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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include <sys/mount.h>
#include "iterators.skel.h"
#include "bpf_preload_common.h"
int to_kernel = -1;
int from_kernel = 0;
static int send_link_to_kernel(struct bpf_link *link, const char *link_name)
{
struct bpf_preload_info obj = {};
struct bpf_link_info info = {};
__u32 info_len = sizeof(info);
int err;
err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &info, &info_len);
if (err)
return err;
obj.link_id = info.id;
if (strlen(link_name) >= sizeof(obj.link_name))
return -E2BIG;
strcpy(obj.link_name, link_name);
if (write(to_kernel, &obj, sizeof(obj)) != sizeof(obj))
return -EPIPE;
return 0;
}
int main(int argc, char **argv)
{
struct rlimit rlim = { RLIM_INFINITY, RLIM_INFINITY };
struct iterators_bpf *skel;
int err, magic;
int debug_fd;
debug_fd = open("/dev/console", O_WRONLY | O_NOCTTY | O_CLOEXEC);
if (debug_fd < 0)
return 1;
to_kernel = dup(1);
close(1);
dup(debug_fd);
/* now stdin and stderr point to /dev/console */
read(from_kernel, &magic, sizeof(magic));
if (magic != BPF_PRELOAD_START) {
printf("bad start magic %d\n", magic);
return 1;
}
setrlimit(RLIMIT_MEMLOCK, &rlim);
/* libbpf opens BPF object and loads it into the kernel */
skel = iterators_bpf__open_and_load();
if (!skel) {
/* iterators.skel.h is little endian.
* libbpf doesn't support automatic little->big conversion
* of BPF bytecode yet.
* The program load will fail in such case.
*/
printf("Failed load could be due to wrong endianness\n");
return 1;
}
err = iterators_bpf__attach(skel);
if (err)
goto cleanup;
/* send two bpf_link IDs with names to the kernel */
err = send_link_to_kernel(skel->links.dump_bpf_map, "maps.debug");
if (err)
goto cleanup;
err = send_link_to_kernel(skel->links.dump_bpf_prog, "progs.debug");
if (err)
goto cleanup;
/* The kernel will proceed with pinnging the links in bpffs.
* UMD will wait on read from pipe.
*/
read(from_kernel, &magic, sizeof(magic));
if (magic != BPF_PRELOAD_END) {
printf("bad final magic %d\n", magic);
err = -EINVAL;
}
cleanup:
iterators_bpf__destroy(skel);
return err != 0;
}
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