1 /*
2 * Copyright 2014, Michael Ellerman, IBM Corp.
3 * Licensed under GPLv2.
4 */
5
6 #define _GNU_SOURCE /* For CPU_ZERO etc. */
7
8 #include <errno.h>
9 #include <sched.h>
10 #include <setjmp.h>
11 #include <stdlib.h>
12 #include <sys/wait.h>
13
14 #include "utils.h"
15 #include "lib.h"
16
17
bind_to_cpu(int cpu)18 int bind_to_cpu(int cpu)
19 {
20 cpu_set_t mask;
21
22 printf("Binding to cpu %d\n", cpu);
23
24 CPU_ZERO(&mask);
25 CPU_SET(cpu, &mask);
26
27 return sched_setaffinity(0, sizeof(mask), &mask);
28 }
29
30 #define PARENT_TOKEN 0xAA
31 #define CHILD_TOKEN 0x55
32
sync_with_child(union pipe read_pipe,union pipe write_pipe)33 int sync_with_child(union pipe read_pipe, union pipe write_pipe)
34 {
35 char c = PARENT_TOKEN;
36
37 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
38 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
39 if (c != CHILD_TOKEN) /* sometimes expected */
40 return 1;
41
42 return 0;
43 }
44
wait_for_parent(union pipe read_pipe)45 int wait_for_parent(union pipe read_pipe)
46 {
47 char c;
48
49 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
50 FAIL_IF(c != PARENT_TOKEN);
51
52 return 0;
53 }
54
notify_parent(union pipe write_pipe)55 int notify_parent(union pipe write_pipe)
56 {
57 char c = CHILD_TOKEN;
58
59 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
60
61 return 0;
62 }
63
notify_parent_of_error(union pipe write_pipe)64 int notify_parent_of_error(union pipe write_pipe)
65 {
66 char c = ~CHILD_TOKEN;
67
68 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
69
70 return 0;
71 }
72
wait_for_child(pid_t child_pid)73 int wait_for_child(pid_t child_pid)
74 {
75 int rc;
76
77 if (waitpid(child_pid, &rc, 0) == -1) {
78 perror("waitpid");
79 return 1;
80 }
81
82 if (WIFEXITED(rc))
83 rc = WEXITSTATUS(rc);
84 else
85 rc = 1; /* Signal or other */
86
87 return rc;
88 }
89
kill_child_and_wait(pid_t child_pid)90 int kill_child_and_wait(pid_t child_pid)
91 {
92 kill(child_pid, SIGTERM);
93
94 return wait_for_child(child_pid);
95 }
96
eat_cpu_child(union pipe read_pipe,union pipe write_pipe)97 static int eat_cpu_child(union pipe read_pipe, union pipe write_pipe)
98 {
99 volatile int i = 0;
100
101 /*
102 * We are just here to eat cpu and die. So make sure we can be killed,
103 * and also don't do any custom SIGTERM handling.
104 */
105 signal(SIGTERM, SIG_DFL);
106
107 notify_parent(write_pipe);
108 wait_for_parent(read_pipe);
109
110 /* Soak up cpu forever */
111 while (1) i++;
112
113 return 0;
114 }
115
eat_cpu(int (test_function)(void))116 pid_t eat_cpu(int (test_function)(void))
117 {
118 union pipe read_pipe, write_pipe;
119 int cpu, rc;
120 pid_t pid;
121
122 cpu = pick_online_cpu();
123 FAIL_IF(cpu < 0);
124 FAIL_IF(bind_to_cpu(cpu));
125
126 if (pipe(read_pipe.fds) == -1)
127 return -1;
128
129 if (pipe(write_pipe.fds) == -1)
130 return -1;
131
132 pid = fork();
133 if (pid == 0)
134 exit(eat_cpu_child(write_pipe, read_pipe));
135
136 if (sync_with_child(read_pipe, write_pipe)) {
137 rc = -1;
138 goto out;
139 }
140
141 printf("main test running as pid %d\n", getpid());
142
143 rc = test_function();
144 out:
145 kill(pid, SIGKILL);
146
147 return rc;
148 }
149
150 struct addr_range libc, vdso;
151
parse_proc_maps(void)152 int parse_proc_maps(void)
153 {
154 unsigned long start, end;
155 char execute, name[128];
156 FILE *f;
157 int rc;
158
159 f = fopen("/proc/self/maps", "r");
160 if (!f) {
161 perror("fopen");
162 return -1;
163 }
164
165 do {
166 /* This skips line with no executable which is what we want */
167 rc = fscanf(f, "%lx-%lx %*c%*c%c%*c %*x %*d:%*d %*d %127s\n",
168 &start, &end, &execute, name);
169 if (rc <= 0)
170 break;
171
172 if (execute != 'x')
173 continue;
174
175 if (strstr(name, "libc")) {
176 libc.first = start;
177 libc.last = end - 1;
178 } else if (strstr(name, "[vdso]")) {
179 vdso.first = start;
180 vdso.last = end - 1;
181 }
182 } while(1);
183
184 fclose(f);
185
186 return 0;
187 }
188
189 #define PARANOID_PATH "/proc/sys/kernel/perf_event_paranoid"
190
require_paranoia_below(int level)191 bool require_paranoia_below(int level)
192 {
193 long current;
194 char *end, buf[16];
195 FILE *f;
196 bool rc;
197
198 rc = false;
199
200 f = fopen(PARANOID_PATH, "r");
201 if (!f) {
202 perror("fopen");
203 goto out;
204 }
205
206 if (!fgets(buf, sizeof(buf), f)) {
207 printf("Couldn't read " PARANOID_PATH "?\n");
208 goto out_close;
209 }
210
211 current = strtol(buf, &end, 10);
212
213 if (end == buf) {
214 printf("Couldn't parse " PARANOID_PATH "?\n");
215 goto out_close;
216 }
217
218 if (current >= level)
219 goto out_close;
220
221 rc = true;
222 out_close:
223 fclose(f);
224 out:
225 return rc;
226 }
227
228