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-rw-r--r--include/linux/bpf.h13
-rw-r--r--kernel/bpf/inode.c42
-rw-r--r--kernel/bpf/syscall.c223
-rw-r--r--tools/lib/bpf/libbpf.c131
-rw-r--r--tools/lib/bpf/libbpf.h5
-rw-r--r--tools/lib/bpf/libbpf.map5
-rw-r--r--tools/testing/selftests/bpf/prog_tests/link_pinning.c105
-rw-r--r--tools/testing/selftests/bpf/progs/test_link_pinning.c25
8 files changed, 476 insertions, 73 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 6015a4daf118..f13c78c6f29d 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1056,6 +1056,19 @@ extern int sysctl_unprivileged_bpf_disabled;
int bpf_map_new_fd(struct bpf_map *map, int flags);
int bpf_prog_new_fd(struct bpf_prog *prog);
+struct bpf_link;
+
+struct bpf_link_ops {
+ void (*release)(struct bpf_link *link);
+};
+
+void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops,
+ struct bpf_prog *prog);
+void bpf_link_inc(struct bpf_link *link);
+void bpf_link_put(struct bpf_link *link);
+int bpf_link_new_fd(struct bpf_link *link);
+struct bpf_link *bpf_link_get_from_fd(u32 ufd);
+
int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
int bpf_obj_get_user(const char __user *pathname, int flags);
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 5e40e7fccc21..95087d9f4ed3 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -25,6 +25,7 @@ enum bpf_type {
BPF_TYPE_UNSPEC = 0,
BPF_TYPE_PROG,
BPF_TYPE_MAP,
+ BPF_TYPE_LINK,
};
static void *bpf_any_get(void *raw, enum bpf_type type)
@@ -36,6 +37,9 @@ static void *bpf_any_get(void *raw, enum bpf_type type)
case BPF_TYPE_MAP:
bpf_map_inc_with_uref(raw);
break;
+ case BPF_TYPE_LINK:
+ bpf_link_inc(raw);
+ break;
default:
WARN_ON_ONCE(1);
break;
@@ -53,6 +57,9 @@ static void bpf_any_put(void *raw, enum bpf_type type)
case BPF_TYPE_MAP:
bpf_map_put_with_uref(raw);
break;
+ case BPF_TYPE_LINK:
+ bpf_link_put(raw);
+ break;
default:
WARN_ON_ONCE(1);
break;
@@ -63,20 +70,32 @@ static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
{
void *raw;
- *type = BPF_TYPE_MAP;
raw = bpf_map_get_with_uref(ufd);
- if (IS_ERR(raw)) {
+ if (!IS_ERR(raw)) {
+ *type = BPF_TYPE_MAP;
+ return raw;
+ }
+
+ raw = bpf_prog_get(ufd);
+ if (!IS_ERR(raw)) {
*type = BPF_TYPE_PROG;
- raw = bpf_prog_get(ufd);
+ return raw;
}
- return raw;
+ raw = bpf_link_get_from_fd(ufd);
+ if (!IS_ERR(raw)) {
+ *type = BPF_TYPE_LINK;
+ return raw;
+ }
+
+ return ERR_PTR(-EINVAL);
}
static const struct inode_operations bpf_dir_iops;
static const struct inode_operations bpf_prog_iops = { };
static const struct inode_operations bpf_map_iops = { };
+static const struct inode_operations bpf_link_iops = { };
static struct inode *bpf_get_inode(struct super_block *sb,
const struct inode *dir,
@@ -114,6 +133,8 @@ static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
*type = BPF_TYPE_PROG;
else if (inode->i_op == &bpf_map_iops)
*type = BPF_TYPE_MAP;
+ else if (inode->i_op == &bpf_link_iops)
+ *type = BPF_TYPE_LINK;
else
return -EACCES;
@@ -335,6 +356,12 @@ static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg)
&bpffs_map_fops : &bpffs_obj_fops);
}
+static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg)
+{
+ return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops,
+ &bpffs_obj_fops);
+}
+
static struct dentry *
bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
{
@@ -411,6 +438,9 @@ static int bpf_obj_do_pin(const char __user *pathname, void *raw,
case BPF_TYPE_MAP:
ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw);
break;
+ case BPF_TYPE_LINK:
+ ret = vfs_mkobj(dentry, mode, bpf_mklink, raw);
+ break;
default:
ret = -EPERM;
}
