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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3
   4 static volatile int sigusr1_received = 0;
   5
   6 static void sigusr1_handler(int signum)
   7 {
   8         sigusr1_received++;
   9 }
  10
  11 static int test_send_signal_common(struct perf_event_attr *attr,
  12                                     int prog_type,
  13                                     const char *test_name)
  14 {
  15         int err = -1, pmu_fd, prog_fd, info_map_fd, status_map_fd;
  16         const char *file = "./test_send_signal_kern.o";
  17         struct bpf_object *obj = NULL;
  18         int pipe_c2p[2], pipe_p2c[2];
  19         __u32 key = 0, duration = 0;
  20         char buf[256];
  21         pid_t pid;
  22         __u64 val;
  23
  24         if (CHECK(pipe(pipe_c2p), test_name,
  25                   "pipe pipe_c2p error: %s\n", strerror(errno)))
  26                 goto no_fork_done;
  27
  28         if (CHECK(pipe(pipe_p2c), test_name,
  29                   "pipe pipe_p2c error: %s\n", strerror(errno))) {
  30                 close(pipe_c2p[0]);
  31                 close(pipe_c2p[1]);
  32                 goto no_fork_done;
  33         }
  34
  35         pid = fork();
  36         if (CHECK(pid < 0, test_name, "fork error: %s\n", strerror(errno))) {
  37                 close(pipe_c2p[0]);
  38                 close(pipe_c2p[1]);
  39                 close(pipe_p2c[0]);
  40                 close(pipe_p2c[1]);
  41                 goto no_fork_done;
  42         }
  43
  44         if (pid == 0) {
  45                 /* install signal handler and notify parent */
  46                 signal(SIGUSR1, sigusr1_handler);
  47
  48                 close(pipe_c2p[0]); /* close read */
  49                 close(pipe_p2c[1]); /* close write */
  50
  51                 /* notify parent signal handler is installed */
  52                 write(pipe_c2p[1], buf, 1);
  53
  54                 /* make sure parent enabled bpf program to send_signal */
  55                 read(pipe_p2c[0], buf, 1);
  56
  57                 /* wait a little for signal handler */
  58                 sleep(1);
  59
  60                 if (sigusr1_received)
  61                         write(pipe_c2p[1], "2", 1);
  62                 else
  63                         write(pipe_c2p[1], "0", 1);
  64
  65                 /* wait for parent notification and exit */
  66                 read(pipe_p2c[0], buf, 1);
  67
  68                 close(pipe_c2p[1]);
  69                 close(pipe_p2c[0]);
  70                 exit(0);
  71         }
  72
  73         close(pipe_c2p[1]); /* close write */
  74         close(pipe_p2c[0]); /* close read */
  75
  76         err = bpf_prog_load(file, prog_type, &obj, &prog_fd);
  77         if (CHECK(err < 0, test_name, "bpf_prog_load error: %s\n",
  78                   strerror(errno)))
  79                 goto prog_load_failure;
  80
  81         pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
  82                          -1 /* group id */, 0 /* flags */);
  83         if (CHECK(pmu_fd < 0, test_name, "perf_event_open error: %s\n",
  84                   strerror(errno))) {
  85                 err = -1;
  86                 goto close_prog;
  87         }
  88
  89         err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
  90         if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_enable error: %s\n",
  91                   strerror(errno)))
  92                 goto disable_pmu;
  93
  94         err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
  95         if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_set_bpf error: %s\n",
  96                   strerror(errno)))
  97                 goto disable_pmu;
  98
  99         err = -1;
 100         info_map_fd = bpf_object__find_map_fd_by_name(obj, "info_map");
 101         if (CHECK(info_map_fd < 0, test_name, "find map %s error\n", "info_map"))
 102                 goto disable_pmu;
 103
 104         status_map_fd = bpf_object__find_map_fd_by_name(obj, "status_map");
 105         if (CHECK(status_map_fd < 0, test_name, "find map %s error\n", "status_map"))
 106                 goto disable_pmu;
 107
 108         /* wait until child signal handler installed */
 109         read(pipe_c2p[0], buf, 1);
 110
 111         /* trigger the bpf send_signal */
 112         key = 0;
 113         val = (((__u64)(SIGUSR1)) << 32) | pid;
 114         bpf_map_update_elem(info_map_fd, &key, &val, 0);
 115
 116         /* notify child that bpf program can send_signal now */
 117         write(pipe_p2c[1], buf, 1);
 118
 119         /* wait for result */
 120         err = read(pipe_c2p[0], buf, 1);
 121         if (CHECK(err < 0, test_name, "reading pipe error: %s\n", strerror(errno)))
 122                 goto disable_pmu;
 123         if (CHECK(err == 0, test_name, "reading pipe error: size 0\n")) {
 124                 err = -1;
 125                 goto disable_pmu;
 126         }
 127
 128         err = CHECK(buf[0] != '2', test_name, "incorrect result\n");
 129
 130         /* notify child safe to exit */
 131         write(pipe_p2c[1], buf, 1);
 132
 133 disable_pmu:
 134         close(pmu_fd);
 135 close_prog:
 136         bpf_object__close(obj);
 137 prog_load_failure:
 138         close(pipe_c2p[0]);
 139         close(pipe_p2c[1]);
 140         wait(NULL);
 141 no_fork_done:
 142         return err;
 143 }
 144
 145 static int test_send_signal_tracepoint(void)
 146 {
 147         const char *id_path = "/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id";
 148         struct perf_event_attr attr = {
 149                 .type = PERF_TYPE_TRACEPOINT,
 150                 .sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN,
 151                 .sample_period = 1,
 152                 .wakeup_events = 1,
 153         };
 154         __u32 duration = 0;
 155         int bytes, efd;
 156         char buf[256];
 157
 158         efd = open(id_path, O_RDONLY, 0);
 159         if (CHECK(efd < 0, "tracepoint",
 160                   "open syscalls/sys_enter_nanosleep/id failure: %s\n",
 161                   strerror(errno)))
 162                 return -1;
 163
 164         bytes = read(efd, buf, sizeof(buf));
 165         close(efd);
 166         if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "tracepoint",
 167                   "read syscalls/sys_enter_nanosleep/id failure: %s\n",
 168                   strerror(errno)))
 169                 return -1;
 170
 171         attr.config = strtol(buf, NULL, 0);
 172
 173         return test_send_signal_common(&attr, BPF_PROG_TYPE_TRACEPOINT, "tracepoint");
 174 }
 175
 176 static int test_send_signal_nmi(void)
 177 {
 178         struct perf_event_attr attr = {
 179                 .sample_freq = 50,
 180                 .freq = 1,
 181                 .type = PERF_TYPE_HARDWARE,
 182                 .config = PERF_COUNT_HW_CPU_CYCLES,
 183         };
 184
 185         return test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT, "perf_event");
 186 }
 187
 188 void test_send_signal(void)
 189 {
 190         int ret = 0;
 191
 192         ret |= test_send_signal_tracepoint();
 193         ret |= test_send_signal_nmi();
 194         if (!ret)
 195                 printf("test_send_signal:OK\n");
 196         else
 197                 printf("test_send_signal:FAIL\n");
 198 }