Adding bpf_program__attach_tracing_multi function for attaching
tracing program to multiple functions.
struct bpf_link *
bpf_program__attach_tracing_multi(const struct bpf_program *prog,
const char *pattern,
const struct bpf_tracing_multi_opts *opts);
User can specify functions to attach with 'pattern' argument that
allows wildcards (*?' supported) or provide BTF ids of functions
in array directly via opts argument. These options are mutually
exclusive.
When using BTF ids, user can also provide cookie value for each
provided id/function, that can be retrieved later in bpf program
with bpf_get_attach_cookie helper. Each cookie value is paired with
provided BTF id with the same array index.
Adding support to auto attach programs with following sections:
fsession.multi/<pattern>
fsession.multi.s/<pattern>
fentry.multi/<pattern>
fexit.multi/<pattern>
fentry.multi.s/<pattern>
fexit.multi.s/<pattern>
The provided <pattern> is used as 'pattern' argument in
bpf_program__attach_kprobe_multi_opts function.
Signed-off-by: Jiri Olsa <[email protected]>
---
tools/lib/bpf/bpf.c | 9 ++
tools/lib/bpf/bpf.h | 5 +
tools/lib/bpf/libbpf.c | 196 +++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 15 +++
tools/lib/bpf/libbpf.map | 1 +
5 files changed, 226 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 5846de364209..6c741df4c311 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -790,6 +790,15 @@ int bpf_link_create(int prog_fd, int target_fd,
if (!OPTS_ZEROED(opts, uprobe_multi))
return libbpf_err(-EINVAL);
break;
+ case BPF_TRACE_FENTRY_MULTI:
+ case BPF_TRACE_FEXIT_MULTI:
+ case BPF_TRACE_FSESSION_MULTI:
+ attr.link_create.tracing_multi.ids = (__u64) OPTS_GET(opts,
tracing_multi.ids, 0);
+ attr.link_create.tracing_multi.cookies = (__u64) OPTS_GET(opts,
tracing_multi.cookies, 0);
+ attr.link_create.tracing_multi.cnt = OPTS_GET(opts,
tracing_multi.cnt, 0);
+ if (!OPTS_ZEROED(opts, tracing_multi))
+ return libbpf_err(-EINVAL);
+ break;
case BPF_TRACE_RAW_TP:
case BPF_TRACE_FENTRY:
case BPF_TRACE_FEXIT:
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 2c8e88ddb674..726a6fa585b3 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -454,6 +454,11 @@ struct bpf_link_create_opts {
__u32 relative_id;
__u64 expected_revision;
} cgroup;
+ struct {
+ __u32 *ids;
+ __u64 *cookies;
+ __u32 cnt;
+ } tracing_multi;
};
size_t :0;
};
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1eb3869e3444..82eca31a8cc2 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9827,6 +9827,7 @@ static int attach_kprobe_session(const struct bpf_program
*prog, long cookie, st
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);
+static int attach_tracing_multi(const struct bpf_program *prog, long cookie,
struct bpf_link **link);
static const struct bpf_sec_def section_defs[] = {
SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE),
@@ -9875,6 +9876,12 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT,
SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
SEC_DEF("fsession+", TRACING, BPF_TRACE_FSESSION,
SEC_ATTACH_BTF, attach_trace),
SEC_DEF("fsession.s+", TRACING, BPF_TRACE_FSESSION,
SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+ SEC_DEF("fsession.multi+", TRACING, BPF_TRACE_FSESSION_MULTI, 0,
attach_tracing_multi),
+ SEC_DEF("fsession.multi.s+", TRACING, BPF_TRACE_FSESSION_MULTI,
