On Tue, Apr 23, 2024 at 05:26:59PM -0700, Andrii Nakryiko wrote:
SNIP
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 97eb6e5dd7c8..ca605240205f 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -9272,6 +9272,7 @@ static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_lin
> > static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > +static int attach_kprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
> > @@ -9288,6 +9289,7 @@ static const struct bpf_sec_def section_defs[] = {
> > SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
> > SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
> > SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
> > + SEC_DEF("kprobe.session+", KPROBE, BPF_TRACE_KPROBE_MULTI_SESSION, SEC_NONE, attach_kprobe_session),
> > SEC_DEF("uprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> > SEC_DEF("uretprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> > SEC_DEF("uprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
> > @@ -11380,13 +11382,14 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> > struct kprobe_multi_resolve res = {
> > .pattern = pattern,
> > };
> > + enum bpf_attach_type attach_type;
> > struct bpf_link *link = NULL;
> > char errmsg[STRERR_BUFSIZE];
> > const unsigned long *addrs;
> > int err, link_fd, prog_fd;
> > + bool retprobe, session;
> > const __u64 *cookies;
> > const char **syms;
> > - bool retprobe;
> > size_t cnt;
> >
> > if (!OPTS_VALID(opts, bpf_kprobe_multi_opts))
> > @@ -11425,6 +11428,13 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> > }
> >
> > retprobe = OPTS_GET(opts, retprobe, false);
> > + session = OPTS_GET(opts, session, false);
> > +
> > + if (retprobe && session)
> > + return libbpf_err_ptr(-EINVAL);
> > +
> > + attach_type = session ? BPF_TRACE_KPROBE_MULTI_SESSION :
> > + BPF_TRACE_KPROBE_MULTI;
>
> doesn't fit under 100?
88 ;-) ok
>
> >
> > lopts.kprobe_multi.syms = syms;
> > lopts.kprobe_multi.addrs = addrs;
> > @@ -11439,7 +11449,7 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> > }
> > link->detach = &bpf_link__detach_fd;
> >
> > - link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, &lopts);
> > + link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
> > if (link_fd < 0) {
> > err = -errno;
> > pr_warn("prog '%s': failed to attach: %s\n",
> > @@ -11545,6 +11555,32 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru
> > return libbpf_get_error(*link);
> > }
> >
> > +static int attach_kprobe_session(const struct bpf_program *prog, long cookie,
> > + struct bpf_link **link)
> > +{
> > + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts, .session = true);
> > + const char *spec;
> > + char *pattern;
> > + int n;
> > +
> > + *link = NULL;
> > +
> > + /* no auto-attach for SEC("kprobe.session") */
> > + if (strcmp(prog->sec_name, "kprobe.session") == 0)
> > + return 0;
> > +
> > + spec = prog->sec_name + sizeof("kprobe.session/") - 1;
> > + n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
> > + if (n < 1) {
> > + pr_warn("kprobe session pattern is invalid: %s\n", pattern);
> > + return -EINVAL;
> > + }
> > +
> > + *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts);
> > + free(pattern);
> > + return libbpf_get_error(*link);
>
> let's try not to add new uses of libbpf_get_error? Would this work:
>
> return *link ? 0 : -errno;
ok
jirka
