[PATCHv2 bpf-next 12/24] libbpf: Add support for u[ret]probe.multi[.s] program sections

Jiri Olsa
2023-06-20T08:37:52Z

Adding support for several uprobe_multi program sections
to allow auto attach of multi_uprobe programs.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d972cea4c658..e42080258ec7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8652,6 +8652,7 @@ 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_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);

@@ -8667,6 +8668,10 @@ 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("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),
+ SEC_DEF("uretprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
SEC_DEF("usdt+", KPROBE, 0, SEC_NONE, attach_usdt),
@@ -10728,6 +10733,41 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru
return libbpf_get_error(*link);
}

+static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+ char *probe_type = NULL, *binary_path = NULL, *func_name = NULL;
+ LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
+ int n, ret = -EINVAL;
+
+ *link = NULL;
+
+ n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%ms",
+ &probe_type, &binary_path, &func_name);
+ switch (n) {
+ case 1:
+ /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */
+ ret = 0;
+ break;
+ case 2:
+ pr_warn("prog '%s': section '%s' missing ':function[+offset]' specification\n",
+ prog->name, prog->sec_name);
+ break;
+ case 3:
+ opts.retprobe = strcmp(probe_type, "uretprobe.multi");
+ *link = bpf_program__attach_uprobe_multi_opts(prog, -1, binary_path, func_name, &opts);
+ ret = libbpf_get_error(*link);
+ break;
+ default:
+ pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name,
+ prog->sec_name);
+ break;
+ }
+ free(probe_type);
+ free(binary_path);
+ free(func_name);
+ return ret;
+}
+
static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz,
const char *binary_path, uint64_t offset)
{
--
2.41.0