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// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/filter.h>
#include <linux/seccomp.h>
#include <sys/prctl.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "trace_helpers.h"
#include "bpf_util.h"
#ifdef __mips__
#define MAX_ENTRIES 6000 /* MIPS n64 syscalls start at 5000 */
#else
#define MAX_ENTRIES 1024
#endif
/* install fake seccomp program to enable seccomp code path inside the kernel,
* so that our kprobe attached to seccomp_phase1() can be triggered
*/
static void install_accept_all_seccomp(void)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
if (prctl(PR_SET_SECCOMP, 2, &prog))
perror("prctl");
}
int main(int ac, char **argv)
{
struct bpf_link *link = NULL;
struct bpf_program *prog;
struct bpf_object *obj;
int key, fd, progs_fd;
const char *section;
char filename[256];
FILE *f;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
if (!prog) {
printf("finding a prog in obj file failed\n");
goto cleanup;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
link = bpf_program__attach(prog);
if (libbpf_get_error(link)) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
link = NULL;
goto cleanup;
}
progs_fd = bpf_object__find_map_fd_by_name(obj, "progs");
if (progs_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
bpf_object__for_each_program(prog, obj) {
section = bpf_program__section_name(prog);
/* register only syscalls to PROG_ARRAY */
if (sscanf(section, "kprobe/%d", &key) != 1)
continue;
fd = bpf_program__fd(prog);
bpf_map_update_elem(progs_fd, &key, &fd, BPF_ANY);
}
install_accept_all_seccomp();
f = popen("dd if=/dev/zero of=/dev/null count=5", "r");
(void) f;
read_trace_pipe();
cleanup:
bpf_link__destroy(link);
bpf_object__close(obj);
return 0;
}
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