST) || \
+ ((k) == BTF_KIND_RESTRICT))
+
static struct btf_type btf_void;
struct btf {
@@ -33,14 +38,6 @@ struct btf {
int fd;
};
-static const char *btf_name_by_offset(const struct btf *btf, uint32_t offset)
-{
- if (offset < btf->hdr->str_len)
- return &btf->strings[offset];
- else
- return NULL;
-}
-
static int btf_add_type(struct btf *btf, struct btf_type *t)
{
if (btf->types_size - btf->nr_types < 2) {
@@ -190,15 +187,6 @@ static int btf_parse_type_sec(struct btf
return 0;
}
-static const struct btf_type *btf_type_by_id(const struct btf *btf,
- uint32_t type_id)
-{
- if (type_id > btf->nr_types)
- return NULL;
-
- return btf->types[type_id];
-}
-
static bool btf_type_is_void(const struct btf_type *t)
{
return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
@@ -234,7 +222,7 @@ int64_t btf__resolve_size(const struct b
int64_t size = -1;
int i;
- t = btf_type_by_id(btf, type_id);
+ t = btf__type_by_id(btf, type_id);
for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
i++) {
size = btf_type_size(t);
@@ -259,7 +247,7 @@ int64_t btf__resolve_size(const struct b
return -EINVAL;
}
- t = btf_type_by_id(btf, type_id);
+ t = btf__type_by_id(btf, type_id);
}
if (size < 0)
@@ -271,6 +259,26 @@ int64_t btf__resolve_size(const struct b
return nelems * size;
}
+int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id)
+{
+ const struct btf_type *t;
+ int depth = 0;
+
+ t = btf__type_by_id(btf, type_id);
+ while (depth < MAX_RESOLVE_DEPTH &&
+ !btf_type_is_void_or_null(t) &&
+ IS_MODIFIER(BTF_INFO_KIND(t->info))) {
+ type_id = t->type;
+ t = btf__type_by_id(btf, type_id);
+ depth++;
+ }
+
+ if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
+ return -EINVAL;
+
+ return type_id;
+}
+
int32_t btf__find_by_name(const struct btf *btf, const char *type_name)
{
uint32_t i;
@@ -280,7 +288,7 @@ int32_t btf__find_by_name(const struct b
for (i = 1; i <= btf->nr_types; i++) {
const struct btf_type *t = btf->types[i];
- const char *name = btf_name_by_offset(btf, t->name_off);
+ const char *name = btf__name_by_offset(btf, t->name_off);
if (name && !strcmp(type_name, name))
return i;
@@ -371,3 +379,20 @@ int btf__fd(const struct btf *btf)
{
return btf->fd;
}
+
+const char *btf__name_by_offset(const struct btf *btf, uint32_t offset)
+{
+ if (offset < btf->hdr->str_len)
+ return &btf->strings[offset];
+ else
+ return NULL;
+}
+
+const struct btf_type *btf__type_by_id(const struct btf *btf,
+ uint32_t type_id)
+{
+ if (type_id > btf->nr_types)
+ return NULL;
+
+ return btf->types[type_id];
+}
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -17,6 +17,9 @@ void btf__free(struct btf *btf);
struct btf *btf__new(uint8_t *data, uint32_t size, btf_print_fn_t err_log);
int32_t btf__find_by_name(const struct btf *btf, const char *type_name);
int64_t btf__resolve_size(const struct btf *btf, uint32_t type_id);
+int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id);
int btf__fd(const struct btf *btf);
+const char *btf__name_by_offset(const struct btf *btf, uint32_t offset);
+const struct btf_type *btf__type_by_id(const struct btf *btf, uint32_t type_id);
#endif
> On Jun 20, 2018, at 1:30 PM, Okash Khawaja <[email protected]> wrote:
>
> This patch introduces btf__resolve_type() function and exports two
> existing functions from libbpf. btf__resolve_type follows modifier
> types like const and typedef until it hits a type which actually takes
> up memory, and then returns it. This function follows similar pattern
> to btf__resolve_size but instead of computing size, it just returns
> the type.
>
> These functions will be used in the followig patch which parses
> information inside array of `struct btf_type *`. btf_name_by_offset is
> used for printing variable names.
