mirror/libbpf
1
0
Fork 0
mirror of https://github.com/netdata/libbpf.git synced 2026-04-01 22:29:06 +08:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: Add bpf_cookie to perf_event, kprobe, uprobe, and tp attach APIs

Browse Source 
Wire through bpf_cookie for all attach APIs that use perf_event_open under the
hood:
  - for kprobes, extend existing bpf_kprobe_opts with bpf_cookie field;
  - for perf_event, uprobe, and tracepoint APIs, add their _opts variants and
    pass bpf_cookie through opts.

For kernel that don't support BPF_LINK_CREATE for perf_events, and thus
bpf_cookie is not supported either, return error and log warning for user.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210815070609.987780-12-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
2021-08-15 00:06:04 -07:00
committed by Andrii Nakryiko
parent a3f8c5a306
commit 91259bc676
3 changed files with 127 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

78
src/libbpf.c
View File

@@ -9014,12 +9014,16 @@ static void bpf_link_perf_dealloc(struct bpf_link *link)
free(perf_link);
}
struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pfd)
struct bpf_link *bpf_program__attach_perf_event_opts(struct bpf_program *prog, int pfd,
const struct bpf_perf_event_opts *opts)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_perf *link;
int prog_fd, link_fd = -1, err;
if (!OPTS_VALID(opts, bpf_perf_event_opts))
return libbpf_err_ptr(-EINVAL);
if (pfd < 0) {
pr_warn("prog '%s': invalid perf event FD %d\n",
prog->name, pfd);
@@ -9040,7 +9044,10 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pf
link->perf_event_fd = pfd;
if (kernel_supports(prog->obj, FEAT_PERF_LINK)) {
link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, NULL);
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts,
.perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0));
link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, &link_opts);
if (link_fd < 0) {
err = -errno;
pr_warn("prog '%s': failed to create BPF link for perf_event FD %d: %d (%s)\n",
@@ -9050,6 +9057,12 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pf
}
link->link.fd = link_fd;
} else {
if (OPTS_GET(opts, bpf_cookie, 0)) {
pr_warn("prog '%s': user context value is not supported\n", prog->name);
err = -EOPNOTSUPP;
goto err_out;
}
if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
err = -errno;
pr_warn("prog '%s': failed to attach to perf_event FD %d: %s\n",
@@ -9076,6 +9089,11 @@ err_out:
return libbpf_err_ptr(err);
}
struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pfd)
{
return bpf_program__attach_perf_event_opts(prog, pfd, NULL);
}
/*
* this function is expected to parse integer in the range of [0, 2^31-1] from
* given file using scanf format string fmt. If actual parsed value is
@@ -9184,8 +9202,9 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
struct bpf_link *
bpf_program__attach_kprobe_opts(struct bpf_program *prog,
const char *func_name,
struct bpf_kprobe_opts *opts)
const struct bpf_kprobe_opts *opts)
{
DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
unsigned long offset;
@@ -9197,6 +9216,7 @@ bpf_program__attach_kprobe_opts(struct bpf_program *prog,
retprobe = OPTS_GET(opts, retprobe, false);
offset = OPTS_GET(opts, offset, 0);
pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
offset, -1 /* pid */);
@@ -9206,7 +9226,7 @@ bpf_program__attach_kprobe_opts(struct bpf_program *prog,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return libbpf_err_ptr(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
err = libbpf_get_error(link);
if (err) {
close(pfd);
@@ -9261,14 +9281,22 @@ static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
return link;
}
struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
bool retprobe, pid_t pid,
const char *binary_path,
size_t func_offset)
LIBBPF_API struct bpf_link *
bpf_program__attach_uprobe_opts(struct bpf_program *prog, pid_t pid,
const char *binary_path, size_t func_offset,
const struct bpf_uprobe_opts *opts)
{
DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
bool retprobe;
if (!OPTS_VALID(opts, bpf_uprobe_opts))
return libbpf_err_ptr(-EINVAL);
retprobe = OPTS_GET(opts, retprobe, false);
pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
pfd = perf_event_open_probe(true /* uprobe */, retprobe,
binary_path, func_offset, pid);
@@ -9279,7 +9307,7 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return libbpf_err_ptr(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
err = libbpf_get_error(link);
if (err) {
close(pfd);
@@ -9292,6 +9320,16 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
return link;
}
struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
bool retprobe, pid_t pid,
const char *binary_path,
size_t func_offset)
{
DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts, .retprobe = retprobe);
return bpf_program__attach_uprobe_opts(prog, pid, binary_path, func_offset, &opts);
}
static int determine_tracepoint_id(const char *tp_category,
const char *tp_name)
{
@@ -9342,14 +9380,21 @@ static int perf_event_open_tracepoint(const char *tp_category,
return pfd;
}
struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name)
struct bpf_link *bpf_program__attach_tracepoint_opts(struct bpf_program *prog,
const char *tp_category,
const char *tp_name,
const struct bpf_tracepoint_opts *opts)
{
DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
if (!OPTS_VALID(opts, bpf_tracepoint_opts))
return libbpf_err_ptr(-EINVAL);
pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
pfd = perf_event_open_tracepoint(tp_category, tp_name);
if (pfd < 0) {
pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
@@ -9357,7 +9402,7 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return libbpf_err_ptr(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
err = libbpf_get_error(link);
if (err) {
close(pfd);
@@ -9369,6 +9414,13 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
return link;
}
struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name)
{
return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);
}
static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog)
{