@@ -487,6 +517,8 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
ret = bpf_prog_new_fd(raw);
else if (type == BPF_TYPE_MAP)
ret = bpf_map_new_fd(raw, f_flags);
+ else if (type == BPF_TYPE_LINK)
+ ret = bpf_link_new_fd(raw);
else
return -ENOENT;
@@ -504,6 +536,8 @@ static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type
if (inode->i_op == &bpf_map_iops)
return ERR_PTR(-EINVAL);
+ if (inode->i_op == &bpf_link_iops)
+ return ERR_PTR(-EINVAL);
if (inode->i_op != &bpf_prog_iops)
return ERR_PTR(-EACCES);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c536c65256ad..13de65363ba2 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2173,24 +2173,154 @@ static int bpf_obj_get(const union bpf_attr *attr)
attr->file_flags);
}
-static int bpf_tracing_prog_release(struct inode *inode, struct file *filp)
+struct bpf_link {
+ atomic64_t refcnt;
+ const struct bpf_link_ops *ops;
+ struct bpf_prog *prog;
+ struct work_struct work;
+};
+
+void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops,
+ struct bpf_prog *prog)
{
- struct bpf_prog *prog = filp->private_data;
+ atomic64_set(&link->refcnt, 1);
+ link->ops = ops;
+ link->prog = prog;
+}
+
+void bpf_link_inc(struct bpf_link *link)
+{
+ atomic64_inc(&link->refcnt);
+}
+
+/* bpf_link_free is guaranteed to be called from process context */
+static void bpf_link_free(struct bpf_link *link)
+{
+ struct bpf_prog *prog;
- WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog));
+ /* remember prog locally, because release below will free link memory */
+ prog = link->prog;
+ /* extra clean up and kfree of container link struct */
+ link->ops->release(link);
+ /* no more accesing of link members after this point */
bpf_prog_put(prog);
+}
+
+static void bpf_link_put_deferred(struct work_struct *work)
+{
+ struct bpf_link *link = container_of(work, struct bpf_link, work);
+
+ bpf_link_free(link);
+}
+
+/* bpf_link_put can be called from atomic context, but ensures that resources
+ * are freed from process context
+ */
+void bpf_link_put(struct bpf_link *link)
+{
+ if (!atomic64_dec_and_test(&link->refcnt))
+ return;
+
+ if (in_atomic()) {
+ INIT_WORK(&link->work, bpf_link_put_deferred);
+ schedule_work(&link->work);
+ } else {
+ bpf_link_free(link);
+ }
+}
+
+static int bpf_link_release(struct inode *inode, struct file *filp)
+{
+ struct bpf_link *link = filp->private_data;
+
+ bpf_link_put(link);
return 0;
}
-static const struct file_operations bpf_tracing_prog_fops = {
- .release = bpf_tracing_prog_release,
+#ifdef CONFIG_PROC_FS
+static const struct bpf_link_ops bpf_raw_tp_lops;
+static const struct bpf_link_ops bpf_tracing_link_lops;
+static const struct bpf_link_ops bpf_xdp_link_lops;
+
+static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+ const struct bpf_link *link = filp->private_data;
+ const struct bpf_prog *prog = link->prog;
+ char prog_tag[sizeof(prog->tag) * 2 + 1] = { };
+ const char *link_type;
+
+ if (link->ops == &bpf_raw_tp_lops)
+ link_type = "raw_tracepoint";
+ else if (link->ops == &bpf_tracing_link_lops)
+ link_type = "tracing";
+ else
+ link_type = "unknown";
+
+ bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
+ seq_printf(m,
+ "link_type:\t%s\n"
+ "prog_tag:\t%s\n"
+ "prog_id:\t%u\n",
+ link_type,
+ prog_tag,
+ prog->aux->id);
+}
+#endif
+
+const struct file_operations bpf_link_fops = {
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = bpf_link_show_fdinfo,
+#endif
+ .release = bpf_link_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
+int bpf_link_new_fd(struct bpf_link *link)
+{
+ return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC);
+}
