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