| 1 | // SPDX-License-Identifier: GPL-2.0 |
|---|---|
| 2 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 3 | #include <linux/init.h> |
| 4 | #include <linux/module.h> |
| 5 | #include "bpf_preload.h" |
| 6 | #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ |
| 7 | #include "iterators/iterators.lskel-little-endian.h" |
| 8 | #else |
| 9 | #include "iterators/iterators.lskel-big-endian.h" |
| 10 | #endif |
| 11 | |
| 12 | static struct bpf_link *maps_link, *progs_link; |
| 13 | static struct iterators_bpf *skel; |
| 14 | |
| 15 | static void free_links_and_skel(void) |
| 16 | { |
| 17 | if (!IS_ERR_OR_NULL(ptr: maps_link)) |
| 18 | bpf_link_put(maps_link); |
| 19 | if (!IS_ERR_OR_NULL(ptr: progs_link)) |
| 20 | bpf_link_put(progs_link); |
| 21 | iterators_bpf__destroy(skel); |
| 22 | } |
| 23 | |
| 24 | static int preload(struct bpf_preload_info *obj) |
| 25 | { |
| 26 | strscpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name)); |
| 27 | obj[0].link = maps_link; |
| 28 | strscpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name)); |
| 29 | obj[1].link = progs_link; |
| 30 | return 0; |
| 31 | } |
| 32 | |
| 33 | static struct bpf_preload_ops ops = { |
| 34 | .preload = preload, |
| 35 | .owner = THIS_MODULE, |
| 36 | }; |
| 37 | |
| 38 | static int load_skel(void) |
| 39 | { |
| 40 | int err; |
| 41 | |
| 42 | skel = iterators_bpf__open(); |
| 43 | if (!skel) |
| 44 | return -ENOMEM; |
| 45 | err = iterators_bpf__load(skel); |
| 46 | if (err) |
| 47 | goto out; |
| 48 | err = iterators_bpf__attach(skel); |
| 49 | if (err) |
| 50 | goto out; |
| 51 | maps_link = bpf_link_get_from_fd(skel->links.dump_bpf_map_fd); |
| 52 | if (IS_ERR(ptr: maps_link)) { |
| 53 | err = PTR_ERR(ptr: maps_link); |
| 54 | goto out; |
| 55 | } |
| 56 | progs_link = bpf_link_get_from_fd(skel->links.dump_bpf_prog_fd); |
| 57 | if (IS_ERR(ptr: progs_link)) { |
| 58 | err = PTR_ERR(ptr: progs_link); |
| 59 | goto out; |
| 60 | } |
| 61 | /* Avoid taking over stdin/stdout/stderr of init process. Zeroing out |
| 62 | * makes skel_closenz() a no-op later in iterators_bpf__destroy(). |
| 63 | */ |
| 64 | close_fd(skel->links.dump_bpf_map_fd); |
| 65 | skel->links.dump_bpf_map_fd = 0; |
| 66 | close_fd(skel->links.dump_bpf_prog_fd); |
| 67 | skel->links.dump_bpf_prog_fd = 0; |
| 68 | return 0; |
| 69 | out: |
| 70 | free_links_and_skel(); |
| 71 | return err; |
| 72 | } |
| 73 | |
| 74 | static int __init load(void) |
| 75 | { |
| 76 | int err; |
| 77 | |
| 78 | err = load_skel(); |
| 79 | if (err) |
| 80 | return err; |
| 81 | bpf_preload_ops = &ops; |
| 82 | return err; |
| 83 | } |
| 84 | |
| 85 | static void __exit fini(void) |
| 86 | { |
| 87 | bpf_preload_ops = NULL; |
| 88 | free_links_and_skel(); |
| 89 | } |
| 90 | late_initcall(load); |
| 91 | module_exit(fini); |
| 92 | MODULE_LICENSE("GPL"); |
| 93 |