+
+struct bpf_link *bpf_link_get_from_fd(u32 ufd)
+{
+ struct fd f = fdget(ufd);
+ struct bpf_link *link;
+
+ if (!f.file)
+ return ERR_PTR(-EBADF);
+ if (f.file->f_op != &bpf_link_fops) {
+ fdput(f);
+ return ERR_PTR(-EINVAL);
+ }
+
+ link = f.file->private_data;
+ bpf_link_inc(link);
+ fdput(f);
+
+ return link;
+}
+
+struct bpf_tracing_link {
+ struct bpf_link link;
+};
+
+static void bpf_tracing_link_release(struct bpf_link *link)
+{
+ struct bpf_tracing_link *tr_link =
+ container_of(link, struct bpf_tracing_link, link);
+
+ WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog));
+ kfree(tr_link);
+}
+
+static const struct bpf_link_ops bpf_tracing_link_lops = {
+ .release = bpf_tracing_link_release,
+};
+
static int bpf_tracing_prog_attach(struct bpf_prog *prog)
{
- int tr_fd, err;
+ struct bpf_tracing_link *link;
+ int link_fd, err;
if (prog->expected_attach_type != BPF_TRACE_FENTRY &&
prog->expected_attach_type != BPF_TRACE_FEXIT &&
@@ -2199,58 +2329,61 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog)
goto out_put_prog;
}
+ link = kzalloc(sizeof(*link), GFP_USER);
+ if (!link) {
+ err = -ENOMEM;
+ goto out_put_prog;
+ }
+ bpf_link_init(&link->link, &bpf_tracing_link_lops, prog);
+
err = bpf_trampoline_link_prog(prog);
if (err)
- goto out_put_prog;
+ goto out_free_link;
- tr_fd = anon_inode_getfd("bpf-tracing-prog", &bpf_tracing_prog_fops,
- prog, O_CLOEXEC);
- if (tr_fd < 0) {
+ link_fd = bpf_link_new_fd(&link->link);
+ if (link_fd < 0) {
WARN_ON_ONCE(bpf_trampoline_unlink_prog(prog));
- err = tr_fd;
- goto out_put_prog;
+ err = link_fd;
+ goto out_free_link;
}
- return tr_fd;
+ return link_fd;
+out_free_link:
+ kfree(link);
out_put_prog:
bpf_prog_put(prog);
return err;
}
-struct bpf_raw_tracepoint {
+struct bpf_raw_tp_link {
+ struct bpf_link link;
struct bpf_raw_event_map *btp;
- struct bpf_prog *prog;
};
-static int bpf_raw_tracepoint_release(struct inode *inode, struct file *filp)
+static void bpf_raw_tp_link_release(struct bpf_link *link)
{
- struct bpf_raw_tracepoint *raw_tp = filp->private_data;
+ struct bpf_raw_tp_link *raw_tp =
+ container_of(link, struct bpf_raw_tp_link, link);
- if (raw_tp->prog) {
- bpf_probe_unregister(raw_tp->btp, raw_tp->prog);
- bpf_prog_put(raw_tp->prog);
- }
+ bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog);
bpf_put_raw_tracepoint(raw_tp->btp);
kfree(raw_tp);
- return 0;
}
-static const struct file_operations bpf_raw_tp_fops = {
- .release = bpf_raw_tracepoint_release,
- .read = bpf_dummy_read,
- .write = bpf_dummy_write,
+static const struct bpf_link_ops bpf_raw_tp_lops = {
+ .release = bpf_raw_tp_link_release,
};
#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
{
- struct bpf_raw_tracepoint *raw_tp;
+ struct bpf_raw_tp_link *raw_tp;
struct bpf_raw_event_map *btp;
struct bpf_prog *prog;
const char *tp_name;
char buf[128];
- int tp_fd, err;
+ int link_fd, err;
if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
return -EINVAL;
@@ -2302,21 +2435,20 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
err = -ENOMEM;
goto out_put_btp;
}
+ bpf_link_init(&raw_tp->link, &bpf_raw_tp_lops, prog);
raw_tp->btp = btp;
- raw_tp->prog = prog;
err = bpf_probe_register(raw_tp->btp, prog);
if (err)
goto out_free_tp;
- tp_fd = anon_inode_getfd("bpf-raw-tracepoint", &bpf_raw_tp_fops, raw_tp,
- O_CLOEXEC);
- if (tp_fd < 0) {
+ link_fd = bpf_link_new_fd(&raw_tp->link);
+ if (link_fd < 0) {
bpf_probe_unregister(raw_tp->btp, prog);
- err = tp_fd;
+ err = link_fd;
goto out_free_tp;
}
- return tp_fd;
+ return link_fd;
out_free_tp:
kfree(raw_tp);
@@ -3266,15 +3398,21 @@ static int bpf_task_fd_query(const union bpf_attr *attr,