SEC_SLEEPABLE, attach_tracing_multi),
+ SEC_DEF("fentry.multi+", TRACING, BPF_TRACE_FENTRY_MULTI, 0,
attach_tracing_multi),
+ SEC_DEF("fexit.multi+", TRACING, BPF_TRACE_FEXIT_MULTI, 0,
attach_tracing_multi),
+ SEC_DEF("fentry.multi.s+", TRACING, BPF_TRACE_FENTRY_MULTI,
SEC_SLEEPABLE, attach_tracing_multi),
+ SEC_DEF("fexit.multi.s+", TRACING, BPF_TRACE_FEXIT_MULTI,
SEC_SLEEPABLE, attach_tracing_multi),
SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace),
SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF,
attach_lsm),
SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF |
SEC_SLEEPABLE, attach_lsm),
@@ -12250,6 +12257,195 @@ static int attach_uprobe_multi(const struct
bpf_program *prog, long cookie, stru
return ret;
}
+#define MAX_BPF_FUNC_ARGS 12
+
+static bool btf_type_is_modifier(const struct btf_type *t)
+{
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_TYPEDEF:
+ case BTF_KIND_VOLATILE:
+ case BTF_KIND_CONST:
+ case BTF_KIND_RESTRICT:
+ case BTF_KIND_TYPE_TAG:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool is_allowed_func(const struct btf *btf, const struct btf_type *t)
+{
+ const struct btf_type *proto;
+ const struct btf_param *args;
+ __u32 i, nargs;
+ __s64 ret;
+
+ proto = btf_type_by_id(btf, t->type);
+ if (BTF_INFO_KIND(proto->info) != BTF_KIND_FUNC_PROTO)
+ return false;
+
+ args = (const struct btf_param *)(proto + 1);
+ nargs = btf_vlen(proto);
+ if (nargs > MAX_BPF_FUNC_ARGS)
+ return false;
+
+ /* No support for struct/union return argument type. */
+ t = btf__type_by_id(btf, proto->type);
+ while (t && btf_type_is_modifier(t))
+ t = btf__type_by_id(btf, t->type);
+
+ if (btf_is_struct(t) || btf_is_union(t))
+ return false;
+
+ for (i = 0; i < nargs; i++) {
+ /* No support for variable args. */
+ if (i == nargs - 1 && args[i].type == 0)
+ return false;
+
+ /* No support of struct argument size greater than 16 bytes. */
+ ret = btf__resolve_size(btf, args[i].type);
+ if (ret < 0 || ret > 16)
+ return false;
+ }
+
+ return true;
+}
+
+static int
+collect_btf_func_ids_by_glob(const struct btf *btf, const char *pattern, __u32
**ids)
+{
+ __u32 type_id, nr_types = btf__type_cnt(btf);
+ size_t cap = 0, cnt = 0;
+
+ if (!pattern)
+ return -EINVAL;
+
+ for (type_id = 1; type_id < nr_types; type_id++) {
+ const struct btf_type *t = btf__type_by_id(btf, type_id);
+ const char *name;
+ int err;
+
+ if (btf_kind(t) != BTF_KIND_FUNC)
+ continue;
+ name = btf__name_by_offset(btf, t->name_off);
+ if (!name)
+ continue;
+
+ if (!glob_match(name, pattern))
+ continue;
+ if (!is_allowed_func(btf, t))
+ continue;
+
+ err = libbpf_ensure_mem((void **) ids, &cap, sizeof(**ids), cnt
+ 1);
+ if (err) {
+ free(*ids);
+ return -ENOMEM;
+ }
+ (*ids)[cnt++] = type_id;
+ }
+
+ return cnt;
+}
+
+struct bpf_link *
+bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char
*pattern,
+ const struct bpf_tracing_multi_opts *opts)
+{
+ LIBBPF_OPTS(bpf_link_create_opts, lopts);
+ __u32 *ids, cnt, *free_ids = NULL;
+ __u64 *cookies;
+ int prog_fd, link_fd, err;
+ struct bpf_link *link;
+
+ ids = OPTS_GET(opts, ids, NULL);
+ cookies = OPTS_GET(opts, cookies, NULL);
+ cnt = OPTS_GET(opts, cnt, 0);
+
+ if (!!ids != !!cnt)
+ return libbpf_err_ptr(-EINVAL);
+ if (pattern && (ids || cookies))
+ return libbpf_err_ptr(-EINVAL);
+ if (!pattern && !ids)
