Em Wed, Jul 01, 2015 at 02:14:08AM +0000, Wang Nan escreveu:
> This patch introduces accessors for user of libbpf to retrieve section
> name and fd of a opened/loaded eBPF program. 'struct bpf_prog_handler'
> is used for that purpose. Accessors of programs section name and file
> descriptor are provided. Set/get private data are also impelmented.
>
> Signed-off-by: Wang Nan <[email protected]>
> Acked-by: Alexei Starovoitov <[email protected]>
> ---
> tools/lib/bpf/libbpf.c | 82
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/libbpf.h | 25 +++++++++++++++
> 2 files changed, 107 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 33452f8..e4c5f07 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -98,6 +98,10 @@ struct bpf_program {
> int nr_reloc;
>
> int fd;
> +
> + struct bpf_object *obj;
> + void *priv;
> + bpf_program_clear_priv_t clear_priv;
> };
>
> struct bpf_object {
> @@ -150,6 +154,12 @@ static void bpf_program__clear(struct bpf_program *prog)
> if (!prog)
> return;
>
> + if (prog->clear_priv)
> + prog->clear_priv(prog, prog->priv);
> +
> + prog->priv = NULL;
> + prog->clear_priv = NULL;
> +
> bpf_program__unload(prog);
> zfree(&prog->section_name);
> zfree(&prog->insns);
> @@ -211,6 +221,7 @@ bpf_program__new(struct bpf_object *obj, void *data,
> size_t size,
> prog->insns_cnt * sizeof(struct bpf_insn));
> prog->idx = idx;
> prog->fd = -1;
> + prog->obj = obj;
>
> return prog;
> out:
> @@ -924,3 +935,74 @@ void bpf_object__close(struct bpf_object *obj)
>
> free(obj);
> }
> +
> +struct bpf_program *
> +bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
> +{
> + size_t idx;
> +
> + if (!obj->programs)
> + return NULL;
> + /* First handler */
> + if (prev == NULL)
> + return &obj->programs[0];
> +
> + if (prev->obj != obj) {
> + pr_warning("error: program handler doesn't match object\n");
> + return NULL;
> + }
> +
> + idx = (prev - obj->programs) + 1;
> + if (idx >= obj->nr_programs)
> + return NULL;
> + return &obj->programs[idx];
> +}
> +
> +int bpf_program__set_private(struct bpf_program *prog,
> + void *priv,
> + bpf_program_clear_priv_t clear_priv)
> +{
> + if (prog->priv && prog->clear_priv)
> + prog->clear_priv(prog, prog->priv);
> +
> + prog->priv = priv;
> + prog->clear_priv = clear_priv;
> + return 0;
> +}
> +
> +int bpf_program__get_private(struct bpf_program *prog, void **ppriv)
> +{
> + *ppriv = prog->priv;
> + return 0;
> +}
> +
> +int bpf_program__get_title(struct bpf_program *prog,
> + const char **ptitle, bool dup)
> +{
> + const char *title;
> +
> + if (!ptitle)
> + return -EINVAL;
> +
> + title = prog->section_name;
> + if (dup) {
> + title = strdup(title);
> + if (!title) {
> + pr_warning("failed to strdup program title\n");
> + *ptitle = NULL;
> + return -ENOMEM;
> + }
> + }
> +
> + *ptitle = title;
> + return 0;
> +}
> +
> +int bpf_program__get_fd(struct bpf_program *prog, int *pfd)
> +{
> + if (!pfd)
> + return -EINVAL;
> +
> + *pfd = prog->fd;
> + return 0;
Why not:
int bpf_program__fd(struct bpf_program *prog)
{
return prog->fd;
}
Or plain ditch completely this function and go ahead and use:
prog->fd;
I see, you don't export the bpf_program struct definition, but
then why not return it straight away?
Ditto for bpf_program__get_title()
- Arnaldo
> +}
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 3e69600..9e0e102 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -9,6 +9,7 @@
> #define __BPF_LIBBPF_H
>
> #include <stdio.h>
> +#include <stdbool.h>
>
> /*
> * In include/linux/compiler-gcc.h, __printf is defined. However
> @@ -34,6 +35,30 @@ void bpf_object__close(struct bpf_object *object);
> int bpf_object__load(struct bpf_object *obj);
> int bpf_object__unload(struct bpf_object *obj);
>
> +/* Accessors of bpf_program. */
> +struct bpf_program;
> +struct bpf_program *bpf_program__next(struct bpf_program *prog,
> + struct bpf_object *obj);
> +
> +#define bpf_object__for_each_program(pos, obj) \
> + for ((pos) = bpf_program__next(NULL, (obj)); \
> + (pos) != NULL; \
> + (pos) = bpf_program__next((pos), (obj)))
> +
> +typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
> + void *);
> +
> +int bpf_program__set_private(struct bpf_program *prog, void *priv,
> + bpf_program_clear_priv_t clear_priv);
> +
> +int bpf_program__get_private(struct bpf_program *prog,
> + void **ppriv);
> +
> +int bpf_program__get_title(struct bpf_program *prog,
> + const char **ptitle, bool dup);
> +
> +int bpf_program__get_fd(struct bpf_program *prog, int *pfd);
> +
> /*
> * We don't need __attribute__((packed)) now since it is
> * unnecessary for 'bpf_map_def' because they are all aligned.
> --
> 1.8.3.4
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