if (err)
goto out;
- if (file->f_op == &bpf_raw_tp_fops) {
- struct bpf_raw_tracepoint *raw_tp = file->private_data;
- struct bpf_raw_event_map *btp = raw_tp->btp;
+ if (file->f_op == &bpf_link_fops) {
+ struct bpf_link *link = file->private_data;
- err = bpf_task_fd_query_copy(attr, uattr,
- raw_tp->prog->aux->id,
- BPF_FD_TYPE_RAW_TRACEPOINT,
- btp->tp->name, 0, 0);
- goto put_file;
+ if (link->ops == &bpf_raw_tp_lops) {
+ struct bpf_raw_tp_link *raw_tp =
+ container_of(link, struct bpf_raw_tp_link, link);
+ struct bpf_raw_event_map *btp = raw_tp->btp;
+
+ err = bpf_task_fd_query_copy(attr, uattr,
+ raw_tp->link.prog->aux->id,
+ BPF_FD_TYPE_RAW_TRACEPOINT,
+ btp->tp->name, 0, 0);
+ goto put_file;
+ }
+ goto out_not_supp;
}
event = perf_get_event(file);
@@ -3294,6 +3432,7 @@ static int bpf_task_fd_query(const union bpf_attr *attr,
goto put_file;
}
+out_not_supp:
err = -ENOTSUPP;
put_file:
fput(file);
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 996162801f7a..f8c4042e5855 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6931,6 +6931,8 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_link {
int (*detach)(struct bpf_link *link);
int (*destroy)(struct bpf_link *link);
+ char *pin_path; /* NULL, if not pinned */
+ int fd; /* hook FD, -1 if not applicable */
bool disconnected;
};
@@ -6960,26 +6962,109 @@ int bpf_link__destroy(struct bpf_link *link)
err = link->detach(link);
if (link->destroy)
link->destroy(link);
+ if (link->pin_path)
+ free(link->pin_path);
free(link);
return err;
}
-struct bpf_link_fd {
- struct bpf_link link; /* has to be at the top of struct */
- int fd; /* hook FD */
-};
+int bpf_link__fd(const struct bpf_link *link)
+{
+ return link->fd;
+}
+
+const char *bpf_link__pin_path(const struct bpf_link *link)
+{
+ return link->pin_path;
+}
+
+static int bpf_link__detach_fd(struct bpf_link *link)
+{
+ return close(link->fd);
+}
+
+struct bpf_link *bpf_link__open(const char *path)
+{
+ struct bpf_link *link;
+ int fd;
+
+ fd = bpf_obj_get(path);
+ if (fd < 0) {
+ fd = -errno;
+ pr_warn("failed to open link at %s: %d\n", path, fd);
+ return ERR_PTR(fd);
+ }
+
+ link = calloc(1, sizeof(*link));
+ if (!link) {
+ close(fd);
+ return ERR_PTR(-ENOMEM);
+ }
+ link->detach = &bpf_link__detach_fd;
+ link->fd = fd;
+
+ link->pin_path = strdup(path);
+ if (!link->pin_path) {
+ bpf_link__destroy(link);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ return link;
+}
+
+int bpf_link__pin(struct bpf_link *link, const char *path)
+{
+ int err;
+
+ if (link->pin_path)
+ return -EBUSY;
+ err = make_parent_dir(path);
+ if (err)
+ return err;
+ err = check_path(path);
+ if (err)
+ return err;
+
+ link->pin_path = strdup(path);
+ if (!link->pin_path)
+ return -ENOMEM;
+
+ if (bpf_obj_pin(link->fd, link->pin_path)) {
+ err = -errno;
+ zfree(&link->pin_path);
+ return err;
+ }
+
+ pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path);
+ return 0;
+}
+
+int bpf_link__unpin(struct bpf_link *link)
+{
+ int err;
+
+ if (!link->pin_path)
+ return -EINVAL;
+
+ err = unlink(link->pin_path);
+ if (err != 0)
+ return -errno;
+
+ pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path);
+ zfree(&link->pin_path);
+ return 0;
+}
static int bpf_link__detach_perf_event(struct bpf_link *link)
{
- struct bpf_link_fd *l = (void *)link;
int err;
- err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
+ err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0);
if (err)
err = -errno;
- close(l->fd);
+ close(link->fd);
return err;
}
@@ -6987,7 +7072,7 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
int pfd)
