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7#define _GNU_SOURCE
8
9#include <stdio.h>
10#include <sys/time.h>
11#include <time.h>
12#include <stdlib.h>
13#include <unistd.h>
14#include <sys/syscall.h>
15#include <dlfcn.h>
16#include <string.h>
17#include <errno.h>
18#include <sched.h>
19#include <stdbool.h>
20#include <limits.h>
21
22#ifndef SYS_getcpu
23# ifdef __x86_64__
24# define SYS_getcpu 309
25# else
26# define SYS_getcpu 318
27# endif
28#endif
29
30
31#define MAPS_LINE_LEN 128
32
33int nerrs = 0;
34
35typedef int (*vgettime_t)(clockid_t, struct timespec *);
36
37vgettime_t vdso_clock_gettime;
38
39typedef long (*vgtod_t)(struct timeval *tv, struct timezone *tz);
40
41vgtod_t vdso_gettimeofday;
42
43typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
44
45getcpu_t vgetcpu;
46getcpu_t vdso_getcpu;
47
48static void *vsyscall_getcpu(void)
49{
50#ifdef __x86_64__
51 FILE *maps;
52 char line[MAPS_LINE_LEN];
53 bool found = false;
54
55 maps = fopen("/proc/self/maps", "r");
56 if (!maps)
57 return NULL;
58
59 while (fgets(line, MAPS_LINE_LEN, maps)) {
60 char r, x;
61 void *start, *end;
62 char name[MAPS_LINE_LEN];
63
64
65 if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
66 &start, &end, &r, &x, name) != 5)
67 continue;
68
69 if (strcmp(name, "[vsyscall]"))
70 continue;
71
72
73 found = true;
74 break;
75 }
76
77 fclose(maps);
78
79 if (!found) {
80 printf("Warning: failed to find vsyscall getcpu\n");
81 return NULL;
82 }
83 return (void *) (0xffffffffff600800);
84#else
85 return NULL;
86#endif
87}
88
89
90static void fill_function_pointers()
91{
92 void *vdso = dlopen("linux-vdso.so.1",
93 RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
94 if (!vdso)
95 vdso = dlopen("linux-gate.so.1",
96 RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
97 if (!vdso) {
98 printf("[WARN]\tfailed to find vDSO\n");
99 return;
100 }
101
102 vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");
103 if (!vdso_getcpu)
104 printf("Warning: failed to find getcpu in vDSO\n");
105
106 vgetcpu = (getcpu_t) vsyscall_getcpu();
107
108 vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
109 if (!vdso_clock_gettime)
110 printf("Warning: failed to find clock_gettime in vDSO\n");
111
112 vdso_gettimeofday = (vgtod_t)dlsym(vdso, "__vdso_gettimeofday");
113 if (!vdso_gettimeofday)
114 printf("Warning: failed to find gettimeofday in vDSO\n");
115
116}
117
118static long sys_getcpu(unsigned * cpu, unsigned * node,
119 void* cache)
120{
121 return syscall(__NR_getcpu, cpu, node, cache);
122}
123
124static inline int sys_clock_gettime(clockid_t id, struct timespec *ts)
125{
126 return syscall(__NR_clock_gettime, id, ts);
127}
128
129static inline int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
130{
131 return syscall(__NR_gettimeofday, tv, tz);
132}
133
134static void test_getcpu(void)
135{
136 printf("[RUN]\tTesting getcpu...\n");
137
138 for (int cpu = 0; ; cpu++) {
139 cpu_set_t cpuset;
140 CPU_ZERO(&cpuset);
141 CPU_SET(cpu, &cpuset);
142 if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
143 return;
144
145 unsigned cpu_sys, cpu_vdso, cpu_vsys,
146 node_sys, node_vdso, node_vsys;
147 long ret_sys, ret_vdso = 1, ret_vsys = 1;
148 unsigned node;
149
150 ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
151 if (vdso_getcpu)
152 ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
153 if (vgetcpu)
154 ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
155
156 if (!ret_sys)
157 node = node_sys;
158 else if (!ret_vdso)
159 node = node_vdso;
160 else if (!ret_vsys)
161 node = node_vsys;
162
163 bool ok = true;
164 if (!ret_sys && (cpu_sys != cpu || node_sys != node))
165 ok = false;
166 if (!ret_vdso && (cpu_vdso != cpu || node_vdso != node))
167 ok = false;
168 if (!ret_vsys && (cpu_vsys != cpu || node_vsys != node))
169 ok = false;
170
171 printf("[%s]\tCPU %u:", ok ? "OK" : "FAIL", cpu);
172 if (!ret_sys)
173 printf(" syscall: cpu %u, node %u", cpu_sys, node_sys);
174 if (!ret_vdso)
175 printf(" vdso: cpu %u, node %u", cpu_vdso, node_vdso);
176 if (!ret_vsys)
177 printf(" vsyscall: cpu %u, node %u", cpu_vsys,
