lkml.org 
[lkml]   [2022]   [May]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    Subject[RFC PATCH bpf-next 3/9] libbpf: Add support for rstat progs and links
    From
    Add support to attach "cgroup_subsys/rstat" programs to a subsystem by
    calling bpf_program__attach_subsys. Currently, only CGROUP_SUBSYS_RSTAT
    programs are supported for attachment to subsystems.

    Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
    ---
    tools/lib/bpf/bpf.c | 3 +++
    tools/lib/bpf/bpf.h | 3 +++
    tools/lib/bpf/libbpf.c | 35 +++++++++++++++++++++++++++++++++++
    tools/lib/bpf/libbpf.h | 3 +++
    tools/lib/bpf/libbpf.map | 1 +
    5 files changed, 45 insertions(+)

    diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
    index cf27251adb92..abfff17cfa07 100644
    --- a/tools/lib/bpf/bpf.c
    +++ b/tools/lib/bpf/bpf.c
    @@ -863,6 +863,9 @@ int bpf_link_create(int prog_fd, int target_fd,
    if (!OPTS_ZEROED(opts, kprobe_multi))
    return libbpf_err(-EINVAL);
    break;
    + case BPF_CGROUP_SUBSYS_RSTAT:
    + attr.link_create.cgroup_subsys.name = ptr_to_u64(OPTS_GET(opts, cgroup_subsys.name, 0));
    + break;
    default:
    if (!OPTS_ZEROED(opts, flags))
    return libbpf_err(-EINVAL);
    diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
    index f4b4afb6d4ba..384767a9ffd3 100644
    --- a/tools/lib/bpf/bpf.h
    +++ b/tools/lib/bpf/bpf.h
    @@ -413,6 +413,9 @@ struct bpf_link_create_opts {
    struct {
    __u64 bpf_cookie;
    } perf_event;
    + struct {
    + const char *name;
    + } cgroup_subsys;
    struct {
    __u32 flags;
    __u32 cnt;
    diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
    index 809fe209cdcc..56380953df55 100644
    --- a/tools/lib/bpf/libbpf.c
    +++ b/tools/lib/bpf/libbpf.c
    @@ -8715,6 +8715,7 @@ static const struct bpf_sec_def section_defs[] = {
    SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
    SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE),
    SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
    + SEC_DEF("cgroup_subsys/rstat", CGROUP_SUBSYS_RSTAT, 0, SEC_NONE),
    };

    static size_t custom_sec_def_cnt;
    @@ -10957,6 +10958,40 @@ static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_l
    return libbpf_get_error(*link);
    }

    +struct bpf_link *bpf_program__attach_subsys(const struct bpf_program *prog,
    + const char *subsys_name)
    +{
    + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, lopts,
    + .cgroup_subsys.name = subsys_name);
    + struct bpf_link *link = NULL;
    + char errmsg[STRERR_BUFSIZE];
    + int err, prog_fd, link_fd;
    +
    + prog_fd = bpf_program__fd(prog);
    + if (prog_fd < 0) {
    + pr_warn("prog '%s': can't attach before loaded\n", prog->name);
    + return libbpf_err_ptr(-EINVAL);
    + }
    +
    + link = calloc(1, sizeof(*link));
    + if (!link)
    + return libbpf_err_ptr(-ENOMEM);
    + link->detach = &bpf_link__detach_fd;
    +
    + link_fd = bpf_link_create(prog_fd, 0, BPF_CGROUP_SUBSYS_RSTAT, &lopts);
    + if (link_fd < 0) {
    + err = -errno;
    + pr_warn("prog '%s': failed to attach: %s\n",
    + prog->name, libbpf_strerror_r(err, errmsg,
    + sizeof(errmsg)));
    + free(link);
    + return libbpf_err_ptr(err);
    + }
    +
    + link->fd = link_fd;
    + return link;
    +}
    +
    struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
    {
    struct bpf_link *link = NULL;
    diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
    index 05dde85e19a6..eddbffcd39f7 100644
    --- a/tools/lib/bpf/libbpf.h
    +++ b/tools/lib/bpf/libbpf.h
    @@ -537,6 +537,9 @@ bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex);
    LIBBPF_API struct bpf_link *
    bpf_program__attach_freplace(const struct bpf_program *prog,
    int target_fd, const char *attach_func_name);
    +LIBBPF_API struct bpf_link *
    +bpf_program__attach_subsys(const struct bpf_program *prog,
    + const char *subsys_name);

    struct bpf_map;

    diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
    index dd35ee58bfaa..5583a2dbfb7c 100644
    --- a/tools/lib/bpf/libbpf.map
    +++ b/tools/lib/bpf/libbpf.map
    @@ -447,4 +447,5 @@ LIBBPF_0.8.0 {
    libbpf_register_prog_handler;
    libbpf_unregister_prog_handler;
    bpf_program__attach_kprobe_multi_opts;
    + bpf_program__attach_subsys;
    } LIBBPF_0.7.0;
    --
    2.36.0.512.ge40c2bad7a-goog
    \
     
     \ /
      Last update: 2022-05-10 02:19    [W:5.035 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site