>
> Signed-off-by: Okash Khawaja <[email protected]>
> Acked-by: Martin KaFai Lau <[email protected]>
>
> ---
> tools/lib/bpf/btf.c | 65 ++++++++++++++++++++++++++++++++++++----------------
> tools/lib/bpf/btf.h | 3 ++
> 2 files changed, 48 insertions(+), 20 deletions(-)
>
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -17,6 +17,11 @@
>
> #define BTF_MAX_NR_TYPES 65535
>
> +#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
> + ((k) == BTF_KIND_VOLATILE) || \
> + ((k) == BTF_KIND_CONST) || \
> + ((k) == BTF_KIND_RESTRICT))
> +
> static struct btf_type btf_void;
>
> struct btf {
> @@ -33,14 +38,6 @@ struct btf {
> int fd;
> };
>
> -static const char *btf_name_by_offset(const struct btf *btf, uint32_t offset)
> -{
> - if (offset < btf->hdr->str_len)
> - return &btf->strings[offset];
> - else
> - return NULL;
> -}
> -
> static int btf_add_type(struct btf *btf, struct btf_type *t)
> {
> if (btf->types_size - btf->nr_types < 2) {
> @@ -190,15 +187,6 @@ static int btf_parse_type_sec(struct btf
> return 0;
> }
>
> -static const struct btf_type *btf_type_by_id(const struct btf *btf,
> - uint32_t type_id)
> -{
> - if (type_id > btf->nr_types)
> - return NULL;
> -
> - return btf->types[type_id];
> -}
nit: Why do we need to move these two functions to later of the file?
Other than this,
Acked-by: Song Liu <[email protected]>
> -
> static bool btf_type_is_void(const struct btf_type *t)
> {
> return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
> @@ -234,7 +222,7 @@ int64_t btf__resolve_size(const struct b
> int64_t size = -1;
> int i;
>
> - t = btf_type_by_id(btf, type_id);
> + t = btf__type_by_id(btf, type_id);
> for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
> i++) {
> size = btf_type_size(t);
> @@ -259,7 +247,7 @@ int64_t btf__resolve_size(const struct b
> return -EINVAL;
> }
>
> - t = btf_type_by_id(btf, type_id);
> + t = btf__type_by_id(btf, type_id);
> }
>
> if (size < 0)
> @@ -271,6 +259,26 @@ int64_t btf__resolve_size(const struct b
> return nelems * size;
> }
>
> +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id)
> +{
> + const struct btf_type *t;
> + int depth = 0;
> +
> + t = btf__type_by_id(btf, type_id);
> + while (depth < MAX_RESOLVE_DEPTH &&
> + !btf_type_is_void_or_null(t) &&
> + IS_MODIFIER(BTF_INFO_KIND(t->info))) {
> + type_id = t->type;
> + t = btf__type_by_id(btf, type_id);
> + depth++;
> + }
> +
> + if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
> + return -EINVAL;
> +
> + return type_id;
> +}
> +
> int32_t btf__find_by_name(const struct btf *btf, const char *type_name)
> {
> uint32_t i;
> @@ -280,7 +288,7 @@ int32_t btf__find_by_name(const struct b
>
> for (i = 1; i <= btf->nr_types; i++) {
> const struct btf_type *t = btf->types[i];
> - const char *name = btf_name_by_offset(btf, t->name_off);
> + const char *name = btf__name_by_offset(btf, t->name_off);
>
> if (name && !strcmp(type_name, name))
> return i;
> @@ -371,3 +379,20 @@ int btf__fd(const struct btf *btf)
> {
> return btf->fd;
> }
> +
> +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset)
> +{
> + if (offset < btf->hdr->str_len)
> + return &btf->strings[offset];
> + else
> + return NULL;
> +}
> +
> +const struct btf_type *btf__type_by_id(const struct btf *btf,
> + uint32_t type_id)
> +{
> + if (type_id > btf->nr_types)
> + return NULL;
> +
> + return btf->types[type_id];
> +}
> --- a/tools/lib/bpf/btf.h
> +++ b/tools/lib/bpf/btf.h
> @@ -17,6 +17,9 @@ void btf__free(struct btf *btf);
> struct btf *btf__new(uint8_t *data, uint32_t size, btf_print_fn_t err_log);
> int32_t btf__find_by_name(const struct btf *btf, const char *type_name);
> int64_t btf__resolve_size(const struct btf *btf, uint32_t type_id);
> +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id);
> int btf__fd(const struct btf *btf);
> +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset);
> +const struct btf_type *btf__type_by_id(const struct btf *btf, uint32_t type_id);
>
> #endif
>
On Wed, Jun 20, 2018 at 11:40:19PM +0100, Song Liu wrote:
>
>
> > On Jun 20, 2018, at 1:30 PM, Okash Khawaja <[email protected]> wrote:
> >
> > This patch introduces btf__resolve_type() function and exports two
> > existing functions from libbpf. btf__resolve_type follows modifier
> > types like const and typedef until it hits a type which actually takes
> > up memory, and then returns it. This function follows similar pattern
> > to btf__resolve_size but instead of computing size, it just returns
> > the type.