178 node_vsys);
179 printf("\n");
180
181 if (!ok)
182 nerrs++;
183 }
184}
185
186static bool ts_leq(const struct timespec *a, const struct timespec *b)
187{
188 if (a->tv_sec != b->tv_sec)
189 return a->tv_sec < b->tv_sec;
190 else
191 return a->tv_nsec <= b->tv_nsec;
192}
193
194static bool tv_leq(const struct timeval *a, const struct timeval *b)
195{
196 if (a->tv_sec != b->tv_sec)
197 return a->tv_sec < b->tv_sec;
198 else
199 return a->tv_usec <= b->tv_usec;
200}
201
202static char const * const clocknames[] = {
203 [0] = "CLOCK_REALTIME",
204 [1] = "CLOCK_MONOTONIC",
205 [2] = "CLOCK_PROCESS_CPUTIME_ID",
206 [3] = "CLOCK_THREAD_CPUTIME_ID",
207 [4] = "CLOCK_MONOTONIC_RAW",
208 [5] = "CLOCK_REALTIME_COARSE",
209 [6] = "CLOCK_MONOTONIC_COARSE",
210 [7] = "CLOCK_BOOTTIME",
211 [8] = "CLOCK_REALTIME_ALARM",
212 [9] = "CLOCK_BOOTTIME_ALARM",
213 [10] = "CLOCK_SGI_CYCLE",
214 [11] = "CLOCK_TAI",
215};
216
217static void test_one_clock_gettime(int clock, const char *name)
218{
219 struct timespec start, vdso, end;
220 int vdso_ret, end_ret;
221
222 printf("[RUN]\tTesting clock_gettime for clock %s (%d)...\n", name, clock);
223
224 if (sys_clock_gettime(clock, &start) < 0) {
225 if (errno == EINVAL) {
226 vdso_ret = vdso_clock_gettime(clock, &vdso);
227 if (vdso_ret == -EINVAL) {
228 printf("[OK]\tNo such clock.\n");
229 } else {
230 printf("[FAIL]\tNo such clock, but __vdso_clock_gettime returned %d\n", vdso_ret);
231 nerrs++;
232 }
233 } else {
234 printf("[WARN]\t clock_gettime(%d) syscall returned error %d\n", clock, errno);
235 }
236 return;
237 }
238
239 vdso_ret = vdso_clock_gettime(clock, &vdso);
240 end_ret = sys_clock_gettime(clock, &end);
241
242 if (vdso_ret != 0 || end_ret != 0) {
243 printf("[FAIL]\tvDSO returned %d, syscall errno=%d\n",
244 vdso_ret, errno);
245 nerrs++;
246 return;
247 }
248
249 printf("\t%llu.%09ld %llu.%09ld %llu.%09ld\n",
250 (unsigned long long)start.tv_sec, start.tv_nsec,
251 (unsigned long long)vdso.tv_sec, vdso.tv_nsec,
252 (unsigned long long)end.tv_sec, end.tv_nsec);
253
254 if (!ts_leq(&start, &vdso) || !ts_leq(&vdso, &end)) {
255 printf("[FAIL]\tTimes are out of sequence\n");
256 nerrs++;
257 }
258}
259
260static void test_clock_gettime(void)
261{
262 for (int clock = 0; clock < sizeof(clocknames) / sizeof(clocknames[0]);
263 clock++) {
264 test_one_clock_gettime(clock, clocknames[clock]);
265 }
266
267
268 test_one_clock_gettime(-1, "invalid");
269 test_one_clock_gettime(INT_MIN, "invalid");
270 test_one_clock_gettime(INT_MAX, "invalid");
271}
272
273static void test_gettimeofday(void)
274{
275 struct timeval start, vdso, end;
276 struct timezone sys_tz, vdso_tz;
277 int vdso_ret, end_ret;
278
279 if (!vdso_gettimeofday)
280 return;
281
282 printf("[RUN]\tTesting gettimeofday...\n");
283
284 if (sys_gettimeofday(&start, &sys_tz) < 0) {
285 printf("[FAIL]\tsys_gettimeofday failed (%d)\n", errno);
286 nerrs++;
287 return;
288 }
289
290 vdso_ret = vdso_gettimeofday(&vdso, &vdso_tz);
291 end_ret = sys_gettimeofday(&end, NULL);
292
293 if (vdso_ret != 0 || end_ret != 0) {
294 printf("[FAIL]\tvDSO returned %d, syscall errno=%d\n",
295 vdso_ret, errno);
296 nerrs++;
297 return;
298 }
299
300 printf("\t%llu.%06ld %llu.%06ld %llu.%06ld\n",
301 (unsigned long long)start.tv_sec, start.tv_usec,
302 (unsigned long long)vdso.tv_sec, vdso.tv_usec,
303 (unsigned long long)end.tv_sec, end.tv_usec);
304
305 if (!tv_leq(&start, &vdso) || !tv_leq(&vdso, &end)) {
306 printf("[FAIL]\tTimes are out of sequence\n");
307 nerrs++;
308 }
309
310 if (sys_tz.tz_minuteswest == vdso_tz.tz_minuteswest &&
311 sys_tz.tz_dsttime == vdso_tz.tz_dsttime) {
312 printf("[OK]\ttimezones match: minuteswest=%d, dsttime=%d\n",
313 sys_tz.tz_minuteswest, sys_tz.tz_dsttime);
314 } else {
315 printf("[FAIL]\ttimezones do not match\n");
316 nerrs++;
317 }
318
319
320 vdso_gettimeofday(&vdso, NULL);
321}
322
323int main(int argc, char **argv)
324{
325 fill_function_pointers();
326
327 test_clock_gettime();
328 test_gettimeofday();
329
330
331
332
333
334 test_getcpu();
335
336 return nerrs ? 1 : 0;
337}
338
