libbpf: Add generic bpf_program__attach()
Generalize BPF program attaching and allow libbpf to auto-detect type (and extra parameters, where applicable) and attach supported BPF program types based on program sections. Currently this is supported for: - kprobe/kretprobe; - tracepoint; - raw tracepoint; - tracing programs (typed raw TP/fentry/fexit). More types support can be trivially added within this framework. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20191214014341.3442258-3-andriin@fb.com
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
Родитель
0d13bfce02
Коммит
d7a18ea7e8
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@ -4972,7 +4972,28 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
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*/
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#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
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static const struct {
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#define SEC_DEF(sec_pfx, ptype, ...) { \
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.sec = sec_pfx, \
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.len = sizeof(sec_pfx) - 1, \
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.prog_type = BPF_PROG_TYPE_##ptype, \
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__VA_ARGS__ \
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}
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struct bpf_sec_def;
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typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
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struct bpf_program *prog);
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static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
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struct bpf_program *prog);
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static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
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struct bpf_program *prog);
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static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
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struct bpf_program *prog);
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static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
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struct bpf_program *prog);
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struct bpf_sec_def {
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const char *sec;
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size_t len;
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enum bpf_prog_type prog_type;
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@ -4980,25 +5001,40 @@ static const struct {
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bool is_attachable;
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bool is_attach_btf;
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enum bpf_attach_type attach_type;
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} section_names[] = {
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attach_fn_t attach_fn;
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};
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static const struct bpf_sec_def section_defs[] = {
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BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
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BPF_PROG_SEC("sk_reuseport", BPF_PROG_TYPE_SK_REUSEPORT),
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BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
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SEC_DEF("kprobe/", KPROBE,
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.attach_fn = attach_kprobe),
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BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE),
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BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
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SEC_DEF("kretprobe/", KPROBE,
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.attach_fn = attach_kprobe),
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BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE),
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BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
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BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
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BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
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BPF_PROG_SEC("tp/", BPF_PROG_TYPE_TRACEPOINT),
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BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
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BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
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BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
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BPF_TRACE_RAW_TP),
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BPF_PROG_BTF("fentry/", BPF_PROG_TYPE_TRACING,
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BPF_TRACE_FENTRY),
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BPF_PROG_BTF("fexit/", BPF_PROG_TYPE_TRACING,
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BPF_TRACE_FEXIT),
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SEC_DEF("tracepoint/", TRACEPOINT,
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.attach_fn = attach_tp),
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SEC_DEF("tp/", TRACEPOINT,
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.attach_fn = attach_tp),
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SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
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.attach_fn = attach_raw_tp),
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SEC_DEF("raw_tp/", RAW_TRACEPOINT,
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.attach_fn = attach_raw_tp),
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SEC_DEF("tp_btf/", TRACING,
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.expected_attach_type = BPF_TRACE_RAW_TP,
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.is_attach_btf = true,
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.attach_fn = attach_trace),
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SEC_DEF("fentry/", TRACING,
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.expected_attach_type = BPF_TRACE_FENTRY,
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.is_attach_btf = true,
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.attach_fn = attach_trace),
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SEC_DEF("fexit/", TRACING,
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.expected_attach_type = BPF_TRACE_FEXIT,
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.is_attach_btf = true,
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.attach_fn = attach_trace),
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BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
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BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
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BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
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@ -5060,12 +5096,26 @@ static const struct {
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#undef BPF_APROG_SEC
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#undef BPF_EAPROG_SEC
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#undef BPF_APROG_COMPAT
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#undef SEC_DEF
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#define MAX_TYPE_NAME_SIZE 32
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static const struct bpf_sec_def *find_sec_def(const char *sec_name)
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{
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int i, n = ARRAY_SIZE(section_defs);
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for (i = 0; i < n; i++) {
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if (strncmp(sec_name,
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section_defs[i].sec, section_defs[i].len))
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continue;
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return §ion_defs[i];
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}
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return NULL;
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}
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static char *libbpf_get_type_names(bool attach_type)
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{
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int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;
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int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
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char *buf;
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buf = malloc(len);
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@ -5074,16 +5124,16 @@ static char *libbpf_get_type_names(bool attach_type)
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buf[0] = '\0';
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/* Forge string buf with all available names */
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for (i = 0; i < ARRAY_SIZE(section_names); i++) {
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if (attach_type && !section_names[i].is_attachable)
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for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
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if (attach_type && !section_defs[i].is_attachable)
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continue;
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if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {
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if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
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free(buf);
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return NULL;
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}
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strcat(buf, " ");
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strcat(buf, section_names[i].sec);
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strcat(buf, section_defs[i].sec);
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}
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return buf;
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@ -5092,19 +5142,19 @@ static char *libbpf_get_type_names(bool attach_type)
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int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
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enum bpf_attach_type *expected_attach_type)
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{
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const struct bpf_sec_def *sec_def;
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char *type_names;
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int i;
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if (!name)
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return -EINVAL;
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for (i = 0; i < ARRAY_SIZE(section_names); i++) {
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if (strncmp(name, section_names[i].sec, section_names[i].len))
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continue;
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*prog_type = section_names[i].prog_type;
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*expected_attach_type = section_names[i].expected_attach_type;
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sec_def = find_sec_def(name);
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if (sec_def) {
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*prog_type = sec_def->prog_type;
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*expected_attach_type = sec_def->expected_attach_type;
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return 0;
