Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 154 insertions, 0 deletions

diff --git a/src/core/bpf-foreign.c b/src/core/bpf-foreign.c
new file mode 100644
index 0000000..cff2f61
--- /dev/null
+++ b/src/core/bpf-foreign.c
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bpf-foreign.h"
+#include "bpf-program.h"
+#include "cgroup.h"
+#include "memory-util.h"
+#include "missing_magic.h"
+#include "mountpoint-util.h"
+#include "set.h"
+#include "stat-util.h"
+
+typedef struct BPFForeignKey BPFForeignKey;
+struct BPFForeignKey {
+        uint32_t prog_id;
+        uint32_t attach_type;
+};
+
+static int bpf_foreign_key_new(uint32_t prog_id,
+                enum bpf_attach_type attach_type,
+                BPFForeignKey **ret) {
+        _cleanup_free_ BPFForeignKey *p = NULL;
+
+        assert(ret);
+
+        p = new(BPFForeignKey, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (BPFForeignKey) {
+                .prog_id = prog_id,
+                .attach_type = attach_type,
+        };
+
+        *ret = TAKE_PTR(p);
+
+        return 0;
+}
+
+static int bpf_foreign_key_compare_func(const BPFForeignKey *a, const BPFForeignKey *b) {
+        int r = CMP(a->prog_id, b->prog_id);
+        if (r != 0)
+                return r;
+
+        return CMP(a->attach_type, b->attach_type);
+}
+
+static void bpf_foreign_key_hash_func(const BPFForeignKey *p, struct siphash *h) {
+        siphash24_compress(&p->prog_id, sizeof(p->prog_id), h);
+        siphash24_compress(&p->attach_type, sizeof(p->attach_type), h);
+}
+
+DEFINE_PRIVATE_HASH_OPS_FULL(bpf_foreign_by_key_hash_ops,
+                BPFForeignKey, bpf_foreign_key_hash_func, bpf_foreign_key_compare_func, free,
+                BPFProgram, bpf_program_free);
+
+static int attach_programs(Unit *u, const char *path, Hashmap* foreign_by_key, uint32_t attach_flags) {
+        const BPFForeignKey *key;
+        BPFProgram *prog;
+        int r, ret = 0;
+
+        assert(u);
+
+        HASHMAP_FOREACH_KEY(prog, key, foreign_by_key) {
+                r = bpf_program_cgroup_attach(prog, key->attach_type, path, attach_flags);
+                if (r < 0) {
+                        log_unit_error_errno(u, r, "bpf-foreign: Attaching foreign BPF program to cgroup %s failed: %m", path);
+                        if (ret >= 0)
+                                ret = r;
+                }
+        }
+
+        return ret;
+}
+
+/*
+ * Prepare foreign BPF program for installation:
+ * - Load the program from BPF filesystem to the kernel;
+ * - Store program FD identified by program ID and attach type in the unit.
+ */
+static int bpf_foreign_prepare(
+                Unit *u,
+                enum bpf_attach_type attach_type,
+                const char *bpffs_path) {
+        _cleanup_(bpf_program_freep) BPFProgram *prog = NULL;
+        _cleanup_free_ BPFForeignKey *key = NULL;
+        uint32_t prog_id;
+        int r;
+
+        assert(u);
+        assert(bpffs_path);
+
+        r = path_is_fs_type(bpffs_path, BPF_FS_MAGIC);
+        if (r == -ENOENT) {
+                log_unit_warning_errno(u, r, "bpf-foreign: foreign program %s does not exist, skipping.", bpffs_path);
+                return 0;
+        }
+        if (r < 0)
+                return log_unit_error_errno(u, r,
+                                "bpf-foreign: Failed to determine filesystem type of %s: %m", bpffs_path);
+        if (r == 0)
+                return log_unit_error_errno(u, SYNTHETIC_ERRNO(EINVAL),
+                                "bpf-foreign: Path in BPF filesystem is expected.");
+
+        r = bpf_program_new_from_bpffs_path(bpffs_path, &prog);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "bpf-foreign: Failed to create foreign BPF program: %m");
+
+        r = bpf_program_get_id_by_fd(prog->kernel_fd, &prog_id);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "bpf-foreign: Failed to get BPF program id from fd: %m");
+
+        r = bpf_foreign_key_new(prog_id, attach_type, &key);
+        if (r < 0)
+                return log_unit_error_errno(u, r,
+                                "bpf-foreign: Failed to create foreign BPF program key from path '%s': %m", bpffs_path);
+
+        r = hashmap_ensure_put(&u->bpf_foreign_by_key, &bpf_foreign_by_key_hash_ops, key, prog);
+        if (r == -EEXIST) {
+                log_unit_warning_errno(u, r, "bpf-foreign: Foreign BPF program already exists, ignoring: %m");
+                return 0;
+        }
+        if (r < 0)
+                return log_unit_error_errno(u, r, "bpf-foreign: Failed to put foreign BPF program into map: %m");
+
+        TAKE_PTR(key);
+        TAKE_PTR(prog);
+
+        return 0;
+}
+
+int bpf_foreign_install(Unit *u) {
+        _cleanup_free_ char *cgroup_path = NULL;
+        CGroupContext *cc;
+        int r, ret = 0;
+
+        assert(u);
+
+        cc = unit_get_cgroup_context(u);
+        if (!cc)
+                return 0;
+
+        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, NULL, &cgroup_path);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "bpf-foreign: Failed to get cgroup path: %m");
+
+        LIST_FOREACH(programs, p, cc->bpf_foreign_programs) {
+                r = bpf_foreign_prepare(u, p->attach_type, p->bpffs_path);
+                if (r < 0 && ret >= 0)
+                        ret = r;
+        }
+
+        r = attach_programs(u, cgroup_path, u->bpf_foreign_by_key, BPF_F_ALLOW_MULTI);
+        return ret < 0 ? ret : r;
+}