tools/bpf: add selftest in test_progs for bpf_send_signal() helper

The test covered both nmi and tracepoint perf events.
  $ ./test_progs
  ...
  test_send_signal_tracepoint:PASS:tracepoint 0 nsec
  ...
  test_send_signal_common:PASS:tracepoint 0 nsec
  ...
  test_send_signal_common:PASS:perf_event 0 nsec
  ...
  test_send_signal:OK

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 4b27840b810921fa77ec4d0e342d5cc3bacd0926..e6d243b7cd74c49ed53ea69156847f105a4c22b2 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -224,6 +224,7 @@ static void *(*bpf_sk_storage_get)(void *map, struct bpf_sock *sk,
        (void *) BPF_FUNC_sk_storage_get;
 static int (*bpf_sk_storage_delete)(void *map, struct bpf_sock *sk) =
        (void *)BPF_FUNC_sk_storage_delete;
+static int (*bpf_send_signal)(unsigned sig) = (void *)BPF_FUNC_send_signal;
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
new file mode 100644 (file)
index 0000000..67cea16
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+static volatile int sigusr1_received = 0;
+
+static void sigusr1_handler(int signum)
+{
+       sigusr1_received++;
+}
+
+static int test_send_signal_common(struct perf_event_attr *attr,
+                                   int prog_type,
+                                   const char *test_name)
+{
+       int err = -1, pmu_fd, prog_fd, info_map_fd, status_map_fd;
+       const char *file = "./test_send_signal_kern.o";
+       struct bpf_object *obj = NULL;
+       int pipe_c2p[2], pipe_p2c[2];
+       __u32 key = 0, duration = 0;
+       char buf[256];
+       pid_t pid;
+       __u64 val;
+
+       if (CHECK(pipe(pipe_c2p), test_name,
+                 "pipe pipe_c2p error: %s\n", strerror(errno)))
+               goto no_fork_done;
+
+       if (CHECK(pipe(pipe_p2c), test_name,
+                 "pipe pipe_p2c error: %s\n", strerror(errno))) {
+               close(pipe_c2p[0]);
+               close(pipe_c2p[1]);
+               goto no_fork_done;
+       }
+
+       pid = fork();
+       if (CHECK(pid < 0, test_name, "fork error: %s\n", strerror(errno))) {
+               close(pipe_c2p[0]);
+               close(pipe_c2p[1]);
+               close(pipe_p2c[0]);
+               close(pipe_p2c[1]);
+               goto no_fork_done;
+       }
+
+       if (pid == 0) {
+               /* install signal handler and notify parent */
+               signal(SIGUSR1, sigusr1_handler);
+
+               close(pipe_c2p[0]); /* close read */
+               close(pipe_p2c[1]); /* close write */
+
+               /* notify parent signal handler is installed */
+               write(pipe_c2p[1], buf, 1);
+
+               /* make sure parent enabled bpf program to send_signal */
+               read(pipe_p2c[0], buf, 1);
+
+               /* wait a little for signal handler */
+               sleep(1);
+
+               if (sigusr1_received)
+                       write(pipe_c2p[1], "2", 1);
+               else
+                       write(pipe_c2p[1], "0", 1);
+
+               /* wait for parent notification and exit */
+               read(pipe_p2c[0], buf, 1);
+
+               close(pipe_c2p[1]);
+               close(pipe_p2c[0]);
+               exit(0);
+       }
+
+       close(pipe_c2p[1]); /* close write */
+       close(pipe_p2c[0]); /* close read */
+
+       err = bpf_prog_load(file, prog_type, &obj, &prog_fd);
+       if (CHECK(err < 0, test_name, "bpf_prog_load error: %s\n",
+                 strerror(errno)))
+               goto prog_load_failure;
+
+       pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
+                        -1 /* group id */, 0 /* flags */);
+       if (CHECK(pmu_fd < 0, test_name, "perf_event_open error: %s\n",
+                 strerror(errno))) {
+               err = -1;
+               goto close_prog;
+       }
+
+       err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
+       if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_enable error: %s\n",
+                 strerror(errno)))
+               goto disable_pmu;
+
+       err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
+       if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_set_bpf error: %s\n",
+                 strerror(errno)))
+               goto disable_pmu;
+
+       err = -1;
+       info_map_fd = bpf_object__find_map_fd_by_name(obj, "info_map");
+       if (CHECK(info_map_fd < 0, test_name, "find map %s error\n", "info_map"))
+               goto disable_pmu;
+
+       status_map_fd = bpf_object__find_map_fd_by_name(obj, "status_map");
+       if (CHECK(status_map_fd < 0, test_name, "find map %s error\n", "status_map"))
+               goto disable_pmu;
+
+       /* wait until child signal handler installed */
+       read(pipe_c2p[0], buf, 1);
+
+       /* trigger the bpf send_signal */
+       key = 0;
+       val = (((__u64)(SIGUSR1)) << 32) | pid;
+       bpf_map_update_elem(info_map_fd, &key, &val, 0);
+
+       /* notify child that bpf program can send_signal now */
+       write(pipe_p2c[1], buf, 1);
+
+       /* wait for result */
+       err = read(pipe_c2p[0], buf, 1);
+       if (CHECK(err < 0, test_name, "reading pipe error: %s\n", strerror(errno)))
+               goto disable_pmu;
+       if (CHECK(err == 0, test_name, "reading pipe error: size 0\n")) {
+               err = -1;
+               goto disable_pmu;
+       }
+
+       err = CHECK(buf[0] != '2', test_name, "incorrect result\n");
+
+       /* notify child safe to exit */
+       write(pipe_p2c[1], buf, 1);
+
+disable_pmu:
+       close(pmu_fd);
+close_prog:
+       bpf_object__close(obj);
+prog_load_failure:
+       close(pipe_c2p[0]);
+       close(pipe_p2c[1]);
+       wait(NULL);
+no_fork_done:
+       return err;
+}
+
+static int test_send_signal_tracepoint(void)
+{
+       const char *id_path = "/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id";
+       struct perf_event_attr attr = {
+               .type = PERF_TYPE_TRACEPOINT,
+               .sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN,
+               .sample_period = 1,
+               .wakeup_events = 1,
+       };
+       __u32 duration = 0;
+       int bytes, efd;
+       char buf[256];
+
+       efd = open(id_path, O_RDONLY, 0);
+       if (CHECK(efd < 0, "tracepoint",
+                 "open syscalls/sys_enter_nanosleep/id failure: %s\n",
+                 strerror(errno)))
+               return -1;
+
+       bytes = read(efd, buf, sizeof(buf));
+       close(efd);
+       if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "tracepoint",
+                 "read syscalls/sys_enter_nanosleep/id failure: %s\n",
+                 strerror(errno)))
+               return -1;
+
+       attr.config = strtol(buf, NULL, 0);
+
+       return test_send_signal_common(&attr, BPF_PROG_TYPE_TRACEPOINT, "tracepoint");
+}
+
+static int test_send_signal_nmi(void)
+{
+       struct perf_event_attr attr = {
+               .sample_freq = 50,
+               .freq = 1,
+               .type = PERF_TYPE_HARDWARE,
+               .config = PERF_COUNT_HW_CPU_CYCLES,
+       };
+
+       return test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT, "perf_event");
+}
+
+void test_send_signal(void)
+{
+       int ret = 0;
+
+       ret |= test_send_signal_tracepoint();
+       ret |= test_send_signal_nmi();
+       if (!ret)
+               printf("test_send_signal:OK\n");
+       else
+               printf("test_send_signal:FAIL\n");
+}