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}
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pr_warn("failed to guess program type from ELF section '%s'\n", name);
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type_names = libbpf_get_type_names(false);
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if (type_names != NULL) {
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@ -5187,16 +5237,16 @@ static int libbpf_find_attach_btf_id(const char *name,
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if (!name)
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return -EINVAL;
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for (i = 0; i < ARRAY_SIZE(section_names); i++) {
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if (!section_names[i].is_attach_btf)
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for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
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if (!section_defs[i].is_attach_btf)
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continue;
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if (strncmp(name, section_names[i].sec, section_names[i].len))
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if (strncmp(name, section_defs[i].sec, section_defs[i].len))
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continue;
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if (attach_prog_fd)
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err = libbpf_find_prog_btf_id(name + section_names[i].len,
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err = libbpf_find_prog_btf_id(name + section_defs[i].len,
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attach_prog_fd);
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else
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err = libbpf_find_vmlinux_btf_id(name + section_names[i].len,
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err = libbpf_find_vmlinux_btf_id(name + section_defs[i].len,
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attach_type);
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if (err <= 0)
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pr_warn("%s is not found in vmlinux BTF\n", name);
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@ -5215,12 +5265,12 @@ int libbpf_attach_type_by_name(const char *name,
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if (!name)
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return -EINVAL;
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for (i = 0; i < ARRAY_SIZE(section_names); i++) {
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if (strncmp(name, section_names[i].sec, section_names[i].len))
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for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
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if (strncmp(name, section_defs[i].sec, section_defs[i].len))
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continue;
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if (!section_names[i].is_attachable)
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if (!section_defs[i].is_attachable)
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return -EINVAL;
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*attach_type = section_names[i].attach_type;
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*attach_type = section_defs[i].attach_type;
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return 0;
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}
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pr_warn("failed to guess attach type based on ELF section name '%s'\n", name);
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@ -5680,6 +5730,18 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
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return link;
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}
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static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
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struct bpf_program *prog)
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{
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const char *func_name;
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bool retprobe;
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func_name = bpf_program__title(prog, false) + sec->len;
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retprobe = strcmp(sec->sec, "kretprobe/") == 0;
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return bpf_program__attach_kprobe(prog, retprobe, func_name);
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}
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struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
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bool retprobe, pid_t pid,
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const char *binary_path,
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@ -5792,6 +5854,32 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
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return link;
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}
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static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
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struct bpf_program *prog)
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{
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char *sec_name, *tp_cat, *tp_name;
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struct bpf_link *link;
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sec_name = strdup(bpf_program__title(prog, false));
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if (!sec_name)
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return ERR_PTR(-ENOMEM);
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/* extract "tp/<category>/<name>" */
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tp_cat = sec_name + sec->len;
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tp_name = strchr(tp_cat, '/');
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if (!tp_name) {
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link = ERR_PTR(-EINVAL);
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goto out;
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}
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*tp_name = '\0';
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tp_name++;
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link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
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out:
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free(sec_name);
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return link;
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}
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static int bpf_link__destroy_fd(struct bpf_link *link)
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{
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struct bpf_link_fd *l = (void *)link;
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@ -5831,6 +5919,14 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
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return (struct bpf_link *)link;
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}
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static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
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struct bpf_program *prog)
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{
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const char *tp_name = bpf_program__title(prog, false) + sec->len;
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return bpf_program__attach_raw_tracepoint(prog, tp_name);
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}
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struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
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{
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char errmsg[STRERR_BUFSIZE];
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@ -5862,6 +5958,23 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
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return (struct bpf_link *)link;
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}
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static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
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struct bpf_program *prog)
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{
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return bpf_program__attach_trace(prog);
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}
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struct bpf_link *bpf_program__attach(struct bpf_program *prog)
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{
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const struct bpf_sec_def *sec_def;
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sec_def = find_sec_def(bpf_program__title(prog, false));
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if (!sec_def || !sec_def->attach_fn)
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return ERR_PTR(-ESRCH);
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return sec_def->attach_fn(sec_def, prog);
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}
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enum bpf_perf_event_ret
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bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
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void **copy_mem, size_t *copy_size,
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@ -237,6 +237,8 @@ struct bpf_link;
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LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
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LIBBPF_API struct bpf_link *
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bpf_program__attach(struct bpf_program *prog);
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LIBBPF_API struct bpf_link *
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bpf_program__attach_perf_event(struct bpf_program *prog, int pfd);
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LIBBPF_API struct bpf_link *
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@ -210,4 +210,6 @@ LIBBPF_0.0.6 {
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} LIBBPF_0.0.5;
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LIBBPF_0.0.7 {
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global:
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bpf_program__attach;
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} LIBBPF_0.0.6;
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@ -3,8 +3,7 @@
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void test_probe_user(void)
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{
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#define kprobe_name "__sys_connect"
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const char *prog_name = "kprobe/" kprobe_name;
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const char *prog_name = "kprobe/__sys_connect";
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const char *obj_file = "./test_probe_user.o";
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DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, );
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int err, results_map_fd, sock_fd, duration = 0;
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@ -33,8 +32,7 @@ void test_probe_user(void)
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"err %d\n", results_map_fd))
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goto cleanup;
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kprobe_link = bpf_program__attach_kprobe(kprobe_prog, false,
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kprobe_name);
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kprobe_link = bpf_program__attach(kprobe_prog);
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if (CHECK(IS_ERR(kprobe_link), "attach_kprobe",
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"err %ld\n", PTR_ERR(kprobe_link))) {
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kprobe_link = NULL;
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