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