> >
> > These functions will be used in the followig patch which parses
> > information inside array of `struct btf_type *`. btf_name_by_offset is
> > used for printing variable names.
> >
> > Signed-off-by: Okash Khawaja <[email protected]>
> > Acked-by: Martin KaFai Lau <[email protected]>
> >
> > ---
> > tools/lib/bpf/btf.c | 65 ++++++++++++++++++++++++++++++++++++----------------
> > tools/lib/bpf/btf.h | 3 ++
> > 2 files changed, 48 insertions(+), 20 deletions(-)
> >
> > --- a/tools/lib/bpf/btf.c
> > +++ b/tools/lib/bpf/btf.c
> > @@ -17,6 +17,11 @@
> >
> > #define BTF_MAX_NR_TYPES 65535
> >
> > +#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
> > + ((k) == BTF_KIND_VOLATILE) || \
> > + ((k) == BTF_KIND_CONST) || \
> > + ((k) == BTF_KIND_RESTRICT))
> > +
> > static struct btf_type btf_void;
> >
> > struct btf {
> > @@ -33,14 +38,6 @@ struct btf {
> > int fd;
> > };
> >
> > -static const char *btf_name_by_offset(const struct btf *btf, uint32_t offset)
> > -{
> > - if (offset < btf->hdr->str_len)
> > - return &btf->strings[offset];
> > - else
> > - return NULL;
> > -}
> > -
> > static int btf_add_type(struct btf *btf, struct btf_type *t)
> > {
> > if (btf->types_size - btf->nr_types < 2) {
> > @@ -190,15 +187,6 @@ static int btf_parse_type_sec(struct btf
> > return 0;
> > }
> >
> > -static const struct btf_type *btf_type_by_id(const struct btf *btf,
> > - uint32_t type_id)
> > -{
> > - if (type_id > btf->nr_types)
> > - return NULL;
> > -
> > - return btf->types[type_id];
> > -}
>
> nit: Why do we need to move these two functions to later of the file?
No real reason. It looked like this file was following a convention of
keeping statics together. I'll put them back in place if no one objects.
>
> Other than this,
>
> Acked-by: Song Liu <[email protected]>
Thanks
>
> > -
> > static bool btf_type_is_void(const struct btf_type *t)
> > {
> > return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
> > @@ -234,7 +222,7 @@ int64_t btf__resolve_size(const struct b
> > int64_t size = -1;
> > int i;
> >
> > - t = btf_type_by_id(btf, type_id);
> > + t = btf__type_by_id(btf, type_id);
> > for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
> > i++) {
> > size = btf_type_size(t);
> > @@ -259,7 +247,7 @@ int64_t btf__resolve_size(const struct b
> > return -EINVAL;
> > }
> >
> > - t = btf_type_by_id(btf, type_id);
> > + t = btf__type_by_id(btf, type_id);
> > }
> >
> > if (size < 0)
> > @@ -271,6 +259,26 @@ int64_t btf__resolve_size(const struct b
> > return nelems * size;
> > }
> >
> > +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id)
> > +{
> > + const struct btf_type *t;
> > + int depth = 0;
> > +
> > + t = btf__type_by_id(btf, type_id);
> > + while (depth < MAX_RESOLVE_DEPTH &&
> > + !btf_type_is_void_or_null(t) &&
> > + IS_MODIFIER(BTF_INFO_KIND(t->info))) {
> > + type_id = t->type;
> > + t = btf__type_by_id(btf, type_id);
> > + depth++;
> > + }
> > +
> > + if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
> > + return -EINVAL;
> > +
> > + return type_id;
> > +}
> > +
> > int32_t btf__find_by_name(const struct btf *btf, const char *type_name)
> > {
> > uint32_t i;
> > @@ -280,7 +288,7 @@ int32_t btf__find_by_name(const struct b
> >
> > for (i = 1; i <= btf->nr_types; i++) {
> > const struct btf_type *t = btf->types[i];
> > - const char *name = btf_name_by_offset(btf, t->name_off);
