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f88886de09
Add namespace to BPF internal symbols used by light skeleton
to prevent abuse and document with the code their allowed usage.
Fixes: b1d18a7574 ("bpf: Extend sys_bpf commands for bpf_syscall programs.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20250425014542.62385-1-alexei.starovoitov@gmail.com
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/module.h>
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#include "bpf_preload.h"
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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#include "iterators/iterators.lskel-little-endian.h"
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#else
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#include "iterators/iterators.lskel-big-endian.h"
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#endif
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static struct bpf_link *maps_link, *progs_link;
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static struct iterators_bpf *skel;
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static void free_links_and_skel(void)
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{
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if (!IS_ERR_OR_NULL(maps_link))
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bpf_link_put(maps_link);
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if (!IS_ERR_OR_NULL(progs_link))
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bpf_link_put(progs_link);
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iterators_bpf__destroy(skel);
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}
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static int preload(struct bpf_preload_info *obj)
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{
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strscpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
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obj[0].link = maps_link;
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strscpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
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obj[1].link = progs_link;
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return 0;
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}
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static struct bpf_preload_ops ops = {
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.preload = preload,
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.owner = THIS_MODULE,
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};
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static int load_skel(void)
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{
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int err;
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skel = iterators_bpf__open();
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if (!skel)
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return -ENOMEM;
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err = iterators_bpf__load(skel);
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if (err)
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goto out;
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err = iterators_bpf__attach(skel);
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if (err)
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goto out;
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maps_link = bpf_link_get_from_fd(skel->links.dump_bpf_map_fd);
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if (IS_ERR(maps_link)) {
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err = PTR_ERR(maps_link);
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goto out;
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}
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progs_link = bpf_link_get_from_fd(skel->links.dump_bpf_prog_fd);
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if (IS_ERR(progs_link)) {
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err = PTR_ERR(progs_link);
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goto out;
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}
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/* Avoid taking over stdin/stdout/stderr of init process. Zeroing out
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* makes skel_closenz() a no-op later in iterators_bpf__destroy().
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*/
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close_fd(skel->links.dump_bpf_map_fd);
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skel->links.dump_bpf_map_fd = 0;
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close_fd(skel->links.dump_bpf_prog_fd);
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skel->links.dump_bpf_prog_fd = 0;
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return 0;
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out:
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free_links_and_skel();
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return err;
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}
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static int __init load(void)
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{
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int err;
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err = load_skel();
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if (err)
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return err;
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bpf_preload_ops = &ops;
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return err;
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}
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static void __exit fini(void)
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{
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bpf_preload_ops = NULL;
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free_links_and_skel();
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}
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late_initcall(load);
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module_exit(fini);
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MODULE_IMPORT_NS("BPF_INTERNAL");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Embedded BPF programs for introspection in bpffs");
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