diff --git a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
new file mode 100644 (file)
index 0000000..45a1a1a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include <linux/version.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") info_map = {
+       .type = BPF_MAP_TYPE_ARRAY,
+       .key_size = sizeof(__u32),
+       .value_size = sizeof(__u64),
+       .max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(info_map, __u32, __u64);
+
+struct bpf_map_def SEC("maps") status_map = {
+       .type = BPF_MAP_TYPE_ARRAY,
+       .key_size = sizeof(__u32),
+       .value_size = sizeof(__u64),
+       .max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(status_map, __u32, __u64);
+
+SEC("send_signal_demo")
+int bpf_send_signal_test(void *ctx)
+{
+       __u64 *info_val, *status_val;
+       __u32 key = 0, pid, sig;
+       int ret;
+
+       status_val = bpf_map_lookup_elem(&status_map, &key);
+       if (!status_val || *status_val != 0)
+               return 0;
+
+       info_val = bpf_map_lookup_elem(&info_map, &key);
+       if (!info_val || *info_val == 0)
+               return 0;
+
+       sig = *info_val >> 32;
+       pid = *info_val & 0xffffFFFF;
+
+       if ((bpf_get_current_pid_tgid() >> 32) == pid) {
+               ret = bpf_send_signal(sig);
+               if (ret == 0)
+                       *status_val = 1;
+       }
+
+       return 0;
+}
+char __license[] SEC("license") = "GPL";