send_signal.c (5325B)
1// SPDX-License-Identifier: GPL-2.0 2#include <test_progs.h> 3#include <sys/time.h> 4#include <sys/resource.h> 5#include "test_send_signal_kern.skel.h" 6 7static int sigusr1_received; 8 9static void sigusr1_handler(int signum) 10{ 11 sigusr1_received = 1; 12} 13 14static void test_send_signal_common(struct perf_event_attr *attr, 15 bool signal_thread) 16{ 17 struct test_send_signal_kern *skel; 18 int pipe_c2p[2], pipe_p2c[2]; 19 int err = -1, pmu_fd = -1; 20 char buf[256]; 21 pid_t pid; 22 23 if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p")) 24 return; 25 26 if (!ASSERT_OK(pipe(pipe_p2c), "pipe_p2c")) { 27 close(pipe_c2p[0]); 28 close(pipe_c2p[1]); 29 return; 30 } 31 32 pid = fork(); 33 if (!ASSERT_GE(pid, 0, "fork")) { 34 close(pipe_c2p[0]); 35 close(pipe_c2p[1]); 36 close(pipe_p2c[0]); 37 close(pipe_p2c[1]); 38 return; 39 } 40 41 if (pid == 0) { 42 int old_prio; 43 volatile int j = 0; 44 45 /* install signal handler and notify parent */ 46 ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal"); 47 48 close(pipe_c2p[0]); /* close read */ 49 close(pipe_p2c[1]); /* close write */ 50 51 /* boost with a high priority so we got a higher chance 52 * that if an interrupt happens, the underlying task 53 * is this process. 54 */ 55 errno = 0; 56 old_prio = getpriority(PRIO_PROCESS, 0); 57 ASSERT_OK(errno, "getpriority"); 58 ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority"); 59 60 /* notify parent signal handler is installed */ 61 ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); 62 63 /* make sure parent enabled bpf program to send_signal */ 64 ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read"); 65 66 /* wait a little for signal handler */ 67 for (int i = 0; i < 100000000 && !sigusr1_received; i++) 68 j /= i + j + 1; 69 70 buf[0] = sigusr1_received ? '2' : '0'; 71 ASSERT_EQ(sigusr1_received, 1, "sigusr1_received"); 72 ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); 73 74 /* wait for parent notification and exit */ 75 ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read"); 76 77 /* restore the old priority */ 78 ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority"); 79 80 close(pipe_c2p[1]); 81 close(pipe_p2c[0]); 82 exit(0); 83 } 84 85 close(pipe_c2p[1]); /* close write */ 86 close(pipe_p2c[0]); /* close read */ 87 88 skel = test_send_signal_kern__open_and_load(); 89 if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) 90 goto skel_open_load_failure; 91 92 if (!attr) { 93 err = test_send_signal_kern__attach(skel); 94 if (!ASSERT_OK(err, "skel_attach")) { 95 err = -1; 96 goto destroy_skel; 97 } 98 } else { 99 pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */, 100 -1 /* group id */, 0 /* flags */); 101 if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) { 102 err = -1; 103 goto destroy_skel; 104 } 105 106 skel->links.send_signal_perf = 107 bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd); 108 if (!ASSERT_OK_PTR(skel->links.send_signal_perf, "attach_perf_event")) 109 goto disable_pmu; 110 } 111 112 /* wait until child signal handler installed */ 113 ASSERT_EQ(read(pipe_c2p[0], buf, 1), 1, "pipe_read"); 114 115 /* trigger the bpf send_signal */ 116 skel->bss->signal_thread = signal_thread; 117 skel->bss->sig = SIGUSR1; 118 skel->bss->pid = pid; 119 120 /* notify child that bpf program can send_signal now */ 121 ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); 122 123 /* wait for result */ 124 err = read(pipe_c2p[0], buf, 1); 125 if (!ASSERT_GE(err, 0, "reading pipe")) 126 goto disable_pmu; 127 if (!ASSERT_GT(err, 0, "reading pipe error: size 0")) { 128 err = -1; 129 goto disable_pmu; 130 } 131 132 ASSERT_EQ(buf[0], '2', "incorrect result"); 133 134 /* notify child safe to exit */ 135 ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); 136 137disable_pmu: 138 close(pmu_fd); 139destroy_skel: 140 test_send_signal_kern__destroy(skel); 141skel_open_load_failure: 142 close(pipe_c2p[0]); 143 close(pipe_p2c[1]); 144 wait(NULL); 145} 146 147static void test_send_signal_tracepoint(bool signal_thread) 148{ 149 test_send_signal_common(NULL, signal_thread); 150} 151 152static void test_send_signal_perf(bool signal_thread) 153{ 154 struct perf_event_attr attr = { 155 .sample_period = 1, 156 .type = PERF_TYPE_SOFTWARE, 157 .config = PERF_COUNT_SW_CPU_CLOCK, 158 }; 159 160 test_send_signal_common(&attr, signal_thread); 161} 162 163static void test_send_signal_nmi(bool signal_thread) 164{ 165 struct perf_event_attr attr = { 166 .sample_period = 1, 167 .type = PERF_TYPE_HARDWARE, 168 .config = PERF_COUNT_HW_CPU_CYCLES, 169 }; 170 int pmu_fd; 171 172 /* Some setups (e.g. virtual machines) might run with hardware 173 * perf events disabled. If this is the case, skip this test. 174 */ 175 pmu_fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, 176 -1 /* cpu */, -1 /* group_fd */, 0 /* flags */); 177 if (pmu_fd == -1) { 178 if (errno == ENOENT) { 179 printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", 180 __func__); 181 test__skip(); 182 return; 183 } 184 /* Let the test fail with a more informative message */ 185 } else { 186 close(pmu_fd); 187 } 188 189 test_send_signal_common(&attr, signal_thread); 190} 191 192void test_send_signal(void) 193{ 194 if (test__start_subtest("send_signal_tracepoint")) 195 test_send_signal_tracepoint(false); 196 if (test__start_subtest("send_signal_perf")) 197 test_send_signal_perf(false); 198 if (test__start_subtest("send_signal_nmi")) 199 test_send_signal_nmi(false); 200 if (test__start_subtest("send_signal_tracepoint_thread")) 201 test_send_signal_tracepoint(true); 202 if (test__start_subtest("send_signal_perf_thread")) 203 test_send_signal_perf(true); 204 if (test__start_subtest("send_signal_nmi_thread")) 205 test_send_signal_nmi(true); 206}