> > + const char *name = btf__name_by_offset(btf, t->name_off);
> >
> > if (name && !strcmp(type_name, name))
> > return i;
> > @@ -371,3 +379,20 @@ int btf__fd(const struct btf *btf)
> > {
> > return btf->fd;
> > }
> > +
> > +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset)
> > +{
> > + if (offset < btf->hdr->str_len)
> > + return &btf->strings[offset];
> > + else
> > + return NULL;
> > +}
> > +
> > +const struct btf_type *btf__type_by_id(const struct btf *btf,
> > + uint32_t type_id)
> > +{
> > + if (type_id > btf->nr_types)
> > + return NULL;
> > +
> > + return btf->types[type_id];
> > +}
> > --- a/tools/lib/bpf/btf.h
> > +++ b/tools/lib/bpf/btf.h
> > @@ -17,6 +17,9 @@ void btf__free(struct btf *btf);
> > struct btf *btf__new(uint8_t *data, uint32_t size, btf_print_fn_t err_log);
> > int32_t btf__find_by_name(const struct btf *btf, const char *type_name);
> > int64_t btf__resolve_size(const struct btf *btf, uint32_t type_id);
> > +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id);
> > int btf__fd(const struct btf *btf);
> > +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset);
> > +const struct btf_type *btf__type_by_id(const struct btf *btf, uint32_t type_id);
> >
> > #endif
> >
>
> On Jun 20, 2018, at 3:48 PM, Okash Khawaja <[email protected]> wrote:
>
> On Wed, Jun 20, 2018 at 11:40:19PM +0100, Song Liu wrote:
>>
>>
>>> On Jun 20, 2018, at 1:30 PM, Okash Khawaja <[email protected]> wrote:
>>>
>>> This patch introduces btf__resolve_type() function and exports two
>>> existing functions from libbpf. btf__resolve_type follows modifier
>>> types like const and typedef until it hits a type which actually takes
>>> up memory, and then returns it. This function follows similar pattern
>>> to btf__resolve_size but instead of computing size, it just returns
>>> the type.
>>>
>>> These functions will be used in the followig patch which parses
>>> information inside array of `struct btf_type *`. btf_name_by_offset is
>>> used for printing variable names.
>>>
>>> Signed-off-by: Okash Khawaja <[email protected]>
>>> Acked-by: Martin KaFai Lau <[email protected]>
>>>
>>> ---
>>> tools/lib/bpf/btf.c | 65 ++++++++++++++++++++++++++++++++++++----------------
>>> tools/lib/bpf/btf.h | 3 ++
>>> 2 files changed, 48 insertions(+), 20 deletions(-)
>>>
>>> --- a/tools/lib/bpf/btf.c
>>> +++ b/tools/lib/bpf/btf.c
>>> @@ -17,6 +17,11 @@
>>>
>>> #define BTF_MAX_NR_TYPES 65535
>>>
>>> +#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \
>>> + ((k) == BTF_KIND_VOLATILE) || \
>>> + ((k) == BTF_KIND_CONST) || \
>>> + ((k) == BTF_KIND_RESTRICT))
>>> +
>>> static struct btf_type btf_void;
>>>
>>> struct btf {
>>> @@ -33,14 +38,6 @@ struct btf {
>>> int fd;
>>> };
>>>
>>> -static const char *btf_name_by_offset(const struct btf *btf, uint32_t offset)
>>> -{
>>> - if (offset < btf->hdr->str_len)
>>> - return &btf->strings[offset];
>>> - else
>>> - return NULL;
>>> -}
>>> -
>>> static int btf_add_type(struct btf *btf, struct btf_type *t)
>>> {
>>> if (btf->types_size - btf->nr_types < 2) {
>>> @@ -190,15 +187,6 @@ static int btf_parse_type_sec(struct btf
>>> return 0;
>>> }
>>>
>>> -static const struct btf_type *btf_type_by_id(const struct btf *btf,
>>> - uint32_t type_id)
>>> -{
>>> - if (type_id > btf->nr_types)
>>> - return NULL;
>>> -
>>> - return btf->types[type_id];
>>> -}
>>
>> nit: Why do we need to move these two functions to later of the file?
