// SPDX-License-Identifier: GPL-2.0-only
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#define _GNU_SOURCE
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#include <sched.h>
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#include <sys/prctl.h>
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#include <test_progs.h>
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#define MAX_TRAMP_PROGS 40
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struct inst {
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struct bpf_object *obj;
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struct bpf_link *link_fentry;
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struct bpf_link *link_fexit;
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};
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static int test_task_rename(void)
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{
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int fd, duration = 0, err;
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char buf[] = "test_overhead";
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fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
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if (CHECK(fd < 0, "open /proc", "err %d", errno))
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return -1;
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err = write(fd, buf, sizeof(buf));
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if (err < 0) {
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CHECK(err < 0, "task rename", "err %d", errno);
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close(fd);
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return -1;
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}
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close(fd);
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return 0;
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}
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static struct bpf_link *load(struct bpf_object *obj, const char *name)
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{
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struct bpf_program *prog;
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int duration = 0;
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prog = bpf_object__find_program_by_title(obj, name);
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if (CHECK(!prog, "find_probe", "prog '%s' not found\n", name))
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return ERR_PTR(-EINVAL);
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return bpf_program__attach_trace(prog);
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}
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void test_trampoline_count(void)
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{
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const char *fentry_name = "fentry/__set_task_comm";
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const char *fexit_name = "fexit/__set_task_comm";
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const char *object = "test_trampoline_count.o";
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struct inst inst[MAX_TRAMP_PROGS] = {};
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int err, i = 0, duration = 0;
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struct bpf_object *obj;
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struct bpf_link *link;
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char comm[16] = {};
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/* attach 'allowed' 40 trampoline programs */
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for (i = 0; i < MAX_TRAMP_PROGS; i++) {
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obj = bpf_object__open_file(object, NULL);
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if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) {
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obj = NULL;
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goto cleanup;
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}
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err = bpf_object__load(obj);
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if (CHECK(err, "obj_load", "err %d\n", err))
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goto cleanup;
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inst[i].obj = obj;
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obj = NULL;
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if (rand() % 2) {
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link = load(inst[i].obj, fentry_name);
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if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link))) {
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link = NULL;
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goto cleanup;
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}
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inst[i].link_fentry = link;
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} else {
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link = load(inst[i].obj, fexit_name);
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if (CHECK(IS_ERR(link), "attach prog", "err %ld\n", PTR_ERR(link))) {
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link = NULL;
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goto cleanup;
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}
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inst[i].link_fexit = link;
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}
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}
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/* and try 1 extra.. */
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obj = bpf_object__open_file(object, NULL);
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if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) {
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obj = NULL;
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goto cleanup;
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}
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err = bpf_object__load(obj);
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if (CHECK(err, "obj_load", "err %d\n", err))
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goto cleanup_extra;
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/* ..that needs to fail */
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link = load(obj, fentry_name);
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if (CHECK(!IS_ERR(link), "cannot attach over the limit", "err %ld\n", PTR_ERR(link))) {
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bpf_link__destroy(link);
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goto cleanup_extra;
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}
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/* with E2BIG error */
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CHECK(PTR_ERR(link) != -E2BIG, "proper error check", "err %ld\n", PTR_ERR(link));
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/* and finaly execute the probe */
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if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
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goto cleanup_extra;
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CHECK_FAIL(test_task_rename());
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CHECK_FAIL(prctl(PR_SET_NAME, comm, 0L, 0L, 0L));
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cleanup_extra:
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bpf_object__close(obj);
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cleanup:
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if (i >= MAX_TRAMP_PROGS)
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i = MAX_TRAMP_PROGS - 1;
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for (; i >= 0; i--) {
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bpf_link__destroy(inst[i].link_fentry);
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bpf_link__destroy(inst[i].link_fexit);
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bpf_object__close(inst[i].obj);
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}
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}
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