{
char errmsg[STRERR_BUFSIZE];
- struct bpf_link_fd *link;
+ struct bpf_link *link;
int prog_fd, err;
if (pfd < 0) {
@@ -7005,7 +7090,7 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
- link->link.detach = &bpf_link__detach_perf_event;
+ link->detach = &bpf_link__detach_perf_event;
link->fd = pfd;
if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
@@ -7024,7 +7109,7 @@ struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
- return (struct bpf_link *)link;
+ return link;
}
/*
@@ -7312,18 +7397,11 @@ out:
return link;
}
-static int bpf_link__detach_fd(struct bpf_link *link)
-{
- struct bpf_link_fd *l = (void *)link;
-
- return close(l->fd);
-}
-
struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
- struct bpf_link_fd *link;
+ struct bpf_link *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
@@ -7336,7 +7414,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
- link->link.detach = &bpf_link__detach_fd;
+ link->detach = &bpf_link__detach_fd;
pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
if (pfd < 0) {
@@ -7348,7 +7426,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
return ERR_PTR(pfd);
}
link->fd = pfd;
- return (struct bpf_link *)link;
+ return link;
}
static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
@@ -7362,7 +7440,7 @@ static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
{
char errmsg[STRERR_BUFSIZE];
- struct bpf_link_fd *link;
+ struct bpf_link *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
@@ -7375,7 +7453,7 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
link = calloc(1, sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
- link->link.detach = &bpf_link__detach_fd;
+ link->detach = &bpf_link__detach_fd;
pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
if (pfd < 0) {
@@ -7409,10 +7487,9 @@ struct bpf_link *bpf_program__attach(struct bpf_program *prog)
static int bpf_link__detach_struct_ops(struct bpf_link *link)
{
- struct bpf_link_fd *l = (void *)link;
__u32 zero = 0;
- if (bpf_map_delete_elem(l->fd, &zero))
+ if (bpf_map_delete_elem(link->fd, &zero))
return -errno;
return 0;
@@ -7421,7 +7498,7 @@ static int bpf_link__detach_struct_ops(struct bpf_link *link)
struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
{
struct bpf_struct_ops *st_ops;
- struct bpf_link_fd *link;
+ struct bpf_link *link;
__u32 i, zero = 0;
int err;
@@ -7453,10 +7530,10 @@ struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
return ERR_PTR(err);
}
- link->link.detach = bpf_link__detach_struct_ops;
+ link->detach = bpf_link__detach_struct_ops;
link->fd = map->fd;
- return (struct bpf_link *)link;
+ return link;
}
enum bpf_perf_event_ret
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 02fc58a21a7f..d38d7a629417 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -219,6 +219,11 @@ LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
struct bpf_link;
+LIBBPF_API struct bpf_link *bpf_link__open(const char *path);
+LIBBPF_API int bpf_link__fd(const struct bpf_link *link);
+LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link);
+LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path);
+LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7b014c8cdece..5129283c0284 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -238,5 +238,10 @@ LIBBPF_0.0.7 {
LIBBPF_0.0.8 {
global:
+ bpf_link__fd;
+ bpf_link__open;
+ bpf_link__pin;
+ bpf_link__pin_path;
+ bpf_link__unpin;
bpf_program__set_attach_target;
} LIBBPF_0.0.7;
diff --git a/tools/testing/selftests/bpf/prog_tests/link_pinning.c b/tools/testing/selftests/bpf/prog_tests/link_pinning.c
new file mode 100644
