Re: [PATCH bpf-next v3 05/13] tools: libbpf: expose the prog type guessing from section name logic

2018-07-10 Thread Andrey Ignatov 
Jakub Kicinski  [Tue, 2018-07-10 14:43 -0700]:
> libbpf can guess program type based on ELF section names.  As libbpf
> becomes more popular its association between section name strings and
> types becomes more of a standard.  Allow libbpf users to use the same
> logic for matching strings to types, e.g. when the string originates
> from command line.
> 
> Signed-off-by: Jakub Kicinski 
> Reviewed-by: Quentin Monnet 
> ---
> v3 (Andrey):
>  - use -EINVAL error code;
>  - rename helper to libbpf_prog_type_by_name().
> ---
>  tools/lib/bpf/libbpf.c | 43 --
>  tools/lib/bpf/libbpf.h |  3 +++
>  2 files changed, 28 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 38ed3e92e393..42f31eff5f3f 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -2081,23 +2081,31 @@ static const struct {
>  #undef BPF_S_PROG_SEC
>  #undef BPF_SA_PROG_SEC
>  
> -static int bpf_program__identify_section(struct bpf_program *prog)
> +int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
> +  enum bpf_attach_type *expected_attach_type)
>  {
>   int i;
>  
> - if (!prog->section_name)
> - goto err;
> -
> - for (i = 0; i < ARRAY_SIZE(section_names); i++)
> - if (strncmp(prog->section_name, section_names[i].sec,
> - section_names[i].len) == 0)
> - return i;
> + if (!name)
> + return -EINVAL;
>  
> -err:
> - pr_warning("failed to guess program type based on section name %s\n",
> -prog->section_name);
> + for (i = 0; i < ARRAY_SIZE(section_names); i++) {
> + if (strncmp(name, section_names[i].sec, section_names[i].len))
> + continue;
> + *prog_type = section_names[i].prog_type;
> + *expected_attach_type = section_names[i].expected_attach_type;
> + return 0;
> + }
> + return -EINVAL;
> +}
>  
> - return -1;
> +static int
> +bpf_program__identify_section(struct bpf_program *prog,
> +   enum bpf_prog_type *prog_type,
> +   enum bpf_attach_type *expected_attach_type)
> +{
> + return libbpf_prog_type_by_name(prog->section_name, prog_type,
> + expected_attach_type);
>  }
>  
>  int bpf_map__fd(struct bpf_map *map)
> @@ -2230,7 +2238,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr 
> *attr,
>   enum bpf_prog_type prog_type;
>   struct bpf_object *obj;
>   struct bpf_map *map;
> - int section_idx;
>   int err;
>  
>   if (!attr)
> @@ -2252,14 +2259,14 @@ int bpf_prog_load_xattr(const struct 
> bpf_prog_load_attr *attr,
>   prog->prog_ifindex = attr->ifindex;
>   expected_attach_type = attr->expected_attach_type;
>   if (prog_type == BPF_PROG_TYPE_UNSPEC) {
> - section_idx = bpf_program__identify_section(prog);
> - if (section_idx < 0) {
> + err = bpf_program__identify_section(prog, _type,
> + 
> _attach_type);
> + if (err < 0) {
> + pr_warning("failed to guess program type based 
> on section name %s\n",
> +prog->section_name);
>   bpf_object__close(obj);
>   return -EINVAL;
>   }
> - prog_type = section_names[section_idx].prog_type;
> - expected_attach_type =
> - section_names[section_idx].expected_attach_type;
>   }
>  
>   bpf_program__set_type(prog, prog_type);
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 564f4be9bae0..d1ce5c828e2e 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -92,6 +92,9 @@ int bpf_object__set_priv(struct bpf_object *obj, void *priv,
>bpf_object_clear_priv_t clear_priv);
>  void *bpf_object__priv(struct bpf_object *prog);
>  
> +int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
> +  enum bpf_attach_type *expected_attach_type);
> +
>  /* Accessors of bpf_program */
>  struct bpf_program;
>  struct bpf_program *bpf_program__next(struct bpf_program *prog,
> -- 
> 2.17.1
> 

Thanks for changes Jakub!

