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