index 000000000000..a743288cf384
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/link_pinning.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include <test_progs.h>
+#include <sys/stat.h>
+
+#include "test_link_pinning.skel.h"
+
+static int duration = 0;
+
+void test_link_pinning_subtest(struct bpf_program *prog,
+ struct test_link_pinning__bss *bss)
+{
+ const char *link_pin_path = "/sys/fs/bpf/pinned_link_test";
+ struct stat statbuf = {};
+ struct bpf_link *link;
+ int err, i;
+
+ link = bpf_program__attach(prog);
+ if (CHECK(IS_ERR(link), "link_attach", "err: %ld\n", PTR_ERR(link)))
+ goto cleanup;
+
+ bss->in = 1;
+ usleep(1);
+ CHECK(bss->out != 1, "res_check1", "exp %d, got %d\n", 1, bss->out);
+
+ /* pin link */
+ err = bpf_link__pin(link, link_pin_path);
+ if (CHECK(err, "link_pin", "err: %d\n", err))
+ goto cleanup;
+
+ CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path1",
+ "exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
+
+ /* check that link was pinned */
+ err = stat(link_pin_path, &statbuf);
+ if (CHECK(err, "stat_link", "err %d errno %d\n", err, errno))
+ goto cleanup;
+
+ bss->in = 2;
+ usleep(1);
+ CHECK(bss->out != 2, "res_check2", "exp %d, got %d\n", 2, bss->out);
+
+ /* destroy link, pinned link should keep program attached */
+ bpf_link__destroy(link);
+ link = NULL;
+
+ bss->in = 3;
+ usleep(1);
+ CHECK(bss->out != 3, "res_check3", "exp %d, got %d\n", 3, bss->out);
+
+ /* re-open link from BPFFS */
+ link = bpf_link__open(link_pin_path);
+ if (CHECK(IS_ERR(link), "link_open", "err: %ld\n", PTR_ERR(link)))
+ goto cleanup;
+
+ CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path2",
+ "exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
+
+ /* unpin link from BPFFS, program still attached */
+ err = bpf_link__unpin(link);
+ if (CHECK(err, "link_unpin", "err: %d\n", err))
+ goto cleanup;
+
+ /* still active, as we have FD open now */
+ bss->in = 4;
+ usleep(1);
+ CHECK(bss->out != 4, "res_check4", "exp %d, got %d\n", 4, bss->out);
+
+ bpf_link__destroy(link);
+ link = NULL;
+
+ /* Validate it's finally detached.
+ * Actual detachment might get delayed a bit, so there is no reliable
+ * way to validate it immediately here, let's count up for long enough
+ * and see if eventually output stops being updated
+ */
+ for (i = 5; i < 10000; i++) {
+ bss->in = i;
+ usleep(1);
+ if (bss->out == i - 1)
+ break;
+ }
+ CHECK(i == 10000, "link_attached", "got to iteration #%d\n", i);
+
+cleanup:
+ if (!IS_ERR(link))
+ bpf_link__destroy(link);
+}
+
+void test_link_pinning(void)
+{
+ struct test_link_pinning* skel;
+
+ skel = test_link_pinning__open_and_load();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+
+ if (test__start_subtest("pin_raw_tp"))
+ test_link_pinning_subtest(skel->progs.raw_tp_prog, skel->bss);
+ if (test__start_subtest("pin_tp_btf"))
+ test_link_pinning_subtest(skel->progs.tp_btf_prog, skel->bss);
+
+ test_link_pinning__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_link_pinning.c b/tools/testing/selftests/bpf/progs/test_link_pinning.c
new file mode 100644
index 000000000000..bbf2a5264dc0
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_link_pinning.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include <stdbool.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+int in = 0;
+int out = 0;
+
+SEC("raw_tp/sys_enter")
+int raw_tp_prog(const void *ctx)
+{
+ out = in;
+ return 0;
+}
+
+SEC("tp_btf/sys_enter")
+int tp_btf_prog(const void *ctx)
+{
+ out = in;
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
generated by cgit v1.2.3 (git 2.39.0) at 2024-09-06 00:43:48 +0300