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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/shared/bpf-link.c
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/shared/bpf-link.c')
-rw-r--r--src/shared/bpf-link.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/src/shared/bpf-link.c b/src/shared/bpf-link.c
new file mode 100644
index 0000000..fea49b2
--- /dev/null
+++ b/src/shared/bpf-link.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bpf-dlopen.h"
+#include "bpf-link.h"
+#include "serialize.h"
+
+bool bpf_can_link_program(struct bpf_program *prog) {
+ _cleanup_(bpf_link_freep) struct bpf_link *link = NULL;
+
+ assert(prog);
+
+ if (dlopen_bpf() < 0)
+ return false;
+
+ /* Pass invalid cgroup fd intentionally. */
+ link = sym_bpf_program__attach_cgroup(prog, /*cgroup_fd=*/-1);
+
+ /* EBADF indicates that bpf_link is supported by kernel. */
+ return sym_libbpf_get_error(link) == -EBADF;
+}
+
+int bpf_serialize_link(FILE *f, FDSet *fds, const char *key, struct bpf_link *link) {
+ assert(key);
+
+ if (!link)
+ return -ENOENT;
+
+ if (sym_libbpf_get_error(link) != 0)
+ return -EINVAL;
+
+ return serialize_fd(f, fds, key, sym_bpf_link__fd(link));
+}
+
+struct bpf_link *bpf_link_free(struct bpf_link *link) {
+ /* If libbpf wasn't dlopen()ed, sym_bpf_link__destroy might be unresolved (NULL), so let's not try to
+ * call it if link is NULL. link might also be a non-null "error pointer", but such a value can only
+ * originate from a call to libbpf, but that means that libbpf is available, and we can let
+ * bpf_link__destroy() handle it. */
+ if (link)
+ (void) sym_bpf_link__destroy(link);
+
+ return NULL;
+}