+ return libbpf_err_ptr(-EINVAL);
+
+ if (pattern) {
+ err = bpf_object__load_vmlinux_btf(prog->obj, true);
+ if (err)
+ return libbpf_err_ptr(err);
+
+ cnt = collect_btf_func_ids_by_glob(prog->obj->btf_vmlinux,
pattern, &ids);
+ if (cnt < 0)
+ return libbpf_err_ptr(cnt);
+ if (cnt == 0)
+ return libbpf_err_ptr(-EINVAL);
+ free_ids = ids;
+ }
+
+ lopts.tracing_multi.ids = ids;
+ lopts.tracing_multi.cookies = cookies;
+ lopts.tracing_multi.cnt = cnt;
+
+ link = calloc(1, sizeof(*link));
+ if (!link) {
+ err = -ENOMEM;
+ goto error;
+ }
+ link->detach = &bpf_link__detach_fd;
+
+ prog_fd = bpf_program__fd(prog);
+ link_fd = bpf_link_create(prog_fd, 0, prog->expected_attach_type,
&lopts);
+ if (link_fd < 0) {
+ err = -errno;
+ pr_warn("prog '%s': failed to attach: %s\n", prog->name,
errstr(err));
+ goto error;
+ }
+ link->fd = link_fd;
+ free(free_ids);
+ return link;
+
+error:
+ free(link);
+ free(free_ids);
+ return libbpf_err_ptr(err);
+}
+
+static int attach_tracing_multi(const struct bpf_program *prog, long cookie,
struct bpf_link **link)
+{
+ bool is_fexit, is_fsession;
+ const char *spec;
+ char *pattern;
+ int n;
+
+ /* Do not allow auto attach if there's no function pattern. */
+ if (strcmp(prog->sec_name, "fentry.multi") == 0 ||
+ strcmp(prog->sec_name, "fexit.multi") == 0 ||
+ strcmp(prog->sec_name, "fsession.multi") == 0 ||
+ strcmp(prog->sec_name, "fentry.multi.s") == 0 ||
+ strcmp(prog->sec_name, "fexit.multi.s") == 0 ||
+ strcmp(prog->sec_name, "fsession.multi.s") == 0)
+ return 0;
+
+ is_fexit = str_has_pfx(prog->sec_name, "fexit.multi/");
+ is_fsession = str_has_pfx(prog->sec_name, "fsession.multi/");
+
+ if (is_fsession)
+ spec = prog->sec_name + sizeof("fsession.multi/") - 1;
+ else if (is_fexit)
+ spec = prog->sec_name + sizeof("fexit.multi/") - 1;
+ else
+ spec = prog->sec_name + sizeof("fentry.multi/") - 1;
+
+ n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
+ if (n < 1) {
+ pr_warn("tracing multi pattern is invalid: %s\n", spec);
+ return -EINVAL;
+ }
+
+ *link = bpf_program__attach_tracing_multi(prog, pattern, NULL);
+ free(pattern);
+ return libbpf_get_error(*link);
+}
+
static inline int add_uprobe_event_legacy(const char *probe_name, bool
retprobe,
const char *binary_path, size_t
offset)
{
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index dfc37a615578..b677aea7e592 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -701,6 +701,21 @@ bpf_program__attach_ksyscall(const struct bpf_program
*prog,
const char *syscall_name,
const struct bpf_ksyscall_opts *opts);
+struct bpf_tracing_multi_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+ __u32 *ids;
+ __u64 *cookies;
+ size_t cnt;
+ size_t :0;
+};
+
+#define bpf_tracing_multi_opts__last_field cnt
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char
*pattern,
+ const struct bpf_tracing_multi_opts *opts);
+
struct bpf_uprobe_opts {
/* size of this struct, for forward/backward compatibility */
size_t sz;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index d18fbcea7578..ff4d7b2c8a14 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -452,6 +452,7 @@ LIBBPF_1.7.0 {
bpf_map__set_exclusive_program;
bpf_map__exclusive_program;
bpf_prog_assoc_struct_ops;
+ bpf_program__attach_tracing_multi;
bpf_program__assoc_struct_ops;
btf__permute;
} LIBBPF_1.6.0;
--
2.52.0
