1 | #include <time.h>
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2 | #include <errno.h>
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3 | #include <stdint.h>
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4 | #include "syscall.h"
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5 | #include "libc.h"
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6 | #include "atomic.h"
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7 |
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8 | #ifdef VDSO_CGT_SYM
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9 |
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10 | void *__vdsosym(const char *, const char *);
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11 |
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12 | static void *volatile vdso_func;
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13 |
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14 | static int cgt_init(clockid_t clk, struct timespec *ts)
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15 | {
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16 | void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
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17 | int (*f)(clockid_t, struct timespec *) =
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18 | (int (*)(clockid_t, struct timespec *))p;
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19 | a_cas_p(&vdso_func, (void *)cgt_init, p);
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20 | return f ? f(clk, ts) : -ENOSYS;
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21 | }
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22 |
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23 | static void *volatile vdso_func = (void *)cgt_init;
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24 |
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25 | #endif
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26 |
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27 | int __clock_gettime(clockid_t clk, struct timespec *ts)
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28 | {
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29 | int r;
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30 |
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31 | #ifdef VDSO_CGT_SYM
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32 | int (*f)(clockid_t, struct timespec *) =
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33 | (int (*)(clockid_t, struct timespec *))vdso_func;
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34 | if (f) {
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35 | r = f(clk, ts);
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36 | if (!r) return r;
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37 | if (r == -EINVAL) return __syscall_ret(r);
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38 | /* Fall through on errors other than EINVAL. Some buggy
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39 | * vdso implementations return ENOSYS for clocks they
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40 | * can't handle, rather than making the syscall. This
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41 | * also handles the case where cgt_init fails to find
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42 | * a vdso function to use. */
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43 | }
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44 | #endif
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45 |
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46 | r = __syscall(SYS_clock_gettime, clk, ts);
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47 | if (r == -ENOSYS) {
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48 | if (clk == CLOCK_REALTIME) {
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49 | __syscall(SYS_gettimeofday, ts, 0);
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50 | ts->tv_nsec = (int)ts->tv_nsec * 1000;
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51 | return 0;
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52 | }
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53 | r = -EINVAL;
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54 | }
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55 | return __syscall_ret(r);
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56 | }
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57 |
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58 | weak_alias(__clock_gettime, clock_gettime);
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