tools/testing/selftests/bpf/prog_tests/send_signal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3 #include "test_send_signal_kern.skel.h"
   4
   5 static volatile int sigusr1_received = 0;
   6
   7 static void sigusr1_handler(int signum)
   8 {
   9         sigusr1_received++;
  10 }
  11
  12 static void test_send_signal_common(struct perf_event_attr *attr,
  13                                     bool signal_thread,
  14                                     const char *test_name)
  15 {
  16         struct test_send_signal_kern *skel;
  17         int pipe_c2p[2], pipe_p2c[2];
  18         int err = -1, pmu_fd = -1;
  19         __u32 duration = 0;
  20         char buf[256];
  21         pid_t pid;
  22
  23         if (CHECK(pipe(pipe_c2p), test_name,
  24                   "pipe pipe_c2p error: %s\n", strerror(errno)))
  25                 return;
  26
  27         if (CHECK(pipe(pipe_p2c), test_name,
  28                   "pipe pipe_p2c error: %s\n", strerror(errno))) {
  29                 close(pipe_c2p[0]);
  30                 close(pipe_c2p[1]);
  31                 return;
  32         }
  33
  34         pid = fork();
  35         if (CHECK(pid < 0, test_name, "fork error: %s\n", strerror(errno))) {
  36                 close(pipe_c2p[0]);
  37                 close(pipe_c2p[1]);
  38                 close(pipe_p2c[0]);
  39                 close(pipe_p2c[1]);
  40                 return;
  41         }
  42
  43         if (pid == 0) {
  44                 /* install signal handler and notify parent */
  45                 signal(SIGUSR1, sigusr1_handler);
  46
  47                 close(pipe_c2p[0]); /* close read */
  48                 close(pipe_p2c[1]); /* close write */
  49
  50                 /* notify parent signal handler is installed */
  51                 write(pipe_c2p[1], buf, 1);
  52
  53                 /* make sure parent enabled bpf program to send_signal */
  54                 read(pipe_p2c[0], buf, 1);
  55
  56                 /* wait a little for signal handler */
  57                 sleep(1);
  58
  59                 if (sigusr1_received)
  60                         write(pipe_c2p[1], "2", 1);
  61                 else
  62                         write(pipe_c2p[1], "0", 1);
  63
  64                 /* wait for parent notification and exit */
  65                 read(pipe_p2c[0], buf, 1);
  66
  67                 close(pipe_c2p[1]);
  68                 close(pipe_p2c[0]);
  69                 exit(0);
  70         }
  71
  72         close(pipe_c2p[1]); /* close write */
  73         close(pipe_p2c[0]); /* close read */
  74
  75         skel = test_send_signal_kern__open_and_load();
  76         if (CHECK(!skel, "skel_open_and_load", "skeleton open_and_load failed\n"))
  77                 goto skel_open_load_failure;
  78
  79         if (!attr) {
  80                 err = test_send_signal_kern__attach(skel);
  81                 if (CHECK(err, "skel_attach", "skeleton attach failed\n")) {
  82                         err = -1;
  83                         goto destroy_skel;
  84                 }
  85         } else {
  86                 pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
  87                                  -1 /* group id */, 0 /* flags */);
  88                 if (CHECK(pmu_fd < 0, test_name, "perf_event_open error: %s\n",
  89                         strerror(errno))) {
  90                         err = -1;
  91                         goto destroy_skel;
  92                 }
  93
  94                 skel->links.send_signal_perf =
  95                         bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd);
  96                 if (CHECK(IS_ERR(skel->links.send_signal_perf), "attach_perf_event",
  97                           "err %ld\n", PTR_ERR(skel->links.send_signal_perf)))
  98                         goto disable_pmu;
  99         }
 100
 101         /* wait until child signal handler installed */
 102         read(pipe_c2p[0], buf, 1);
 103
 104         /* trigger the bpf send_signal */
 105         skel->bss->pid = pid;
 106         skel->bss->sig = SIGUSR1;
 107         skel->bss->signal_thread = signal_thread;
 108
 109         /* notify child that bpf program can send_signal now */
 110         write(pipe_p2c[1], buf, 1);
 111
 112         /* wait for result */
 113         err = read(pipe_c2p[0], buf, 1);
 114         if (CHECK(err < 0, test_name, "reading pipe error: %s\n", strerror(errno)))
 115                 goto disable_pmu;
 116         if (CHECK(err == 0, test_name, "reading pipe error: size 0\n")) {
 117                 err = -1;
 118                 goto disable_pmu;
 119         }
 120
 121         CHECK(buf[0] != '2', test_name, "incorrect result\n");
 122
 123         /* notify child safe to exit */
 124         write(pipe_p2c[1], buf, 1);
 125
 126 disable_pmu:
 127         close(pmu_fd);
 128 destroy_skel:
 129         test_send_signal_kern__destroy(skel);
 130 skel_open_load_failure:
 131         close(pipe_c2p[0]);
 132         close(pipe_p2c[1]);
 133         wait(NULL);
 134 }
 135
 136 static void test_send_signal_tracepoint(bool signal_thread)
 137 {
 138         test_send_signal_common(NULL, signal_thread, "tracepoint");
 139 }
 140
 141 static void test_send_signal_perf(bool signal_thread)
 142 {
 143         struct perf_event_attr attr = {
 144                 .sample_period = 1,
 145                 .type = PERF_TYPE_SOFTWARE,
 146                 .config = PERF_COUNT_SW_CPU_CLOCK,
 147         };
 148
 149         test_send_signal_common(&attr, signal_thread, "perf_sw_event");
 150 }
 151
 152 static void test_send_signal_nmi(bool signal_thread)
 153 {
 154         struct perf_event_attr attr = {
 155                 .sample_period = 1,
 156                 .type = PERF_TYPE_HARDWARE,
 157                 .config = PERF_COUNT_HW_CPU_CYCLES,
 158         };
 159         int pmu_fd;
 160
 161         /* Some setups (e.g. virtual machines) might run with hardware
 162          * perf events disabled. If this is the case, skip this test.
 163          */
 164         pmu_fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */,
 165                          -1 /* cpu */, -1 /* group_fd */, 0 /* flags */);
 166         if (pmu_fd == -1) {
 167                 if (errno == ENOENT) {
 168                         printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n",
 169                                __func__);
 170                         test__skip();
 171                         return;
 172                 }
 173                 /* Let the test fail with a more informative message */
 174         } else {
 175                 close(pmu_fd);
 176         }
 177
 178         test_send_signal_common(&attr, signal_thread, "perf_hw_event");
 179 }
 180
 181 void test_send_signal(void)
 182 {
 183         if (test__start_subtest("send_signal_tracepoint"))
 184                 test_send_signal_tracepoint(false);
 185         if (test__start_subtest("send_signal_perf"))
 186                 test_send_signal_perf(false);
 187         if (test__start_subtest("send_signal_nmi"))
 188                 test_send_signal_nmi(false);
 189         if (test__start_subtest("send_signal_tracepoint_thread"))
 190                 test_send_signal_tracepoint(true);
 191         if (test__start_subtest("send_signal_perf_thread"))
 192                 test_send_signal_perf(true);
 193         if (test__start_subtest("send_signal_nmi_thread"))
 194                 test_send_signal_nmi(true);
 195 }