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// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "test_send_signal_kern.skel.h"
static int sigusr1_received;
static void sigusr1_handler(int signum)
{
sigusr1_received = 1;
}
static void test_send_signal_common(struct perf_event_attr *attr,
bool signal_thread)
{
struct test_send_signal_kern *skel;
int pipe_c2p[2], pipe_p2c[2];
int err = -1, pmu_fd = -1;
char buf[256];
pid_t pid;
if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p"))
return;
if (!ASSERT_OK(pipe(pipe_p2c), "pipe_p2c")) {
close(pipe_c2p[0]);
close(pipe_c2p[1]);
return;
}
pid = fork();
if (!ASSERT_GE(pid, 0, "fork")) {
close(pipe_c2p[0]);
close(pipe_c2p[1]);
close(pipe_p2c[0]);
close(pipe_p2c[1]);
return;
}
if (pid == 0) {
int old_prio;
volatile int j = 0;
/* install signal handler and notify parent */
ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
close(pipe_c2p[0]); /* close read */
close(pipe_p2c[1]); /* close write */
/* boost with a high priority so we got a higher chance
* that if an interrupt happens, the underlying task
* is this process.
*/
errno = 0;
old_prio = getpriority(PRIO_PROCESS, 0);
ASSERT_OK(errno, "getpriority");
ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
/* notify parent signal handler is installed */
ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
/* make sure parent enabled bpf program to send_signal */
ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");
/* wait a little for signal handler */
for (int i = 0; i < 1000000000 && !sigusr1_received; i++) {
j /= i + j + 1;
if (!attr)
/* trigger the nanosleep tracepoint program. */
usleep(1);
}
buf[0] = sigusr1_received ? '2' : '0';
ASSERT_EQ(sigusr1_received, 1, "sigusr1_received");
ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
/* wait for parent notification and exit */
ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");
/* restore the old priority */
ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
close(pipe_c2p[1]);
close(pipe_p2c[0]);
exit(0);
}
close(pipe_c2p[1]); /* close write */
close(pipe_p2c[0]); /* close read */
skel = test_send_signal_kern__open_and_load();
if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
goto skel_open_load_failure;
if (!attr) {
err = test_send_signal_kern__attach(skel);
if (!ASSERT_OK(err, "skel_attach")) {
err = -1;
goto destroy_skel;
}
} else {
pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
-1 /* group id */, 0 /* flags */);
if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) {
err = -1;
goto destroy_skel;
}
skel->links.send_signal_perf =
bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd);
if (!ASSERT_OK_PTR(skel->links.send_signal_perf, "attach_perf_event"))
goto disable_pmu;
}
/* wait until child signal handler installed */
ASSERT_EQ(read(pipe_c2p[0], buf, 1), 1, "pipe_read");
/* trigger the bpf send_signal */
skel->bss->signal_thread = signal_thread;
skel->bss->sig = SIGUSR1;
skel->bss->pid = pid;
/* notify child that bpf program can send_signal now */
ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
/* wait for result */
err = read(pipe_c2p[0], buf, 1);
if (!ASSERT_GE(err, 0, "reading pipe"))
goto disable_pmu;
if (!ASSERT_GT(err, 0, "reading pipe error: size 0")) {
err = -1;
goto disable_pmu;
}
ASSERT_EQ(buf[0], '2', "incorrect result");
/* notify child safe to exit */
ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
disable_pmu:
close(pmu_fd);
destroy_skel:
test_send_signal_kern__destroy(skel);
skel_open_load_failure:
close(pipe_c2p[0]);
close(pipe_p2c[1]);
wait(NULL);
}
static void test_send_signal_tracepoint(bool signal_thread)
{
test_send_signal_common(NULL, signal_thread);
}
static void test_send_signal_perf(bool signal_thread)
{
struct perf_event_attr attr = {
.freq = 1,
.sample_freq = 1000,
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
};
test_send_signal_common(&attr, signal_thread);
}
static void test_send_signal_nmi(bool signal_thread)
{
struct perf_event_attr attr = {
.sample_period = 1,
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
};
int pmu_fd;
/* Some setups (e.g. virtual machines) might run with hardware
* perf events disabled. If this is the case, skip this test.
*/
pmu_fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */,
-1 /* cpu */, -1 /* group_fd */, 0 /* flags */);
if (pmu_fd == -1) {
if (errno == ENOENT || errno == EOPNOTSUPP) {
printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n",
__func__);
test__skip();
return;
}
/* Let the test fail with a more informative message */
} else {
close(pmu_fd);
}
test_send_signal_common(&attr, signal_thread);
}
void test_send_signal(void)
{
if (test__start_subtest("send_signal_tracepoint"))
test_send_signal_tracepoint(false);
if (test__start_subtest("send_signal_perf"))
test_send_signal_perf(false);
if (test__start_subtest("send_signal_nmi"))
test_send_signal_nmi(false);
if (test__start_subtest("send_signal_tracepoint_thread"))
test_send_signal_tracepoint(true);
if (test__start_subtest("send_signal_perf_thread"))
test_send_signal_perf(true);
if (test__start_subtest("send_signal_nmi_thread"))
test_send_signal_nmi(true);
}
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