Acked-by: Andrey Ignatov 

-- 
Andrey Ignatov

[PATCH bpf-next v3 05/13] tools: libbpf: expose the prog type guessing from section name logic

2018-07-10 Thread Jakub Kicinski 
libbpf can guess program type based on ELF section names.  As libbpf
becomes more popular its association between section name strings and
types becomes more of a standard.  Allow libbpf users to use the same
logic for matching strings to types, e.g. when the string originates
from command line.

Signed-off-by: Jakub Kicinski 
Reviewed-by: Quentin Monnet 
---
v3 (Andrey):
 - use -EINVAL error code;
 - rename helper to libbpf_prog_type_by_name().
---
 tools/lib/bpf/libbpf.c | 43 --
 tools/lib/bpf/libbpf.h |  3 +++
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 38ed3e92e393..42f31eff5f3f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2081,23 +2081,31 @@ static const struct {
 #undef BPF_S_PROG_SEC
 #undef BPF_SA_PROG_SEC
 
-static int bpf_program__identify_section(struct bpf_program *prog)
+int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+enum bpf_attach_type *expected_attach_type)
 {
int i;
 
-   if (!prog->section_name)
-   goto err;
-
-   for (i = 0; i < ARRAY_SIZE(section_names); i++)
-   if (strncmp(prog->section_name, section_names[i].sec,
-   section_names[i].len) == 0)
-   return i;
+   if (!name)
+   return -EINVAL;
 
-err:
-   pr_warning("failed to guess program type based on section name %s\n",
-  prog->section_name);
+   for (i = 0; i < ARRAY_SIZE(section_names); i++) {
+   if (strncmp(name, section_names[i].sec, section_names[i].len))
+   continue;
+   *prog_type = section_names[i].prog_type;
+   *expected_attach_type = section_names[i].expected_attach_type;
+   return 0;
+   }
+   return -EINVAL;
+}
 
-   return -1;
+static int
+bpf_program__identify_section(struct bpf_program *prog,
+ enum bpf_prog_type *prog_type,
+ enum bpf_attach_type *expected_attach_type)
+{
+   return libbpf_prog_type_by_name(prog->section_name, prog_type,
+   expected_attach_type);
 }
 
 int bpf_map__fd(struct bpf_map *map)
@@ -2230,7 +2238,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr 
*attr,
enum bpf_prog_type prog_type;
struct bpf_object *obj;
struct bpf_map *map;
-   int section_idx;
int err;
 
if (!attr)
@@ -2252,14 +2259,14 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr 
*attr,
prog->prog_ifindex = attr->ifindex;
expected_attach_type = attr->expected_attach_type;
if (prog_type == BPF_PROG_TYPE_UNSPEC) {
-   section_idx = bpf_program__identify_section(prog);
-   if (section_idx < 0) {
+   err = bpf_program__identify_section(prog, _type,
+   
_attach_type);
+   if (err < 0) {
+   pr_warning("failed to guess program type based 
on section name %s\n",
+  prog->section_name);
bpf_object__close(obj);
return -EINVAL;
}
-   prog_type = section_names[section_idx].prog_type;
-   expected_attach_type =
-   section_names[section_idx].expected_attach_type;
}
 
bpf_program__set_type(prog, prog_type);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 564f4be9bae0..d1ce5c828e2e 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -92,6 +92,9 @@ int bpf_object__set_priv(struct bpf_object *obj, void *priv,
 bpf_object_clear_priv_t clear_priv);
 void *bpf_object__priv(struct bpf_object *prog);
 
+int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+enum bpf_attach_type *expected_attach_type);
+
 /* Accessors of bpf_program */
 struct bpf_program;
 struct bpf_program *bpf_program__next(struct bpf_program *prog,
-- 
2.17.1