> No real reason. It looked like this file was following a convention of
> keeping statics together. I'll put them back in place if no one objects.
I see. Let's keep this patch as-is then.
Thanks,
Song
>
>>
>> Other than this,
>>
>> Acked-by: Song Liu <[email protected]>
> Thanks
>
>>
>>> -
>>> static bool btf_type_is_void(const struct btf_type *t)
>>> {
>>> return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
>>> @@ -234,7 +222,7 @@ int64_t btf__resolve_size(const struct b
>>> int64_t size = -1;
>>> int i;
>>>
>>> - t = btf_type_by_id(btf, type_id);
>>> + t = btf__type_by_id(btf, type_id);
>>> for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
>>> i++) {
>>> size = btf_type_size(t);
>>> @@ -259,7 +247,7 @@ int64_t btf__resolve_size(const struct b
>>> return -EINVAL;
>>> }
>>>
>>> - t = btf_type_by_id(btf, type_id);
>>> + t = btf__type_by_id(btf, type_id);
>>> }
>>>
>>> if (size < 0)
>>> @@ -271,6 +259,26 @@ int64_t btf__resolve_size(const struct b
>>> return nelems * size;
>>> }
>>>
>>> +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id)
>>> +{
>>> + const struct btf_type *t;
>>> + int depth = 0;
>>> +
>>> + t = btf__type_by_id(btf, type_id);
>>> + while (depth < MAX_RESOLVE_DEPTH &&
>>> + !btf_type_is_void_or_null(t) &&
>>> + IS_MODIFIER(BTF_INFO_KIND(t->info))) {
>>> + type_id = t->type;
>>> + t = btf__type_by_id(btf, type_id);
>>> + depth++;
>>> + }
>>> +
>>> + if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
>>> + return -EINVAL;
>>> +
>>> + return type_id;
>>> +}
>>> +
>>> int32_t btf__find_by_name(const struct btf *btf, const char *type_name)
>>> {
>>> uint32_t i;
>>> @@ -280,7 +288,7 @@ int32_t btf__find_by_name(const struct b
>>>
>>> for (i = 1; i <= btf->nr_types; i++) {
>>> const struct btf_type *t = btf->types[i];
>>> - const char *name = btf_name_by_offset(btf, t->name_off);
>>> + const char *name = btf__name_by_offset(btf, t->name_off);
>>>
>>> if (name && !strcmp(type_name, name))
>>> return i;
>>> @@ -371,3 +379,20 @@ int btf__fd(const struct btf *btf)
>>> {
>>> return btf->fd;
>>> }
>>> +
>>> +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset)
>>> +{
>>> + if (offset < btf->hdr->str_len)
>>> + return &btf->strings[offset];
>>> + else
>>> + return NULL;
>>> +}
>>> +
>>> +const struct btf_type *btf__type_by_id(const struct btf *btf,
>>> + uint32_t type_id)
>>> +{
>>> + if (type_id > btf->nr_types)
>>> + return NULL;
>>> +
>>> + return btf->types[type_id];
>>> +}
>>> --- a/tools/lib/bpf/btf.h
>>> +++ b/tools/lib/bpf/btf.h
>>> @@ -17,6 +17,9 @@ void btf__free(struct btf *btf);
>>> struct btf *btf__new(uint8_t *data, uint32_t size, btf_print_fn_t err_log);
>>> int32_t btf__find_by_name(const struct btf *btf, const char *type_name);
>>> int64_t btf__resolve_size(const struct btf *btf, uint32_t type_id);
>>> +int32_t btf__resolve_type(const struct btf *btf, uint32_t type_id);
>>> int btf__fd(const struct btf *btf);
>>> +const char *btf__name_by_offset(const struct btf *btf, uint32_t offset);
>>> +const struct btf_type *btf__type_by_id(const struct btf *btf, uint32_t type_id);
>>>
>>> #endif